What is the proper torque for CF Flange bolts? A common practice to tighten CF flanges involves tightening the bolts until a “metal to metal” connection is made. This practice usually ensures that the gasket melds properly into the flanges and creates the necessary leak-tight seal. When using this method, take caution not to over-tighten or damage the bolts.

Another way to tighten bolts is to apply a specified torque. The general rule is to tighten bolts to 75% of the material yield stress. This prevents bolt damage and compresses the gasket to create the leak-tight seal.