Low temperature tempering is also known as "stress relief tempering". The structure after tempering is tempered martensite.

On the surface of seamless steel pipes, scraps and extremely fine microscopic metal particles appear on the surface, which are called burrs. The more glitches, the lower its quality standard. The types of burrs mainly include flash burrs, sharp corner burrs, splashes, etc.

Straight seam steel pipe is a welded steel pipe with the weld seam parallel to the longitudinal direction of the steel pipe.

SSAW steel pipe is a spiral seam welded steel pipe made of strip steel coil as raw material. It is often extruded at high temperature and welded by spiral submerged arc welding.

Oil pipelines, as important equipment for oilfield production and oil and gas transportation, will suffer severe corrosion after long-term use. If the pipeline anti-corrosion work is not in place, it will not only reduce the service life of the oil pipeline, but also have a negative impact on the quality of oil products, and will cause serious environmental pollution.

Carbon (C): The carbon content in the steel increases, the yield point and tensile strength increase, but the plasticity and impact decrease.