The present paper is concerned with the residual stresses and deformations caused by a circumferential and/or longitudinal welding of thin-walled cylindrical shell of mean radius α, wall thickness h arid length l. Based upon experimental data by GMA welding process and analytical results by the previous papers, controlling parameters or combined effect of heat input and size of cylinder on the residual stresses and deformations are discussed.
In the circumferential-welded cylinders, the residual stresses σθ/σy, σx/σy in circumferential and longitudinal directions and deflections ω/aεy at a distance x/√ah from the weld centerline are determined by the two parameters,
Heat input parameter Hθ=Q/cρh√ah
Size parameter βθ=l/√ah
, where σy, εy, c and ρ are yield stress, yield strain, specific heat and density of the material respectively, and Q is net heat input per unit weld length. When the size parameter βθ exceeds a critical value, (βθ)cr, depending upon the heat input parameter Hθ, the residual stresses and deformations are determined uniquely by the heat input parameter Hθ.
In the longitudinal-welded cylinders, the residual stresses σx/σy, σθ/σy, and deflections √h/aω/lεy at an angle θ from the weld centerline on the mid-cross seetion are decided by the parameters,
Heat input parameter Hx=Q/2cρπah
Size parameter βx=(l/a)√h/a
In the range that the size parameter βx is larger than its critical value, (βx)rc≅3, only one controlling parameter is the heat input parameter Hx.
When the size parameters exceed their critical value, the residual stresses and deflections are expressed as functions of the heat input parameters. The calculated values are approximately agreed with the experimental results.
