304 and 316 stainless steels are two common austenitic stainless steels that have some significant differences in their chemical composition, properties, and applications:

1. Chemical composition
The main composition of 304 stainless steel is chromium (18%-20%), nickel (8%-10.5%), and trace elements include carbon content ≤0.08%, manganese ≤2%, silicon ≤1%, phosphorus ≤0.045%, sulfur ≤0.03%.
316 stainless steel is mainly composed of chromium (16%-18%), nickel (10%-14%), molybdenum (2%-3%), trace elements including carbon content ≤0.08%, manganese ≤2%, silicon ≤1%, phosphorus ≤0.045%, sulfur ≤0.03%. Compared with 304,316 stainless steel, it contains 2%-3% molybdenum, which gives it better corrosion resistance.

2. Corrosion resistance
304 stainless steel has good corrosion resistance in the ordinary environment, but the pitting resistance in the chloride environment (such as seawater, salt spray) is relatively weak, and corrosion is easy to occur.
316 stainless steel because of the molybdenum element, the resistance to chloride corrosion (pitting, crevice corrosion) is stronger, more suitable for highly corrosive environments, such as Marine and chemical processing equipment.

3. Mechanical properties
At room temperature, the strength and hardness of 304 and 316 are not different, and they have excellent toughness and ductility. In high temperature environment, the antioxidant performance of 316 is slightly higher than that of 304.

4. Cost
Because 316 contains molybdenum and a higher nickel content, it usually costs more than 304.

5. Application field
304 stainless steel is mostly used in daily life kitchen equipment, tableware, storage tanks, household appliances, etc., suitable for use in the general environment, cost-effective.
316 stainless steel is mostly used in fields requiring higher corrosion resistance, such as Marine equipment, medical devices, chemical equipment and the food industry, especially suitable for contact with salt water or strong acidic environments.

Sum up
If you need higher corrosion resistance (such as contact with salt water or chemical media), 316 stainless steel is more suitable; In the ordinary environment, 304 stainless steel is enough to meet the demand, while the cost is lower.

Gavin

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Gavin@huissmetal.com