Stainless or what?

Clyde_Wanderer

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Picked up two double ended bolts this morning for through mast which hangs the shrouds.
I had these bolts made in an engineering place in Clydebank.
After I got them, I checked them with a magnet as I dident think they looked like the 316 I had asked for, turns out they are magnetic, took them back to be told they were 303 s/s which I must say I have never heard of.
Has anyone came across this type of steel and do you think it would rust or corrode?
Thanks.
 

cliff

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Stainless steel type 1.4305 is popularly known as grade 303 stainless steel. Grade 303 is the most readily machineable of all the austenitic grades of stainless steel.

The machineable nature of grade 303 is due to the presence of Sulphur in the steel composition. Whilst the Sulphur improves machining, it also causes a decrease in the corrosion resistance and a slight lowering of the toughness. The corrosion resistance of type 303 is lower than that for 304. The toughness is still excellent as with other austenitic grades.

There is another grade called 303SE which has Selenium added instead of Sulphur but agian the corrosion resistance suffers

In other words "Take it back" - it is not anywhere near 316 in term of corrosion resistance and if you specified 316 that is what you should have received.

BTW did you ask for 316L 316 or 316H /forums/images/graemlins/grin.gif
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Richard10002

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[ QUOTE ]
BTW did you ask for 316L 316 or 316H /forums/images/graemlins/grin.gif


[/ QUOTE ]

The differences being? /forums/images/graemlins/grin.gif
 

cliff

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Grade 316L, the low carbon version of 316 and is immune from sensitisation (grain boundary carbide precipitation). Thus it is extensively used in heavy gauge welded components (over about 6mm). Grade 316H, with its higher carbon content has application at elevated temperatures, as does stabilised grade 316Ti.

The austenitic structure also gives these grades excellent toughness, even down to cryogenic temperatures.

Next question? /forums/images/graemlins/grin.gif
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Clyde_Wanderer

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Hi Cliff.
Thanks for reply.
I took them back withen 15min of getting them.
Just specified A4/ 316 which I had even wrote on the drawing.
I think they must have had the 303 leying about and used it to save ordering in 316.
 

cliff

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Be aware that even though the 300 series stainless steels are austenitic they can, and frequently do, exhibit slight magnetic properties. The 400 series being martensitic exhibit much stronger magnetic properties.
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Birdseye

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those terms relate to the chrystalline structure of the steel. normally 18/8 steels are austenitic and therefore non magnetic. they cannot be hardened and tempered to produce higher strength, but cold working does produce some martensite within the materialand cold working does increase tensile strength. martensite is magnetic so colsd worked austenitic steels start to become magnetic.

martensitic stainless steels contain mostly chrome as alloying lements. they can be hardened and tempered but are nothing like as corrosion resistant. common example are old fashioned knife blades or stainless razor blades.

there are free machining versions of type 316. we used to make one with copper in it so that corrosion resistance didnt reduce. dont know whether it is still made since the industry (like most else in the UK) has all but disappeared and is foreign owned. sad since we invented stainless, as well as modern steel making.
 

FAITIRA

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Well Cliff, if Ihave any questions relating to metals, Iwill refer them to you Sir, i,m a fitter and turner by trade, but very impressed! Bill.
 

cliff

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[ QUOTE ]
Did you know all that Cliff or did you google it?...:p /forums/images/graemlins/wink.gif

[/ QUOTE ] /forums/images/graemlins/laugh.gif
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cliff

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[ QUOTE ]
Cliff is a metallurgist!

[/ QUOTE ]Yep, I can even take one look at a platinum blonde and tell whether it is virgin metal or common ore /forums/images/graemlins/grin.gif
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cliff

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Ah, now that is part of the training, grasshopper. That skill only comes with experience and to give away the secret to the un-initiated could see me struck of the rolls of the Ancient Order of Alchemists - oops sorry Metallurgists - We are even more protective of our secrets than other Ancient Orders /forums/images/graemlins/grin.gif
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