What is ISO/TR 20172 about?
ISO/TR 20172 establishes a European grouping system for materials for welding purposes. This system is classified in accordance with the grouping system of ISO/TR 15608. It is also applicable for other purposes such as heat treatment, forming and non-destructive testing.
ISO/TR 20172 covers grouping systems for the following standardized materials:
- Steel
- Aluminium and its alloys
- Copper and its alloys
- Cast irons
- Nickel and nickel alloys
Note: For materials that are not assigned to a group in ISO/TR 20172, the criteria of ISO/TR 15608 apply.
Who is ISO/TR 20172 for?
ISO/TR 20172 on welding applies to:
- Construction, automotive, mechanical Industries
- Sheet metal manufacturers
- Manufacturers of pressure vessels
- Manufacturers of aircraft & aerospace
- Shipbuilding industry
- Welding equipment manufacturers
Why should you use ISO/TR 20172?
It is important to classify and group materials for welding purposes. The use of material classification and grouping for welding purposes in accordance with ISO/TR 20172 improves the quality and efficiency of welding operations used in manufacturing and heat treatment processes.
ISO/TR 20172 helps design engineers to design cost-effective products by choosing appropriate standard classified material according to market demand and best industry practice ISO/TR 20172 aids design engineers to communicate design requirements for a particular manufacturing process and product.
With a better classification of materials, you will be able to determine the chemical composition and mechanical qualities of the material, ISO/TR 20172 allows you to manufacture the high- quality products.
What’s changed since the last update?
PD CEN ISO/TR 20172:2021 supersedes PD CEN ISO/TR 20172:2009, which is withdrawn.
The technical changes compared to the previous edition are as follows:
- Tables 1 to 5 have been revised
- New Table 6 has been added for nickel and nickel alloys

