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[MW:29148] Welding Invar 36

By Materials & Welding

Dear All,

 

Recently, we faced a problem welding INVAR-36/Alloy 36 (Ni 36%, Fe – 62%)  diaphragms used in gas turbines, which is block of 2 inch thickness approximately.

 

This is actually not a weld to weld joint, but only a material built up for building up thickness. Based on our experience we have found Nimonic 263 filler wire using TIG works well for material build up on INVAR-36 diaphragms.

 

Currently, we have a situation while welding with Nimonic 263, spattering occurs during welding. In fact, welding and melting is not taking place at all. Only spatters are observed, with some black color localized oxidation. We then tried using different filler wires such as SS308, IN-625 but the spatter and non-melting problem continued. We then tried with ERW method using Ni-Rod electrode and it worked to some extent, but lot of porosity was observed.

 

We are now thinking of using Alloy 36 filler wire, but not sure whether the problem will be eliminated.

 

Please let me know if anyone has any experience with a similar kind of problem, welding INVAR-36/Alloy 36 material.

 

 

 

Regards,

 

Girish Shejale

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