Analisa Pengaruh Variasi Heat Input Terhadap Cacat Pengelasan, Lebar Haz, Dan Kekerasan Pada Pengelasan Smaw Material Tembaga C81300

Tembaga merupakan salah satu logam yang sangat bermanfaat bagi kebutuhan teknologi maupun industri. Kemungkinan terjadinya penurunan kekuatan mekanis pada sambungan las, terjadi akibat pada bagian yang dilas mengalami perubahan struktur butiran logam akibat pemanasan dan pendinginan selama pengelasan. Dalam penelitian ini menggunakan material tembaga C81300, jenis las yang digunakan adalah Shielded Metal Arc Welding (SMAW). Proses pengelasan dibedakan berdasarkan variasi Heat input yaitu 1244.239 J/mm, 1306.452 J/mm, 1314.401 J/mm. Dengan posisi pengelasan 1G dan sambungan butt joint V-grove 70°. Electrode yang digunakan adalah NS 9050. Analasia hasil lasan ditinjau dari pengujian yang dilakukan, antara lain Uji Radiografi, Uji Makro, dan Uji Kekerasan. Hasil analisa didapat ketiga variasa lasan memiliki cacat porosity dan incomplete penetration. Lebar HAZ terbesar dimiliki hasil lasan dengan variasi Heat input yaitu 1314.401 J/mm. Nilai kekerasan daerah HAZ variasi lasan variasi 1244.239 J/mm memiliki nilai kekerasan tertinggi, dan variasi 1213.401 J/mm memiliki kekerasan terendah. =================================================================== Copper is one of the metals that is very useful for technological and industrial needs. The possibility of a decrease in mechanical strength at the welded joint, due to the welded part experiencing a change in the structure of the metal grain due to heating and cooling during welding. In this study using C81300 copper material, the type of welding used is Shielded Metal Arc Welding (SMAW). The welding process is distinguished based on the variation of the Heat input which is 1244,239 J/mm, 1306,452 J/mm, 1314,401 J/mm. With a 1G welding position and 70 ° butt joint V-grove connection. The electrode used is NS 9050. The results of the welds are reviewed from the tests carried out, including Radiography Test, Macro Test, and Hardness Test. The results of the analysis showed that the three variasic welds with porosity defects and incomplete penetration. The width of the HAZ is the largest welded basil with a variation of the Heat input which is 1314,401 J / mm. The value of HAZ hardness variation of 1244.239 J/mm variation has the highest hardness value, and variation 1213.401 J / mm has the lowest hardness