Technical Step for Repairing Worn Barrel with A Liner

1. Fabricate a piece of blind patch, the shape is the same as the original feeding hole of the barrel. Plug the feeding hole with this blind patch. Please note that the intrados of the blind patch should be conformed to the intrados of the barrel;

2. Grind the hardening layer in the inner hole of the barrel, the thickness of this hardening layer should be around 0.50mm;

3. Enlarge the inner hole of the barrel to Φ170+0.03/0, the straightness should be 0.05mm, roughness is HRa1.6; 

4. Check the size of the inner hole of the barrel, pick up the blind patch from the feeding hole; 

5. Fabricate 3PCs of bimetallic liners for the barrel, the length of the liner is separately 1000mm, 1000mm, 1730mm;

6. Heating: vertically put the barrel in the electric stove, heat up to 600℃ and last 4 hours. Use special length bar measures the diameter of the inner hole, when the diameter is not less than Φ171mm. You need to fabricate the special length bar, its length is 171mm with circular arc-shape in both ends. The length bar is easy to carry and conveniently put it into the inner hole to measure;

7. When you can measure the size Φ171mm of the inner hole, then pick up the barrel immediately, vertically put it in the crypt prepared before. The feeding hole of the barrel should be upturned, the injection end is downward; 

8. Put the 3PCs of liners into the vertical inner hole of the barrel quickly one by one. Firstly the liner with length of 1730mm, then the one with 1000mm length, last the other 1000mm length sleeve;

9. Inspect the inner hole and confirm it is OK, then honing the inner hole of the whole barrel till the size of the inner hole is Φ150+0.03/0； 

10. Turning the both ends of the barrel in the lathe and make the ends smooth; 

11. Fabricate the electrode die head as per the shape of the feeding hole of the barrel, use the electric pulse in the place of original feeding hole to thrust the feeding hole ( Also, you can drill a small hole and enlarge, then finally form a feeding hole.)

This step is just for your reference.