Pub Date : 2024-04-11DOI: 10.24425/amm.2024.149101
M. Nabrdalik, M. Sobociński
The paper presents analysis of influence of change of physical parameters such as: temperature, friction coefficient and load, during the process of die forging. Optimization of the process effects in achieving high quality products, decreasing shaping resistance, and what follows – lower energy consumption. Temperature is the basic factor affecting the process of plastic working. Analyzing that influence in individual die fragments, allows to engineer the flow of shaped material. The QForm3D commercial program for finite element method calculations was used for numerical simulations. The paper presents multi-variant analysis of forging process with the usage of numerical simulation, which provided many valuable information concerning changes of key parameters, such as: temperature, stress and strain distribution and variations of technological parameters, as well as their mutual influence, difficult to obtain in analysis of industrial process.
{"title":"The Influence of Physical Properties of C55 Alloy on Geometry of Flow in the Process of Shaping","authors":"M. Nabrdalik, M. Sobociński","doi":"10.24425/amm.2024.149101","DOIUrl":"https://doi.org/10.24425/amm.2024.149101","url":null,"abstract":"The paper presents analysis of influence of change of physical parameters such as: temperature, friction coefficient and load, during the process of die forging. Optimization of the process effects in achieving high quality products, decreasing shaping resistance, and what follows – lower energy consumption. Temperature is the basic factor affecting the process of plastic working. Analyzing that influence in individual die fragments, allows to engineer the flow of shaped material. The QForm3D commercial program for finite element method calculations was used for numerical simulations. The paper presents multi-variant analysis of forging process with the usage of numerical simulation, which provided many valuable information concerning changes of key parameters, such as: temperature, stress and strain distribution and variations of technological parameters, as well as their mutual influence, difficult to obtain in analysis of industrial process.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140713928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-11DOI: 10.24425/amm.2024.149104
M. Trzaskalska
Unconventional injection methods include i.e. blowing injection that allows for production of moldings with a lower weight while maintaining mechanical properties of detail. Due to the fact that most polymers are dyed at the processing stage, it is important to examine the simultaneous effect of blowing and colorbatch, as well as variable processing conditions, on the functional properties of moldings made of the most popular construction material, i.e. ABS. Samples were made of ABS polymer without and with the addition of a colorbatch containing brown pigment on ABS matrix, and blowing agent. Variable processing conditions were: mold and injection temperature, holding pressure and time. Other parameters were constant. Samples were tested for basic functional properties such as color, gloss, mass, density and thickness. Moldings produced with a higher blowing agent content and a higher injection temperature were characterized by lower mass. No significant influence of processing parameters and content of colorbatch on mass of samples was found. Blowing agent has no significant impact on thickness of moldings, regardless of processing conditions. Addition of a colorbatch influenced samples’ gloss. Increase in colorbatch and blowing agent content and mold temperature allow to obtain moldings with a higher surface gloss. Colorbatch also changed color of samples – a decrease in luminance L even by about 40% and great changes in parameters “a” and slight changes in parameter “b”. It was found that blowing agent content had the greatest influence on density of moldings. Injection temperature and colorbatch, do not significantly affect density of moldings.
非常规注塑方法包括吹塑注塑，这种方法可以在保持细节机械性能的同时，生产出重量更轻的模塑件。由于大多数聚合物在加工阶段都会染色，因此有必要研究吹塑和色料以及不同加工条件对最流行的建筑材料 ABS 制成的模塑件的功能特性的影响。样品由 ABS 聚合物制成，其中不包括在 ABS 基质上添加棕色颜料的色料，也不包括发泡剂。可变的加工条件包括：模具和注塑温度、保压压力和时间。其他参数保持不变。测试样品的基本功能特性，如颜色、光泽、质量、密度和厚度。发泡剂含量越高、注塑温度越高的模塑件质量越低。没有发现加工参数和色料含量对样品质量有明显影响。无论加工条件如何，发泡剂对成型件的厚度都没有明显影响。添加色料会影响样品的光泽度。增加色料和发泡剂的含量以及模具温度可以获得表面光泽度更高的模塑件。色料还改变了样品的颜色--亮度 L 甚至降低了约 40%，参数 "a "发生了很大变化，而参数 "b "则略有变化。研究发现，发泡剂含量对成型密度的影响最大。注塑温度和色料对成型密度的影响不大。
{"title":"Addition of Modifying Agents vs Basic Functional Properties of Moldings Made of ABS","authors":"M. Trzaskalska","doi":"10.24425/amm.2024.149104","DOIUrl":"https://doi.org/10.24425/amm.2024.149104","url":null,"abstract":"Unconventional injection methods include i.e. blowing injection that allows for production of moldings with a lower weight while maintaining mechanical properties of detail. Due to the fact that most polymers are dyed at the processing stage, it is important to examine the simultaneous effect of blowing and colorbatch, as well as variable processing conditions, on the functional properties of moldings made of the most popular construction material, i.e. ABS. Samples were made of ABS polymer without and with the addition of a colorbatch containing brown pigment on ABS matrix, and blowing agent. Variable processing conditions were: mold and injection temperature, holding pressure and time. Other parameters were constant. Samples were tested for basic functional properties such as color, gloss, mass, density and thickness. Moldings produced with a higher blowing agent content and a higher injection temperature were characterized by lower mass. No significant influence of processing parameters and content of colorbatch on mass of samples was found. Blowing agent has no significant impact on thickness of moldings, regardless of processing conditions. Addition of a colorbatch influenced samples’ gloss. Increase in colorbatch and blowing agent content and mold temperature allow to obtain moldings with a higher surface gloss. Colorbatch also changed color of samples – a decrease in luminance L even by about 40% and great changes in parameters “a” and slight changes in parameter “b”. It was found that blowing agent content had the greatest influence on density of moldings. Injection temperature and colorbatch, do not significantly affect density of moldings.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140713295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-11DOI: 10.24425/amm.2024.147819
J. Garus, J. Petru, W. Sochacki, S. Garus
The study analyzed the influence of periodic and aperiodic stiffness distribution for the four-element Bernoulli-Euler beam on the first two eigenfrequencies and the dynamic stability of the system. The influence of increasing the ratio of cross-sections of the analyzed elements was also analyzed. Significant differences were found in eigenfrequencies and dynamic stability. Using the variational Hamilton principle, the equation of motion was derived, on the basis of which the values of the eigenfrequencies were determined, and the transformation into the form of the Mathieu equation made it possible to determine the dynamic stability for the analyzed structures.
{"title":"Dynamic Stability of the Periodic and Aperiodic Structures of the Bernoulli-Euler Beams","authors":"J. Garus, J. Petru, W. Sochacki, S. Garus","doi":"10.24425/amm.2024.147819","DOIUrl":"https://doi.org/10.24425/amm.2024.147819","url":null,"abstract":"The study analyzed the influence of periodic and aperiodic stiffness distribution for the four-element Bernoulli-Euler beam on the first two eigenfrequencies and the dynamic stability of the system. The influence of increasing the ratio of cross-sections of the analyzed elements was also analyzed. Significant differences were found in eigenfrequencies and dynamic stability. Using the variational Hamilton principle, the equation of motion was derived, on the basis of which the values of the eigenfrequencies were determined, and the transformation into the form of the Mathieu equation made it possible to determine the dynamic stability for the analyzed structures.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140712871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-11DOI: 10.24425/amm.2024.149105
K. Ścibisz, J. Krawczyk
Improvement of magnetic properties of electrical steel can be achieved by reduction the size of magnetic domains. The application of local stresses through laser scribing leads to reduced core losses. In order to determine the effect of laser refinement conditions of magnetic domains on the properties of the soft magnetic material, four samples with a thickness 0.23 mm were refined. The refinement of each sample was carried out using different line energies of the laser beam. Estimation of the magnetic domain size was performed using the Jeffries method, the magnetic viewer was used to reveal the domain structure. The measurement of the magnetic properties was performed at a frequency of 50 Hz and an induction of 1.5 T. The analyzed results presented in this work indicate impact of laser refining on magnetic properties of grain oriented electrical steel depending on used laser beam energy.
通过减小磁畴的尺寸可以改善电工钢的磁性能。通过激光划线施加局部应力可降低磁芯损耗。为了确定激光细化磁畴的条件对软磁材料特性的影响，我们细化了四个厚度为 0.23 毫米的样品。对每个样品的细化都使用了不同线能量的激光束。使用杰弗里斯法估算磁畴尺寸，使用磁性观察器揭示磁畴结构。磁性能的测量是在频率为 50 Hz、磁感应强度为 1.5 T 的条件下进行的。分析结果表明，激光细化对晶粒取向电工钢磁性能的影响取决于所使用的激光束能量。
{"title":"Magnetic Properties of Fe-Si Electrical Steel after Laser Scribing","authors":"K. Ścibisz, J. Krawczyk","doi":"10.24425/amm.2024.149105","DOIUrl":"https://doi.org/10.24425/amm.2024.149105","url":null,"abstract":"Improvement of magnetic properties of electrical steel can be achieved by reduction the size of magnetic domains. The application of local stresses through laser scribing leads to reduced core losses. In order to determine the effect of laser refinement conditions of magnetic domains on the properties of the soft magnetic material, four samples with a thickness 0.23 mm were refined. The refinement of each sample was carried out using different line energies of the laser beam. Estimation of the magnetic domain size was performed using the Jeffries method, the magnetic viewer was used to reveal the domain structure. The measurement of the magnetic properties was performed at a frequency of 50 Hz and an induction of 1.5 T. The analyzed results presented in this work indicate impact of laser refining on magnetic properties of grain oriented electrical steel depending on used laser beam energy.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140715938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-11DOI: 10.24425/amm.2024.147815
D. Woźniak, S. Żak
The required rail straightness is achieved by straightening with roller straighteners. The consequence of the straightening operation is the introduction of residual stresses to the straightened rail. An excessive level of residual stresses accumulated in the rail during use in the track may lead to its damage or fracture. ArcelorMittal Poland S.A., in cooperation with Łukasiewicz Research Network – Institute for Ferrous Metallurgy, carried out a research project (POI R.01.02.00-00-0167/16) the aim of which was to reduce residual stresses in railway rails by changing the technological parameters of the straightening process. The results of the presented study relate to rails 60E1 and 60E2. The study includes the measurement, testing, calculations and analyses of the obtained results. The conducted research indicates the possibility of obtaining a low level of residual stress in the rails for a system consisting of a 7-roller vertical straightener and a 9-roller horizontal straightener by changing the roller settings, the shape of the rollers, the shape of the rail foot and its curvature.
{"title":"Influence of Vertical Straightener Roller Shape on Residual Stress Level in Railway Rails","authors":"D. Woźniak, S. Żak","doi":"10.24425/amm.2024.147815","DOIUrl":"https://doi.org/10.24425/amm.2024.147815","url":null,"abstract":"The required rail straightness is achieved by straightening with roller straighteners. The consequence of the straightening operation is the introduction of residual stresses to the straightened rail. An excessive level of residual stresses accumulated in the rail during use in the track may lead to its damage or fracture. ArcelorMittal Poland S.A., in cooperation with Łukasiewicz Research Network – Institute for Ferrous Metallurgy, carried out a research project (POI R.01.02.00-00-0167/16) the aim of which was to reduce residual stresses in railway rails by changing the technological parameters of the straightening process. The results of the presented study relate to rails 60E1 and 60E2. The study includes the measurement, testing, calculations and analyses of the obtained results. The conducted research indicates the possibility of obtaining a low level of residual stress in the rails for a system consisting of a 7-roller vertical straightener and a 9-roller horizontal straightener by changing the roller settings, the shape of the rollers, the shape of the rail foot and its curvature.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140716041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-11DOI: 10.24425/amm.2024.149099
J. Nabiałek, T. Jaruga
The results of computer modelling of an injection moulding process with microcellular foaming (MuCell®) were presented in this work. The process is based on the dissolving nitrogen in a liquid polymer which is possible when nitrogen is in supercritical fluid state (SCF). After pressure drop of the melt in the injection mould the intensive nucleation of pores occurs and, as the result, the material with high concentration of small pores is created. The pores obtained in this way are of much smaller size than in a conventional foaming process. The pore size in the cross-section of an exemplary injection moulded part was calculated in the computer modelling and compared to the results of microscopical investigation made on the real injection moulded part. It was found that the size of the pores depends on the flow length inside the injection mould and on the position in the part’s cross-section.
{"title":"Numerical Modelling of Microcellular Foaming Injection Moulding","authors":"J. Nabiałek, T. Jaruga","doi":"10.24425/amm.2024.149099","DOIUrl":"https://doi.org/10.24425/amm.2024.149099","url":null,"abstract":"The results of computer modelling of an injection moulding process with microcellular foaming (MuCell®) were presented in this work. The process is based on the dissolving nitrogen in a liquid polymer which is possible when nitrogen is in supercritical fluid state (SCF). After pressure drop of the melt in the injection mould the intensive nucleation of pores occurs and, as the result, the material with high concentration of small pores is created. The pores obtained in this way are of much smaller size than in a conventional foaming process. The pore size in the cross-section of an exemplary injection moulded part was calculated in the computer modelling and compared to the results of microscopical investigation made on the real injection moulded part. It was found that the size of the pores depends on the flow length inside the injection mould and on the position in the part’s cross-section.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140715295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-11DOI: 10.24425/amm.2024.147821
L. A. Sofri, D. Ganesan, M. M. A. B. Abdullah, Chee-Ming Chan, M. Osman, J. Garus, S. Garus
Porous asphalt has excellent permeability and larger air voids. Due to the low stability strength of asphalt binder with aggregates, Malaysia uses porous asphalt roads for lightweight vehicle road transportation. Numerous studies indicate utilizing Recycled High-Density Polyethylene in porous asphalt road surface. As a result, it was utilised as an additional binder material to enhance the asphalt binder. The main purpose of this study is to investigate the stability of modified porous asphalt samples and evaluate the optimum percentage of HDPE plastic waste from 3%, 6% and 9%. The aggregates, asphalt properties, Marshall Parameters and waster absorption test are in comply with JKR Standard and PWD 2008. At 3% of plastic addition has improved the stability of porous asphalt specimens. Adding plastic waste as a binder helps strengthen asphalt binding.
{"title":"The Effect of Recycled High-Density Polyethylene (HDPE) as an Additional Binder in Porous Asphalt Pavement","authors":"L. A. Sofri, D. Ganesan, M. M. A. B. Abdullah, Chee-Ming Chan, M. Osman, J. Garus, S. Garus","doi":"10.24425/amm.2024.147821","DOIUrl":"https://doi.org/10.24425/amm.2024.147821","url":null,"abstract":"Porous asphalt has excellent permeability and larger air voids. Due to the low stability strength of asphalt binder with aggregates, Malaysia uses porous asphalt roads for lightweight vehicle road transportation. Numerous studies indicate utilizing Recycled High-Density Polyethylene in porous asphalt road surface. As a result, it was utilised as an additional binder material to enhance the asphalt binder. The main purpose of this study is to investigate the stability of modified porous asphalt samples and evaluate the optimum percentage of HDPE plastic waste from 3%, 6% and 9%. The aggregates, asphalt properties, Marshall Parameters and waster absorption test are in comply with JKR Standard and PWD 2008. At 3% of plastic addition has improved the stability of porous asphalt specimens. Adding plastic waste as a binder helps strengthen asphalt binding.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140714074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-11DOI: 10.24425/amm.2024.147822
H. M. Hanafi, K. Muthusamy, W. A. Saffuan, A. Budiea, A. Kusbiantoro, M. Nabilla, A. Rafiza, K. Błoch
Escalating quantity of industrial by-products generated, including oil palm shell (OPS) and palm oil fuel ash (POFA ) of the palm oil industries, has been a concern to many analysts. They are mostly disposed off as wastes that would heavily impact the environment quality. Therefore, this paper aimed to investigate the possibility of consuming these wastes by using OPS and POFA as replacement materials for fine aggregates in the concrete mixture. The mixtures were prepared by integrating unground palm oil fuel ash of 0%, 10%, and 20% (by weight of sand) to produce lightweight concrete. The experiments observed the mechanical performance of these specimens for 180 curing days. The results show the enhancement of concrete strength relative to the control mixture by using 10% of ash. This is owing to void filling mechanism and product of pozzolanic reaction due to the fine particles of the ash.
{"title":"Mechanical Properties of Lightweight Aggregate Concrete Containing Unground Palm Oil Fuel Ash as Partial Sand Replaceme","authors":"H. M. Hanafi, K. Muthusamy, W. A. Saffuan, A. Budiea, A. Kusbiantoro, M. Nabilla, A. Rafiza, K. Błoch","doi":"10.24425/amm.2024.147822","DOIUrl":"https://doi.org/10.24425/amm.2024.147822","url":null,"abstract":"Escalating quantity of industrial by-products generated, including oil palm shell (OPS) and palm oil fuel ash (POFA ) of the palm oil industries, has been a concern to many analysts. They are mostly disposed off as wastes that would heavily impact the environment quality. Therefore, this paper aimed to investigate the possibility of consuming these wastes by using OPS and POFA as replacement materials for fine aggregates in the concrete mixture. The mixtures were prepared by integrating unground palm oil fuel ash of 0%, 10%, and 20% (by weight of sand) to produce lightweight concrete. The experiments observed the mechanical performance of these specimens for 180 curing days. The results show the enhancement of concrete strength relative to the control mixture by using 10% of ash. This is owing to void filling mechanism and product of pozzolanic reaction due to the fine particles of the ash.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140715758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-11DOI: 10.24425/amm.2024.147809
Hao Xu, R. Gou, Min Yu, Wen-Jiao Dan, Nian Wang
In order to reveal the non-uniform distribution of grain size in thick direction for engineering heavy plate, microstructure of 40 mm-thick Q345 steel was observed and measured under different short-term high temperature environments formed by fire. Moreover, the influence of the short-term high temperature environment was revealed on the distribution of ferrite grain size in the Q345 steel. Under different fire service environments, there was a log-normal distribution relationship between the distribution parameter Nf (number of ferrite grains) and df (average grain diameter), as well as ρAf (area fraction density) and df, at different positions along the thickness direction. However, the statistical results are greatly affected by the length of the statistical interval. When df is about 4 to 6 times the length of the statistical interval, the statistical accuracy is higher. By using nonlinear fitting method, multiple non-uniform distribution empirical models including Nf-df empirical formulas and ρAf-df empirical formulas were established at different positions along thick direction under various fire environments. Furthermore, the interrelationships between fire temperature T and Nf , T and ρAf , fire duration t and Nf , t and ρAf were revealed, respectively.
{"title":"The Influence of Short-Term High Temperature Environment on the Non-Uniform Distribution of Ferrite Grain Size in 40 mm-thick Q345 Steel","authors":"Hao Xu, R. Gou, Min Yu, Wen-Jiao Dan, Nian Wang","doi":"10.24425/amm.2024.147809","DOIUrl":"https://doi.org/10.24425/amm.2024.147809","url":null,"abstract":"In order to reveal the non-uniform distribution of grain size in thick direction for engineering heavy plate, microstructure of 40 mm-thick Q345 steel was observed and measured under different short-term high temperature environments formed by fire. Moreover, the influence of the short-term high temperature environment was revealed on the distribution of ferrite grain size in the Q345 steel. Under different fire service environments, there was a log-normal distribution relationship between the distribution parameter Nf (number of ferrite grains) and df (average grain diameter), as well as ρAf (area fraction density) and df, at different positions along the thickness direction. However, the statistical results are greatly affected by the length of the statistical interval. When df is about 4 to 6 times the length of the statistical interval, the statistical accuracy is higher. By using nonlinear fitting method, multiple non-uniform distribution empirical models including Nf-df empirical formulas and ρAf-df empirical formulas were established at different positions along thick direction under various fire environments. Furthermore, the interrelationships between fire temperature T and Nf , T and ρAf , fire duration t and Nf , t and ρAf were revealed, respectively.","PeriodicalId":8304,"journal":{"name":"Archives of Metallurgy and Materials","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140715994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-11DOI: 10.24425/amm.2024.147814
D. Madyira, T. O. Babarinde
Synthetic refrigerants are being phased out gradually in accordance with international environmental protection protocols because of global warming and ozone layer depletion. Adopting R290/R600 refrigerant, an environmentally friendly refrigerant, to replace R134a, a high global warming potential refrigerant, provides one of the solutions. In this study, exergy analysis of R134a and TiO2 suspended with lubricant and R290/R600 with a composition of 60% R290 and 40% R600 (60:40) was investigated in vapour compression system (VCRS) using R290/ R600 in TiO2 nanomixture lubricant and compared with R134a and R290/ R600 in pure lubricant. At the inlets and outlets, the main components of the VCRS are connected to temperature and pressure sensors to measure the inlet and outlet temperatures and pressures. The results obtained were used to analyses the exergy losses at various VCRS components (compressor, condenser, evaporator, expansion valve) were investigated to determine the refrigerator’s total exergy destruction (E·xdest.Total) and efficiency (ηex). The E·xdest.Total of R290/R600 in pure lubricant and R290/R600 TiO2 nanomixture lubricant was reduced by 26.9% and 42.3%, respectively, and system ηex increased by 27.7% and 38.9% respectively when compared to R134a in the system. Hence, TiO2 suspended with R290/R600 is potential a substitute for R134a.
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