Optimasi Nilai Ketangguhan dan Bentuk Perpatahan pada Pengelasan Busur Terendam Pipa Spiral Baja Api 5L X-52

Submerged Arc Welding is a welding process used for fabrication of pipes, for example spiral welded pipes. The technique can be operated automatically and has a high reliability in many various welding application. Some factor affecting the strength of weld metals are heat input, current, chemical composition of filler and flux, welding speed and cooling rate.
The purpose of this research is to obtaine microstructure caontaining acicular ferrite which give good impact toughness of the submerged arc welded pipes.
Material Used in this experiment was API 5L X-52 spiral welded steel pipes, Welding was carried out using voltage of 35 volt, welding speed of 13,67 mm/s whereas current was varied, namely 800 Ampere, 825 Ampere, 850 Ampere, 875 Ampere and 900 Ampere. A series of mechanical propertis test were carried out including hardness, tensile test and V-Charpy notch impact toughness test.
The result show that, an increase in weld current increase the amount of acicular ferrite structure. The highest toughness were obtained at the current of 900 Ampere where toughness was 150 joule with transition temperature -10°C, and the dimple fracture have higher toughness than the shard fracture.