温变形对700L高强钢碳化物析出行为及残余应力的影响

Effect of warm deformation on carbide precipitation behavior and residual stress of 700L high strength steel

采用裂纹柔度法(CCM)、X射线衍射分析、扫描电镜(SEM)、透射电镜(TEM)、显微维氏硬度计等研究了700L高强钢不同温度回火和温变形后内部组织和残余应力的变化。结果表明:相较于回火,温变形能促进700L高强钢中碳化物的析出;随温变形温度的升高,700L高强钢的整体残余应力持续下降,在100~300℃温变形时,残余应力快速下降,300℃温变形后残余应力下降至34.77%,在300~600℃温变形时,残余应力下降平缓,600℃温变形后,残余应力降低到20.83%,温变形对残余应力的调控作用显著。高温区间温变形还可以降低700L高强钢表面的拉应力水平,提高其疲劳性能。

Crack compliance method(CCM), X-ray diffraction analysis, scanning electron microscopy(SEM), transmission electron microscopy(TEM) and Vickers hardness tester were used to study the changes of internal microstructure and residual stress of 700 L high strength steel after tempering and warm deformation at different temperatures. The results show that compared to tempering, the warm deformation can promote the precipitation of carbides of the 700 L high strength steel. With the increase of the warm deformation temperature, the overall residual stress of the 700 L high strength steel decreases continuously. During warm deformation at 100-300 ℃, the residual stress decreases rapidly, and the residual stress of the 700 L high strength steel after warm deformation at 300 ℃ decreases to 34.77%. During warm deformation at 300-600 ℃, the residual stress decreases slowly, and the residual stress of the 700 L high strength steel after warm deformation at 600 ℃ decreases to 20.83%. The regulation of warm deformation on residual stress is significant. The high temperature deformation can also reduce the surface tensile stress level of the 700 L high strength steel, improve its fatigue performance.