2.3 Dominated by cold rolling, cold-draw supplemented  

Cold stainless steel tube tends to adopt a cold rolling based, cold-draw supplemented by the joint production process, cold rolling mill, cold-drawing machines use high-speed, high precision, long stroking, multi-line direction. The Stainless steel tube is 50% to 80% completed within the cold process. Therefore, the development of cold process equipment has been given more attention. There are basically three types of cold working processes, the drawing process, cold rolling, and the cold drawing of a joint process. In most cases, the cold-rolled joint of a drawing process, and cold rolling are supplemented by the processing method. The modern cold rolling mill is expected to achieve a reduced diameter, and reduced wall volume, an 80% rolling reduction has already been completed in the cold rolling mill. The cold wall use has been supplemented by drawing specifications and control changes in diameter to meet the requirements of different varieties and specifications.  

The drawing process of a joint production of cold rolled advantages are: good quality steel pipe, cold rolled steel pipe wall thickness accuracy and surface quality with high precision, cold-drawn to ensure the pipe diameter; cold period is short, to reduce intermediate de-greasing, heat treatment, necking, Jiao Direct processes, energy conservation, reduced metal consumption; shortage can be used to produce small diameter steel pipe tube, simplified types of raw material specifications.  

Currently, the world's cold-rolled, cold-drawn process technology and equipment level has been greatly developed. Cold rolling forward speed, long travel, ring larvae L-type, high-precision direction, this mill is characterized by: 

1) Inertia force and inertia torque with vertical balance mechanism, the number of mills has increased; 

2) The ring groove, the length of deformation zone of rolling mill longer than the 70% short stroke, improve the uniformity of rolling, sending has increased; 

3) Using a long tube, pipe shortage of raw materials increased length l2 ~ 15m, can produce long steel pipe, improve mill efficiency, effective utilization coefficient of rolling over up to 80%; 

4) Mandrel and the best use of parabolic curved groove, metal deformation and reasonable, tool can be used for a long period of time.

These characteristics make cold rolling mill production capacity and greatly enhance the production of stainless steel products, precision cold drawn tube of the machine structure is still the mainly used drawing machine,  a smaller amount continue to use the hydraulic drawing machine. The multi-line, high-speed, automatic drawing machine is the current direction of development.