CF8M - A351 vs A743
CF8M - A351 vs A743
(OP)
Hi All,
I've been supplied a casting for which the material certificate states that it is A743 CF8M but for my purposes I require A351. The foundry's wishes to send to me an revised certificate but I'm concerned that the standards are not equivalent to each other. I've only a copy of A351 and I'm not a metallurgical engineer so I'm wondering what are the differences between it and the A743 standard with regards to CF8M? If the standards are in fact different I'll need to convey to the foundry the exact reasons why they'll have to recast the piece in order that they're readily willing to do so.
Any and all expert comments and replies are gratefully received.
Thanks for your time and assistance,
Howie
I've been supplied a casting for which the material certificate states that it is A743 CF8M but for my purposes I require A351. The foundry's wishes to send to me an revised certificate but I'm concerned that the standards are not equivalent to each other. I've only a copy of A351 and I'm not a metallurgical engineer so I'm wondering what are the differences between it and the A743 standard with regards to CF8M? If the standards are in fact different I'll need to convey to the foundry the exact reasons why they'll have to recast the piece in order that they're readily willing to do so.
Any and all expert comments and replies are gratefully received.
Thanks for your time and assistance,
Howie





RE: CF8M - A351 vs A743
The basic difference between these two material specifications is that A 351 is for pressure-retaining service, while A 743 is for general application, in corrosive service.
What could happen, and I have seen this before, is to have dual certification for the same grade of cast material. What this means is that a particular grade of material is supplied where the chemical composition, mechanical properties and inspection/tests are met for both material specifications.
If dual certification is not possible, I would go back and reject the A 743 due to the fact that it is not intended for pressure-retainig service under Scope.
RE: CF8M - A351 vs A743
However,having been involved in manufacturing of castings for a long time, it would be very harsh on the manufacturer to reject them before giving another opportunity.
If test samples are still available,you may conduct independent analysis or draw samples from castings. Also,if they are pressure parts like a valve body,perhaps you may check for radiography or leak test,before accepting them. This would ensure,that you get a product, conforming to your requirements.
Costs you can charge to the vendor. Hope,this helps.
RE: CF8M - A351 vs A743
RE: CF8M - A351 vs A743
RE: CF8M - A351 vs A743
RE: CF8M - A351 vs A743
What more are you looking for? The responses above have indicated going the route of dual certification based on comparison between the two material specification requirements. There are various ASTM material specifications that are generated based on Purchaser/Vendor need and specific service application, there is no one size fits all.
My apologies, but you have missed the boat, if all you can conclude from the above responses is "I'd like to think that the difference between a pressure retaining part and one for general corrosive service is more than semantics and a change to the standard's title and its number".
RE: CF8M - A351 vs A743
I agree with metengr, and would like to offer the constructive advice that if you feel the responses are lacking, which they are not, then it costs $39.00 to obtain ASTM A 743 directly from ASTM. My guess is that $39 is a paltry amount compared to the cost of your project.
RE: CF8M - A351 vs A743
The foundry's metallurgical engineer didn't know this either until I sat down with his copies of the standards, went through them myself, and then explained it to him. Seems to me that anyone who offers comments regarding a standard, much less a casting to that standard, should be well versed in said standard.
RE: CF8M - A351 vs A743
We all agree with that last statement. Very frustrating.
RE: CF8M - A351 vs A743
I would suggest that the end user may be able to accept a product . He would also have an understanding of legal implications in the use of the product. He may be able to "sign off" on some discrepencies.