钢的韧脆转移显微组织诊断技术和方法的研究

通过对10、20、35、45、55、70和T8A钢等一系列碳钢显微组织参量与其韧脆转移温度之间的关系研究，找到了共析片状珠光体钢和铁素体＋片状珠光体亚共析钢的韧脆转移过程的显微组织特征参量可以统一由复合组织参量D来表征。因此可以认为复合组织尺寸是解理断裂的“有效晶粒”大小。这一研究成果为估算碳钢的韧脆转移T C及诊断冷脆断裂的可能性提供了定量的有效的依据。

THE TECHNOLOGY AND METHOD OF MICROSTRUCTURE DIAGNOSTIC OF DUCTILE-BRITTLE TRANSITION IN STEELS

In this paper, following result are found, microstructural charaterialic parameter of ductile-brittle transition in eutectoid steel of lamellar pearlite and subeutecield steels of ferrite+lamellar pearlite can be integratively expressed by compound structural charteristic parameter, D(D=dp+pp, D≈dj), by researching relationship between ductile-brittle transition temperature and microstructural characteristic parameter in steels of 10, 20, 35, 45, 55, 70 and T8A etc., and following equations are obtained: Tc=483.81-22.7dj-1/2 corr. = 0.9924 Tc=486.15-22.82D-1/2 corr. =0.9966 Therefore, compound structure size can be regarded as size of “effective grain” of cleavage fracture. The research results provide a quantitative and effective method for evaluating ductile-brittle transition temperature, Tc and diagnosing cold brittle fracture.