Stainless steel pipes are very distinctive 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 its cost performance and practicality will be. The thinner the pipe wall, the greater the processing cost will be. In addition, the performance limitations of stainless steel pipes depend on the processing technology. Usually, the precision of seamless steel pipes is low, and the thickness of the pipe wall is uneven, the brightness of the inner and outer surfaces of the pipe is low, the cost of cutting to length is relatively expensive, and the inner and outer surfaces of the pipe are Pockets and black spots are prone to appear and are difficult to remove. In addition, the detection and shaping of precision stainless steel thick-walled tubes 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-rolled, hot-extruded, 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, austenitic-ferritic stainless steel pipes, etc.
According to the specifications, the specifications of stainless steel pipes are mainly based on the regulations of GB14975-94 "Stainless Steel Seamless Steel Pipes". The general length (indeterminate length) of thick-walled precision stainless steel pipes is hot-rolled steel pipes 1.5-10m, and hot-extruded steel pipes are greater than or equal to 1m. The wall thickness of cold-drawn (rolled) stainless steel pipes 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 models of hot-rolled (hot-extruded) stainless steel pipes with a diameter of 54-480mm and a total of about 36 models 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 of wall thicknesses of 0.5-21mm.
Defects such as cracks, folds, cracks, cracks, folds, delamination, and scarring must not appear on the inner and outer surfaces of thick-walled precision stainless steel tubes. Such defects need to be completely removed (unless they are specifically used for mechanical processing). After cleaning the stainless steel pipe wall, the wall thickness and outer diameter cannot exceed the negative deviation. Some minor surface defects do not need to be removed as long as they do not exceed the allowable negative deviation.
The allowable depth of stainless steel straight tracks also has requirements. Hot-rolled, hot-extruded steel pipes, stainless steel pipes with a diameter less than or equal to 140mm and no greater than 5% of the nominal wall thickness, a depth less than or equal to 0.5mm, cold-drawn (rolled) stainless steel pipes no greater than 4% of the nominal wall thickness, a depth less than Equal to 0.3mm.
The last thing to note is that before application, thick-walled precision stainless steel pipes need to be cut at right angles at both ends and the burrs in the pipe wall removed.