Fixed torque problem
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I’m seeking help from experts; this is my first time dealing with the issue of torque setting for bolts. 1. How is torque determined? 2. Given the flange specifications and dimensions as well as the medium pressure, is it also necessary to determine the type of gasket? For example: Compared to octagonal gaskets, metal wound gaskets have lower strength; are they prone to failure during torque application?
Take a look at the manufacturer’s data on torque.
I found the record of the set torque values from the last maintenance session; it contains formulas, and by entering the required values, the torque value is automatically calculated, after which it just needs to be rounded off. But according to those with more experience, the calculated values tend to be on the low side, probably due to idealization; as a result, the actual values obtained are higher, with some reaching more than twice that amount. I’m worried that this might damage the gaskets. From this perspective, the calculated torque value doesn’t hold much practical significance. I was thinking to use the calculated value as a minimum, then increase it by 10 percentage points each time, and add another 10 points once there is no leakage – is this approach feasible?
I remember some expert (it seems to be Sang Rubao) saying that there is a significant difference between the calculated value and the actual value. According to the 541 principle, after the torque exceeds a certain level, 90% of it is used to overcome friction; this actually has little impact on the clamping force. After reaching the rated torque, turning the bolt back by a quarter turn helps to reduce its torsional deformation.
You might want to follow the WeChat official account of Pressure Vessel Professionals; search for articles on bolt tightening knowledge – those articles are quite useful as a reference
541 is indeed a bit scary; how can we determine that the gasket is operating within the proper range?