Influence of welding parameters on residual stresses in dissimilar HSLA steels welds

For many years, the use of high strength steels in construction is increasing due to high ratio of strength to weight and cost considerations. These properties reduce the fabrication cost and time. To make use of these advantages of these modern steels, their weldability was extensively evaluated. In the present study a dissimilar patch welds between two high strength steels was investigated. A series of dissimilar steel joints based on the S600MC (as the base plate) and S355 (as the patch plate) were produced using robotic MIG welding. Residual stresses were determined using the X-ray diffraction (XRD).The effect of welding speed and sequence on residual stresses distribution in two different patch shapes was studied. Analysis of the results revealed that using of the welds in opposite directions reduces the welding stresses and the effect of welding speed is different in two patch shapes. It was found final state of residual stresses depends on all of theses parameters

Influence of welding parameters on residual stresses in dissimilar HSLA steels welds

For many years, the use of high strength steels in construction is increasing due to high ratio of strength to weight and cost considerations. These properties reduce the fabrication cost and time. To make use of these advantages of these modern steels, their weldability was extensively evaluated. In the present study a dissimilar patch welds between two high strength steels was investigated. A series of dissimilar steel joints based on the S600MC (as the base plate) and S355 (as the patch plate) were produced using robotic MIG welding. Residual stresses were determined using the X-ray diffraction (XRD).The effect of welding speed and sequence on residual stresses distribution in two different patch shapes was studied. Analysis of the results revealed that using of the welds in opposite directions reduces the welding stresses and the effect of welding speed is different in two patch shapes. It was found final state of residual stresses depends on all of theses parameters

Tryb uszkodzenia zgrzewanych spoin stali HSLA 420

Failure mode of resistance spot welds (interfacial vs. pullout) is a qualitative measure of resistance spot weld performance. Considering adverse effect of interfacial failure mode on the vehicle crashworthiness, process parameters should be adjusted so that the pullout failure mode is guaranteed ensuring reliability of spot welds during vehicle lifetime. In this paper, metallurgical and mechanical properties of HSLA 420 resistance spot welds are studied with particular attention to the failure mode. Results showed that the conventional weld size recommendation of 4t0:5 (t is sheet thickness) is not sufficient to guarantee pullout failure mode for HSLA steel spot welds during the tensile-shear test. Considering the failure mechanism of spot welds during the tensileshear test, minimum required fusion zone size to ensure the pullout failure mode was estimated using an analytical model. Fusion zone size proved to be the most important controlling factor for peak load and energy absorption of HSLA 420 resistance spot weld.Tryb uszkodzenia zgrzein (pękanie na granicy faz a wyrywanie) jest jakościowa miara zachowania zgrzein. Biorąc pod uwagę niekorzystny wpływ uszkodzenia na granicy faz na odporność pojazdu na uderzenia, parametry zgrzewania powinny być ustawione tak, ze trybem uszkodzenia jest wyrywanie co gwarantuje niezawodność zgrzein w czasie eksploatacji pojazdu. W pracy, badane sa metalurgiczne i mechaniczne właściwości zgrzein stali HSLA 420 ze szczególnym uwzględnieniem trybu uszkodzenia. Wyniki próby rozciągania i ścinania wykazały, ze konwencjonalne zalecenie rozmiaru spoiny 4t0:5 (t - grubość) nie jest wystarczające, aby zapewnić ze trybem uszkodzenia jest wyrywanie. Biorąc pod uwagę mechanizm uszkodzenia zgrzein w czasie próby rozciągania i ścinania, minimalna wielkość strefy stopionej wymagana do zapewnienia, ze trybem uszkodzenia jest najbardziej istotnym czynnikiem decydującym o maksymalnym obciążeniu i pochłanianiu energii przez zgrzewana stal HSLA 420