Abstract
The experimental results obtained in case of the manual arc welding process with various type electrodes were summarized. The main factors that have influence upon cooling time near fusion line by welding were determined, and the relations between the main factors and the cooling time were concluded. Thd results of this researchare as follows :
1. On carbon steels and high tensile steels or low alloy steels, the effect of the change of kinds of steels on cooling time from 800°C to 500°C is negligible small.
2. In the case of bead deposited over whole length of a plate, the cooling time is not nearly influenced by the plate length. When the plate width exceed beyond about 150mm, the effect of the width, is also small. The plate of thickness over about 24mm is considered as a plate having infinite thickness, since the cooling time near fusion line of such plate does not change.
3. A certain percentage of the heat generated by welding arc is given in the base plate. The percentage, that is, the thermal efficiency of arc energy is 0.75-0.83 in case of the manual arc welding process with covered electrodas.
4. In case of depositing a long bend on a plate having width over 150mm, the main factors that have influence on the cooling time from 800°C to 500°C near fusion line are type of welding joint, plate thickness, are energy per unit bead length and preheating temperature.
