Stainless Steel 420F · temper · default condition
Stainless Steel 420F Annealed
Properties of the Annealed condition, compared with the other 420F tempers.
Standard stock condition for screw-machine work; machine here, then harden the finished part.
What is 420F Annealed?
420F Annealed is 420F in the Annealed temper — standard stock condition for screw-machine work; machine here, then harden the finished part. 420F Annealed has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 52% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 200 GPa (29 Msi). 420F Annealed has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 66% of stainless steel grades. It melts at 1,450°C (2,642 °F).
Advantages
- High electrical conductivity — 3.1 % IACS, better than 99% of stainless steel grades
- Easy to machine — 58/100, better than 97% of stainless steel grades
- Low embodied carbon — 3.4 kg CO₂/kg, better than 91% of stainless steel grades
- Conducts heat well — 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 88% of stainless steel grades
Limitations
- Difficult to weld — 12/100, worse than 99% of stainless steel grades
- Needs corrosion protection — 35/100, worse than 97% of stainless steel grades
- Hard to polish — 50/100, worse than 94% of stainless steel grades
- Limited ductility — 20%, worse than 79% of stainless steel grades
- Limited formability — 25/100, worse than 79% of stainless steel grades
420F Annealed properties
Typical room-temperature values for 420F Annealed — 14 properties are specific to this condition; the rest are grade-level values shared by every 420F temper. Each bar shows where the value sits among the stainless steel grades in FabDigit's library — further right is higher.
Physical3
420F Annealed has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 66% of stainless steel grades. It melts at 1,450°C (2,642 °F).
Mechanical13
420F Annealed has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 52% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
420F Annealed is rated for continuous service to 400°C (752 °F). It conducts heat at 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 88% of stainless steel grades. Thermal expansion is 10.3 µm/m·K (5.72 µin/in·°F).
Electrical3
420F Annealed conducts electricity at 3.1 % IACS, better than 99% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (35/100), worse than 97% of stainless steel grades.
Sustainability4
Producing a kilogram of 420F Annealed takes about 45 MJ of energy and emits 3.4 kg of CO₂ — less than 91% of stainless steel grades. Typical recycled content is 65%.
Manufacturability8
420F Annealed's machinability is good (58/100, better than 97% 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 420F tempers and conditions
420F is also supplied in 4 other conditions. The full side-by-side table is on the 420F overview.
- AnnealedDefaultStandard stock condition for screw-machine work; machine here, then harden the finished part.380 MPa yield · 220 HB
- Hardened & TemperedDefault hardened condition for cutting edges, valve stems and wear surfaces where maximum hardness and best corrosion behaviour of the hardened states are needed.1,480 MPa yield · 50 HRC
- Q&T 40-45 HRCUse when a little more toughness than the 50 HRC condition is required and corrosion exposure is mild.1,180 MPa yield · 43 HRC
- Q&T 28-32 HRCTough, machinable heat-treated condition for shafts and stems where hardness is secondary; corrosion resistance is the lowest of all conditions.800 MPa yield · 30 HRC
- Annealed Cold DrawnPick for tight-tolerance turned parts needing better surface finish, straightness and chip control than hot-rolled annealed bar.620 MPa yield · 25 HRC
Working with 420F Annealed
Is 420F easy to machine?
Excellent for a martensitic stainless — sulfides break chips; use sharp carbide, ~60–80 % of 12L14 speeds, and machine in the annealed state before hardening.
Can 420F be welded?
Not recommended: high carbon plus sulfur gives hot cracking and brittle martensite; if unavoidable, preheat 200–300 °C, use 309/410NiMo filler and temper immediately.
Can 420F be formed, bent or molded?
Cold forming limited to light heading or straightening in the annealed condition; hot work 1150–900 °C followed by slow cool and full anneal at 840–900 °C.
What surface finishes work on 420F?
Passivate per ASTM A967 (citric preferred, nitric can attack sulfides); accepts hard chrome, black oxide and PVD, but sulfide stringers prevent a defect-free mirror polish.
420F 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 |
|---|---|---|
| CJIS SUS420F allows 0.26–0.40 | 0.3 – 0.4 | 0.35 |
| Cr | 12 – 14 | 13 |
| Mn | ≤ 1.25 | 0.8 |
| Si | ≤ 1 | 0.5 |
| Sfree-machining addition; forms MnS stringers | ≥ 0.15 | 0.22 |
| P | ≤ 0.06 | 0.03 |
| Mooptional, at producer's discretion | ≤ 0.6 | — |
| Fe | balance | — |
420F Annealed — frequently asked
What is 420F Annealed used for?
420F Annealed is typically used for cutlery blanks, dental and surgical instruments, scissor and shear blades, valve stems and seats, spindles and shafts and wear pins and bushings. In short: free-machining martensitic stainless.
What is the yield strength of 420F Annealed?
420F Annealed has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 52% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is 420F Annealed easy to machine?
Reasonably — machinability is rated good (58/100, better than 97% of stainless steel grades). Excellent for a martensitic stainless — sulfides break chips; use sharp carbide, ~60–80 % of 12L14 speeds, and machine in the annealed state before hardening.
Can 420F Annealed be welded?
Not readily — weldability is rated not recommended (12/100). Not recommended: high carbon plus sulfur gives hot cracking and brittle martensite; if unavoidable, preheat 200–300 °C, use 309/410NiMo filler and temper immediately.
What surface finishes work on 420F Annealed?
Passivate per ASTM A967 (citric preferred, nitric can attack sulfides); accepts hard chrome, black oxide and PVD, but sulfide stringers prevent a defect-free mirror polish.
Can 420F Annealed be formed, bent or molded?
Cold forming limited to light heading or straightening in the annealed condition; hot work 1150–900 °C followed by slow cool and full anneal at 840–900 °C.
What is the maximum service temperature of 420F Annealed?
420F Annealed is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 420F Annealed?
Yes — 420F Annealed 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)
- JIS G 4303 — Stainless Steel Bars (SUS420F) — JSA (2021)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASTM A967/A967M — Chemical Passivation Treatments for Stainless Steel Parts — ASTM International (2017)
- Martensitic free-machining stainless bar datasheets (Sandvik / Ugitech / Outokumpu 4028-type) — various producers (2023)
- (SMM / Mysteel / 1688 ) — SMM / Mysteel (2025)
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.