Ways to avoid welding cracks in large-size cemented carbide-3

       

4 　Process control in finishing

If the finishing method is improperly used, it will produce processing stress and also cause alloy processing cracks. Therefore, we must pay attention to it. Therefore, the following process control is carried out.

(1) Machining with a small multi-purpose grinder can reduce the grinding force and reduce the grinding stress;

(2) Before welding, rough grinding the alloy thickness, outer circle and angle, and strictly control the margin, leaving a unilateral margin of 0 1 4 ～0 15mm on the outer circle, and a unilateral margin of 0 1 10 ～ 0 on the end face. 1 15mm to reduce finishing allowance;

(3) After welding, it is divided into rough and fine grinding, and after rough grinding, it is placed for one day before finishing to release the welding stress and grinding stress step by step;

(4) Strictly control the grinding feed rate ≤ 0 1 02mm, smooth grinding ≥ 2 times;

(5) Add water for cooling during grinding, and the cooling should be sufficient, not intermittently, to avoid the generation of alternating stress between cold and heat.

 5 Conclusion

By reducing the brazing temperature, preheating before welding, slow cooling after welding, selecting brazing filler metals with better plasticity, adding compensating copper sheets, and improving the welding joint form, the reliability of welding will be greatly improved. But you must pay attention to three details, which are often overlooked. One is to clean the surface before welding, remove oxides, etc., and to dry the workpiece to be welded; the other is to pay attention to the difference between the induction coil and the workpiece to be welded during welding. For the relative position, in principle, the welded part should be placed in the middle of the induction loop to ensure the uniform and rapid heating process. The workpiece is positioned with non-steel parts to ensure the stability of the position; third, the solder cannot form a closed loop, avoiding its own induction The electric current heats up and melts prematurely.