PENGARUH WAKTU PENGELASAN TITIK (SPOT WELDING) TERHADAP KEKERASAN, KEKUATAN GESER DAN DIAMETER NUGGET PADA BAJA SPCEN 1,6 mm

The development of technology in manufacturing is currently very fast. One of the important processes involved is joining, including the process of resistance spot welding or better known as spot welding. The use of point welding has several advantages, including a neat shape of the joint, the process is faster, the connection is tighter and the operation is relatively easy and does not require filler metal. The connection of relatively thin plate-shaped steel using resistance spot welding is an alternative option that is widely used by the automotive parts production industry. However, there are no data regarding the best time and data regarding the hardness test, nugget diameter, and shear test on SPCEN steel material. This study aims to determine the effect of spot welding time on hardness, shear strength and nugget diameter on SPCEN steel material. This study used an experimental method with a time variable of 1 second, 2 seconds and 3 seconds with standard material SPCEN JIS G 3141, standard hardness testing using DIN 50103 and standard shear testing using ASTM D 1002. equal that is 3.3 mm. The lowest average nugget hardness results are found on steel plates marked with the name ABC, time of 1 second with an average nugget hardness of 116.6 HRB and the highest average nugget hardness is found on GHI steel within 3 seconds with an average nugget hardness of 117 , 9 HRB. The lowest average yield of shear strength is found in ABC steel at 1 second with a maximum shear strength of 294.82 N / m² and a maximum load of 1592.01 Newton, the highest average yield of shear strength is found on steel plates marked with the name GHI time 3 seconds with a maximum tension of 415.89 N / m² and a maximum load of 2245.83 Newton. Thus the longer the spot welding time (spot welding), the greater the current used, the greater the heat generated and the hardness and shear strength become stronger. Shows the best time for spot welding (spot welding) of 1.6 mm SPCEN steel plate in 3 seconds.

Parametric investigation into fatigue life behaviour of spot welded tensile shear test samples

Resistance spot welding is a widely used joining process in the structural components of various engineering products such as white goods, aerospace equipment and especially automobiles. Hence it is crucial that the mechanical performance of such joints be well understood in order to design and manufacture reliable engineering products. In service, Spot-welded joints undergo fatigue failure under cyclic loadings. In order to examine and improve the fatigue life of spot welded structures, various assessment methods have been used on standardized test samples such as tensile shear (TS), modified tensile shear (MTS), coach peel (CP) and modified coach peel (MCP) specimens. The fatigue life studies have shown that among the most important design variables for spot-welded structures influencing joint strengths, sheet thickness, spot weld nugget diameter, number of spot welds and the joint type can be counted. In this study, a numerical examination was carried out to observe the effects of sheet thickness and nugget diameter on the fatigue life of tensile shear (TS) samples. In the analysis both Morrows mean stress and Coffin Manson approach were utilized. The performance of both methods was verified on the basis of experimental data available in literature. The elastic and plastic strains necessary for the calculations were found out by means of finite element method. The results presented herein provide variation of fatigue life predictions according to selected geometry parameters along with valuable interpretations that can be used as guidelines for designers.

Influence of electrode tip diameter on metallurgical and mechanical aspects of spot welded duplex stainless steel

In this article, the influence of electrode tip diameter is investigated for spot welded duplex stainless steel (DSS). Electrode tip diameter and welding current are considered as the major influencing parameters and their values are varied within the feasible range, suitable for 0.8 mm thick sheet, whereas other important parameters such as welding time and electrode force are kept constant. DSS with the chosen thickness range is now becoming a useful material in automotive body-in-white applications and in future it will become one of the key materials replacing the existing materials and hence research outcome of the present work may be beneficial from application view point. In this work, the spot welding quality is inspected through metallurgical aspects (microstructure and microhardness), physical aspects (nugget diameter and electrode indentation), mechanical performance (tensile shear strength [TSS]) and failure mode. The obtained result shows that smaller electrode tip diameter limits nugget diameter due to expulsion phenomena and increases electrode indentation due to higher current intensity. TSS decreases with increase in electrode tip diameter for the same welding current but maximum TSS obtained for particular electrode tip diameter increases with increase in electrode tip diameter up to a specific limit and then it remains constant.

Prediction of the Weld Qualities Using Surface Appearance Image in Resistance Spot Welding

The quality of the resistance spot weld is predicted qualitatively using information from the weld’s external apparent image. The predicting tool used for weld qualities was a convolution neural network (CNN) algorithm with excellent performance in pattern recognition. A heat trace image of the weld surface was used as information on the external apparent image of welds. The materials used in the experiment were advanced high strength steel (AHSS) with 980 MPa strength, and uncoated cold-rolled (CR) steel sheets and galvannealed (GA) steel sheets were used. The quantitatively predicted weld quality information contained tensile shear strength, nugget diameter, fracture mode of welds, and expulsion occurrence. The predicted performance of the verification step of the model determined through the learning process was as follows; the predicted error rate for tensile shear strength and nugget diameter were 2.2% and 2.6%, respectively. And the predicted accuracy on fracture mode and expulsion occurrence was 100%.