Large-diameter straight seam steel pipe is a welded steel pipe whose weld seam is parallel to the longitudinal direction of the steel pipe. It is usually divided into metric electric welded steel pipe, electric welded thin-walled pipe, transformer cooling oil pipe and so on.

Steel pipes are divided into seamless pipes and welded pipes according to whether there are welds or not. A seamless pipe is a long strip of steel with a hollow section and no seams around it. Welded pipe is a steel pipe made of steel plate or strip steel after being crimped and welded.

Seamless steel pipes have hollow cross-sections and are widely used as pipes for transporting fluids, such as pipes for transporting oil, natural gas, gas, water and certain solid materials.

Seamless steel pipe is a round, square, or rectangular steel with a hollow section and no seams around it. Seamless steel pipes are made of steel ingots or solid tube blanks that are perforated into capillary tubes, and then made by hot rolling, cold rolling or cold drawing.

Seamless steel pipe is a pipeline widely used to transport fluids, such as natural gas, oil, and water pipelines.Seamless steel pipes can be divided into hot-rolled seamless steel pipes and cold-rolled seamless steel pipes. Hot-rolled seamless steel pipes are also called general steel pipes, which can be divided into low and medium pressure boiler steel pipes.

Oil casing is a steel pipe used to support the walls of oil and gas wells to ensure the normal operation of the entire oil well after the drilling process and completion. Each well uses several layers of casing according to different drilling depths and geological conditions.