A small question regarding socket welding
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I would like to ask everyone: recently I noticed that the standards for flanges include illustrations showing that when welding steel pipes using the socket weld method, the top of the pipe penetrates into the flange groove, leaving a distance of 2 mm between it and the bottom of the groove. Why is there such a distance? Is it a strict requirement?
This distance from the mother piece is intended to prevent deformation and cracking that can occur due to expansion during welding followed by contraction.
Is it the expansion distance given to the pipe? So, does this distance change when welding different types of pipes?
This post was last edited by caozuogong on 2011-5-19 08:19. The standards specify this; mainly, during welding the pipe fittings are at high temperatures, and after cooling they contract, which can lead to cracking or excessive stress concentration. Generally, we just need to insert the tube all the way in and then lift it up a little. No one actually measures the gap value.
GB 50235-2010 Clause 6.0.7 2； Prevent contraction after expansion during welding, which could lead to deformation and cracking.
The project I’m working on now requires RT testing for this gap, and it should be carried out absolutely.
Reply to 6# 494067920: Are there any specific numerical testing standards?
Reply 7# bronghua: For the joint fitting of socket welds, a 2 mm thick paper disc or specially designed expansion rings (such as Gap-a-Let rings) can be used at the bottom of the joint to ensure a gap of at least 1.0 mm after welding. The maximum allowable gap after welding should be 3.0 mm. For the assembly of socket weld joints, a 2 mm thick piece of paper or specially designed expansion rings (like Gap-a-Let rings) should be used at the bottom of the joint to maintain a gap of 1.0 mm after welding. The maximum gap after welding is 3.0 mm.
Reply to 8# 494067920: I understand, thank you very much! :handshake