Trouble Interpeting a material spec SAE 40 B 37

moreisles · Dec 1, 2015

We have a new customer and has asked us to quote a turned part from
SAE 40 B37 and heat treat harden to grade 5 specifications. None of our metal suppliers can provide an equivalent material and will not certify to this spec. Can anyone shed some light on this? I'm new to the forum and will gladly help others where I can.

TimRD · Dec 1, 2015

Welcome to PM.

SAE 40 is UNS 83600 for Leaded Red Brass. Is it bar stock material that you are making fasteners out of?

If you can tell us more about what you are making out of it that would help greatly.

moreisles · Dec 1, 2015

It will be turned from bar 1.250" bar stock It is 3.57" overall with a M12 X 1.75 -6G thread for 2.2". The top has a diamond knurl and the part is used in a plastic injection insert mold. What is the B 37? Is that the annealed state of the UNS83600? Also, does the heat treat harden to grade 5 make sense?

Matt_Maguire · Dec 1, 2015

I'm used to seeing SAE copper alloys with the prefix "CA" and then the number - like CA110 or whatever.

Go back to the customer for chemistry. If it even "looks" like a capscrew it's likely 1x40, 3x40 or 4x40. Or ask your suppliers if your designation even makes sense to them.

Good luck
Matt

TimRD · Dec 1, 2015

The heat treating to harden it to a grade 5 doesn't make sense for this material. You could stress relieve it, but it would not respond to a heat treatment to harden it. It is one of the softer brass alloys.

The B37 is a mystery to me. I haven't been able to turn anything up here. ASTM B505 looks to be the relevant standard for the round bar to me. No mention of any post processing or alternate alloys that would have the B37 suffix. I will keep looking though.

I would go back to the customer and ask them to clarify what material they are using. There are heat treatable brass alloys that may be able to give you the strength that they are looking for.

moreisles · Dec 1, 2015

Matt,
Thanks for your help. I agree with your statement and for a major corporation to have this as a material spec is frustrating. They have a crop of young engineers that are with all respect sometimes difficult to interact with on similar issues...

johnoder · Dec 1, 2015

Scan from 1943 SAE Handbook. No possibility of "heat treat" here, just properties to be expected as cast, and Chemistry

wesg · Dec 1, 2015

Looks to me they want 4037B, which is a designation for the addition of Boron to a Molybdenum steel.

40B37 may have been an old designation. Couple things came up searching.

moreisles · Dec 2, 2015

Thank you for your insight wesg. I will follow the 4037B trail, The drawing clearly states SAE 40 B37. It is on 3 different but similar parts that we would love to get the contract. I will also take another run at purchasing and the relevant engineer.

johnoder · Dec 2, 2015

Be sure and consider 40B37 would likely require a mill run to get any of it.

Iceman Motorsports · Dec 2, 2015

We make millions of fasteners out of 4037 but not 40B37. Use a lot of 10B21, 10B35, etc but never 40B37.

Matt_Maguire · Dec 2, 2015

That's gotta be it moreisles, but a boron added 4037 is likely going to be hard to find. The chromium steels 50B50 & 50B60 for hand tools & springs are out there & specified just like that.

ASM 8 shows data for straight 4037 bolts (hardenability & fatigue) & gives mechanical properties of the specimens in grade 7 condition.

You may be left with using a more available material and using the ideal diameter spec for heat treating. This really should come from the designer.

Good luck
Matt

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