Stainless Steel Seamless Pipe

Stainless steel seamless pipe is a kind of long steel with a hollow section and no joints around it. The thicker the wall thickness of the product, the more economical and practical it is, the thinner the wall thickness, its processing costs will rise significantly.

The process of the product determines its limited performance, the general precision of seamless steel pipe is low: the wall thickness is not uniform, the external brightness of the tube is low, the measurement cost is high, and the internal surface is not easy to remove pockmarks and black spots; Its detection and shaping must be handled offline. Therefore, it embodies its superiority in high pressure, high strength and mechanical structure materials.

seamless stainless steel tubing-kind

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

According to the different metallographic structure of stainless steel, it is divided into half ferritic half martensitic stainless steel seamless pipe, martensitic stainless steel seamless pipe, austenitic stainless steel seamless pipe, and austenitic ferritic stainless steel seamless pipe.

Specifications and appearance quality

A, according to GB14975-2002 "Stainless steel seamless steel pipe" provisions, steel pipe usually length (variable length) hot rolled steel pipe 1.5 ~ 10m, hot extrusion steel pipe is equal to and greater than 1m. Cold drawn (rolled) steel pipe wall thickness of 0.5 ~ 1.0mm, 1.0 ~ 7m; If the wall thickness is greater than 1.0mm, 1.5 ~ 8m.

B, hot rolled (hot extrusion) steel pipe diameter 54 ~ 480mm a total of 45 kinds; There are 36 kinds of wall thickness 4.5-45mm. Cold-drawn (rolled) steel pipe diameter of 6 ~ 200mm a total of 65 kinds; There are 39 kinds of wall thickness from 0.5 to 21mm.

C, the inner and outer surface of the steel pipe shall not have cracks, folding, cracking, cracking, rolling, separating and scarring defects, these defects should be completely removed (except for the pipe for mechanical processing), and the wall thickness and outer diameter shall not exceed the negative deviation after removal. Other minor surface defects that do not exceed the allowable negative deviation may not be removed.

D, the allowable depth of the straight. Hot rolled, hot extruded steel pipe, diameter less than or equal to 140mm is not greater than 5% of the nominal wall thickness, the maximum depth is not greater than 0.5mm; The cold-drawn (rolled) steel pipe is not greater than 4% of the nominal wall thickness, and the maximum depth is not greater than 0.3mm.

E, both ends of the steel pipe should be cut into right angles, and remove burrs.

Stainless steel seamless pipe manufacturing process

1. Hot rolling (extruded seamless steel pipe) : round tube billet → heating → perforation → three-roll skew rolling, continuous rolling or extrusion → Stripping → sizing (or reducing) → cooling → straightening → hydraulic test (or detection) → marking → storage

The raw material of rolling seamless tube is round tube blank, and the round tube embryo is cut by the cutting machine and the billet with the growth degree of about 1 meter, and is sent to the furnace by conveyor belt for heating. The billets are heated in a furnace at a temperature of about 1200 degrees Celsius. The fuel is hydrogen or acetylene. The temperature control in the furnace is the key problem. After the round tube billet is released, it must be perforated by the pressure piercing machine. Generally, the most common piercing machine is the conical roll piercing machine, which has high production efficiency, good product quality, large perforating and expanding diameter, and can wear a variety of steel. After the perforation, the round tube blank is successively rolled by three roller skew, continuous rolling or extrusion. After extrusion, the tube should be removed for sizing. The sizing machine rotates into the steel embryo at high speed through the conical drill to punch holes and form the steel pipe. The inner diameter of the steel pipe is determined by the outer diameter length of the caliper drill bit. After the steel pipe is calibrated, it enters the cooling tower and is cooled by water spray. After the steel pipe is cooled, it will be straightened. After the steel pipe is straightened, it is sent to the metal inspection machine (or hydraulic test) for internal inspection. If there are cracks, bubbles and other problems inside the steel pipe, it will be detected. After the steel pipe inspection, it is also strictly selected by hand. After the steel pipe quality inspection, paint the number, specification, production batch number, etc. And hoisted by crane into the warehouse.

2. Cold-drawn (rolled) seamless steel pipe: round tube blank → heating → perforation → heading → annealing → pickling → oiling (copper plating) → multi-pass cold drawing (cold rolling) → billet → Heat treatment → straightening → hydraulic test (inspection) → marking → storage.

The rolling method of cold-drawn (rolled) seamless steel pipe is more complicated than that of hot-rolled (extruded) seamless steel pipe. The first three steps of their production process are basically the same. The difference starts from the fourth step, after the round tube blank is punched, it should be headed and annealed. After annealing, a special acidic liquid is used for pickling. After pickling, apply oil. This is followed by a special heat treatment of the tube after multiple cold drawing (cold rolling). After heat treatment, it is straightened.

Item	Stainless steel seamless/welded pipe
Standard	ASTMA312,A213,A376,A789,A790,A376,A249,EN10217-7-2005,GB14976-2002,GB13296-2009,JIS G3459-2004,JIS3463-2006
Material	201,304,310S,310,309,309S,316,316L,316Ti,317,317L,321,321H,347,347H,304,304L,301,302,201,202,etc
Surface	annealing,pickling,polishing,bright,sand blast,brush,hairline,etc
Machining	Custom, Kaiping, cutting, pattern
stainless steel round pipe/tube
Size	Wall thickness	1mm-150mm(SCH10-XXS)
	Outer diameter	6mm-2500mm (3/8"-100")
stainless steel square pipe/tube
Size	Wall thickness	1mm-150mm(SCH10-XXS)
	Outer diameter	4mm*4mm-800mm*800mm
stainless steel rectangular pipe/tube
Size	Wall thickness	1mm-150mm(SCH10-XXS)
	Outer diameter	6mm-2500mm (3/8"-100")
	Length	4000mm,5800mm,6000mm,12000mm,or as required.
Export to	Ireland,Singapore,Indonesia,Ukraine,Saudi Arabia,Spain,Canada,USA, Brazil,Thailand,Korea,Italy,India,Egypt,Oman,Malaysia,Kuwait,Canada, Viet Nam, Peru,Mexico,Dubai, Russia,etc
Package	Standard export seaworthy package,or as required.
Application	Widely used in petroleum,foodstuff,chemical industry,construction, electric power,nuclear,energy,machinery,biotechnology,paper making,shipbuilding,boiler fields. Pipes also can be made according to the customer's required.
Container size	20ft GP:5898mm(Length)x2352mm(Width)x2393mm(High) 24-26CBM 40ft GP:12032mm(Length)x2352mm(Width)x2393mm(High) 54CBM 40ft HC:12032mm(Length)x2352mm(Width)x2698mm(High) 68CBM

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