Oil casing can be made from seamless steel pipe, high frequency resistance welding (HFW), high frequency welding hot rolled electrical (seam). Welded oil shells have been widely used in oil field production. HFW oil casing is made of hot-rolled coil/plate and undergoes a series of processes such as extrusion molding, HFW welding, welding annealing and full-pipe heat treatment. It has the advantages of good toughness, high dimensional accuracy and extrusion strength, but the performance of the welding microstructure and the performance of the base material are completely different from the content of high groove sensitivity.
Sewing oil casing
Compared with other welding methods, HFW welds do not have metal fillers and their welding performance depends on the welding process and heat treatment. SEC casing tube combination HFW welding, hot draw reduction and full heat treatment process, i.e. welding low carbon low alloy TMCP hot rolled coil/plate, heating heating tube (20℃ to 50.℃) to AC3 austenite phase Variable temperature (above 900°C - 1100.°C), the rolling unit reduces the diameter and brings thermo-mechanical treatment, with good toughness and dimensional accuracy.
Sealing can be regarded as a mature and widely used oil casing manufacturing process. Compared with seamless pipes of the same steel grade, sewn oil casing has good toughness (impact toughness increased by about 30%), high geometric accuracy and small wall thickness tolerance, which can reduce steel pipe consumption by about 3% The wells are at the same depth, achieving continuous and efficient production of the same pipelines of different specifications. Experiments have shown that the strength of sewn N80Q pipes has been greatly reduced after heat treatment, and the strength and toughness have been greatly improved.
It can be confirmed that the performance of the seam shell is better than that of the ordinary shell. On the basis of meeting API standards, the SEW shell has high geometric dimensional accuracy and higher extrusion strength, which can meet the requirements of conventional oil wells and ordinary injection holes. Currently, anti-extrusion N80*9.17mm seam pipe and P110TT*10.54mm seam pipe have been widely used in oceans with an average depth of 2,000 meters
