1Cr18Ni9不锈弹簧钢丝冷拔组织分析

Cold drawing microstructure analysis of 1Cr18Ni9 stainless steel wire for spring

1Cr18Ni9不锈弹簧钢丝拉拔过程中的强化形式主要是形变强化,强化效果由3种因素造成:奥氏体加工硬化、形变诱发马氏体强化和马氏体加工硬化,其中形变诱发马氏体强化是主要因素。经过总压缩率为43.7%拉拔后,在白亮的奥氏体基体上有黑色的呈板条分布的马氏体;经过总压缩率为75%拉拔后,奥氏体进一步转化为马氏体,板条状的马氏体大部分发生扭曲变形;经过超过90%总压缩率拉拔后,横截面上晶界遭到破坏,晶粒更加细小,形变马氏体数量明显增加,纵截面上细小的马氏体纤维中间出现白亮的奥氏体细小纤维组织。X射线衍射分析表明:经过不同总压缩率拉拔的钢丝衍射图谱中出现了明显的马氏体衍射峰ε和α′,随着总压缩率的增大,奥氏体衍射峰强度逐渐降低,马氏体衍射峰强度则逐渐增加。当总压缩率为96%时,马氏体组织的体积分数达到97.63%。

The strengthening way is mainly deformation strengthening while 1Cr18Ni9 stainless steel wire for spring is in the process of wire drawing, the factors are tile following three ways as austenite work hardening, deformation induced martensite strengthening and martensite work hardening, which deformation induced martensite strengthening is the main factor. There is black lath distribution martensite on white bright austenite matrix after wire drawing of total compressibility 43.7%. The austenite transforms into martensite further and most lath martensite occurs distortion after wire drawing of total compressibility 75%. The grain boundary is destroyed, grain size is smaller, volume fraction of deformation martensite increased obviously on cross section, bright austenite fine fiber structure occurs in fine martensite fiber on longitudinal section after wire drawing of total compressibility 90%. X-ray diffraction analysis shows that obvious martensite diffraction peak and a＇ occurs in steel wire diffraction pattern drawn after different total compressibility, austenite diffraction peak strength decreases slowly and martensite diffraction peak strength increases slowly with total compressibility increasing. When total compressibility is 96%, volume fraction of martensite structure reaches 97.63%.