4 Welding operation outline
4.1 Welding Symbol: Omission
4.2 Design notes on welded joint: Omission
4.3 Welding Process
4.3.1 Preparation before welding operation
"Weld Dryer" prevents deterioration of welding rod and improves welding quality
- Welding quality deterioration due to moisture absorption of welding rod
- Arc discharge defect
- Increase in spatter
- Causes of blowholes and pits
- Decrease in weld strength
4.3.2 Preventing quality deterioration due to moisture absorption of welding rod
- Quality preservation by welding rod containing element
Note: Consume within the specified time- Low hydrogen type welding rod
- Keeping temperature: 300 [^{\circ}C] or more 400 [^{\circ}C] or less
- Heat retention time: 1 [h] or more 2 [h]
- Other welding rod
- Keeping temperature: 80 [^{\circ}C] or more 150 [^{\circ}C] or less
- Heat retention time: 0.5 [h] or more 1 [h]
4.3.3 Welding using jig: Omission
4.3.4 Tack welding
Precure carefully for welding in metal plate thickness, low alloy steel, cold district
4.3.5 Welding condition: Omission
4.3.6 Main welding
- Types of beads in the welding theory
- Line: Stringer bead
- Width expansion: Waving bead: Easy trigger of slag
4.4 Change due to metal welding and acceptance stress
4.4.1 Method for preventing deformation of metal welding
- Restraint method
Suppression of distortion between bonding metals by using restraint jig
- Inverse distortion method
Weld metal by anticipating the direction after metal welding and deforming it in the opposite direction
- Change welding direction
Prevent shrinkage distortion between joints by changing welding direction- Backstep method: welding to an obtuse welding rod
- Flight method: welding to sharp corner welding rod
- Symmetrical method: welding from the center to the end
4.5 Change due to metal welding and acceptance stress
- Weld defect and measures
- Lack of surplus
- Surplus excess
- Lack of leg length
- Accepted shape: proper surplus
最終更新：2018年12月14日 05:04
