MS24677/NAS1352 Properties?

ThereAre4Lights · Sep 6, 2019

I am looking for Young's Modulus and coefficient of thermal expansion data for a number of fasteners, for example, MS24677/NAS1352. The spec sheets for these specify minimum tensile strength (psi) and also the specific strength of each bolt per size (lbs). However, under material it simply states "ALLOY STEEL IN ACCORDANCE WITH PROCUREMENT SPECIFICATIONS" OR "ALLOY STEEL IN ACCORDANCE WITH PROCUREMENT SPEC FF.S-86." I looked into FF.S-86 and there wasn't any more information. Looking online at suppliers of these bolts they simply state: Steel overall. Am I missing something? Can I assume any alloy? If so, which do you guys reckon would be appropriate? I'm looking into this for analysis of joint preload (incorporating thermal properties of the bolt and joint members). Any advice on how to proceed? Does 'steel overall' refer to some universally accepted generic bolt steel? Any info would be great!

hpaircraft · Sep 9, 2019

I think that if you're getting into a realm where the small difference in modulus of elasticity and thermal coefficients between different steel alloys makes an appreciable difference, then the properties differences between batches of screws, and even between individual screws in a batch will have a much greater impact on your joints.

WKTaylor · Sep 9, 2019

I won't weigh in on these bolts... rarely deal with Socket [internal hex] head cap-bolts, much less coarse thread cap-bolts.... except for certain mechanical assys that need clamp-up [only] with shear-pins for shear and alignment and lockwire for head safetying.

MS24677 Coarse thread alloy steel cap bolts.

NAS1352 Coarse and fine thread alloy steel and A286 CRES Cap bolts.

Procurement Spec FF-S-86

I found the following brochure useful

https://files.engineering.com/getfi...4b&file=SPS_Socket_Head_Fastener_Brochure.pdf

Regards, Wil Taylor

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ThereAre4Lights · Sep 16, 2019

Thanks all, I'll be looking at the resources posted.

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MS24677/NAS1352 Properties?

ThereAre4Lights

Aerospace

hpaircraft

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WKTaylor

Well-known member

ThereAre4Lights

Aerospace

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