The main difference is in corrosion resistance, stability toughness, thermal conductivity, and mechanical properties, as well as different fields of use and different applications.
Different performance
Corrosion resistance: 430 stainless steel contains 16.00-18.00% chromium. Basically doesn’t have any nickel metal. But 304 stainless steel contains more chromium and nickel metal. So the corrosion resistance of 430 stainless steel isn’t as good as that of 304 stainless steel.
Stability performance: 430 stainless steel is in the form of ferrite, and 304 stainless steel is in the form of austenite. So 304 stainless steel is more stable than 430 stainless steel.
Toughness：304 stainless steel is stronger than 430 stainless steel.
Thermal conductivity: The ferrite of 430 stainless steel has better thermal conductivity than the austenite of 304 stainless steel.
Mechanical properties. 430 stainless steel has added stable chemical elements, and the mechanical properties of the weld are better than 304 stainless steel.
Different application
430 stainless steel is mainly used for architectural decoration, fuel burner parts, household appliances, and home appliance parts. Added easy-cutting performance 430F steel to the 430 steel which is mainly used for automatic lathes, bolts, nuts, etc. Add Ti or Nb to 430 steel, and reduce the C content to 430LX, which improves the processing performance and welding performance. Mainly used for hot water tanks, hot water supply systems, sanitary appliances, household durable appliances, bicycle flywheels, etc.
304 stainless steel has the characteristics of high-temperature resistance, good processing performance, and high toughness which is widely used in industry, furniture decoration industry and the food and medical industry. 304 stainless steel also has strong corrosion resistance and is widely used in the production of equipment and parts that require good overall performance (corrosion resistance and formability).
Different applicable environment
The original intention of the research and development of 304 stainless steel is obviously inclined to be used in harsher environments, such as coastal areas, cold and humid places, and places with high acidity and alkalinity in the air, etc. It is more people-oriented and more considerate about the health of customers or the sense of use for customers.
However, 430 stainless steel has excellent heat resistance performance which is mainly used in places with higher temperature environmental conditions, such as boilers, hot water tanks, etc. It not only can prevent rust and corrosion but also has heat and high-temperature resistance. That is the real purpose of 430 ferrites stainless steel.