P550无磁钻铤螺纹孔不同成形工艺的组织与疲劳寿命研究  

Microstructure and Fatigue Life of P550 Non-magnetic Drill Collar Threaded Holes Using Different Forming Processes

作　　者：秦才会[1] 王仡仡 徐志刚 杨中娜 曹云风 潘佳鑫 崔丽颖 QIN Caihui;WANG Yiyi;XU Zhigang;YANG Zhongna;CAO Yunfeng;PAN Jiaxin;CUI Liying(Well Tech Research Institute,China Offshore Services Limited,Hebei Langfang 065201,China;CNOOC(Tianjin)Pipeline Engineering Technology Co.,Ltd.,Tianjin 330452,China)

机构地区：[1]中海油田服务股份有限公司油田技术研究院,河北廊坊065201 [2]中海油(天津)管道工程技术有限公司,天津330452

出　　处：《精密成形工程》2025年第4期160-169,共10页Journal of Netshape Forming Engineering

基　　金：国家重点研发计划(2024YFC3014004)。

摘　　要：目的针对随钻仪器无磁钻铤切削成形的螺纹孔疲劳裂纹,通过断口分析研究失效机理,探究切削和冷挤压成形螺纹孔的疲劳寿命。方法通过对切削成形和冷挤压成形螺纹孔的钻铤模拟件进行弯曲疲劳试验,对比研究了2种成形工艺螺纹孔的组织和性能,用超景深显微镜研究断口形态,用场发射扫描电镜定点测量疲劳条带间距,建立了裂纹扩展速率da/dN与裂纹长度a的数学公式,计算了疲劳裂纹的扩展速率并估算了疲劳裂纹的萌生寿命。结果钻铤模拟件与失效件的裂纹位置一致,断口性质相同,均为高周弯曲疲劳断口;钻铤模拟件切削螺纹孔的试验寿命为545.8 h,与钻铤螺纹孔的实际寿命526 h十分接近;由Paris公式计算出螺纹孔的裂纹萌生寿命占总疲劳寿命的84%;加上盖板槽并拧紧螺钉可使螺纹孔的使用寿命延长210%。结论冷挤压成形螺纹孔使表层330μm内生成纤维状细晶组织、显微硬度增加,加工表面完整性改善,相较于切削螺纹孔,冷挤压螺纹孔的无磁钻铤疲劳寿命提升了32%。The work aims to analyze the failure mechanism of threaded holes by analyzing the fracture of the non-magnetic drill collar while drilling instrument,to investigate ways for extending the fatigue life of cutting and extruding threaded holes.In this paper,bending fatigue tests were conducted on simulated drill collars with cutting and cold extrusion threaded holes.A comparative study on the microstructure and properties of threaded holes in two forming processes was conducted.Appearance of fracture,striation spacing of fatigue were characterized by stereomicroscope and FSEM.The mathematical formula of crack propagation rate da/dN and crack length was established to calculate the fatigue crack propagation rate and estimate the initiation life of the fatigue crack.The results showed that the crack locations of the copy workpiece and the failure workpiece were the same,and the fracture properties were the same,both of them were high cycle bending fatigue fractures.The test life of cutting thread holes of the drill collar mold was 545.8 h,which was very close to the actual life of the drill collar thread hole of 526 h.According to the Paris formula,the crack initiation time of the thread hole accounted for 84%of the total life.The service life of threaded holes could be increased by 210%by adding cover slots and tighten screws.Extrusion of the thread hole creates a 330μm fibrous texture on the surface of the thread,increasing the micro-hardness,improving the surface integrity of thread processing and the fatigue life of the drill collar.The fatigue life of extruded thread hole is increased by 32%compared with that of the cut thread hole.

关 键 词：无磁钻铤 随钻仪器 螺纹孔疲劳裂纹 切削与冷挤压 疲劳寿命反推 裂纹扩展速率 

分 类 号：TH162[机械工程—机械制造及自动化] TG62[金属学及工艺—金属切削加工及机床]