Steel M45 H&T+Cryo
Heat-treated state
AISI/SAE M45
H&T+Cryo = h&T + Deep Cryogenic Treatment
Choose when dimensional stability and retained-austenite removal matter (precision gauges, long broaches, fine-pitch taps).
Values for the H&T+Cryo condition
Other M45 tempers and conditions
M45 is listed in 4 conditions; see the grade overview at M45.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
peak hardness 67–69 HRC (1190–1210 °C, 3×540–550 °C) | Maximum wear resistance and red hardness for drills, end mills and form tools cutting hard/heat-resistant alloys. | — | — | 0 | 68 HRC | — |
AnnealedDefault spheroidize annealed bar/blank stock | Standard supply condition for bar, blanks and preforms; soft enough to turn, mill and drill before hardening. | 620 | 950 | 12 | 26 HRC | — |
H&T + Plasma/Salt-bath Nitrided surface | Low-temperature surface treatment for extra abrasion and galling resistance on taps, hobs and gear cutters; case is brittle so use thin layers. | 2,000 | 2,250 | 0.5 | 68 HRC | 3 % IACS |
H&T+CryoThis page H&T + Deep Cryogenic Treatment | Choose when dimensional stability and retained-austenite removal matter (precision gauges, long broaches, fine-pitch taps). | 2,050 | 2,300 | 0.5 | 69 HRC | 3 % IACS |
What is M45 H&T+Cryo?
M45 H&T+Cryo is M45 heat treated to H&T+Cryo — choose when dimensional stability and retained-austenite removal matter (precision gauges, long broaches, fine-pitch taps). M45 H&T+Cryo has a yield strength of 2,050 MPa (297 ksi) and a tensile strength of 2,300 MPa (334 ksi) — stronger than 100% of steel grades. Elongation at break is 0.5% and the elastic modulus is 228 GPa (33.1 Msi). M45 H&T+Cryo has a density of 8.1 g/cm³ (0.293 lb/in³), heavier than 97% of steel grades. It melts at 1,260°C (2,300 °F). Annealed is the default condition FabDigit quotes; H&T+Cryo is available on request or by drawing note.
Advantages
- High strength — 2,050 MPa (297 ksi), better than 100% of steel grades
- High service temperature — 620°C (1,148 °F), better than 99% of steel grades
- Polishes to a fine finish — 75/100, better than 94% of steel grades
Limitations
- Limited ductility — 0.5%, worse than 100% of steel grades
- Low fracture toughness — 13 MPa·√m (11.8 ksi·√in), worse than 100% of steel grades
- Difficult to machine — 4/100, worse than 100% of steel grades
- Difficult to weld — 5/100, worse than 100% of steel grades
- Limited formability — 1/100, worse than 100% of steel grades
M45 H&T+Cryo properties
Typical room-temperature values for M45 H&T+Cryo; 21 are specific to this condition. Other listed values are M45 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
M45 H&T+Cryo has a density of 8.1 g/cm³ (0.293 lb/in³), heavier than 97% of steel grades. It melts at 1,260°C (2,300 °F).
Mechanical16
M45 H&T+Cryo has a yield strength of 2,050 MPa (297 ksi) and a tensile strength of 2,300 MPa (334 ksi) — stronger than 100% of steel grades. Elongation at break is 0.5% and the elastic modulus is 228 GPa (33.1 Msi).
Thermal6
M45 H&T+Cryo is rated for continuous service to 620°C (1,148 °F). It conducts heat at 20 W/m·K (11.6 BTU/hr·ft·°F), worse than 96% of steel grades. Thermal expansion is 10.8 µm/m·K (6 µin/in·°F).
Electrical3
M45 H&T+Cryo conducts electricity at 3 % IACS, worse than 91% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (19/100), better than 86% of steel grades.
Sustainability4
Producing a kilogram of M45 H&T+Cryo takes about 55 MJ of energy and emits 4.2 kg of CO₂ — more than 94% of steel grades. Typical recycled content is 35%.
Manufacturability7
M45 H&T+Cryo's machinability is not recommended (4/100, worse than 100% of steel grades); weldability not recommended (5/100); formability not recommended (1/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with M45 H&T+Cryo
Is M45 easy to machine?
Machine only in the annealed condition with rigid setups, cobalt or carbide tooling and flood coolant; after hardening the part can only be ground (soft SG/CBN wheels, light infeed to avoid grinding burn) or EDM'd.
Can M45 be welded?
Not a structural weld metal — repair only by TIG/laser with matching HSS filler at 500–550 °C preheat followed immediately by a full triple temper; expect microcracking otherwise.
Can M45 be formed, bent or molded?
Hot work 1050–900 °C with slow furnace cooling to the spheroidized state; cold forming is not practical, and blanks must be finished by machining or grinding.
What surface finishes work on M45?
Black oxide, steam-oxide or nitride for anti-galling; TiN/TiCN/TiAlN PVD at ≤500 °C is standard for cutting tools; unprotected surfaces must be oiled since the 4 % Cr gives no real corrosion resistance.
M45 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 to form MC/M6C carbides | 1.25 – 1.4 | 1.3 |
| W | 8 – 9 | 8.5 |
| Mo | 4.75 – 5.5 | 5.1 |
| Cr | 3.75 – 4.5 | 4.1 |
| V | 1.6 – 2.05 | 1.8 |
| Coraises hot hardness / red hardness | 5 – 5.5 | 5.2 |
| Mn | 0.15 – 0.4 | 0.28 |
| Si | 0.15 – 0.65 | 0.35 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Febalance; composition per ASM high-speed-steel tables — verify against mill certificate, M45 is a low-volume super-HSS grade | balance | — |
M45 H&T+Cryo — frequently asked
What is M45 H&T+Cryo used for?
M45 H&T+Cryo is typically used for motor stator and rotor laminations, distribution transformer cores, small generator cores, solenoid and relay cores, reactor and ballast laminations and pole pieces and magnetic shunts. In short: non-oriented electrical coil.
What is the yield strength of M45 H&T+Cryo?
M45 H&T+Cryo has a typical yield strength of 2,050 MPa (297 ksi) and a tensile strength of 2,300 MPa (334 ksi) — stronger than 100% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is M45 H&T+Cryo easy to machine?
Not especially — machinability is rated not recommended (4/100, worse than 100% of steel grades). Machine only in the annealed condition with rigid setups, cobalt or carbide tooling and flood coolant; after hardening the part can only be ground (soft SG/CBN wheels, light infeed to avoid grinding burn) or EDM'd.
Can M45 H&T+Cryo be welded?
Not readily — weldability is rated not recommended (5/100). Not a structural weld metal — repair only by TIG/laser with matching HSS filler at 500–550 °C preheat followed immediately by a full triple temper; expect microcracking otherwise.
What surface finishes work on M45 H&T+Cryo?
Black oxide, steam-oxide or nitride for anti-galling; TiN/TiCN/TiAlN PVD at ≤500 °C is standard for cutting tools; unprotected surfaces must be oiled since the 4 % Cr gives no real corrosion resistance.
Can M45 H&T+Cryo be formed, bent or molded?
Hot work 1050–900 °C with slow furnace cooling to the spheroidized state; cold forming is not practical, and blanks must be finished by machining or grinding.
What is the maximum service temperature of M45 H&T+Cryo?
M45 H&T+Cryo is rated for continuous use to about 620°C (1,148 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in M45 H&T+Cryo?
Yes — M45 H&T+Cryo is available for sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys (tool steel chapter) — ASM International (1990)
- Tool Steels, 5th ed. (Roberts, Krauss, Kennedy) — ASM International (1998)
- ASTM A600 — Tool Steel High Speed Tool Steels — ASTM (2016)
- Cobalt super-HSS grade datasheets (M42/M35 class) — Böhler / Erasteel (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.