What is cold treatment of stainless steel pipes?

Both stainless steel seamless steel pipes and stainless steel welded steel pipes can be cold processed - cold rolled and cold drawn to meet higher requirements for cold processed products.

Features of cold processing of stainless steel pipes:
1. Improve the surface and improve the corrosion resistance due to the improvement of surface finish.
2. Further improve the dimensional accuracy of seamless pipes. After cold rolling or cold drawing with a mandrel, not only the outer diameter accuracy can be improved, but also the dimensional accuracy of the wall thickness can be improved.
3. Seamless steel pipes with smaller diameters and thinner walls can be produced.
4. Combined with solid solution heat treatment after cold deformation, the mechanical properties can be improved.
5. Can produce non-standard stainless steel seamless pipes of special sizes and cross-sections

Cold working process of stainless steel pipe
1. Cold drawing process:
The diameter of the cold drawn pipe is heated at room temperature or the end is reduced, the surface is pickled to remove oxide scale, and lubricant is applied for cold drawing. There are three methods of cold drawing. Plugs that are cold drawn on the finished inner diameter are called plug cold drawing. Cold drawing with a mandrel that is the same length as the tube is called cold drawing with a mandrel or free cold drawing without a mandrel. The inner wall of the cold-drawn mandrel is smooth, which can achieve a larger deformation ratio and is suitable for cold-drawing long stainless steel pipes.
Cold drawing machines can be chain, hydraulic or hydraulic. Chain cold drawing can draw two or more steel pipes at one time. In order to reduce the wear between the cold drawn tube and the mold, the quality of the lubricant is very important to improve efficiency. Pickling is usually used to remove surface oxide scale, and then lubricant is applied for cold drawing.
The main disadvantages of cold drawn stainless steel pipe are:
The amount of deformation in each pass is small, so there are many processing passes and the production cycle is long; the metal consumption is large. The inner and outer surface finish of the tube is poor.

2. Cold rolling process:
Cold-rolled stainless steel pipe is a cold processing method that uses two rollers to gradually reduce the rolling pass along the circumference, and uses a mandrel with a slope to roll back and forth, which is called the cold Pilger method. Three-roll cold rolling mills can also be used.
The biggest disadvantage of cold-rolled pipes is that they are hard, that is, they have a large yield coefficient and are not suitable for expansion and bending, so they require thermal solidification (annealing).

Stainless steel seamless pipe：https://www.eastern-steels.com/newsdetail/stainless-steel-seamless-pipe-vs-carbon-steel-seamless-pipe.html