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Microstructure and Mechanical Properties of AISI 1106 /AISI 1045 Steels Drawn Arc Stud Welded Joints

100%

Algodi S. J. , Salman A. A. , Al-helli A. H.

tom Vol. 17, no 5

48--55

Arc stud welding process was used to join a fully threaded low carbon steel AISI 1106 stud to medium carbon steel AISI 1045 plate, the effects of welding current 200, 400 A and the welding time 0.1 to 0.6 step 0.1 s on the microstructure and mechanical properties were investigated, additional parameters of adding 0.1, 1 g SiC powder and applying nano carbon layer to the welding area also included. The results demonstrate that the preferred stud welding process parameters for this system was 400 A with 0.4 s welding current and time, respectively, which has a maximum tensile strength of 583 MPa. The joints fabricated with ash and nano carbon coated at preferred welding parameters showed a slight reduction in tensile strength. The fracture of the tensile test specimen consists of three failure modes including of interface fracture between stud and plate surface due to incomplete melting at low processing parameter, pullout fracture which is featured by a hole in the plate surface and fracture at the stud shank instead of the weldment interface or heat affected zone. The microstructure of the stud and plate are characterized by equiaxed grain of ferrite and pearlite with small amount of ferrite, respectively. The fusion zone consists of fine grain of ferrite and perlite. The hardness of the fusion zone was recording 132 HV which it slightly higher than the stud hardness 128 HV and lower than that of plate of 164 HV.

A computational fluid dynamics analysis of transport enforced by Marangoni effect during laser welding

100%

Siwek A.

tom Vol. 17, No. 4

186--194

The presence of surface active elements such as sulfur in steel, changes the surface tension on the weld pool surface. The Marangoni effect induced by temperature dependent surface tension gradient, determines the direction of fluid flow in the entire volume of the weld pool. The difference of initial sulfur concentration of the welded parts is an additional factor which complicates the model. During welding an additional body force source term has been added to the momentum equations at the liquid steel surface, depending on sulfur concentration gradient. Mutual mixing of welded steels in the weld pool leads to periodic changes of driving force direction. The model permits the calculation of sulfur concentration in the weld pool and weld size depending on the initial composition, laser power and welding velocity.

Wpływ zawartości siarki na proces spawania opisany został w wielu pracach. Siarka jako jeden z pierwiastków powierzchniowo aktywnych wpływa na napięcie powierzchniowe stali. W większości publikacji dotyczących modelowania procesu spawania, zawartość siarki była taka sama w obydwu spawanych elementach. Artykuł dotyczy przypadku, gdy spawane stalowe elementy różnią się zawartością siarki. Mieszanie się spawanych stali w jeziorku spawalniczym prowadzi do okresowych zmian kierunku działania siły wymuszającej przepływ. Model pozwala na obliczenie rozkładu zawartości siarki w spoinie oraz wielkości spoiny w zależności od danych termofizycznych stali, początkowej zawartości siarki, mocy wiązki lasera i prędkości spawania.

51%

Węgrzyn T. , Szczucka-Lasota B. , Krzysztoforski M. , Śliwiński T.

2024

tom z. 195

593--600

Purpose: Main novelty and the aim of the paper is to analyses possibility of dissimilar AG welding of two various grades of steel with significantly different structure. Design/methodology/approach: Two various metals have been checked in welding in order to obtain a high-quality joint of car body elements. The properties of the joint were checked by NDT (Non Destructive Test) and DT (Destructive Tests). Findings: Relations between MAG welding process parameters and the quality of joint. Research limitations/implications: In the future, it can be tested the effect of micro addition of nitrogen or oxygen in gas shielding mixtures of the MAG process. Practical implications: Suggested materials and innovation will not cause problems in the production process provided that the technological regime will be respected. Social implications: Modifying the welding materials and method will not affect the environment and production management methods. Producing of dissimilar welds must translate into production savings. Originality/value: The paper is addressed to manufacturers of low-alloy and advanced high strenth steel for automotive industry.