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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.

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tom Vol. 17, no 5

48--55

EN

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.

2

Effect of arc stud welding parameters on the microstructure and mechanical properties of AA6061 and AA5086 aluminium alloys

63%

Razzaq M. K. A. , Abood A. N.

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tom Vol. 108, nr 1

24--34

EN

Purpose: This paper aims to investigate the effect of arc stud welding (ASW) process parameters on the microstructure and mechanical properties of AA6061-T6 and AA5086-H116 joint. Design/methodology/approach: ASW process was done with argon as a shielding gas. Optical microscope (OM), scanning electron microscope (SEM), and X-Ray Diffraction (XRD) were employed to investigate the influence of welding current, welding time, and gas flow-rate on the microstructure of the fusion zone (FZ). Torque strength and Microhardness tests were used to evaluate the mechanical properties of the welded joints. Findings: OM and SEM showed a cellular dendritic structure with equiaxed zone and columnar dendritic are forming at welding zone and weld interface. XRD analysis showed the precipitation of Mg2Si and Al3Mg2 in the similar and dissimilar joints. Similar ASW of AA6061-T6/AA6061-T6 recorded 19 N.m torque strength, while dissimilar welding of AA6061-T6/AA5086-H116 registered 23 N.m. With increasing heat input, grains in Fusion Zone (FZ) and Heat Affected Zone (HAZ) coarsen and the hardness in both zones decreased. The hardness of similar weldments indicated a remarkable softening of FZ, while lower hardness values were registered in HAZ of dissimilar weldments. Softening of both weldments is due to the dissolution of the strengthening precipitates. Hot cracks exist with similar weldments, while no cracks evidence with dissimilar weldments. Research limitations/implications: The main challenge in this work was how to minimize porosity level and how to avoid hot crack in the FZ. Practical implications: The application of ASW with ceramic ferrule has an important role in different production areas such as; automobile industry, aircraft applications, and appliances industry. Originality/value: Study the effect of welding current, welding time, and gas flow-rate of ASW process on microstructure and mechanical properties of AA6061-T6 and AA5086-H116 joint.

3

Study of solidification behaviour and mechanical properties of arc stud welded AISI 316L stainless steel

63%

Abass M. H. , Alali M. S. , Abbas W. S. , Shehab A. A.

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tom Vol. 97, nr 1

5--14

EN

Purpose: This paper aims to investigate the impact of arc stud welding (ASW) process parameters on the microstructure and mechanical properties of AISI 316L stainless steel stud/plate joint. Design/methodology/approach: The weld performed using ASW machine. The influence of welding current and time on solidification mode and microstructure of the fusion zone (FZ) was investigated using optical microscope and scanning electron microscope (SEM). Microhardness and torque strength tests were utilised to evaluate the mechanical properties of the welding joint. Findings: The results showed that different solidification modes and microstructure were developed in the FZ. At 400 and 600 A welding currents with 0.2 s welding time, FZ microstructure characterised with single phase austenite or austenite as a primary phase. While with 800 A and 0.2 s, the microstructure consisted of ferrite as a primary phase. Highest hardness and maximum torque strength were recorded with 800 A. Solidification cracking was detected in the FZ at fully austenitic microstructure region. Research limitations/implications: The main challenge in this work was how to avoid the arc blow phenomenon, which is necessary to generate above 300 A. The formation of arc blow can affect negatively on mechanical and metallurgical properties of the weld. Practical implications: ASW of austenitic stainless steel are used in multiple industrial sectors such as heat exchangers, boilers, furnace, exhaust of nuclear power plant. Thus, controlling of solidification modes plays an important role in enhancing weld properties. Originality/value: Study the influence of welding current and time of ASW process on solidification modes, microstructure and mechanical properties of AISI 316 austenitic stainless steel stud/plate joint.