What is required on the exposed surfaces of each nick break?

The requirement for complete penetration and fusion on the exposed surfaces of each nick break is essential for ensuring the integrity and strength of a welded joint. Complete penetration means that the weld metal has fully penetrated the base materials and fused with them, creating a joint that can withstand applied loads without failure. This is particularly significant in pipeline welding, where the potential for leaks or breakages can have serious safety and environmental consequences.

The presence of sound weld metal across the joint, characterized by complete penetration and fusion, guarantees that the weld has achieved the necessary mechanical properties. Such properties are vital for the structural integrity of pipelines, especially when they are under pressure or subjected to various stresses during operation.

Additionally, this requirement ensures that there are no voids or inadequate bonding at the joint, which could lead to weaknesses. The requirement for complete fusion helps inspectors and engineers verify that welding procedures were followed correctly and that the resulting weld will perform as expected under service conditions.