Difference between type 304 and 316 stainless steel

A. Larry Hanke suggested that 316SS is resistant to stress corrosion cracking. In fact it is not and many 316 boat fittings under stress have failed by this mechanism with sometimes dire results. 316 is usually recommended for marine atmosphere use including boats. What is not clear in the question is what constitutes the 'high saline environment'.

The Nickel Development Institute will gladly give you good technical advice on which alloy to use. Regards from 'Up Over'.

Q. Did you eventually utilize the SS-316L?
Is it withstanding the saline environment?

A. Hello Suboor!

The difference between 304L and 316L stainless steel is the roughly 2% by weight molybdenum in the 316L, and that difference gives 316L better pitting corrosion resistance in some media, such as seawater. You'll find a lot of additional information on these two austenitic stainless steels, and many other alloys, at the Nickel Development Institute website at www.nidi.org. They send out technical information for free, to further the cause of their favorite element. Much of their material is in downloadable pdf files, so it is worth the time to thoroughly peruse their site.

Another worthwhile site for stainless steel information is at www.atlas-steels.com.au/techinfo/, the technical information page from Atlas Steels, a stainless steel distributor in Australia.

Good luck!
Lee Gearhart
metallurgist - E. Aurora, New York

A. Hi, Ahmed!

You can see physical and chemicals properties of SS in following site www.matweb.com.

Good luck.

A. Being 5 km from the ocean should be sufficient in a bathroom to use 304SS. IF there is any normal problem in the area with mist from the ocean, you would want to use 316SS.

A. The sea may or may not be a problem, but the quality of the water used in the bathroom is more important.

304 will not resist corrosion as well as 316, but you also have to consider the surface toughness in this application as it will be cleaned under unknowable circumstances--perhaps using acidic and/or abrasive cleaners along with whatever trace chemicals are in the local water.

It is the oxide layer on the surface which actually prevents the SS from rusting, and the oxide layer can be injured.

316 is more resistant to acids than 304. There is a possibility that another steel would be a better choice, check with your steel supplier.

A. Hi Fahime. If you are thinking of coating something with 316L or 304L stainless steel, forget it -- you cannot electroplate or otherwise deposit stainless steel. Your only option for that is "cladding" (nickel plating sheets of stainless steel and sheets of plain steel, and then autoclaving them in a sandwich and rolling them down to a desired and do-able thickness). Good luck.

Regards,

A. Good afternoon:

304 and 316 are both austenitic stainless steels, but 316 has about 2% Mo added. In addition, the Ni and Cr composition ranges are different for these materials.

A. 316 SS also contains about 2.5% molybdenum for improved resistance to corrosion from chlorides (found in salt, seawater, sweat, etc.). Lots more info on the Internet.

The customer is always right!

A. Mr Christopher H.

I believe this enquiry stems from a concern your principal has about the corrosion resistance of stainless steel as to how long it will last once manufactured and sold, and how long will the Stainless steel remain inert to the excitement within (the alcoholic materials)

There exist a series of solutions designed for the Passivation of Regular and exotic grades of Austenitic grades of SS which function by removing the corrosion prone free iron from the surface of the SS leaving behind a Chrome and Nickel rich layer.

This effectively protects, enhances life and does not change any other characteristic leaving the surface exactly as spectacular as before.

It is well known that free iron on Stainless steel changes the taste of alcoholic beverages somewhat. These passivating solutions are made from FOOD-SAFE materials and are certified for use in Breweries.

I cannot provide commercial info but as a consultant I am findable if you wish, on this website.

Regards,

A. Mr Christopher H,

Basic difference between SS304 & S316.

First of all I tell you one thing, Both material having 16-18% Cr.
1. SS316 having high corrosive resistance in compare to SS304.

2. SS316 is more easily welded than SS304.

A. Hi there,
304 is a cheap grade,try using a magnet on it and see that it sticks to the metal.

A. Hi, Devadas. Just google this phrase: '304 stainless composition'. Each of the first dozen hits will give you what you seek.

Regards,

Hi, Mandar. Some of the salient differences have already been pointed out in this thread and other threads here. If you can please tell the readers exactly what you want to build and what environment it will see, they will probably be very happy to apply their years of experience to help you decide which way to go. Thanks!

But for the complete line-by-line differences "by the book", covering the compositions, mechanical properties, fabrication steps, applications, benefits, and cautions about applying each material in any application & environment, you would need to study a book (or maybe take a course). People can help you select a stainless steel for your particular application, but they can't possibly condense books and years of experience into a paragraph :-)

Regards,

Well, here's a nice long-running thread with some unanswered posts going back a ways.

Chika:
Either is probably fine, though if anybody plans on using a chloride based cleaner on a regular basis (not uncommon with food equipment because bleach and similar chemicals are often viewed as the default sanitizer) then 316 might be better to have.

SK Sharma: 316 in marine environments, always.

Jack Ho: Either should be fine for potable water.

Ruthiraan Mani Maran: A grease trap? Probably either is fine.

Al Soco: Wastewater treatment plants are apparently pretty corrosive areas too, so I would stick to 316. If you just mean a wastewater stream from a manufacturing plant, it depends on what's in there. Always 316 for better chlorine resistance though.

Hi Elimo. They are available in 304SS as well as 316SS, so it is certainly possible and often done. But it is hard for people who don't know you, your product, or your expectations to predict whether you will be satisfied. I'd say try it :-)

Regards,

A. Hi Mike. You can always find one or more people who think any material of construction is "toxic", but stainless steel pots & pans of many different grades are routinely used for cooking in kitchens by tens of millions, maybe hundreds of millions, of people. 316SS heat deflectors will probably last forever. Good luck.

Regards,