EN GOST 9941 ultra thin wall stainless steel tube

GOST 9941-81 cold forming and hot forming corrosion resistant seamless steel pipe technical conditions

 

This standard is applicable to seamless stainless steel tubes with cold-formed and hot-formed corrosion resistant steel for general application

 

1.1 the outer diameter and wall thickness of stainless steel pipe shall be manufactured in accordance with the standard dimensions

 

1.2 stainless steel pipe shall be manufactured according to the following length: fixed length -- within the range of indefinite length, but not greater than the length specified in table 1, and the length limit deviation shall be +15mm;According to the agreement between the supplier and the supplier, it is allowed to produce steel pipe of greater than the fixed length specified in table 1.Multiple length -- within the range of fixed length, the residual amount of each segment is 5mm, and the ultimate deviation of the length is 15mm.The minimum ruler length is 300mm.Variable length -- when the wall thickness is less than 0.5mm, the length is from 0.75m to the length specified in table 1.Wall thickness of 0.5 mm?At 1.0mm, the length is from 1.0m to the length specified in table 1.When the wall thickness is 1.0mm and above, the length is 1.5m.12.5 m.According to the agreement between the supplier and the supplier, the production of steel pipe longer than 12.5m is allowed.According to the agreement of both parties, the diameter of steel pipe less than 25mm is less than 16m.

 

1.4 according to the requirements of the demander, the stainless steel pipe with limit deviation can be produced according to the combination of diameter and wall thickness.

 

1.5 according to the requirements of the demander, steel pipes can be made according to the inner diameter and wall thickness. The limit deviation of the inner diameter shall be agreed by both parties.

 

1.6 the ellipticity of steel tube shall not cause the limit deviation of steel tube diameter beyond the outer diameter of steel tube.

 

1.7 the bending degree of steel tube per meter in any section shall not exceed the following provisions;
When the diameter is greater than 5mm and the wall thickness is greater than 0.5mm --1mm/m;
> diameter 5mm, wall thickness < 0.5mm --2mm/m;

 

When the diameter is less than 15mm and the wall thickness is less than 0.5mm, the bending degree shall not be specified, but there shall be no obvious bending on such steel pipes.

 

1.8 the end of the stainless steel pipe shall be cut at right angles and the burrs shall be removed, allowing for chamfering and roughness of the end surface when the burrs are removed.According to the requirements of the demander, the steel pipe end with wall thickness greater than 5mm should have welded groove.Small amounts of rare earth metals are allowed to be added to make steel pipes.The sulfur content of welded steel pipe shall not be greater than 0.02%.Stainless steel pipe should be heat treated.Stainless steel pipe without heat treatment and non-bright surface can also be produced according to the requirements of the buyer.The mechanical properties and bending indexes of stainless steel tubes without heat treatment shall be agreed upon by both parties.

 

2.1 the stainless steel pipe shall be inspected on a batch basis.

 

Each batch consists of stainless steel tubes of the same diameter, wall thickness, steel number and heat treatment specification.According to buyer's requirements, each batch should also consist of the same furnace number of stainless steel pipe, according to provisions of GOST 10692-80 and fill in the same quality documents, and include: chemical components conform to the requirements of the quality of stainless steel tube blank documents, and information about the heat treatment, the number of each batch of stainless steel pipe should not exceed 300.

 

2.2 surface quality, size, hydraulic pressure and ultrasonic testing of steel pipes shall be conducted one by one.

 

2.3 the sampling quantity of each batch for quality inspection is as follows: stretching --2 stainless steel tubes;Flattening or expanding -1 stainless pipe;Intercrystalline corrosion -2 stainless pipes.According to the requirements of the buyer, corrosion tests were conducted on 10X17H13M2T, 08X17H15M3T,08X22H6T, 04X18H9, 08X18H10T, 12X18H10T, 08X18H10T, 08X18H2T, 12X18H9, 08x6x28mt.The yield limits of steel tubes no. 12X18H10T, 12X18H12T and 08X18H10T were measured.

 

2.4 even if only one indicator is unqualified, double number of stainless steel tubes should be taken from the same batch of steel tubes for re-inspection. The re-inspection results are applicable to the whole batch of stainless steel tubes.