Precision stainless steel pipes are very distinctive in terms of model specifications and appearance performance. First of all, the thicker the wall of this type of stainless steel pipe, the higher its cost-effectiveness and practicality, while the thinner the wall, the greater the processing cost. 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, and the fixed length cost is relatively expensive. Pit and black spots are easy to appear on the inner and outer surfaces of the pipe and are not easy to remove. In addition, the inspection and shaping of precision stainless steel thick-walled pipes must be processed offline. Therefore, stainless steel pipes show sufficient superiority in the field of high-pressure and high-strength mechanical structural materials.
According to the continuous rolling process, stainless steel pipes are mainly divided into hot-rolled, hot-extruded, and cold-drawn (rolled) stainless steel pipes. According to the differences in the metallographic structure of stainless steel, they mainly include semi-ferrite 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 GB14975-94 “Stainless Steel Seamless Pipes”. The general length (indefinite length) of precision stainless steel thick-walled pipes is 1.5-10m for hot-rolled steel pipes and 1m or more for hot-extruded steel pipes. 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 types of hot-rolled (hot-extruded) stainless steel pipes with a diameter of 54-480mm, and about 36 types with a wall thickness of 4.5-45mm. There are 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.
The inner and outer surfaces of the thick-walled precision stainless steel pipes shall not have defects such as cracks, folds, cracks, cracks, rolling, delamination, and scarring. Such defects need to be completely removed (unless they are specially used for machining), and the wall thickness and outer diameter of the stainless steel pipe wall cannot exceed the negative deviation after removal. Some minor surface defects that do not exceed the allowable negative deviation do not need to be removed.
The allowable depth of stainless steel straight lines is also required. Hot-rolled, hot-extruded steel pipes, stainless steel pipes with a diameter of less than or equal to 140mm and not more than 5% of the nominal wall thickness, the depth is less than or equal to 0.5mm, cold-drawn (rolled) stainless steel pipes are not greater than 4% of the nominal wall thickness, and the depth is less than or equal to 0.3mm.
Finally, it should be noted that the thick-walled precision stainless steel pipes need to be cut into right angles at both ends before application, and the burrs in the pipe wall need to be removed.
Post time: Sep-12-2024