不同显微组织套管钻井用钢的拉伸性能与疲劳裂纹扩展性能

Tensile Property and Fatigue Crack Growth Property of Casing-Drilling Steels with Different Microstructures

通过万能试验机、疲劳试验机、扫描电镜等设备研究了三种不同显微组织套管钻井用钢的拉伸性能和疲劳裂纹扩展性能,并建立了不同参数之间的定量关系。结果表明:回火马氏体钢的抗拉强度和屈服强度显著高于珠光体-铁素体钢的和铁素体-贝氏体-回火马氏体钢的;珠光体-铁素体钢的Paris常数m最大、C最小,回火马氏体钢的Paris常数m最小、C最大;对于具有相同或相近成分的钢来说,Paris常数m随着屈服强度的增大而显著减小,Paris常数C随着伸长率的增加而显著减小;不同钢的Paris常数C随着Paris常数m的减小而增大;当通过热处理使得钢的拉伸性能提高到一定程度时,必须通过改变其成分来获得良好的综合性能。

The fatigue crack growth properties and tensile properties of three casing-drilling steels with different microstructures were conducted by scanning electron microscope,fatigue test machine,and universal test machine.The quantitative relationship of different parameters was built.The results show that the tempered martensite steel possessed significantly higher tensile strength and yield strength than ferrite-bainite-tempered martensite steel and pearlite-ferrite steel.Pearlite-ferrite steel had the maximum Paris constant m and minimum Paris constant C.Tempered martensite steel had minimum Paris constant m and the maximum Paris constant C.For steels with the same or similar chemical composition,Paris constant m decreased evidently with the increase of yield strength and Paris constant Cdecreased significantly with the increase of elongation.For different steels,Paris constant Cincreased with the decrease of paris constant m.The materials composition should be modified to obtain excellent combination properties when the tensile properties were improved to the critical value by means of heat treatment.