Prediction of Fillet Weld Penetration (Report 1)

Fundamental investigation and practical application to shallow penetration of fillet welds

Abstract

Fundamental equations and diagrams of welding penetration are obtained from idealised models of a moving point heat source, and practical application of the theoretical penetration is investigated to predict actual penetration of a fillet welding joint as follows:
(1) Relationship between-welding conditions represented by dimentionless function N and theoretical penetration represented by dimentionless function D is given by the following equations with common parameter ρ:
N=ρ⋅exp(ρ/1+ρ), D=ρ/1+ρ√1+2ρ
N-D diagram obtained from the two equations above is presented as shown in Fig. 2.
(2) Temperature distribution of a infinite plate being welded on both sides simultaneously. is also investigated, and the relationships of welding conditions (N), plate thickness (T) and-theoretical penetration (D) are given by the following approximate dimensionless equations:
1/N=1/ρ⋅exp(ρ/1+ρ)+1/R⋅exp(R-ρ²/1+ρ)
R=√(T-D)²+(ρ²/1+ρ)²
D=ρ1+ρ√1+2ρ
N-D-T diagram and D-T diagram are obtained from the three. equations above as shown in Fig. 4 and Fig. 5 respectively for practical application td simultaneous fillet welding on both sides of a Tee-joint.
(3) Relationship between norminal penetration (d) of actual fillet weld and theoretical penetration
(d) obtained from N-D diagram or N-D-T diagram is given by the following approximate equation (see Fig. 7 and Fig. 8):
d=2.36(d2/h-h/2π)
where, h is leg size of a fillet weld.
(4) Relationships between nominal penetration (d) and effedtive penetration (p) of a fillet welding joint (see Fig. 6) are also given approximately as follows:
for single fillet welding ........................... Ψ1=√(δ+1)(5.828δ-1)-2.414δ
for both-sides welding ........................... Ψ2=1/2δ{√(0.157+1.63δ²)(0.1570.37δ²)-0.157+ δ²}
where, Ψ=p/h, δ=d/h
Ψ-δ diagrams are presented to predict effective penetration as shown in Fig. 13.
(5) The utility of the results shown above is experimentally confirmed by automatic contact arc welding of Tee joint. (see Figs. 9, 10 and 13)
The present paper discusses mainly on shallow penetration of fillet welds, the deep penetration will be discussed in 2 nd report.