淬火温度对GE1014超高强度钢组织及性能的影响

采用力学性能测试、透射电镜(TEM)、X射线衍射(XRD)仪和电子背散射衍射(EBSD)等分析方法,研究了淬火温度对GE1014超高强度钢组织及性能的影响。结果表明,试验钢的抗拉强度随淬火温度的升高先逐渐升高,随后降低,并且在925 ℃达到峰值2112 MPa,规定塑性延伸强度则呈现随淬火温度的升高小幅降低的趋势,试验钢的断面收缩率和U型冲击性能均随淬火温度的升高缓慢升高,在950 ℃附近出现降低趋势;试验钢的原始奥氏体晶粒和马氏体块的尺寸都随着淬火温度的升高而长大,当淬火温度超过925 ℃时,原始奥氏体晶粒尺寸快速粗化,而马氏体块尺寸则全程长大缓慢;850~925 ℃范围内,基体中的残留奥氏体含量随着淬火温度的升高而显著降低;淬火温度低于900 ℃时,试验钢中存在球状富Mo型M₆C碳化物,淬火温度升高至900 ℃未观察到未溶相。

Effect of quenching temperature on microstructure and mechanical properties of GE1014 ultra-high strength steel

Effect of quenching temperature on mechanical properties and microstructure of the GE1014 ultra-high strength steel was studied by means of mechanical property test, transmission electron microscope(TEM), X-ray diffraction(XRD), electron backscatter diffraction(EBSD) and other analysis methods. The results show that with the increase of quenching temperature, the tensile strength of the tested steel increases first and then decreases and the peak value is 2112 MPa when quenched at 925 ℃, the proof strength, plastic extension decreases slightly with the increase of quenching temperature. The reduction of area and U-notched impact property of the tested steel increase slowly with the increase of quenching temperature, and decrease at near 950 ℃. Both the prior austenite grain size and martensite block size of the tested steel increase with the increase of quenching temperature. When the quenching temperature exceeds 925 ℃, the prior austenite grain coarsens rapidly, while the martensite block grows slowly throughout the whole process. In the range of 850-925 ℃, the volume fraction of retained austenite in the matrix decreases significantly with the increase of quenching temperature. When the quenching temperature is lower than 900 ℃, there are spherical Mo-rich M;C carbides in the tested steel, while when higher than 900 ℃, no insoluble phase is observed.