On the strength of stainless steel fillet welds

Abstract

This paper describes 24 tests performed on welded specimens made of 3 stainless steel grades: EN 1.4307 (304L) and EN 1.4404 (316L) austenitic grades and EN 1.4062 duplex grade. For each grade, tests were carried out parallel to the weld and along the transverse direction. The austenitic grades were welded using GMAW (MAG), while the duplex grades were welded using Gas Metal Arc Welding (GMAW) and Gas Tungsten Arc Welding (GTAW or TIG). After failure, the fracture surfaces were measured using Digital Image Correlation (DIC) and compared to measurements before testing. The results were compared to 70 experiments on welded stainless steel samples, gathered from the literature. A relatively high scatter was found among the different sources as well as differences between grades and loading directions. A reliability study was then performed in agreement with EN 1990EN :2002 Annex D on the complete experimental data pool and recommendations for the correlation factor βw are then provided.

Experimental Study on the Strength of Stainless Steel Fillet Welds

“…However, in the literature [18], it was shown that the effect of the mechanical properties of the welding consumable has an influence on the strength ratio. It is also evidenced herein by the comparison of the strength ratios of both austenitic grades showing an average strength ratio of 1.01 and 1.16 for the longitudinal direction for respectively the EN 1.4307 and 1.4404 grade, while both base metals exhibit very similar stress-strain behaviour [11].…”

“…The Vickers hardness measurements showed a relative constant hardness level in the base metal and weld metal with a maximum difference of 8%. More information on the welding procedure and the subsequent quality assessment can be found in [11].…”

“…This study and the ones included in [11,12] concentrates on fillet welds with two loading directions and three stainless steel grades i.e., two austenitic grades, EN 1.4307 (304L) and EN 1.4404 (316L), and one duplex grade, EN 1.4062. Half of the tests were carried out with the load perpendicular to the welds causing both normal stress σ (perpendicular to the weld plane) and shear stress τ (perpendicular to the weld throat axis) and the other half of the tests with the load parallel to the weld causing only shear stress τ// (parallel to the weld throat axis).…”

“…The two austenitic grades EN 1.4307 and EN 1.4404 exhibit a large ductility domain and significant strain hardening compared to the duplex grade EN 1.4062, which has a considerably higher yield strength (501 MPa compared to 284 MPa and 280 MPa for EN 1.4307 and for EN 1.4404, respectively) combined with a smaller but still considerable strain hardening domain. For more information on the stress-strain behaviour of stainless steel, the reader can refer to [11,15].…”

Numerical Investigations on the Fatigue Life of Lean Duplex Transverse Stiffeners in Bridges

“…Microstructural investigation was then achieved by cutting, polishing and etching the welded samples (see ferrite in dark and austenite in white contours in Figure 2). The microscopic images taken in the base metal (BM), heat affected zone (HAZ) and fusion zone (FZ) were processed according to ASTM E562, and the resulting ferrite content was compared to the recommendations as shown in Table 1 [13].…”