Stainless Steel 420F · hardness band
Stainless Steel 420F Q&T 28-32 HRC
Properties of the Q&T 28-32 HRC condition, compared with the other 420F tempers.
Tough, machinable heat-treated condition for shafts and stems where hardness is secondary; corrosion resistance is the lowest of all conditions.
What is 420F Q&T 28-32 HRC?
420F Q&T 28-32 HRC is 420F heat treated to Q&T 28-32 HRC — tough, machinable heat-treated condition for shafts and stems where hardness is secondary; corrosion resistance is the lowest of all conditions. 420F Q&T 28-32 HRC has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 97% of stainless steel grades. Elongation at break is 16% and the elastic modulus is 200 GPa (29 Msi). 420F Q&T 28-32 HRC 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). Annealed is the default condition FabDigit quotes; Q&T 28-32 HRC is available on request or by drawing note.
Advantages
- High electrical conductivity — 3.1 % IACS, better than 99% of stainless steel grades
- High strength — 800 MPa (116 ksi), 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
- Needs corrosion protection — 25/100, worse than 100% of stainless steel grades
- Difficult to weld — 12/100, worse than 99% of stainless steel grades
- Hard to polish — 50/100, worse than 94% of stainless steel grades
- Limited ductility — 16%, worse than 88% of stainless steel grades
- Limited formability — 25/100, worse than 79% of stainless steel grades
420F Q&T 28-32 HRC properties
Typical room-temperature values for 420F Q&T 28-32 HRC — 12 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 Q&T 28-32 HRC 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 Q&T 28-32 HRC has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 97% of stainless steel grades. Elongation at break is 16% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
420F Q&T 28-32 HRC is rated for continuous service to 500°C (932 °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 Q&T 28-32 HRC conducts electricity at 3.1 % IACS, better than 99% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is poor (25/100), worse than 100% of stainless steel grades.
Sustainability4
Producing a kilogram of 420F Q&T 28-32 HRC 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 Q&T 28-32 HRC's machinability is fair (42/100, better than 79% of stainless steel grades); weldability not recommended (12/100); formability poor (25/100).
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 Q&T 28-32 HRC
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 Q&T 28-32 HRC — frequently asked
What is 420F Q&T 28-32 HRC used for?
420F Q&T 28-32 HRC 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 Q&T 28-32 HRC?
420F Q&T 28-32 HRC has a typical yield strength of 800 MPa (116 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 97% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is 420F Q&T 28-32 HRC easy to machine?
Not especially — machinability is rated fair (42/100, better than 79% 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 Q&T 28-32 HRC 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 Q&T 28-32 HRC?
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 Q&T 28-32 HRC 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 Q&T 28-32 HRC?
420F Q&T 28-32 HRC is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 420F Q&T 28-32 HRC?
Yes — 420F Q&T 28-32 HRC 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.