Australian 316 stainless - the good, bad & ugly

[Alii]

Four years ago we refit in Queensland and went to incredible effort to buy fasteners, plumbing parts, etc. made of quality 316 stainless. At least six different vendors assured us they were supplying top-quality Aussie-made 316, not cheap Chinese imports. Four years on we are replacing a good amount of this rusty junk, and continually cleaning up after what will remain in place.

Note that there is no "excellent" category in this report.

Good - This Tridon T-bolt is an example of how one would expect acceptable 316 to perform. A bit of pitting and rust but not so bad as to turn everything around it dirty red. This particular T-bolt clamped the engine intake hose to the sea strainer, probably got moist with condensation but was never exposed to salt water for any extent of time, or to chemicals or fuel.

Bad - just about every fastener -- screw, bolt, nut, washer -- started to rust within a month of installation. Exterior fasteners quickly created rivers of rusty stains on surrounding white surfaces.

Ugly - These 90-degree pipe elbows, special ordered, are among the worst. The freshly-painted bilge was promptly ruined by their rusty run-off. They have corroded inside and out, threads failing and leaking.

These pieces are in stark contrast with the 28-year-old Swedish-made stainless that remains on our boat. If doing repairs in Australia, consider looking elsewhere if you want 316.

[Coops]

Where did you buy the 316 fasteners from?

Coops.

[Reefmagnet]

Don't believe everything the salesman tells you. I'm not sure if there's that much Australian manufactured stainless steel, if any, these days. In any event, Swedish stainless steel is considered the best and probably Japanese the next.

[IslandHopper]

Originally Posted by Reefmagnet

Don't believe everything the salesman tells you. I'm not sure if there's that much Australian manufactured stainless steel, if any, these days. In any event, Swedish stainless steel is considered the best and probably Japanese the next.

There's bugger all, stainless steel manufacturing in Australia went down the tubes years ago, you have mobs like Home who promote SS in Aus, but the vast amount is imported for use....

Any form of steel manufacturing in Aus died years ago, there are a couple of manufacturers hanging in there, but it's only a matter of time before they succumb to the cheaper imports....it's just not financially viable to produce here anymore.....

[mischief]

Alli
Did the 316 SS they sell you have zero magnetic reaction?

The reason I ask is when I source my 316 I always check it with a large rare earth magnet. Often I find they stick and I reject it or use it believing it is inferior and likely a different grade being passed off and therefore only used where I could accept that (which is usually not on my boat).

I've never been too overly concerned beyond my test as anything that passes my magnet test seems to last without rusting just fine so I assume this is an adequate test.

I would sure like to know if that's not the case.

BTW I do not find a standard magnet as sufficient for testing and only use rare earth which I can tell lower 304/ 305 apart from 316 quite easily.

In Australia I've had some items trying to be sold to me as 316 that would stick like iron to the magnet.

When I scoffed at the item the salesman tried to assure me its top quality. Yeah right!


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[GordMay]

The magnet test is useful, but not always fail-safe. Some excellent S/S parts may sometimes exhibit some ferromagnetic attraction.

The 400 series of stainless steel is the cheapest. It doesn’t usually contain nickel, making it Martensitic, and therefore ferromagnetic.

The 300 series of stainless steel is an Austenitic, non-magnetic, type of stainless steel.

However, if austenitic stainless steels are cold worked, they can behave as "partially" ferromagnetic, showing some attraction to a permanent magnet. With complex shape formed components the partial magnetic attraction is usually non-uniform and is more marked at formed corners or near drilled holes or machined faces. This uneven distribution is often useful in confirming the steel as an austenitic type. This variation in attraction to a magnetic does not occur with other stainless steels, or carbon steels.

Cast austenitic grades are likely to crack in the casting process if they aren’t formulated to be somewhat magnetic – the same applies to welds. So castings are usually magnetic, unless they have been heat treated.

Stainless steel bolts are made by cold forging the head, and cold rolling or machining the thread. They are often quite strongly magnetic. The austenitic grades with higher nickel, like 316, show much lower magnetic response.

[CLady]

Wow!--Youare the source! This thread is awesome--thanks!

[Cadence]

Originally Posted by Alii

Four years ago we refit in Queensland and went to incredible effort to buy fasteners, plumbing parts, etc. made of quality 316 stainless. At least six different vendors assured us they were supplying top-quality Aussie-made 316, not cheap Chinese imports. Four years on we are replacing a good amount of this rusty junk, and continually cleaning up after what will remain in place.

Note that there is no "excellent" category in this report.

Good - This Tridon T-bolt is an example of how one would expect acceptable 316 to perform. A bit of pitting and rust but not so bad as to turn everything around it dirty red. This particular T-bolt clamped the engine intake hose to the sea strainer, probably got moist with condensation but was never exposed to salt water for any extent of time, or to chemicals or fuel.

Bad - just about every fastener -- screw, bolt, nut, washer -- started to rust within a month of installation. Exterior fasteners quickly created rivers of rusty stains on surrounding white surfaces.

Ugly - These 90-degree pipe elbows, special ordered, are among the worst. The freshly-painted bilge was promptly ruined by their rusty run-off. They have corroded inside and out, threads failing and leaking.

These pieces are in stark contrast with the 28-year-old Swedish-made stainless that remains on our boat. If doing repairs in Australia, consider looking elsewhere if you want 316.

Sounds like they sold you poor quality 416?

[Cheechako]

Originally Posted by GordMay

The magnet test is useful, but not always fail-safe. Some excellent S/S parts may sometimes exhibit some ferromagnetic attraction.

The 400 series of stainless steel is the cheapest. It doesn’t usually contain nickel, making it Martensitic, and therefore ferromagnetic.

The 300 series of stainless steel is an Austenitic, non-magnetic, type of stainless steel.

However, if austenitic stainless steels are cold worked, they can behave as "partially" ferromagnetic, showing some attraction to a permanent magnet. With complex shape formed components the partial magnetic attraction is usually non-uniform and is more marked at formed corners or near drilled holes or machined faces. This uneven distribution is often useful in confirming the steel as an austenitic type. This variation in attraction to a magnetic does not occur with other stainless steels, or carbon steels.

Cast austenitic grades are likely to crack in the casting process if they aren’t formulated to be somewhat magnetic – the same applies to welds. So castings are usually magnetic, unless they have been heat treated.

Stainless steel bolts are made by cold forging the head, and cold rolling or machining the thread. They are often quite strongly magnetic. The austenitic grades with higher nickel, like 316, show much lower magnetic response.

Yep... even aircraft certified austenitic SS with certs/papers can be magnetic due to the manufacturing cold work....

[Kenomac]

I think the cheap junk stainless somehow got mixed in with the good stuff, whether by accident or on purpose.

We have quality stainless on our boat that 13 years old that never shows any rust and looks new. Your situation demonstrates the very real problem. I've purchased stainless steel items from the China stores in Spain that have held up well, and some stainless things from good stores that have corroded. The good gets mixed with the bad and one never knows the quality unless one knows the actual source of the goods.

When I replaced all the bronze skin fittings last year, I made sure I knew the source, spoke with the company metallurgist and knew the composition of the bronze. Also made sure they were made in the USA. Europe also has some quality bronze made in Italy. Gotta do your homework, but even then you can get burned. Good luck.

[Sand crab]

Or you could just get the titanium ones and never have to worry again. They are pricey but are much stronger especially in an alloy and resist corrosion better than anything else. They are also essentially non-reactive so just bolt that stainless doohickey to the aluminum whatchamacallit. Throw some copper in there too because titanium doesn't care.

[leftbrainstuff]

You can never trust a salesman. I only buy stainless fasteners from trusted sources. That is with known stamping and from a known supplier. Australia is now flooded with junk fasteners. The collapse of manufacturing and the loss of our engineering capability is in part to blame.

We're now based in the USA where thankfully I can even buy good stainless fasteners from my local Ace hardware. Not to mention the strong engineering thinking that exists in the USA that makes so much good quality equipment readily available.

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[leftbrainstuff]

Originally Posted by GordMay

The magnet test is useful, but not always fail-safe. Some excellent S/S parts may sometimes exhibit some ferromagnetic attraction.

The 400 series of stainless steel is the cheapest. It doesn’t usually contain nickel, making it Martensitic, and therefore ferromagnetic.

The 300 series of stainless steel is an Austenitic, non-magnetic, type of stainless steel.

However, if austenitic stainless steels are cold worked, they can behave as "partially" ferromagnetic, showing some attraction to a permanent magnet. With complex shape formed components the partial magnetic attraction is usually non-uniform and is more marked at formed corners or near drilled holes or machined faces. This uneven distribution is often useful in confirming the steel as an austenitic type. This variation in attraction to a magnetic does not occur with other stainless steels, or carbon steels.

Cast austenitic grades are likely to crack in the casting process if they aren’t formulated to be somewhat magnetic – the same applies to welds. So castings are usually magnetic, unless they have been heat treated.

Stainless steel bolts are made by cold forging the head, and cold rolling or machining the thread. They are often quite strongly magnetic. The austenitic grades with higher nickel, like 316, show much lower magnetic response.

400 series stainless is rarely used for fasteners but is used in deep hardening heat treated applications like pump shafts. It is martensitic in structure and magnetic.

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[Cadence]

Originally Posted by leftbrainstuff

400 series stainless is rarely used for fasteners but is used in deep hardening heat treated applications like pump shafts. It is martensitic in structure and magnetic.

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Yep, and if you want a knife blade 400 series is better, with more carbon it will hold an edge, not as good as carbon steel. It is less likely to snap when tightening. Good quality will only color rust.

[Cheechako]

Originally Posted by leftbrainstuff

You can never trust a salesman. I only buy stainless fasteners from trusted sources. That is with known stamping and from a known supplier. Australia is now flooded with junk fasteners. The collapse of manufacturing and the loss of our engineering capability is in part to blame.

We're now based in the USA where thankfully I can even buy good stainless fasteners from my local Ace hardware. Not to mention the strong engineering thinking that exists in the USA that makes so much good quality equipment readily available.

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You gotta watch where you get it and what you get in the US too! Some of the Ace stuff is pretty good, a lot better than Lowes for sure. Not sure if all Ace's are the same or not. There are Screw supply houses for commercial customers... they may be the best bet.