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What is the difference between AISI 430 and AISI 304-2B??Helpful Member!(3) 

cocina (Industrial)
19 Apr 11 2:19
I am designing my kitchen for my restaurant and i have 2 different qoutes from different companies of stainless steel fabrication companies for equipment such as benches, shelving, stoves and deep fryers. One company uses AISI 430 and the other uses AISI 304-2b. What is the difference? Is one clearly better than the other for these types of aplications? Thankyou for your help in advance!
Helpful Member!  JamesCKelly (Materials)
19 Apr 11 10:25
430 is a ferritic stainless with nominal 16.5% chromium. It is magnetic, so if that matters to you one can hang magnetic refrigerator notes on it.

304 is an austenitic stainless, nominal 18% chromium 8% nickel. It is non-magnetic, mostly, and forms better. Is more costly,because of that 8% nickel, and also more corrosion resistant.

The metallurgy is all very interesting but what I would suggest you need is comments from other restaurant guys as to what they use & how it actually works out for them (if they can hang a magnet on a flat area, it is 430).  
EdStainless (Materials)
20 Apr 11 9:11
The 430 is usually stronger/harder.
My concern is for place where they have welded.  The 430 would be more susceptible to local corrosion in these areas.

The 2b suffix is the surface finish, in this case a bright rolled finish.

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Plymouth Tube

Helpful Member!  vthomidis (Mechanical)
20 Apr 11 9:23
AISI 430 should less costly than 304-2b.

As jamescKelly pointed out 430 is the so called "ferritic" quality – it is magnetic, if that's a concern to you.

AISI 304 is "austenitic" – practically not magnetical.

An issue which may be important to you is the 2b spec.
This means that the surface of the 304 is smooth not reflective with good flatness.
These properties are not guaranteed in 430.

 Another important thing which you should verify with fabricators is if 430 is adequate for being in contact with "food" since fabrication of a deep fryer is
Included.
( I am 95% certain it is OK but a confirmation would be better ).
 
dgallup (Automotive)
20 Apr 11 13:51
I think most industrial food prep uses 316 stainless which is more corrosion resistant (& more expensive) than either 304 or 430.  I would question 430 for food use.
EdStainless (Materials)
21 Apr 11 19:30
There is little 316 used in kitchen and prep equipment.
You see 316 used in food processing (production) applications.
Though these are being replaced with lean duplex grades now.  Very little new 316 is going into piping systems.

There is a lot of 430 used.  In utensils and equipment, though much of the fabricated stuff is actually 439 because it is more weldable.
 

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Plymouth Tube

Helpful Member!  mcguire (Materials)
7 May 11 23:20
cocina

I have worked with restaurant equipment producers for many years. You can use 430 without corrosion problems ONLY if it is bright-annealed. DO NOT use 430 in 2B or #4 polish. It will corrode. Use it only in Koolline or similar finish.

304 is tolerant of any kitchen use, as long as you keep it rinsed of chlorides, such as found in cleaners and coastal environments. 316 is never needed except for special equipment.

Smarter producers use 201 instead of 304 and that saves at least 10% in material cost.

Post the type of equipment and I'll tell you who the better producers are.

Michael McGuire
http://stainlesssteelforengineers.blogspot.com/

cocina (Industrial)
4 Aug 11 1:16
Thankyou for all the replies! It turns out that 304 2b is what is commonly use in kitchens. There are alot of dodgey companies here in Peru where I am living, using cheaper materials.

I have a new question. In the kitchen I have a walk in refrigerator. I have been quoted to have shelving put in of the following specs:

04 Tableros en plancha de
Acero Inoxidable AISI 304 2B - de 1/20" reforzados. Cuatro
parantes verticales de tubo cuadrado de 1" x 1" x 1.5mm,
de Acero inoxidable con pernos de regulación de altura.

But since then my girlfriend has been told by 2 chefs that she studies with that stainless steel shelving is no good in coolrooms and that it will be rusty in 2 years. I find it hard to believe. They have told her that epoxy coated steel shelving is better. But i recall seeing epoxy coated shelving cracking and corroding away. I am hoping that they are confused with galvanised shelving and that the stainless steel shelving i have ordered to be made is ok.....

Your thoughts would be apreciated!

Confused Chef
mcguire (Materials)
5 Aug 11 9:36
The information given to your girlfriend is wrong. Stainless will not corrode if kept clean. period.

The other chefs probably kept steel containers on the shelves and let them sit and rust, staining the stainless surface. If this happens, simply clean off the rust stains with scouring powder and the surface is good as new.
 

Michael McGuire
http://stainlesssteelforengineers.blogspot.com/

arunmrao (Materials)
5 Aug 11 9:40
I have a stainless steel refrigerator ,for the past 5 years,and there are no signs of any corrosion or rust stains. The information provided to you is not right.

_____________________________________
"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year

EdStainless (Materials)
5 Aug 11 22:03
The other cause for rusting is that people clean with acidic or chloride cleaners and then leave them wet with residue.
If you want to corrode a hole in a SS sink you put a glop of liquid soap on it and don't rinse.  It will take a week or so to corrode a ring of pits.

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Plymouth Tube

dgallup (Automotive)
9 Aug 11 18:44
I don't buy that Ed.

I just came home from 3 weeks vacation and the soap dispenser (containing liquid Dawn detergent) had pumped a nice puddle of dish cleaning liquid on the rim of my stainless steel sink.  Thermal expansion I suppose as I had set the thermostat quite a few degrees higher while away & we had some 100+ degree days.  It was well dried and aged.  Wiped it up with a wet sponge.  No pits.

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
 

CalvinKelly (Materials)
9 Aug 11 19:09
I agree with Ed.

Try using "Lemon Jxx", or some other soap with implied orange/lemon/whatevercitric acid. The dishwasher soap used by my wife sometime in the last decade made some deep, deep pits under white deposits on my 18-10 flatware when the washed dishes were left unattended (in an older dishwasher).

Know a guy who makes (has the Chinese make) those stainless containers for hand soap, found in some hotels. His opinion was he could not be guaranteed the Chinese would use his choice of (pitting resistant) stainless so he has them lined with plastic.
Whatever one thinks of his solution, he has a real problem with liquid hand soaps corroding his pretty stainless bottles.

Kinda off-topic. In food preparation the problem is most likely to arise from disinfecting by use of Chlorox. Sodium hypochlorite will eat the hell out of any stainless, if left alone & not well rinsed. Solution is rinsing, not spending the federal deficit on more resistant stainless.

James Kelly
www.rolledalloys.com

btrueblood (Mechanical)
9 Aug 11 20:31
The trend towards "antibacterial" soaps is eating up stainless too, as most of the active agents in those soaps are high-chlorine content chemicals, e.g. TriCloSan.
EdStainless (Materials)
9 Aug 11 23:28
The way that they control the viscosity of gel soaps is to make them thin and then add salt to get the correct viscosity. that way every batch looks the same.  I have seen a few % Cl in these soaps.
If the puddle of soap starts to dry out the edges will concentrate.  I have seen this in kitchens and in labware.

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Plymouth Tube

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