7 things to consider when choosing stainless steel
Stainless steel is widely used mainly for its corrosion resistance. However, there are many grades of stainless steel, and their formability, strength, and workability vary. Different grades make it suitable for various applications in many different industries. However, having so many grades of stainless steel requires expertise to choose the right grade for the job.
When choosing a stainless steel grade, the following 7 points need to be considered:
Does it need to have good formability?
Do you need welding?
Need processing?
How many types of corrosion are required?
Need heat treatment?
What are the strength requirements?
What are the typical applications?
Does stainless steel need to have good formability?
If the application requires good formability, avoid using martensitic stainless steel. Try using austenitic stainless steel (eg 304) or ferritic stainless steel (eg 430).
Does stainless steel need to be welded?
Welded stainless steel is very different from welded carbon steel, which may cause intergranular corrosion, thermal cracking and stress corrosion cracking. The stainless steels that are most easily welded usually belong to the austenitic group.
Do you need to process stainless steel?
If machining is required, special care must be taken when using stainless steel. Most grades of stainless steel can be processed, but stainless steel is easy to work harden. The machining process must be optimized to work at a rate that helps alleviate this problem, and the tools used for machining must also maintain good working conditions.
How many types of corrosion are required?
Stainless steel is usually selected because of its corrosion resistance, but it is important to know that different grades of stainless steel provide different amounts of corrosion resistance. Austenitic stainless steels generally have the highest corrosion resistance because they contain large amounts of chromium. When corrosion resistance is important, this makes grade 304 an excellent choice.
Does stainless steel need heat treatment?
If you want to heat treat stainless steel, it is important to know how to affect various grades of stainless steel. To a large extent, austenitic and ferritic stainless steels are not hardenable after heat treatment.
What are the strength requirements for stainless steel?
Martensitic stainless steel can reach very high strength, such as 440C grade. And precipitation hardening stainless steel, such as 17-4 PH and 15-5 PH grade. Austenitic stainless steel (eg 316 grade) can also provide high strength, although not as high as martensite grade.
typical application Sometimes, the best way to find out which grade of stainless steel should be used is to check the stainless steel used in the past. The following are some examples of the use of certain grades of stainless steel.
Ferritic stainless steel:
Class 409: Automotive exhaust system and heat exchanger
Class 416: shafts, shafts and fasteners
Class 430: Food industry and electrical appliances
Class 439: Automotive exhaust system components Austenitic stainless steel:
Class 303: fasteners, accessories, gears Grade
304: general-purpose austenitic stainless steel
Class 304L: Class 304 applications requiring welding
Class 309: Applications involving high temperatures
Class 316: Chemical applications
Class 316L: Class 316 applications requiring welding Martensitic stainless steel:
Class 410: Renewable martensitic stainless steel
Class 440C: bearings, tools and other wear-resistant applications Precipitation hardening stainless steel: 17-4 PH: Aerospace, Nuclear and Chemical Applications
15-5 PH：Valves, fittings and fasteners
Duplex stainless steel: 2205: Heat exchanger and pressure vessel 2507: Pressure vessel and desalination plant