For a 44 mm thick plate, the minimum preheat distance from the weld per CSA W59 is at least how many millimeters?

For a 44 mm thick plate, the minimum preheat distance from the weld per CSA W59 is at least how many millimeters?

• A. 50 mm
• B. 25 mm
• C. 75 mm
• D. 100 mm

Answer: (C)

When welding thick steel, the standard sets a minimum distance from the joint that must be preheated to help slow cooling and reduce hydrogen-related cracking in the heat-affected zone. The farther the heat has to spread around the weld, the larger this minimum distance must be. For a plate that is 44 mm thick, CSA W59 specifies that the minimum preheat distance from the weld is 75 mm. This means the preheating must extend at least 75 mm away from the weld to meet the requirement. Distances smaller than 75 mm don’t meet the standard for this thickness, while a distance like 100 mm is permissible but exceeds the minimum.

When welding thick steel, the standard sets a minimum distance from the joint that must be preheated to help slow cooling and reduce hydrogen-related cracking in the heat-affected zone. The farther the heat has to spread around the weld, the larger this minimum distance must be. For a plate that is 44 mm thick, CSA W59 specifies that the minimum preheat distance from the weld is 75 mm. This means the preheating must extend at least 75 mm away from the weld to meet the requirement. Distances smaller than 75 mm don’t meet the standard for this thickness, while a distance like 100 mm is permissible but exceeds the minimum.