Stainless Steel 440F · heat-treated state

Stainless Steel 440F Hardened & Tempered

Properties of the Hardened & Tempered condition, compared with the other 440F tempers.

Standard service condition: choose for maximum hardness, wear resistance and the best corrosion resistance this grade can offer.

CNC machiningStandard cost $$

Quote a part in 440F Hardened & Tempered 440F overview

What is 440F Hardened & Tempered?

440F Hardened & Tempered is 440F heat treated to Hardened & Tempered — standard service condition: choose for maximum hardness, wear resistance and the best corrosion resistance this grade can offer. 440F Hardened & Tempered has a yield strength of 1,720 MPa (249 ksi) and a tensile strength of 1,860 MPa (270 ksi) — stronger than 100% of stainless steel grades. Elongation at break is 3% and the elastic modulus is 200 GPa (29 Msi). 440F Hardened & Tempered has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,370°C (2,498 °F). Annealed is the default condition FabDigit quotes; Hardened & Tempered is available on request or by drawing note.

Advantages

High strength — 1,720 MPa (249 ksi), better than 100% of stainless steel grades
Low embodied carbon — 3.4 kg CO₂/kg, better than 91% 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

Limitations

Limited ductility — 3%, worse than 100% of stainless steel grades
Difficult to machine — 12/100, worse than 100% of stainless steel grades
Limited formability — 2/100, worse than 100% of stainless steel grades
Limited service temperature — 250°C (482 °F), worse than 99% of stainless steel grades
Difficult to weld — 12/100, worse than 99% of stainless steel grades

440F Hardened & Tempered properties

Typical room-temperature values for 440F Hardened & Tempered — 18 properties are specific to this condition; the rest are grade-level values shared by every 440F temper. Each bar shows where the value sits among the stainless steel grades in FabDigit's library — further right is higher.

Physical3

440F Hardened & Tempered has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,370°C (2,498 °F).

Density7.7 g/cm³0.28 lb/in³

Melting Point (Solidus)1,370°C2,498 °F

Liquidus Temperature1,425°C2,597 °F

Mechanical15

440F Hardened & Tempered has a yield strength of 1,720 MPa (249 ksi) and a tensile strength of 1,860 MPa (270 ksi) — stronger than 100% of stainless steel grades. Elongation at break is 3% and the elastic modulus is 200 GPa (29 Msi).

Elastic (Young's) Modulus200 GPa29 Msi

Shear Modulus77 GPa11.2 Msi

Bulk Modulus160 GPa23.2 Msi

Poisson's Ratio0.28

Tensile Strength (Ultimate)1,860 MPa270 ksi

Yield Strength (0.2% offset)1,720 MPa249 ksi

Elongation at Break3%

Reduction in Area6%

Compressive Strength1,900 MPa276 ksi

Shear Strength1,100 MPa160 ksi

Fatigue Strength (Endurance Limit)750 MPa109 ksi

Charpy V-Notch Impact (RT)6 J4.4 ft·lbf

Hardness, Brinell580 HB

Hardness, Rockwell B96 HRB

Hardness, Vickers620 HV

Thermal6

440F Hardened & Tempered is rated for continuous service to 250°C (482 °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).

Thermal Conductivity24.2 W/m·K14 BTU/hr·ft·°F

Specific Heat Capacity460 J/kg·K0.11 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)10.2 µm/m·K5.7 µin/in·°F

Latent Heat of Fusion270 J/g116 BTU/lb

Max Service Temperature (continuous)250°C482 °F

Min Service Temperature-30°C-22 °F

Electrical3

440F Hardened & Tempered conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.

Electrical Conductivity2.9 % IACS

Electrical Resistivity6×10⁻⁷ Ω·m23.6 µΩ·in

Magnetic Responseferromagnetic

Chemical & Environmental3

Corrosion resistance is fair (42/100), worse than 90% of stainless steel grades.

Galvanic Potential (seawater, vs SCE)-0.25 V

Corrosion ResistanceFair42/100

Chemical Resistance SummaryAdequate in fresh water, mild atmospheres, petroleum products, alcohols and dilute organic acids when fully hardened and passivated; attacked by chlorides, seawater, acids and steam, and the MnS stringers act as pitting initiation sites, so it is clearly inferior to 440C and to austenitic 304/316.

Sustainability4

Producing a kilogram of 440F Hardened & Tempered takes about 53 MJ of energy and emits 3.4 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 40%.

Embodied Energy (primary production)53 MJ/kg22,786 BTU/lb

Embodied Carbon (primary production)3.4 kg CO₂/kg

Embodied Water90 L/kg10.8 gal/lb

Typical Recycled Content40%

Manufacturability6

440F Hardened & Tempered's machinability is not recommended (12/100, worse than 100% of stainless steel grades); weldability not recommended (12/100); formability not recommended (2/100).

MachinabilityNot recommended12/100

Machinability Rating (AISI 1212 = 100 %)10%

WeldabilityNot recommended12/100

Formability (cold)Not recommended2/100

Brazeability / SolderabilityFair40/100

PolishabilityGood60/100

Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.

Other 440F tempers and conditions

440F is also supplied in 3 other conditions. The full side-by-side table is on the 440F overview.

AnnealedDefaultStock condition for high-volume screw-machine work; parts are machined soft then hardened and tempered.415 MPa yield · 255 HB
Hardened & TemperedStandard service condition: choose for maximum hardness, wear resistance and the best corrosion resistance this grade can offer.1,720 MPa yield · 56 HRC
Q&T 48-52 HRCUse when a little more toughness and dimensional stability is needed and peak hardness/corrosion resistance can be traded away.1,480 MPa yield · 50 HRC
ACDPick for close-tolerance, bright-finish bar feeding CNC lathes when a slightly higher as-machined strength is acceptable.620 MPa yield · 285 HB

Working with 440F Hardened & Tempered

Is 440F easy to machine?

Best machining of the 440 family — run annealed with rigid setups, positive-rake carbide, moderate speeds and heavy soluble-oil coolant; expect abrasive wear from Cr-carbides and grind after hardening.

Can 440F be welded?

Not recommended: high carbon plus high sulfur cause hot cracking and hard, brittle HAZ; if unavoidable, preheat 200–300 °C, use 309/310 filler and anneal immediately.

Can 440F be formed, bent or molded?

Cold forming is essentially limited to light straightening; hot work 1150→900 °C followed by slow cooling and a full anneal to avoid quench cracks.

What surface finishes work on 440F?

Harden, temper and passivate (nitric or citric) for usable corrosion resistance; hard chrome or electroless nickel is common for wear/corrosion duty, and sulfide stringers keep it from taking a true mirror polish.

440F 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 Cr-carbides for hardness/wear	0.95 – 1.2	1.05
Cr	16 – 18	17
Mn	≤ 1.25	0.8
Si	≤ 1	0.5
Sfree-machining addition (MnS); Se-bearing 440F Se variant substitutes ≥0.15 % Se	≥ 0.15	0.2
P	≤ 0.06	0.03
Mooptional; may be added to aid machinability/hardenability	≤ 0.6	0.4
Fe	balance	—

440F Hardened & Tempered — frequently asked

What is 440F Hardened & Tempered used for?

440F Hardened & Tempered is typically used for cutlery, surgical instruments and knife blanks. In short: free-machining cutlery stainless.

What is the yield strength of 440F Hardened & Tempered?

440F Hardened & Tempered has a typical yield strength of 1,720 MPa (249 ksi) and a tensile strength of 1,860 MPa (270 ksi) — stronger than 100% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.

Is 440F Hardened & Tempered easy to machine?

Not especially — machinability is rated not recommended (12/100, worse than 100% of stainless steel grades). Best machining of the 440 family — run annealed with rigid setups, positive-rake carbide, moderate speeds and heavy soluble-oil coolant; expect abrasive wear from Cr-carbides and grind after hardening.

Can 440F Hardened & Tempered be welded?

Not readily — weldability is rated not recommended (12/100). Not recommended: high carbon plus high sulfur cause hot cracking and hard, brittle HAZ; if unavoidable, preheat 200–300 °C, use 309/310 filler and anneal immediately.

What surface finishes work on 440F Hardened & Tempered?

Can 440F Hardened & Tempered be formed, bent or molded?

Cold forming is essentially limited to light straightening; hot work 1150→900 °C followed by slow cooling and a full anneal to avoid quench cracks.

What is the maximum service temperature of 440F Hardened & Tempered?

440F Hardened & Tempered is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.

What is the difference between 440F Annealed and 440F-ACD?

Annealed is the default condition — stock condition for high-volume screw-machine work; parts are machined soft then hardened and tempered. ACD: pick for close-tolerance, bright-finish bar feeding CNC lathes when a slightly higher as-machined strength is acceptable. Yield strength is 415 MPa in Annealed versus 620 MPa in ACD.

Can FabDigit make parts in 440F Hardened & Tempered?

Yes — 440F Hardened & Tempered is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.

Sources

ASTM A582/A582M — Free-Machining Stainless Steel Bars — ASTM International (2021)
EN 10088-3 (X70CrMo15 / 1.4109 related martensitic grades) — CEN (2014)
ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
ASM Specialty Handbook — Stainless Steels — ASM International (1994)
Martensitic free-machining stainless bar datasheets (440C/440F class) — Various bar producers (2023)

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.