Stainless Steel 440C
Stainless Steel 440C is a high carbon steel that is hardened into martensite characterized with very good hardness, wear resistance and most importantly edge retention. It is also common in areas where high corrosive resistance and high strength are required such as knife blades, bearings, and surgical tools.
Stainless Steel 440C belongs to one of the high carbon steel that has been categorized as a martensitic stainless steel. This composition of stainless steel is categorized in the AISI (American Iron and Steel Institute) system where the “440” subgroup corresponds to a particular composition and properties, while the “C” character indicates that the carbon content is higher than that of grades 440A and 440B.
According to the full designation, this material is an AISI 440C Stainless Steel alloy. This for example contains about 16-18% Cr, 1.0-1.2% C and other minor elements like Mn, P, S, Si. The increased carbon content is responsible for additional hardness and abrasion resistance in the alloy, and hence it is useful in such instances where these properties are important.
Appropriate for cutting in the annealed condition, capable of hardening and tempering, usually not welded because of air-hardening features, and hot or cold worked with some preheating and cooling arrangements.
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Stainless Steel 440C Properties
Mechanical Properties
- Tensile Strength: 760-1970 MPa
- Yield Strength: 450-1900 MPa
- Bulk Modulus: 166 GPa
- Shear Modulus: 83.9 GPa
- Elastic Modulus: 200 GPa
- Poisson's Ratio: 0.27-0.30
- Elongation at Break: 2-14%
- Hardness (Rockwell B): 97
Physical Properties
- Density: 7.80 g/cm³
- Melting Point: 1483°C
Thermal Properties
- Thermal Expansion Coefficient: 10.2 µm/m°C
- Thermal Conductivity: 24.2 W/mK
Electrical Properties
Generally, stainless steels have moderate electrical conductivity.
Post Treatments
- Annealing: Heat and maintain at 843-871°C, cooling the sample to the ambient temperature simply afterwards.
- Tempering: Heat to, but not exceeding 148°C and hold for a reasonable period of time.
- Hardening: Heat treat to 760°C, followed by a ramp to 1010°C and cooling in air or oil.
Common Applications
- Gage blocks
- Cutlery
- Ball bearings and races
- Molds and dies
- Knives
- Valve components
- Measuring instruments
Recommended Reading
Frequently Asked Questions (FAQs)
Q: What are the main properties of 440c stainless steel?
A: Identifying the properties of 440c stainless steel high hardness and wear resistance can be accounted it its high carbon content. It is a martensitic stainless steel with a fair degree of corrosion resistance. This makes it suitable for use in knife blades and ball bearings.
Q: What is the heat treating process of 440c stainless steel?
A: The mechanical properties of 440c stainless steel are improved with heat treatment. Heat treatment like quenching and tempering helps the steel to be used in cutlery and other applications which have a degree of possible high wear.
Q: How does 440c Stainless Steel stand to Corrosion?
A: 440c stainless steel is relatively reasonable in terms of corrosion prevention properties because of the alloying with chromium and iron-carbon ingredients. It can be used in places with low moisture levels and can always be coated with some type of rust preventive, but it should be exercised in exceptionally harsh environments.
Q: Is welding possible on 440c stainless steel?
A: Welding is feasible on 440c stainless steel, but it is important to post machine the welded joint to standard so as not to distort the mechanical properties of the joint. Pre-heating and post weld heat treatment can be employed in order to reduce the possibility of cracking in the welded bond.
Q: What specifications are used for 440c stainless steel?
A:Though various other standards may apply, the properties of 440c stainless steel are largely determined by the ASTM specifications, which prescribe the chemical composition, mechanical properties, and heat treatment practices of the steel. This enhances the performance of the steel in its intended use.
Q: What are the mechanical properties of 440c stainless steel?
A: Among the mechanical properties of 440c stainless steel is the undefined yield strength of 850 MPa, the tensile strength, and the undefined Brinell hardness of about 56-58 HRC. Its properties support high-strength applications such as valves and performance knife blades.
Q: How does the carbon content of 440c influence its properties?
A:Another contributor to the hardness and wear-resistant properties of 440c stainless steel is the high carbon content, which is in the range of 1.2- 1.5%. This carbon level allows it to attain higher hardness levels when heat treated, hence ideal for cutting tools and other productive uses.
Q: What applications commonly use 440c stainless steel?
A:440c steel is practically used for a knife’s cutting blades, ball bearings, utensils, and even medical instruments because of its great hardness, wear-resistant and decent corrosion resistance.
Q: In what ways does the heat treatment process increase the wear resistance of 440c?
A: Heat treatment process such as hardening and tempering has been proven to enhance the wear resistance of 440c stainless steel. The heating and cooling sequence changes its microstructure and makes it harder and more robust to withstand a harsher environment.