How are seamless steel pipes made?

TAGS: steel | pipes | process |

Seamless steel pipe is a continuous manufacturing process, and its manufacturing process usually includes the following steps:

Raw material preparation: First of all, it is necessary to prepare raw materials for the manufacture of seamless steel pipes. Generally, steel ingots or hot-rolled coils are used as raw materials. These raw materials are processed into blanks of required size and shape after cutting and straightening.

Tube body pretreatment: The billet is subjected to multi-pass cleaning, degreasing, pickling, water washing and other pretreatment processes to remove surface impurities and oxide scales, while increasing surface roughness, which is beneficial to subsequent processing.

Continuous hot rolling: the pretreated billet is heated to a high temperature state, and then rolled by a multi-roller continuous rolling mill, so that the billet becomes a cylindrical pipe with a certain length and wall thickness during the rolling process. During this process, parameters such as heating temperature, rolling pressure and speed should be controlled to ensure the stability and consistency of pipe quality.

Cooling and straightening: After rolling, the steel pipe should be cooled and straightened to eliminate internal stress and shape deformation, and to make the inner and outer surfaces of the pipe smooth and smooth. Cooling methods include water quenching, oil quenching, air cooling, etc., and straightening is to adjust the bending and straightness of the pipe through mechanical force or hydraulic pressure.

Inspection and packaging: Finally, quality inspections are carried out on the manufactured seamless steel pipes, such as ultrasonic flaw detection, magnetic particle inspection, eddy current inspection, etc., to ensure that they meet relevant standards and requirements. Qualified steel pipes will be packaged into finished products of different specifications and forms, and sold at the factory or stored for later use.

The steel types and grades used for seamless steel pipes are determined according to specific application scenarios and requirements, generally including carbon structural steel, low-alloy high-strength steel, stainless steel, etc. Common grades of seamless steel pipes include 20#, 35#, 45#, 40Cr, 20CrMoV, etc.

Application scenario:

Seamless steel pipes are widely used in petrochemical, aerospace, automobile manufacturing, building structures, machinery manufacturing and other fields. Specific application scenarios include transporting high-temperature and high-pressure gas or liquid, manufacturing large-diameter pipelines, and manufacturing mechanical parts.