The Effect Of Extrusion Texture On The Mechanical Properties And Corrosion Resistance Of Aluminum Alloy Drill Pipes

The aluminum alloy drill pipe is produced by extrusion.Due to the extrusion process,it will produce strong anisotropy in the axial and radial direction of the extruded pipe,and it will also have a corresponding texture.The texture is widely present in aluminum alloy products and affects a range of properties of the material,including strength,ductility,formability,and corrosion.At present,a lot of researches have been done on the evolution of texture during the manufacture and processing of aluminum alloys.However,the research on the effect of texture on the properties of drill pipe materials is not thorough enough,and the conversion of research results to industrial applications is less.At the same time,when the aluminum alloy drill pipe is actually used for drilling,the aluminum alloy drill pipe will not only be subjected to a combination of forces such as stretching,compression and impact,but also be subjected to erosion by drilling fluids and other corrosive media.Therefore,the aluminum alloy drill pipe has a higher requirement for its own mechanical and electrochemical properties under the actual operating conditions.Therefore,it is of practical significance to study the effect of texture on mechanical properties and electrochemical properties.In this paper,XRF was used to analyze the composition of the drill pipe material.The XRD was used to analyze the macro-texture existing in the cross-section and longitudinal profile of the pipe section of the aluminum alloy pipe.The EBSD was used to analyze the micro-texture and grain orientation existing in the aluminum alloy pipe in the cross-section and longitudinal section.Sampling along the extrusion direction of the drill pipe and perpendicular to the extrusion direction is used to test the mechanical properties,ie,the universal tensile testing machine is used to test the tensile properties at room temperature,and the INSTRON 5982 electronic universal material testing machine is used to perform the room temperature compression test on the materials.The BDW-300Y impact tester was used for room temperature impact test,and the effect of texture on the mechanical properties of aluminum alloy pipe body was analyzed.Corrosion immersion method was used to study the pitting behavior and intergranular corrosion behavior of the cross-section and longitudinal section of the pipe section of aluminum alloy drill pipe in 3,5%NaCl solution.And the effect of texture on electrochemical performance of the pipe section of the aluminum alloy drill pipe was analyzed.Research shows:(1)The extrusion texture results in a strong anisotropy in the longitudinal(in the extrusion direction)and transverse(perpendicular to the extrusion direction)of the aluminum alloy drill pipe body section,in the 2A12T4 aluminum alloy drill pipe,There are textures<001>and<111>in the longitudinal direction,texture<223>in the transverse direction,and relatively weak texture<101>,the D16T aluminum alloy pipe body segment has textures in the longitudinal direction<112>and<111>,<101>and<001>textures exist laterally.(2)When it contains more<001>texture in the body segment of 2A12T4 aluminum alloy drill pipe,the plasticity performs best,<111>and<101>followed,<223>relatively the worst.For body segment of D16T aluminum alloy drill pipe,the plasticity is best when the content of<001>texture is higher,<111>and<101>textures are next,and<112>is relatively poor.In addition,for the tube sections of two kinds of aluminum alloy drill pipe materials,the existence of the extrusion texture makes the mechanical properties in the transverse and longitudinal directions have certain anisotropy,ie,the longitudinal integrated mechanical properties in the same material are better than comprehensive mechanical properties in the transverse direction.The comparison of the two materials shows that the composite mechanical properties of the D16T aluminum alloy drill pipe material are superior to those of the 2A12T4 aluminum alloy drill pipe material.(3)During electrolytic polishing,in the longitudinal section and cross-section of the pipe sections of the two aluminum alloy drill pipe materials are more likely to be corroded with crystal grains with larger differences in the orientation of the peripheral grains.(4)The cube-textured{001}<100>,rotated cube-textured {001}<110>,and {112}<110>and {111}<112>textures are present in the cross section of the pipe section of the 2A12T4 aluminum alloy drill pipe.When immersed in 3.5%NaCl solution,no significant difference was found in the ability to resist pitting corrosion.The {110}<112>brass texture of 2A12T4 aluminum alloy pipe section is better than that of Goss texture {011}<100>and cubic Structured {001}<100>to resist pitting corrosion.The(112}<110>texture of the D16T aluminum alloy drill pipe has a better resistance to pitting than the {111}<112>texture.The {001}<100>and {110}<112>textures performs better to resist pitting corrosion than {112}<111>texture in the D16T aluminum alloy drill pipe in longitudinal section.In addition,the {001}<100>and {110}<112>textures present in the vertical section of D16T make the vertical section has better ablity to resist pitting than the cross-section.(5)The proportion of high-angle grain boundaries in the cross-section of the pipe sections of two aluminum alloy drill pipe materials is higher than that of high-angle grain boundaries in the longitudinal profile,making the longitudinal section more resistant to intergranular corrosion than the cross-section in the same kind of material.