Stainless Steel Pipe

Stainless Steel Tubes

GNEE provides steel pipe Size:
(Seamless Stainless Tubes)
Outside Diameter: 6.35mm to 813mm, Wall Thickness: 1mm to 55mm
(Welded Stainless Tubes)
Outside Diameter: 10mm to 2500mm, Wall Thickness: 1mm to 30mm
Standard: ASTM A213, ASTM A269, ASTM A312, ASTM A789, ASTM A790, ASTM A249, ASTM B444, JIS G3463, JIS G3459, DIN17456, EN10217-7
Grade: TP304, TP304L, TP316L, S31254, S31803, S32205, S32750, Inconel625, TP410, TP430
Application: Used for Heat Exchanger, Condenser, Boiler, The Food Hygiene Grade Tubes, Stainless Steel Tubes for Mechanical Structure / Building Decoration, Seawater Desalination and Water Treatment Piping.
 

Standard Comparison
Stainless steel tube & pipe wall thickness tolerance are the same as the general accuracy of American ASTM / ASME and EU standards, but slightly lower than the high requirements of the EU standards.
Stainless steel tube & pipe outer diameter tolerances are mostly lower than American standards, and approaching the EU standards. it is more reasonable that the American standard specify the OD tolerance is tight, compared to thickness tolerance.
China GB standards and EU standard have no weight tolerance specified, seamless tube & pipe in GB standard delivery goods as actual weight or theoretical weight, welded tube & pipe as theoretical weight or actual weight.

Out Of Roundness
Out of roundness, sometimes referred to as ovality is tube or pipe on the same cross-section of the outer diameter, roundness or ovality is difference between the maximum and minimum dimensions of outside diameter, is carefully measured the high and low points at any one section of the tube or pipe.

 Eccentricity
Concentricity or eccentricity refers to tube & pipe wall thickness variations, if need a high precision in tube tolerance, or fit into other tube or parts, which need a good concentricity.

 Concentricity be contained wall thickness tolerance specified in EU standard, and just specified in ASTM A1016/M OD≥50 mm and t≥5.6 mm thick wall stainless steel tube the same cross section thickness varieties.

For seamless tube,

WTmax – WTmin ≤ ±10% (WTmax + WTmin) / 2

For welded tube,

WTmax – WTmin ≤ 5% (WTmax + WTmin) / 2

Straightness
Standard pipes and tubes are supplied straightened to the eye: for special applications the permissible deviation from the straight line may be agreed between purchaser and tube manufacturer; the maximum permissible deviation from the straight line related to the length of measurement L is to be indicated, e.g. 1mm/1000mm.

Stainless steel pipe production process:
Raw materials--slitting--welding pipe making--end trimming--polishing--inspection (printing)--packaging--shipping (warehousing) (decorative welded pipe).
Raw materials - slitting - welding pipe making - heat treatment - correction - straightening - trimming - pickling - hydraulic test - inspection (printing) - packaging - shipping (warehousing) (Welded pipe for industrial piping).

Stainless steel pipe connection method

There are various connection methods for stainless steel pipes. Common pipe fitting types include compression type, compression type, union type, push type, push thread type, socket welding type, union flange connection, welding type and welding and traditional connection. Combined derived series connection methods. These connection methods have different application scopes according to their different principles, but most of them are easy to install, strong and reliable. The sealing ring or gasket material used for the connection is mostly made of silicone rubber, nitrile rubber and EPDM rubber that meet national standards, which relieves users from worries.
Pressure connection steps
1. Pipe breaking: Cut the pipe to the required length. When breaking the pipe, do not use excessive force to prevent the pipe from losing its roundness.
2. Remove burrs: After cutting the pipe, the burrs should be removed to avoid cutting the sealing ring.
3. Line marking: In order to completely insert the steel pipe into the pipe fitting socket, the insertion length must be marked and drawn on the pipe end.
4. Assembly: The sealing ring should be correctly installed in the U-shaped groove of the pipe fitting, insert the pipe into the socket of the pipe fitting, and wait for crimping.
5. Crimping: During crimping, the convex part of the pipe fitting is placed in the concave groove of the mold, and the jaws are kept perpendicular to the axis of the pipe.
6. Inspection: After the crimping is completed, use a special gauge to check the crimping size.

Hardness
Stainless steel pipes generally use three hardness indicators: Brinell, Rockwell, and Vickers to measure their hardness.
Brinell hardness
Among stainless steel pipe standards, Brinell hardness is the most widely used. The indentation diameter is often used to express the hardness of the material, which is both intuitive and convenient. But it is not suitable for steel pipes made of harder or thinner steel.
Rockwell hardness
The Rockwell hardness test of stainless steel pipe is the same as the Brinell hardness test, which is an indentation test method. The difference is that it measures the depth of the indentation. Rockwell hardness test is currently a widely used method, among which HRC is used in steel pipe standards second only to Brinell hardness HB. Rockwell hardness can be used to measure metal materials from extremely soft to extremely hard. It makes up for the shortcomings of the Brinell method. It is simpler than the Brinell method and the hardness value can be read directly from the dial of the hardness machine. However, due to its small indentation, the hardness value is not as accurate as the Brinell method.
Vickers hardness
The Vickers hardness test of stainless steel pipe is also an indentation test method that can be used to determine the hardness of very thin metal materials and surface layers. It has the main advantages of Brinell and Rockwell methods and overcomes their basic shortcomings, but it is not as simple as Rockwell method. Vickers method is rarely used in steel pipe standards.
Hardness testing
For annealed stainless steel pipes with an inner diameter of more than 6.0 mm and a wall thickness of less than 13 mm, the W-B75 Webster hardness tester can be used. The test is very fast and simple, and is suitable for rapid and non-destructive qualification inspection of stainless steel pipes. For stainless steel pipes with an inner diameter greater than 30mm and a wall thickness greater than 1.2mm, use a Rockwell hardness tester to test HRB and HRC hardness. For stainless steel pipes with an inner diameter greater than 30mm and a wall thickness less than 1.2mm, use a surface Rockwell hardness tester to test the HRT or HRN hardness. For stainless steel pipes with an inner diameter less than 0mm and greater than 4.8mm, use a special Rockwell hardness tester for pipes to test the HR15T hardness. When the inner diameter of the stainless steel pipe is greater than 26mm, the hardness of the inner wall of the pipe can also be tested with a Rockwell or surface Rockwell hardness tester.

ALLOY STEEL PIPEINSPECTION

Chemical composition inspection, mechanical properties test (tensile strength, yield strength, elongation, flaring, flattening, bending, hardness, impact test), surface and dimension test, no-destructive test, hydrostatic test.

APPLICATION AREAS

Auto industry
Stainless steel is mainly used in the exhaust system, accounting for more than 1/2 of the total stainless steel consumption in automobiles, and 80% is ferritic stainless steel. The exhaust gas produced by the automobile engine passes through the exhaust air intake pipe, front pipe, hose, converter, center pipe and finally flows out of the muffler. Commonly used steel types for exhaust systems include 409L, 436L, etc. Car mufflers mainly use stainless steel welded pipes.
Petrochemical industry including fertilizer industry
The demand for stainless steel pipes is huge. The industry mainly uses stainless steel seamless pipes. The specifications include: 304, 321, 316, 316L, 347, 317L, etc., with an outer diameter of around ￠18-￠610 and a wall thickness of 6mm-50mm. Left and right (usually medium and low-pressure transportation pipes with specifications above Φ159mm are selected). The specific application areas are: furnace pipes, material transportation pipes, heat exchanger pipes, etc.
Fluid transportation such as water and gas
Stainless steel pipes and their water delivery equipment are the most advanced basic water purification materials in the world today. Their anti-corrosion properties are unmatched by cast iron pipes, carbon steel pipes, plastic pipes, etc. The best material for the water industry such as water preparation, storage, transportation, purification, regeneration, and desalination.

 

 

 

 

DELIVERY

Steel pipe delivery status(condition)

Steel pipe delivery status(condition): cold / hard (BK), cold / soft (BKW), after cold stress relief annealing (BKS), annealing (GBK), normalized (NBK).

Condition on delivery of steel pipe

GNEE PACKAGING AND SHIPPING

Bare packed/bundled packed/crate packed/tubes with wooden protection on both sides and suitably protected for sea shipping or as per requirement.

Add plastic caps to both sides of the pipe end
Damage caused by strapping and transportation should be avoided
Bundling signs should be uniform and consistent
Steel pipes in the same bundle (batch) should come from the same furnace.
The steel pipes have the same furnace number, the same steel grade, and the same specifications.

 

 

 

 

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