Type of stainless steel tube:
The rolling method is divided into hot rolling, hot extrusion and cold drawing (rolling) stainless steel tubes.
According to the stainless steel metallographic structure, it is divided into semi-ferritic semi-Martensitic stainless steel pipes, martensitic stainless steel pipes, austenitic stainless steel pipes, austenitic-ferritic iron stainless steel pipes.
Stainless steel tube specifications and appearance quality:
A. According to GB14975-94 "stainless steel seamless steel pipe", the normal length of steel pipe (indefinite) hot-rolled steel pipe is 1.5~10m, and the hot-extruded steel pipe is equal to or greater than 1m. Cold drawn (rolled) steel pipe wall thickness of 0.5 ~ 1.0mm, 1.0 ~ 7m; wall thickness
greater than 1.0mm, 1.5 ~ 8m.
B. There are 45 kinds of hot-rolled (hot-extruded) steel pipes with a diameter of 54-480 mm; a total of 36 kinds of wall thicknesses of 4.5-45 mm. There are 65 kinds of cold drawn (rolled) steel pipes with a diameter of 6 to 200 mm, and 39 kinds of wall thicknesses of 0.5 to 21 mm.
C. There shall be no cracks, folds, cracks, cracks, rolling, separation and crusting defects on the inner and outer surfaces of the steel pipe. These defects shall be completely removed (except for mechanical processing pipes), and the wall thickness and outer wall shall not be removed after removal. The diameter exceeds the negative deviation. Other minor surface defects that do not exceed the allowable negative deviation may not be removed.
D. Straight road allows depth. Hot-rolled, hot-extruded steel pipe, diameter less than or equal to 140mm is not more than 5% of the nominal wall thickness, the maximum depth is not more than 0.5mm; cold drawn (rolled) steel pipe is not more than 4% of the nominal wall thickness, the maximum depth is
not more than 0.3 Mm.
E. Both ends of the steel pipe should be cut at right angles and the burrs should be removed.
Stainless steel seamless steel pipe manufacturing process:
1. Hot rolling (extrusion seamless steel pipe): round billet → heating → perforation → three-roll cross-rolling, continuous rolling or extrusion → pipe removal → sizing (or reducing diameter) → cooling → straightening → hydraulic test (or flaw detection) → mark → warehousing.
2. Cold drawn (rolled) seamless steel pipe: round tube blank → heating → perforation → head → annealing → pickling → oiling (copper plating) → multi-pass cold drawing (cold rolling) → blank tube → heat treatment → straightening →Hydraulic pressure test (inspection) → mark → storage.