Conditions of Both Side Heating Method and Its Control Procedure

Development of Stress Control Method for Pipe Batt Weld Joint (2)

Abstract

Both side heating method which is proposed by authors in previous report is the effective stress control method for pipe butt weld joint. Non-dimensional parameters that control the effect of this method, and conditions which should be satisfied to get sufficient effect in actual application are clarified in this paper. Followings are the rusults which are made clear in this paper.
(1) The parameters which control effect of both side heating are βl, βW and K (=σ/EαT). Where β, l and W are size parameter (β⁴=3(1-υ²)/r²t²), distance from weld center line and width of heating region, and r, t, σ, E, υ, a and T are radius of pipe, thickness, stress at joint region, Young's modulus, Poisson ratio, thermal expansion coefficient, and temperature difference. The relation between parameters βl, βW and non-dimensional stress K are figured out, and this relation shows the combination of parameter range which control the residual stress at weld inside to compression state. These parameters and the combination of their ranges are verified by FEM analysis.
(2) The locations of temperature measurement and the conditions of temperature at each location which should be satisfied to get sufficient effect in actual application are proposed. These conditions for actual application are verified through experiment of both side heating on two size of stainless steel pipe weld joints based on the proposed condition.