Stainless Steel Tubes

Stainless steel SS316/316L Tubes are made in order to meet the dimension standards of ASTM A213 / A269 made by ASTM International, which is formerly known as the American Society for Testing and Materials. The Stainless Steel Tubes are made in two different standards, TP316 and TP316L, hence the names SS316 / SS316L. The L stands for low carbon.

It comes from size 4mm to 60mm is available in 6 meters each length continuously marked along the length of the tube with outer diameter size, thickness, grade, standard, heat number and manufacturer name.

Outer Diameter Sizes	4mm to 60mm 1/4“OD to 2”OD
Material Specifications	TP316 / SS316 TP316L / SS316L
Dimension Specification	ASTM A269/A213
Finishing	Annealed and Pickled (AP) Polished 320 Grit Bright Annealed

Stainless Steel Tubes Catalogue

Stainless Steel Tubes
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What are Stainless Steel Tubes

1. What is stainless steel tube used for?

The SS316/316L tubes are the best for medium to long term usage. This includes projects, and/or equipment. Being offered in multiple different appearances, it is suitable for use in indoor, or outdoor projects, where the tubes can be made to be as aesthetically pleasing as possible, or be made simply to serve its purpose.

The SS316/316L tubes are also made with multiple different finishes, in accordance with what is appropriate for the project or equipment where it will be used. It can either be made to suit a project where the tubes need to be manually reshaped for its purpose, or it can be made to suit a project where the tubes need to look as polished and clean as possible at all times. The tube material also guarantees longevity whilst also ductility as well as hardness. These tubes are considered as the industry standard for Refinery and Offshore Oil and Gas projects.

SS316/316L Dual Specifications

2. What stainless steel tube is made of?

Maximum carbon content for SS316 tube is 0.08%, while 0.03% for SS316L. This means that the low carbon tube becomes more ductile when annealed, as well as being more resistant to corrosion, especially after welding. The only thing to consider when choosing between the two is mostly about welding. If the tubing is going to be welded during the fabrication process, highly consider using the SS316L version. Carbon content would have to be at a level of 0.03% maximum in order to be dual spec certified as SS316/316L grade.

3. What are the stainless steel tube grades?

There are 3 types of finishing available: Annealed and Pickled (AP) seamless tube which is matt surface, polished 320 grit and bright annealed, which is a shiny surface. AP tubes are commonly used throughout industry projects where appearance finishing is not critical. Annealed finishing reduces the hardness of the material, making it more workable using a heating process that increases ductility. This means that it will be easier to bend and manipulate rather than the pickled version. The pickled version offers a purer look, where impurities such as contaminants, stains and rust are removed. Polished or BA tubes are used for OEM’s who manufacture panels and analysers houses, where aesthetic appearance is important and part of the project consideration.

Stainless Steel Tube Marking

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4. Stainless steel tube tolerance chart

SS316 Tube 6 meters long

The SS316 and SS316L tubes are both of MO2.0 and MO2.5 standards. Tubes with MO2.5 follow the minimum 2.5% Molybdenum content which enhances the tube’s resistance to corrosion. Compared to standard MO2.0 tubes, MO2.5 tubes are used in applications that are more corrosive, such as petrochemical, oil and gas and marine industry.

As stainless steel tubes made according to ASTM A213/A269 standard, there is a specific tolerance that needs to be fulfilled in order to install properly with compression end fittings.

Tube Outer Diameter	Tolerance
4mm to 35mm	+/- 0.08mm
35mm to 38mm	+/- 0.15mm
38mm to 60mm	+/- 0.20mm
60mm and above	+/- 0.25mm

A269 and A213 have two different types of wall thickness tolerance. The permissible variations in wall thickness calculation is +/− 10% for ASTM A269. However, according to ASTM A213, there are two options to follow for wall thickness tolerance as per below:

ASTM A213	Maximum Wall Thickness	Minimum Wall Thickness
Minimum Wall Thickness (MWT)	20%	0%
Average Wall Thickness (AWT)	10%	10%

Our standard option for wall thickness is +/- 10%, which comply with both ASTM A269/213 standards. Due to cost saving, the common practice and ready stock in the market is average wall thickness. Minimum wall thickness is available upon request and there is a minimum order quantity required.

5. How do you bend stainless steel tubing?

A maximum bend radius of 3x the external tube diameter is recommended for the SS316 and SS316L tubes for cold bending of the tubes, or bending by hands. These tubes are very suitable for arc welding as well, and can easily be done using the proper equipment and technique.

These tubes are very easily installed, and can be either fit to single or double ferrule fittings, or welded together. Its high ductility means that it is easily manipulated and can be placed in many different positions and orientations as needed, as long as they are attached properly. They can also be combined with clamps in order to keep from too much vibration if there is a higher amount of pressure coming from within the tubes.

Tube and ferrule hardness forms a correct and successful compression joint-in and ensures ferrules are able to swage onto the tube. The critical part is the tube surface which is used as a sealing mechanism. Any scratches or damage to the tube surface could affect the installation and thus tubing in poor performance.