Pub Date : 2019-01-15DOI: 10.17073/0368-0797-2018-12-939-947
В. А. Быстров
Composite materials (CM) are widely used for hardening of wearing parts operating at high temperature wear types. They are based on high-melting hard alloys, as which are used carbides of transition metals of IV – VI groups A determining the physics of high-temperature wear. For these purposes baked TiC of TN 20 type on the basis of (Ti, Mo)C – Ni – Mo is used that has a ring structure preventing the formation of complex alloyed structures on the bounda ry of solid particle-matrix. Due to the minimal solubility of the sintered hard alloy of TN 20 type in the alloy-bond, at the interface of solid particle – matrix practically does not stand out complex structural phases causing embrittlement and growth of residual thermal stresses and strains. It leads to increased wear resistance and longer service life of hardened parts. In order to increase the opera ting efficiency of metallurgical units due to hardening of spare parts with a composite material based on sintered hard alloy of the TN 20 type using electroslag surfacing (ESW), a comprehensive program has been developed to control the efficiency of hardening parts. In the management of hard alloy surfacing the special attention is given to heat and high temperature wear resistance determined by the set of CM properties of solid particles. Therefore, maintaining of high mechanical, thermal and energy characteristics of carbides and decrease of the solubility of solid particles in a CM matrix at surfacing is a priority for improving efficiency in hardening process of spare parts. Integrated ESW management program for CM is based on effects, aimed to prevent the formation of complex alloyed structures on surface of the solid section of particle-matrix; to reduce thermal stresses and deformations (leading to the cracks formation, chipping and deleting solid particles in abrasive wear) and to improve high temperature wear resistance. Use of the developed control systems for hardening process of metallurgical equipment wearing parts has significantly increased the service life of spare parts and producti vity of the metallurgical units, which ensured a certain economic effect.
复合材料(CM)广泛应用于高温磨损工况下易损件的硬化处理。它们是基于高熔点的硬质合金，其中使用了IV - VI族A过渡金属的碳化物，决定了高温磨损的物理性质。为此，采用了以(Ti, Mo)C - Ni - Mo为基础的tn20型焙烧TiC，其具有环状结构，可防止在固体颗粒基体边界上形成复杂的合金结构。由于tn20型硬质合金烧结后在合金结合部的溶解度极低，在固体颗粒-基体界面处几乎不出现复杂的组织相，导致残余热应力和应变的脆化和增长。使硬化零件的耐磨性提高，使用寿命延长。为了提高冶金机组因使用电渣堆焊tn20型硬质合金烧结复合材料对零件进行淬火而产生的运行效率，制定了一套控制零件淬火效率的综合方案。在硬质合金堆焊管理中，应特别注意由固体颗粒的一组CM特性决定的耐热性和高温耐磨性。因此，在堆焊时保持碳化物的高力学、热学和能量特性，降低固体颗粒在CM基体中的溶解度，是提高零件硬化工艺效率的首要任务。粉末冶金综合ESW管理方案以效果为基础，旨在防止颗粒基体固体截面表面形成复杂的合金组织;减少热应力和变形(导致磨料磨损时产生裂纹、切屑和去除固体颗粒)，提高高温耐磨性。开发的冶金设备易损件硬化过程控制系统的应用，显著提高了备件的使用寿命和冶金装置的生产率，保证了一定的经济效益。
{"title":"ЭФФЕКТИВНОСТЬ УПРОЧНЕНИЯ ТВЕРДЫМ СПЛАВОМ СМЕННЫХ ДЕТАЛЕЙ МЕТАЛЛУРГИЧЕСКИХ АГРЕГАТОВ","authors":"В. А. Быстров","doi":"10.17073/0368-0797-2018-12-939-947","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-12-939-947","url":null,"abstract":"Composite materials (CM) are widely used for hardening of wearing parts operating at high temperature wear types. They are based on high-melting hard alloys, as which are used carbides of transition metals of IV – VI groups A determining the physics of high-temperature wear. For these purposes baked TiC of TN 20 type on the basis of (Ti, Mo)C – Ni – Mo is used that has a ring structure preventing the formation of complex alloyed structures on the bounda ry of solid particle-matrix. Due to the minimal solubility of the sintered hard alloy of TN 20 type in the alloy-bond, at the interface of solid particle – matrix practically does not stand out complex structural phases causing embrittlement and growth of residual thermal stresses and strains. It leads to increased wear resistance and longer service life of hardened parts. In order to increase the opera ting efficiency of metallurgical units due to hardening of spare parts with a composite material based on sintered hard alloy of the TN 20 type using electroslag surfacing (ESW), a comprehensive program has been developed to control the efficiency of hardening parts. In the management of hard alloy surfacing the special attention is given to heat and high temperature wear resistance determined by the set of CM properties of solid particles. Therefore, maintaining of high mechanical, thermal and energy characteristics of carbides and decrease of the solubility of solid particles in a CM matrix at surfacing is a priority for improving efficiency in hardening process of spare parts. Integrated ESW management program for CM is based on effects, aimed to prevent the formation of complex alloyed structures on surface of the solid section of particle-matrix; to reduce thermal stresses and deformations (leading to the cracks formation, chipping and deleting solid particles in abrasive wear) and to improve high temperature wear resistance. Use of the developed control systems for hardening process of metallurgical equipment wearing parts has significantly increased the service life of spare parts and producti vity of the metallurgical units, which ensured a certain economic effect.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80546321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-15DOI: 10.17073/0368-0797-2018-12-927-932
В. Ю. Рубцов, Ольга Ивановна Шевченко, М. В. Миронова
One of the important reasons for the downtime of ball rolling mills is replacement of rolls due to their wear and tear. The degree and zones of critical wear of ball rolling rolls are investigated in the article, where the greatest wear is observed over the flanges in zone of billet capture. Conditions necessary to capture the blank and to perform rolling process are analytically determined. Variable frequency method of roll rotations is proposed as a progressive technology for blank supply. The results of tests for its variations in accordance with linear and quadratic law are presented. Known formulas determining average strain rate at rolls rotational speed change are converted for linear and quadratic dependences. Experimental studies have been carried out in conditions of EVRAZ Nizhnetagilsky Metallurgical Plant ball rolling mills during rolling of 60mm ball made of Sh-3G steel. Experiments were performed for given parameters of manual change in rolls rotation speed at blank capture by rollers. The results have shown a significant effect of change in rotational speed on average specific pressure during blank capture. Evaluation of torque-time and average contact pressure for calculated and experimental data are presented. Empirical characteristics are also described at variable rotational speed of rolls according to linear and quadratic law. Acceptable convergence of results of calculated and empirical characteristics is determined. Engineering solution has been proposed for that task. It consists in installation of a thyristor converter. This solution allows reduction of rolls speed before blank capture. Also, this solution will increase frequency to the nominal value according to the given law after blank capture. As an obtained result, there is uniform distribution of average contact pressure over the entire length of the roll under different operating conditions of mill in automatic mode. Application of this technique will reduce wear degree of the rolling tool. At the same time, productivity of ball rolling mill will be maintained. Rolls consumption and number of rolls change will decrease due to rolls wear.
{"title":"СОВЕРШЕНСТВОВАНИЕ ДИНАМИЧЕСКОГО РЕЖИМА ПРОКАТКИ ДЛЯ ПОВЫШЕНИЯ СТОЙКОСТИ ВАЛКОВ ШАРОПРОКАТНОГО СТАНА","authors":"В. Ю. Рубцов, Ольга Ивановна Шевченко, М. В. Миронова","doi":"10.17073/0368-0797-2018-12-927-932","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-12-927-932","url":null,"abstract":"One of the important reasons for the downtime of ball rolling mills is replacement of rolls due to their wear and tear. The degree and zones of critical wear of ball rolling rolls are investigated in the article, where the greatest wear is observed over the flanges in zone of billet capture. Conditions necessary to capture the blank and to perform rolling process are analytically determined. Variable frequency method of roll rotations is proposed as a progressive technology for blank supply. The results of tests for its variations in accordance with linear and quadratic law are presented. Known formulas determining average strain rate at rolls rotational speed change are converted for linear and quadratic dependences. Experimental studies have been carried out in conditions of EVRAZ Nizhnetagilsky Metallurgical Plant ball rolling mills during rolling of 60mm ball made of Sh-3G steel. Experiments were performed for given parameters of manual change in rolls rotation speed at blank capture by rollers. The results have shown a significant effect of change in rotational speed on average specific pressure during blank capture. Evaluation of torque-time and average contact pressure for calculated and experimental data are presented. Empirical characteristics are also described at variable rotational speed of rolls according to linear and quadratic law. Acceptable convergence of results of calculated and empirical characteristics is determined. Engineering solution has been proposed for that task. It consists in installation of a thyristor converter. This solution allows reduction of rolls speed before blank capture. Also, this solution will increase frequency to the nominal value according to the given law after blank capture. As an obtained result, there is uniform distribution of average contact pressure over the entire length of the roll under different operating conditions of mill in automatic mode. Application of this technique will reduce wear degree of the rolling tool. At the same time, productivity of ball rolling mill will be maintained. Rolls consumption and number of rolls change will decrease due to rolls wear.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78939895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-15DOI: 10.17073/0368-0797-2018-12-948-956
Леонид Яковлевич Левков, Д. А. Шурыгин, В. С. Дуб, В. В. Клочай, Е. Л. Корзун
Billets from high-chromium steels possessing the necessary complex of mechanical and corrosion properties are widely used in the manufacture of critical products of heavy and power engineering. One of the effective technologies widely used in the manufacture of such work-pieces is electroslag remelting (ESR). ESR, included in the production process chain, for the management of refining and solidification processes allows to ensure a high homogeneity of metallurgical characteristics (chemical composition, structure, non-metallic inclusions, etc.) of the metal and, as a result, the complex of mechanical properties of the product. The choice of slag, maintaining its optimum oxidation-reduction potential at an optimum level, is a prerequisite for the effective refining of high-chromium steels at the ESR, since chromium and other elements present in the slag in various oxidation degree participate in the transport of oxygen from the gas phase to the liquid metal. From standpoint of the theory of electronic structure of slag systems, the effect of slag oxidation (equilibrium partial pressure of oxygen Р O 2 ) on the oxidation degree of chromium has been studied for widely used slags in Russia such as ANF-1, ANF-6, and ANF-29. Dependence of the ratio of Cr +3 /Cr +2 concentrations on the temperature, oxidation level and optical slag basicity is established. A thermodynamic model of changing the oxidation state of chromium in slag depending on its oxidation is presented. The calculated results are compared with the experimental data for slag systems at a temperature of 1873 K. It is shown that the average oxidation degree of chromium decreases with increasing temperature, decreasing of the oxygen partial pressure and the optical slag basicity. The presence of fluorine in the slag affects the varia- tion ratio Cr +3 /Cr +2 . It is shown that with decrease in the oxygen partial pressure from 10 -4 to 10 -12 Pa at a temperature of 1873 K, the average value of chromium oxidation degree in fluoride-oxide slags decreases from +3 to +2. A correlation is proposed, which makes it possible to estimate the Cr +3 /Cr +2 ratio in fluoride-oxide slags, taking into account the temperature and oxidation of slag.
{"title":"ИССЛЕДОВАНИЕ СТЕПЕНИ ОКИСЛЕНИЯ ХРОМА В ОКСИДНО-ФТОРИДНЫХ ШЛАКАХ, ПРИМЕНЯЕМЫХ ПРИ ЭЛЕКТРОШЛАКОВОМ ПЕРЕПЛАВЕ","authors":"Леонид Яковлевич Левков, Д. А. Шурыгин, В. С. Дуб, В. В. Клочай, Е. Л. Корзун","doi":"10.17073/0368-0797-2018-12-948-956","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-12-948-956","url":null,"abstract":"Billets from high-chromium steels possessing the necessary complex of mechanical and corrosion properties are widely used in the manufacture of critical products of heavy and power engineering. One of the effective technologies widely used in the manufacture of such work-pieces is electroslag remelting (ESR). ESR, included in the production process chain, for the management of refining and solidification processes allows to ensure a high homogeneity of metallurgical characteristics (chemical composition, structure, non-metallic inclusions, etc.) of the metal and, as a result, the complex of mechanical properties of the product. The choice of slag, maintaining its optimum oxidation-reduction potential at an optimum level, is a prerequisite for the effective refining of high-chromium steels at the ESR, since chromium and other elements present in the slag in various oxidation degree participate in the transport of oxygen from the gas phase to the liquid metal. From standpoint of the theory of electronic structure of slag systems, the effect of slag oxidation (equilibrium partial pressure of oxygen Р O 2 ) on the oxidation degree of chromium has been studied for widely used slags in Russia such as ANF-1, ANF-6, and ANF-29. Dependence of the ratio of Cr +3 /Cr +2 concentrations on the temperature, oxidation level and optical slag basicity is established. A thermodynamic model of changing the oxidation state of chromium in slag depending on its oxidation is presented. The calculated results are compared with the experimental data for slag systems at a temperature of 1873 K. It is shown that the average oxidation degree of chromium decreases with increasing temperature, decreasing of the oxygen partial pressure and the optical slag basicity. The presence of fluorine in the slag affects the varia- tion ratio Cr +3 /Cr +2 . It is shown that with decrease in the oxygen partial pressure from 10 -4 to 10 -12 Pa at a temperature of 1873 K, the average value of chromium oxidation degree in fluoride-oxide slags decreases from +3 to +2. A correlation is proposed, which makes it possible to estimate the Cr +3 /Cr +2 ratio in fluoride-oxide slags, taking into account the temperature and oxidation of slag.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76210074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-15DOI: 10.17073/0368-0797-2018-12-933-938
А. В. Дмитриенко, Евгений Валентинович Протопопов, В. И. Дмитриенко, Н. Ф. Якушевич, В. Ф. Горюшкин
One of the directions of increasing production efficiency in ferrous metallurgy is reduction of expensive and scarce ferroalloy consumption. Great opportunities in that direction are provided by technology of direct steel alloying by oxide materials. Thermodynamic study of the process of direct steel alloying by manganese oxide materials (manganese ore) and industrial testing of that technology has been done in that work. Two options of direct alloying technology have been considered: during steel melting in modern 100-ton EAF in oxidative conditions and during processing of steel on ladle furnace (LF) in reductive conditions. Thermodynamic modeling of oxidative technology option by TERRA software package has shown that there is opportunity to increase content of manganese in metal by manganese ore injection. Key factor in that process is current carbon content in steel. Content of manganese can be raised up to 0.6 % and more in medium and high-carbon steel. Residual manganese in low-carbon steel is defined by value of carbon content in the end of oxygen lancing. Graphic dependence is provided. MnO + Si = Mn + SiO 2 is main reaction of the process of direct alloying under reductive conditions. Thermodynamic analysis gives very rough data. That is why semi-empirical analysis was performed, which was based on received industrial results of FeO and MnO proportion contained in slag in the end of steel processing at LF. That way of process estimation is considered reasonable, because of approximation to balance of metal-slag system during long processing of steel at LF. Using this proportion, and conditions of slag initial basicity retaining and maintaining of FeO content in slag at level around 1 %, balance equation describing process of direct steel alloying by manganese ore at ladle was derived. This equation helps to calculate basic technological parameters of the process of direct alloying by manganese ore as applied to specific conditions of production. Good convergence of theoretical calculation and practical data has been received.
降低昂贵而稀缺的铁合金用量是提高铁冶金生产效率的方向之一。氧化物材料直接合金化钢的技术为这一方向提供了巨大的机会。对锰氧化物材料(锰矿石)直接合金化钢的过程进行了热力学研究，并对该工艺进行了工业试验。考虑了两种直接合金化技术的选择:在现代100吨电弧炉的氧化条件下熔化钢和在钢包炉(LF)的还原条件下加工钢。利用TERRA软件包对氧化工艺选项进行热力学建模，结果表明，注入锰矿石有可能提高金属中锰的含量。这个过程的关键因素是当前钢中的含碳量。在中高碳钢中，锰的含量可提高到0.6%以上。低碳钢的残锰量是由氧氧化结束时的含碳量来确定的。提供图形依赖。MnO + Si = Mn + sio2是还原条件下直接合金化过程的主要反应。热力学分析给出了非常粗略的数据。因此，本文采用了半经验分析的方法，以LF炼钢后期炉渣中FeO和MnO含量的工业实测结果为基础。由于该方法近似于LF长时间炼钢过程中金属渣体系的平衡，因此认为该方法是合理的。利用这一比例，在渣初碱度保持和渣中FeO含量保持在1%左右的条件下，推导出了钢包锰矿直接合金化钢过程的平衡方程。该方程可应用于具体生产条件，计算锰矿石直接合金化工艺的基本工艺参数。理论计算与实际数据具有较好的收敛性。
{"title":"ИЗУЧЕНИЕ ПРОЦЕССА ПРЯМОГО ЛЕГИРОВАНИЯ СТАЛИ МАРГАНЦЕМ В УСЛОВИЯХ СОВРЕМЕННОГО ЭЛЕКТРОСТАЛЕПЛАВИЛЬНОГО ПРОИЗВОДСТВА","authors":"А. В. Дмитриенко, Евгений Валентинович Протопопов, В. И. Дмитриенко, Н. Ф. Якушевич, В. Ф. Горюшкин","doi":"10.17073/0368-0797-2018-12-933-938","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-12-933-938","url":null,"abstract":"One of the directions of increasing production efficiency in ferrous metallurgy is reduction of expensive and scarce ferroalloy consumption. Great opportunities in that direction are provided by technology of direct steel alloying by oxide materials. Thermodynamic study of the process of direct steel alloying by manganese oxide materials (manganese ore) and industrial testing of that technology has been done in that work. Two options of direct alloying technology have been considered: during steel melting in modern 100-ton EAF in oxidative conditions and during processing of steel on ladle furnace (LF) in reductive conditions. Thermodynamic modeling of oxidative technology option by TERRA software package has shown that there is opportunity to increase content of manganese in metal by manganese ore injection. Key factor in that process is current carbon content in steel. Content of manganese can be raised up to 0.6 % and more in medium and high-carbon steel. Residual manganese in low-carbon steel is defined by value of carbon content in the end of oxygen lancing. Graphic dependence is provided. MnO + Si = Mn + SiO 2 is main reaction of the process of direct alloying under reductive conditions. Thermodynamic analysis gives very rough data. That is why semi-empirical analysis was performed, which was based on received industrial results of FeO and MnO proportion contained in slag in the end of steel processing at LF. That way of process estimation is considered reasonable, because of approximation to balance of metal-slag system during long processing of steel at LF. Using this proportion, and conditions of slag initial basicity retaining and maintaining of FeO content in slag at level around 1 %, balance equation describing process of direct steel alloying by manganese ore at ladle was derived. This equation helps to calculate basic technological parameters of the process of direct alloying by manganese ore as applied to specific conditions of production. Good convergence of theoretical calculation and practical data has been received.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91346649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-24DOI: 10.17073/0368-0797-2018-11-920-921
N. I. Zakharov, I. V. Tupilko
In computer simulation of heat and mass transfer at metals ladle degassing (with a sufficiently high melting point) from the dissolved nitrogen in electrostatic field of subcritical tensions, there is a problem of statement of a boundary condition to the equation of convective diffusion on border “vacuum - metal”. The purpose of computer simulation was the technology optimization. Classical form of the Siverts law doesn’t consider the external impact on fusion. The authors offer the generalizing record of this law which includes tension of the electrostatic field and extent of atoms ionization of nitrogen dissolved in metal in upper layer of this border. Its correctness is confirmed by three-criteria check.
{"title":"Application of siverts law to the study of heat and mass transfer processes during the molten metals degassing from dissolved nitrogen in an electrostatic field of subcritical strengths","authors":"N. I. Zakharov, I. V. Tupilko","doi":"10.17073/0368-0797-2018-11-920-921","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-11-920-921","url":null,"abstract":"In computer simulation of heat and mass transfer at metals ladle degassing (with a sufficiently high melting point) from the dissolved nitrogen in electrostatic field of subcritical tensions, there is a problem of statement of a boundary condition to the equation of convective diffusion on border “vacuum - metal”. The purpose of computer simulation was the technology optimization. Classical form of the Siverts law doesn’t consider the external impact on fusion. The authors offer the generalizing record of this law which includes tension of the electrostatic field and extent of atoms ionization of nitrogen dissolved in metal in upper layer of this border. Its correctness is confirmed by three-criteria check.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77074155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-24DOI: 10.17073/0368-0797-2018-11-843-858
Д. В. Зиновеев, Павел Иванович Грудинский, Валерий Григорьевич Дюбанов, Л. В. Коваленко, Леопольд Игоревич Леонтьев
This review considers the papers aimed to find an effective solution to the red mud utilization problem. Red mud or bauxite residue is a hazardous materials that are generating during production of alumina by the Bayer process. Depending on the composition of bauxite and the technology, production of 1 ton alumina forms from 0.9 to 1.5 tons of this waste. The global inventory of red mud is estimated at about 4 billion ton in 2015. The main quantity of bauxite residue is not processed, but pumped into land-based ponds and it leads to environmental pollution. In 2010 in Hungary a pond containing red mud were collapsed, freeing about 700 thousand m3 of liquid waste, as a result 10 people were died, about 350 houses were destroyed and significant regions were polluted. Red mud obtained by different plants has various chemical and phase compositions. Despite this fact the main components of red mud is iron-containing minerals, so bauxite residue can be considered primarily as a raw material for the metallurgical industry. This part of the review considers pyrometallurgical methods for of red mud treatment, including both methods of low-temperature reduction at temperatures of 1050 - 1200 °C and high-temperature reduction melting, as well as utilization methods of the resulting slags. These slag utilization methods can be used for extraction of alumina, titanium and rare-earth metals, obtaining building materials such as various cements, mineral wool and flux materials for metallurgy. Methods of alkali removing, drying and agglomeration of red mud also considered. It has been shown that the best ways of bauxite residue recycling are the pyrometallurgical methods with obtaining of iron-containing product and slag for the production of building materials or metallurgical fluxes. These techniques make possible to utilize a large amount of red mud with exception of additional waste formation. This is the first part in a series of three related reviews examining the world experience of red mud recycling by various ways.
{"title":"Обзор мировой практики переработки красных шламов. Часть 1. Пирометаллургические способы","authors":"Д. В. Зиновеев, Павел Иванович Грудинский, Валерий Григорьевич Дюбанов, Л. В. Коваленко, Леопольд Игоревич Леонтьев","doi":"10.17073/0368-0797-2018-11-843-858","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-11-843-858","url":null,"abstract":"This review considers the papers aimed to find an effective solution to the red mud utilization problem. Red mud or bauxite residue is a hazardous materials that are generating during production of alumina by the Bayer process. Depending on the composition of bauxite and the technology, production of 1 ton alumina forms from 0.9 to 1.5 tons of this waste. The global inventory of red mud is estimated at about 4 billion ton in 2015. The main quantity of bauxite residue is not processed, but pumped into land-based ponds and it leads to environmental pollution. In 2010 in Hungary a pond containing red mud were collapsed, freeing about 700 thousand m3 of liquid waste, as a result 10 people were died, about 350 houses were destroyed and significant regions were polluted. Red mud obtained by different plants has various chemical and phase compositions. Despite this fact the main components of red mud is iron-containing minerals, so bauxite residue can be considered primarily as a raw material for the metallurgical industry. This part of the review considers pyrometallurgical methods for of red mud treatment, including both methods of low-temperature reduction at temperatures of 1050 - 1200 °C and high-temperature reduction melting, as well as utilization methods of the resulting slags. These slag utilization methods can be used for extraction of alumina, titanium and rare-earth metals, obtaining building materials such as various cements, mineral wool and flux materials for metallurgy. Methods of alkali removing, drying and agglomeration of red mud also considered. It has been shown that the best ways of bauxite residue recycling are the pyrometallurgical methods with obtaining of iron-containing product and slag for the production of building materials or metallurgical fluxes. These techniques make possible to utilize a large amount of red mud with exception of additional waste formation. This is the first part in a series of three related reviews examining the world experience of red mud recycling by various ways.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82208754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-24DOI: 10.17073/0368-0797-2018-11-884-890
V. N. Shinkin
The residual stresses in metals can lead to the defects in metals during their forming and to destruction of metal structures during their long-term operation. The resulting residual stresses during metal forming can be of plastic nature, as in the malleable metals, or caused by a slow irreversible creep at the increased temperatures and prolonged action of loads. In the viscoelastic mediums, it can be caused by the viscous parts of deformation that can accumulate when the body is deformed for a long period of time. The residual stresses also have an effect on the metals microstructure and can present inside and around the crystalline grains as the micro-residual stresses, which are called the hidden elastic stresses. Sometimes the residual stresses are called the eigenstresses by an analogy with the eigenfunctions, introduced by the mathematicians to denote the functions that correspond to the certain values (the eigenvalues) of parameters of the differential equation under the given boundary conditions. The concept of the internal stresses was proposed as a general concept for this type of stresses, created by the body itself; the term residual stresses is assigned to the case, when the internal stresses are caused by the irreversible deformation. In addition to the emergence of favorable system of residual stresses in the discs of malleable metals with a pronounced deformation hardening, there will also be a local increase in strength, provided that the Bauschinger’s effect does not negate the achieved advantages. The extreme values of residual stresses of a straight cylindrical steel rod (beam) during bending are studied below.
{"title":"Упругопластический изгиб круглого стального бруса. Сообщение 2. Остаточные напряжения","authors":"V. N. Shinkin","doi":"10.17073/0368-0797-2018-11-884-890","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-11-884-890","url":null,"abstract":"The residual stresses in metals can lead to the defects in metals during their forming and to destruction of metal structures during their long-term operation. The resulting residual stresses during metal forming can be of plastic nature, as in the malleable metals, or caused by a slow irreversible creep at the increased temperatures and prolonged action of loads. In the viscoelastic mediums, it can be caused by the viscous parts of deformation that can accumulate when the body is deformed for a long period of time. The residual stresses also have an effect on the metals microstructure and can present inside and around the crystalline grains as the micro-residual stresses, which are called the hidden elastic stresses. Sometimes the residual stresses are called the eigenstresses by an analogy with the eigenfunctions, introduced by the mathematicians to denote the functions that correspond to the certain values (the eigenvalues) of parameters of the differential equation under the given boundary conditions. The concept of the internal stresses was proposed as a general concept for this type of stresses, created by the body itself; the term residual stresses is assigned to the case, when the internal stresses are caused by the irreversible deformation. In addition to the emergence of favorable system of residual stresses in the discs of malleable metals with a pronounced deformation hardening, there will also be a local increase in strength, provided that the Bauschinger’s effect does not negate the achieved advantages. The extreme values of residual stresses of a straight cylindrical steel rod (beam) during bending are studied below.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86060855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-24DOI: 10.17073/0368-0797-2018-11-859-865
Л. И. Леушина, Игорь Олегович Леушин, С. В. Плохое, В.Б. Деев
The use of quartz for its low-temperature modification creates additional risks in the manufacture of molds in the part of their reduced crack resistance due to polymorphous transformations and in practice it often leads to cracking and even destruction of individual layers of the shell wall or the mold as a whole. Preliminary calcination of the covering material practiced in many foundries can somewhat reduce the negative consequence of dangerous polymorphic transformations of quartz. But at the same time, smooth heating of the molds to reduce the likelihood of their cracking, which is carried out in the support filler, contributes to an increase in duration of the technological process and in additional energy costs. Among the options for reducing the likelihood of cracking and the destruction of RP during their calcination, the most popular is replacement of pulverized quartz sand, as filler, with dispersed quartz sand of a polyfraction composition, disten-sillimanite, pulverized aluminosilicate, spherical corundum or fused quartz. However, all of them are quite expensive and do not meet modern challenges and resource saving requirements in foundry and metallurgical industries. In this connection, attention is drawn to the ceramic shards of shells of steel and aluminum investment casting on silica-based models. At present, the shards of spent ceramic shell molds for investment models is not used for recycling. This material is sent to the dump or used as a supporting filler of the flasks when the shells are formed therein. The conducted component chemical and phase analysis of the material has shown that in shards of ceramic shells formed after knocking out steel and aluminum castings from molds, in addition to quartz in the high-temperature phases of tridymite and cristobalite (base), there are up to 5 - 10 % of iron and iron scale and 3 - 5 % of aluminum and its oxides. The use of ceramic shell shards as a covering material excludes the repeated polymorphic quartz transformations during calcination and pouring of shapes that determine the change in volume, density, and change in types of material crystal lattices, which makes it possible to increase the fracture toughness and strength of the shells and to minimize discard of the resulting castings. Residual iron, aluminum and their oxides contribute to improving the processability of the mold. Experimental testing of the proposed recycling option in the conditions of current production has confirmed its effectiveness.
{"title":"О перспективах рециклинга боя кварцевых керамических оболочек литья по выплавляемым моделям","authors":"Л. И. Леушина, Игорь Олегович Леушин, С. В. Плохое, В.Б. Деев","doi":"10.17073/0368-0797-2018-11-859-865","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-11-859-865","url":null,"abstract":"The use of quartz for its low-temperature modification creates additional risks in the manufacture of molds in the part of their reduced crack resistance due to polymorphous transformations and in practice it often leads to cracking and even destruction of individual layers of the shell wall or the mold as a whole. Preliminary calcination of the covering material practiced in many foundries can somewhat reduce the negative consequence of dangerous polymorphic transformations of quartz. But at the same time, smooth heating of the molds to reduce the likelihood of their cracking, which is carried out in the support filler, contributes to an increase in duration of the technological process and in additional energy costs. Among the options for reducing the likelihood of cracking and the destruction of RP during their calcination, the most popular is replacement of pulverized quartz sand, as filler, with dispersed quartz sand of a polyfraction composition, disten-sillimanite, pulverized aluminosilicate, spherical corundum or fused quartz. However, all of them are quite expensive and do not meet modern challenges and resource saving requirements in foundry and metallurgical industries. In this connection, attention is drawn to the ceramic shards of shells of steel and aluminum investment casting on silica-based models. At present, the shards of spent ceramic shell molds for investment models is not used for recycling. This material is sent to the dump or used as a supporting filler of the flasks when the shells are formed therein. The conducted component chemical and phase analysis of the material has shown that in shards of ceramic shells formed after knocking out steel and aluminum castings from molds, in addition to quartz in the high-temperature phases of tridymite and cristobalite (base), there are up to 5 - 10 % of iron and iron scale and 3 - 5 % of aluminum and its oxides. The use of ceramic shell shards as a covering material excludes the repeated polymorphic quartz transformations during calcination and pouring of shapes that determine the change in volume, density, and change in types of material crystal lattices, which makes it possible to increase the fracture toughness and strength of the shells and to minimize discard of the resulting castings. Residual iron, aluminum and their oxides contribute to improving the processability of the mold. Experimental testing of the proposed recycling option in the conditions of current production has confirmed its effectiveness.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83530155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-24DOI: 10.17073/0368-0797-2018-11-907-913
A. Kudryavtsev, K. A. Okhapkin
The influence of long-term operation at 515 °C on structure and properties of 09Cr18Ni9 steel was investigated. Structure and phase composition were obtained using optical and scanning electron microscopy. The phase composition of the steel in equilibrium state was determined by thermodynamic modeling in the software package Fact-Sage. As a result of the study, it was found that during the operation at 515 °C with a duration of 195,000 h, the structure changes occurred in the 09Cr18Ni9 steel with the formation of secondary phases, initiated by the release of elements with limited solubility from the supersaturated solid solution. The following secondary precipitates in structure of the solid solution of austenite presented: Cr23C6 chromium carbide, ferrite (a), G-phase. Based on comparison of the thermodynamic modeling results and on experimental determination of the phase composition, it was established that the steel structure is in a state close to equilibrium. The mechanism of structural transformations course and sequence of the secondary phases’ formation were revealed and described. At the initial stage, chromium carbide is formed, then a-ferrite is formed near the carbides, and then G-phase is formed. Results of the tests for impact strength and static elongation have shown that the change in phase composition in process of thermal aging leads to embrittlement of the steel - a reduction in ductility and impact energy. Fractografic studies of fracture surfaces of the samples have shown that the decrease in plasticity during long-term high-temperature operation is associated with softening of the grain body and strengthening of the boundaries due to secondary precipitations of the carbide phase. As a result of this process, plastic deformation is localized in the weakened volume of the body of grain surrounded by strong boundaries. The structure evolution during prolonged heat aging has the greatest effect on impact strength. At the same time, the change in ultimate and yield stress is insignificant. The main contribution to the change in mechanical characteristics of steel is made by the secondary precipitates of the carbide phase.
{"title":"Влияние длительного теплового старения в составе теплообменного оборудования реакторной установки на быстрых нейтронах на структуру и свойства аустенитной хромоникелевой стали","authors":"A. Kudryavtsev, K. A. Okhapkin","doi":"10.17073/0368-0797-2018-11-907-913","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-11-907-913","url":null,"abstract":"The influence of long-term operation at 515 °C on structure and properties of 09Cr18Ni9 steel was investigated. Structure and phase composition were obtained using optical and scanning electron microscopy. The phase composition of the steel in equilibrium state was determined by thermodynamic modeling in the software package Fact-Sage. As a result of the study, it was found that during the operation at 515 °C with a duration of 195,000 h, the structure changes occurred in the 09Cr18Ni9 steel with the formation of secondary phases, initiated by the release of elements with limited solubility from the supersaturated solid solution. The following secondary precipitates in structure of the solid solution of austenite presented: Cr23C6 chromium carbide, ferrite (a), G-phase. Based on comparison of the thermodynamic modeling results and on experimental determination of the phase composition, it was established that the steel structure is in a state close to equilibrium. The mechanism of structural transformations course and sequence of the secondary phases’ formation were revealed and described. At the initial stage, chromium carbide is formed, then a-ferrite is formed near the carbides, and then G-phase is formed. Results of the tests for impact strength and static elongation have shown that the change in phase composition in process of thermal aging leads to embrittlement of the steel - a reduction in ductility and impact energy. Fractografic studies of fracture surfaces of the samples have shown that the decrease in plasticity during long-term high-temperature operation is associated with softening of the grain body and strengthening of the boundaries due to secondary precipitations of the carbide phase. As a result of this process, plastic deformation is localized in the weakened volume of the body of grain surrounded by strong boundaries. The structure evolution during prolonged heat aging has the greatest effect on impact strength. At the same time, the change in ultimate and yield stress is insignificant. The main contribution to the change in mechanical characteristics of steel is made by the secondary precipitates of the carbide phase.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78667706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-12-24DOI: 10.17073/0368-0797-2018-11-898-906
Александр Иванович Гусев, А. А. Усольцев, Николай Анатольевич Козырев, Н. В. Кибко, Л.П. Бащенко
Powder wire for surfacing of abrasive-wearing products of Fe - C - Si - Мп - Cr -Ni - Mo system (type A according to IIW classification) was developed and investigated. Studies in laboratory conditions were performed according to the following scheme: multilayer surfacing of the samples was carried out with preheating of plates up to 350 °C and subsequent slow cooling (after surfacing). Surfacing was made by ASAW-1250 welding tractor with manufactured cored wire in six layers on plates of 09G2S steel. Instead of amorphous carbon, carbon-fluorine-containing dust containing 21 - 46 % Al 2 O 3 ; 18 - 27 % F; 8 - 15 % Na 2 O; 0.4 - 6.0 % K 2 O; 0.7 - 2.3 % CaO; 0.5 - 2.5 % SiO 2 ; 2.1 - 3.3 % Fe 2 O 3 ; 12.5 - 30.2 % Cgen ; 0.07 - 0.90 % MnO; 0.06 -- 0.90 % MgO; 0.09 - 0.19 % S; 0.10 - 0.18 % P was introduced into the wire. The following powder materials were used as filler: iron powder PZhV1 as per GOST 9849 - 86, ferrosilicon powder FS 75 as per GOST 1415 - 93, high carbon ferrochrome powder F99A as per GOST 4757 - 91, carbon ferromanganese powder FMN 78(A) as per GOST 4755 - 91, PNK-1L5 nickel powder PNK-1L5 as per GOST 9722 - 97, ferromolybdenum powder FMo60 as per GOST 4759 - 91, ferrovanadium powder FV50U 0.6 as per GOST 27130 - 94, cobalt powder PC-1U as per GOST 9721 - 79, tungsten powder PVN as per PS 48-19-72 - 92. Studies of the deposited layer have shown that within the obtained limits, carbon, chromium, molybdenum, nickel, manganese and to a lesser extent vanadium simultaneously increase hardness of the deposited layer and reduce rate of wear of the samples. Increase in concentration of tungsten increases hardness of the deposited metal but reduces wear resistance. Low viscosity of matrix does not allow tungsten carbides to be kept on surface, as a result, wear occurs not according to the uniform surface abrasion scheme, but is reasoned by pitting high-strength carbide particles from the matrix, resulting in additional cracks formed in matrix, contributing to additional wear of matrix. Introduction of cobalt to the mixture composition does not have significant effect on hardness and abrasive wear of the deposited layer, which is associated with obtaining more viscous, but less solid matrix. In case of absence of solid particles of carbides embedded in matrix, the effect of introduction of cobalt is negative. According to the results of multivariate correlation analysis, dependences of hardness of the deposited layer and its wear resistance on mass fraction of elements included in flux-cored wires of the Fe - C - Si - Mn - Cr - Mo - Ni - V - Co system were determined.
{"title":"Разработка порошковой проволоки для наплавки деталей, работающих в условиях износа","authors":"Александр Иванович Гусев, А. А. Усольцев, Николай Анатольевич Козырев, Н. В. Кибко, Л.П. Бащенко","doi":"10.17073/0368-0797-2018-11-898-906","DOIUrl":"https://doi.org/10.17073/0368-0797-2018-11-898-906","url":null,"abstract":"Powder wire for surfacing of abrasive-wearing products of Fe - C - Si - Мп - Cr -Ni - Mo system (type A according to IIW classification) was developed and investigated. Studies in laboratory conditions were performed according to the following scheme: multilayer surfacing of the samples was carried out with preheating of plates up to 350 °C and subsequent slow cooling (after surfacing). Surfacing was made by ASAW-1250 welding tractor with manufactured cored wire in six layers on plates of 09G2S steel. Instead of amorphous carbon, carbon-fluorine-containing dust containing 21 - 46 % Al 2 O 3 ; 18 - 27 % F; 8 - 15 % Na 2 O; 0.4 - 6.0 % K 2 O; 0.7 - 2.3 % CaO; 0.5 - 2.5 % SiO 2 ; 2.1 - 3.3 % Fe 2 O 3 ; 12.5 - 30.2 % Cgen ; 0.07 - 0.90 % MnO; 0.06 -- 0.90 % MgO; 0.09 - 0.19 % S; 0.10 - 0.18 % P was introduced into the wire. The following powder materials were used as filler: iron powder PZhV1 as per GOST 9849 - 86, ferrosilicon powder FS 75 as per GOST 1415 - 93, high carbon ferrochrome powder F99A as per GOST 4757 - 91, carbon ferromanganese powder FMN 78(A) as per GOST 4755 - 91, PNK-1L5 nickel powder PNK-1L5 as per GOST 9722 - 97, ferromolybdenum powder FMo60 as per GOST 4759 - 91, ferrovanadium powder FV50U 0.6 as per GOST 27130 - 94, cobalt powder PC-1U as per GOST 9721 - 79, tungsten powder PVN as per PS 48-19-72 - 92. Studies of the deposited layer have shown that within the obtained limits, carbon, chromium, molybdenum, nickel, manganese and to a lesser extent vanadium simultaneously increase hardness of the deposited layer and reduce rate of wear of the samples. Increase in concentration of tungsten increases hardness of the deposited metal but reduces wear resistance. Low viscosity of matrix does not allow tungsten carbides to be kept on surface, as a result, wear occurs not according to the uniform surface abrasion scheme, but is reasoned by pitting high-strength carbide particles from the matrix, resulting in additional cracks formed in matrix, contributing to additional wear of matrix. Introduction of cobalt to the mixture composition does not have significant effect on hardness and abrasive wear of the deposited layer, which is associated with obtaining more viscous, but less solid matrix. In case of absence of solid particles of carbides embedded in matrix, the effect of introduction of cobalt is negative. According to the results of multivariate correlation analysis, dependences of hardness of the deposited layer and its wear resistance on mass fraction of elements included in flux-cored wires of the Fe - C - Si - Mn - Cr - Mo - Ni - V - Co system were determined.","PeriodicalId":35527,"journal":{"name":"Izvestiya Vysshikh Uchebnykh Zavedenij. Chernaya Metallurgiya","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76189328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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