Cracking in welds of pipe elbows and tees
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Cracking occurred in the middle of the welds on the circulating water pipeline; the components involved were carbon steel elbows and tees. The issue was detected two hours after the water started flowing. Argon arc welding was used for the welding, with stainless steel welding wire. What could be the reasons for this? 1. Is it not appropriate to use stainless steel welding wire for argon arc welding? 2. Is it because the material of the carbon steel elbow contains impurities? 3. Since the crack is located in the middle, could it be caused by stress?
Carbon steel material – why use stainless steel welding wire? Has the welding assessment been done?
Normally, carbon steel comes with its own welding wire; using stainless steel welding wire is considered a more advanced approach. As long as the welding process is proper, there should be no problems. Regarding your situation, I have 3 questions: 1. Has the weld been X-rayed, and is its quality satisfactory? 2. Has stress calculation been done on the pipeline? 3. Has water hammer occurred?
In theory, stainless steel welding wire can be used for carbon steel. I guess: the welder who did it can’t weld
This post was last edited by Jiangtai Ren on 2017-4-15 at 17:20. Additional note: After using stainless steel welding wire with TIG welding for the base layer, another layer is also created using stainless steel welding wire with TIG welding. The water pressure is not high, at only 5 kilograms, so no imaging tests were conducted, nor was any stress analysis performed. It has been confirmed that there is no water hammer, and the pipeline vibration is minimal. Please analyze the reasons for the cracks that appear in the middle of the welds as shown in the photos, and suggest ways to address these issues.
It could be a problem with the welding rod, or it might be the welder’s skill – the welding machine wasn’t adjusted properly during welding.
Vibration, stress problems, stress analysis of construction pipelines
It does not belong to the higher-generation category; rather, it is two different alloy series