Abstract:
Friction Welding is one of methods that becomes increasingly popular in industrial since it has many benefits such as no need for flux in welding, no fume generated, providing good quality welding joint with even surface not porous, taking short time for welding etc. However, because of high heat that is generated during welding at welding joints, it leads to the change of the micro structure of steel at welding joints which directly affects the mechanical properties of work pieces.
The objective of this research was to study characteristics of the micro structure of medium carbon steel (AISI1045) which had been processed by annealing and friction welding. 720 pieces of circular cross-section steel with 10 millimeter diameter, 100 millimeter length were used under the welding condition that the pressure of compression were 20, 30 and 40 bars, compressing times were 2, 3 and 4 seconds, annealing temperature were 790, 850 and 970 degree Celsius, its speed was 1,800 rpm. After the welding was finished, the work pieces were tested for their hardness, tension and elements of micro structure at welding joints.
With the comparison of friction welding of work pieces in normal temperature and annealing of work pieces in different temperature, it was found that tension was higher at normal temperature of work pieces after welding than work pieces with annealing, however, the hardness value of welding joints on work pieces at normal temperature was less than work pieces with annealing. For the micro structure, it was found that steel grain at joints of annealed work pieces was more dedicate than work pieces without annealing which therefore affected to be stronger structure.