439 Stainless Steel Vs 316

The choice of stainless steel grade 301 for suburban rail cars ensures that the basic vehicle will survive without structural rust for the required life measured in decades.

439 stainless steel vs 316.

Stainless steel is not a single alloy but rather the name applies to a group of iron based alloys containing a minimum of 10 5 chromium. These two types of stainless steel are categorized by their microstructure. Stainless 304 usually consists of 18 chromium and 8 nickel. This designation is related to the microstructure of the metal the differences can be seen under an electron microscope in this picture a is austenitic 304 and b is ferritic 430.

This reduces pitting from chemical environments and allows grade 316 stainless steel to be used in highly acidic and caustic environments that would otherwise eat away at the metal. Type 439 is an 18 chromium titanium stabilized ferritic stainless steel with corrosion resistance similar to that of 304 304l stainless steel. The ak steel 439 ultra form stainless steel samples at 1700 f 926 c gained 320 mg in 2 after 1000 cycles but were not determined as catastrophic failures. 316l is an austenitic stainless steel and 439 is a ferritic stainless steel.

Stainless 316 contains more nickel than stainless 304 while 304 contains more chromium than 316. Molybdenum is a chemical element used for the strengthening and hardening of steel. Other elements are added and the chromium content increased to improve the corrosion resistance and heat resisting properties enhance mechanical properties and or improve fabricating characteristics. Its main function in stainless 316 is to help fight off corrosion from chlorides.

The simple answer is 304 contains 18 chromium and 8 nickel while 316 contains 16 chromium 10 nickel and 2 molybdenum. 409 stainless steel will rust on the surface. This grade may be used in the annealed cold formed or as welded condition in applications where other stainless steels such as type 304 304l and type 430 are used. It is strong and will last 8 10 years in a moderate climate.

Stainless steel is more likely to crack due to this internal stress. Ak steel 11 cr cb stainless steel and aluminized type 409 data are shown for comparison. Due to the addition of molybdenum grade 316 stainless steel is more corrosion resistant than similar alloys such as 304 stainless steel. 201 201ln 301 304 304l 316 316l 409 410 430 439 441 just as there is a range of structural and engineering carbon steels ref.

The stainless panels will be cleanable will require no painting and the grade form ability machin ability weld ability 303 1 8 1 304 8 5 8 316 8 5 8 444 6 5 5 416 1. However this is not a concern for most people because it is hidden under the vehicle. Most modern factory exhaust systems are made from 409 stainless steel. The molybdenum is added to help resist corrosion to chlorides like sea water and de icing salts.