Analisis Variasi Sudut kampuh V Pengelasan SMAW Arus 85 A Gerak melingkar Dengan Elektroda RB-26 Terhadap Kekuatan tarik Plat Baja ST 42

ABSTRAK Huda, Syamsul. 2016. Analisis Variasi Sudut Kampuh V Pengelasan SMAW Arus 85 A Gerak Melingkar Dengan Elektroda RB-26 Terhadap Kekuatan Tarik Plat Baja ST 42. Skripsi, Jurusan Teknik Mesin, Fakultas Teknik, Universitas Negeri Malang. Pembimbing: (1) Prihanto Tri Hutomo, S.T., M.T., (2) Drs. Yuni Sunarto, M.Pd Kata Kunci: Variasi Sudut Kampuh V, Nilai Uji Kekuatan Tarik, Jenis Patahan Penelitian yang dilakukan adalah menganalisis perbedaan variasi sudut kampuh V 500, sudut kampuh V 600, dan sudut kampuh V 700 dengan masing-masing sample sebanyak 3 buah sehingga berjumlah 9 buah sample uji. Parameter penelitian ini menggunakan pengelasan Las busur listrik (SMAW: Shielded Metal Arc Welding) yang merupakan proses pengelasan dimana panas dihasilkan dari busur nyala listrik terlindung dengan mempergunakan busur nyala listrik sebagai sumber panas pencair logam. Plat baja karbon rendah ST 42 tebal 8 mm sebagai bahan spesimen pengelasan dengan acuan spesimen uji tarik JIS Z 2201 no.13B, menggunakan arus 85 A elektroda RB-26 pengelasan gerak melingkar, serta uji yang digunakan adalah pengujian kekuatan tarik (Universal Testing Machine). Penelitian ini merupakan penelitian eksperimental, setelah dilakukan pengujian tarik didapat nilai kekuatan tarik yang bervariasi dengan analisis data One-Way Anova menunjukkan bahwa tidak memiliki nilai perbedaan kekuatan tarik yang signifikan dari masing-masing variasi sudut kampuh V penelitian, karena nilai F = 2,834 atau signifikansi 0,136 lebih besar dari pada 0,05. Nilai dari kekuatan tarik pada sudut kampuh V 600 memiliki hasil 47,721 kg/mm2, nilai ini merupakan hasil yang paling kecil dari pada variasi sudut-sudut kampuh yang lainnya. Mengacu nilai kekuatan tarik sudut kampuh V 600 memiliki nilai paling kecil ternyata analisa foto makro perpatahan (Fracture) sample kampuh V 600 C menunjukkan patahan jenis ulet. Sudut kampuh V 500 lebih tinggi nilainya yang menunjukkan hasil kekuatan tarik sebesar 47,86 kg/mm2, nilai ini meningkat 0,139 kg/mm2 dari pada sudut kampuh V 600, untuk sudut kampuh V 700 memiliki nilai kekuatan tarik yang paling tinggi dengan nilai kekuatan tariknya sebesar 48,56 kg/mm2. Nilai ini meningkat 0,7 kg/mm2 dari pada nilai kekuatan tarik sudut kampuh V 500, sedangkan selisih atau peningkatan kekuatan tarik sudut kampuh V 600 dengan 700 sebesar 0,839 kg/mm2. Patahan yang terjadi untuk sample 500 B dan 700 B adalah patahan jenis getas. ABSTRACT Huda, Syamsul. 2016. Analysis of SMAW Welding V-Groove Variation for Current of 85 Aand Circular Movement with RB-26 Electrode to the Tensile Strength of Steel Plate ST 42. Mini Thesis, Department of Mechanical Engineering, Faculty of Engineering, State University of Malang. Supervisors: (1) Prihanto Tri Hutomo, S.T., M.T., (2) Drs. Yuni Sunarto, M.Pd Keywords: V-Groove Variation, Score of Tensile Strength Test, Fracture Type The research that been conducted was analyzing about the difference between variation of V-groove 50o, V-groove 60o, and V-groove 70o with each sample consists of 3, then all sample was 9 test samples. Parameter in this research used SMAW(Shielded Metal Arc Welding), which was welding process where the heat resulted from protected arc current by using arc current as heat source of metal melting. Steel plate of low carbon ST 42 with 8 mm thickness used as welding specimen material with specimen reference of tensile strength was JIS Z 2201 no. 13B, using current of 85 A and RB-26 electrode with circular movement welding, also test that used in this research was tensile strength test (Universal Testing Machine). This research was experimental research. After it was conducted by tensile strength test, it was obtained various tensile strength scores. With data analysis of One-Way Anova, it showed that there was no significant difference of tensile strength score from each V-groove variation of the research, because F value = 2.834 or significance 0.136 was bigger than 0.05. Score from tensile strength to the V-groove 60o had result 47.721 kg/mm2, this score was the smallest score from other V-groove variation. Referring to the tensile strengthscore of V-groove 60o which had smallest score, in fact fracture macro photo analysis of V-groove 60o sample showed fracture type of though. V-groove 50o had higher score which showed tensile strength for 47.86 kg/mm2, this score improved for 0.139 kg/mm2 than V-groove 60o. For V-groove 70o had the highest tensile strength score with tensile strength score for 48.56 kg/mm2. This score improved 0.7 kg/mm2 than tensile strength of V-groove 50o. Meanwhile, the difference or improvement of tensile strength for V-groove 60o and 70o was 0.839 kg/mm2. Fracture that occurred for sample 50oB and 70oB was fracture type of brittle. Green Sand Mold is a type of molding in foundry sand raw material which has binder and contains water. Molding sand binder which commonly used is bentonite. Previous studies showed that bentonite is an ideal binder for sand molding, yet the price is quite high in the market. The production of coal burning ashes (fly ash) in Indonesia is high thus it makes the price of fly ash more economical and can be obtained easily. Bentonite and fly ash have similar CaO compound (clay). Based on this reason, theoretically, fly ash can be used as a binder in sand molding. This study aimed to analyze the use of fly ash as a binder mixture to the permeability, compressive strength and fluidity to form pre-experimental model of a one-shot case study. Green sand mold treatment was given binder content variation in the form of fly ash and bentonite. The pre test began with permeability testing. Permeability testing used permeability tester to determine the flowed air volume per minute (cm3/minutes). Compressive strength testing was used Universal Sand Strength to determine the ability of molds to withstand the pressure of the molten metal flow per unit area (N/cm2). Fluidity testing conducted by the Birmingham method. Through this method, it could be revealed the melted metal flow length (mm) which filled molds pattern with varying thickness. Based on this research, there were three important information. First, the value of the lowest permeability was owned by a sand mold with a mixture of 4% fly ash and 5% bentonite. It was caused by the similarity of bentonite and fly ash amount therefore the space between the grains of sand was narrower if it was filled by two binders. Although the permeability owned by this molds was low, but it had the most ideal permeability among the two other treatments (between 50–170 cm3/minutes). Second, the value of the compressive strength of all the sand mold was high (above 0–1.0 kg/cm2). High compressive strength affected disassembly difficulty but it avoid mold loss. However, the more fly ash added, the value of compressive strength was decreased. This was due to the excess of CaO content which made the cementing agent reaction was imperfect. Third, the results showed that the fluidity of all molds was not suit the pattern at all. It was caused by the low pouring temperature that affected viscosity metal, false flow, and cold plug