304 steel – advantages, properties, applications
AISI 304 stainless steel designates the first commercially available stainless steel grade. It belongs to the group of V2A steels, under which chromium nickel steel grades are summarized. It is the main representative of this group, and in some cases the terms 304 and V2A are also used synonymously. In European norm, it is specified under the number 1.4301. Its alloy code is X5CrNi18-10. It is known for its combination of corrosion resistance and good mechanical properties. It belongs to the group of austenitic steel grades.
Furthermore, it is the most widely used stainless steel alloy in the world today, accounting for one-third of total production.
Properties of 304 stainless steel
304 is characterized by its good weldability with electrical processes. Even without heat treatment, the steel is corrosion resistant, due to its low carbon content. For maximum corrosion resistance, however, post-weld treatment may be required. The carbon content must be below a percentage of 0.08, although values below 0.05% are now common in practice. It also has very good polishability and can be flexibly shaped. It is approved for temperature stresses up to 600 °C. Its high-quality appearance is also appreciated, especially in the polished state.
Variations of 304-grade stainless steel
304 is characterized by a chemical composition of 18 % of chromium, a nickel content of 8 %, and a maximum of 0.08 % of carbon. Variations of this grade differ in the amount of carbon.
304L
304L is the low carbon version of 304 and is restricted to a maximum of 0.03 % of carbon. This alloy does not need post-weld annealing. The material 304L is easy to polish and deep-draw. It is mainly used in the chemical, petroleum, petrochemical and automotive industries and for heavy gauge components.
304H
304H is characterized by a higher carbon content between 0.04 and 0.1 %. Therefore, it retains its strength at elevated temperatures. Further, it retains aqueous corrosion resistance at temperatures between 500° C and up to 800° C.
Applications of 304
304 has a wide range of applications. It is particularly useful when resistance in environments such as water, moisture or weak acids is required. It is used, among other things, in the construction of fittings, food industry, pharmaceutical industry or in mechanical engineering. Typical products for end consumers are, for example, pots or sinks.
Hardening of 304
304 is a versatile product, but it also reaches its limits in certain applications. Among other things, its intrinsically positive property of polishability can also manifest itself in a tendency to cold welding. One solution in this case is the BORINOX® process. With this process, the steel can be hardened and its susceptibility to cold welding is reduced. The BORINOX® process is also characterized by the fact that the positive properties, such as corrosion resistance, are retained while the hardness is increased.
In principle, hardening processes are often suitable for 304, as this steel is a relatively soft grade. If they need an increase in scratch resistance, the BORINOX® process can help produce it.
