Stainless Steel AUS-8
AUS-8 is a Japanese (Aichi Steel) vanadium-modified martensitic stainless steel in the 420/440 group (UNS S42000) with about 0.75 % carbon.
Reference datasheet — AUS-8 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the Annealed condition
AUS-8 tempers and conditions
AUS-8 is supplied in 5 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault mill soft-annealed strip/plate for blanking and machining | The as-supplied condition for knife blanks: soft enough to stamp, laser-cut, drill and grind before heat treatment. | 450 | 760 | 18 | 225 HB | — |
Cold rolled | Precision-rolled thin strip supplied slightly harder than full anneal for clean stamping of thin blades and razor blanks. | 650 | 900 | 10 | 28 HRC | 3 % IACS |
hardened and tempered for maximum toughness | Choose for choppers, machetes, dive knives and thick-spine tools where chip resistance beats edge holding. | 1,600 | 1,900 | 3 | 56 HRC | — |
standard knife hardening (≈1050–1070 °C austenitize, 180–200 °C temper) | The mainstream production-knife condition: best balance of edge retention, toughness and easy field sharpening. | 1,750 | 2,050 | 2 | 58 HRC | — |
Q&T + cryogenic 59–61 HRC | Sub-zero treatment converts retained austenite for peak hardness and edge stability; toughness and corrosion margin drop, so keep edges thicker. | 1,850 | 2,150 | 1.5 | 60 HRC | — |
What is AUS-8?
AUS-8 is a Japanese (Aichi Steel) vanadium-modified martensitic stainless steel in the 420/440 group (UNS S42000) with about 0.75 % carbon. It is chosen for a balance of toughness, edge retention and easy resharpening in mid-range blades, and is supplied as annealed or cold-rolled strip and flat bar, hardened to 55-57, 57-59 or 59-61 HRC with a cryogenic step. Annealed properties are 450 MPa yield, 760 MPa tensile, 18 % elongation and 225 HB, with formability 35, machinability 40 and a 400 °C service ceiling. AUS-10 gives more hardness and wear resistance at the cost of toughness. AUS-8 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F). AUS-8 has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 70% of stainless steel grades. Elongation at break is 18% and the elastic modulus is 200 GPa (29 Msi).
What is AUS-8 used for?
- mid-range production knives
- multi-tools
- kitchen cutlery
Advantages
- High electrical conductivity — 3 % IACS, better than 95% 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
- Difficult to weld — 20/100, worse than 95% of stainless steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 88% of stainless steel grades
- Limited ductility — 18%, worse than 83% of stainless steel grades
- Needs corrosion protection — 48/100, worse than 80% of stainless steel grades
- Limited service temperature — 400°C (752 °F), worse than 78% of stainless steel grades
AUS-8 properties
Typical room-temperature values for AUS-8-Annealed; bars are the position among stainless steel grades.
Physical3
AUS-8 has a density of 7.75 g/cm³ (0.28 lb/in³), lighter than 65% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
AUS-8 has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 70% of stainless steel grades. Elongation at break is 18% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
AUS-8 is rated for continuous service to 400°C (752 °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 10.4 µm/m·K (5.78 µin/in·°F).
Electrical3
AUS-8 conducts electricity at 3 % IACS, better than 95% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (48/100), worse than 80% of stainless steel grades.
Sustainability4
Producing a kilogram of AUS-8 takes about 53 MJ of energy and emits 5 kg of CO₂ — less than 67% of stainless steel grades. Typical recycled content is 35%.
Manufacturability8
AUS-8's machinability is fair (40/100, better than 72% of stainless steel grades); weldability poor (20/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. AUS-8 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with AUS-8
Is AUS-8 easy to machine?
Machine, drill and profile only in the annealed state with sharp carbide and rigid setups (~45 % of 1212); once hardened, work by CBN/diamond grinding or EDM only.
Can AUS-8 be welded?
Poor weldability — 0.75 % C martensitic steel cracks readily; if unavoidable preheat 250–300 °C, use 309/312 filler and temper immediately, expect a soft/brittle HAZ.
Can AUS-8 be formed, bent or molded?
Blank, laser or waterjet cut and lightly bend in the annealed condition; hot forge 1050–1150 °C, never below ~900 °C, and always slow-cool/anneal after forging.
AUS-8 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 | 0.7 – 0.75 | 0.73 |
| Si | ≤ 1 | 0.4 |
| Mn | ≤ 0.5 | 0.4 |
| P | ≤ 0.04 | |
| S | ≤ 0.03 | |
| Niaustenite stabiliser, aids toughness | ≤ 0.49 | 0.3 |
| Cr | 13 – 14.5 | 13.75 |
| Mo | 0.1 – 0.31 | 0.2 |
| Vgrain refinement, fine carbides | 0.1 – 0.26 | 0.18 |
| Fe | balance |
What surface finishes work on AUS-8?
Grind, then passivate (citric or nitric per ASTM A967) after hardening; takes a fine satin or mirror polish, and accepts stonewash, bead blast, black oxide or PVD/DLC coatings applied below the tempering temperature.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel AUS-8 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- S42000
How much does AUS-8 cost?
AUS-8 is a premium-cost stainless steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
AUS-8 — frequently asked
What is AUS-8 used for?
AUS-8 is typically used for mid-range production knives, multi-tools and kitchen cutlery. In short: easy-sharpening mid-range blade steel; best formability in family; tougher than 440C-class.
What is the yield strength of AUS-8?
AUS-8 has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 70% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is AUS-8 easy to machine?
Not especially — machinability is rated fair (40/100, better than 72% of stainless steel grades). Machine, drill and profile only in the annealed state with sharp carbide and rigid setups (~45 % of 1212); once hardened, work by CBN/diamond grinding or EDM only.
Can AUS-8 be welded?
Not readily — weldability is rated poor (20/100). Poor weldability — 0.75 % C martensitic steel cracks readily; if unavoidable preheat 250–300 °C, use 309/312 filler and temper immediately, expect a soft/brittle HAZ.
What surface finishes work on AUS-8?
Grind, then passivate (citric or nitric per ASTM A967) after hardening; takes a fine satin or mirror polish, and accepts stonewash, bead blast, black oxide or PVD/DLC coatings applied below the tempering temperature.
Can AUS-8 be formed, bent or molded?
Blank, laser or waterjet cut and lightly bend in the annealed condition; hot forge 1050–1150 °C, never below ~900 °C, and always slow-cool/anneal after forging.
What is the maximum service temperature of AUS-8?
AUS-8 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.
What is the difference between AUS-8 Annealed and AUS-8-CR?
Annealed is the default condition — the as-supplied condition for knife blanks: soft enough to stamp, laser-cut, drill and grind before heat treatment. CR: precision-rolled thin strip supplied slightly harder than full anneal for clean stamping of thin blades and razor blanks. Yield strength is 450 MPa in Annealed versus 650 MPa in CR.
How much does AUS-8 cost?
AUS-8 is a premium-cost stainless steel ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- AUS series stainless knife steel (AUS-6 / AUS-8 / AUS-10) data — Aichi Steel Corporation (2020)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys (martensitic stainless) — ASM International (1990)
- JIS G 4303 / G 4305 — Stainless steel bars and cold-rolled plates, sheets and strip — JSA (2021)
- ASTM A967 — Chemical Passivation Treatments for Stainless Steel Parts — ASTM (2017)
- Machinery's Handbook, machinability ratings for stainless steels — Industrial Press (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.