Flexible Hose Brackets - what type of steel?

[petepetrolhead]

I'm wondering what kind of steel these brackets are made from? If they're mild steel then they'll need coating to be rust proof, but if they're stainless steel I can leave them natural. Thanks for your help. 212994

[gbranham]

I don't believe they're stainless...I seem to remember mine getting some surface rust on them before I installed them. I scuffed, primed, and painted black.

Greg

[Jeff Kleiner]

They're stainless. But stainless will indeed rust...how much depends on the chromium content of the particular grade.

Jeff

[Dgc333]

If they are a 300 series alloy there is no iron in the makeup and will not rust. If they are 400 series there is iron in the makeup and can form rust over a much longer time. Easy check is 400 series will be slightly magnetic.

[J R Jones]

Rust is a strong interpretation. This is known as “tea staining”, a common cause of the discoloration of Stainless Steel surfaces.
Although a cosmetic issue only tea staining does not affect the structural integrity or lifetime of the material, it makes the appearance of initially pristine stainless steel, unattractive.
Tea staining is also known as or often referred to as: Coastal corrosion, Brown spots or marks on stainless steel.
High grade stainless is not magnetic, but as DGC says the more iron content, the more magnetic SS is. I have seen 409 and 430 stainless exhaust parts that do not look good without the stain.
jim

[petepetrolhead]

If they are a 300 series alloy there is no iron in the makeup and will not rust. If they are 400 series there is iron in the makeup and can form rust over a much longer time. Easy check is 400 series will be slightly magnetic.

Good shout - thanks for that! I checked, and indeed the brackets are slightly magnetic, so looks like they are 400 series stainless. This also checks with Greg's experience of slight surface rust.

[Jhinkemeyer]

If they are a 300 series alloy there is no iron in the makeup and will not rust. If they are 400 series there is iron in the makeup and can form rust over a much longer time. Easy check is 400 series will be slightly magnetic.

Just to not mislead others reading this, there is absolutely iron in 300 series stainless steel (lots of it)! They are primarily iron, often around 65-70% iron is pretty common depending on the specific alloy. The magnet "trick" does generally work to ID a 300 series alloy, but it doesn't have to do with the lack of iron.

Read this (https://www.eclipsemagnetics.com/resources/guides/are-all-stainless-steels-magnetic/) if you're interested, or hit the Google.

[Dgc333]

Just to not mislead others reading this, there is absolutely iron in 300 series stainless steel (lots of it)! They are primarily iron, often around 65-70% iron is pretty common depending on the specific alloy. The magnet "trick" does generally work to ID a 300 series alloy, but it doesn't have to do with the lack of iron.

Read this (https://www.eclipsemagnetics.com/resources/guides/are-all-stainless-steels-magnetic/) if you're interested, or hit the Google.

I stand corrected. I have been under the belief that 300 series stainless was predominately Nickel and Chromium.

[michael everson]

Those are the older steel ones. Stainless is more silver looking.
Mike

[petepetrolhead]

Those are the older steel ones. Stainless is more silver looking.
Mike

Thanks for your reply Mike. I don't know why they came out so grey looking in the photo - to the eye they are definitely much more silver looking. The attraction to a magnet is very weak, so I'm inclined to believe they are stainless.