Interesting read on Rolex 904L Steel

[arizonapaul]

I thought this was interesting and I certainly didn't know all these cool facts. Below is copied and pasted off the net

If you ever compare a Rolex stainless wristwatch to any other stainless wristwatch, you’ll see differences because Rolex approaches stainless steel differently from other brands. Rolex approaches all its watches from a mindset of lasting durability, and the reason behind Rolex’s use of stainless steel that is different from the rest of the watch industry. Rolex utilizes 904L stainless steel for a number of technical reasons, including its highly polishable property creating a lasting, durable reflection on the watch.



Stainless steel in watches is important because of the proximately to the skin combined with sweat and moisture makes wristwatches a corrosion magnet. In order to keep the case waterproof, the threads that hold the crown and the caseback cannot corrode. Even though stainless steel is formulated to prevent rust and pits from ocean salt water and sweat, Rolex found excess wear in the caseback threads and watch case from salt water seeping into the threads and sitting undisturbed for years between watch services allowing for the steel to pit and gall. Salt and other minerals proved to be catalysts for corrosion and deterioration around the threads that hold the caseback. Noble metal wristwatches such as gold or platinum watches do not have a corrosion issue, but base metal does. Until the widespread use of stainless steel, older watches utilized primitive stainless caseback and some type of base-metal case. Nowadays, most stainless steel wristwatches are made of 316L stainless steel throughout whereas Rolex utilizes 904L stainless steel.

Rolex calls 904L stainless steel a “corrosion-resistant superalloy.” 904L differs from 316L because of extra Chromium, Molybdenum, Nickel, and Copper which gives it improved resistance to acids. 316L is considered a tougher, harder, “marine grade” steel, but it does not have luster and acid resistance of 904L.


Rolex utilizes 904L with the greatest of quality control. Once received from Rolex’s steel suppliers, Rolex casts and scans it using an electron microscope that is capable of detecting the slightest structural or surface defect. Rolex has been known to send steel back when it does not meet their exacting specifications. After casting and inspection, the steel is then re-melted in a vacuum to purify it and eliminate any inclusions that would diminish its corrosion resistance and lead to problems in polishing. 904L stainless steel does not machine well as compared other stainless steels. Subsequently, Rolex had to design its own tools to work with the material and utilizes a 250 ton press to stamp the initial cases.

Rolex started using 904L stainless steel in 1985, but it became more prevalent in the Rolex line starting in the early 2000’s transitioning from 316L. Rolex initially started with just making the watch case with 904L and kept the bracelet 316L, but since 2006, Rolex utilized 904L in both the bracelet and case. When comparing a modern Rolex with other modern Swiss watches, the visual difference is clearly noticeable. 904L has a high polish, looks warmer, and ages exquisitely. Yes, Rolex thinks of everything, including the metal that gets strapped onto your wrist.

[SemperFi]

Very interesting Paul. Thanks!

[gummy]

Good Read

[Jmals]

thanks for sharing!


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[antbkny]

love me some 904L

[SoonerTA]

Great read. Thanks for sharing

[tifosi]

Just adds to the list things to appreciate about Rolex.

[.458Chris]

I had an old 16610lv and the bracelet was not the same quality as my new 116622. I know it is an upgraded bracelet but I think the steel might make a difference as well.

[KrismanX]

I just fell in love with my watch a little more.. I digg it!

[arizonapaul]

I think I was most impressed about the part of the 904L steel being bulletproof as far as not allowing water to seep into the threads of the crown or case-back because of its materials. That and the 904L having a shine and luster like no other.
Yes we can have our cake and eat it too!!!!!

[dankatz]

Thanks for posting!!

[HogwldFLTR]

From what I understand the 316L is more scratch resistant. Tudors are still made from the 316L. I've looked at the Tudors as not having the same luster but better scratch resistance; perhaps as a PCL the 316L is a better choice.

[RHJ]

Thanks for sharing, feels still better on the wrist..

[padi56]

Originally Posted by arizonapaul

I thought this was interesting and I certainly didn't know all these cool facts. Below is copied and pasted off the net

If you ever compare a Rolex stainless wristwatch to any other stainless wristwatch, you’ll see differences because Rolex approaches stainless steel differently from other brands. Rolex approaches all its watches from a mindset of lasting durability, and the reason behind Rolex’s use of stainless steel that is different from the rest of the watch industry. Rolex utilizes 904L stainless steel for a number of technical reasons, including its highly polishable property creating a lasting, durable reflection on the watch.



Stainless steel in watches is important because of the proximately to the skin combined with sweat and moisture makes wristwatches a corrosion magnet. In order to keep the case waterproof, the threads that hold the crown and the caseback cannot corrode. Even though stainless steel is formulated to prevent rust and pits from ocean salt water and sweat, Rolex found excess wear in the caseback threads and watch case from salt water seeping into the threads and sitting undisturbed for years between watch services allowing for the steel to pit and gall. Salt and other minerals proved to be catalysts for corrosion and deterioration around the threads that hold the caseback. Noble metal wristwatches such as gold or platinum watches do not have a corrosion issue, but base metal does. Until the widespread use of stainless steel, older watches utilized primitive stainless caseback and some type of base-metal case. Nowadays, most stainless steel wristwatches are made of 316L stainless steel throughout whereas Rolex utilizes 904L stainless steel.

Rolex calls 904L stainless steel a “corrosion-resistant superalloy.” 904L differs from 316L because of extra Chromium, Molybdenum, Nickel, and Copper which gives it improved resistance to acids. 316L is considered a tougher, harder, “marine grade” steel, but it does not have luster and acid resistance of 904L.


Rolex utilizes 904L with the greatest of quality control. Once received from Rolex’s steel suppliers, Rolex casts and scans it using an electron microscope that is capable of detecting the slightest structural or surface defect. Rolex has been known to send steel back when it does not meet their exacting specifications. After casting and inspection, the steel is then re-melted in a vacuum to purify it and eliminate any inclusions that would diminish its corrosion resistance and lead to problems in polishing. 904L stainless steel does not machine well as compared other stainless steels. Subsequently, Rolex had to design its own tools to work with the material and utilizes a 250 ton press to stamp the initial cases.

Rolex started using 904L stainless steel in 1985, but it became more prevalent in the Rolex line starting in the early 2000’s transitioning from 316L. Rolex initially started with just making the watch case with 904L and kept the bracelet 316L, but since 2006, Rolex utilized 904L in both the bracelet and case. When comparing a modern Rolex with other modern Swiss watches, the visual difference is clearly noticeable. 904L has a high polish, looks warmer, and ages exquisitely. Yes, Rolex thinks of everything, including the metal that gets strapped onto your wrist.

Paul there is nothing magical about 904L SS today it was mainly a brag factor and marketing by Rolex as several other companies use 904L SS in watches XOSKELETON for one.But in the real world 904L steel was developed to be used in high salt/acid factories like for instance vinegar pickling factories etc.Now the only difference between 904L and 316L is simply this,the main difference between 316L over 904L it has slightly more Molybdenum(Mo)approx 2% more, approx 1-2% more Crome(Cr), 1% copper(Cu), and approx 10% more nickel and that's it all quite cheap comodities.And far more 316L is sold than 904L, now if it was the other way round 904L would be cheaper than 316L.There are some disadvantages to 904L it will scratch and show scratches more easily than 316L.The only advantage is, its a bit more corrosion resistant, but in the real world with today's pampered watches its doubtful if any real advantage over the industry norm 316L.And the internet myth that 904L is harder than 316L its not,but its how the metal is tempered defines its over all hardness, so 316L can be harder than 904L.

[watchnlaw]

Originally Posted by padi56

Paul there is nothing magical about 904L SS today it was mainly a brag factor and marketing by Rolex as several other companies use 904L SS in watches XOSKELETON for one.But in the real world 904L steel was developed to be used in high salt/acid factories like for instance vinegar pickling factories etc.Now the only difference between 904L and 316L is simply this,the main difference between 316L over 904L it has slightly more Molybdenum(Mo)approx 2% more, approx 1-2% more Crome(Cr), 1% copper(Cu), and approx 10% more nickel and that's it all quite cheap comodities.And far more 316L is sold than 904L, now if it was the other way round 904L would be cheaper than 316L.There are some disadvantages to 904L it will scratch and show scratches more easily than 316L.The only advantage is, its a bit more corrosion resistant, but in the real world with today's pampered watches its doubtful if any real advantage over the industry norm 316L.And the internet myth that 904L is harder than 316L its not,but its how the metal is tempered defines its over all hardness, so 316L can be harder than 904L.

Thanks for adding some insight. I've often heard quite a bit of hype about the 904L steel but even comparing side by side a Sub to a Tudor, I found it hard to notice much of a difference. I figure any visual difference between the two would likely come from finishing or from my own/our preconceived notion that the 904L is supposed to be "brighter"

[T. Ferguson]

Originally Posted by padi56

Paul there is nothing magical about 904L SS today it was mainly a brag factor and marketing by Rolex as several other companies use 904L SS in watches XOSKELETON for one.But in the real world 904L steel was developed to be used in high salt/acid factories like for instance vinegar pickling factories etc.Now the only difference between 904L and 316L is simply this,the main difference between 316L over 904L it has slightly more Molybdenum(Mo)approx 2% more, approx 1-2% more Crome(Cr), 1% copper(Cu), and approx 10% more nickel and that's it all quite cheap comodities.And far more 316L is sold than 904L, now if it was the other way round 904L would be cheaper than 316L.There are some disadvantages to 904L it will scratch and show scratches more easily than 316L.The only advantage is, its a bit more corrosion resistant, but in the real world with today's pampered watches its doubtful if any real advantage over the industry norm 316L.And the internet myth that 904L is harder than 316L its not,but its how the metal is tempered defines its over all hardness, so 316L can be harder than 904L.

If 316 is harder, I wonder how much hype is involved in the claim 904 is more difficult to machine.

[dave_dave]

Originally Posted by padi56

Paul there is nothing magical about 904L SS today it was mainly a brag factor and marketing by Rolex as several other companies use 904L SS in watches XOSKELETON for one.But in the real world 904L steel was developed to be used in high salt/acid factories like for instance vinegar pickling factories etc.Now the only difference between 904L and 316L is simply this,the main difference between 316L over 904L it has slightly more Molybdenum(Mo)approx 2% more, approx 1-2% more Crome(Cr), 1% copper(Cu), and approx 10% more nickel and that's it all quite cheap comodities.And far more 316L is sold than 904L, now if it was the other way round 904L would be cheaper than 316L.There are some disadvantages to 904L it will scratch and show scratches more easily than 316L.The only advantage is, its a bit more corrosion resistant, but in the real world with today's pampered watches its doubtful if any real advantage over the industry norm 316L.And the internet myth that 904L is harder than 316L its not,but its how the metal is tempered defines its over all hardness, so 316L can be harder than 904L.

Interesting. Good to know.

[fsprow]

Originally Posted by padi56

Paul there is nothing magical about 904L SS today it was mainly a brag factor and marketing by Rolex as several other companies use 904L SS in watches XOSKELETON for one.But in the real world 904L steel was developed to be used in high salt/acid factories like for instance vinegar pickling factories etc.Now the only difference between 904L and 316L is simply this,the main difference between 316L over 904L it has slightly more Molybdenum(Mo)approx 2% more, approx 1-2% more Crome(Cr), 1% copper(Cu), and approx 10% more nickel and that's it all quite cheap comodities.And far more 316L is sold than 904L, now if it was the other way round 904L would be cheaper than 316L.There are some disadvantages to 904L it will scratch and show scratches more easily than 316L.The only advantage is, its a bit more corrosion resistant, but in the real world with today's pampered watches its doubtful if any real advantage over the industry norm 316L.And the internet myth that 904L is harder than 316L its not,but its how the metal is tempered defines its over all hardness, so 316L can be harder than 904L.

100% correct, Peter. PhD in Materials Science here. The only additional corrosion resistance of 904 is in the presence of extremely concentrated acids, as can be found in some industrial applications - for example in heat exchangers handling sulfuric acid. It is more prone to scratches as well.

[Dirt]

Originally Posted by fsprow

100% correct, Peter. PhD in Materials Science here. The only additional corrosion resistance of 904 is in the presence of extremely concentrated acids, as can be found in some industrial applications - for example in heat exchangers handling sulfuric acid. It is more prone to scratches as well.

I have to disagree.
The long term effects on 316L in some salt water environments can be catastrophic.
Acids in perspiration are a reality which compound the issues exponentially on Wristwatches. Especially when elevated temps are thrown into the equation as found in the tropics

[padi56]

Originally Posted by Dirt

I have to disagree.
The long term effects on 316L in some salt water environments can be catastrophic.
Acids in perspiration are a reality which compound the issues exponentially on Wristwatches. Especially when elevated temps are thrown into the equation as found in the tropics

I wonder how many of todays watches no matter the metal are used in high salt water or even fresh water except for perhaps a shower or dip in the pool.Myself used my trusty 16600 SD for many years mainly around Asia and middle east Red Sea.And a Citizen Aqualand 11 for hundreds of hours underwater as dive guide, PADI, BSAC instructor..One with 904L other 316L and no problems with either,most all what you see on the net regarding pitting.Is simple down to this not being serviced and not washed and cleaned regular.

[Syed117]

Thanks Padi.

That 904L stuff is cool on paper, but it says within that text that 316 is tougher. The rest is relatively simple stuff made to sound impressive. Mostly marketing nonsense.

I'll take tougher over shinier/more acid resistant any day.

Most watches are shiny enough as it is. Especially modern rolexes.

[Abdullah71601]

Originally Posted by Syed117

Thanks Padi.

That 904L stuff is cool on paper, but it says within that text that 316 is tougher. The rest is relatively simple stuff made to sound impressive. Mostly marketing nonsense.

I'll take tougher over shinier/more acid resistant any day.

Most watches are shiny enough as it is. Especially modern rolexes.

Agree Rolex over markets 904L, but 904L has better resistance to crevice corrosion. That's worth paying for in my book. Your sweat is an enemy of 316. Thirty years from now the 904L won't have the pitting you see in 316.

The 904L alloy is more expensive to manufacture than 316 (all the high nickel alloys are). It's a misnomer to compare raw material commodity prices to alloy costs. And the high nickel SS alloys are typically more difficult to machine.

The difference in toughness in this application is irrelevant IMO. It's not cutlery. It's a fairly thick solid metal that doesn't see any stress (the lugs on a maxicase are about the same thickness as the door on my home safe). The spring bars see some stress, the links not at all, and the case only when commercial diving. In this context, shiny is better than tough.

[arizonapaul]

Originally Posted by Abdullah71601

Agree Rolex over markets 904L, but 904L has better resistance to crevice corrosion. That's worth paying for in my book. Your sweat is an enemy of 316. Thirty years from now the 904L won't have the pitting you see in 316.

The 904L alloy is more expensive to manufacture than 316 (all the high nickel alloys are). It's a misnomer to compare raw material commodity prices to alloy costs. And the high nickel SS alloys are typically more difficult to machine.

The difference in toughness in this application is irrelevant IMO. It's not cutlery. It's a fairly thick solid metal that doesn't see any stress (the lugs on a maxicase are about the same thickness as the door on my home safe). The spring bars see some stress, the links not at all, and the case only when commercial diving. In this context, shiny is better than tough.

Great points, thank you sharing.

Sent from my SCH-I545 using Tapatalk

[Dirt]

Originally Posted by Abdullah71601

Agree Rolex over markets 904L, but 904L has better resistance to crevice corrosion. That's worth paying for in my book. Your sweat is an enemy of 316. Thirty years from now the 904L won't have the pitting you see in 316.

The 904L alloy is more expensive to manufacture than 316 (all the high nickel alloys are). It's a misnomer to compare raw material commodity prices to alloy costs. And the high nickel SS alloys are typically more difficult to machine.

The difference in toughness in this application is irrelevant IMO. It's not cutlery. It's a fairly thick solid metal that doesn't see any stress (the lugs on a maxicase are about the same thickness as the door on my home safe). The spring bars see some stress, the links not at all, and the case only when commercial diving. In this context, shiny is better than tough.

Precisely.

If I may add for those who poo poo the idea that 904L is potentially easier to work with than 316 when performing machining tasks.
I say go and set up a machine shop and see how much real difference there is for yourselves in cost of production and in terms of the degree of difficulty of their respective machinability

[Abdullah71601]

Originally Posted by Dirt

Precisely.

If I may add for those who poo poo the idea that 904L is potentially easier to work with than 316 when performing machining tasks.
I say go and set up a machine shop and see how much real difference there is for yourselves in cost of production and in terms of the degree of difficulty of their respective machinability

It's been a while since I've had to deal with nickel alloy SS's, but IIRC, the main issue was chip breaking didn't work the same and the tools fouled/wore out quicker. There were some specialized tools that solved that problem.

[padi56]

Originally Posted by Abdullah71601

Agree Rolex over markets 904L, but 904L has better resistance to crevice corrosion. That's worth paying for in my book. Your sweat is an enemy of 316. Thirty years from now the 904L won't have the pitting you see in 316.

The 904L alloy is more expensive to manufacture than 316 (all the high nickel alloys are). It's a misnomer to compare raw material commodity prices to alloy costs. And the high nickel SS alloys are typically more difficult to machine.

The difference in toughness in this application is irrelevant IMO. It's not cutlery. It's a fairly thick solid metal that doesn't see any stress (the lugs on a maxicase are about the same thickness as the door on my home safe). The spring bars see some stress, the links not at all, and the case only when commercial diving. In this context, shiny is better than tough.

Yes there have been a few reports of case crevice corrosion but most of these reports were on old models.But how were these older watches used were used as working tools and not pampered like today's watches.And most I have seen were in watches that had none or little routine service in their life.As for sweat corrosion on 316L you would have to sweat bucket fulls every day.But just simple routine service and washing in good old soap and water then 316L is every way as good as 904L.After all thats whats used as the industry norm in watch cases today. So if crevice corrosion was a big problem I would have thought all watch case manufactures would use 904L.

[SS Oyster]

Originally Posted by Syed117

Thanks Padi.

I'll take tougher over shinier/more acid resistant any day.

You would like this?



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[watchwatcher]

Hmm...interesting. Thanks Paul...and Padi!

[iliketime]

is there any way to know which watches had the 904L in 1985?

[The Libertine]

Interesting read; thank you for posting. I knew the type of steel used by Rolex, but your post offers good detail as to why.