What is the maximum permitted surface roughness when thermal cutting a groove face prior to groove welding?

The maximum permitted surface roughness when thermal cutting a groove face prior to groove welding is 1000 microinches. This standard is set to ensure proper bonding and penetration of the weld metal into the base metal. A smoother surface facilitates better fusion, reducing the likelihood of defects such as porosity and incomplete fusion that can compromise the integrity of the weld.

In welding practice, maintaining the specified surface roughness helps in achieving a quality weld that meets structural and safety requirements. While other surface roughness values may exist for different processes or materials, 1000 microinches is the threshold for thermal cutting processes in groove welding, ensuring that weld quality is not adversely affected.

The other options, although they represent varying levels of surface roughness, either exceed or do not meet the optimal conditions necessary for effective welding in this context, which is why they are not suitable.