Performance analysis of a pneumatic to servo converted system for electrode actuation in resistance spot welding using 304L austenitic stainless steel

Abstract

A high current, AC waveform controller with C-type body frame of spot welder (75 kVA), was examined for the electrode actuating system whose pneumatically driven system has been redesigned and refitted for the servo based system without any vertical spring assistance in the 50 mm movable distance. Moreover, the pressing mechanism was carefully handled during the entire pressing tasks as to ensure that no catastrophic reaction happens for the electrodes’ caps, electrodes’ holders as well as the other part of mechanical assembly. With the mechanically originated-pneumatic and also the converted-servo systems, the stainless steels are welded for both systems to characterize the improvements. While the welding processes were carried out, the electrical signals have been captured to compute the signals’ representation of entire sequences. Later, the welded samples were underwent the tensile shear test, metallurgical observation and hardness test. The analytical results show distinct changes in the force profiles which has led to profound changes in mechanical properties of welded specimens.

Keywords

force profiles / electrode actuation system / servo and pneumatic system

References

[1] ChardeN. Analyzing the force and current profiles using pneumatic and servo based-electrode actuation system for resistance spot welding [J]. Caspian Journal of Applied Sciences Research, 2013, 2(8): 38-21

[2] ChardeN. Effect of spot welding variables on nugget size and bond strength of 304 austenitic stainless steel (2 mm) [J]. Australasian Welding Journal, 2012, 57: 1-7

[3] ChardeN. Spot weld growth on 304L austenitic stainless steel for equal and unequal thicknesses [J]. Caspian Journal of Applied Sciences Research, 2012, 1(11): 79-87

[4] ChaB W, NaS J. A study on the relationship between welding conditions and residual stress of resistance spot welded 304-type stainless steels [J]. Journal of Manufacturing Systems, 2003, 223: 344-353

[5] PouranvariM, MarashibS, PH. Failure mode transition in AHSS resistance spot welds, Part I: Controlling factors [J]. Materials Science and Engineering A, 2011, 528: 8337-8343

[6] WeiLEE. The influences of nugget diameter on the mechanical properties and the failure mode of resistance spot-welded meta stable austenitic stainless steel [J]. Materials and Design, 2012, 33: 292-299

[7] TangH, HouW, HuSJ, ZhangHY, FengZ, KimchiM. Influence of welding machine mechanical characteristics on the resistance spot welding process and weld quality [J]. Welding Journal, 2003133s-140s

[8] WeiP S, WuT H. Effects of electrode contact condition on electrical dynamic resistance during resistance spot welding [J]. Science and Technology of Welding and Joining, 2014, 19(2): 173-180

[9] FukumotoS. Small scale resistance spot welding of austenitic stainless steels [J]. Materials Science and Engineering A, 2008, 492: 243-249

[10] DursunO. An effect of weld current and weld atmosphere on the resistance spot weld ability of 304L austenitic stainless steel [J]. Materials and Design, 2008, 29: 597-603

[11] FeramuzK. The effect of process parameter on the properties of spot welded cold deformed AISI304 grade austenitic stainless steel [J]. Journal of Materials Processing Technology, 2009, 209: 4011-4019

[12] BayraktarE, MoironJ, KaplanD. Effect of welding conditions on the formability characteristics of thin sheet steels: Mechanical and metallurgical effects [J]. Journal of Materials Processing Technology, 2006, 175: 20-26

[13] SenkaraJ, ZhangH, HuS J. Expulsion prediction in resistance spot welding [J]. Welding Journal, 2004120s-128s

[14] SHIH.. Input electrical impedance as quality monitoring signature for characterizing resistance spot welding [J]. NDT&E International, 2010, 43: 200-205

[15] ChangB H, ZhouY. Numerical study on the effect of electrode force in small-scale resistance spot welding [J]. Journal of Materials Processing Technology, 2003, 139: 635-641

[16] TangH, HouW, HuS J. Forging force in resistance spot welding [J]. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 2002, 216: 957-965

[17] JamasriT, IlmanM N, SoekrisnoR. Comparative study of fatigue assessment methods with and without considering residual stress on resistance spot-welded unequal sheet thickness stainless steel [J]. International Journal of Engineering and Technology, 2009, 11: 456-462

[18] InoueA H. Solidification and transformation behaviour of austenitic stainless steel weld metals solidified as primary ferrite: Study of solidification and subsequent transformation of Cr-Ni stainless steel weld metals [J]. Journal of the Japan Welding Society, 1997, 2(1): 88-99

[19] DancetteS, FabregueD, MassardierV, MerlinJ, DupuyT, BouzekriM. Investigation of the tensile shear fracture of advanced high strength steel spot welds [J]. Engineering Failure Analysis, 2012, 25: 112-122

[20] IsaevA P. A method for modeling the pneumatic drive and load carrying structure of resistance spot welding machines [J]. Svarochnoe Proizvodstvo, 2006, 59(3): 18-25

[21] ChangB H, DuD, SuiB. Effect of forging force on fatigue behavior of spot welded joints of aluminum alloy 5182 [J]. Journal of Manufacturing Science and Engineering, 2006, 1: 345-352

[22] IkedaR, OkitaY, OnoM, YasudaK, TerasakiT. Development of advanced spot welding process using control of electrode force and welding current during welding [J]. Journal of the Japan Welding Society, 2006, 28(1): 141-148

[23] SpinelliJ E. Microstructure and solidification thermal parameters in thin strip continuous casting of a stainless steel [J]. Journal of Materials Processing Technology, 2004, 150: 255-262

[24] HuangF X. In situ observation of solidification process of AISI 304 austenitic stainless steel [J]. Journal of Iron and Steel Research, 2008, 15(6): 78-82

[25] YongB L, ZeY W, YaT L, QiS, ZhongQ L. Effects of cone angle of truncated electrode on heat and mass transfer in resistance spot welding [J]. International Journal of Heat and Mass Transfer, 2013, 65: 400-408