中高碳钢晶粒度测定方法研究
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摘要
国标中氧化法与直接淬硬法是测定碳含量在0. 25%～1. 00%钢中晶粒度的主要方法,然而运用这两种方法得出的晶粒尺寸往往出现偏小的情况。本文通过对55SiCr弹簧钢分别运用直接腐蚀法、EBSD法、氧化法与直接淬硬法测定晶粒度,经过比较与分析得出:氧化法与直接淬硬法测得的晶粒尺寸相比较直接腐蚀法与EBSD法要小,其原因在于热处理后的试样中含有残留奥氏体小晶粒,在用软件评级时,误将一个大的晶粒因为残留奥氏体晶界的拐入而分割成两个小晶粒来统计,从而造成晶粒尺寸的偏小。人工去掉小晶粒或假设未考虑残留奥氏体时截点数为n,考虑残留奥氏体的影响,其截点数约为n+Dn,测量线段长度为L,校正前后的晶粒度分别为Z_1和Z_2,则有Z_1=L/n,Z_2=L/(n+Dn),进一步可以得出Z_2=Z_1/(1+D)。经这两种方法校正后得到的结果与直接腐蚀法和EBSD法获得的结果较为接近。
The oxidation method and direct quenching method in the national standard are the main methods for determining the grain size of steel with a carbon content of 0. 25%-1. 00%. However,the grain size results determined by these two methods are smaller than they actually are. In this paper,the grain size of 55 SiCr spring steel was measured by direct corrosion method,EBSD method,oxidation method and direct hardening method,respectively. After comparison and analysis,it is found that the grain sizes measured by oxidation method and direct hardening method are smaller. The reason is that the specimens after heat treatment contain small retained austenite grains. When calculating with a software,a large grain will be miss-divided into two small grains due to the turning-in of retained austenite grain boundaries,resulting in a small grain size. After artificially removing small grains,or without considering the retained austenite,the number of intercept points can be assumed n. Considering the influence of retained austenite,the number of intercept points is about n + Dn,the length of the measuring line is L,and the grain sizes before and after the correction are Z_1 and Z_2 respectively. Then there is Z_1= L/n,Z_2=L/( n + Dn). Further Z_2= Z_1/( 1 + D) can be drawn. The results after correction are similar to those of direct corrosion method and EBSD.
The oxidation method and direct quenching method in the national standard are the main methods for determining the grain size of steel with a carbon content of 0. 25%-1. 00%. However,the grain size results determined by these two methods are smaller than they actually are. In this paper,the grain size of 55 SiCr spring steel was measured by direct corrosion method,EBSD method,oxidation method and direct hardening method,respectively. After comparison and analysis,it is found that the grain sizes measured by oxidation method and direct hardening method are smaller. The reason is that the specimens after heat treatment contain small retained austenite grains. When calculating with a software,a large grain will be miss-divided into two small grains due to the turning-in of retained austenite grain boundaries,resulting in a small grain size. After artificially removing small grains,or without considering the retained austenite,the number of intercept points can be assumed n. Considering the influence of retained austenite,the number of intercept points is about n + Dn,the length of the measuring line is L,and the grain sizes before and after the correction are Z_1 and Z_2 respectively. Then there is Z_1= L/n,Z_2=L/( n + Dn). Further Z_2= Z_1/( 1 + D) can be drawn. The results after correction are similar to those of direct corrosion method and EBSD.
引文
[1]崔忠圻,覃耀春.金属学与热处理[M].北京:机械工业出版社,2007.
[2]罗检,张勇,钟庆东,等.晶粒度对一些常用金属耐腐蚀性能的影响[J].腐蚀与防护,2012,33(4):349-352.Luo Jian,Zhang Yong,Zhong Qingdong,et al.Influence of grain size on corrosion resistant of commonly used metals[J].Corrosion and Protection,2012,33(4):349-352.
[3]乔亚楠,刘新宽,刘平,等.B82Mn钢盘条奥氏体晶粒度检测方法[J].金属热处理,2017,42(3):151-154.Qiao Yanan,Liu Xinkuan,Liu Ping,et al.Testing methods for austenitic grain size of B82Mn steel wire rods[J].Heat Treatment of Metals,2017,42(3):151-154.
[4]于桂玲.60Si2CrVAT弹簧钢奥氏体晶粒度检测方法[J].物理测试,2013,31(1):25-28.Yu Guiling.Testing method for austenite grain size of 60Si2CrVATspring steel[J].Physics Examination and Testing,2013,31(1):25-28.
[5]李平,王雷,麻晗,等.82B盘条奥氏体晶粒度检测方法比较[J].热加工工艺,2014(8):101-102.Li Ping,Wang Lei,Ma Han,et al.Comparison of testing methods of austenitic grain size of 82B wire rods[J].Hot Working Technology,2014(8):101-102.
[6]俞秋景,杨金艳.高碳钢盘条晶粒度检测方法比较[J].金属热处理,2012,37(6):118-120.Yu Qiujing,Yang Jinyan.Comparison of grain size detection method for high carbon steel wire rods[J].Heat Treatment of Metals,2012,37(6):118-120.
[7]顾佳卿,赵伟峰,张志霞.EBSD技术在不锈钢研究中的应用[J].宝钢技术,2014(3):63-68.Gu Jiaqing,Zhao Weifeng,Zhang Zhixia.Application of EBSDanalysis technology in stainless steel research[J].Baosteel Technology,2014(3):63-68.
[8]肖玄,陈敏.SWRH72A帘线钢盘条晶粒度测试方法[J].金属热处理,2016,41(4):201-204.Xiao Xuan,Chen Min.Grain size measuring methods for SWRH72Atire cord steel[J].Heat Treatment of Metals,2016,41(4):201-204.
[9]刘天佑.氧化法检验钢的奥氏体晶粒度的研究[J].理化检验-物理分册,2000,36(11):501-504.Liu Tianyou.Study on austenite grain size examination by oxidization method[J].Physical Testing and Chemical Analysis Part A(Physical Testing),2000,36(11):501-504.
[10]张卫.钢的奥氏体晶粒度检验方法[J].热加工工艺,2010,39(22):66-68.Zhang Wei.Inspection methods of austenitic grain size in stainless steel[J].Hot Working Technology,2010,39(22):66-68.
[2]罗检,张勇,钟庆东,等.晶粒度对一些常用金属耐腐蚀性能的影响[J].腐蚀与防护,2012,33(4):349-352.Luo Jian,Zhang Yong,Zhong Qingdong,et al.Influence of grain size on corrosion resistant of commonly used metals[J].Corrosion and Protection,2012,33(4):349-352.
[3]乔亚楠,刘新宽,刘平,等.B82Mn钢盘条奥氏体晶粒度检测方法[J].金属热处理,2017,42(3):151-154.Qiao Yanan,Liu Xinkuan,Liu Ping,et al.Testing methods for austenitic grain size of B82Mn steel wire rods[J].Heat Treatment of Metals,2017,42(3):151-154.
[4]于桂玲.60Si2CrVAT弹簧钢奥氏体晶粒度检测方法[J].物理测试,2013,31(1):25-28.Yu Guiling.Testing method for austenite grain size of 60Si2CrVATspring steel[J].Physics Examination and Testing,2013,31(1):25-28.
[5]李平,王雷,麻晗,等.82B盘条奥氏体晶粒度检测方法比较[J].热加工工艺,2014(8):101-102.Li Ping,Wang Lei,Ma Han,et al.Comparison of testing methods of austenitic grain size of 82B wire rods[J].Hot Working Technology,2014(8):101-102.
[6]俞秋景,杨金艳.高碳钢盘条晶粒度检测方法比较[J].金属热处理,2012,37(6):118-120.Yu Qiujing,Yang Jinyan.Comparison of grain size detection method for high carbon steel wire rods[J].Heat Treatment of Metals,2012,37(6):118-120.
[7]顾佳卿,赵伟峰,张志霞.EBSD技术在不锈钢研究中的应用[J].宝钢技术,2014(3):63-68.Gu Jiaqing,Zhao Weifeng,Zhang Zhixia.Application of EBSDanalysis technology in stainless steel research[J].Baosteel Technology,2014(3):63-68.
[8]肖玄,陈敏.SWRH72A帘线钢盘条晶粒度测试方法[J].金属热处理,2016,41(4):201-204.Xiao Xuan,Chen Min.Grain size measuring methods for SWRH72Atire cord steel[J].Heat Treatment of Metals,2016,41(4):201-204.
[9]刘天佑.氧化法检验钢的奥氏体晶粒度的研究[J].理化检验-物理分册,2000,36(11):501-504.Liu Tianyou.Study on austenite grain size examination by oxidization method[J].Physical Testing and Chemical Analysis Part A(Physical Testing),2000,36(11):501-504.
[10]张卫.钢的奥氏体晶粒度检验方法[J].热加工工艺,2010,39(22):66-68.Zhang Wei.Inspection methods of austenitic grain size in stainless steel[J].Hot Working Technology,2010,39(22):66-68.