Abstract :
At SMAW process, welding position is one of the important parameters
because it affects physical properties which in turn will affect the mechanical
properties of the material. This study aims to investigate the effects of 2G
horizontal, 3G vertical, and 4G overheads position in spiral motion welding SMAW
to the tensile strength and micro structure of ST37 steel.
The treatment used in this research was welding with different welding
positions using SMAW welding with E7016 electrodes and open V seam at an angle
of 60º. Position variations used were 2G horizontal position, 3G vertical position,
and 4G overhead position. The material used was ST37 steel which belongs at low
carbon steel group with less than 0.3% of carbon element. Tensile test and micro
structure test were used at the welding product according to ASTM E8 standards.
The results showed the highest tensile strength obtained from the vertical
3G position variant with average value of 33.08 kgf/mm². Based on the micro
structure test on the welding vertical 3G position, it showed that the acicular ferrite
micro structure dominates the entire area and uniformly locked the grain boundary
ferrite micro structure. Acicular ferrite micro structure is the micro structure
expected from each welding process because the structure is an interlocking
structure that is able to hold the rate of crack propagation. According to the results
of the study it can be concluded that the difference in welding position does not
significantly affect the value of the tensile strength and the formation of the welded
metal microstructure in ST37 steel