Looking for hardware grade 5 socket head screws
Looking for hardware grade 5 socket head screws
(OP)
I am having difficulty locating someone that sells grade 5 ASTM-A449 socket head screws. I need 3/4-10 x 1.75 long. Any help would be appreciated. I am needing something in the 130 ksi range.
Thanks
Dale
Thanks
Dale
Thanks
Dale





RE: Looking for hardware grade 5 socket head screws
Socket head cap screws usually are supposed to be high strength, unless they are stainless. Do you need approximately 130ksi, or at least 130ksi?
Why such a specific alloy? Do you have inspection and certification issues?
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JHG
RE: Looking for hardware grade 5 socket head screws
Thanks
Dale
RE: Looking for hardware grade 5 socket head screws
RE: Looking for hardware grade 5 socket head screws
Thanks
Dale
RE: Looking for hardware grade 5 socket head screws
Ted
RE: Looking for hardware grade 5 socket head screws
I agree with this.
Also, this statement:
rules out Grade 5 fasteners.....
Damage to fastener threads could be caused by number of things.
Before changing the material, I'd take at look at
1) fastener length. If the fasteners are too short, you won't have enough thread engagement. This increases the load on each thread and if you only have a couple threads engaged, you can ruin fasteners- grade 8 or not. You want 2x bolt diameter of thread engagement length, at minimum, to fully develop the strength of whatever fastener you are using.
2) Installation torque. 120ft-lbs is extremely low for a 3/4" fastener. You're not generating very much preload- and if the fasteners are 3/4, I have to assume the product is designed to be mounted with a high level of preload.
In short, buy fasteners that are the correct length and torque them correctly before you go chasing a problem that's harder to solve.
RE: Looking for hardware grade 5 socket head screws
My cheat sheet shows 375ft-lb min.
With loose bolts rattling around no wonder you got thread damage.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: Looking for hardware grade 5 socket head screws
Metric ones are more like coelecanths and less like unicorns.
But the comments by others about tightening are well heeded.
RE: Looking for hardware grade 5 socket head screws
RE: Looking for hardware grade 5 socket head screws
Most material from what I've seen for armor plate typically work hardens, the Hadfield Manganese we use definitely does.
It sort of sounds like to me that you are getting some sort of galling.
It is very common with the stainless steel nuts and bolts and even screw shackle threads.
You can hand thread the parts together and they just lock up when you try to take them apart.
My guys in the shop have presented me with many examples of this over the years.
We use silver anti-seize to prevent that from happening.
RE: Looking for hardware grade 5 socket head screws
-the torque we are using is based on what is used in the field for mounting the assembly. It is 155 ft lbs, not 110.
-limited to requirements given by our customer.
-we know the fastener is the correct length but it is only 1.75" long.
-we may look at a coating to help with the galling, which is probably what is happening.
Thanks
Dale
RE: Looking for hardware grade 5 socket head screws
The thread engagement is what counts. Is that the same as in service?
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A449-04b Specification for Hex Cap Screws, Bolts, and Studs, Steel, Heat Treated, 120/105/90 ksi Minimum Tensile Strength, General Use
I don't think ASTM A449 covers SHCS. Is the product retained by Hex head cap screws or Socket Head cap screws in service ?
I'd bet a nickel there is a detailed procedure for installation including torque and fastener lubrication requirements.
RE: Looking for hardware grade 5 socket head screws
Dick
RE: Looking for hardware grade 5 socket head screws
In other words, the surface of a grade 5 bolt is not that much softer than the surface of a grade 8 bolt- so just dropping to grade 5 likely won't solve your problem, as the galling mechanics won't change very much.