TA2 bends backward after welding, and breaks due to back bending
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After butt welding of TA2 plates with a thickness of 8, a weld evaluation was conducted; 100% of the RT tests passed, the tensile tests were successful, but the bending tests failed as the plates broke completely. Who has relevant experience?
It is already very difficult for TA2 sheets to pass bending tests, and titanium materials are rarely bent or cold-formed; therefore, conducting bending tests on welded joints is extremely challenging
This post was last edited by wanlirn on 2022-1-26 at 16:03. TA2 material should not be sourced from small manufacturers; although its chemical composition may be acceptable, there are two issues: either the oxygen content is too high, or the quality of the annealing process is poor. The oxygen content cannot be determined using a spectrometer either； The standards only specify a lower limit for tensile strength; as a result, small manufacturers generally end up with materials that have too high a strength, meaning they are too hard ； We use plates designed specifically for export when conducting weld evaluations ； Baotai or Western Materials’ products will work; if that’s not possible, use TA1 plates, and have them provide a material specification for TA2 ； There is a huge difference in the quality of titanium products produced domestically. Also, using commercial-grade welding wire can lead to problems; the plates you purchase have issues – they are too strong – and when combined with high-quality welding wire, the welds turn out to be soft, making it impossible to bend them. Try using wire cut from the base material; it’s not allowed per the standards, but there’s nothing that can be done about it. . .
Titanium 2 has relatively good ductility; I used 25*1.5 titanium 2 welded tubes to bend elbows with a R60 radius, and there were no issues at all. The Titanium 10 made last year was also 25*1.5, R60; this one is more complicated due to the inner lining core in the tube. It seems there might be an issue with the material of your pipes; I recommend conducting a spectroscopy test.
A different welder was used, and the bending process was repeated; 6 pieces were made, of which 4 passed the inspection, so it can be considered successful. The material of the sheet itself only bends by 105 degrees; then why is 180 degrees specified as the acceptable value in standard 47014? Those who set the standards are being too careless. The base material itself cannot achieve a 180-degree bend to meet the requirements, which makes it rather difficult to obtain satisfactory weld evaluation results.
Where did your family buy the TA10 pipes? They are welded pipes, right? Seamless ones still can’t be produced by any manufacturer yet