Boiler tube is a type of seamless tube. The manufacturing method is the same as that of seamless pipes, but there are strict requirements on the steel grades used to manufacture steel pipes. According to the temperature of use, it is divided into two types: general boiler tubes and high-pressure boiler tubes.

For hot-rolled thin-walled seamless pipes with rough product defects, inspection before rolling is to find surface abnormalities. However, after grinding and pickling, it was found that there were "dark spots" on the surface of the tube blank. Metallographic examination showed that the dark spots corresponded to coarse grains.

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.