Topic: Manufacturing Processes
Pre-heating before welding is done to
- A. Make the steel softer
- B. Burn away oil, grease, etc. from the plate surface
- C. Prevent cold cracks
- D. Prevent plate distortion
Answer: C. Prevent cold cracks
Explanation: Pre-heating the material prior to welding serves to slow down the cooling rate in both the weld metal and the heat-affected zone. This controlled cooling greatly minimizes thermal stresses and effectively prevents the formation of cold cracks and scratches in the joint.