Steel bolts vs stainless

Can I use steel bolts in place of stainless? I ordered stainless online and only have steel locally. Im hoping it would be okay to run with until then. I would be using brass nuts with them.

pictureguy said:

Can I use steel bolts in place of stainless? I ordered stainless online and only have steel locally. Im hoping it would be okay to run with until then. I would be using brass nuts with them.

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A Grade 8 steel bolt is stronger than the 300 series stainless. It's only compatibility issue is corrosion, which wouldn't be an issue short term.

We used three Grade 8 bolts in our 12" ASME clamps and replaced them and nuts regularly.

Here's my procedure for using brass nuts:

- Carefully remove them from each clamping bolt.
- Thoroughly clean them with acetone so no oil residue remains on them
- Put them all in a bucket
- throw them in the nearest dumpster

Brass nuts are supplied with stainless bolts on sanitary clamps since their primary use is in the food and beverage industry where they are subjected to washdown multiple times daily, and get washed with harsh chemicals like caustic at least once a day.

Stainless nuts will gall and brass is the easiest material to use that resists corrosion.

However... The turds supplied with anything but Alfa or Tri-Clover clamps are poorly made and strip easily. (any Chinese made nuts)

You can use steel nuts on stainless bolts, or steel bolts with steel nuts. Either will be safer than those useless Chinese brass things.
The possibility of one cracking or letting go during an extraction is real.

Brass nuts also get flared on the ends making it hard to get a socket on them.

As GW notes, replace them regularly.

/rant over

TLDR:
Steel bolts are fine. better to use with steel nuts.

Peace.
RB

Could I use a harder 410 stainless bolt (if those are manufactured) and 304 stainless nuts? To prevent galling because one is harder, while maintaining all stainless steel

If stainless bolts work with steel nuts, would steel bolts work with stainless nuts?

Rickys bong said:

Brass nuts are supplied with stainless bolts on sanitary clamps since their primary use is in the food and beverage industry where they are subjected to washdown multiple times daily, and get washed with harsh chemicals like caustic at least once a day.

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I used to work in an ethanol production facility (non-cannabis, for Biofuel) and we utilized brass nuts with brass tools for employee safety. I was under the impression the brass was non-sparking and could reduce the risk of an explosion if something were leaking. I could be wrong though as this was almost a decade ago and early in my career.

I think im going to upgrade to asme clamps. I found a vendor who offers them for only double the price of high pressure clamps and figured it might just be better to upgrade. Anything I should know about these?

pictureguy said:

Could I use a harder 410 stainless bolt (if those are manufactured) and 304 stainless nuts? To prevent galling because one is harder, while maintaining all stainless steel

If stainless bolts work with steel nuts, would steel bolts work with stainless nuts?

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Yes, but tension them properly. Typically about 65% of proof load. Over tension not only galls but stretches the threads.

Here is an exert from an article on bolt galling from Fastenal:

https://www.fastenal.com/content/documents/FastenalTechnicalReferenceGuide.pdf

Galling
Thread galling is a common, yet seldom-understood problem with threaded fasteners. Galling is oftenreferred to as a cold-welding process, which can occur when the surfaces of male and female threads come in contact with heavy pressure. The truly annoying aspect of fastener galling is that these same nuts and bolts are found to meet all required inspections (threads, material, mechanical, etc.), but yet they are still not functioning together.

Stainless steel fasteners are particularly susceptible to thread galling, although it also occurs in other alloys which self-generate an oxide surface film for corrosion purposes, such as aluminum and titanium. During the tightening of the fastener, a pressure builds between the contacting thread surfaces and breaks down the
protective oxides. With the absence of the oxide coating, the metal high points can shear and lock together.

Minor galling may cause only slight damage to the thread surface and the fastener may still be removed. However, in severe cases, galling can completely weld the nut and bolt together and prevent removal of the fastener. Often times, once galling begins, if the tightening process is continued, the fastener may be twisted off or its threads stripped out.


Unfortunately, even with an understanding of the mechanism of galling, little is known on how to successfully control it. However, the probability of galling occurring can be minimized with the following measures:
•
Thread lubrication is one of the most effective measures to lessen the potential for galling. The lubricant reduces friction, which is a key element in thread galling. Certain material environments,
such as stainless steel fasteners used in food processing equipment, preclude the use of some lubricants. Also, attention must be given to the torque-tension relationship, which will be altered with the use of lubrication.
•
Use coarse threads with a 2A-2B fit instead of fine threads. Coarse threads have a larger thread allowance and are more tolerant to abuse during handling.
•
Heat contributes significantly to thread galling. Installing a fastener generates heat and high-speed installation generates significantly more heat. Lowering the wrench speed during installation and removal can be helpful.
•
Avoid prevailing torque locknuts. The function of a prevailing torque locknut is to add resistance to the threads. This resistance also creates friction and heat. If a prevailing torque locknut must be used, ensure a minimal amount of threads are protruding beyond the nut.
•
Mating parts of the same alloy have a greater tendency to gall than parts of dissimilar alloys having different degrees of hardness. Most stainless steels are more susceptible to galling than carbon and alloy steels. However, not all combinations of stainless steels act the same. For instance, a 400 series stainless steel nut can work well on 316 series bolts, but with a reduction in corrosion resistance.
•
A smoother surface texture will lead to less frictional resistance. Rolled threads usually offer smoother surfaces than cut threads. As previously mentioned, friction increases the possibility of
galling.
•
Proper installation torque. If the fastener is over tightened, the threads can begin to yield which will induce friction between the mating surfaces.

Ions71 said:

I used to work in an ethanol production facility (non-cannabis, for Biofuel) and we utilized brass nuts with brass tools for employee safety. I was under the impression the brass was non-sparking and could reduce the risk of an explosion if something were leaking. I could be wrong though as this was almost a decade ago and early in my career.

Click to expand...

Brass is non sparking, but also not very strong. Silicone bronze is typically used where self lubricating and non sparking properties are desired.