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On-site metallography solves a pressure vessel problem

 
Electropolishing: a final stage of preparation for on-site metallography
Electropolishing: a final stage of preparation for on-site metallography

An Industrial Member contacted TWI for advice on remedial heat treatment of welded strakes used in the construction of a pressure vessel. The hot-formed strakes had been welded before normalising could be carried out and the company was rightly worried about the effect of a remedial heat treatment on the strength of the weld metal.

The company's initial thought was that the weld metal would have to be removed before heat treatment and the strakes rewelded afterwards. This could even have meant starting again with new strakes.

TWI was able to resolve the problem however, by performing an on-site metallographic examination of the strakes and carrying out laboratory tests. Results showed the microstructures and properties of the strakes to be perfectly acceptable, even though a normalising treatment had not taken place after hot forming. It was found that the strakes could be used as formed, thus saving the cost of re-welding or starting again.

 

For more information please email:


contactus@twi.co.uk