冷却速率对55SiCr弹簧钢组织和性能的影响
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摘要
不同的冷却速率对轧制后的55SiCr弹簧钢力学性能和金相组织有较大的影响。在相变前和相变过程中,对55SiCr弹簧钢线材采用不同的冷却速率处理,并取样进行力学性能和金相组织检测,结果表明:随吐丝后高温段冷却速率的提高,试样抗拉强度逐渐增加,断面收缩率先增加后降低,脱碳层深度逐渐降低。而冷却速率过快时,容易产生异常马氏体组织,引起脆性断裂。因此在55SiCr弹簧钢线材轧制后冷却过程中,应先选择适当的冷却速率,快速冷却至690℃左右,然后入保温罩保温,完成相变转变,可以得到性能优异、脱碳层深度小和索氏体化率高的弹簧钢线材。
Different cooling rate has great influence on the mechanical properties and microstructure of 55SiCr spring steel after rolling. During the phase change and transition,the 55SiCr spring steel wire is treated with different cooling rate,and take sample to test the mechanical properties and microstructure. Results show that with the increase of the cooling rate of the high temperature section,the tensile strength of the samples increased gradually,the reduction of area increased first and then decreased,the depth of the decarburization layer decreased gradually. When the cooling rate increases rapidly,it is easy to produce abnormal martensite,causing brittle fracture. Therefore,the cooling process of the 55SiCr spring steel wire after rolling,cooling fast to 690 ℃ or so at the appropriate cooling rate,and then into the heat holding cover,completing phase change,get excellent performance,small decarburization depth and high sorbite rate microstructure spring steel wire rod.
Different cooling rate has great influence on the mechanical properties and microstructure of 55SiCr spring steel after rolling. During the phase change and transition,the 55SiCr spring steel wire is treated with different cooling rate,and take sample to test the mechanical properties and microstructure. Results show that with the increase of the cooling rate of the high temperature section,the tensile strength of the samples increased gradually,the reduction of area increased first and then decreased,the depth of the decarburization layer decreased gradually. When the cooling rate increases rapidly,it is easy to produce abnormal martensite,causing brittle fracture. Therefore,the cooling process of the 55SiCr spring steel wire after rolling,cooling fast to 690 ℃ or so at the appropriate cooling rate,and then into the heat holding cover,completing phase change,get excellent performance,small decarburization depth and high sorbite rate microstructure spring steel wire rod.
引文
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[3]沈朴恒,王德炯,刘春利.深拉拔用55Si Cr A盘条断裂分析及解决方案[J].南钢科技与管理,2016(4):6-10.
[4]彭学艺,郑宏伟,王灿祥.弹簧钢55Si Cr A连续冷却相变规律[J].金属材料与冶金工程,2016(2):24-28.
[5]柳洋波,张玮,佟倩,等.炉气含氧量对弹簧钢55Si Cr脱碳的影响[J].金属热处理,2013(9):37-41.
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