Cold rolling means that metal materials are rolled in low temperature. Before cold drawing, we will do acid-pickling, phosphating and saponification for hollow billet. Acid-pickling, also named as acid cleaning, is a method of cleaning the metal surface and removing the oxide film on metal surface. Phosphating, also known as phosphorization, is a process that can form phosphate protective coating on the metal surface. Saponification reacting with the phosphate film can produce a metal soap film. It plays the role of lubricant in the cold rolling process. With large rolling force, cold drawing can make steel tubes with high dimension precision.
Cold Rolling Unit We possess one Φ76 punching pipe mill, four sets of Φ50 punching machines and 28 sets of 5-120 ton cold drawing machine configured with straightening machine and inspection machine.
Technological Process of Cold Rolling Clod-Rolled Precision Seamless Steel Tube:
Round Pipe Billet-Inspection-Cutting Off-Heating-Punching-Tube Rolling-Cooling-Inspection- Acid-pickling, Lubrication- Rolled by Cold Drawing Machine-Oxygen-free Heat Treatment-Precision Straightening-Top Cutting and Chamfering-Non-destructive Inspection-Rust Prevention, Packaging-Weighing-Put into Storage
Features The main feature of cold rolling is low processing temperature. It also has the following merits:
Cold rolled steel tubes are of high dimension precision and uniform thickness.
Cold rolled steel pipes have high-quality surface. There is no hard spot and oxide scale defect on cold-rolled steel pipes.
After cold drawing, our pipes acquire good mechanical properties and processing properties, such as high strength, low yield limit, good deep drawing properties, etc.
Technological Process of Hot Rolling Round Pipe Billet → Heating → Punching → Precision Tube Rolling Unit → Reheating → Sizing Mill and Tension Reducing Mill → Sampling Inspection → Cooling
Thermal rolling can obviously reduce energy consumption and reduce production cost. After this process, our steel pipes acquire high plasticity and they are not easy to deform.
This processing technology can improve the processing properties of seamless steel tubes and alloy. Hot rolling can also reduce or eliminate casting flaws.
Thermal rolling can produce steel pipes with large diameter with fast production speed and high production efficiency.