Pengaruh Perlakuan Panas Terhadap Sifat Fisis, Mekanis Dan Korosi Pada Pengelasan Baja Tahan Karat Austenit AISI 304

Hengki Front Viryawan, Prof. M. Noer Ilman, ST., M.Sc., Ph.D.

2007 | Skripsi | S1 TEKNIK MESIN

Penggunaan teknologi las saat ini sangat luas dan terus berkembang scsuai pertumbuhan industri di seluruh dunia. Salah satu metode pengelasan yang banyak dipakai saat ini adalah las busur listrik elektroda terbungkus (shielded metal arc welding-SMAW). Pengelasan inijuga sesuai digunakan untuk mengelas baja lahan karat (sta.inless sleel). Soringkali hasil pengclasan suatu konstruksi diaplikasikan pada lingkungan yang bertemp€ratur tinggi dan bervariasi. Tujuan dari penelitian ini adalah untuk menganalisa pengaruh variasi perlakuan panas setelah pengelasan (postweld heat treatment-PwHT) pada pengelasan baja tahan karat austenit seri 304 dcngan tipc elektroda E 312. Analisa yang dilakukan meliputi struktur makro dan miko, kekerasan, dan ketahanan korosinya. PWHT yang digunakan ada tiga variasi, yaitu tanpa pcrlakuan panas, dcngan unnealing, dan dengan quenching. Dengan annealing yaitu hasil lasan dipanaskan pada tempcratur 600 'C, ditahan 6 jam dan didinginkan di dapur. Dengan quenching yaitu hasil lasan dipanaskan pada temperatur 1050 "C, ditahan I jam dan dicelup kc dalam air. Pcngujian korosi dilakukan dcngan dua cara yaitu dengan memakai afat Potensiostat dengan media korosif larutan 3o/o FeClt dan dengan merendam benda uji dalam larutan 6Yo FeCb.

The use of welding technology is currently widespread and continues to evolve in line with industrial growth worldwide. One welding method widely used today is shielded metal arc welding (SMAW). This welding method is also suitable for welding stainless steel. Welding results in construction are often applied in high and variable temperature environments. The purpose of this study was to analyze the effect of postweld heat treatment (PWHT) variations on welding 304 series austenitic stainless steel using type E 312 electrodes. The analysis included macro and microstructure, hardness, and corrosion resistance. Three variations of PWHT were used: untreated, unnealed, and quenched. With annealing, the weld is heated to 600°C, held for 6 hours, and cooled in a furnace. Quenching involves heating the weld to 1050°C, holding it for 1 hour, and then immersing it in water. Corrosion testing is performed in two ways: using a potentiostat with a corrosive medium of 30% FeCl2 solution and immersing the test specimen in a 6% FeCl2 solution. Microstructure tests revealed that without heat treatment and annealing, the grains become smaller, making them susceptible to corrosion and increasing hardness due to the formation of numerous carbide precipitates. This carbide is corrosive. With quenching, the grains appear larger, decreasing corrosion resistance and hardness. These results are comparable to those obtained from microhardness and corrosion tests. The research concluded that PWT welds have advantages and disadvantages. Therefore, when applied to an environment with a temperature of 600°C for a period of time and the environment cools slowly, corrosion resistance decreases but hardness increases. Furthermore, when applied to an environment with a high temperature (1050°C) and then to a higher temperature (1050°C),

Kata Kunci : Pengaruh, Perlakuan Panas, Sifat Fisis, Sifat Mekanis, Korosi, Pengelasan, Baja Tahan Karat, Austenit AISI 304