Stainless Steel ATS-34 QT 55-57HRC
Hardness band
Choose for large blades, chopping tools and structural parts needing higher chipping resistance; the ~300-350 °C temper trades some edge retention for toughness.
Values for the QT 55-57HRC condition
Other ATS-34 tempers and conditions
ATS-34 is listed in 5 conditions; see the grade overview at ATS-34.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault spheroidize annealed bar/plate/strip (mill supply condition) | Order in the spheroidize annealed mill condition (220 HB, 760 MPa) for blade blanks and machining, then harden and temper after cutting to reach final service hardness. | 450 | 760 | 15 | 220 HB | — |
QT 55-57HRCThis page austenitize ~1040–1060 °C, oil/plate quench, temper ~300–350 °C | Choose for large blades, chopping tools and structural parts needing higher chipping resistance; the ~300-350 °C temper trades some edge retention for toughness. | 1,650 | 1,850 | 3 | 56 HRC | — |
Q&T secondary-hardened 58–59 HRC | Specify for tooling and valve parts working at 150-400 °C; the twice-repeated 510-540 °C secondary-hardening temper gives high temper stability with slightly lower corrosion resistance. | 1,800 | 1,950 | 2 | 59 HRC | 2.7 % IACS |
austenitize ~1050–1070 °C, quench, temper ~180–220 °C | Pick as the default blade heat treatment: austenitizing near 1050-1070 °C with a ~180-220 °C temper gives the best balance of hardness, edge retention and toughness. | 1,850 | 2,000 | 2 | 59 HRC | — |
Q&T + cryogenic 60–62 HRC | Use when maximum hardness and edge holding are the goal: the -75 to -196 °C sub-zero step transforms retained austenite, at the cost of toughness and machinability. | 1,950 | 2,100 | 1.5 | 61 HRC | — |
What is ATS-34 QT 55-57HRC?
ATS-34 QT 55-57HRC is ATS-34 heat treated to QT 55-57HRC — choose for large blades, chopping tools and structural parts needing higher chipping resistance; the ~300-350 °C temper trades some edge retention for toughness. ATS-34 QT 55-57HRC has a yield strength of 1,650 MPa (239 ksi) and a tensile strength of 1,850 MPa (268 ksi) — stronger than 100% of stainless steel grades. Elongation at break is 3% and the elastic modulus is 200 GPa (29 Msi). ATS-34 QT 55-57HRC has a density of 7.78 g/cm³ (0.281 lb/in³), lighter than 57% of stainless steel grades. It melts at 1,370°C (2,498 °F). Annealed is the default condition FabDigit quotes; QT 55-57HRC 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 — 85/100, better than 97% of stainless steel grades
- High electrical conductivity — 2.9 % IACS, better than 87% of stainless steel grades
- Conducts heat well — 24 W/m·K (13.9 BTU/hr·ft·°F), better than 81% of stainless steel grades
Limitations
- Limited ductility — 3%, worse than 100% of stainless steel grades
- Difficult to machine — 8/100, worse than 100% of stainless steel grades
- Limited service temperature — 250°C (482 °F), worse than 99% of stainless steel grades
- Difficult to weld — 20/100, worse than 95% of stainless steel grades
- Needs corrosion protection — 48/100, worse than 80% of stainless steel grades
ATS-34 QT 55-57HRC properties
Typical room-temperature values for ATS-34 QT 55-57HRC; 13 are specific to this condition. Other listed values are ATS-34 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
ATS-34 QT 55-57HRC has a density of 7.78 g/cm³ (0.281 lb/in³), lighter than 57% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Mechanical12
ATS-34 QT 55-57HRC has a yield strength of 1,650 MPa (239 ksi) and a tensile strength of 1,850 MPa (268 ksi) — stronger than 100% of stainless steel grades. Elongation at break is 3% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
ATS-34 QT 55-57HRC is rated for continuous service to 250°C (482 °F). It conducts heat at 24 W/m·K (13.9 BTU/hr·ft·°F), better than 81% of stainless steel grades. Thermal expansion is 10.2 µm/m·K (5.67 µin/in·°F).
Electrical3
ATS-34 QT 55-57HRC conducts electricity at 2.9 % IACS, better than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (48/100), worse than 80% of stainless steel grades.
Sustainability4
Producing a kilogram of ATS-34 QT 55-57HRC takes about 55 MJ of energy and emits 5 kg of CO₂ — more than 50% of stainless steel grades. Typical recycled content is 25%.
Manufacturability8
ATS-34 QT 55-57HRC's machinability is not recommended (8/100, worse than 100% of stainless steel grades); weldability poor (20/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ATS-34 QT 55-57HRC
Is ATS-34 easy to machine?
Machine only in the annealed condition: low speed, heavy feed, rigid clamping and coated carbide or powder high-speed steel tooling. Once hardened, use grinding or EDM only.
Can ATS-34 be welded?
Fusion welding is not recommended, as high-carbon martensite cold-cracks readily. If unavoidable, preheat 200-300 °C and temper immediately after welding, or switch to brazing or mechanical joining.
Can ATS-34 be formed, bent or molded?
Cold formability is very poor. Forge in the range 1100 °C down to 900 °C, then cool slowly and spheroidize anneal to prevent cracking.
What surface finishes work on ATS-34?
The fine grain structure polishes to a mirror. Passivate after heat treatment to restore the passive film; DLC/PVD and satin brushed finishes are options, and anodizing does not apply.
ATS-34 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 for M7C3/M6C carbides | 1 – 1.1 | 1.05 |
| Cr | 13 – 14.5 | 14 |
| Mowear resistance + pitting resistance | 3.75 – 4.25 | 4 |
| Mn | ≤ 0.5 | 0.4 |
| Si | ≤ 0.5 | 0.35 |
| Pimpurity | ≤ 0.03 | — |
| Simpurity | ≤ 0.03 | — |
| Fe | balance | — |
ATS-34 QT 55-57HRC — frequently asked
What is ATS-34 QT 55-57HRC used for?
ATS-34 QT 55-57HRC is typically used for premium knife blades, kitchen cutlery, folding knife blades, custom and semi-custom blade blanks, hardened wear inserts and edges and hunting and outdoor knives. In short: fine-grained 154CM analogue; strong hardenability, 62 HRC; not for welded assemblies.
What is the yield strength of ATS-34 QT 55-57HRC?
ATS-34 QT 55-57HRC has a typical yield strength of 1,650 MPa (239 ksi) and a tensile strength of 1,850 MPa (268 ksi) — stronger than 100% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is ATS-34 QT 55-57HRC easy to machine?
Not especially — machinability is rated not recommended (8/100, worse than 100% of stainless steel grades). Machine only in the annealed condition: low speed, heavy feed, rigid clamping and coated carbide or powder high-speed steel tooling. Once hardened, use grinding or EDM only.
Can ATS-34 QT 55-57HRC be welded?
Not readily — weldability is rated poor (20/100). Fusion welding is not recommended, as high-carbon martensite cold-cracks readily. If unavoidable, preheat 200-300 °C and temper immediately after welding, or switch to brazing or mechanical joining.
What surface finishes work on ATS-34 QT 55-57HRC?
The fine grain structure polishes to a mirror. Passivate after heat treatment to restore the passive film; DLC/PVD and satin brushed finishes are options, and anodizing does not apply.
Can ATS-34 QT 55-57HRC be formed, bent or molded?
Cold formability is very poor. Forge in the range 1100 °C down to 900 °C, then cool slowly and spheroidize anneal to prevent cracking.
What is the maximum service temperature of ATS-34 QT 55-57HRC?
ATS-34 QT 55-57HRC 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.
Sources
- ATS-34 martensitic stainless knife steel data — Hitachi Metals (Proterial) (2019)
- 154CM / CPM 154 datasheet — Crucible Industries (2018)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASTM A276 / UNS S44004 (440C) related martensitic stainless requirements — ASTM (2017)
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.