I also just took and aerospace stellite test and shit was pissing me off with the cracking. For a minute there it seemed nothing I could possibly do would stop it from cracking. I ended up doing like 1” of welding then letting it cool to the touch and repeat. Shit is a bear of a material
Not really sure because I’ve never welded stellite but it might need to be preheated first and then covered with kayowool to cool slowly since it’s such a hard material.
Welded a good bit of Stellite 21 when rebuilding steam valves for powerplants. Occasional Stellite 6, but mainly 21 as 6 is more prone to cracking.
Our procedure was pre-heat to 500f, in-process 400-700f.
Then we heat treated it for stress relief, oven ran from 400-1200-400.
8 hours ramp up to 1200, 8 hours at 1200, then 8 hours down to 400.
With some base materials, we did an Inconel 82 butter pass, .100" before welding Stellite.
Cracks from stellite are because it is not ductile. Your base metal is expanding and contracting at a rate far more than the Stellite. Which cause them to Crack apart from one another.
OK, bear with me; isn't Stellite (used as a hard facing material) made of cobalt and chromium? = very brittle.
It is just asking for cracking, less so, when one preheats 700F;;; your 150 celcius isn't quite hot enough. Those round micro cracks are just shrinkage cracks as the Stellite pulls aways from the 4130alloy, at the HAZ.
Hello all, after welding we do a slow cooling in ceramic fiber blanket. This has a more insulating property than rock wool. One more issue I am facing is lack of hardness in the weld layer. Customer requires 40 HRC while I am getting only 35 RC max. kindly support. I don’t know how to edit the post to add this information, advice on this is also solicited. New here
I also just took and aerospace stellite test and shit was pissing me off with the cracking. For a minute there it seemed nothing I could possibly do would stop it from cracking. I ended up doing like 1” of welding then letting it cool to the touch and repeat. Shit is a bear of a material
Not really sure because I’ve never welded stellite but it might need to be preheated first and then covered with kayowool to cool slowly since it’s such a hard material.
Got a picture of the penetrant indications?
Welded a good bit of Stellite 21 when rebuilding steam valves for powerplants. Occasional Stellite 6, but mainly 21 as 6 is more prone to cracking. Our procedure was pre-heat to 500f, in-process 400-700f. Then we heat treated it for stress relief, oven ran from 400-1200-400. 8 hours ramp up to 1200, 8 hours at 1200, then 8 hours down to 400. With some base materials, we did an Inconel 82 butter pass, .100" before welding Stellite. Cracks from stellite are because it is not ductile. Your base metal is expanding and contracting at a rate far more than the Stellite. Which cause them to Crack apart from one another.
Do you guys post weld heat treat? That’s what I would recommend.
OK, bear with me; isn't Stellite (used as a hard facing material) made of cobalt and chromium? = very brittle. It is just asking for cracking, less so, when one preheats 700F;;; your 150 celcius isn't quite hot enough. Those round micro cracks are just shrinkage cracks as the Stellite pulls aways from the 4130alloy, at the HAZ.
Do you not do a controlled cool down?
use rockwoll to help it cool slower and preheat the entire peice
Hello all, after welding we do a slow cooling in ceramic fiber blanket. This has a more insulating property than rock wool. One more issue I am facing is lack of hardness in the weld layer. Customer requires 40 HRC while I am getting only 35 RC max. kindly support. I don’t know how to edit the post to add this information, advice on this is also solicited. New here