Stainless steel is mainly known for its resistance to corrosion. That is why it has a variety of applications. Stainless steel is available in a diverse range of grades that let it accommodate different applications across a lot of industries. But, because there are many grades available, you need to know knowledge of how to choose the appropriate one for the job. This is important even if you choose to invest in surplus steel. When choosing a stainless steel grade, make sure you consider the following:
Formability of the Stainless Steel
If you want to use stainless steel for applications that require good formability, steer clear of the martensitic group of stainless steels. Instead, choose an austenitic grade like 304 or a ferritic grade like a 430. Often, austenitic stainless steel is the right choice in terms of formable stainless steels.
Welding stainless steel can result in issues like hot cracking, intergranular corrosion, and stress corrosion cracking. Typically, the austenitic group of stainless steels is the most weldable type. Make sure you to use grades like 304L or 347 when welding this type of stainless steels. This is because 304L tends to have lower carbon while 347 has niobium stabilizers added to it to help in deterring intergranular corrosion.
Although the majority of stainless steel grades can be machined, the metal is quite susceptible to work hardening. It is important to optimize the machining process to work at a rate which helps alleviate this problem. Also, use machining tools that are kept in good working condition. To increase the machinability of steel, sulfur can be added such as in the case of grade 303.
Level of Resistance to Corrosion
Usually, stainless steel is picked for its resistance to corrosion. However, you need to know that different grades offer different amounts of corrosion resistance. In general, austenitic stainless steel offers the most corrosion resistance due to the amounts of chromium. So, if your project requires a high level of corrosion resistance, choose grade 316. Martensitic and ferritic stainless steels are generally more affordable than austenitic stainless steel since they have less nickel and less chromium.
Ability to be Heat-Treated
If you will be heat treating the stainless steel, you must be aware of how this process can impact the different stainless steel grades. Usually, austenitic stainless steel and ferritic steels are non-hardenable when treated with heat. Typically, the heat treatable stainless steels are martensitic or precipitation hardened.