Mechanical Behaviour and Strength of Front Fillet Welded Joint

Abstract

In the previous paper, theoretical evaluation on the strength of fillet welded joint was presented and compared with the experimental results. Theoretical value agreed well with the test results obtained by using model specimens machined from a homogeneous mild steel sheet. But in the welded joints, mechanical properties of weld metal and heat-affected zone are different from those of base metal. So the mechanical behaviour and the strength of fillet welded joint will be different from those of model specimen.
In this paper the mechanical behaviour and the strength of the front fillet welded joints are explained experimentally and theoretically. Experiments are made with four typical types of front fillet welded joints as follows;
1. Double Tee fillet welded joint.
2. Double strapped fillet welded joint.
3. Double Tee fillet welded joint including soft or hard weld metal.
4. Partial penetration groove welded joint.
The results obtained are as follows.
1. Fracture mode of fillet weld is affected by the strength and work hardening properties of weld metal (cf. Photo 1).
2. The strength of front fillet welded joint can be calculated by using the equation (2), (3), or (4) which are given by theoretical analysis.
3. The strength of front fillet welded joint including soft or hard weld metal can be estimated by using the equivalent weld metal strength σ_we (cf. Fig. 15).
4. The friction between base plate and strapped plate has large influence on the strength of double strapped fillet welded joint (cf. Fig. 11, Fig.12).
5. The equation for evaluation of the strength of partial penetration groove welded joint is given by comparing the test results and the theoretical analysis.