Guomin Han, Hongbo Li, Yujin Liu, J. Zhang, N. Kong, Zhiyuan Hu, Lei Liu
In tandem cold rolling, the control of the temperature of high-grade non-oriented silicon steel is a difficult problem for its large deformation resistance and the preheating procedure before rolling. And it is complicated to calculate the total temperature rise of rolling deformation zone due to the comprehensive influence of the plastic deformation heat, the friction heat and the contact heat loss. So, to precisely calculate the total temperature rise, firstly, based on the four classical cold rolling force formulas, the initial total temperature rise calculation models are established correspondingly by theoretically analyzing the temperature rise of deformation heat, the temperature rise of friction heat and the temperature drop of contact heat loss; then, the model based on the improved Lian rolling force formula is adopted, which leads to calculated best matching the measured temperature; finally, considering the complex formula calculation of the initial model, based on the influences of different rolling parameters on the total temperature rise, a simplified model for convenient calculation is proposed by the nonlinear regression analysis of the initial model calculation results and main rolling parameters, which is convenient for the actual application by the field technicians.
{"title":"A simplified mathematical model for total temperature rise calculation in non-oriented silicon steel cold rolling deformation zone","authors":"Guomin Han, Hongbo Li, Yujin Liu, J. Zhang, N. Kong, Zhiyuan Hu, Lei Liu","doi":"10.1051/metal/2021095","DOIUrl":"https://doi.org/10.1051/metal/2021095","url":null,"abstract":"In tandem cold rolling, the control of the temperature of high-grade non-oriented silicon steel is a difficult problem for its large deformation resistance and the preheating procedure before rolling. And it is complicated to calculate the total temperature rise of rolling deformation zone due to the comprehensive influence of the plastic deformation heat, the friction heat and the contact heat loss. So, to precisely calculate the total temperature rise, firstly, based on the four classical cold rolling force formulas, the initial total temperature rise calculation models are established correspondingly by theoretically analyzing the temperature rise of deformation heat, the temperature rise of friction heat and the temperature drop of contact heat loss; then, the model based on the improved Lian rolling force formula is adopted, which leads to calculated best matching the measured temperature; finally, considering the complex formula calculation of the initial model, based on the influences of different rolling parameters on the total temperature rise, a simplified model for convenient calculation is proposed by the nonlinear regression analysis of the initial model calculation results and main rolling parameters, which is convenient for the actual application by the field technicians.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"4 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90960995","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}
Hebin Wang, D. Hong, L. Hou, Li Shen, P. Ou, LiFang Qiu, Zhi-gang Wang, Hong-jin Zhao
The microstructure and properties of niobium-containing AISI M3:2 high speed steels (HSSs) fabricated by spray forming and traditional casting have been investigated. The results show that fine and uniformly-distributed grains without macrosegregation appeared in the as-deposited HSSs that differ from those of as-cast HSSs. Nb mostly appears in primary MC carbides, whereas it contributes less to the formation of M6C carbides. The high stabilization of Nb-rich MC carbides can pin the grain boundaries during high-temperature austenitizing process, thus conferring a fine grains and raising the content of dissolved alloying elements. Enhanced precipitation strengthening and fine dispersion of NbC carbides throughout the matrix contribute to the high hardness and red hardness of Nb-containing HSS.
{"title":"Effect of niobium and austenitizing temperature on the microstructures and properties of spray-deposited AISI M3:2 high speed steel","authors":"Hebin Wang, D. Hong, L. Hou, Li Shen, P. Ou, LiFang Qiu, Zhi-gang Wang, Hong-jin Zhao","doi":"10.1051/metal/2021097","DOIUrl":"https://doi.org/10.1051/metal/2021097","url":null,"abstract":"The microstructure and properties of niobium-containing AISI M3:2 high speed steels (HSSs) fabricated by spray forming and traditional casting have been investigated. The results show that fine and uniformly-distributed grains without macrosegregation appeared in the as-deposited HSSs that differ from those of as-cast HSSs. Nb mostly appears in primary MC carbides, whereas it contributes less to the formation of M6C carbides. The high stabilization of Nb-rich MC carbides can pin the grain boundaries during high-temperature austenitizing process, thus conferring a fine grains and raising the content of dissolved alloying elements. Enhanced precipitation strengthening and fine dispersion of NbC carbides throughout the matrix contribute to the high hardness and red hardness of Nb-containing HSS.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86379320","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}
The significant impact of ultra-rapid heating continuous annealing on microstructure and mechanical properties of Al substituted Si dual phase steel under hot-dip galvanized process was studied. The heating rate of 300 °C/s, and different annealing temperatures in the range of 750 °C to 810 °C were explored. The study indicated that the yield and tensile strengths are increased with the increase of intercritical annealing temperature during rapid heating continuous annealing. When the annealing temperature was 780 °C, the steel exhibited good comprehensive properties with yield strength of 574.9 MPa, tensile strength up to 1009 MPa, total elongation of 18.5%. This is attributed to refined microstructure, appropriate proportion of phases, high density of dislocations and finely distributed NbC precipitates. Furthermore, the variations in strength, elongation and strain-hardening behavior of the steel with thermomechanical parameters and the inherent mechanism for strengthening were further discussed in relation to the microstructural features.
{"title":"Significant impact of intercritical annealing temperature on microstructure and mechanical properties of Al substituted Si dual phase steel under ultra-rapid heating","authors":"Y. Deng, R. Misra","doi":"10.1051/metal/2021051","DOIUrl":"https://doi.org/10.1051/metal/2021051","url":null,"abstract":"The significant impact of ultra-rapid heating continuous annealing on microstructure and mechanical properties of Al substituted Si dual phase steel under hot-dip galvanized process was studied. The heating rate of 300 °C/s, and different annealing temperatures in the range of 750 °C to 810 °C were explored. The study indicated that the yield and tensile strengths are increased with the increase of intercritical annealing temperature during rapid heating continuous annealing. When the annealing temperature was 780 °C, the steel exhibited good comprehensive properties with yield strength of 574.9 MPa, tensile strength up to 1009 MPa, total elongation of 18.5%. This is attributed to refined microstructure, appropriate proportion of phases, high density of dislocations and finely distributed NbC precipitates. Furthermore, the variations in strength, elongation and strain-hardening behavior of the steel with thermomechanical parameters and the inherent mechanism for strengthening were further discussed in relation to the microstructural features.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"4 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76875428","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}
To destabilize as-cast microstructure of 20 wt.% chromium white iron, cyclic annealing involving repeated austenitization for short duration of 0.6 h at 900, 950, 1000, 1050 and 1100 °C followed by forced air cooling is conducted as an alternative to continuous annealing requiring austenitization for longer period of 4–6 h at the said temperatures followed by furnace cooling. Continuous austenitization destabilizes the austenite matrix through precipitation of secondary carbides and transforms the alloy depleted austenite to pearlite on furnace cooling, thereby reducing the as-cast hardness from HV 669 to HV466. In contrast, repeated austenitization not only destabilizes the austenite matrix through precipitation of secondary carbides followed by its transformation to martensite on forced air cooling, but also causes disintegration of longer eutectic carbides to shorter segments with subsequent increase in hardness to as high as HV 890. Notched impact toughness after both continuous and cyclic annealing remains uniformly at 12.0 J as compared to as-cast value of 6.0 J. Besides, an unexpected rise in abrasive wear resistance after cyclic annealing treatment makes the alloy superior than that obtained by continuous annealing treatment as practiced in industries.
{"title":"Cyclic annealing versus continuous annealing of 20 wt.% chromium white cast iron","authors":"S. S. Mandal, D. Mondal, K. Ghosh","doi":"10.1051/metal/2021044","DOIUrl":"https://doi.org/10.1051/metal/2021044","url":null,"abstract":"To destabilize as-cast microstructure of 20 wt.% chromium white iron, cyclic annealing involving repeated austenitization for short duration of 0.6 h at 900, 950, 1000, 1050 and 1100 °C followed by forced air cooling is conducted as an alternative to continuous annealing requiring austenitization for longer period of 4–6 h at the said temperatures followed by furnace cooling. Continuous austenitization destabilizes the austenite matrix through precipitation of secondary carbides and transforms the alloy depleted austenite to pearlite on furnace cooling, thereby reducing the as-cast hardness from HV 669 to HV466. In contrast, repeated austenitization not only destabilizes the austenite matrix through precipitation of secondary carbides followed by its transformation to martensite on forced air cooling, but also causes disintegration of longer eutectic carbides to shorter segments with subsequent increase in hardness to as high as HV 890. Notched impact toughness after both continuous and cyclic annealing remains uniformly at 12.0 J as compared to as-cast value of 6.0 J. Besides, an unexpected rise in abrasive wear resistance after cyclic annealing treatment makes the alloy superior than that obtained by continuous annealing treatment as practiced in industries.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"232 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77075718","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}
The particle distribution in pre-reduction rotary kiln directly affects the reduction process of iron ore, and in-depth understanding of the mixing behavior is helpful to improve the product quality and productivity. The present work focused on the mixed dynamics of multi-component and multi-size systems in rotary kiln using discrete element method (DEM). We first confirmed that the final particle distribution and mixing degree are independent of the initial particle distribution, and then further discussed the influence of the key operating parameters such as rotating speed, average size ratio and filling degree on mixing behavior. The size segregation pattern of three components shows that the large particles segregated to the outer region, while the small particles were concentrated in the core region, forming an annular distribution with different particle sizes. Furthermore, the results also indicate that the rotational speed and fill degree show strong influence on the mixing time and have little influence on the mixing quality. Conversely, the average size ratio significantly affects on the mixing quality. The particle segregation is suppressed and the coal and iron ore particles are well mixed together for the whole bed when the average size of coal particles is smaller than that of iron ore particle. The findings of this work provide a reference for controlling and optimizing the particle mixing process in pre-reduction rotary kiln.
{"title":"Analyses of multi-size particle mixing behavior in an ore pre-reduction rotary kiln by discrete element method","authors":"Chenghong Liu, Xueyong Ding","doi":"10.1051/metal/2021038","DOIUrl":"https://doi.org/10.1051/metal/2021038","url":null,"abstract":"The particle distribution in pre-reduction rotary kiln directly affects the reduction process of iron ore, and in-depth understanding of the mixing behavior is helpful to improve the product quality and productivity. The present work focused on the mixed dynamics of multi-component and multi-size systems in rotary kiln using discrete element method (DEM). We first confirmed that the final particle distribution and mixing degree are independent of the initial particle distribution, and then further discussed the influence of the key operating parameters such as rotating speed, average size ratio and filling degree on mixing behavior. The size segregation pattern of three components shows that the large particles segregated to the outer region, while the small particles were concentrated in the core region, forming an annular distribution with different particle sizes. Furthermore, the results also indicate that the rotational speed and fill degree show strong influence on the mixing time and have little influence on the mixing quality. Conversely, the average size ratio significantly affects on the mixing quality. The particle segregation is suppressed and the coal and iron ore particles are well mixed together for the whole bed when the average size of coal particles is smaller than that of iron ore particle. The findings of this work provide a reference for controlling and optimizing the particle mixing process in pre-reduction rotary kiln.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"22 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90651273","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}
During the process of production and refining of industrial silicon, the discharged slag usually contains more than 15 mass% of metallic silicon. However, the separation of silicon from slag is very difficult due to the close density of silicon and slag as well as the high viscosity of slag, which results in the waste of resources. In the present work, the effect of Na2O addition on the separation of silicon from slag is investigated in detail. It is found that the optimum separation condition of slag and silicon is 1723 K reacting for 60 min by adding 10 mass% Na2O to the slag. Viscosity and density are two important factors affecting the separation effect of silicon from slag. The addition of Na2O reduces the viscosity of slag and promotes the separation of silicon from slag. Even if the addition of Na2O will decrease the density of slag which is detrimental to the separation of silicon, the density variation is not the determining factor affecting the separation relative to viscosity. The separation and extraction of metallic silicon from silicon slag is of great significance for improving utilization of resources and reducing environmental pollution.
{"title":"Study on the separation of silicon from refining slag of industrial silicon","authors":"Yong Hou, Guo-hua Zhang, K. Chou","doi":"10.1051/metal/2021036","DOIUrl":"https://doi.org/10.1051/metal/2021036","url":null,"abstract":"During the process of production and refining of industrial silicon, the discharged slag usually contains more than 15 mass% of metallic silicon. However, the separation of silicon from slag is very difficult due to the close density of silicon and slag as well as the high viscosity of slag, which results in the waste of resources. In the present work, the effect of Na2O addition on the separation of silicon from slag is investigated in detail. It is found that the optimum separation condition of slag and silicon is 1723 K reacting for 60 min by adding 10 mass% Na2O to the slag. Viscosity and density are two important factors affecting the separation effect of silicon from slag. The addition of Na2O reduces the viscosity of slag and promotes the separation of silicon from slag. Even if the addition of Na2O will decrease the density of slag which is detrimental to the separation of silicon, the density variation is not the determining factor affecting the separation relative to viscosity. The separation and extraction of metallic silicon from silicon slag is of great significance for improving utilization of resources and reducing environmental pollution.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"15 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89147529","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}
This paper investigates a comparison study of microstructure, texture and mechanical properties between two 6xxx aluminum alloys through microstructure, texture characterization and tensile test. The results show that they exhibit different microstructure, texture and mechanical properties. In comparison with the alloy sheet with a low weight ratio of Mg to Si (Si-excess), the alloy sheet with a higher weight ratio of Mg to Si (Mg-excess) and additional Zn possesses the finer as-casting and solution treated equiaxed grain structure, less particles with larger size before solution treatment, weaker recrystallization texture mainly including Cube {001} orientation and weaker mechanical properties. The low weight ratio of Mg to Si corresponds to slightly higher yield strength and ultimate tensile strength, but much higher plastic strain ration r , work hardening exponent n values and elongation. Interestingly, Portevin-Le Chatelier (PLC) effect is very prevailed in the alloy sheet with a higher weight ratio of Mg to Si and additional Zn, which is responsible for the low elongation and r value. The alloy containing a low weight ratio of Mg to Si may be beneficial to improve comprehensive mechanical property.
{"title":"A comparison study of microstructure, texture and mechanical properties between two 6xxx aluminum alloys","authors":"Xiaofeng Wang, Hong Liu, Xiaobo Tang","doi":"10.1051/METAL/2021013","DOIUrl":"https://doi.org/10.1051/METAL/2021013","url":null,"abstract":"This paper investigates a comparison study of microstructure, texture and mechanical properties between two 6xxx aluminum alloys through microstructure, texture characterization and tensile test. The results show that they exhibit different microstructure, texture and mechanical properties. In comparison with the alloy sheet with a low weight ratio of Mg to Si (Si-excess), the alloy sheet with a higher weight ratio of Mg to Si (Mg-excess) and additional Zn possesses the finer as-casting and solution treated equiaxed grain structure, less particles with larger size before solution treatment, weaker recrystallization texture mainly including Cube {001} orientation and weaker mechanical properties. The low weight ratio of Mg to Si corresponds to slightly higher yield strength and ultimate tensile strength, but much higher plastic strain ration r , work hardening exponent n values and elongation. Interestingly, Portevin-Le Chatelier (PLC) effect is very prevailed in the alloy sheet with a higher weight ratio of Mg to Si and additional Zn, which is responsible for the low elongation and r value. The alloy containing a low weight ratio of Mg to Si may be beneficial to improve comprehensive mechanical property.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"4 1","pages":"211"},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89660746","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}
Yu-long Liu, D. Ding, Chen Wenguang, N. Hu, Lingling Wu, Lin Hu, Qiucai Zhang, Zhijun Zhang, Feng Li, Xue Xilong, Zhaopeng Li, Guicheng He, Qing Yu
The relationship between energy input and particle size of ore samples after crushing and effect of microwave pretreatment on impact crushing of lead-zinc ore were studied by drop weight impact test. The results showed that the lead-zinc ore became softer and had higher degree of crushing after microwave pretreatment. Compared with continuous microwave pretreatment, pulsed microwave pretreatment could improve the drop weight impact crushing efficiency of lead-zinc ore. When the specific comminution energy were 5 kW h/t, 10 kW h/t respectively, the crushing characteristic parameters t10 were 60.42% and 67.46% respectively by continuous microwave. But the values of t10 were increased to 68.64% and 75.88% respectively after pulsed microwave radiation under same microwave power and time. In addition, water quenching could more promote the impact crushing efficiency of lead-zinc ore after microwave irradiation.
{"title":"The effect of microwave pretreatment on impact crushing of lead-zinc ore","authors":"Yu-long Liu, D. Ding, Chen Wenguang, N. Hu, Lingling Wu, Lin Hu, Qiucai Zhang, Zhijun Zhang, Feng Li, Xue Xilong, Zhaopeng Li, Guicheng He, Qing Yu","doi":"10.1051/metal/2021055","DOIUrl":"https://doi.org/10.1051/metal/2021055","url":null,"abstract":"The relationship between energy input and particle size of ore samples after crushing and effect of microwave pretreatment on impact crushing of lead-zinc ore were studied by drop weight impact test. The results showed that the lead-zinc ore became softer and had higher degree of crushing after microwave pretreatment. Compared with continuous microwave pretreatment, pulsed microwave pretreatment could improve the drop weight impact crushing efficiency of lead-zinc ore. When the specific comminution energy were 5 kW h/t, 10 kW h/t respectively, the crushing characteristic parameters t10 were 60.42% and 67.46% respectively by continuous microwave. But the values of t10 were increased to 68.64% and 75.88% respectively after pulsed microwave radiation under same microwave power and time. In addition, water quenching could more promote the impact crushing efficiency of lead-zinc ore after microwave irradiation.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"64 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90856736","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}
This study has investigated the effect of tool offset on the mechanical behavior and microstructure of dissimilar copper and brass joints by friction stir welding (FSW). In this regard, the FSW method was used for joint with three different tool offset positions, namely center line (no offset), the copper side, and the brass alloy side. Microstructure and fracture surfaces of the specimens were examined by optical (OM) and scanning electron microscopies (SEM), respectively. Tensile, micro-hardness and bending tests were also utilized to evaluate the joints mechanical behavior. The results showed that an onion ring-shaped zone was formed with the tool offset towards the copper side, but this zone was not observed with the tool offset towards the brass alloy side. In addition, compared with the tool without offset, the tensile strength with the tool offset to copper side of 1 mm (Cu+1) increased by 33.33% and with the tool offset to brass alloy side of 1 mm (Brass+1) increased by 57.47%. The results of bending test showed that in the Brass+1 specimen, bending strength increased by approximately 5% compared with the specimen without offset. Finally, it was found that the best mechanical and microstructural properties were obtained by the tool offset of 1 mm towards the brass alloy side.
研究了刀具偏移量对异种铜黄铜搅拌摩擦焊接接头力学行为和组织的影响。为此，采用FSW方法对三种不同刀具偏移位置的连接进行了加工，即中心线(无偏移)、铜侧和黄铜合金侧。采用光学显微镜(OM)和扫描电镜(SEM)对试样的显微组织和断口形貌进行了观察。利用拉伸、显微硬度和弯曲试验对接头的力学性能进行了评价。结果表明:刀具向铜侧偏置时形成了一个洋葱环区，而刀具向黄铜合金侧偏置时则没有形成洋葱环区。此外，与未偏置刀具相比，刀具偏置铜侧1 mm (Cu+1)时抗拉强度提高了33.33%，刀具偏置黄铜合金侧1 mm (brass +1)时抗拉强度提高了57.47%。弯曲试验结果表明，在黄铜+1试样中，弯曲强度比没有偏移的试样提高了约5%。结果表明，当刀具向黄铜合金侧偏移1 mm时，合金的力学性能和显微组织性能最佳。
{"title":"Effect of tool offset on microstructure and mechanical properties of dissimilar copper-brass friction stir welding","authors":"H. Sadeghi, K. Amini, F. Gharavi","doi":"10.1051/METAL/2021029","DOIUrl":"https://doi.org/10.1051/METAL/2021029","url":null,"abstract":"This study has investigated the effect of tool offset on the mechanical behavior and microstructure of dissimilar copper and brass joints by friction stir welding (FSW). In this regard, the FSW method was used for joint with three different tool offset positions, namely center line (no offset), the copper side, and the brass alloy side. Microstructure and fracture surfaces of the specimens were examined by optical (OM) and scanning electron microscopies (SEM), respectively. Tensile, micro-hardness and bending tests were also utilized to evaluate the joints mechanical behavior. The results showed that an onion ring-shaped zone was formed with the tool offset towards the copper side, but this zone was not observed with the tool offset towards the brass alloy side. In addition, compared with the tool without offset, the tensile strength with the tool offset to copper side of 1 mm (Cu+1) increased by 33.33% and with the tool offset to brass alloy side of 1 mm (Brass+1) increased by 57.47%. The results of bending test showed that in the Brass+1 specimen, bending strength increased by approximately 5% compared with the specimen without offset. Finally, it was found that the best mechanical and microstructural properties were obtained by the tool offset of 1 mm towards the brass alloy side.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"118 1","pages":"307"},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86991365","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}
In this study, the effect of mechanical soft reduction on carbon segregation in the continuous casting of 300 × 400 mm 42CrMo alloy structural steel blooms was comparatively investigated by adjusting the casting speed, which was systematically optimized through numerical simulation. When the casting speed is 0.60 m · min−1, during the soft reduction process, the central solidification structure of the bloom becomes dense, and carbon segregation is improved. Moreover, the distribution of carbon in the samples before and after rolling was analyzed. Combined with the soft reduction process, the uniformity of carbon across the cross section of the bloom /bar distinctly improved for casting speeds of 0.50 m · min−1, 0.55 m · min−1 and 0.60 m · min−1, this was predominantly reflected in the core areas. The effective segregation length proportion of the bloom and rolled bar is approximately 40%. This phenomenon fully verifies the heredity characteristics of the elements in the rolling process.
{"title":"Improvement of carbon segregation in cast bloom and heredity in hot-rolled bar","authors":"Mengyun Zhang, Y. Bao, Li-hua Zhao, Xin Li","doi":"10.1051/metal/2021072","DOIUrl":"https://doi.org/10.1051/metal/2021072","url":null,"abstract":"In this study, the effect of mechanical soft reduction on carbon segregation in the continuous casting of 300 × 400 mm 42CrMo alloy structural steel blooms was comparatively investigated by adjusting the casting speed, which was systematically optimized through numerical simulation. When the casting speed is 0.60 m · min−1, during the soft reduction process, the central solidification structure of the bloom becomes dense, and carbon segregation is improved. Moreover, the distribution of carbon in the samples before and after rolling was analyzed. Combined with the soft reduction process, the uniformity of carbon across the cross section of the bloom /bar distinctly improved for casting speeds of 0.50 m · min−1, 0.55 m · min−1 and 0.60 m · min−1, this was predominantly reflected in the core areas. The effective segregation length proportion of the bloom and rolled bar is approximately 40%. This phenomenon fully verifies the heredity characteristics of the elements in the rolling process.","PeriodicalId":18527,"journal":{"name":"Metallurgical Research & Technology","volume":"18 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79958083","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}
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