Fig. 5. Specimens of 1.6 mm thick, 1000mm long, of stainless steel (a) and aluminum
alloy (b) welded by conventional GTAW, severely buckled (upper), and welded by
LSND welding, buckle-free (lower). Completely buckle-free results (
f
= 0
) can be
achieved using optimized LSND welding technique on both stainless steel (c) and
aluminum alloy (d) specimens of 1.6 mm thick (Ref. 11)
The photographs in Fig. 5 show that the specimens of either stainless
steel (Fig. 5, a) or aluminum alloy (Fig. 5, b) welded conventionally (upper
photo) are severely buckled in all cases. But the specimens welded by use
of LSND welding (lower photo) are completely buckle-free and as flat as
before welding.
Comparisons are also given in Fig. c, d between the results of measured
deflections
f
on specimens of 1.6 mm thick welded conventionally using
GTAW and those welded using LSND welding technique for stainless steel
(Fig. 5, c) and aluminum alloy (Fig. 5, d). Completely buckle-free (
f
= 0
)
results were achieved when the optimized technological parameters for
LSND welding techniques were selected.
As demonstrated above, designers and manufacturers who suffer from
problems of buckling could now adopt a new idea that buckling is no
longer inevitable with LSND welding technique. Buckling can be prevented
completely and residual stresses can be reduced significantly or controlled
to a level lower than
σ
cr
at which buckling occurs.
Successful results in preventing buckling distortions were achieved in
manufacturing thin-walled jet engine cases of nickel base alloys, stainless
steels as well as rocket fuel tanks of aluminum alloys where the acceptable
allowance of residual buckling deflections
f
at a weld length of
L
should
be limited to the ratio of
f/L <
0
.
001
(Ref. 12).
ISSN 0236-3941. Вестник МГТУ им. Н.Э. Баумана. Сер. “Машиностроение”. 2005. № 4 97
