Precision
stainless steel pipes are very characteristic in terms of model specifications and appearance performance. First of all, the thicker the pipe wall of this type of stainless steel pipe, the higher the cost performance and practicability, and the thinner the pipe wall, the higher the processing cost. In addition, the performance limitations of stainless steel pipes depend on the processing technology. Generally, the precision of seamless steel pipes is low, and the thickness of the pipe wall is not uniform. Pockmarks and black spots are prone to appear and are not easy to remove. In addition, the detection and shaping of precision stainless steel thick-walled pipes must be processed offline. Therefore, stainless steel pipes show sufficient advantages in the field of high-pressure, high-strength mechanical structural materials.
Stainless steel pipes are mainly divided into hot rolling, hot extrusion, and cold drawn (rolled) stainless steel pipes according to the rolling process. According to the differences in the metallographic structure of stainless steel, it mainly includes semi-ferritic and semi-martensitic stainless steel pipes, martensitic stainless steel pipes, austenitic stainless steel pipes, and austenitic-ferritic stainless steel pipes.
According to the specifications, the specifications of stainless steel pipes are mainly based on the provisions of GB14975-94 "Stainless Steel Seamless Steel Tubes", of which the general length (indefinite length) of precision stainless steel thick-walled pipes is 1.5-10m for hot-rolled steel pipes, and hot-extruded steel pipes are greater than or equal to 1m. The wall thickness of cold drawn (rolled) stainless steel pipe is 0.5-1.0mm, and the length is 1.0-7m; the wall thickness is greater than 1.0mm, and the length is 1.5-8m.
There are about 45 types of hot-rolled (hot-extruded) stainless steel pipes with a diameter of 54-480mm, and a total of about 36 types with a wall thickness of 4.5-45mm. There are a total of 65 types of cold drawn (rolled) stainless steel pipes with a diameter of 6-200mm and a total of 39 types with a wall thickness of 0.5-21mm.
Defects such as cracks, folds, cracks, cracks, folds, delaminations, and scarring should not appear on the inner and outer surfaces of the precision stainless steel thick-walled pipes. Such defects need to be completely removed (unless they are specially used for machining), And after the stainless steel pipe wall is removed, the wall thickness and the outer diameter cannot exceed the negative deviation. As long as some minor surface defects do not exceed the allowable negative deviation, it is not necessary to remove them.
The allowable depth of stainless steel straights is also required. Hot-rolled, hot-extruded steel pipes, stainless steel pipes with a diameter of less than or equal to 140mm and not greater than 5% of the nominal wall thickness, with a depth of less than or equal to 0.5mm, and cold-drawn (rolled) stainless steel pipes not greater than 4% of the nominal wall thickness, with a depth of less than or equal to 0.5mm Equal to 0.3mm.
The last thing to note is that the precision stainless steel thick-walled pipe needs to be cut at right angles at both ends and the burrs in the pipe wall should be removed before application.
