A magnet may or may not stick to 304 stainless steel. In the annealed condition, 304 is austenitic and non-magnetic. However, cold-worked 304 (drawn wire, tubing, bars after cold processing) often develops deformation-induced martensite and shows measurable magnetism. The degree varies by temper and amount of cold work.

Grade 316L is generally considered the healthiest food-contact stainless steel for cookware because of its superior corrosion resistance in acidic foods. Grade 304 is also approved for food contact and is used in the vast majority of food equipment. Both are safe; 316L provides an additional margin in acidic food environments.

XRF testing is the only reliable field method. Visually, 304 and 316 are indistinguishable. Check mill certifications (CMTRs) for the grade designation and heat number. Stainless Shapes provides CMTRs with all orders confirming exact chemistry.

Yes, Grade 316L has better corrosion resistance than 304 due to molybdenum. Grade 317L (higher molybdenum), duplex 2205, and super-austenitic grades (904L, 254 SMO) all surpass 304. Precipitation-hardening grades (17-4 PH) offer far superior strength.

In terms of mechanical strength, 304 and Grade 8 bolts are roughly comparable in tensile strength at room temperature (~120-150 ksi for Grade 8, ~75-90 ksi annealed for 304). Grade 8 is actually stronger in tensile/proof load. However, 304 is far more corrosion-resistant than Grade 8 carbon steel in aggressive environments.

Grade 316 is more expensive than 304 -- typically 20-40% more depending on form and market conditions -- due to its molybdenum and higher nickel content.

Among standard grades, duplex 2205, super-austenitic (904L), and nickel alloys (Inconel, Monel) offer higher corrosion resistance than 304. The highest grade depends on the environment.

Grade 304 stainless steel, if properly maintained in appropriate environments, can last for decades to a lifetime. In indoor food processing, pharmaceutical, and architectural applications, service lives of 30-50+ years are common. Exposure to chlorides or aggressive acids will shorten service life if 304 is used where 316 should be specified.

Grade 316 is the best standard stainless steel for avoiding rust in challenging environments. For indoor, mildly corrosive, or dry environments, 304 is entirely rust-free in service. The key is matching the grade to the environment.