CA 6Nm Castings

[arunmrao]

This alloy is used extensively in hydroelectic machines like runner blades, turbine wheels, nozzles etc. I have not come across any discussion on these. Are they not any more current or have they been replaced by some other alloy.

I have not been producing these castings for the past 5 years. Normally for spares, coordinating with the government bodies is a hassle hence I am out. But there is a big business I am sure.

 

[bruv]

We occasionally cast the stuff to the ASTM standard. Recently we have produced a variation with an increased carbon level for a particular customer requirement. The end product is a large valve trim component.

Our biggest problem arose when we did an ASME IX weld procedure, with NACE hrdness requirements. It took a lot of time trying to get the hrdness below the NACE limits, and we ended up with some very long heat treatment times.

Bruv

 

[arunmrao]

bruv, what was the hardness you were aiming at? Normally I used to get 220 BHn after a prolonged double tempering cycle. Carbon used to be 0.03-0.04%

 

[bruv]

With the long temper times, we were looking for 24HRc maximum.

Bruv