What is a pro/con between stainless steel type 316L and 904L

[Carrera_2]

For a normal everyday user.

[Andad]

For an everyday user I see no pros or cons.

I do see an issue with the higher nickel content of 904L.

If you have a nickel allergy.

[Fredrik]

Originally Posted by directioneng

For an everyday user I see no pros or cons.

I do see an issue with the higher nickel content of 904L.

If you have a nickel allergy.

I talked to a corrosion specialist about this, 904L actually sheds less nickel than 316L in a sweat/salt water environment despite having a higher nickel content. So if you are worried about that you should go with 904L.

[Fat_ninja]

Originally Posted by Fredrik

I talked to a corrosion specialist about this, 904L actually sheds less nickel than 316L in a sweat/salt water environment despite having a higher nickel content. So if you are worried about that you should go with 904L.

Learn something everyday. Thank you

[Tools]

Maybe this will help.

https://www.rolexforums.com/showthread.php?t=113138

[SearChart]

Originally Posted by Tools

Maybe this will help.

https://www.rolexforums.com/showthread.php?t=113138

Great post Larry!!

[breitlings]

I have never had an allergy to any 316 watch, I can't wear a 904l watch for more than 24 hours without irritation. So I have to respectfully disagree with the assertion that 904l is less irritating than 316.

[Hunter87]

904-L is soft so the case can get dented that’s a con and the price you pay for it being resistant to stains

[037]

Originally Posted by Hunter87

904-L is soft so the case can get dented that’s a con and the price you pay for it being resistant to stains

Soft compared to what?

[watchmavan]

Does it matter? You don't exactly have choice. If you want the watch you take the 904L.


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[utc66]

A few years ago, I got poison ivy on my wrist in two spots. Since then when I wear my SeaDweller, after a few days, I will start to have a rash exactly where the poison ivy was. My remedy was I to switch out all the links out for aftermarket 316 links. I kept my oringnal clasp as that isn’t an area that is affected, and now I can wear the watch 24/7 for months with no problem.

Poison Ivy can cause a nickel sensitivity. I haven’t found anything on the net to prove this, but would love to hear from a dermatologist what they think. I doubt it’s ever been documented as it’s an obscure watch nerd topic.

[GreatHarry]

Originally Posted by 037

Soft compared to what?

Slightly softer than 316L.

[watchmavan]

Originally Posted by Carrera_2

For a normal everyday user.

904L is shinier and softer. For the everyday user and 99% of others, that's it.


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[214270Explorer]

Here is some info from the Wiki free encyclopedia on 904L Stainless Steel:
(BTW: Sharing is permitted per their rules of usage)

SAE 904L stainless steel

From Wikipedia, the free encyclopedia

904L is an austenitic stainless steel (*). In comparison to 316L, its molybdenum addition gives it superior resistance to localized attack (pitting and crevice corrosion) by chlorides and greater resistance reducing acids and in particular its copper addition gives it useful corrosion resistance to all concentrations of sulphuric acid. Its high alloying content also gives it greater resistance to chloride stress corrosion cracking, but it is still susceptible. Its low carbon content makes it resistant to sensitization by welding and which prevents intergranular corrosion.

It has applications in piping systems, pollution control equipment, heat exchangers, and bleaching systems.

In 1985 Rolex became the first wristwatch manufacturer to utilize 904L grade steel in its watches. Rolex chose to use this variety of steel because it takes a higher polish than other grades of steel and provides greater corrosion resistance, though it does not machine as well and requires specialized equipment to be properly modified into the required shapes.

Composition
• Nickel, 23–28%
• Chromium, 19–23%
• Carbon, 0.02% maximum
• Copper, 1–2%
• Molybdenum, 4–5%
• Manganese, 2% maximum
• Silicon, 1.0% maximum
• Iron, (balance)
Other names
• UNS N08904
• DIN 1.4539
• SUS 904L
• SS2562

(*) Austenitic stainless steel

From Wikipedia, the free encyclopedia

Austenitic stainless steel is a specific type of stainless steel alloy. Stainless steels may be classified by their crystalline structure into four main types: austenitic, ferritic, martensitic and duplex. These stainless steels possess austenite as their primary crystalline structure (face centered cubic). This austenite crystalline structure is achieved by sufficient additions of the austenite stabilizing elements nickel, manganese and nitrogen. Due to their crystalline structure austenitic steels are not hardenable by heat treatment and are essentially non-magnetic.

There are two subgroups of austenitic stainless steel. 300 series stainless steels achieve their austenitic structure primarily by a nickel addition while 200 series stainless steels substitute manganese and nitrogen for nickel, though there is still a small nickel content.
300 series stainless steels are the larger subgroup. The most common austenitic stainless steel and most common of all stainless steel is Type 304, also known as 18/8 or A2. Type 304 is extensively used in such items as, cookware, cutlery, and kitchen equipment. Type 316 is the next most common austenitic stainless steel. Some 300 series, such as Type 316, also contain some molybdenum to promote resistance to acids and increase resistance to localized attack (e.g. pitting and crevice corrosion). The higher nitrogen addition in 200 series gives them higher mechanical strength than 300 series.

[77T]

One “pro” for 316 SS is there are no lines or lists to buy those brands.

One “con” for 904 SS is the long wait list for sports models Rolex makes in the metal.


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[037]

Originally Posted by GreatHarry

Slightly softer than 316L.

904L has a tensile strength of 485 MPa where 316L is 490 MPa. That makes 904L 1% softer if we're using "soft" in metallurgic terms. That 1% difference isn't worth all the hype spread on the Internet.

[GreatHarry]

Quite so. Thanks 037.

[watchmavan]

Originally Posted by 037

904L has a tensile strength of 485 MPa where 316L is 490 MPa. That makes 904L 1% softer if we're using "soft" in metallurgic terms. That 1% difference isn't worth all the hype spread on the Internet.

Well it's probably worth as much hype as is given for it being better than 316L. So it a counter argument for both sides.


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[DLRIDES]

Originally Posted by 037

904L has a tensile strength of 485 MPa where 316L is 490 MPa. That makes 904L 1% softer if we're using "soft" in metallurgic terms. That 1% difference isn't worth all the hype spread on the Internet.

Tensile strength doesn’t necessarily give the complete story as to the “hard vs. soft” of the two alloys. Many scales can be used, but for this instance, let’s use the Brinell.

) 316L has a Brinell hardness of 146

) 904L has a Brunel hardness of 122


This dispels the internet hype that 904L is harder therefore more scratch resistant. Better corrosive properties, but not harder.

[littleolemoi]

Originally Posted by DLRIDES

Tensile strength doesn’t necessarily give the complete story as to the “hard vs. soft” of the two alloys. Many scales can be used, but for this instance, let’s use the Brinell.

) 316L has a Brinell hardness of 146

) 904L has a Brunel hardness of 122


This dispels the internet hype that 904L is harder therefore more scratch resistant. Better corrosive properties, but not harder.

One learns something new every day!!

I never knew there was a hardness scale and thought hard was ummm " hard " which I was good with ahem ahem!?

Thank you!

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[037]

Originally Posted by DLRIDES

Tensile strength doesn’t necessarily give the complete story as to the “hard vs. soft” of the two alloys. Many scales can be used, but for this instance, let’s use the Brinell.

) 316L has a Brinell hardness of 146

) 904L has a Brunel hardness of 122


This dispels the internet hype that 904L is harder therefore more scratch resistant. Better corrosive properties, but not harder.

Brinell hardness is rarely used on austenitic steels. Rockwell B (HRBW) is a far better and more widely accepted scale for alloys like 316L and 904L. And, depending on how they're alloyed, Rockwell harness might only be 5 points apart between the two and typically fall somewhere in the HRBW 70 to 95 range -- likely 90~95 in this case. This still isn't "soft" to the point where 904L is like gold and 316L like steel as it seems to be assumed here.

904L might be slightly softer than 316L but in no way is it a "soft" metal. That's the main point I was making above.

Besides, if both steels are forged in manufacturing then their Brinell hardness (if using that scale for debate purposes) will be closer together than the 146/122 numbers you posted above. I suspect they'd only be a few points apart. The numbers you quoted are for raw materials, not forgings. Rolex forges their cases but might not forge their bracelets, which are likely made from extrusions. We'd need to test each part before claiming the end-all debate on hardness numbers. This is why I went with tensile strength.

IMO this debate in "904L softness" is WAY overblown. Any event that will scuff, scratch or dent 904L will equally affect 316L.

[stanc1]

316L is the most common type of stainless steel used for watches

[DLRIDES]

Originally Posted by littleolemoi

One learns something new every day!!

I never knew there was a hardness scale and thought hard was ummm " hard " which I was good with ahem ahem!?

Thank you!

[handsfull]

Originally Posted by 037

Brinell hardness is rarely used on austenitic steels. Rockwell B (HRBW) is a far better and more widely accepted scale for alloys like 316L and 904L. And, depending on how they're alloyed, Rockwell harness might only be 5 points apart between the two and typically fall somewhere in the HRBW 70 to 95 range -- likely 90~95 in this case. This still isn't "soft" to the point where 904L is like gold and 316L like steel as it seems to be assumed here.

904L might be slightly softer than 316L but in no way is it a "soft" metal. That's the main point I was making above.

Besides, if both steels are forged in manufacturing then their Brinell hardness (if using that scale for debate purposes) will be closer together than the 146/122 numbers you posted above. I suspect they'd only be a few points apart. The numbers you quoted are for raw materials, not forgings. Rolex forges their cases but might not forge their bracelets, which are likely made from extrusions. We'd need to test each part before claiming the end-all debate on hardness numbers. This is why I went with tensile strength.

IMO this debate in "904L softness" is WAY overblown. Any event that will scuff, scratch or dent 904L will equally affect 316L.

Truth is, Ive owned and worn both steels...316 for decades. Lab results are fun to read, but i have my real world experience and its proven beyond a doubt that 316 is far less scratch prone that 904. Exceptionally less dent prone also.

[037]

Originally Posted by handsfull

Truth is, Ive owned and worn both steels...316 for decades. Lab results are fun to read, but i have my real world experience and its proven beyond a doubt that 316 is far less scratch prone that 904. Exceptionally less dent prone also.

Post photos. Engineers don't work from anecdote alone.

Given that Rolex hasn't offered a 316L case in what seems like forever, it's not like there's a choice. Even if 904L were as soft as 18K you'd only have a choice between Rolex stainless and some other brand. Even replacement parts for 316L Era watches are typically 904L. That's why I'm sticking with the opinion of it being blown out of proportion. Your mileage may vary.

[yannis]

Originally Posted by littleolemoi

One learns something new every day!!

I never knew there was a hardness scale and thought hard was ummm " hard " which I was good with ahem ahem!?

Thank you!

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