Stainless pipe is a kind of hollow long round steel, which is mainly used in industrial transportation pipelines and mechanical structural components such as petroleum, chemical industry, medical treatment, food, light industry, mechanical instrument and so on. In addition, when the bending and torsional strength are the same, the weight is lighter, so it is also widely used in the manufacture of mechanical parts and engineering structures. It is also commonly used as furniture and kitchenware.
Stainless tubes and pipes are divided by materials into ordinary carbon steel pipes, high-quality carbon structural steel pipes, alloy structural pipes, alloy steel pipes, bearing steel pipes, stainless steel pipes, and bimetallic composite pipes, plated and coated pipes for saving precious metals and meeting special requirements. There are many kinds of stainless pipes, different uses, different technical requirements and different production methods.
Stainless tubing is an economical section steel and an important product in the steel industry. It can be widely used in living decoration and industry. Many people in the market use it to make stair handrails, window guards, railings, furniture, etc. Two common materials are 201 and 304.
(1) Die forging
For socket-welded and threaded tee, cross, elbow and other small-sized pipe fittings, the shape is relatively complex and should be manufactured by die forging. The blanks used for die forging should be rolled profiles such as bars, thick-walled stainless pipes, or plates. When using stainless tubes and pipes as raw materials, the ingots should be rolled into bars in advance or used as blanks after forging to eliminate segregation, porosity and other defects in the ingots. After the billet is heated, it is put into the die for forging, and the pressure makes the metal flow to fill the die cavity; if the forged billet has flash, it needs to go through the step of flushing the remaining flash to complete the forging work.
(2) Free forging
For stainless tubing fittings with special shapes or stainless tubes and pipes that are not suitable for die forging, they can be manufactured by free forging process. In free forging, the general shape of the pipe fittings should be forged, such as a tee, its parts should be forged.
For some stainless pipes with cylindrical shape, they can be formed by direct cutting of bars or thick-walled pipes, such as double socket pipe clamps, unions, etc. During processing, the fiber flow direction of the metal material should be roughly parallel to the axial direction of the stainless tubing. For tees, crosses, and elbows, direct cutting of bars is not allowed.