Stainless Steel N690 QT-58-60HRC
Hardness band
QT-58-60HRC = hardened & tempered to 58–60 HRC
Default finished-blade condition: best balance of edge retention, toughness and stain resistance.
Values for the QT-58-60HRC condition
Other N690 tempers and conditions
N690 is listed in 5 conditions; see the grade overview at N690.
- Annealed
- SR
- QT-56-58HRC
- QT-58-60HRC
- QT-CRYO-60-62HRC
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault soft annealed bar/plate/strip (≤250 HB) | Stock condition for blade blanks and mould blocks: machine, grind and profile before hardening. | 460 | 780 | 14 | 235 HB | — |
Stress relieved | Intermediate step for large mould blocks or long blades to minimise distortion during subsequent hardening. | 480 | 800 | 13 | 22 HRC | — |
Hardened & tempered to 56–58 HRC | Tougher setting for thick blades, choppers and tools where chipping resistance matters more than edge retention. | 1,700 | 1,950 | 2 | 57 HRC | — |
QT-58-60HRCThis page Hardened & tempered to 58–60 HRC | Default finished-blade condition: best balance of edge retention, toughness and stain resistance. | 1,850 | 2,100 | 1.5 | 59 HRC | — |
Hardened + deep-freeze (cryo) + tempered, 60–62 HRC | Maximum hardness/edge retention with retained austenite transformed; choose for slicing edges and wear parts, accepting lower toughness. | 1,950 | 2,200 | 1 | 61 HRC | — |
What is N690 QT-58-60HRC?
N690 QT-58-60HRC is N690 heat treated to QT-58-60HRC — default finished-blade condition: best balance of edge retention, toughness and stain resistance. N690 QT-58-60HRC has a yield strength of 1,850 MPa (268 ksi) and a tensile strength of 2,100 MPa (305 ksi) — stronger than 100% of stainless steel grades. Elongation at break is 1.5% and the elastic modulus is 215 GPa (31.2 Msi). N690 QT-58-60HRC has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,380°C (2,516 °F). Annealed is the default condition FabDigit quotes; QT-58-60HRC is available on request or by drawing note.
Advantages
- High strength — 1,850 MPa (268 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 — 2.7 % IACS, better than 78% of stainless steel grades
Limitations
- Limited ductility — 1.5%, worse than 100% of stainless steel grades
- Limited service temperature — 200°C (392 °F), worse than 100% of stainless steel grades
- Difficult to machine — 6/100, worse than 100% of stainless steel grades
- Difficult to weld — 12/100, worse than 99% of stainless steel grades
- Limited formability — 22/100, worse than 82% of stainless steel grades
N690 QT-58-60HRC properties
Typical room-temperature values for N690 QT-58-60HRC; 15 are specific to this condition. Other listed values are N690 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
N690 QT-58-60HRC has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,380°C (2,516 °F).
Mechanical15
N690 QT-58-60HRC has a yield strength of 1,850 MPa (268 ksi) and a tensile strength of 2,100 MPa (305 ksi) — stronger than 100% of stainless steel grades. Elongation at break is 1.5% and the elastic modulus is 215 GPa (31.2 Msi).
Thermal6
N690 QT-58-60HRC is rated for continuous service to 200°C (392 °F). It conducts heat at 16 W/m·K (9.24 BTU/hr·ft·°F), better than 58% of stainless steel grades. Thermal expansion is 10.4 µm/m·K (5.78 µin/in·°F).
Electrical3
N690 QT-58-60HRC conducts electricity at 2.7 % IACS, better than 78% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (60/100), worse than 58% of stainless steel grades.
Sustainability4
Producing a kilogram of N690 QT-58-60HRC takes about 55 MJ of energy and emits 4.5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 45%.
Manufacturability7
N690 QT-58-60HRC's machinability is not recommended (6/100, worse than 100% of stainless steel grades); weldability not recommended (12/100); formability poor (22/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with N690 QT-58-60HRC
Is N690 easy to machine?
Machine only in the annealed state with rigid setups, sharp carbide or coated carbide and moderate speeds; after hardening use grinding, EDM or CBN only.
Can N690 be welded?
Essentially not weldable for structural purposes — high carbon causes brittle martensite and cracking; if unavoidable, preheat 250–350 °C, matching/austenitic filler and immediate temper.
Can N690 be formed, bent or molded?
Hot form 1050–850 °C with slow cooling and immediate soft anneal; cold forming limited to gentle bends of thin annealed strip.
What surface finishes work on N690?
Takes an excellent mirror polish after hardening; passivate or electropolish for best stain resistance, and PVD/DLC coatings must run below the tempering temperature.
N690 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 |
|---|---|---|
| C | 1.01 – 1.12 | 1.07 |
| Si | 0.25 – 0.55 | 0.4 |
| Mn | 0.25 – 0.55 | 0.4 |
| Cr | 16.5 – 17.5 | 17.3 |
| Moimproves pitting resistance and secondary carbide fineness | 0.9 – 1.3 | 1.1 |
| Vgrain refinement | 0.07 – 0.15 | 0.1 |
| Coraises matrix strength and tempering stability | 1.3 – 1.7 | 1.5 |
| Pimpurity | ≤ 0.03 | — |
| Simpurity | ≤ 0.03 | — |
| Fe | balance | — |
N690 QT-58-60HRC — frequently asked
What is N690 QT-58-60HRC used for?
N690 QT-58-60HRC is typically used for premium knife blades, diving knives and cutlery. In short: cobalt-alloyed 440C alternative; tougher than standard 440C; marine-grade blade steel.
What is the yield strength of N690 QT-58-60HRC?
N690 QT-58-60HRC has a typical yield strength of 1,850 MPa (268 ksi) and a tensile strength of 2,100 MPa (305 ksi) — stronger than 100% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is N690 QT-58-60HRC 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 rigid setups, sharp carbide or coated carbide and moderate speeds; after hardening use grinding, EDM or CBN only.
Can N690 QT-58-60HRC be welded?
Not readily — weldability is rated not recommended (12/100). Essentially not weldable for structural purposes — high carbon causes brittle martensite and cracking; if unavoidable, preheat 250–350 °C, matching/austenitic filler and immediate temper.
What surface finishes work on N690 QT-58-60HRC?
Takes an excellent mirror polish after hardening; passivate or electropolish for best stain resistance, and PVD/DLC coatings must run below the tempering temperature.
Can N690 QT-58-60HRC be formed, bent or molded?
Hot form 1050–850 °C with slow cooling and immediate soft anneal; cold forming limited to gentle bends of thin annealed strip.
What is the maximum service temperature of N690 QT-58-60HRC?
N690 QT-58-60HRC is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between N690 Annealed and N690-SR?
Annealed is the default condition — stock condition for blade blanks and mould blocks: machine, grind and profile before hardening. SR: intermediate step for large mould blocks or long blades to minimise distortion during subsequent hardening. Yield strength is 460 MPa in Annealed versus 480 MPa in SR.
Sources
- BÖHLER N690 Corrosion-resistant knife and tool steel — voestalpine BÖHLER Edelstahl (2021)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys (440C data) — ASM International (1990)
- ASTM A276 / A756 — Stainless Steel Bars and Shapes (Type 440C reference) — ASTM (2017)
- GB/T 1220 (9Cr18MoV comparison grade) — SAC (2007)
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.