The casting defects of coupler tongue include crack, sand inclusion, mechanical sand sticking and other defects.
In the actual trial production, the crack defects of the hook tongue mainly include the root of the gate, the middle and upper part of the inner wrist surface, the opening part of the hook tongue, the upper part of the guard pin flange, etc. Figure 1 shows the test production parts after flaw detection and crack welding repair. The crack defects of the knuckle are mainly thermal cracks, and the cracks (b) (c) (d) in Figure 1 should be thermal cracks. Cold cracks mainly appear at the gate root or welding position.
(b) Sand is mixed around the pin hole of coupler wrist head
The sand inclusion defect of the hook tongue mainly occurs at the platform around the upper surface of the hook tongue pin hole and the hook wrist head pin hole, as shown in Figure 2. This sand inclusion needs to be cleaned, but it does not need to be repaired by welding.
Mechanical sand sticking defects mainly appear on the inner wrist surface of the hook tongue. The surface of the sand core at the inner wrist surface finally forms mechanical sand sticking under the strong thermal action of the liquid steel. Figure 3 shows the situation after the mechanical sand sticking is cleaned, and the surface is rough.