During the last few years, high-strength structural steels with yield strength of 960 MPa have come onto the market. Using these steels it is possible to make lighter and more effective structures, but the properties of these steels correspondingly deviate from the behavior of traditional structural steels. One of the differences in question is the softening of the heat affected zone of the weld. In this paper, non-load-carrying X-joint has been analyzed and the effect of the geometry or welding parameters.
During the last few years, high-strength structural steels with yield strength of 960 MPa have come onto the market. Using these steels it is possible to make lighter and more effective structures, but the properties of these steels correspondingly deviate from the behavior of traditional structural steels. One of the differences in question is the softening of the heat affected zone of the weld which causes a local decrease in the strength. The literature does not contain significant reports on the effect of the phenomenon in question on the steels with yield strength of 960 MPa. Attention must also be paid to the fact that the phenomenon affects the properties of the non-load-carrying welded joints, something which is not easily observed. EN 1993-1-8 NA in Finland is a document which takes the softening effect into account with high strength steels in the case of butt weld. In this paper, non-load-carrying X-joints were tested with different welding parameters to clarify this phenomenon and how to control it in real structures. The tests were done using a wide plate test target to get as realistic results as possible. Similar parallel specimens were done to measure hardness distribution in joints and also for making tensile testing specimens to evaluate material properties of joints.
