Do the welds of fatigue-resistant containers have to be ground to be level with the base metal?
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Do the welds of fatigue-resistant containers have to be ground to be level with the base metal? However, the equipment is still designed for 150 pressure, with only alternating pressure; the manufacturing requirements remain those for fatigue-resistant containers. There isn’t much contact with fatigue-prone containers – are there any other special aspects?
It’s better to grind the main weld flat as well
Fatigue-prone vessels should be designed, manufactured, and inspected in accordance with JB4732. However, there are some vessels where, although the loads vary, the operating conditions are not severe; examples include air tanks used in dust collectors and air cannons utilized in blockage-clearing equipment. All Class A and Class B welded joints of pressure vessels should be ground smooth to prevent stress concentration under load. For containers with strict requirements, embedded type fittings should be used to prevent stress concentration at the corners when the fillet welds are under load, which could lead to failure of the welds and the base material.
The equipment can be designed in accordance with GB/T150 only if the design pressure is greater than 5 times the alternating stress intensity amplitude, or if the number of pressure cycles during the equipment’s design life is less than 1000. Pressure alternating equipment designed in accordance with GB/T150 does not require the welds to be smoothed.
Regardless of the type of equipment, grinding the welds smooth is a standard practice in manufacturing.
In China, except for those with special requirements, polishing is generally not done.
It’s mentioned on jb4732, in the last sections discussing the excess height of welds. Furthermore, when it comes to fatigue-resistant containers, it’s not just the number of 1000 cycles that matters; there are also limitations related to the material, right?
The fatigue-resistant joint areas are ground to be level with the main weld seam, while the R corners of the fillet welds are smoothly transitioned