高强度钢内螺纹冷挤压强化研究

Study on Internal Threads in High Strength Steels by Cold Form Tapping

研究了高强度钢内螺纹挤压强化对疲劳性能的影响。利用高精度云纹干涉法和扫描电镜 ,分别对螺纹牙根残余应力和疲劳试件断口进行了测试和观察 ,。疲劳对比试验结果表明 ,在应力为 50 0和 60 0 MPa的条件下 ,经挤压强化的 30 0 M高强度钢内螺纹的寿命是切削螺纹的 4～ 30倍。

WT5BZ]The influence of strengthening of internal threads by cold form tapping on the fatigue property of high strength steel is investigated In order to strengthening mechanism of formed threads residual stresses near to the root of the threads is measured by Moir Interferometry, and the fracture of sample is surveyed by means of SEM The results of fatigue tests shows that fatigue lives of the threads of 300M steel strengthened by forming tap are from four to thirty times longer than those of cut threads at the stress of 500 and 600MPa