ASME PCC-1 Appendix M

[boofi]

I already saw this thread:

https://www.eng-tips.com/viewthread.cfm?qid=408324

I'm looking for Type 4 washers that meet A829. PCC-1 has the following note:

"(2) Type 4 low-alloy steel washers shall be manufactured from SAE number 4130 or 4140 steel listed in ASTM A829."

However, much like the poor sap above, our vendors for fasteners don't seem to know what PCC-1 is, nor do they have a spec for A829. They are offering 4140HT which does meet the chemistry requirements. I'm trying to figure out a way to determine whether or not we can still use the 4140HT they are offering, after they specifically told me it's NOT A829. What else can I look at? Maybe they can provide the MTRs before they cut the washers?

One caveat is that our washers will be a non-standard thickness; so we've already broken the rules laid out by PCC-1 anyway.

 

[goutam_freelance]

Chat-GPT shows 4140-grade steel is available in A 829. HT may indicate heat treated. Please purchase the standard and check.

Engineers, think what we have done to the environment !

https://www.linkedin.com/in/goutam-das-59743b30/

 

[boofi]

I know it's available in A829, I have the 829 standard. The problem is that the vendor is providing 4140HT and saying it's NOT A829. There are other standards that 4140 is specified to.

 

[GBTorpenhow]

A829 is a spec for plate. The vendor is probably offering washers cut from round bar stock, so they wouldn't be A829. FWIW the way I read the language in PCC-1 the A829 sounds more like a reference for the 4130/4140 material spec than a requirement to use A829.

The HT is some sort of heat treatment designation, which is likely very relevant to your application as the washers want to be hardened to some specific range if I recall PCC-1 App M correctly. The chemistry might be correct as 4140 but the hardness could be out of spec for this HT condition whatever it is. Recommend to get the vendor to state the as delivered hardness and check against what PCC-1 recommends.

 

[boofi]

Thanks GBTorpenhow. I've asked the vendor (or the middleman at least...) to provide hardness, strength, and if possible which spec the 4140 actually is. I suspect you're right, it's probably round bar instead of plate. I'm thinking if the chemistry and the hardness match PCC-1 we should be fine. Not sure about strength requirements though.

Another question though, 829 has a table for Tensile strength ranges. The first column is Specified tensile strength, and the second column is tensile strength range. What is this trying to tell me? Like if I specify 70 ksi for whatever, reason, and the range in column 2 for that strength is 15 ksi, what is the range for?

 

[GBTorpenhow]

I would guess that it gives the upper limit on tensile strength to maintain weldability, toughness, etc.

So specifying 70 ksi tensile would get you material within the range of 70-85 ksi tensile.

 

[goutam_freelance]

Specifying a very hard washer material may damage the base material itself. So I prefer a little softer material than the base material.

Also if corrosion is present, some protection may be necessary.

Engineers, think what we have done to the environment !

https://www.linkedin.com/in/goutam-das-59743b30/

 

[leekuo]

* Washer hardness must be greater than the hardness of the mating surfaces in order to assure its mechanical function