Hardness on Inconel 625 casting (A494 - CW6MC)

[SJmetallurgist]

Hello experts.

We have some valves with Inconel 625 material (cast valves with ASTM A494-CW6MC grade material). The valve is machined with RTJ groove. My query is regarding the hardness of this material for RTJ groove specified by the client. Our client specifies that hardness to be minimum 230BHN at RTJ Groove. Whereas the casting is itself received with a hardness of 190 to 200BHN. Even on open source internet literatures I am not able to find any hardness of this range specified for CW6MC material. for more info, must inform that this valve is under NACE MR0175.

Is there a problem with the basis of this hardness specified by the client? is there a problem with my material?
Any avice would be highly appreciated since this is the first time we are dealing with this valve casting material here. Thanks.

Regards

 

[metengr]

I agree. Double check if the hardness should be stated as a maximum value in lieu of a minimum value.

 

[SJmetallurgist]

Well. Surprisinglyuy, the max hardness specified on the ring type gasket of these valves is 200 BHN. So in that sense its not strange to have a hardness of 230BHn min to be asked for the valve RTJ Groove.