Stainless Steel 440C · temper · default condition
Stainless Steel 440C Annealed
Properties of the Annealed condition, compared with the other 440C tempers.
Stock condition for bar/plate that will be machined and then hardened by the customer.
What is 440C Annealed?
440C Annealed is 440C in the Annealed temper — stock condition for bar/plate that will be machined and then hardened by the customer. 440C Annealed has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 70% of stainless steel grades. Elongation at break is 14% and the elastic modulus is 200 GPa (29 Msi). 440C Annealed has a density of 7.68 g/cm³ (0.277 lb/in³), lighter than 94% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Advantages
- Polishes to a fine finish — 80/100, better than 89% of stainless steel grades
- High electrical conductivity — 2.9 % IACS, better than 87% of stainless steel grades
- Conducts heat well — 24.2 W/m·K (14 BTU/hr·ft·°F), better than 84% of stainless steel grades
- Easy to machine — 45/100, better than 84% of stainless steel grades
Limitations
- Difficult to weld — 12/100, worse than 99% of stainless steel grades
- Limited ductility — 14%, worse than 91% of stainless steel grades
- Needs corrosion protection — 42/100, worse than 90% of stainless steel grades
- Limited formability — 25/100, worse than 79% of stainless steel grades
440C Annealed properties
Typical room-temperature values for 440C Annealed — 15 properties are specific to this condition; the rest are grade-level values shared by every 440C temper. Each bar shows where the value sits among the stainless steel grades in FabDigit's library — further right is higher.
Physical3
440C Annealed has a density of 7.68 g/cm³ (0.277 lb/in³), lighter than 94% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Mechanical16
440C Annealed has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 70% of stainless steel grades. Elongation at break is 14% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
440C Annealed is rated for continuous service to 425°C (797 °F). It conducts heat at 24.2 W/m·K (14 BTU/hr·ft·°F), better than 84% of stainless steel grades. Thermal expansion is 10.2 µm/m·K (5.67 µin/in·°F).
Electrical3
440C Annealed conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (42/100), worse than 90% of stainless steel grades.
Sustainability4
Producing a kilogram of 440C Annealed takes about 53 MJ of energy and emits 4.3 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 60%.
Manufacturability6
440C Annealed's machinability is fair (45/100, better than 84% of stainless steel grades); weldability not recommended (12/100); formability poor (25/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 440C tempers and conditions
440C is also supplied in 6 other conditions. The full side-by-side table is on the 440C overview.
- AnnealedDefaultStock condition for bar/plate that will be machined and then hardened by the customer.450 MPa yield · 24 HRC
- H&T 58-60 HRCPick when maximum wear resistance and dimensional stability are required (bearing races, valve balls).1,950 MPa yield · 59 HRC
- Hardened & TemperedStandard service condition for bearings, knife blades and wear parts needing maximum hardness with usable corrosion resistance.1,900 MPa yield · 58 HRC
- H&T 54-56 HRCUse where slightly higher toughness / lower cracking risk is worth a few points of hardness (cutlery, shafts).1,720 MPa yield · 55 HRC
- H&T 48-52 HRCOnly for parts needing moderate hardness with elevated-temperature stability; corrosion resistance and toughness are reduced by carbide precipitation.1,500 MPa yield · 50 HRC
- Annealed + Cold DrawnChoose for small-diameter precision bar with better straightness/surface than hot-rolled annealed.620 MPa yield · 28 HRC
Working with 440C Annealed
Is 440C easy to machine?
Machine only in the annealed condition with rigid setups, sharp carbide tools, slow speeds and generous coolant; after hardening use grinding, EDM or CBN.
Can 440C be welded?
Welding is generally not recommended — preheat 200–300 °C, use 440C or austenitic filler, and follow with a full anneal to avoid cracking.
Can 440C be formed, bent or molded?
Cold forming is limited to gentle bending of annealed sheet; forge 1050–1150 °C and cool slowly with an immediate anneal to prevent quench cracks.
What surface finishes work on 440C?
Passivate in nitric or citric acid after grinding/polishing for best corrosion resistance; hard-chrome or PVD coatings and mirror polishing are common for knives and bearings.
440C chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Chigh carbon gives primary M23C6/M7C3 carbides for wear resistance | 0.95 – 1.2 | 1.05 |
| Cr | 16 – 18 | 17 |
| Mo | ≤ 0.75 | 0.5 |
| Mn | ≤ 1 | 0.4 |
| Si | ≤ 1 | 0.4 |
| P | ≤ 0.04 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
440C Annealed — frequently asked
What is 440C Annealed used for?
440C Annealed is typically used for ball and roller bearing races, surgical instruments, knife blades, valve components and seats, gauges and measuring tools and pump shafts. In short: highest hardness stainless tool.
What is the yield strength of 440C Annealed?
440C Annealed has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 70% of stainless steel grades. Strength varies by condition: see the 7 listed tempers.
Is 440C Annealed easy to machine?
Reasonably — machinability is rated fair (45/100, better than 84% of stainless steel grades). Machine only in the annealed condition with rigid setups, sharp carbide tools, slow speeds and generous coolant; after hardening use grinding, EDM or CBN.
Can 440C Annealed be welded?
Not readily — weldability is rated not recommended (12/100). Welding is generally not recommended — preheat 200–300 °C, use 440C or austenitic filler, and follow with a full anneal to avoid cracking.
What surface finishes work on 440C Annealed?
Passivate in nitric or citric acid after grinding/polishing for best corrosion resistance; hard-chrome or PVD coatings and mirror polishing are common for knives and bearings.
Can 440C Annealed be formed, bent or molded?
Cold forming is limited to gentle bending of annealed sheet; forge 1050–1150 °C and cool slowly with an immediate anneal to prevent quench cracks.
What is the maximum service temperature of 440C Annealed?
440C Annealed is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 440C Annealed?
Yes — 440C Annealed is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A276/A276M — Stainless Steel Bars and Shapes — ASTM (2017)
- GB/T 1220 (9Cr18Mo) — SAC (2007)
- EN 10088-3 / X105CrMo17 (1.4125) — CEN (2014)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- 440C Stainless Steel Product Data Sheet — AK Steel / Cleveland-Cliffs (2016)
- Machinery's Handbook machinability ratings — Industrial Press (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.