ASTM stainless steel seamless pipes/tubes
The stainless steel seamless pipe is round, and the stainless steel seamless tube can be round, square, rectangular, oval, hexagonal, etc.
Stainless steel seamless pipe/tube is long steel with a hollow cross-section and no peripheral joints. The thicker the wall thickness of the product, the more economical and practical it is, while the thinner the wall thickness, the higher the processing cost.
The process of the product determines its limited performance, the general seamless steel tube/pipe precision is low: uneven wall thickness, low brightness of the tube appearance, high cost of sizing, and the internal and external appearance of the pockmarks, black spots are not easy to remove; it is a whole made, no welding seams, so it reflects its superiority in high pressure, high strength, mechanical structure materials.
4~8m
3-40mm
According to the rolling method, there are hot rolled, hot extruded, and cold drawn (rolled) stainless steel tubes/pipes.
According to different material types of stainless steel, there are semi-ferritic and semi-martensitic stainless steel seamless tubes/pipes, martensitic stainless steel seamless tubes/pipes, austenitic stainless steel seamless tubes/pipes, austenitic-ferritic stainless steel seamless tubes/pipes, etc.
According to the shape of the section can be divided into round pipes and tubes, Pipe is round, the tube can round, square, rectangular, semi-circular, hexagonal, equilateral triangle, octagonal, and other shaped stainless steel tubes.
A, The usual length of steel pipe (indefinite) hot-rolled steel pipe/tube 1.5 ~ 10m, hot extruded steel pipe/tube equal to and greater than 1m. cold-drawn (rolled) steel pipe/tube wall thickness 0.5 ~ 1.0mm, 1.0 ~ 7m; wall thickness greater than 1.0mm, 1.5 ~ 8m.
B, hot-rolled (hot extrusion) steel pipe/tube diameter 54 ~ 480mm a total of 45 kinds; wall thickness 4.5 ~ 45mm a total of 36 kinds. Cold-drawn (rolled) steel pipe/tube diameter 6 ~ 200mm a total of 65 kinds; wall thickness of 0.5 ~ 21mm a total of 39 kinds.
C, the inner and outer surface of the steel pipe/tube shall not have cracks, folding, cracking, crazing, rolling folding, delamination, and scarring defects exist, these defects should be completely removed (except for mechanical processing of the tube/pipe) after removal shall not make the wall thickness and outside diameter exceed the negative deviation. Where other minor surface defects do not exceed the allowable negative deviation may not be cleared.
D, straight channel allowable depth. Hot-rolled, hot extruded steel pipe/tube, diameter less than and equal to 140mm is not greater than 5% of the nominal wall thickness, the maximum depth is not greater than 0.5mm; cold-drawn (rolled) steel pipe/tube is not greater than 4% of the nominal wall thickness, the maximum depth is not greater than 0.3mm.
E. Both ends of the steel pipe/tube should be cut at right angles and cleared of burrs.
According to the different production methods can be divided into hot-rolled tubes, cold-rolled tubes, cold-drawn tubes, extruded tubes, etc.
1. Hot-rolled (extruded seamless steel pipe/tube): round billet → heating → perforation → three-roll slant rolling, continuous rolling or extrusion → detubing → sizing (or reducing) → cooling → straightening → hydrostatic test (or flaw detection) → marking → storage
The raw material for rolling seamless pipes is a round pipe billet. The round pipe embryo is cut and processed into a billet of about 1 meter in length by a cutting machine and sent to the furnace for heating via a conveyor belt. The billet is heated in the furnace at a temperature of approximately 1200 degrees Celsius. The fuel is hydrogen or acetylene.
Temperature control in the furnace is a key issue. After the round billet is discharged from the furnace, it is hollowed out by a pressure-piercing machine. The more common perforating machine is the conical roller perforating machine, which has high productivity, good product quality, large perforation, and expansion capacity, and can perforate a variety of steel grades.
After perforation, the round pipe billet has been three rolls of oblique rolling, continuous rolling, or extrusion. After extrusion, the tube should be sized.
Sizing machine through the conical drill bit high-speed rotation into the steel embryo perforation, the formation of steel pipe/tube. The inner diameter of the steel pipe/tube is determined by the length of the outer diameter of the sizing machine bit.
After sizing, the steel pipe/tube enters the cooling tower and is cooled by water spray, and after cooling, the steel pipe/tube is straightened. Steel pipe/tube is straightened and sent by conveyor belt to the metal flaw detector (or hydraulic test) for internal flaw detection.
If there are cracks, bubbles, and other problems inside the steel pipe, they will be detected. The steel pipe/tube quality inspection is followed by a strict hand selection. After quality inspection, the steel pipe is sprayed with paint with a number, specification, production lot number, etc. And lifted into the warehouse by crane.
2. Cold-drawn (rolled) seamless steel pipe: round billet → heating → piercing → beating → annealing → pickling → oiling (copper plating) → multi-pass cold-drawing (cold rolling) → billet → heat treatment → straightening → hydraulic test (flaw detection) → marking → storage.
The rolling method of cold-drawn (rolled) seamless steel pipe/tube is more complex than that of hot-rolled (extruded seamless steel pipe/tube). The first three steps of their production process are basically the same. The difference starts from the fourth step, after the round pipe billet is hollowed out, it has to be tapped and annealed. After annealing, it is pickled with a special acidic liquid. After pickling, oil is applied. Then it is immediately followed by multiple passes of cold drawing (cold rolling) and then billet pipe, a specialized heat treatment. After heat treatment, it has to be straightened.
1.1, hot-rolled stainless steel seamless tubes/pipes are generally produced on the automatic tube/pipe rolling units. Solid billets are inspected and cleared of surface defects, cut to the required length, centered on the perforated end of the billet, then sent to the heating furnace for heating and perforated on the perforating machine.
In the perforation, while continuously rotating and advancing, under the action of the rollers and top head, the internal cavity of the billet gradually formed, called the hairpin. Then sent to the automatic tube rolling machine to continue rolling. Finally, the wall thickness is equalized by the equalizing machine, and the diameter is fixed by the sizing machine to meet the specifications. The use of a continuous rolling mill to produce hot rolled seamless steel pipe is a more advanced method.
1.2, if you want to get a smaller size and better quality seamless pipe, you must use the cold rolling, cold drawing, or both combined methods. Cold rolling is usually carried out on a two-roller mill, steel pipe in a circular hole pattern consisting of a circular groove with a variable section and an immobile conical head. Cold drawing is usually carried out on a single-chain or double-chain cold drawing machine of 0.5 to 100T.
1.3, the extrusion method is about heated billet placed in a closed extrusion cylinder, perforated bar, and extrusion rod together with the movement of the extrusion, so that the extruded parts from the smaller die hole. This method can produce smaller diameter steel pipes.
For steel tubes/pipes subjected to fluid pressure are pressure does not occur leakage, wetting or expansion for qualified, some steel tubes also according to the standard or demand-side requirements for rolled edge test, flaring test, flattening test.
201
202
301
302
SUS304, SS304, TP304
SUS304L、SS304L、TP304L
SUS321、SS321、TP321
SUS316、SS316、TP316
SUS316L、SS316L、TP316L
SUS310S、SS310S、TP310S
Stainless Steel tube/pipe standard
W = Circumference×wall thickness(m) × Pm(density of tube matertail kg/m3 )×length×1000= KG/M
Round tube/pipe weight
Circumference = π(314)× outer diameter
W = π(314)×outer diamemter(m)×wall thickness(m) × Pm(density of tube mertail kg/m3 )×1000= KG/M (weight per meter).
SS304 Pm is 7.93, SS316 Pm is 7.96
Example
Diameter38.1, wall 2.5mm, length 1m, 304material
W=3.14×0.0381×0.0025×7.93×1×1000=2.37KGS
Square tube weight
Circumference = size×4
W = Size(m)×4×wall thickness(m) × Pm(density of tube mertail kg/m3 )×1000= KG/M (weight per meter).
SS304 Pm is 7.93, SS316 Pm is 7.96
Example
Square 40×40mm tube, wall 2.5mm, length 1m, 304material
W=0.04×4×0.0025×7.93×1×1000=3.172KGS
Rectangular tube weight
Circumference = （W+L）× 2
W = （W+L）× 2 ×wall thickness(m) × Pm(density of tube martial kg/m3 )×1000= KG/M (weight per meter).
SS304 Pm is 7.93, SS316 Pm is 7.96
Example
Rectangular 25×50mm, wall 2.5mm, length 1m, 304material
W=(25+50)×2×0.0025×7.93×1×1000=2.97KGS
Applications used by these industries include:
ASTM Stainless steel seamless pipes/tube prices $500-5000/ton