Is it compliant to certify A 193 B7 material as A 194 2H nuts? 3

[vanmorrison]

Upon recept inspection of nuts specified as A 194 2H nuts in a purchase order the vendor has certifed A 194 2H nuts when the starting material is A 193 B7. The nuts were procured from a material organization.
The starting material as per the per material traceability heat # and accompanying CMTR with the material is A 193 B7.
The CMTR supplied meets the chemical percentage requirements of A 194 2H with the exception of additional elements of Cr and Mo as specified for 193 B7.
A 194 2H specifies conformance to A 962 is required. It states that the starting material shall not contain an unspecified element other than nitrogen in austentic stainless steels for the ordered grade to the extent that it then conforms to the requirements of another grade for which that element is a specified element having a minimum content.
I believe this is the situation with the material received and therefor in nonconformance to the material specification, purchase order and design requirements.
In addition the differences between heat treatment requirements between the 2 materials specification I do not fully comprehend as acceptable either.
I am shopping my concern around so that I can either put my concern to rest or for validity before I raise the issue as a material and vendor noncompliance. If concerns with compliance is valid the issue may require Regulatory involvement. The nuts are being used on a high pressure turbine. Any information or comments are welcomed.

 

[rcchap]

I would tend to agree with your assessment.

A193 B7 is a bolt specification. This is a different material than A194 2H. I am not sure why the manufacturer would make nuts out of a bolt material. I have never seen a dual material certification for B7 and 2H.

It could be a mistake on the CMTR. Before you raise the flag, it might be worth it to give the supplier a call to make sure you have all the information.

 

[vpl]

I agree with your assessment. At best you have a paperwork issue because the CMTR does not conform with the requirement. At worst, the nuts don't conform with the purchase order.

It might be possible for the nuts to be used, but that would require an engineering evaluation of the non-conforming part.

Raise the flag on this. I recommend writing a corrective action document (whatever your organization calls it.) Then any actions to resolve the non-conformance, such as calling the supplier, can be properly tracked to ensure traceability.

Patricia Lougheed

******

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.

 

[vanmorrison]

Thank you for your responses.

 

[QAFitz]

While i agree there is an issue, I've had Engineers indicate that starting material is starting material and then ask me would it be an issue if there was only the chemistry listed on the starting material certification (no reference to a specification like A193 or A434)? You look for the required attributes (chemistry, minimum tempering temp etc.) and do whatever is necessary to make that starting material meet the finished material Standard.
Think about the starting material for an A193 Gr. B8 fastener which could be A276 Type 304 or A479 Type 304. Would these be an issue? Now, what if these same starting materials were then used for an A194 Gr. 8 nut?
Just a thought.

 

[vanmorrison]

The thread lives...yah!

QAFtiz thanks for your comments. I look forward to wraping my head around the specs and the concept noted in your post...tomorrow. I do understand that some starting material specs could cover a # of different final specs and that some prohibit "unspecified" elements so that it conforms to another grade.

 

[trottiey]

There's a lot more to a material than just an element soup. For example, the SA-194 nut specification says they must be made from hot wrought bar. SA-193 austenitic bolts must receive carbide solution treatment. Both specifications require UN or metric threads. You could have exactly the same chemistry and heat treatment, but if it has a British Whitworth thread, or is not threaded, then it's a different material.

A material organization with the right certificates could take a hot-rolled bar with the right chemistry and paper trail and make an A194 2H nut out of it. That same bar might also be used for the bolt. But once you've cut the thread and given it the carbide solution treatment, then it's not hot-rolled bar anymore. You can't go back and use your A193 bolt as a starting material for the nut unless you fully remelt it and start from scratch. I don't think you could even use A276 bar, because that specification doesn't include a hot-rolled condition.

 

[gmax137]

And I thought I was the only one here who cared about Whitworth fasteners