超高强度抽油杆残余应力分布和衰减规律的研究

Study on the Distribution of Residual Stresses and the Regularity of Their Attenuation in the Sucker Rod of Super High Strength

以超高强度抽油杆为工程背景，对表面感应淬火和喷丸残余应力的产生过程及在外加拉伸载荷作用下，残余应力的衰减行为进行了数值及实验研究。结果表明：当感应淬火和喷丸强化前，杆体的屈服强度高于一定值后，其硬化层形成的残余应力基本一致；残余应力的衰减主要取决于心部屈服强度，心部屈服强度越高，使残余应力发生明显衰减的外加应力就越高；使残余应力明显衰减的外加应力介于整体杆拉伸强度的σ０．０１和σ０．２之间；经表面感应淬火和喷丸强化后，３５ＣｒＭｏ调质态杆的疲劳极限高于正火态疲劳极限。

Taking the sucker rod of saper high strength as engineering back ground, a study on the course of producing residual stress in surface induction hardening and shot,blasting as well as the attenuation behavior of residual stress under the action of external load of elongation is brought out numerically and experimentally. Results show that: as the yield strength of rod is higher than a certain value before induction hardening and shot-blast strengthening, the residual stresses in the hardening layer are idendical on the whole; the attenuation of residual stress depends mainly on the yield strength of the core,the higher the strength,the higher is the external stress needed for obvious attenuation; the external stress needed for obvious attenuation is between σ0.01 and σ0.20 of the elongation stress of total rod; after surface induction hardening and shot-blast strengthening, the fatigue limit of the hardened and tempered 35CrMo rod is higher than that of normalized one.