Cold drawn seamless steel pipe production process

What is cold drawn seamless steel pipe?

Cold-drawn seamless steel pipe is a kind of precision seamless pipe with high precision and good surface finish used in mechanical structures and hydraulic equipment. Cold-drawn steel pipe is a kind of steel pipe, that is, it is classified according to different production processes. The difference For hot rolled (expanded) pipe. It is processed through multiple passes of cold drawing during the diameter expansion process of the raw tube blank or raw material pipe, usually on a 0.5 to 100T single-chain or double-chain cold drawing machine.

Raw material preparation:

The raw material of cold drawn seamless steel pipe is steel ingot or steel rod, and its composition should comply with the corresponding ASTM A252 standard. Steel needs to be surface treated so that its finish and surface roughness are controlled. Cold-drawn seamless steel pipes are characterized by high precision, usually around 20 wires, while hot-rolled seamless steel pipes have a precision of around 100 wires. Therefore, cold-drawn seamless steel pipes are the first choice for mechanical processing manufacturing and parts manufacturing. High-quality materials: Generally made of high-quality carbon structural steel such as No. 10, No. 20, No. 35, and No. 45 steel to ensure chemical composition and mechanical properties. Cold-drawn seamless steel pipes have good appearance quality, and there must be no defects such as cracks, folds, roll folds, separation layers, hair lines, and scars on the inner and outer surfaces.

Cold drawn seamless steel pipe production process

Preheat:Steel needs to be cold drawn multiple times during the cold drawing process. In order to avoid steel pipe deformation and quality problems caused by deformation and strain caused by the cold drawing process, the steel needs to be preheated. The preheating temperature is generally around 600°C and the time is about 30 minutes.

Cutting:The preheated steel is cut through machinery and equipment to obtain steel pipe blanks of appropriate size.

Pickling:Put the steel pipe blank into the acid solution, and use chemical reactions to remove rust, oxide scale and other impurities on its surface, making the steel surface cleaner and reducing the damage to the steel pipe caused by cold drawing processing.

welding:For long steel pipes, in order to reduce waste, you can use the principle of high-frequency induction heating to cut some shorter steel pipe blanks in the middle of a section of steel, and then weld these shorter steel pipe blanks to obtain long steel pipe pipes.

Cold drawing processing: Use a cold drawing machine to process the steel pipe blank, and slowly deform the steel through the drilling die until it becomes a seamless steel pipe. During the cold drawing process, attention should be paid to controlling parameters such as temperature, perforation, and drawing speed to ensure the stability of steel pipe quality.

Heat treatment:After the cold-drawn seamless steel pipe process is completed, heat treatment can improve its mechanical properties and increase its ductility and toughness. The heat treatment temperature is generally around 800°C and the time is about 1 hour.

Surface treatment:The surface of seamless steel pipes needs to undergo rust removal, grinding, painting and other treatments to achieve the effects of beauty, corrosion resistance and reduced surface roughness.

The above are the main steps in the production process of cold drawn seamless steel pipe. Each step requires strict control of the process flow and involves issues such as accuracy requirements of machinery and equipment. Only by strictly implementing production operating procedures and quality control standards can high-quality seamless steel pipes be produced.