Titanium castings repair welding defect type

The defects on the surface and inside of the casting can be eliminated by repair welding, and the technical conditions of the general product allow 1 to 2 times of repair welding, and the inspection is required to be carried out in accordance with the original X-ray detection process after repair welding.

After the casting is repaired, new defects may appear in the welding area. The evaluation of welding defects in the repair welding area should be carried out in accordance with the relevant technical documents, or by referring to the X-ray inspection standards for welded joints. There are mainly the following types of defects in the welding area of castings.

(1) Common welding defects: cracks, non-fusion between layers, pores, inclusions, tungsten, etc.;

(2) Residual casting defects: casting defects are not completely removed, not completely eliminated, and there are original defects such as shrinkage holes left at the edge of the repair welding area;

(3) Boundary defects: When the thickness of the casting is large, the repair welding area is small and the depth is large, if the welding process is improper, an unfused defect will be formed at the edge of the repair welding area.

It is worth noting that in the case of smooth grinding of the workpiece surface, even if there is no defect in the welding area, the blackness of the area is significantly different from the blackness of the casting area, and in most cases the blackness is less than the surrounding area. The main reason for the difference in blackness between the repair welding area and the casting area is that the composition and organization of the repair welding area and the casting area of the workpiece are different, which causes the change of the ray absorption coefficient, so it can not be simply judged as the defect of the repair welding area. Figure 2 shows the X-ray inspection film of the welding defect of large casting made of ZTA15 material, with a wall thickness of 8 mm. After the welding, the surface of the workpiece was polished and smooth for X-ray reinspection. The blackness of the welding area was significantly lower than that of the surrounding area, and the image features of the welding defect were the same as those of the welded joint.