中低强钢和焊缝金属Charpy-V与COD转变温度的关系

Correlation between transition temperatures of Chaipy-V energy and COD of low and medium strength steels and weld metals

关键词:  冲击韧性  断裂韧性  延脆转变温度  应变速率敏感性  断裂过程  解理条件

Key words:  absorbed energy  fracture toughness  ductile-brittle transition temperature  strain rate sensitivity  fracture process  cleavage condition

摘要:

对普通C-Mn钢,Cr-Mo钢和三种焊缝金属进行了系列温度示波冲击试验,COD试验和屈服强度的测定,通过对试验结果的分析,发现中低强结构钢和焊缝金属的冲击韧性和COD的延脆转变温度之间存在着一定的相关关系,即试验材料的冲击韧性和断裂韧性的延脆转变温度迁移量与材料的应变速率敏感性呈线性关系。根据这一关系,推荐了工程上用冲击韧性推测COD的方法,并指出这一相关关系存在的内在原因是,不同试验材料的缺口冲击试样和裂纹静载试样在延性断裂过程及解理的力学条件这二个方面的相似性。

Abstract:

The instrumented Charpy impact tests, the COD tests and the measurement of yield strengths were carried out on C-Mn steels, Cr-Mo steel and three kinds of weld metals under various test temperatures. It was found through the analysis of the test results that there is a unified correlation between the ductile-brittle transition temperatures of impact toughness and the COD for the low and medium strength steels and their weld metals. This correlation is a linear relationship between the transition temperature shift of the bi-toughnesses and the strain rate sensitivities of the test materials. On the basis of this relationship, the method to estimate the COD according to the impact toughness is proposed for engineering application. The internal cause of this correlation is considered as that the ductile fracture processes and the mechanical condition of cleavage during the V-notched impact are similar to those during the precracked slow bending, no matter what type of specimen is used.