Certified Welding Inspector Practice Exam

What does arc spraying involve?

1. A thermal spraying process using an arc as a heat source

2. Melting metals together without any heat source

3. A process for reducing metal waste in welding

4. A bonding technique that requires curing

The correct answer is: A thermal spraying process using an arc as a heat source

Arc spraying is a thermal spraying process that utilizes an electric arc as the heat source to melt metal wire before it is atomized into fine particles. This is achieved by feeding the metal wire into a pair of electrically charged nozzles where an arc is established. The intense heat from the arc melts the wire, and compressed air or gas then atomizes the molten metal, projecting it onto a prepared surface. This method is commonly used for coating surfaces to improve wear resistance, corrosion protection, and other surface properties. The process allows for the deposits of coatings at a relatively high deposition rate, making it an efficient technique for various industrial applications. In contrast, the other options do not accurately describe the characteristics or processes associated with arc spraying. For example, melting metals together without any heat source doesn't apply to any process used in arc spraying since heat is essential to melt the metal. Similarly, reducing metal waste in welding and bonding techniques that require curing do not pertain to the specific mechanics or aims of arc spraying.