Seamless steel pipes are commonly used to measure the hardness of Brinell, Rockwell, and Vickers.

According to the composition, it can be divided into Cr system (SUS400), Cr-Ni system (SUS300), Cr-Mn-Ni (SUS200) and precipitation hardening system (SUS600).

The temperature coefficient is the rate at which the physical properties of a material change with temperature.

Pipe roughness, mechanical terms. In mechanics, roughness refers to the micro-geometric characteristics of small pitches and peaks and valleys on the processed surface.

Seamless steel pipes are rolled with solid pipe blanks after piercing. 1. Manufacturing method: According to different production methods, it can be divided into hot rolled tube, cold rolled tube, cold drawn tube, extruded tube, etc. a. Hot rolled seamless tubes are generally produced on automatic tube rolling units. After inspection and removal of surface defects, the solid tube billet is cut t...

Welding procedure：round tube billet → heating → perforation → three-roller cross-rolling,  continuous rolling or extrusion → tube removal → sizing (or reduced diameter) → cooling → straightening → hydraulic test (or flaw detection) → marking.