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Stainless Steel grades
- Thread starter crumpdaddy
- Start date
I believe this topic has been discussed before... The higher the grade, the more shine it will posses (i.e: retaining that shiny look) and more corrosive resistant.
Rolex uses grade 900 something... and those who claims to have grade 440 in a rep may not be true at all (typical description in scam sites). Yes 316 tends to be better (i.e: cost more) than 220.
No wonder those gen Rollie bracelets costs so much.
I am learning more and more about this craft. Thanks sir!
I am learning more and more about this craft. Thanks sir!
yes... cost of production for those bracelet is about 3-4 times of our rep SS.
THings to note... the higher the grade, the higher the nickel contents. Some skins are sensitive to high nickel content.
THings to note... the higher the grade, the higher the nickel contents. Some skins are sensitive to high nickel content.
takashi's coooooorect. Basically, Stainless Steel is made by adding chromium to low carbon steel. As chromium is corrosion-resistant, it gives steel it's stain resistance (i.e. "Stainless" Steel!). In addition to iron, carbon, and chromium, stainless steel may also contain other elements, such as nickel, niobium, molybdenum, and titanium. Materials such as nickel, molybdenum, niobium, and chromium all add to the corrosion resistance of stainless steel. Usually, a minimum of 12% chromium is added to the steel that makes it resist rust, or stain 'less' than other types of steel. The nickel stuff is what we're interested in, and explained below.
Now, here comes Mr. Science. The chromium added to the steel combines with oxygen in the atmosphere to form a very thin, invisible layer of chrome-containing oxide. This is called the "passive film". If the metal is cut or scratched and the passive film is damaged, more oxide will quickly form and recover the exposed surface, protecting it from corrosion. Regular steel or iron rusts quickly because atomic iron is much smaller than its oxide, so the oxide forms a loose rather than tightly-packed layer and flakes away. The passive film requires oxygen to self-repair, so stainless steels have poor corrosion resistance in low-oxygen or harsh environments such as water (particularly seawater). In seawater, salt will attack and destroy the passive film faster than it can be repaired in a low oxygen environment. This is one reason why watches take a beating when worn while sweating..........salty bad!!!!!!!
There are basically three types of stainless steel. These are called austenitic, ferritic, and martensitic. Austenitic steels have austenite as their primary makeup, and consist of chromium and nickel (actually iron, 18% chromium, and 8% nickel. Heat treating doesn't work on Austenitic steel. Surgical stainless steel is an austenitic steel containing 18-20% chromium and 8-10% nickel.
Now we got ferritic steel. This stuff contains iron and a little less chromium, which makes it a little less flexible.
The last category is Martensitic. Martensitic steel is low carbon and made up of iron, 12% chromium, and 0.12% carbon. This stuff can be tempered and hardened. It's really hard, but it also reduces its toughness and makes it brittle, so few steels are fully hardened. We don't care about no stinking ferritic or martensitic steel.
Ok, enough of the science crap. Bottom line is........
Most watches are made using Austenitic Steel, due to it's nickel content. The higher the nickel content, the more corrosion-resistant the steel is. Nickel is also very shiney, due to it's tight molecular structure (smoother surface = shinier metal, that simple!) Nickel also has a slightly different "shine" to it than, let's say chrome. A lot of people prefer nickel plating to chrome, because it has a very slight kinda-blue hue to it. Can't really tell on something as small as a watch case, but if you plate a '59 Cadillac bumper with it, you can see it.
904L Stainless steel IS slightly more corrosion resistant than industry standard 316L, which does make a difference when building sports/diving watches, as it offers a very high resistant to seawater
corrosion. BUT, nickel is an allergen, and the higher the content, the greater the chance that your arm will swell up and fall off :shock: My inside sources (mainly the pig) tell me that even Polox only uses 904L on the parts with no direct skin contact (not used on the back or band).
Well, boys and girls, there's your metallurgy tip of the day. The cow fell asleep while I was typing this :wink:
Now, here comes Mr. Science. The chromium added to the steel combines with oxygen in the atmosphere to form a very thin, invisible layer of chrome-containing oxide. This is called the "passive film". If the metal is cut or scratched and the passive film is damaged, more oxide will quickly form and recover the exposed surface, protecting it from corrosion. Regular steel or iron rusts quickly because atomic iron is much smaller than its oxide, so the oxide forms a loose rather than tightly-packed layer and flakes away. The passive film requires oxygen to self-repair, so stainless steels have poor corrosion resistance in low-oxygen or harsh environments such as water (particularly seawater). In seawater, salt will attack and destroy the passive film faster than it can be repaired in a low oxygen environment. This is one reason why watches take a beating when worn while sweating..........salty bad!!!!!!!
There are basically three types of stainless steel. These are called austenitic, ferritic, and martensitic. Austenitic steels have austenite as their primary makeup, and consist of chromium and nickel (actually iron, 18% chromium, and 8% nickel. Heat treating doesn't work on Austenitic steel. Surgical stainless steel is an austenitic steel containing 18-20% chromium and 8-10% nickel.
Now we got ferritic steel. This stuff contains iron and a little less chromium, which makes it a little less flexible.
The last category is Martensitic. Martensitic steel is low carbon and made up of iron, 12% chromium, and 0.12% carbon. This stuff can be tempered and hardened. It's really hard, but it also reduces its toughness and makes it brittle, so few steels are fully hardened. We don't care about no stinking ferritic or martensitic steel.
Ok, enough of the science crap. Bottom line is........
Most watches are made using Austenitic Steel, due to it's nickel content. The higher the nickel content, the more corrosion-resistant the steel is. Nickel is also very shiney, due to it's tight molecular structure (smoother surface = shinier metal, that simple!) Nickel also has a slightly different "shine" to it than, let's say chrome. A lot of people prefer nickel plating to chrome, because it has a very slight kinda-blue hue to it. Can't really tell on something as small as a watch case, but if you plate a '59 Cadillac bumper with it, you can see it.
904L Stainless steel IS slightly more corrosion resistant than industry standard 316L, which does make a difference when building sports/diving watches, as it offers a very high resistant to seawater
corrosion. BUT, nickel is an allergen, and the higher the content, the greater the chance that your arm will swell up and fall off :shock: My inside sources (mainly the pig) tell me that even Polox only uses 904L on the parts with no direct skin contact (not used on the back or band).
Well, boys and girls, there's your metallurgy tip of the day. The cow fell asleep while I was typing this :wink:
:lol: I like your word... "My sources are mainly pigs."
That's very elaborate explanation you have. Well done Goat!
That's very elaborate explanation you have. Well done Goat!
take a look here for all the clasifications (as you probably already know it has been discussed a while ago 
)
http://replica-watch.info/forum/viewtopic.php?t=1176
)http://replica-watch.info/forum/viewtopic.php?t=1176
as far as i know at least all daytona steel bracelets are made out of 904! thats probably why they came out with the white gold model for ppl who are alergic to nicel
btw the genuine daytona bracelets are really a lot shinier than the rep bracelets (at least i thought so when i looked at a gen post 2000 white faced daytona..... the steel on my rep didnt even come close! when the gen watch was full of fingerpringts and stuff, it looked like my daytona looked like when it came right back from polishing! and the gen polished...whohooo!)
Wow, excellent post from the Goat!
Thanks man, I didn't understand half of that, but I enjoyed it anyway!
Thanks man, I didn't understand half of that, but I enjoyed it anyway!