Welding and allied processes
1Key Takeaways
This document applies to types of joint preparation for submerged arc welding with one wire electrode (process 121 according to ISO 4063) on steel. This document covers only the welding positions PA and PB according to ISO 6947. If PC is used, special preparation is necessary. This document applies to fully penetrated …
2Expert Interpretation
An in-depth interpretation of ISO 9692-2:2024, the international standard for submerged arc welding steel joint preparation, covering single-sided/double-sided butt joint types, groove size specifications, welding position requirements and process implementation points, which is applicable to submerged arc welding process design for steels thicker than 3mm.
Analysis of the core content of the standard
Scope of application
This standard applies to the preparation of steel joints by single-wire submerged arc welding (ISO 4063 process 121), mainly regulating full penetration welding in PA (flat welding) and PB (horizontal welding) positions. For materials with a thickness of >12mm, the standard recommends a composite groove design with a V-shaped or U-shaped root preparation.
Technical comparison of joint types
| Classification | Applicable thickness (mm) | Groove type | Key parameters | Special requirements |
|---|---|---|---|---|
| Single-sided welding (Table 1) | 3-12 | I-type butt welding | Gap ≤0.5t(max5mm) | Backing ≥5mm required |
| 10-20 | V-type groove | α=30-50°, gap 4-8mm | Root with ≤2mm blunt edge | |
| ≥30 | U-shaped groove | β=4-10°,R=5-10mm | Multi-layer and multi-pass welding is required | |
| Double-sided welding (Table 2) | 3-20 | Double I-shaped butt joint | Gap≤2mm | Gap needs to be strictly controlled |
| ≥16 | Double V-shaped groove | α=30-70°,c=4-10mm | Asymmetric design is allowed |
Technology Evolution and Implementation Points
Key points of standard update
- Compared with the 1998 version: the reference numbering system in Table 1/2 was adjusted to be consistent with the latest version of ISO 2553
- It was clarified that root weld can be completed by other fusion welding processes
- New steep groove types (1.17/1.18) are suitable for thick plate welding
Implementation recommendations
- Process verification: When formulating WPS according to ISO 15609-1, special attention should be paid to the tolerance control of root gap and blunt edge size
- Quality control: Referring to the ISO 3834 series of standards, clear requirements are put forward for interlayer slag cleaning of multi-layer welding
- Special working conditions: The groove parameters of the PC (vertical welding) position need to be designed separately. If necessary, the J-type groove can be used to reduce the amount of deposition
Application Case
In the manufacture of a pressure vessel, the standard recommended 2.6.6 double U-shaped groove is used for the 40mm thick Q345R steel plate:
- Groove angle: β=8°
- Root radius: R=8mm
- Blunt edge thickness: c=6mm
- Welding efficiency is increased by 30%, and deformation is controlled within 3mm