Study On Strength And Toughness Of No Joint Wire-line Coring Drilling Pipes

Drilling work provide a large number of the information below the earth surface forthe human, beings. Scientific drilling, geological drilling and exploration drilling areinseparable from the drill pipe. Drill pipe material must have the excellent physical andchemical properties according to the working conditions. These excellent properties isdetermined by materials composition and some processing.Through a large number of experimental studies, material property analysis, andcomparison of several different materials and cost-effective,410S stainless steel isultimately selected for drill pipe material.We study and analyzes the performance of stainless steel410S and processperformance to explore its feasibility as a drill pipe materials. By referring to related test,test program is identified. Mechanical properties are measured by the tensile, impact, andhardness test. Its performance is evaluated by means of observing the microstructure,fracture morphology and spectrum analysis. Through a series of test performance datacomparison, heat treating process of the410S stainless steel as the drill pipe material isdetermined. It will provide a theoretical basis for drill pipe manufacturers.The so-called non-joint drill pipe is one between which connector is not used, For along time, the sample strength is only referred to as strength of thread connection. Thepaper introduces a testing method of drill pipe thread connection strength. Including drillpipe of overall thread connection and tool joint connection, devices and test method ofdetecting threaded connection(it is referred to as the overall strength test) are widely usedin measuring drill pipe thread connection strength of various caliber in the field.The test results show that the risk section of joint fracture part coincides with stressdistribution based on the finite element very well. The problem of strengthening at thecritical section problem should be taken seriously. Through observations from fracturelocation，some methods of strengthening connection are proposed.