Stainless steel pipe

Seamless steel pipe is made of the whole round steel perforation, no weld on the surface, called seamless steel pipe. According to the production method, seamless steel pipe can be divided into hot rolled seamless steel pipe, cold rolled seamless steel pipe, cold pulled seamless steel pipe, extrusion seamless steel pipe, pipe jacking, etc. According to the section shape, the seamless steel pipe is divided into two round shapes and different shapes, and the abnormal tube has many complex shapes: square shape, oval shape, triangle shape, hexagonal shape, melon seed shape, star shape and wing belt tube. Max. diameter up to 900mm, Min. diameter is 4mm. According to the use, there are thick-wall seamless steel pipe and thin-wall seamless steel pipe. Seamless steel pipe is mainly used as petroleum geological drilling pipe and petrochemical Cracking, boiler, bearing pipes and high precision structural steel pipes for vehicles, tractors and aviation.

Classification

1. No seam steel pipe along the periphery of its cross-section. According to the different production methods, it is divided into hot rolled pipe, cold rolled pipe, cold pull pipe, extrusion pipe, pipe jacking, etc., with their own process provisions.

2. materials include ordinary and high quality carbon structural steel (Q215-A~Q275-A and 10~50 steel), low alloy steel (09MnV, 16Mn, etc.), alloy steel, no rust acid resistant steel, etc.

3. is divided into general use (for water transport, gas pipeline and structural parts, mechanical parts) and special (for boiler, geological exploration, bearings, acid resistance, etc.).

Use

Seamless steel pipes are widely used.

1, Seamless steel pipes are rolled by ordinary carbon structural steel, low alloy structural steel or alloy structural steel, with the most yield, and are mainly used as pipes or structural parts conveying fluid.

2, is supplied into three categories depending to purpose:

a, is supplied by chemical composition and mechanical properties;

b, is supplied by mechanical properties;

c,is supplied by the hydrostatic test. Steel pipes supplied by Class a, b are also hydrodynamically tested if used to withstand liquid pressure.

3, has various seamless pipes for boiler, chemical power, seamless steel pipe for geology and seamless pipe for petroleum.

Seamless steel pipes have hollow sections used for fluid delivery, such as oil, gas, gas, water and certain solid materials. Compared with solid steel products such as round steel, when the bending and torsion strength is the same, it is an economic section steel.

It is widely used in the manufacturing of structural parts and mechanical parts, such as oil drilling rod, automobile drive shaft, bicycle frame, construction of steel scaffolding and other ring parts, can improve the material utilization rate, simplify the manufacturing process, save materials and processing hours, has been widely used steel pipe to manufacture.

Production process

Main production process of ① hot-rolled seamless steel pipe (△ main inspection procedure):

Pipe blank preparation and inspection △ → pipe billet heating → perforation → rolled pipe → steel pipe → reheating → fixed (minus) diameter → heat treatment △ → finished pipe straightening → finishing → inspection △ (nondestructive, physical and chemical, bench inspection) → storage

Main production process of ② cold-rolled (pulled-out) seamless steel pipe:

Billet preparation → pickling lubrication → cold rolling (pull out) → heat treatment → straightening → finishing → inspection

Mechanical performance index

① tensile strength (σb)

② yield point (σs)

③ post-break elongation ((σ))

④ cross-section shrinkage rate (ψ)

⑤ hardness index