Features of stainless steel seamless pipe:
First, the thicker the wall thickness of the product, the more economical and practical it is, and the thinner the wall thickness, the higher the processing cost. Secondly, the process of this product determines its limited performance. Generally, the precision of seamless steel pipe is low: uneven wall thickness, low brightness on the inner and outer surfaces of the pipe, high cut-to-length cost, and pits and black spots on the inner and outer surfaces are not easy to remove; Third, its detection and shaping must be done off-line. Therefore, it shows its advantages in high pressure, high strength and mechanical structure materials.
Types of stainless steel pipes:
Rolling methods include hot rolling, hot extrusion and cold drawing (rolling) of stainless steel pipes.
According to the different metallographic structure of stainless steel, it can be divided into semi-ferritic semi-martensitic stainless steel tubes, martensitic stainless steel tubes, austenitic stainless steel tubes and austenitic-ferritic stainless steel tubes.
Specification and appearance quality of stainless steel pipes;
A According to GB 14975-94 Seamless Stainless Steel Pipe, the usual steel pipe length (indefinite length) is 1.5 ~ 10m for hot-rolled steel pipe and 1m for hot-extruded steel pipe. The wall thickness of cold-drawn (rolled) steel pipe is 0.5 ~1.0 ~ 7m; ， 1.0 ~ 7m； If the wall thickness is greater than 1.0mm, it is 1.5 ~ 8m.
B, 45 kinds of hot-rolled (hot-extruded) steel pipes with diameters of 54 ~ 480mm * * * * 36 species with wall thickness of 4.5 ~ 45 mm * * *. 65 kinds of cold-drawn (rolled) steel pipes with diameters of 6 ~ 200mm * * *; The wall thickness is 0.5 ~ 2 1mm * * * 39 kinds.
C. There shall be no cracks, folds, cracks, cracks, rolling injuries, delamination and scarring on the inner and outer surfaces of steel pipes. These defects shall be completely removed (except for pipes used for mechanical processing), and the thickness and outer diameter of the removed rear wall shall not exceed negative deviation. Other minor surface defects not exceeding the allowable negative deviation may not be removed.
D, the allowable depth of the straight line. Hot-rolled and hot-extruded steel pipes with a diameter less than or equal to 140mm should not be greater than 5% of the nominal wall thickness, and the maximum depth should not be greater than 0.5mm；; Cold-drawn (rolled) steel pipes should not be greater than 4% of the nominal wall thickness, and the maximum depth should not be greater than 0.3 mm. ..
Precision pipe is a kind of seamless steel pipe with high precision and high brightness produced by cold drawing or cold rolling process. Its inner and outer diameters can be accurate to less than 0.2 mm, and it is light in weight while ensuring bending and torsion strength, so it is widely used to manufacture precision mechanical parts and engineering structures.