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Do you know the specifications and appearance quality of Seamless Steel Pipe?

Dec. 26, 2019

Seamless Steel Pipe is a long strip of steel with a hollow section and no seams around it. The thicker the wall thickness of the product, the more economical and practical it is. The thinner the wall thickness, the higher the processing cost.

Seamless Steel Pipe

Seamless Steel Pipe

The technology of this product determines its limited performance. Generally, the seamless steel pipe has low accuracy: uneven wall thickness, low brightness on the inside and outside of the tube, high scale costs, and pits and black spots on the inside and outside. Shaping must be processed offline. Therefore, it shows its superiority in terms of high pressure, high strength, and mechanical structural materials.

According to the rolling method, it is divided into hot rolling, hot extrusion and cold drawing (rolling) stainless steel pipe.

According to the stainless steel metallographic structure, it is divided into semi-ferritic and semi-martensitic stainless steel seamless pipes, martensitic stainless steel seamless pipes, austenitic stainless steel seamless pipes, austenitic-ferritic stainless steel seamless pipes, etc.

As a Seamless Steel Pipe Supplier, share with you the specifications and appearance quality.

A. According to regulations, steel pipes usually have a length of 1.5 to 10 m for hot-rolled steel pipes, and hot-extruded steel pipes are equal to and larger than 1 m. For cold drawn (rolled) steel pipes with a wall thickness of 0.5 to 1.0 mm, 1.0 to 7 m; for wall thicknesses greater than 1.0 mm, 1.5 to 8 m.

B. There are 45 kinds of hot-rolled (hot-extruded) steel pipes with a diameter of 54 to 480mm; 36 kinds of wall thicknesses of 4.5 to 45mm. There are 65 types of cold drawn (rolled) steel pipes with a diameter of 6 to 200mm; 39 types of wall thicknesses of 0.5 to 21mm.

C. There must be no cracks, folds, cracks, cracks, creases, delaminations, and scars on the inner and outer surfaces of the steel pipe. These defects should be completely removed (except for pipes for mechanical processing). After removal, the wall thickness and external Diameter exceeds the negative deviation. Other minor surface defects that do not exceed the allowable negative deviation may not be removed.

D. Straight allowable depth. Hot-rolled, hot-extruded steel pipes, diameters less than or equal to 140mm, not more than 5% of the nominal wall thickness, and the maximum depth is not more than 0.5mm; cold-drawn (rolled) steel pipes are not more than 4% of the nominal wall thickness and the maximum depth is not more than 0.3 mm.

E. Both ends of the steel pipe should be cut at right angles, and burrs should be removed.

The manufacturing process of stainless steel seamless pipe

1. Hot rolling (extruded seamless steel pipe): round pipe billet → heating → perforation → three-roll oblique rolling, continuous rolling or extrusion → stripping → sizing (or reducing) → cooling → straightening → hydraulic test (Or flaw detection) → mark → storage

The raw material for rolling seamless pipes is round pipe blanks. Round pipe blanks are cut by a cutting machine into billets with a length of about 1 meter and then sent to the furnace for heating by a conveyor belt. The billets are sent to a furnace for heating to a temperature of about 1200 degrees Celsius. The fuel is hydrogen or acetylene. Furnace temperature control is a key issue. After the round tube billet is discharged, it is pierced through a pressure perforator. Generally, the more common punching machine is a tapered roller punching machine. This punching machine has high production efficiency, good product quality, large perforation diameter expansion, and can wear a variety of steel types. After perforating, the round tube blank is successively rolled by three rolls, continuously rolled or extruded. After extrusion, sizing is required. The sizing machine rotates into the steel embryo to drill holes at high speed through a conical drill to form a steel pipe. Our company also has Alloy Seamless Steel Tubes on sale, welcome to consult.


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