A Comparative Study on Tensile Strength, Hardness, and Microstructure at ST.42 Steel Plate Welded with Electric and Acetylene Welding

摘要

This study aims to determine the physical and mechanical properties of the steel plate welded ST.42 after using electric and acetylene welding. It is also to know the difference in tensile strength, hardness, and microstructure on ST.42 steel plate welded in both welding process. The research data was obtained with experimental methods by comparing the tensile strength, hardness, and microstructure for both welding process and was tested by using universal testing tool such as Vickers hardness test and digital microscope. Data were analyzed with descriptive statistics and inferential statistics. The object of this study was ST.42 steel available in the market. Results of the data analysis showed that there is no significant difference between the tensile strength, Vickers hardness numbers, and the microstructure of the steel grain pearlite and ferrite results for both electric and acetylene welding on steel plate ST.42. The magnitude of the tensile strength of electric welding had maximum tensile strength of 361.1460 kg/mm~2 with a maximum tensile force of 115.5667 N. The amount of tensile strength through Oxyacetylene welding had a maximum tensile strength of 58.2500 kg/mm~2 with a maximum tensile force of 18.6400 N. The magnitude of Vickers hardness number of electric welding was in average of 936.5443 HV. On the other hand, Vickers hardness number of Oxyacetylene was in average of 902.5220 HV. The results of microstructure through electric welding were 66.8496 μm for steel grain pearlite and 29.3485 μm for steel grain pearlite. The amount of those of Oxyacetylene welding were 58.5267 μm for steel grain pearlite and 29.3585 μm for grain ferrite steel.