What causes longitudinal cracks in pipe fittings?
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There is an ammonia synthesis tower; the material (with an exit temperature of 429°C and a pressure of 12.6 MPa, in pipes with a diameter of φ219 and made of 1Cr18Ni9Ti material) flows from the synthesis tower into a cooler where water vapor is generated. The cooler has a cross-piece with a diameter of φ168, made of 12CrMo material, and this cross-piece is equipped with a control valve (the material before the valve is 1Cr18Ni9Ti)； Material behind the valve: 12CrMo), opening degree 20–40%. The material exits the cooler and merges with the crossline; the temperature after merging is 280°C. The problem is that longitudinal cracks have appeared in the tees at the intersections across lines, as well as in the line-crossing elbows, along with cracks in the welds. Please ask the marine enthusiasts in this forum to analyze what might be causing such damage
Give it a push, don’t let it sink; wait for someone who knows how to help to take a look.
Let’s draw a diagram and take a look first.
There is one diagram; I originally wanted to do the calculations, but the necessary conditions are missing. Can’t we analyze it based on experience first?