Influence of Heat Treatment on the Mechanical Properties in Various Weld Zone of the Structural Alloy Steel

구조용(構造用) 합금강(合金鋼) 용접(熔接) 각부위(各部位)의 열처리(熱處理)에 따른 기계적(機械的) 성질(性質) 변화(變化)에 관(関)한 실험적(實驗的) 연구(硏究)

To investigate the influence of annealing heat treatment on the mechanical properties at the various weld zone, an experimental study was performed for the structural alloy steel. The results obtained from the experimental works are as follows: 1. Hardness and tensile strength showed the highest value at the heat affected zone, which was 5mm apart from bond zone. With increasing of annealing temperature, hardness and tensile strength were decreased at every weld zone, and bound in heat affected zone was increased. 2. Impact strength was the highest at the filler metal, and increased with increment of annealing temperature at filler metal and base metal. However, both at bond and heat affected zones, impact strength was increased from $700^{\circ}C$ of annealing temperature, and was decreased again over $900^{\circ}C$. 3. Mutual relationship between the mechanical properties at filler and base metals showed a similar linearty to that the common structural steel did. However, it varied unsteadly both at bond and heat affected zones. 4. It may be concluded that proper annealing temperature is $700^{\circ}C$ from the viewpoint of hardness, tensile and impact strength.