P235TR1

- P235TR1 the capital letter P for pressure purposes;
- P235TR1 is the required minimum yield strength for thicknesses less than or equal to 16mm;
- TR1 is the alphanumeric code for qualities without defined aluminum content, impact characteristics, or special inspection and testing criteria.

- Tube Surface

These tubes must be free from external and internal surface defects that can be detected by visual examination. It is permissible to dress surface imperfections by grinding or machining provided that the wall thickness in the dressed area is not less than the specified minimum wall thickness. All dressed areas must blend smoothly into the contour of the tube. Any surface imperfection that is demonstrated to be deeper than 5% of the wall thickness T or 3mm, whichever is smaller, must be dressed. 

Tubes shall be marked at least at one end, in order to facilitate their identification during transport, storage and use. The manufacturer’s name or trade mark and the product brand shall be indelibly marked on the tube by a suitable method. If the tube’s outside diameter is over 51mm, the manufacturer may replace this information with a label or tag, which shall be securely attached to the bundle or box. This label or tag shall identify the tube diameter, wall thickness and length range. In addition, the type of tube (EW, HFW, SAWL or SAWH – Symbol in accordance with the standard) and the standard number (EN 10217-1) shall be marked on the tube. For tubes made of carbon steel, the steel name or steel number shall also be included in the marking. This information helps to ensure that tubes are used in accordance with their intended purpose and are not mixed up with other types of tubes. Automated link or paint marking processes, paint stencils or hard stamps (using low stress or pin stamps) are all suitable methods for marking tubes.