Impact values on Hastelloy C276 cast steel CW12MW

[marcolino21576]

Dear All,

we have produced one sand cast body acc. ASTM A494 CW12MW (corrispondent of Hastelloy C276); it's a pressure containing part, therefore customer requested us to carry out an impact test at T=room (not requested by ASTM A494), guaranteeing 27J minimum.

Now, we have carried out the tests, finding 8% elongation (4% minimum required by ASTM) and impact test 14-12-11J (much lower than additional request of 27J made by customer).

Practically speking, my impression is that a material whose minimum elongation is 4% will hardly be able to achieve an impact value higher than 27J, but I would like your opinion on the matter.

Thank you in advance for your help

BR

Marco

 

[metengr]

My opinion is that we don't know the quality level of the sand castings to make a complete judgement. I do believe you should be able to reach 27J at RT for this alloy. Wrought product form of C-276 listed by Haynes for Charpy U-notch is >200 J at -320 deg F.

I would suspect you have a quality problem with these sand castings. I do agree that your properties will be much lower for the casting form in comparison to wrought product form, but I would believe you should easily reach 27 J at RT.

Look at casting quality and check thermal treatment that was performed for the sand casting.

 

[blacksmith37]

And, tensile ductility has only a very indirect relation to impact toughness.

 

[EdStainless]

Though I'll say that 8% elong is also rather low for this grade. I would expect something like 15%, the wrought grade is usually over 45%.
Have these been solution annealed?

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Plymouth Tube

 

[arunmrao]

The solutionising cycle,which needs a high temperature of soaking (1180-1200C) and water quenching must be missing. Also there could be an issue with the quality of test bar. It is a tough call to produce a Hastealloy valve body casting. I have been there and struggled producing an acceptable quality.

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"The richer we have become materially, the poorer we have become morally and spiritually." Martin Luther King Jr

 

[marcolino21576]

Thank you very much to everybody for your help.
We will keep investigating.

Marco