304 material composition is OCr18Ni9; 316 material composition is 0Cr17Ni12Mo2
The most important difference between 304 and 316 is that 316 has 2-3 more nickel than 304 and 2% more MO (molybdenum).
First of all, 316 stainless steel contains Mo, which has better corrosion resistance in high temperature environment than 304 stainless steel. Therefore, in high temperature environment, engineers generally choose 316 material parts.
Secondly, 316 mainly reduces the Cr content, increases the Ni content, and increases Mo2% ~ 3%. Therefore, its corrosion resistance is stronger than 304, which is suitable for use in chemical, seawater and other environments. Similarly, 316 cost is higher than 304. Generally, 316 is used in places with higher requirements instead of 304.
The 316L steel grade adds molybdenum to 304, which can significantly improve its ability to resist intergranular corrosion, oxide stress corrosion, and reduce the tendency of hot cracking during welding. It also has good resistance to chloride corrosion. Commonly used It is used in places with high sanitary requirements and strong media corrosion performance, such as pure water, distilled water, medicines, sauces, and vinegar.
304 is better than 316 in mechanical properties. Because of its corrosion resistance and outstanding heat resistance, 304 is widely used as a stainless heat-resistant steel. 304 and 316 have similar strength and hardness.
Difference: The corrosion resistance of 316 is much better than that of 304. The more critical point is that the addition of molybdenum metal to 316 has improved the heat resistance.
The Ni-Mo alloy has excellent corrosion resistance. In heavily polluted industrial areas and coastal areas, the surface can be very dirty and even rusty. However, to achieve aesthetic effects in outdoor environments, nickel-containing stainless steel is required. Therefore, 304 stainless steel is widely used in curtain walls, side walls, roofs and other building applications, but in severely corrosive industrial or marine atmospheres, it is best to use 316 stainless steel. 304 18cr-8ni-0.08c has good corrosion resistance, oxidation resistance and processability, strong acid resistance, can be stamped, and can be used to make containers, tableware, metal furniture, building decoration, and medical appliances.
316 18cr-12ni-2.5Mo improves the corrosion resistance to chemical hydrochloric acid and the ocean, and improves the corrosion resistance to brine halogen solutions, which can be used in seaside buildings, ships, nuclear electrochemistry and food equipment, etc.
304 stainless steel has good comprehensive properties and has been widely used. Although 316 stainless steel is not as widely used as 304 stainless steel, it has also been widely used in places with high requirements for corrosion protection, especially in the shipbuilding industry. That is, the performance of the two is close, but the corrosion resistance of 316 stainless steel is higher.
304 stainless steel is a versatile stainless steel material. High temperature resistance is also good, and the general temperature limit is less than 650 ° C. 304 stainless steel has excellent stainless corrosion resistance and good resistance to intergranular corrosion.
316 stainless steel, 18Cr-12Ni-2.5Mo Due to the addition of Mo, its corrosion resistance, atmospheric corrosion resistance and high temperature strength are particularly good, which can be used under harsh conditions; excellent work hardening (non-magnetic). From an economic perspective, 304 is better than 316; under strong acid or alkaline environment, 316 is better than 304.