hoser said:
Perhaps "lesser grade" wasn't most accurate but for purposes of this thread, 400 series stainless steel has less rust resistance than 300 series SS and therefore it is LESS desirable for grills. Keepin' it simple. Non-magnetic=good for grill use. Magnetic=bad for grill use. Of course, there are also other factors such as material thickness and finish.
Hoser, I'm flaming the grill companies here, not you. The grill companies have good marketing material to sell their grills; but they are not always truthful, and they put a lot of mis-information out there. As stated before, the difference between the 304 & 430 is not measurable, for this application. I don't want folks to run away from a good stove or grill, because it is made from 430, and not 304 SS.
More important issues would be: Did they heat treat it after welding. If not, there is a high possibility of corrosion along the heat-affeced zone (HAZ). The corrosion properties of the SS are modified in the HAZ.
Here is more info on the 304 & 430 series SS. Both of these SS grades are used in the food industry, for different purposes.
Check out the info on 304 & 430. The others are just FYI.
Type 304
The
most common of austenitic grades, containing approximately 18% chromium and 8% nickel. It is used for chemical processing equipment, for
food, dairy, and beverage industries, for heat exchangers, and for the milder chemicals.
Type 316
Contains 16% to 18% chromium and 11% to 14% nickel. It also has molybdenum added to the nickel and chrome of the 304. The molybdenum is used to control pit type attack. Type 316 is used in chemical processing, the pulp and paper industry, for food and beverage processing and dispensing and in the more corrosive environments. The molybdenum must be a minimum of 2%.
Type 317
Contains a higher percentage of molybdenum than 316 for highly corrosive environments. It must have a minimum of 3% “moly”. It is often used in stacks which contain scrubbers.
Type 317L
Restricts maximum carbon content to 0.030% max. and silicon to 0.75% max. for extra corrosion resistance.
Type 317LM
Requires molybdenum content of 4.00% min.
Type 317LMN
Requires molybdenum content of 4.00% min. and nitrogen of .15% min.
Type 321
Type 347
These types have been developed for corrosive resistance for repeated intermittent exposure to temperature above 800 degrees F. Type 321 is made by the addition of titanium and Type 347 is made by the addition of tantalum/columbium. These grades are primarily used in the aircraft industry.
Type 430
The
basic ferritic grade, with a
little less corrosion resistance than Type 304. This type combines
high resistance to such corrosives as nitric acid, sulfur gases, and many organic and
food acids.
Type 405
Has lower chromium and added aluminum to prevent hardening when cooled from high temperatures. Typical applications include heat exchangers.
Type 409
Contains the lowest chromium content of all stainless steels and is also the least expensive. Originally designed for muffler stock and also used for exterior parts in non-critical corrosive environments.
Type 434
Has molybdenum added for improved corrosion resistance. Typical applications include automotive trim and fasteners.
Type 436
Type 436 has columbium added for corrosion and heat resistance. Typical applications include deep-drawn parts.
Type 442
Has increased chromium to improve scaling resistance. Typical applications include furnace and heater parts.
Type 446
Contains even more chromium added to further improve corrosion and scaling resistance at high temperatures. Especially good for oxidation resistance in sulfuric atmospheres.