Each type of stainless steel has unique features, making it suitable for specific applications. For the 400 series stainless steel, its higher carbon content and martensitic crystal structure give the final product higher strength and wear resistance. However, under certain conditions, it can show signs of corrosion and rust.
For people who need to use or work with this alloy, understanding the features and functions of the 400 series stainless steel can help them choose the most suitable type for their needs.
In this article, we will introduce the common types of 400 series stainless steel and their applications.
What is 400 Series Stainless Steel?
The 400 series stainless steel includes two grades: ferritic and martensitic. Most of these are martensitic, which means they have a higher hardness and strength, but the corrosion resistance is not as good as that of the 300 series. However, they are stronger and provide better solutions for specific conditions.
Ferritic stainless steel can be used as a cheaper alternative for decoration or specific heat- and acid-resistant applications. Martensitic stainless steel has a higher carbon content and hardness, making it suitable for making tools like knives and razors. Its carbon content forms a martensitic crystal structure, which gives it high strength and wear resistance. However, it is not as resistant to corrosion as austenitic stainless steel, and in some cases, it can rust or corrode. But heat treatment can make it harder.
400 Series Stainless Steel Chemical Composition
400 series stainless steel is mainly made of iron, with other elements including 11% to 27% chromium, about 1% carbon, and up to 2.5% nickel.
The table below shows the chemical composition of common 400 series stainless steels.
Grade | (Cr) | (Ni) | (Ti) | (S) | (Mo) | (Fe) | (C) | Other Elements |
405 | 10.5% – 11.5% | – | – | – | – | Balance | Low | Ferritic Steel |
408 | 10.5% – 11.5% | 7% – 8% | – | – | – | Balance | – | Basic elements |
409 | 10.5% – 11.5% | – | Titanium as stabilizer | – | – | Balance | – | Basic elements |
410 | 11.5% – 13% | – | – | – | – | Balance | Relatively high | Martensitic Steel |
416 | 12.5% – 13.5% | – | – | Sulfur (0.15%-0.30%) | – | Balance | – | Easy-to-machine |
420 | 12% – 14% | – | – | – | – | Balance | High | Used for heat treatment |
430 | 16% – 18% | – | – | – | – | Balance | – | Basic elements |
440 | 16% – 18% | – | – | – | – | Balance | High | Higher-grade cutlery steel |
446 | 23% – 27% | – | – | – | Molybdenum (0.5%-1%) | Balance | – | Includes Molybdenum and Niobium |
410S | 11% – 13% | – | – | – | – | Balance | – | – |
410HT | 11% – 12% | – | – | – | – | Balance | – | – |
416HT | 12.5% – 13.5% | – | – | – | – | Balance | – | – |
430F | 17% – 18% | – | – | – | Molybdenum (0.5%-1%) | Balance | – | Improved corrosion resistance |
Advantages of 400 Series Stainless Steel
Strength and Wear Resistance
The 400 series stainless steel (especially martensitic stainless steel) has a relatively high carbon content, which forms a martensitic crystal structure. This gives it higher strength and excellent wear resistance.
440 stainless steel, often used for making high-end knives, has high carbon content. After proper heat treatment, it can greatly increase the hardness and sharpness of the knife and maintain a good edge during frequent use. In applications that require high strength, the 400 series is often better than the 300 series.
Cost Advantage
Ferritic stainless steel in the 400 series (like 409 stainless steel) is an affordable option. It is cheaper and is widely used in areas where corrosion resistance and strength are not the highest priority.
In the manufacturing of car exhaust pipes, 409 stainless steel’s cost advantage allows car manufacturers to reduce production costs while still meeting basic performance standards. In contrast, high-performance 300 series stainless steels are more expensive.
Hot Working Performance Advantage
Ferritic stainless steels in the 400 series have good hot working properties. They can be made into various shapes like thin sheets and pipes through processes like rolling and extrusion.
430 ferritic stainless steel can be hot worked into complex shapes like refrigerator cabinet panels, while other types of stainless steel, such as duplex stainless steels, may require more complex process control during hot working.
Magnetic Properties
The 400 series stainless steel (both ferritic and martensitic) usually has magnetic properties, which can be useful in applications that require magnetic attraction.
For example, 430 stainless steel used in some car interior parts can have magnetic properties that are useful for magnetic interior components. On the other hand, 300 series austenitic stainless steel generally does not have magnetic properties and cannot meet such needs.
Common Grade of 400 Series Stainless Steel
405 Stainless Steel
Ferritic steel, chromium content gives corrosion resistance, low carbon and nitrogen, good weldability, stable high-temperature strength, strong magnetic properties, fair machinability.
405 Stainless Steel Applications: Mainly used in chemical pipeline welding, simple metal structures, such as small chemical plant pipelines, equipment supports, etc.
408 Stainless Steel
Heat-resistant type, chromium and nickel provide some heat resistance, but lack stabilizing elements, resulting in poor corrosion resistance, can be damaged in corrosive environments.
408 Stainless Steel Applications: Mainly used in industrial furnace internal supports, high-temperature ventilation pipe supports, and other heat-resistant but not highly corrosion-resistant applications.
409 Stainless Steel
Economic ferritic steel, chromium provides basic corrosion resistance, ferritic structure makes it easy to process, low cost, commonly used in general environment parts.
409 Stainless Steel Applications: Widely used in car exhaust pipes, agricultural equipment frames, industrial furnace outer protection, etc., where cost is sensitive and performance requirements are not high.
410 Stainless Steel
Martensitic steel, chromium content provides some corrosion resistance, high strength and hardness after heat treatment, wear-resistant but poor weldability, magnetic.
410 Stainless Steel Applications: Commonly used for tools, pump parts, dental surgical instruments, hardware connectors, and other areas requiring strength and wear resistance.
416 Stainless Steel
Easy-to-machine martensitic steel, sulfur improves machinability, chromium content provides basic corrosion resistance, performance improves after heat treatment.
416 Stainless Steel Applications: Mainly used for automatic screw machine parts, motor components, gears, pump valve parts, etc., requiring high machinability.
420 Stainless Steel
Martensitic steel, high carbon content provides good hardness and strength after heat treatment, chromium ensures some corrosion resistance, good polishability, fair toughness.
420 Stainless Steel Applications: Widely used in high-end cutlery, decorative knives, and some precision instruments requiring hardness and appearance.
430 Stainless Steel
Ferritic steel, high chromium content, good corrosion resistance, excellent formability, good thermal conductivity, but low strength and hardness, poor high-temperature resistance.
430 Stainless Steel Applications: Commonly used in car interior parts, refrigerator panels, dishwasher liners, household appliance exteriors, etc., requiring formability and corrosion resistance.
440 Stainless Steel
High-carbon martensitic steel, high carbon provides excellent hardness, strength, and wear resistance, chromium provides corrosion resistance, but poor plasticity, toughness, and machinability.
440 Stainless Steel Applications: Mainly used in high-end cutlery, industrial knives, precision instruments, and high-wear parts requiring high hardness and wear resistance.
446 Stainless Steel
Ferritic steel, high chromium content and contains molybdenum and niobium, excellent high-temperature resistance and oxidation resistance, stable performance in high-temperature corrosive environments.
446 Stainless Steel Applications: Commonly used in high-temperature furnace linings, high-temperature pipeline supports, high-temperature heat exchanger parts, and other critical high-temperature applications.
410S Stainless Steel
Low-carbon version of 410, moderate chromium content, reduces austenite formation at high temperatures, prevents hardening and cracking, excellent corrosion and oxidation resistance after annealing.
410S Stainless Steel Applications: Used in annealing boxes, distillation tower trays, petroleum refining equipment, gate valves, and other industrial equipment requiring corrosion resistance and crack prevention.
410HT Stainless Steel
Heat-treated version of 410, chromium content ensures some corrosion resistance, high strength and hardness, suitable for environments with light corrosion and requiring strength.
410HT Stainless Steel Applications: Commonly used in gas and steam turbine blades, tools, hardened steel balls, kitchen utensils, and other products requiring strength.
416HT Stainless Steel
Heat-treated version of 416, increased strength and hardness, reduced corrosion resistance, excellent machinability, magnetic, and low friction properties.
416HT Stainless Steel Applications: Used for motors, gears, automatic screw machine parts, pump valve parts, washing machine parts, and other components requiring machinability and strength.
440 Stainless Steel
Improved version of 430 with added molybdenum to enhance corrosion resistance, excellent machinability, suitable for precision parts that require repeated machining.
430F Stainless Steel Applications: Mainly used for precision instrument components, fine-tuning parts, and other parts requiring machining accuracy and corrosion resistance.
If you would like to learn more about 400 stainless steel or investment casting materials, feel free to contact us.
Manek Casting specializes in providing high-quality investment cast parts made from metals with significant advantages. We adhere to top metal casting standards and strict testing and inspection processes, offering reliable, high-quality precision investment casting services to various industries. Manek Casting is your trusted partner!
Magnetism:
300 Series: Due to its austenitic structure, the electron spins are disordered, so it is usually non-magnetic or weakly magnetic. It is widely used in electronic devices and areas sensitive to magnetic fields, such as medical MRI equipment, to avoid interference with sensitive instruments and ensure smooth operation.
400 Series: Ferritic and martensitic stainless steels contain more unpaired electrons and are magnetic. They are commonly used in motors, generators, and magnetic clamps. The magnetic properties help improve electromagnetic conversion efficiency and meet the needs for adsorption and fixation.
If you would like to learn more about 400 stainless steel or investment casting materials, feel free to contact us.
Manek Casting specializes in providing high-quality investment cast parts made from metals with significant advantages. We adhere to top metal casting standards and strict testing and inspection processes, offering reliable, high-quality precision investment casting services to various industries. Manek Casting is your trusted partner!
