含碳量对CrMo系高强钢应力腐蚀断裂行为的影响

EFFECT OF CARBON CONTENT IN HIGH STRENGTH CrMo STEEIS ON THEIR STRESS CORROSION CRACKING BEHAVIOR

一、引言实验结果表明,高强钢含碳量增高时,应力腐蚀断裂和氢脆抗力将显著下降。碳的这种不利作用常被归因于使钢的屈服强度升高而改变了裂纹尖端的应力水平。然而Sandaz在AISI 4340型钢上的工作表明,即使在屈服强度相同的条件下,含碳量的增高仍使K_(ISCC)值显著降低。因此有必要进一步研究碳的作用机制。

The effect of carbon content in high strength CrMo steels on their stress corrosion cracking behavior in 3.5 % NaCl aqueous solution has been studied. Results show that at the same tempering temperature,an increasing carbon content results in the rise of intergranular fracture tendency and the reduction of K_(ISCC). The main cause for them is the presence of more carbide particles at the prior austenitic grain boundaries. Both the increasing yield strength and more twin martensite contribute to the reduction of the resistance of the steels to stress corrosion cracking.