D级空心抽油杆疲劳性能试验研究

为考查Ｄ级空心抽油杆不同摩擦焊接工艺性能的可靠性， 采用电测试验应力法测试抽油杆焊接接头的应力集中系数β。在静拉伸条件下进行应变测试， 测得抽油杆焊接接头平均应力集中系数为１－０９１５ ， 各应力集中系数分散性较小， 说明摩擦焊接工艺稳定可靠。在ＭＴＳ—８１０材料试验机上做了抽油杆短杆接头的疲劳试验， 采用数理统计方法统计分析Ｄ 级空心抽油杆疲劳性能， 获得Ｄ级杆的Ｐ－ Ｓ－ Ｎ 曲线和疲劳极限图， 求得存活率Ｐ＝ ９９－９ ％ 及对应寿命Ｎ＝ １０７时抽油杆的最大应力水平为２４４－３７ＭＰａ。统计结果表明， 按有关工艺制造的Ｄ级空心抽油杆疲劳强度满足使用要求。

Fatigue test of grade D sucker rod

In order to examine the reliability of different friction welding technologies for grade D hollow sucker rod, the stress concentration coefficients of sucker rod welding joints are tested with the electrometrical test method. Strain test made under static tension shows that, the stress concentration coefficients of the rod welding joints vary in a fairly narrow range, and the mean value is 1 0915, this means the friction welding technology is stable and reliable. Fatigue test of sucker rod substitutes is made on Model MTS—810 material test machine. The fatigue property of grade D hollow rod is analyzed by using the mathematical statistics method, and the P-S-N curve and fatigue limit diagram are obtained. The calculation shows that the maximum stress of sucker rod is 244 37MPa when the livability is 99 9% and the corresponding life is 10 7. The statistics result proves the fatigue strength of grade D hollow rod manufactured with relevant technologies satisfying operation requirements.