Stainless Steel 304
Stainless steel grade 304 is an austenite stainless steel that is the most widely used and versatile of the various grades of stainless steel. It is a part of the T300 series stainless steels with...
Stainless Steel Series 400: Forms, Uses and Grades
Introduction
Describes uses for stainless steel series 400 grades 410, 416, and 420, how they are made, and where to purchase them.
You will learn:
- What are Stainless Steels Series 400 Grades 410 and 416 and 420?
- How Stainless Steels Series 400 Grades 410 and 416 and 420 are Made
- Uses for Stainless Steels Series 400 Grades 410 and 416 and 420
- Forms of Stainless Steel Series 400 Grades 410 and 416 and 420
- And much more …
Chapter 1: Understanding 400 Series Stainless Steel
The 400 series of stainless steels are distinguished by their significant carbon content, endowing them with remarkable strength and resistance to wear. In contrast to austenitic stainless steels, the 400 series offers less corrosion resistance but can undergo hardening via heat treatment, making it well-suited for a range of tough applications.
- Grade 410 is a versatile martensitic stainless steel, offering a blend of strength along with moderate corrosion resistance.
- Grade 416, a derivative of 410, is uniquely recognized as the sole free-machining stainless steel, providing excellent machinability alongside strong mechanical properties.
- Grade 420 excels due to its exceptional hardness, making it ideal for applications demanding high durability and wear resistance.
| Products in the Stainless Steel 400 Series | |
|---|---|
| Stainless Steel Plate | Mill Plates and Coil Plates |
| Stainless Steel Sheet | 2B/2D Finish, Polished Sheet, and Perforated Sheet |
| Stainless Steel Structural | Includes Structural beams, tubes, and channels |
| Stainless Steel Tubular | Available forms: rectangular, square, and circular tubing |
Choosing 400 series stainless steels hinges on various criteria. These steels, often with a martensitic structure, can be hardened through heat treatment and aging. Unlike other stainless steel series, the 400 series is known for its significant hardness, strength, and wear resistance, with Grade 410 as a general-use stainless steel, Grade 416 as the premier free machining option, and Grade 420 noted for its high hardness.
Grade 410 stainless steel includes 11.5% chromium, offering some corrosion resistance—a quality that can be further improved by polishing, tempering, and hardening. Recognized for its versatility, Grade 410 is commonly used in the manufacture of knife blades, scissors, culinary tools, and firearm parts.
The enhanced machinability of Grade 416 is partly attributed to its sulfur and phosphorus content. Its widespread use is also due to its lower cost and ease of availability. Grade 416’s tensile strength ranges from 510 MPa to 800 MPa, with a hardness rating between 230 HB and 320 HB.
Grade 420 stainless steel is lauded for its exceptional hardness and wear resistance compared to Grade 410, making it perfect for applications necessitating toughness. Its elevated carbon content enables its hardness to be increased to 55+ HRC through heat treatment. Grade 420 is widely used in the production of knife blades, scissors, surgical tools, firearm clips, hip implants, and industrial cutting implements. While its corrosion resistance is moderate, it can be enhanced through polishing and tempering to suit environments where strength and resistance to wear are crucial.
Chapter 2: How Series 400 Grades 410, 416, & 420 Stainless Steel are Made
Each type of stainless steel is engineered to have properties that make it ideal for specific applications. Series 400 has a higher carbon content to increase its strength and make it more resistant to wear, it is less resistant to corrosion and rust. As with all types of steel, series 400 is made from iron with a chromium content of 11% up to 27%, 1% of carbon, and 2.5% of nickel. Since the martensitic crystalline structure of series 400 varies, the strength and hardness of its different grades varies.
The Manufacturing of Stainless Steel Series 400
The first step in the manufacture of stainless steel series 400 is accumulating the appropriate materials. Each of the elements for series 400 are chosen in the proper ratios to create properties for specific types of series 400 stainless steels. In many cases, ratios are on a range because of the potentiality of possible variances in the purity of the elements placed in the mix.
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Melting – Once the proper combination of materials is collected, they are placed in a melting furnace that can take several different forms, which is determined by the type of energy used to power the furnace. Although gas and propane are available, many melting furnaces use electric power. To properly mix the various alloys, the furnace is heated to the melting point for each alloy, a process that can take between 8 and 12 hours. The melting process creates a molten mixture for the next step in the stainless steel manufacturing process.
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Excess Carbon Removal – The carbon removal process is carefully monitored since the amount of carbon removed determines the type of series 400 stainless steel. The process for the removal of carbon is completed by vacuum oxygen decarburization (VOD) or an argon oxygen decarburization (AOD) system. The careful regulation of this process is necessary since the amount of carbon influences the tensile strength and hardness of the stainless steel. Since series 400 stainless steel has a high carbon content, the regulation of carbon is a critical aspect of the manufacturing process.
- Turning and Stirring – An important factor regarding the quality of series 400 stainless steels is the even distribution of the different alloys to create a homogeneous mixture. To ensure the proper consistency, the mixture is put through a stirring and turning process, which has the additional effect of removing certain components from the mixture. The resulting outcome is a uniform molten combination of alloys that ensures the quality of the stainless steel.
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Forming Stainless Steel Series 400 – The forming of the molten stainless steel involves putting the molten material through a casting process, which can be continuous or ingot casting. With continuous casting, the molten stainless steel is fed into a mold with the desired shape. It enters the mold through holes in the appropriate portions to fit the mold. Heat is removed by water that surrounds the mold, a process that solidifies the molten metal. The final forms can be bars, tubes, sheets, or specialized forms.
- Annealing – Annealing helps the metal regain its grain structure before it is shaped any further. The stainless steel is heated and held at a critical temperature to reset the microstructure. During the process, the grains recrystallize and grow. Immediately after the grains recrystallize, they are cooled to avoid excess grain growth. The process of annealing may be repeated several times to achieve the necessary thickness. Prior to annealing, stainless steel series 400 has an austenitic grain structure. When it cools to room temperature, it transforms for a martensitic structure.
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Cutting and Shaping – To prepare stainless steel for the final product for which it has been manufactured, it is cut and shaped such that it has the proper dimensions for the requirements of an application. The shaping and cutting processes take several forms and vary in accordance with the size and shape of the stainless steel billet. Metal shears, CNC machining, and laser cutting are some of the methods used to create the proper shape.
Surface Finishes – There are many types of finishes for stainless steel series 400, which is a process that is applied to stainless steel to increase its durability, corrosion resistance, smoothness, and grain pattern. Although finishes can enhance the appearance of stainless steel series 400, they can also help improve the metal’s performance, strength, reliability, and properties. Rolling, polishing, and blasting are finishing methods that affect how the stainless steel is produced, its thickness, surface, cleanliness, mechanical abrading.
The choice of surface finish is critical to how stainless steel series 400 meets the requirements of the application for which it is manufactured. Since series 400 stainless steels are mainly used for applications that require strength, they do not necessarily need an aesthetically appealing appearance. Due to its low resistance to corrosion, finishes are added to enhance the stainless steel series 400’s ability to resist rust and corrosion, which includes certain types of coatings.
Stainless Steel Grade 410
The process for the manufacture of stainless steel grade 410 follows the same steps as those for stainless steel in general. In most cases, the molten form of grade 410 is formed into ingots that are heated and hot worked by forging, rolling, and extrusion. The shaped forms are annealed to improve their ductility and workability. The finishing processes used on grade 410 include hot rolling, cold rolling, and more annealing or heat treatments.
Additional finishing methods are used to improve the properties of stainless steel grade 410 and include various types of surface treatments. Grade 410 is heat treated at 750°C up to 820°C (1382°F up to 1508°F) and quenched using oil, water, or air. Since the metal is brittle after quenching, it is tempered to relieve its internal stress and improve its toughness and ductility.
Mechanical Testing
Mechanical tests include testing the metal’s tensile strength, using the Brinell Hardness Test, and tests of the toughness of the metal using the Charpy V-notch test. The purpose of the tests is to determine stainless steel series 400’s ability to withstand loads, stress, and impacts.
Chemical Testing
Chemical testing is used to verify the grade of the stainless steel using nondestructive spectrochemical testing. Of the different types of tests, chemical testing is the most important since it determines the metal’s ability to resist corrosion using salt spray. As the salt spray is applied, the metal is examined to determine if the exposure to the salt spray is damaging or marring the metal. The longer stainless steel is unaffected by the salt spray, the higher is its corrosion resistance.
Chapter 3: Stainless Steel Grade 410
Stainless steel grade 410 is one of the most popular forms for stainless steel and is referred to as a general use stainless steel due to its ability to be used in a wide range of applications. Aside from its easy availability and low cost, grade 410 is marginally machinable and formable. Its lower cost is due to the limited use of expensive alloys in its composition and manufacturing.
The process for the manufacture of stainless steel grade 410 follows the same steps as those for stainless steel in general. In most cases, the molten form of grade 410 is formed into ingots that are heated and hot worked by forging, rolling, and extrusion. The shaped forms are annealed to improve their ductility and workability. The finishing processes used on grade 410 include hot rolling, cold rolling, and more annealing or heat treatments.
Like other grades of series 400 stainless steel, grade 410 has good resistance to corrosion, which can be enhanced through hardening, tempering, and polishing. The application of various treatments changes the properties of grade 410 especially its corrosion resistance. When properly treated, stainless steel grade 410 can be corrosion resistant in moist and wet environments and environments with mild chemicals. Regardless of the various treatments, grade 410 cannot be used in conditions where there is salt water or acidic chemicals.
The higher carbon content of stainless steel 410, at 0.1%, gives it its strength and reduces its ductility. Its 12% chromium content results in the formation of chromium carbide compounds that gives stainless steel 410 wear resistance and edge retention and is one of the reasons for its machinability. The blend of elements that combine to form stainless steel 410 gives it resistance to high temperature oxidation and scaling.
| Composition of Stainless Steel Grade 410 | ||||
|---|---|---|---|---|
| Alloy | Alloy | |||
| Iron | 85% or Higher | Manganese | 1.0% or Less | |
| Carbon | 0.08-0.15% | Silicon | 1.0% or Less | |
| Chromium | 11.5 to 13.5% | Sulfur | 0.03% or Less | |
| Nickel | 0.75% or Less | Phosphorus | 0.04% or Less | |
Stainless steel 410 can be cut, shaped, and formed due to being worked and quench hardened and tempered. Compared to stainless steels grades 304 and 316, stainless steel 410 is harder to machine, which is the reason 304 and 316 replace grade 410 for some applications.
Stainless steel grade 410 is an air hardening stainless steel that has to be preheated before welding and annealed before the weld cools, or the metal will harden and crack. It can be cold formed when annealed and hot formed at 750°C – 1150°C (1382°F – 2102°F). For less stressful forming processes such as bending, the preheating temperature can be substantially lower in the hundred-degree range. Although stainless steel grade 410 is machinable, it is normally annealed prior to the process and has to be put through decontamination and passivation after being machined.
The melting point of stainless steel 410 is 1495°C (2729°F) with a density of 7.65 g per cm³ (0.276 lb. per in³), specific gravity of 7.65, and modulus of elasticity in tension of 29x10⁶ psi or 200 GPa. Its tensile strength is 65,000 psi with a yield strength of 30,000 psi. On the Rockwell hardness scale, stainless steel 410 measures at HRB80, which is used to measure low carbon steels.
The martensite microstructure of grade 410 is a type of crystalline structure that has ferromagnetism. During heat treatment, the austenitic microstructure of grade 410 undergoes a transformation into a martensite microstructure, which gives the metal improved strength and hardness and its magnetic nature. This aspect of grade 410 makes it ideal for magnetic assemblies, magnetic sensors, and magnetic separators.
Chapter 4: Stainless Steel Grade 416
Stainless steel grade 416 has the highest machinability of all of the different stainless steels with a rating of 85%. The rating scale for machinability was established by the American Iron and Steel Institute (AISI) and is expressed as a percentage with carbon steel having a 100% rating, which means it is easy to machine. As the percentage for a metal moves below 100%, it is determined to be difficult to machine. Most stainless steels are in the 40% to 80% range.
The manufacture of stainless steel grade 416 follows the same process as that which is used for grade 410 and is a variation of grade 410 with a higher sulfur content to increase its machinability. Once grade 416 is formed into sheets, bars, rods, and pipes, it is hardened and polished to increase its resistance to corrosion. To increase its resistance to oxidation, it is heat treated at 760°C (1400°F).
Grade 416 is resistant to acids, alkalis, fresh water, and dry air but is less corrosion resistant than non-machinable stainless steels. In order to enhance the corrosion resistance of grade 416, it is hardened, which gives it a smooth surface. The hardening process for grade 416 involves heating the metal to 925°C up to 1010°C (1742°F up to 1850°F) followed by oil quenching and tempering.
In order to weld grade 416, the metal has to be preheated to 200°C up to 300°C (392°F up to 572°F), which is followed by annealing or stress relief. Grade 410 electrodes are ideal for the grade 416 welding process, and grade 309 filler rods can be used, as well.
Stainless steel grade 416 is the grade of stainless steel that is most often used for machining. The reason for the high machinability of grade 416 is its high sulfur content. In addition, grade 416 can be heat treated to further enhance its machinability, which gives it an improved machinability performance over austenitic 300 series stainless steels.
The machinability of all stainless steels is dependent on the elements and materials that are added to it. Many of the elements that are added increase stainless steel’s strength but make it difficult to machine, such as chromium, nickel, and molybdenum. The addition of sulfur increases the metal's machinability since it lowers the shear strength of inclusions that act as stress risers and weaken the steel. The lowered shear strength makes it possible for machined chips to break away from the work area more efficiently and helps avoid the build up of waste on the cutting tool, known as bird nesting. In addition to sulfur, other additives used to enhance machinability include selenium and calcium.
| Composition of Stainless Steel Grade 416 | ||||
|---|---|---|---|---|
| Alloy | Alloy | |||
| Iron | 85% | Manganese | 1.25% | |
| Carbon | 0.15% | Silicon | 1.0% | |
| Chromium | 12 to 14% | Sulfur | 0.15% | |
| Phosphorus | 0.06% | |||
Chapter 5: Stainless Steel Grade 420
Stainless steel grade 420 is a modified version of grade 410 with a higher carbon content, which increases its hardness and improves the metal’s strength and wear resistance. In annealed condition, it has good ductility and can be hardened up to 50 RHC. The corrosion resistance for grade 420 improves after the metal has been hardened and surface ground or polished.
In a hardened condition, stainless steel grade 420 has corrosion resistance against the atmosphere, foods, fresh water, alkalies, acids, steam, and crude oil. The strength and durability of grade 420 is due to its high carbon content, which also gives it higher hardness than grades 410 and 416. Stainless steel grade 420 has the highest hardness level of all of the low chromium stainless steels.
The ability to machine stainless steel grade 420 varies and depends on its level of hardness. When it is hardened to under 30 RHC, it is relatively easy to machine. If the hardness is over 30 RHC, the ability to machine it becomes difficult and challenging. If grade 420 is used above 427°C (800.6°F), it softens and loses its corrosion resistance.
The physical properties of stainless steel grade 420 depend on how it is tempered. In many cases, customers discuss with manufacturers how the metal is to be used, which allows manufacturers to temper it appropriately.
The introduction of stainless steel 420 was due to the demand for a stainless steel with superior hardness and exceptional wear resistance for the manufacture of tools, medical instruments, and cutlery. A unique feature of stainless steel grade 420 is its edge retention, which was the main reason for its development, as well as its toughness.
Stainless steel grade 420 can be welded using welding rods made of stainless steel grade 309. For purposes of welding, grade 420 is heated to 150°C up to 320°C (302°F up to 608°F). After which, welded parts are post heated.
As with grades 410 and 416, stainless steel grade 420 is used for a variety of applications. It is designed for applications that require a stainless steel with high hardness. The edge retention of stainless steel 420 makes it ideal for the manufacture of cutlery, surgical tools, scissors, shear blades, and knives.
| Composition of Stainless Steel Grade 420 | ||||
|---|---|---|---|---|
| Alloy | Alloy | |||
| Carbon | 0.41% | Vanadium | 0.046% | |
| Chromium | 12.69% | Copper | 0.05% | |
| Manganese | 0.74% | Phosphorus | 0.025% | |
| Silicone | 0.33% | Sulfur | 0.001% | |
| Nickel | 0.16% | Aluminum | 0.017% | |
| Molybdenum | 0.05% | |||
Chapter 6: Uses for Stainless Steel Grade 410
The applications for which stainless steel grade 410 is used require mild corrosion resistance, heat resistance, and strength. It is supplied to fabricators and manufacturers in sheets, bars, plates, rolled, coils, and drawn. The forms used by product producers are dependent on the dimensions and specifications of their product. As with all series and grades of stainless steel, there are specialized types of stainless steel grade 410 that are engineered for certain types of applications.
AWS E410-16 Stainless Steel
AWS E410-16 are coated electrodes with a titania flux coating, which are used for welding and repairing stainless steel grades 410, 416, 420, and 431. It is a coated electrode with hardenability with exceptional strength and moderate resistance to corrosion with a tensile range of 700 Mpa up to 850 Mpa. AWS E410-16 has excellent rust resistance and can be hardened to a Rockwell hardness of 40 depending on the amount of carbon it contains. There is a wide assortment of applications for which AWS E410-16 is used including bolts, bushings, and various types of fasteners.
Stainless Steel Grade 410 Bars
Stainless steel grade 410 round bars are used for aerospace, automotive, medical, natural gas, and petroleum applications. It is ideal for use in the manufacture of high stress parts due to its good corrosion resistance and exceptional strength, a characteristic of most series 400 stainless steels. Stainless steel grade 410 round bars are available in several configurations with diameters that range from less than an inch up to close to a foot.
ER410 Stainless Steel
ER410, like AWSE410-16, is used to weld stainless steels and to weld overlays on carbon steels. For it to be used for welding, ER410 has to match the chemical composition of the material to be welded. As an overlay for carbon steels, ER410 gives carbon steel resistance against corrosion and abrasion. It is a hardening filler metal that requires joints to be preheated to 176.7°C (350°F) prior to welding the joint.
Knife Blades
The various types of kitchen cutlery require a knife blade with strength, durability, and some resistance to corrosion. These factors are the reason that stainless steel grade 410 is used for the manufacturing of knives and flatware and for use in industrial food processing. The chromium content of grade 410 protects knife blades from the effects of the acidity of food and the corrosiveness of water. The heating process in the manufacture of grade 410 gives the knife blades their hardness and edge retention, which helps in their durability and longevity.
Stainless Steel 410S
Stainless steel 410S is a low carbon modification of stainless steel 410. The low carbon content and some alloy additions reduces austenite formations at high temperatures, which restricts the ability of stainless steel 410S from hardening. It remains soft and ductile after being rapidly cooled. The non-hardening characteristic prevents the steel from cracking when exposed to excessively high temperatures or welding. The ductility of stainless steel 410S makes it easy to form and shape and increases its viability for a wide range of applications from ore processing to plates and valves.
Gate Valves
Gate valves are used for fluids that flow in a straight line and require minimal restrictions. The composition and properties of the gate valve material is very important, since the range of liquids or gases widely vary and can affect the performance of the valve. High volume liquid and gas flow requires a gate valve with exceptional strength and corrosion resistance, which is the reason that stainless steel 410 is used in gate valve construction and the manufacture of different types of gate valves. The mechanical and physical properties of stainless steel 410 make it an ideal material for gate valves for the oil and gas, pharmaceutical, and waste water treatment industries.
Leading Manufacturers and Suppliers
Chapter 7: Uses for Stainless Steel Grade 416
Stainless steel grade 416 is a free machining stainless steel, which is a metal that allows small chips to break evenly during machining. The machining process can be completed continuously since the machined chips do not need to be removed, a factor that allows for longer run times and machining cycle times. Stainless steel 416 is normally used for parts and components that require extensive machining and corrosion resistance, such as electric motors, pumps, valves, screw machines, studs, and gears.
Many of the uses for stainless steel grade 416 are the same as those for grade 410 with the difference between the two being 416’s strength and toughness. A common use for stainless steel 416 is as fasteners due to its strength. In addition, it is used for the manufacture of cutlery and kitchenware, like grade 410. A unique use of grade 416 is as components for firearms.
Firearms
The use of grade 416 in the manufacture of firearms is due to its strength, resistance to rust, and resistance to heat. The main part of a firearm that is made of stainless steel is the barrel through which the fired projectile travels. It is included in the barrels of rifles, pistols, competitive rifles, and military weapons. In order to be approved for use in firearms, grade 416 is tested ultrasonically under the American Society of Testing and Materials (ASTM) stipulation 2375, which outlines the parameters for the ultrasonic test.
In addition to the barrels of firearms, grade 416 has been found to have the strength, endurance, and stability to perform as other aspects of firearms, such as triggers and firing pins. Any aspect of a weapon that requires constant and repetitive use is made of grade 416 stainless steel to ensure the safety of a weapon and its performance. The barrels of firearms made with grade 416 stainless steel have greater accuracy and are the reason competitive and target shooters prefer grade 416 barrels.
Springs
Springs are various sizes of wires that are wound in a helical fashion with each type of spring having a different and unique form to fit the requirements of an application. They have to be exceptionally durable and able to easily recover after being stressed or deformed. Stainless steel grade 416 is an ideal material that is used to form springs due to its strength, durability, machinability, and rust and corrosion resistance. The types of springs manufactured using stainless steel 416 include the full spectrum of springs with larger springs being the most common.
Stainless Steel Grade 416 Bars
Stainless steel grade 416 bars are available in round bars, flat bars, and square bars. The unique machining characteristics of stainless steel grade 416 makes it ideal for use in agriculture, gas turbines, and motor shafts. The popularity of stainless steel 416 bars is due to the steel's free machining properties even though it has low corrosion resistance. Bars of stainless steel 416 are available annealed and T conditioned.
Chapter 8: Uses for Stainless Steel Grade 420
Stainless steel grade 420 was developed for use in the manufacture of knives. The quality of knives produced using grade 420 varies in accordance with the amount of carbon it contains, which can range from 0.15% up to 0.38%. Grade 420 with high end carbon can have a hardness rating of 57 RHC up to 58 RHC. Its toughness is due to its low carbide content.
Surgical Tools
Stainless steel grade 420 is referred to as a surgical grade stainless steel and capable of being used for biomedical applications. Although the term medical grade stainless steel is used to describe grade 420, there isn’t a formal definition for what surgical stainless steel is. In most cases, any stainless steel with sufficient corrosion resistance is referred to as surgical stainless steel. In the case of grade 420, its edge retention, strength, hardness, and toughness makes it ideal for the manufacture of surgical tools.
Hand Tools
Stainless steel grade 420 has many of the mechanical properties of carbon steel, which makes it ideal for the shaping and forming of tools with the mechanical characteristics of industrial tools. In some cases, grade 420 is used in place of grades 304 and 316 due to its exceptional tensile strength and hardness. Tools made using grade 420 have a longer useful life due to the metal's high wear resistance.
Needle Valves
Needle valves are used for accurate control of the flow of clean gases and liquids. They are designed for even and smooth control of flow for fluids or gases with a low flow rate and significant pressure drop between their inlet and outlet. The strength and durability of stainless steel grade 420 as well as its corrosion resistance and hardness make grade 420 an ideal material for needle valve applications.
Stainless Steel Grade 420 HC
Stainless steel grade 420 HC has a high carbon content of 0.44% up to 0.60%, which is unlike grade 420 with a carbon content of 0.12% up to 0.14%. In addition, stainless steel grade 420 HC has an increased chromium content of 14%, a factor that gives the metal increased corrosion resistance. Grade 420 HC sharpens easily and can endure constant use as well as being rust resistant. It is commonly used to manufacture knives and is popular in the manufacture of machetes.
Stainless Steel Grades 420J1 and 420J2
Stainless steel grades 420J1 and 420J2 are a low cost stainless steel that is used for the manufacture of knives. They are differentiated by their carbon content with grade 420J1 having a low carbon content while grade 420J2 has a medium carbon content.
- Stainless Steel Grade 420J1 - Grade 420J1 is a high hardness and high strength stainless steel with carbon content of 0.16% up to 0.25%, 1% chromium, and a very small amount of molybdenum. As with all forms of stainless steel, grade 420J1 has good corrosion resistance with some wear resistance. The distinguishing feature of grade 420J1 is its low carbon content, which is unlike most grade 420 stainless steel.
- Stainless Steel Grade 420J2 - Grade 420J2, as with grade 420J1, has high hardness and wear resistance with a carbon content of 0.26% up to 0.35% with a chromium content of 1%. The higher carbon content of 420J2 gives it its higher hardness when compared to grade 420J1 but is used to manufacture many of the same products.
Chapter 9: Common Forms of Stainless Steel Grades 410, 416, & 420
The various forms of stainless steel grades 410, 416, and 420 are produced to meet the requirements of manufacturers and take several different shapes. During the manufacturing process, the molten stainless steel is formed into different shapes for shipment. Common forms used in the production of grades 410, 416, and 420 are sheets, bars, plates, billets and ingots, coils, or being cold drawn through a die to form a specialized shape.
Plates
Stainless steel plates have a similar structure to that of sheets with a greater thickness. Although both forms of stainless steel are in the form of thick flat pieces of metal, the differentiating factor between the two forms is their thickness with flat forms that have a thickness of 2 to 3 mm (0.079 in up to 0.12 in) being defined as plates. Plates are produced in the same way as sheets by having the material rolled through a mill.
Rods
Rods have a cylindrical shape and are used in their manufactured form as supports. They come in different diameters in accordance with the purpose for which they are manufactured. Rods also come in different lengths, a factor that makes them flexible enough to be used for the CNC process for producing screws and fasteners.
Coils
Of the various forms of stainless steel series 400, coils are one of the most common due to their versatility. They are thin sheets of stainless steel that are rolled into a coil shape and cut to the desired size and configuration required by an application. Coils are available as flat strips and have thicknesses that vary from 0.02 mm up to 6 mm (0.0008 in up to 0.24 in).
Coils are typically used in applications requiring high strength and durability, especially where the material needs to be processed further, such as cutting, slitting, or rolling into more specialized shapes. The wide use of stainless steel series 400 coils includes kitchen appliances, automotive parts, and materials for construction. Series 400 coils are due rust resistant, which gives them an advantage over other types of metal coils.
Characteristics of Series 400 Coils
- Dimensions - Series 400 coils are available in different widths, thicknesses, and finishes, allowing for customization based on their end use requirements.
- Heat Treatment - Just like plates, sheets, and other forms, coils can be heat treated to increase hardness and strength, making them suitable for the demanding applications of the automotive, aerospace, and manufacturing industries.
Applications
- Automotive and Aerospace - Coils of stainless steels series 410, 416, and 420 are often used for manufacturing components that require precision and strength, including exhaust systems, structural parts, and engine components.
- Manufacturing - Coils are processed further into more specialized products, such as precision strips, tubes, or sheets, which are then used in everything from appliances to industrial machinery.
- Construction - Stainless steel coils are sometimes used in construction applications, especially where strength and resistance to wear are essential.
Coils, like other forms of stainless steel 400, can be heat treated and finished in a variety of ways to meet specific requirements. Grade 420 coils, in particular, are used in applications where high hardness and wear resistance are critical, such as cutlery and heavy duty industrial components.
Bars
Bars are a unique form of stainless steel and take a wide assortment of shapes that include round, hexagonal, strips, and specialized ones for specific applications. They are hot or cold rolled to achieve the necessary hardness for an application. Bars can have complex profiles that have different cross-sectional shapes. This aspect of bars is one of the reasons for their wide use.
Sheets
Sheets are one of the more common forms of stainless steel that are used for shipping since they fit easily on pallets and can be loaded in stacks. Like the other forms of stainless steel, sheets come in a wide variety of sizes. They can be rectangular or square depending on the preference of the manufacturer. In the manufacturing process, sheets can be laser cut, stamped, bent, and deformed to fit the requirements of a product or application. They are seldom used in their original form and are normally reengineered by a mechanical process.
Billets and Ingots
Billets and ingots are another common form of stainless steel that are used for shipping and manufacturing. They are used in a wide array of manufacturing processes from casting to extrusion. The shapes of stainless steel billets are easy to manipulate and handle. They can be easily placed in furnaces to melt the metal for being injected into a casting mold.
Strips
The factor that differentiates stainless steel 420 strips from coils is their width that range from 1.5 mm up to 600 mm (0.059 in up to 23 in). Although stainless steel 420 strips fall into the category of coils, their small widths distinguish them. Regardless of their widths, the thickness of 420 strips is the same as that of coils. The wide use of stainless steel 420 strips is due to their exceptional strength, corrosion resistance, and durability. They are used to manufacture cutlery, medical instrumentation, scissors, springs, and blades. As with other forms of stainless steel 420, the shape and appearance of strips are changed and altered by grinding and polishing.
Chapter 10: The Benefits of Stainless Steel Series 400
Stainless steel series 400 is known for its strength, hardness, and wear resistance and is used in applications by several industries. The list of uses for series 400 stainless steels includes simple cutlery and kitchen tools, industrial machinery, medical instruments, and petrochemical equipment. It has the necessary quality and performance that is demanded by manufacturers.
Alloys in the 400 series, such as grades 410, 416, and 420, are versatile, dependable, and resilient and provide a cost effective and reliable metal to meet the needs of high stress applications. The wear and tear resistance of stainless steels series 400 makes it applicable for specialized and unique applications.
Cost Effective
The lower nickel content of series 400 stainless steels significantly affects its cost compared to other types of stainless steel. It is one of the reasons that series 400 is selected for so many applications.
Manufacturing
The ease of forming and shaping of series 400 makes it possible to quickly produce the metal products and components. It is one of the easiest steels to produce compared to other forms of steel. The ability to form and shape series 400 is part of the reason for its wide usage.
Maintenance
Series 400 has similar strength compared to carbon steel but with rust and corrosion resistance, which makes it easier to maintain compared to carbon steels. While carbon steel requires the applications of coatings for protection from rust and corrosion, series 400 is naturally resistant.
Wear
One of the outstanding characteristics of series 400 stainless steels is their ability to endure wear and tear, which is unlike other forms of stainless steel. This aspect makes series 400 stainless steels long lasting and highly durable and makes it an option for applications that require strength and endurance.
Conclusion
- One of the distinguishing features of stainless steel series 400 is its manganese content, which is 1% higher than that of series 300 stainless steels.
- The strength and durability of stainless steel series 400 is due to its higher carbon content, which gives it a martensitic crystalline structure.
- The different forms of stainless steel series 400 includes plates, sheets, bars, and tubes that are formed and shaped to meet the requirements of manufacturers.
- The extra strength and durability of stainless steel 400 series increases its usefulness for stressful and demanding applications but lowers its resistance to corrosion and rusting compared to other forms of stainless steel.
- Stainless steel 410 is referred to as a general-purpose stainless steel that is used to produce components and parts that have to endure high stress.
- Stainless steel 416 is the first free machining stainless steel and has the highest machinability of all stainless steels. It has exceptional strength and resilience when hardened and tempered.
