Stainless steel seamless pipe manufacturing process

Stainless steel seamless pipe manufacturing process is a complex and fine process, mainly including raw material preparation, perforation, rolling, heat treatment, pickling, cold drawing or cold rolling, cutting, inspection and other links. The following is a detailed explanation of this manufacturing process:

First, raw material preparation

High-quality stainless steel billets are selected as raw materials to ensure that the chemical composition and mechanical properties of the steel pipe meet the requirements.

The raw materials are cut and processed by the cutting machine with a growth of about 1 meter, and are stacked according to the steel grade, furnace number, production batch number and specifications.

Second, heating and perforation

The round tube billet is heated in the furnace, the temperature is about 1200 degrees Celsius, the fuel is hydrogen or acetylene, and the temperature control in the furnace is the key.

After heating, the round tube blank is perforated by a pressure piercing machine to form a capillary tube. Perforation is a key step in manufacturing seamless steel pipes.

Third, rolling

The tube is rolled or cold-drawn/cold-rolled in multiple passes, gradually reaching the required size and accuracy. In this process, the temperature, deformation and other parameters are strictly controlled to ensure the mechanical properties and surface quality of the pipe.

The rolling methods include hot rolling, cold drawing and cold rolling. Hot rolling is the stainless steel seamless pipe produced by the broaching machine after annealing the blank and reducing the wall. Cold drawing is to use the cold drawing machine to expand and reduce the wall of the steel pipe without heating. In cold rolling, there is a fixed mold outside the pipe and a fixed mandrel in the hole of the pipe, which thinens the thickness of the pipe from the outside to the inside.

Fourth, heat treatment

Heat treatment is an important link to improve the performance of the pipe. Through annealing, solution treatment and other processes, the processing stress is eliminated, the structure is adjusted, and the corrosion resistance and mechanical properties of the stainless steel seamless pipe are improved.

Vacuum bright annealing is a kind of anaerobic annealing, which can reduce hardness, eliminate magnetism, improve corrosion resistance, and restore metallographic structure.

Fifth, pickling and passivation

Pickling is mainly used to remove the oxide and rust on the surface of the steel pipe to improve the finish and corrosion resistance of the steel pipe surface.

Passivation is to form an oxide protective film after pickling to further enhance the corrosion resistance of the steel pipe.

Sixth, straightening and cutting

Straightening is to make the steel pipe reach the required straightness. Commonly used straightening equipment includes vertical straightener, horizontal straightener and vertical hydraulic press.

Cutting is to cut the straightened steel pipe to a specified length to meet customer needs.

Seventh, inspection and packaging

The process of finished product inspection and test is mainly for surface inspection, vortex exploration, superexploration, water pressure and air pressure detection to ensure that the surface of the steel pipe has no defects, no loopholes, no internal and external cracking, and no water leakage and air leakage.

Qualified steel pipes enter the finished product packaging area for packaging. Materials such as hole caps, plastic bags, snakeskin cloth, wooden boards, and stainless steel belts are used for packaging to prevent collisions caused by contact between steel pipes during transportation.

In summary, the manufacturing process of stainless steel seamless pipes requires rigorous operation and fine technical support. Through this series of complex processes, high-quality, high-performance stainless steel seamless pipes can be manufactured, which are widely used in petroleum, chemical, pharmaceutical, food, machinery manufacturing, construction and other fields.