Stainless Steel 420HC-QT58
Heat-treated state
AISI/SAE 420HC
QT58 = hardened and tempered to maximum hardness 56–58 HRC
Maximum edge retention and wear resistance for premium 420HC blades and wear parts; accept low toughness and grinding-only machining.
Values for the QT58 condition
Other 420HC tempers and conditions
420HC is listed in 8 conditions; see the grade overview at 420HC.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard stocked condition for bar, plate and strip that will be blanked, machined or ground and then hardened by the user. | 345 | 660 | 22 | 195 HB | — |
Cold rolled and annealed strip/coil | Pick for stamped or laser-cut blade and cutlery blanks where flat, clean, dimensionally tight soft strip is needed. | 380 | 690 | 20 | 15 HRC | 3.1 % IACS |
Cold drawn | Choose for as-supplied strength and straightness in machined shafts, pins and screw-machine parts that may not be hardened. | 620 | 790 | 12 | 235 HB | — |
Hardened and tempered to 42–46 HRC | Use where shock loading or bending matters more than edge holding — machetes, large tools, valve and pump parts; note the higher temper reduces corrosion resistance. | 1,200 | 1,450 | 8 | 44 HRC | — |
Hardened and tempered to 48–51 HRC | Balanced condition for scissors, shears, surgical and dental instruments needing some toughness with decent wear resistance. | 1,400 | 1,700 | 5 | 50 HRC | — |
Hardened and low-temperature tempered to 52–55 HRC | Common production knife hardness — good edge retention with enough toughness for folding and kitchen blades. | 1,520 | 1,860 | 3 | 54 HRC | — |
QT58This page Hardened and tempered to maximum hardness 56–58 HRC | Maximum edge retention and wear resistance for premium 420HC blades and wear parts; accept low toughness and grinding-only machining. | 1,650 | 1,980 | 2 | 57 HRC | — |
Stress relieved | Knife-industry route: quench, sub-zero soak to convert retained austenite, then low temper — slightly higher and more uniform hardness with better dimensional stability than plain Q&T. | 1,650 | 2,020 | 2 | 58 HRC | 2.9 % IACS |
What is 420HC-QT58?
420HC-QT58 is 420HC heat treated to QT58 — maximum edge retention and wear resistance for premium 420HC blades and wear parts; accept low toughness and grinding-only machining. 420HC-QT58 has a yield strength of 1,650 MPa (239 ksi) and a tensile strength of 1,980 MPa (287 ksi) — stronger than 100% of stainless steel grades. Elongation at break is 2% and the elastic modulus is 200 GPa (29 Msi). 420HC-QT58 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,450°C (2,642 °F). A is the default condition FabDigit quotes; QT58 is available on request or by drawing note.
Advantages
- High strength — 1,650 MPa (239 ksi), better than 100% of stainless steel grades
- Polishes to a fine finish — 88/100, better than 100% of stainless steel grades
- High electrical conductivity — 3.1 % IACS, better than 99% of stainless steel grades
- Low embodied carbon — 3 kg CO₂/kg, better than 97% of stainless steel grades
- Conducts heat well — 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades
Limitations
- Limited ductility — 2%, worse than 100% of stainless steel grades
- Limited service temperature — 150°C (302 °F), worse than 100% of stainless steel grades
- Difficult to machine — 6/100, worse than 100% of stainless steel grades
- Limited formability — 2/100, worse than 100% of stainless steel grades
- Difficult to weld — 30/100, worse than 88% of stainless steel grades
420HC-QT58 properties
Typical room-temperature values for 420HC-QT58; 16 are specific to this condition. Other listed values are 420HC reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
420HC-QT58 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,450°C (2,642 °F).
Mechanical14
420HC-QT58 has a yield strength of 1,650 MPa (239 ksi) and a tensile strength of 1,980 MPa (287 ksi) — stronger than 100% of stainless steel grades. Elongation at break is 2% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
420HC-QT58 is rated for continuous service to 150°C (302 °F). It conducts heat at 24.9 W/m·K (14.4 BTU/hr·ft·°F), better than 87% of stainless steel grades. Thermal expansion is 10.3 µm/m·K (5.72 µin/in·°F).
Electrical3
420HC-QT58 conducts electricity at 3.1 % IACS, better than 99% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (52/100), worse than 76% of stainless steel grades.
Sustainability4
Producing a kilogram of 420HC-QT58 takes about 46 MJ of energy and emits 3 kg of CO₂ — less than 88% of stainless steel grades. Typical recycled content is 45%.
Manufacturability6
420HC-QT58's machinability is not recommended (6/100, worse than 100% of stainless steel grades); weldability poor (30/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 420HC-QT58
Is 420HC easy to machine?
Machine only in the annealed state with sharp, rigid, positive-rake carbide tooling and flood coolant (≈45 % of 1212); hardened 420HC above ~45 HRC is effectively a grinding/EDM job.
Can 420HC be welded?
Poor weldability — air-hardening HAZ cracks readily; if unavoidable, preheat 200–300 °C, use 410/309L filler and temper or fully re-anneal afterwards.
Can 420HC be formed, bent or molded?
Blank, bend and coin in the soft annealed strip condition with generous radii; harden after forming, and expect ~0.05–0.15 % dimensional growth plus warping during quench.
What surface finishes work on 420HC?
Grinds and mirror-polishes very well when hardened; always passivate (nitric/citric) after grinding, and avoid tempering above ~400 °C or chloride-bearing pickles which drop corrosion resistance.
420HC 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 variant of S42000 (base 420 is ≥0.15 C) | 0.4 – 0.5 | 0.45 |
| Cr | 12 – 14 | 13 |
| Mn | ≤ 1 | 0.4 |
| Si | ≤ 1 | 0.4 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Niresidual/optional, mill practice | ≤ 0.75 | 0.25 |
| Mooptional residual in some producer variants | ≤ 0.5 | — |
| Voptional grain refiner in some 420HC melts | ≤ 0.3 | — |
| Fe | balance | — |
420HC-QT58 — frequently asked
What is 420HC-QT58 used for?
420HC-QT58 is typically used for pocket knives, fixed-blade knives and cutlery. In short: harder than standard 420; low-cost stainless blade steel; form soft, harden after.
What is the yield strength of 420HC-QT58?
420HC-QT58 has a typical yield strength of 1,650 MPa (239 ksi) and a tensile strength of 1,980 MPa (287 ksi) — stronger than 100% of stainless steel grades. Strength varies by condition: see the 8 listed tempers.
Is 420HC-QT58 easy to machine?
Not especially — machinability is rated not recommended (6/100, worse than 100% of stainless steel grades). Machine only in the annealed state with sharp, rigid, positive-rake carbide tooling and flood coolant (≈45 % of 1212); hardened 420HC above ~45 HRC is effectively a grinding/EDM job.
Can 420HC-QT58 be welded?
Not readily — weldability is rated poor (30/100). Poor weldability — air-hardening HAZ cracks readily; if unavoidable, preheat 200–300 °C, use 410/309L filler and temper or fully re-anneal afterwards.
What surface finishes work on 420HC-QT58?
Grinds and mirror-polishes very well when hardened; always passivate (nitric/citric) after grinding, and avoid tempering above ~400 °C or chloride-bearing pickles which drop corrosion resistance.
Can 420HC-QT58 be formed, bent or molded?
Blank, bend and coin in the soft annealed strip condition with generous radii; harden after forming, and expect ~0.05–0.15 % dimensional growth plus warping during quench.
What is the maximum service temperature of 420HC-QT58?
420HC-QT58 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 420HC-A and 420HC-QT58?
A is the default condition — standard stocked condition for bar, plate and strip that will be blanked, machined or ground and then hardened by the user. QT58: maximum edge retention and wear resistance for premium 420HC blades and wear parts; accept low toughness and grinding-only machining. Yield strength is 345 MPa in A versus 1,650 MPa in QT58.
Sources
- ASTM A276/A276M — Stainless Steel Bars and Shapes — ASTM International (2023)
- ASTM A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip — ASTM International (2023)
- GB/T 1220 / GB/T 3280 (4Cr13 / 20Cr13-40Cr13 series) (2016)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- 420HC / 420 modified cutlery steel datasheets (Crucible/Latrobe, Sandvik, Aperam class data) — various mills (2022)
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.