The quality level of the joints after exothermic welding is divided into three types (optimal, acceptable, unacceptable) (visual inspection)

1. Best connection: The connector is bronzed with a smooth, shiny surface and no air holes.

2. Acceptable connection: slightly flawed, but does not affect conductivity.

3. Unacceptable connection: The welded conductor is not completely enclosed in the connector, and a large number of air holes appear on the surface of the connector, extending to the center of the connector.

Inspection items include connector shape, color, surface smoothness and air vent

1. Shape: The welded conductor must be completely wrapped in the connector. The concave surface of the connector shall not be lower than the conductor to be welded, and the convex surface shall not be excessively higher than the conductor to be welded. If the concave surface is too low, it means that too much copper liquid leaks, the welding agent is insufficient, the welded conductor is not properly fixed, and the welded conductor moves during the welding process; if the convex surface is too high, it means that the welding agent is used excessively, and the surface volume is increased. (The connector is still acceptable).

2. Color: Under normal conditions, the connector is bronzed, and occasionally there may be a small amount of silver on the top.

3. Surface: The surface of the connector should be smooth without excessive slag. If the fused slag is exposed and exposed, the connector is unacceptable.

4. Porosity: There should be no penetrating pores in the joint. The reason for the excess pores is that there is dirt, moisture or moisture in the surface of the welded conductor or in the mold. A small amount of air holes appear on the surface of the connector, and the hole depth can be checked with a small diameter wire. This connector is acceptable if the depth does not reach the center of the connector; if the depth extends to the center of the connector, the connector is unacceptable. In addition, there should be no stomata or imperfections in the incision inspection section.

5. Strength: The strength should be equal to or higher than the strength of the non-welded joint (ie, the welded joint should not be broken first when the tensile test is performed).