Class 5 Boiler Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

The statement that backing is the use of material placed behind a joint to support molten weld metal is indeed true. In welding processes, backing plays a critical role in ensuring that the molten weld pool has adequate support, which helps maintain the integrity of the weld joint. This support is particularly important in applications where penetration is necessary, and a backing bar or strip can assist in achieving the desired weld profile.

Using backing material can prevent issues such as burn-through or excessive penetration, thereby leading to a more reliable and stronger weld. This technique is often used in conjunction with certain welding methods and on various materials to enhance the overall quality of the weld.

Other options imply limitations or misconceptions about the use of backing. For instance, stating that backing is only necessary for non-pressure applications overlooks the breadth of its usage in pressure applications, where a strong and carefully structured weld is essential. Similarly, the idea that backing is only for cosmetic welding disregards its fundamental role in actual structural integrity and safety in welded joints.