Stainless steel flange stud tip section creep variable

　　With neck butt welding of stainless steel flange connection within the flange surface temperature of 573 k load. Stainless steel flange and stainless steel pipe outside surface without applying thermal insulation layer, considering the air layer between the flange and bolt hole air layer, fluctuation on the surface of the stainless steel flange surface heat transfer effect the temperature distribution of the system. External surface of the stainless steel flange, bolt and nut and air contact parts, applying equivalent convective heat transfer coefficient, air layer and the upper and lower flange bolt hole air layer between the exert their equivalent coefficient of thermal conductivity.

　　Along the gasket by radial temperature gradually reduce outside introversion, temperature difference between inside and outside about 16 k.

　　On both ends of the bolt temperature from the intermediate section to reduce gradually, and along the outer diameter of flange cover to gradually reduce from the inside-out. Nut and flange interface in the highest temperature, this is because the temperature of the bolt and nut first is passed by the flanges here, in addition, flange material coefficient of thermal conductivity is bigger than bolt hole equivalent coefficient of thermal conductivity of air layer. Gasket stress along the radial distribution of the comparison operation conditions, the gasket seal pressure should not be below mP = 9 for gasket coefficient, take 3; P for the internal pressure, take 3 MPa).