Steel M34
AISI/SAE M34 · UNS T11334
M34 (UNS T11334) is a cobalt-alloyed molybdenum high-speed steel balanced for toughness together with elevated-temperature wear resistance in demanding cutting tools.
Reference datasheet — M34 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 A condition
M34 tempers and conditions
M34 is supplied in 5 conditions, soft to hard. A 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 |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard supply condition for machining tool blanks before hardening. | 560 | 880 | 22 | 235 HB | — |
Cold drawn / ground annealed bar | Choose for close-tolerance ground drill/tap blanks that will be hardened after fluting. | 700 | 950 | 14 | 25 HRC | 3.2 % IACS |
HT + surface treated | Finished-tool condition where a hard, low-friction surface layer is added to the hardened core for higher wear and galling resistance. | 2,050 | 2,300 | 0 | 65 HRC | 3 % IACS |
HT 66–68 HRC | Pick for maximum red hardness and wear life on light-feed cutting of high-strength or abrasive materials, at the cost of toughness. | 2,150 | 2,400 | 0 | 67 HRC | 3 % IACS |
HT 64–66 HRC | General-purpose hardened condition for drills, taps, end mills and broaches with a good hardness/toughness balance. | 2,200 | 0.5 | 65 HRC | 24 W/m·K |
What is M34?
M34 (UNS T11334) is a cobalt-alloyed molybdenum high-speed steel balanced for toughness together with elevated-temperature wear resistance in demanding cutting tools. It is supplied annealed or cold-drawn annealed as bar and tool blanks and hardened to 65 or 67 HRC, with nitrided options. Annealed properties are 880 MPa tensile, 560 MPa yield, 22 % elongation, 235 HB and 217 GPa modulus, with service to 550 °C, the highest of the M-series grades listed here. Cobalt raises cost and lowers toughness against M2, there is no corrosion resistance, and fusion welding is limited to repair; M33 is the closest alternative. M34 has a density of 8.03 g/cm³ (0.29 lb/in³), heavier than 96% of steel grades. It melts at 1,240°C (2,264 °F). M34 has a yield strength of 560 MPa (81.2 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 73% of steel grades. Elongation at break is 22% and the elastic modulus is 217 GPa (31.5 Msi).
What is M34 used for?
- Cutting tools for tough alloys
- Milling cutters
- Drills for high-temp alloys
Advantages
- High service temperature — 550°C (1,022 °F), better than 95% of steel grades
Limitations
- High embodied carbon — 5.6 kg CO₂/kg, worse than 98% of steel grades
- Limited formability — 10/100, worse than 95% of steel grades
- Poor heat conductor — 22 W/m·K (12.7 BTU/hr·ft·°F), worse than 93% of steel grades
- Difficult to weld — 15/100, worse than 91% of steel grades
- Low electrical conductivity — 3.2 % IACS, worse than 87% of steel grades
M34 properties
Typical room-temperature values for M34-A; bars are the position among steel grades.
Physical3
M34 has a density of 8.03 g/cm³ (0.29 lb/in³), heavier than 96% of steel grades. It melts at 1,240°C (2,264 °F).
Mechanical14
M34 has a yield strength of 560 MPa (81.2 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 73% of steel grades. Elongation at break is 22% and the elastic modulus is 217 GPa (31.5 Msi).
Thermal6
M34 is rated for continuous service to 550°C (1,022 °F). It conducts heat at 22 W/m·K (12.7 BTU/hr·ft·°F), worse than 93% of steel grades. Thermal expansion is 10.7 µm/m·K (5.94 µin/in·°F).
Electrical3
M34 conducts electricity at 3.2 % IACS, worse than 87% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (18/100), better than 83% of steel grades.
Sustainability4
Producing a kilogram of M34 takes about 78 MJ of energy and emits 5.6 kg of CO₂ — more than 98% of steel grades. Typical recycled content is 40%.
Manufacturability8
M34's machinability is fair (35/100, worse than 84% of steel grades); weldability poor (15/100); formability not recommended (10/100).
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 steel family
Yield strength against density for every steel grade FabDigit runs. M34 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with M34
Is M34 easy to machine?
Machine only in the annealed condition with sharp carbide or coated-carbide tooling, rigid setups and generous coolant; hardened parts require grinding or EDM with CBN/vitrified alumina wheels.
Can M34 be welded?
Fusion welding is avoided except for tool repair (TIG with matching HSS filler at 500–550 °C preheat plus immediate re-temper); shank-to-flute joints are normally friction- or flash-welded.
Can M34 be formed, bent or molded?
Hot work only, forging 1050–1150 °C finishing above 900 °C followed by slow cooling and full anneal; essentially no cold formability.
M34 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 | 0.85 – 0.92 | 0.89 |
| Mn | 0.15 – 0.4 | 0.3 |
| Si | 0.2 – 0.45 | 0.3 |
| Cr | 3.5 – 4 | 3.75 |
| Mo | 7.75 – 9.2 | 8.3 |
| W | 1.4 – 2.1 | 1.9 |
| V | 1.9 – 2.3 | 2.05 |
| Cored-hardness addition | 7.75 – 8.75 | 8.25 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Fe | balance |
What surface finishes work on M34?
Not anodizable — protect with steam oxide, black oxide, phosphate or oil; nitriding and PVD TiN/TiAlN coatings applied below the tempering temperature give the best tool life.
Surface treatments FabDigit runs on 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).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel M34 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- T11334
How much does M34 cost?
M34 is a high-cost steel ($$$$), pricier than about 78% 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.
M34 — frequently asked
What is M34 used for?
M34 is typically used for cutting tools for tough alloys, milling cutters and drills for high-temp alloys. In short: 550 °C service rating; cobalt toughness balance; for high-temp alloy cutting.
What is the yield strength of M34?
M34 has a typical yield strength of 560 MPa (81.2 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 73% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is M34 easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% of steel grades). Machine only in the annealed condition with sharp carbide or coated-carbide tooling, rigid setups and generous coolant; hardened parts require grinding or EDM with CBN/vitrified alumina wheels.
Can M34 be welded?
Not readily — weldability is rated poor (15/100). Fusion welding is avoided except for tool repair (TIG with matching HSS filler at 500–550 °C preheat plus immediate re-temper); shank-to-flute joints are normally friction- or flash-welded.
What surface finishes work on M34?
Not anodizable — protect with steam oxide, black oxide, phosphate or oil; nitriding and PVD TiN/TiAlN coatings applied below the tempering temperature give the best tool life.
Can M34 be formed, bent or molded?
Hot work only, forging 1050–1150 °C finishing above 900 °C followed by slow cooling and full anneal; essentially no cold formability.
What is the maximum service temperature of M34?
M34 is rated for continuous use to about 550°C (1,022 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between M34-A and M34 HT-67?
A is the default condition — standard supply condition for machining tool blanks before hardening. HT-67: pick for maximum red hardness and wear life on light-feed cutting of high-strength or abrasive materials, at the cost of toughness. Yield strength is 560 MPa in A versus 2,150 MPa in HT-67.
How much does M34 cost?
M34 is a high-cost steel ($$$$), pricier than about 78% 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
- ASTM A600 – Standard Specification for Tool Steel High Speed — ASTM International (2016)
- ASM Handbook Vol. 1: Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 16: Machining — ASM International (1989)
- Cobalt molybdenum high-speed steel product data (M-series) — Böhler / Erasteel (2022)
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.