Alloy Designation Needed

[SMF1964]

Ferrous alloy, 0.23Carbon, 1.35 Cr, 0.49 Mo, 0.2 V, 0.66 Si, 0.56 Mn.

It essentially looks like 1¼Cr-½Mo-¼V, but I cannot find a US alloy that fits that designation. Is there a european alloy? The material is a pipe used for a long-retract lance/sootblower and used to be made by Copes-Vulcan, but I am told it is no longer.

 

[metengr]

The closet alloy match that I could find for the Cr-Mo-V steel you described for your sootblower lance is an SCM420 steel. The following is a supplier that can provide tubing in this grade;

http://www.ismtna.com/products/steelsupply.html

 

[metengr]

I just noticed that this tubing grade doesn't contain V - my error on the V. We have numerous sootblower lances that are supplied as T22 tube material versus the modified T11 with V. I see no reason for your sootblower lance material to be any different. The V is added to improve elevated temperature strength, meaning you could get by with a thinner tube wall. If you really want to maintain a thinner tube wall you could upgrade the lance material to T91 or even T23 tube material, which is available.

Our sootblowers use either air or steam and we have had no serious maintenance or operational problems with the T22 material -as long as the lance does not get stuck in the boiler.

 

[SMF1964]

There is a stainless steel 'head' welded on the end of these. Have you had issues with failure at the welds in your sootblowers?

 

[metengr]

No, not yet. We had installed several sootblower lances with the stainless steel spray head several years ago at one of our generating sites. I am not sure who sold us the modified lances. The spray head was designed to improve the spray arc pattern and cleaning efficiency for boiler tubes.

The stainless steel heads should be attached to the lance with Inconel versus 309 filler metal. I do remember that we had requested the Inconel filler metal because we were concerned about thermal stresses from differential expansion and carbon migration.