Hj. Yen et al., MEASUREMENT AND SIMULATION OF RESIDUAL-STRESS IN TYPE-304 WELD OVERLAY STAINLESS-STEEL PIPE, International journal of pressure vessels and piping, 60(3), 1994, pp. 271-283
Repair by welding overlay is a commonly used method mainly employed to
rebuild piping systems suffering from intergranular stress corrosion
cracking (IGSCC). It is desirable that the overlay welding technique,
by attaching an overlay weld to the pipe and sustaining a heat sink of
flowing water inside the pipe, induces a compressive residual stress
at the inner surface of the welded pipe for prevention of IGSCC. A bet
ter understanding of the effect of a welding overlay repair on the res
idual stresses at the inner and outer surfaces of weld overlay is thus
required. To obtain this understanding, it is necessary to investigat
e the distribution of residual stresses on the welded pipe. In this st
udy, the hole-drilling strain-gauge method was adopted to determine th
e residual stresses at the inner and outer surfaces of the weld overla
y pipe. The incremental drilling technique was used on pipes with outs
ide diameters of 267 mm. In addition, the Weld 3 code was applied to s
imulate the residual stress distribution for comparison and verificati
on with the measured results. The results obtained from the experiment
al and from the computational methods are in good agreement. The resid
ual stress at the inner surface of the pipe is compressive with a magn
itude approaching the yield stress of the material; that at the outer
surface is tensile, also with a magnitude close to yield stress but sm
aller than the compressive stress. The experimental residual stress ma
gnitude is generally greater than that from computation. This observat
ion can be attributed to several factors including applied mechanics,
temperature distribution, original residual stress, strain gauge locat
ion, mechanical grinding and the oxidation layer.