The 8" pipe cap has body cracks near the girth weld.
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As shown in the picture, there is a crack on the outer surface near the girth weld. The crack is parallel to the weld. After cutting, there is no problem inside. What is the reason for this?
What is this? Is this a slot?
Look at your pictures. There are several questions: The root of this pipe and pipe cap is not welded through? Does the defect appear on one side of the pipe cap, extending vertically from the edge of the weld to the pipe cap? What is that white strip on the inside of the vertical weld?
This post was last edited by Xiao Pad on 2020-5-31 18:29 1. It should be that there is no argon arc primer, and the bevel is directly welded. 2. The defect is the annular part of the pipe cap, which has a large number of annular surface cracks parallel to the weld. 3. The white strip is a cut made with an angle grinder to confirm whether there is an internal problem. There are several crack analyzes at this location on the Internet, but they are all penetrating cracks perpendicular to the welding joint. Mine is a surface crack parallel to the welding joint, which is about 30c by visual inspection.
Recheck the material of the pipe cap. By the way, you can check the welding process evaluation and actual welding conditions...it may be that the material of the pipe cap is wrong, or it is not up to standard.
For single-sided welding, there may also be problems such as the welding temperature being too high. It is basically a problem of welding and materials.
From the appearance, it doesn't look like cracks, but looks like wrinkles formed during the hot pressing process. It should be done with surface penetration first, and it will be useless after cutting it.
It is obvious to the naked eye that it is cracking from the inside. Even if it is wrinkled, have you ever seen a manufacturer deliver wrinkled products to users? Do you dare to use them? If something goes wrong, will you just keep using it if you don't deal with it?
I feel like this has something to do with the processing material of the cap. Is there any impurity in the blank? ?