Selection of device flange studs
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JB/T4707-2000 standard equipment flange studs are commonly used; the standard defines two types, A and B – I’m not sure how to choose between them
For Type A studs, the diameter d2 of the unthreaded portion is equal to the pitch diameter of the thread; for Type B studs, d2 is equal to the root diameter d1, and a circular arc of radius r must be used to connect d1 and d2. Type B is difficult to process, while Type A is easy to process
As far as I can tell, in practical use of equipment flange studs according to JB/T4707-2000, type A is used more frequently.
Type B is mainly used in applications with high loads, large pressure fluctuations, and significant temperature differences, as it can withstand stresses better than Type A
Type A studs are suitable only for applications with moderate temperatures and pressures, while Type B studs are suitable for applications with higher pressures and temperatures.
Take a look here: http://bbs.hcbbs.com/viewthread.php?tid=352860&highlight=%C2%DD%D6%F9
Type A studs are suitable only for applications with modest requirements, while Type B studs are appropriate for situations with high pressure and temperature or unstable operating conditions.
Try to choose type B. Since the B-type fine-shaft structure is connected to the thread through a small radius transition, the overall structural continuity is better, which reduces stress concentration; as a result, compared to A-type studs, it has a greater capacity to withstand alternating loads, that is, it exhibits better fatigue resistance.