In this article, you will know the different grades of stainless steel as well as their properties and uses.
In our previous article, we learned about the different types of metals and their uses.
Metal can be classified into three categories which are: Ferrous Metal, Non-Ferrous Metal, and Alloys.
Stainless steel is a type of ferrous metal that comes under alloy steel which is a type of steel and grades of stainless steel made from different types of stainless steel such as austenitic, ferritic, martensitic, precipitation hardening, and duplex stainless steels.
So without wasting time let's get started.
What is Stainless Steel?
Stainless Steel is an alloy of iron, carbon, chromium, nickel, silicon, copper, etc.
If any steel has more than 10.5% of chromium then it is considered stainless steel.
Chromium forms as a thin layer of oxide on the surface of the steel
Due to its chromium content, it has excellent resistance to corrosion.
Increasing the amount of Chromium increases the corrosion resistance.
Elements Present in Stainless Steel
The following elements are present in stainless steel:
- Carbon
- Chromium
- Nickel
- Molybdenum
Carbon
Carbon provides strength but forms precipitates i.e harmful to corrosion resistance.
Chromium
Forms a surface film of chromium oxide to make it corrosion-resistant.
Nickel
Enhance ductile property.
Molybdenum
Increase corrosion resistance, and strength at the higher temperature.
Grades of Stainless Steel
There are more than 150 grades of stainless steel found here we have discussed only some of the commonly used stainless steel grades which are:
- Grade 100 Series
- Grade 200 Series
- Grade 300 Series
- Grade 400 Series
- Grade 500 Series
- Grade 600 Series
- Grade 2205
- Grade 2304
- Grade 2507
- Grade 17-4
- Grade 15-5
- Grade 904L
Grade 100 Series
It is an austenitic type of stainless steel mainly used in furniture making.
Grade 200 Series
Grade 200 series is austenitic type stainless steel which contains chromium, nickel, and manganese alloy which is used for general purposes such as metalwork.
In this 200 series the most popular two types of stainless steel grades are used:
- Grade 201
- Grade 202
Grade 201
Grade 201 stainless steel is an austenitic stainless steel containing 16 to 18% chromium and 3.5 to 5.5% nickel. Due to its low nickel content, it provides average protection against corrosion. However, it is cheaper than other stainless steels, and the concentration of manganese and nitrogen can be increased to improve its yield strength.
The versatility of grade 201 is due to its good formability and weldability.
Uses of Grade 201
This type of stainless steel grade is mostly used in making structural members, decorative materials, household items, utensils, windows, doors, automotive parts, cars, etc.
Grade 202
Grade 202 stainless steel is an austenitic stainless steel containing 17 to 19% chromium, 4 to 6% nickel, and 7.5 to 10% manganese. This type of grade is mostly used for precipitation hardening and it also has good corrosion resistance, high hardenability, strength, toughness, and weldability.
Uses of Grade 202
This type of stainless steel grade can be formed into sheets, coils, and plates that's why it is used in manufacturing household items, kitchenwares, structural members, automotive trim, hose clamps, etc.
Grade 300
300 Series is also an austenitic type of stainless steel that contains chromium, and nickel alloy.
This series of grades is used for food utensils, surgical scrub sinks, instruments, etc.
In this 300 series the most popular types of stainless steel grades are used which are:
- Grade 301
- Grade 301L
- Grade 301LN
- Grade 302
- Grade 304
- Grade 304L
- Grade 305
- Grade 309
- Grade 316
- Grade 316L
- Grade 316H
- Grade 321
- Grade 321H
- Grade 347
Grade 301
Grade 301 is an austenitic type of stainless steel that contains lower than 16 to 18% chromium due to this corrosion resistance low.
Grade 301 has high strength and is also available in annealed and cold-worked conditions.
Grade 301L
Grade 301L is a variant of Grade 301 with an improved version of ductility and weldability.
It requires no annealing for maximum corrosion resistance.
Grade 301LN
This is also another variant of 301 which contains higher nitrogen and has a higher work hardening rate.
There is also no need for annealing.
Uses of Grade 301, 301L and 301LN
Grades 301 and grade 301LN are used for making aircraft components, automobiles, cooking utensils, kitchenwares, wiper blade clips, etc. While Grade 301L is used in pressure vessels, door and drainage parts, appliances parts, etc.
Grade 302
Grade 302 is an austenitic type of stainless steel that contains up to 18% chromium and 8% nickel.
This type of grade has high toughness, tensile strength, yield strength, and also corrosion resistance.
It can be processed at low speeds and also high feed volumes to overcome their work-hardening tendencies.
In this grade, post-weld annealing must be performed.
Uses of Grade 302
Grade 302 is mostly used in food handling equipment and also for making cooking utensils, kitchenware, medical tools, etc.
Grade 304
Grade 304 is the most popular austenitic stainless steel which contains up to 18% chromium and 8% nickel.
So grade 304 is also known as grade 18/8.
It has high corrosion resistance in a wide range of temperatures.
But, it becomes susceptible to pitting corrosion and stress corrosion cracking when exposed to chlorides.
Grade 304L
It is a variant of grade 304 which has a lower carbon percentage than grade 304, thus giving it a higher corrosion resistance.
Uses of Grade 304 and 304L
Grade 304 and 304L are used to manufacture deep-drawn sinks, pans, pots, etc.
It is also used for making mechanical fasteners such as nuts, bolts, and screws.
Grade 305
It is an austenitic type of stainless steel that contains up to 18% chromium, and 10% nickel.
It has high corrosion resistance and strength.
It can be welded with resistance and fusion techniques.
Uses of Grade 305
It is used for making deep-drawn parts, pans, bowls, rivets, screws, etc.
Grade 309
It is a type of austenitic stainless steel that contains up to 22% chromium, 12% nickel, and some amount of carbon.
It possesses excellent corrosion as well as oxidation resistance, and high tensile and creeps strengths.
It can also withstand saline environments.
It can be rolled, formed, and deep drawn.
Uses of Grade 309
It is mostly used in the manufacturing of boilers, furnaces, ovens, heat exchangers, kilns, aircraft engines, etc.
Grade 316
This is the most popular and widely used next to grade 304.
Grade 316 contains elevated amounts of molybdenum and high amounts of silicon, manganese, carbon, chromium, and nickel.
High molybdenum concentration makes it more resistant to pitting and crevice corrosion as compared to grade 304 in saline environments.
It has good forming and welding characteristics.
In this type of grade, there is no need for annealing after welding thin sections.
Grade 316L
Grade 316L is the variant of Grade 316 which contains a minimum amount of carbon and is insusceptible to chromium carbide precipitation.
That's why this grade is preferred where heavy welding requires.
Grade 316H
Grade 316H is also a variant of Grade 316 that contains a higher amount of carbon which makes it have higher tensile and yield strength and is more suitable for high-temperature applications.
Uses of Grade 316, 316L, 316H
These grades are mostly used in the manufacturing of chemical storage tanks, heat exchangers, reactors, furnaces, and other process equipment, etc.
Grade 321
Grade 321 is a titanium-stabilized austenitic stainless steel.
when exposed to high temperatures it has excellent resistance to chromium carbide precipitation.
As compared to grade 304 it has high creep and stress rupture properties.
Grade 321H
It is a variant of grade 321 that contains high carbon content which makes its strength at higher temperatures.
Uses of Grade 321 and 321H
These grades are mostly used for making furnace parts, heat exchangers, and heating and chemical process equipment.
Grade 347
It is a niobium-stabilized austenitic stainless steel.
As compared to grade 304 It has higher creep and stress rupture properties.
It has better corrosion resistance and oxidation resistance than grade 321.
Uses of Grade 347
Grade 347 is commonly used for making aircraft and aerospace components, expansion joints, bellows, etc.
Grade 400 Series
It is a ferritic and martensitic chromium alloy series that contains some amount of stainless steel.
This grade is mostly used for car exhausts, cutlery steel, knives, etc.
In this 400 series the most popular types of stainless steel grades are used which are:
- Grade 409
- Grade 410
- Grade 420
- Grade 420HC
- Grade 420J2
- Grade 430
- Grade 434
- Grade 440
Grade 409
Grade 409 is a ferritic type of stainless steel that has the presence of titanium and niobium.
It has good corrosion resistance that is maintained at high temperatures.
It also has good formability and welding characteristics.
This type of grade can be welded by various methods such as arc, resistance spot, and seam welding.
Uses of Grade 409
Grade 409 is mostly used for making automotive exhaust systems along with also used for making fuel filters, heat exchangers, etc.
Grade 410
Grade 410 is a type of martensitic stainless steel that contains up to 11.5% chromium.
This type of grade is compatible with water, air, hot gases, food products, as well as most chemicals such as mild acids, nitric acid, concentrated sulfuric acid, etc.
Grade 420
Grade 420 is a type of martensitic stainless steel that contains 0.15 to 0.45% carbon and up to 12% chromium.
It has much lower corrosion resistance than austenitic and ferritic stainless steels but is sufficient to withstand mild acids, alkalis, freshwater, normal atmospheric conditions, etc.
It can be machined easily, but machinability decreases when increasing hardness.
Grade 420HC
Grade 420HC is a variant of grade 420 which contains a higher carbon content.
Due to its higher carbon content gives higher hardness than grade 420.
It has a lower corrosion resistance as compared to grade 420.
Grade 420J2
Grade 420J2 is also a variant of grade 420.
It can be annealed and is used to manufacture surgical instruments, daggers, swords, budget knives, etc.
Uses of Grade 420, 420HC, and 420J2
These grades are generally used for making cutlery, scissors, blades, etc. While grade 420 HC and 420 J2 are used for making economical knives and cutting tools.
Grade 430
Grade 430 is ferritic-type stainless steel which contains chromium iron, nickel, and some other alloying elements.
It has good corrosion resistance.
It has good machinability and formability characteristics as well as a low work hardening rate.
Uses of Grade 430
These grades are mostly used for making kitchen utensils, sinks, pipes, tubes, automotive trim, etc.
Grade 434
This is the most common type of ferritic stainless steel, which contains high molybdenum which increases its corrosion and heat resistance.
Uses of Grade 434
These are used in automotive trim, furnace chambers, range hoods, gas burners, chemical process equipment, etc.
Grade 440
It is a ferritic type of stainless steel that contains high carbon.
Due to the high carbon content, it has a higher hardness which makes it suitable for valve components and ball bearings.
Uses of Grade 440
These are used in valves, valve seats, ball bearings, etc.
Grade 500 Series
It is a heat-resistant chromium alloy series that's why it is also known as heat-resistant chromium alloy.
This grade contains a high amount of chromium that prevents deformation when it is exposed to heat.
Uses of Grade 500 Series
These grades are mostly used where a high amount of heat is a concern.
Grade 600 Series
It is a martensitic alloy series that is formed by precipitation hardening.
Uses of Grade 600 Series
These grades are mostly used in the thermal processing industry.
Grade 2205
It is a duplex type of stainless steel that has excellent strength and corrosion resistance.
Uses of Grade 2205
These grades are mostly used in oil and gas, petrochemical, marine, etc.
Grade 2304
It is a duplex type of stainless steel that is almost similar to grade 2205.
Uses of Grade 2304
This grade is most suitable for use where the temperature ranges from 58°F to 572°F.
Grade 2507
It is a duplex type of stainless steel that has high thermal conductivity, strong chloride stress corrosion resistance, and also has a low coefficient of thermal expansion.
It has excellent corrosion resistance and strong tensile strength.
Use of Grade 2507
These grades are commonly used in petrochemical equipment, mechanical and structural components, etc.
Grade 17-4
It is a type of precipitation-hardening stainless steel that has both high strength and corrosion resistance.
Its degree of strength can be manipulated through heat treatment.
Uses of Grade 17-4
These grades are commonly used in the aerospace, petroleum, and chemical industries.
Grade 15-5
It is a type of precipitation-hardening stainless steel that has high strength and corrosion resistance.
This type of grade is only suitable for hot working.
Uses of Grade 15-5
These grades are mostly used in high-pressure, corrosive environments and aerospace industries.
Grade 904L
It contains 0.02% C, 19 to 23% Cr, 23 to 28% Ni and 4 to 5% Mo.
Use of Grade 904L
These grades are mostly used in the chemical process industry where high corrosion resistance is required.
So here you have to know all aspects related to grades of stainless steel.
If you have any doubts then you are free to ask me by mail or on the contact us page.
Thank You.
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