ER410 overlaying 1 1/4 chrome turbine governor valve seats

Date 02-15-2011 18:26

If the metal is clean, base and wire (primarily concerned with the wire surface), and you have proper shielding, and all gas connections are good, porosity should be virtually non existent. All of our orbital work, wiggly narrow gap or straight up, gets trailing shields. We generally use customer supplied wire, which for the most part has been very good, but I'd look to Arcos or Special Metals for wire based on personal experience with their wire cleanliness.

As for the buffer, it'd be a metallurgical issue. Shouldn't really make much of a difference to the process.

Is this hot wire or cold wire? Just curious.

By mnelson (*)

Date 02-16-2011 13:20

Cold wire, we have run a coupon dulicating the welding process with the same equipment set up, machined the coupon with no porosity or pin hole issues.

Our suspicion is trash in the base metal. This steam chest is 60+ years old.

We also added 100% argon backing to the cavity.

After two ER309 base metal weld passes, weld quality is vastly improved. The first two ER309 weld passes were flat topped.

Currently have two ER410 overlays in and looking good

We did get the blessings of our Metalugical people to use the ER309 on a limited basis (2 passes max)

Whatever the 309 does, it seems to be working

We did get acceptable welding on three other GV seats, two are problematic.

Thanks gentlemen

By RonG

Date 02-15-2011 19:49

We generally use INCO 82 for that purpose but 309L should work as well (I'm guessing you premachined for the inlay and are useing GTAW). INCO Works well for Stellite seats & stems also.

By MBSims

Date 02-17-2011 04:17

You really don't want to use 309 in this application. Most of these turbine governor valves run at 950-1000 degrees F in a fossil plant. The difference in thermal expansion will eventually cause cracking along the fusion line in the 1 1/4 Cr. A buffer layer of ER80S-B2 weld metal would be best if you are just wanting something clean to apply the 410 onto instead of the casting.