How to weld repair a Gear box casting?


Casting repair, a work of patience.

Cast Iron have different types and only some have limited weldability while other are not weldable at all such as white cast iron. Using a correct approach, suitable welding technology, and correct welding electrode, cast iron repair can be mastered.

In this post a detailed step by step welding repair guideline for repairing a Gear box casting is explained.

Click here to Get Guide on How to Weld various materials

Steps to commence the cast iron repair:

1. First of all, drill holes on both sides of the crack to arrest the crack. This will help to eliminate further propagation of the crack into the material.

2. Clean the welding area & surrounding area from any paint, grease or oil contamination.

For welding, I prefer to use the “cold method or also called cold welding” ENiFe-CI SMAW coated stick welding rods. These rod offer a dissimilar weld deposit with high ductility to withstand the high residual stresses arising in cast iron welding.

3. Use very short runs of maximum 30 mm length also called pilgrim welding, no preheat usally but if needed to remove moisture, preheat to maximum 110 Degree Celsius or 225 Degree Fahrenheit.

4. Use hammer peening for residual stress relief after each run. This will help to avoid cracking in the weld.

5. Follow maximum 100 Degree Celsius or 200 Degree Fahrenheit interpass temperature. Alternately, if temperature measuring device is not available, wait until its cold to touch before welding next run.

6. The welding technique will be slow but going to be very fruitful to avoid any cracking in the weld or cast iron HAZ.

7. Dont forget to weld the drilled holes at the end of the welding.

Click here to learn various types of cast iron & their identification.

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