JEMMME, Vol.3, No. 2, November 2018 ISSN 2541-6332 e-ISSN 2548-4281 JEMMME | Journal of Energy, Mechanical, Material, and Manufacturing Engineering 113 The Influence of Welding Ampere Range to ST-40 Shear Strength with Butt Joint Rudi Winarnoa, Daryonob, M. Jufric a, b, cMechanical Engineering, University of Muhammadiyah Malang Jl. Raya Tlogomas No. 246 Telp. (0341) 464318-128 Fax. (0341) 460782 Malang Email: Rudiwinarno94@gmail.com, daryono@umm.ac.id, jufri@umm.ac.id Abstract This experiment was conducted on the influence of welding process with ampere range variation and weld joints toward ST-40 shear strength. Furthermore, welded specimen is tested with tensile test. Method of this experiment is testing shear strength by using tensile testing machine where each five-specimens were previously welded by ampere range of 80 A, 90 A, and 100 A. Shear results show the highest shear strength is on 128.4916 N/mm2 with 80-ampere range on specimen no. 5, while on 90-ampere range variation the highest shear strength is on 124.7528 N/mm2, the specimen no. 5. Meanwhile, on 100-ampere range variation, the highest shear strength is on 120.1484 N/mm2, the specimen no. 4. The higher ampere (I) used, the higher heat (Q) resulted. When the heat increases, the welding electrode is perfectly fused. It makes good welding result achieved. The more strength on welding result, the higher shear strength (τ) achieved. On the other hand, the higher ampere range on welding process results higher shear strength. Keywords: welding; ampere range; shear strength 1. INTRODUCTION Many factors can influence welding result [1], namely method and procedure of welding, equipment, materials needed, electrode, ampere range applied, seam distance, and seam angle applied [2][3]. Ampere range and seam angle are considered to be experimented. Variation on ampere range and seam type for welding are determined to achieve stronger and better welding result [4]. Testing on welding area is divided into two, destructive and non-destructive tests [5]. Destructive test is conducting by giving tensile test to welded material. Tensile test is method aimed to examine material strength by giving linear load. By pulling a material, its reaction to pulling force would be recognized. Moreover, it would show its elongation during it is pulled. Experimental instrument for this tensile test should have strong grip and highly stiff. 2. METHOD Shear strength was conducted by ampere range variation of 80A, 90A, and 100A. Materials used for this experiment is ST40 steel plate with ASTM E8 cutting standard [6]. It is 200 mm length, 50 mm wide, and 5 mm thickness. Welding process conducted on ampere range variation [7][8] of 80 A, 90 A and 100 A. Shear strength conducted is using tensile test. Collected data is analyzed to achieve deduction of the test result. 2.1 Research variable Variable is research object or the focus of research. Variable in this experiment is quantitative variable that has correlation to seam type and the use of ampere range of 80A, 90 A and 100A. Variables of experiment are dependent and independent variables. mailto:Rudiwinarno94@gmail.com mailto:daryono@umm.ac.id mailto:jufri@umm.ac.id JEMMME, Vol.3, No. 2, November 2018 ISSN 2541-6332 e-ISSN 2548-4281 JEMMME | Journal of Energy, Mechanical, Material, and Manufacturing Engineering 114 2.1.1 Independent variable Independent variable is the influencing variable and it can be varied as the researcher needs [9]. In this experiment, independent variable used based on machine capacity is: 1. Ampere range 1 : five specimens are welded in 80 Ampere 2. Ampere range 2 : five specimens are welded in 90 Ampere 3. Ampere range 3 : five specimens are welded in 100 Ampere 2.1.2 Dependent variable Dependent variable is variable with no change in this experiment, it is fixed [9]. Dependent variable in this study is shear strength on welding joint. 2.2 Time and place of experiment This experiment was conducted in Metal Testing Laboratory Mechanical Engineering University of Muhammadiyah Malang. 2.3 Material and equipment 2.3.1 Materials 1. ST40 steel 2. RB26 electrode with 2,6 mm diameter Tensile test specimen Shape and size of object for tensile test based on ASTM E8/E8M standard Figure 1. ASTM E8 Specimen standard Table 2. Dimension of tensile test work-piece 2.3.2 Equipment 1. Electrical welding 7. Handled hand files 2. Hand grinding 8. Vice tool 3. Hacksaw 9.Jangka sorong 4. Welding mask 10.Penggaris 5. Hammer slag 11. Peralatan uji tarik 6. Steel brush JEMMME, Vol.3, No. 2, November 2018 ISSN 2541-6332 e-ISSN 2548-4281 JEMMME | Journal of Energy, Mechanical, Material, and Manufacturing Engineering 115 3. RESULT AND DISCUSSION Research data Experiment materials : ST40 steel plate Length : 200 mm Width : 50 mm Thickness : 5 mm Ampere range variation : 80A, 90A, 100A Figure 2. Work-piece Result of shear strength Experiment conducted in Metal Testing Laboratory Mechanical Engineering University of Muhammadiyah Malang results loading graphs of shear strength. Each specimen of shear strength conducted to obtain shear strength value. Table 2. Fracture results of shear test No Ampere range No. Specimen Fracture Explanation 1 Parent metal fracture 2 Parent metal fracture 1 80A 3 Parent metal fracture 4 Parent metal fracture 5 Parent metal fracture 1 Parent metal fracture 2 Parent metal fracture 2 90A 3 Parent metal fracture 4 Parent metal fracture 5 Parent metal fracture 1 Parent metal fracture 2 Parent metal fracture 3 100A 3 Parent metal fracture 4 Parent metal fracture 5 Parent metal fracture JEMMME, Vol.3, No. 2, November 2018 ISSN 2541-6332 e-ISSN 2548-4281 JEMMME | Journal of Energy, Mechanical, Material, and Manufacturing Engineering 116 80 Ampere Specimen 1 Plate thickness (t) : 5 mm Plate width (L) : 50 mm Welding width (l) : 5 mm Welding length (p) : 50 mm Maximum loading (F) : 25.3282 KN/mm2 Fracture load : 17.6550 KN/mm2 a. Tensile stress A = thickness x width = 5 x 50 = 250 mm2 Figure 3. Plate cross-section σt = 𝐹 𝐴 σt = 25.3282 250 = 0.1013128 KN/mm2 = 101.3128 N/mm2 b. Tensile stress and electrode shear stress - Electrode tensile stress σelectrode = 60000 Psi = 413 N/mm2 - Electrode shear stress τs = 0.6 x electrode tensile stress = 0.6 x 413 = 247.8 N/mm2 Table 3. Result of shear strain No Ampere range Fracture load (KN) F max (kN) τs= F/A (KN/mm) 1 80 17.655 25.3282 101.3128 2 80 18.3602 31.0532 124.2128 3 80 16.1528 26.3969 105.5876 4 80 18.997 30.5134 122.0536 5 80 19.6604 32.1129 128.4916 Average 116.33168 1 90 17.6916 24.8725 99.49 2 90 19.1639 30.5356 122.1424 3 90 19.6585 28.9852 115.9408 4 90 18.2575 27.0535 108.214 5 90 18.8675 31.1882 124.7528 Average 114.108 JEMMME, Vol.3, No. 2, November 2018 ISSN 2541-6332 e-ISSN 2548-4281 JEMMME | Journal of Energy, Mechanical, Material, and Manufacturing Engineering 117 Table 3. Result of shear strain (continued) No Ampere range Fracture load (KN) F max (kN) τs= F/A (KN/mm) 1 100 18.0751 30.0005 120.002 2 100 19.3039 30.0131 120.052 3 100 19.3125 27.4896 109.9584 4 100 19.048 30.0371 120.1484 5 100 17.2327 29.2879 117.1516 Average 117.46248 0 Graphic 1. Data of shear strength calculation Analysis on shear strength results  Result of shear stress shows that the highest value of 128.4916 N/mm2 is on 80 ampere in specimen 5. Meanwhile, in 90 ampere range, the highest shear strength is 124.7528 N/mm2 in specimen 5. Moreover, 100 ampere range variation shows the highest value 120.1484 N/mm2 in specimen 4. The higher ampere range applied, the heat is higher. Pressure on electrode formed the welding joint. Yet, it is not always that increasing current will result better joint. There is a condition where the higher current will damage the welding result. It occurs because the melting point of each materials is different. If heat resulted exceeded the melting point of material, it would result the defecting welding joint.  Fracture occurs in shear strength with tensile test is not damaging the welding joint but in parent metal. Shear strength with maximum load on 80-ampere variation has tensile strength of 128.4916 N/mm2. It is defected on parent metal. Meanwhile, maximum tensile strength on ST40 steel before treatment is 461.6 N/mm2. With maximum tensile strength of 128.4916 N/mm2, the specimen should not be fractured. As the tension is not exceeding maximum tensile stress of parent metal, the fracture occurs because of JEMMME, Vol.3, No. 2, November 2018 ISSN 2541-6332 e-ISSN 2548-4281 JEMMME | Journal of Energy, Mechanical, Material, and Manufacturing Engineering 118 tension concentration on the tested specimen. Therefore, tension concentration triggered excess breakage and fracture on low load.  Meanwhile, observed from tensile strength of welding electrode, its maximum value is 413 N/mm2 and shear strength is 247.8 N/mm2. The weld is not defected. It can be explained that maximum load on welding area is designed on the joint to have maximum shear strength of 128,4916 N/mm2. This value is still smaller than shear strength of electrode material.  As it is recognized, welded metal can be categorized into three; they are base metal (initial tested object). It is parent metal where heat and temperature of welding is not causing change on structure of metal characteristic. The second is Heat affected zone, it is basic metal adjacent to parent metal, which during welding process encounters heat thermal cycle and fast cooling that this area is being the most critical of welding joint. The third is Weld metal. It is the part of metal that in welding process, it melts and freezes up. Welding composition consists of parent metal and other materials from electrode. Fracture in welding area is the best fracture during shear strength because this area has high repetition heating. 4. CONCLUSION From the result of testing, it can be concluded that ampere range variation has no correlation to shear strength of butt joint welding. What had been occurred in this test is pure tensile strength. Welding process is too long that when the specimen has tensile test, the parent metal is breakage or fractured. Specimen is improved by adding radius and length of area. The seam is also improved to develop further research. REFERENCES [1] Ghazvinloo HR, Honarbakhsh-Raouf A, Shadfar N. Effect of arc voltage, welding current and welding speed on fatigue life, impact energy and bead penetration of AA6061 joints produced by robotic MIG welding. Indian J Sci Technol. 2010; [2] Tewari SP, Gupta A, Prakash J. Effect of the Welding Parameters on the Weldability of Material. 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