Though stainless steels have similar characteristics, knowing the various types and grades available is crucial when reading a stainless steel grades chart.
This is particularly true if you want to look for the optimal price point and traits for your needs.
Because of its low price, strength, and flexibility, production of stainless steel keeps on increasing around the globe every year.
However, stainless steel is not a single alloy. It gets a huge part of its corrosion-resistant feature from chromium but both chrome and stainless steel are different substances. There are tons of combinations of different metals marketed as stainless steel.
When working with stainless steel, figuring out the correct alloy for your product is one of the first steps in determining the ideal options.
Breaking Down the Stainless Steel Grades Chart
Professionals categorized stainless steel into classes. There are three common types of stainless steel. This includes Austenitic, Ferritic, and Martensitic.
Austenitic Stainless Steel
Austenitic steels primarily exist in the 200 and 300 series. Thanks to their amazing corrosion resistance and formability, they’re the most specified stainless steel grades.
For those who don’t know, the most popular and commonly utilized stainless steel is the Grade 304 SS, which belongs to the Austenitic Stainless Steel group.
Austenitic stainless steels contain 2% to 20% nickel and 15% to 30% chromium. This allows for better workability, wear and corrosion resistance, and better surface quality.
When annealed, they are nonmagnetic. However, they can become a bit magnetic when cold-worked. This depends on the nickel content and other composition factors.
You might notice “H” or “L” attached to a couple of the grades. “H” means high carbon content. This is a sign of improved strength.
On the other hand, “L” means low carbon content. This means improved corrosion resistance.
201
Grade 201 is one of the Austenitic stainless steel. It has high work hardening and low nickel. They’re mainly used for hose clamps and cookware.
301
This is another Austenitic stainless steel. It has a combination of ductility and strength to endure severe forming methods. Its corrosion resistance is almost the same as 302.
They’re mainly used for car parts and rail cars.
302
Another Austenitic stainless steel is grade 302. It has high hardness and strength and great corrosion resistance.
It’s mainly used in pressure applications, cryogenic, sanitary, and food and drink.
303
303 grade is another Austenitic stainless steel in the stainless steel chart grades. The addition of selenium or sulfur offers its best machinability of all austenitic grades.
Unfortunately, it has lower corrosion resistance than 304. It’s mainly used in bushings, gears, aircraft fittings, bolts, and nuts.
304 (304L and 304H)
This stainless steel is a bit magnetic when cold-worked. It has great corrosion resistance. However, it’s vulnerable to pitting corrosion in warm chloride environments. It’s also tough.
Grade 304 accounts for more than 50% of all stainless steel manufactured around the world. It’s the most popular grades of stainless steel out there. It’s mainly used for food processing, kitchens, and architecture. These types of stainless steel strips are also used in interior decoration to achieve a luxury appeal.
309S
This stainless steel is great against oxidation. Thus, it’s mainly used in furnace components and other heating materials.
306 (306L and 306H)
Grade 306 has similar physical and mechanical properties as 304. However, it’s more resistant to pitting corrosion. This is particularly true in warm chloride environments.
It’s almost non-magnetic. It’s mainly used in hot water systems, food processing, and marine architectural parts.
317L
Compared to 316, grade 317L has better corrosion resistance. 317L is simply a variation of 317 appropriate for heavy-gauge welding.
It’s used in acetic acid distillation, dying and ink processes, paper, and pulp machinery.
321
This is another austenitic stainless steel. It’s stabilized using titanium. Thus, it is mainly used in heat exchangers and aircraft.
904L
This is another austenitic stainless steel when looking at the chart for grades. Experts consider this a “Super Austenitic” grade with excellent corrosion resistance, particularly to strong chlorides and acids.
This stainless steel grades steel is mainly used in sulfuric acid service.
Ferritic Stainless Steel
Another type of stainless steel that you’ll find in a stainless steel grades chart is Ferritic stainless steel. This group contains the 400-series steel.
Usually, they contain 10% to 20% chromium for resistance to scaling at high temperatures and corrosion protection.
Treating these metals with heat will not harden them. Also, they are magnetic. They have low carbon content. These stainless steels are mainly utilized on occasions where corrosion resistance is vital.
Ferritic stainless steel is ideal for welding due to its heat resistance and formability.
400
The first grade of the Ferritic stainless steel family is grade 400. Its corrosion resistance is almost the same as 409. However, it has a better surface finish.
It’s mainly used in applications that need a better finish than 409, such as caskets.
409 (Aluminized 409)
Another Ferritic stainless steel is grade 409. It’s resistant to car exhaust gas corrosion and atmospheric corrosion.
The aluminized version adds cosmetic and salt corrosion resistance. It’s mainly used in furnace liners, heat exchangers, and car exhaust systems.
430 (430F)
This is another Ferritic stainless steel. It has an excellent combination of mechanical properties, formability, and corrosion resistance.
430F is appropriate for high-speed machining. Unfortunately, it has low corrosion resistance. It’s mainly used in cold-headed fasteners, element supports, fridge doors, and car trim.
434
The use of molybdenum in this stainless steel grade boosts its pitting resistance. Thus, it is mainly used in car trim parts.
435 Mod
Another Ferritic stainless steel is the grade 435 Mod. It has improved weldability and formability. It’s used in car trims.
436
This Ferritic stainless steel is also used in car trims. It has excellent controlled roping.
439
Another Ferritic stainless steel. It is stabilized with Titanium. It has low carbon content with 18% chrome alloy.
Its resistance to corrosion varies on the environment. However, it’s great against pitting corrosion.
It’s mainly used in consumer appliances, chemical processing, power generation, cars, and nuclear applications.
444
It’s resistant to stress cracking, corrosion, and oxidation. It is mainly used in engine parts, water heaters, and installing solar panels on slate roofs.
2205
This stainless steel is around 50% austenitic and 50% ferritic. It has excellent durability and strength. It’s resistant to cracking, stress corrosion, fatigue, erosion, and crevice corrosion.
It’s used in petrochemical, chemical, and marine industries.
41003
It has great fabricating properties, toughness, and weldability. It is mainly used for tubing for bus frames, shipping containers, storage tanks, chutes, and hopper cars.
UR52N
This is a “Super Duplex” grade in the stainless steel grades chart with excellent resistance to sulfides and hot chlorides. It has great strength.
Professionals use it in petrochemical, chemical, and marine industries.
Martensitic Stainless Steel
This stainless steel type in the stainless steel grades chart is perhaps the least known stainless steel type. Just like Ferritic, they belong in the 400 series.
Typically, they contain 11% to 18% chromium. They also have higher levels of carbon compared to their ferritic counterparts.
With its amazing resistance to heat, these steels can lead to a huge variety of useful strength levels and hardness.
410 (410H)
This steel resists hot gasses, steam, mild alkalis and acids, freshwater, and a dry atmosphere. For ideal corrosion and heat resistance, they need to be hardened.
The 410H version has better hardenability. They’re used in cold heading, rulers, cutlery, mine ladder rungs, turbine components, shafts, pump components, screws, nuts, and bolts.
420 (420HC)
It has excellent resistance in hardened conditions to the atmosphere. HC provides better hardenability. It also has a higher-carbon grade.
It’s mainly used in needle valves, hospital equipment, and cutlery.
431
It has great resistance to a huge range of corrosive media. It’s almost the same as 304. However, it has high torque and tensile strength.
It’s mainly used in boat and pump shafts, marine hardware, bolts, and nuts.
440
It has moderate corrosion resistance, high carbon, excellent hardness, and strength. Experts use this in dies, gauge blocks, ball bearings, and knives.
FAQs
Which Is the Best Grade of Stainless Steel?
When looking for the best grade in the stainless steel grades chart, 304 stainless steel is the most common form of stainless steel utilized around the world.
The reason for this is that it has great value and corrosion resistance. The grade 304 can endure corrosion from most oxidizing acids.
This durability makes 304 easy to clean. Thus, they’re best for food and kitchen applications.
Which Is Better SS 304 Or 316?
You might be wondering if SS 304 is better than the SS 316 in the stainless steel grades chart.
While the stainless steel 304 alloy has a higher melting point, grade 316 has better resistance to chlorides and chemicals compared to 304.
This means that the stainless steel grade 316 is considered better when it comes to applications with exposure to salt or chlorinated solutions.
Which Stainless Steel Will Rust?
When it comes to stainless steel, chromium has the highest influence on rust resistance. This means that stainless steel alloys that are rich in chromium usually have better overall resistance to rust.
How Do You Stop Stainless Steel from Rusting?
Care and cleaning maintenance is a vital part of preventing your stainless steel tools from rusting. Usually, rust and corrosion are a result of the passivity film shield corroding due to chlorides, water deposits, scratches, and scrapes.
Will 304 Stainless Steel Rust Outside?
People usually think that rusting is impossible with stainless steel. Though it provides the most corrosion resistance than other alloys, the truth is that it can still rust in particular conditions.
While 304 stainless steel can corrode, it won’t rust in normal situations. The corrosion of stainless steel only happens under more aggressive conditions.
