Development And Production Of Hot Rolled Steel Strip For TG Oil Casing

In recent years,the demand for oil and natural gas resources has increased,and the demand for oil casing has increased year by year.However,due to the increasingly complex mining environment,the use of high-performance seamless oil casing has increased year by year,resulting in high seamless steel pipe manufacturing costs.As a result,the profit margin of oil and gas exploration is gradually compressed.The oil casing produced by the hot-rolled steel strip in the petroleum industry through the straight seam resistance welding process is a low-cost and high-value-added product,which greatly reduces the manufacturing cost of seamless steel pipes.In order to meet the market ' s demand for low-cost casing,this article takes the factory as the background and product industrialization as the goal,and takes the hot-rolled steel strip for petroleum casing as the research object.The chemical composition,heating process,and rolling Systematic research has been carried out on several aspects of manufacturing process,pipe manufacturing process and steel strip surface quality.Through the design of the composition and hot rolling process of the hot-rolled steel strip for TG petroleum casing,the chemical composition adopts the design of medium C(carbon),Mn(manganese),and Nb(niobium)composition system,and conducted pilot test studies.The mechanical properties meet the technical requirements,and the microstructure is mainly a large amount of ferrite and pearlite,which lays the foundation for the development of small batch industrial trial production.Through small batch trial production,statistics and analysis of on-site rolling parameters are carried out,and the rolling process of hot-rolled steel strip for TG petroleum casing is summarized and optimized,so that the mechanical properties of the product meet the technical requirements.The yield strength is greater than 530 MPa,the tensile strength is greater than 650 MPa,the full-scale transverse impact energy is greater than 75 J,the hardness is in the range of 180-230 HV,the total inclusions are less than 2.0,the band structure is less than 2.0,and the grain size is greater than 12.The relationship between various process parameters and mechanical properties in the process of pipe making was studied,and the pipe making process was solidified by summing up and optimizing the process parameters of welding,intermediate frequency heating and controlled cooling.After the pipe is made,the yield strength of the pipe body is greater than 450 MPa,the tensile strength of the pipe body and the weld seam is greater than 590 MPa,the impact energy is greater than 40 J,the pipe body flattening test has no cracks,and all mechanical properties meet the technical requirements,but the surface quality of the pipe is insufficient.In order to further improve the surface quality of the casing,after studying the oxide composition and production conditions,by reducing the element Si content,optimizing the heating temperature and heating time,and increasing the rough rolling descaling pass,the red oxide on the surface of the steel strip has been well controlled..This research lays the foundation for the mass production of hot-rolled steel strips for TG oil casing in a factory's 2250 mm production line.