PENGARUH VARIASI ARUS PADA PROSES PENGELASAN SMAW UNTUK MATERIAL BAJA ST 37 TERHADAP KEKUATAN IMPAK DAN KEKUATAN TARIK

THE EFFECT OF CURRENT VARIATIONS IN THE SMAW WELDING PROCESS FOR ST 37 STEEL MATERIAL ON IMPACT STRENGTH AND TENSILE STRENGTH

Baja karbon rendah dengan tipe ST 37 merupakan jenis logam yang memiliki kandungan karbon yang rendah. Baja ST 37 termasuk baja karbon rendah, karena memiliki sedikit kandungan karbon tidak sampai 0.3%. Adapun kandungan lainnya seperti Mangan (Mg) 0.8%, nikel (Ni) 0.1%, sulfur (S) 0.05%, dan beberapa mineral lain. Baja ST 37 sering digunakan dalam industri otomotif, terutama pada salah satu bagian rangka sepeda motor yaitu Swing Arm. Bentuk Swing Arm mengikuti jenis suspensi, salah satunya Swing Arm tipe Prolink. Pada proses pengelasan dudukan (Mounting) Swing Arm tipe Prolink harus diperhatikan agar menghindari terjadinya cacat las atau deformasi yang berdampak pada sifat mekanik material agar dudukan  (mounting) Swing arm tipe prolink tidak patah.

Pada Penelitian ini dilakukan dengan metode eksperimen yang menggunakan variasi arus pengelasan dengan jenis pengelasan SMAW pada material baja ST 37. Kemudian variabel tersebut diuji kekuatan impak dan kekuatan tarik. Lalu dianalisa pengaruh dari variabel bebas terhadap variabel terikat. Dalam penilitian ini, variabel bebas terdiri atas variasi arus pengelasan 105 A, 115 A, 125 A.

                Hasil penelitian menunjukkan pengaruh variasi arus pada proses pengelasan SMAW terhadap uji impak dan uji tarik. Pada pengujian kekuatan impak, variasi arus pengelasan 105 A menghasilkan nilai rata – rata terbaik dengan nilai 0.168 J/mm². Pada pengujian kekuatan tarik, variasi arus pengelasan 125 A menghasilkan nilai rata – rata tegangan tarik maksimal terbaik dengan nilai 382.51 Mpa.

Kata kunci : Baja ST 37, Swing Arm tipe Prolink, Las SMAW, Arus Pengelasan, Uji Kekuatan Impak dan Kekuatan Tarik.

ST 37 low-carbon steel is a type of steel with a relatively low carbon content. ST37 steel is classified as a low-carbon steel because it contains less than 0.3% carbon. It also contains other alloying elements, including 0.8% manganese (Mn), 0.1% nickel (Ni), 0.05% sulfur (S), and several other trace elements. ST37 steel is widely used in the automotive industry, particularly in motorcycle frame components such as the swing arm. The design of a swing arm depends on the suspension system, one of which is the Pro-Link type swing arm. During the welding process of the mounting bracket on a Pro-Link swing arm, proper welding procedures must be applied to prevent welding defects or deformation that may adversely affect the mechanical properties of the material and lead to failure of the mounting bracket.

This study employed an experimental method by applying different welding current variations in the Shielded Metal Arc Welding (SMAW) process using ST37 steel as the base material. The welded specimens were subsequently subjected to impact and tensile strength tests. The effects of the independent variable on the dependent variables were then analyzed. The independent variable in this study consisted of welding current variations of 105 A, 115 A, and 125 A.

The results showed that welding current variations in the SMAW process affected both the impact and tensile strength test results. In the impact strength test, the welding current of 105 A produced the highest average impact strength, with a value of 0.168 J/mm². In the tensile strength test, the welding current of 125 A produced the highest average ultimate tensile strength, with a value of 382.51 MPa.

Keywords : ST 37 Steel, Pro-Link Type Swing Arm, Shielded Metal Arc Welding (SMAW), Welding Current, Impact Strength Test, Tensile Strength Test.