Steel M30-HR (Hot rolled)
Supply condition
AISI/SAE M30 · UNS T11330
Mill-supplied intermediate form; must be spheroidize annealed before machining.
Values for the HR condition
Other M30 tempers and conditions
M30 is listed in 5 conditions; see the grade overview at M30.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hardened & tempered | Choose when interrupted cuts or large tool sections need more toughness than peak hardness. | — | — | — | 62 HRC | 21 W/m·K |
ANNDefault Annealed | Standard as-supplied condition for machining tool blanks before hardening. | 590 | 900 | 15 | 235 HB | 24 W/m·K |
Annealed + ground/turned precision bar | Ready-to-use annealed bar with controlled diameter and surface for tool blank production. | 590 | 900 | 15 | 22 HRC | 2.9 % IACS |
HRThis page Hot rolled | Mill-supplied intermediate form; must be spheroidize annealed before machining. | 800 | 1,080 | 8 | 34 HRC | 2.9 % IACS |
Hardened & tempered | Peak-hardness working condition for high-speed cutting tools where red hardness matters most. | 1,900 | 2,100 | 0.5 | 65 HRC | 21 W/m·K |
What is M30-HR?
M30-HR is M30 supplied in the HR condition — mill-supplied intermediate form; must be spheroidize annealed before machining. M30-HR has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,080 MPa (157 ksi) — stronger than 86% of steel grades. Elongation at break is 8% and the elastic modulus is 217 GPa (31.5 Msi). M30-HR has a density of 8.03 g/cm³ (0.29 lb/in³), heavier than 96% of steel grades. It melts at 1,260°C (2,300 °F). ANN is the default condition FabDigit quotes; HR is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 75/100, better than 94% of steel grades
- High service temperature — 480°C (896 °F), better than 88% of steel grades
- High strength — 800 MPa (116 ksi), better than 86% of steel grades
Limitations
- Difficult to weld — 10/100, worse than 99% of steel grades
- Limited formability — 5/100, worse than 99% of steel grades
- Difficult to machine — 20/100, worse than 97% of steel grades
- Limited ductility — 8%, worse than 95% of steel grades
- High embodied carbon — 3.6 kg CO₂/kg, worse than 94% of steel grades
M30-HR properties
Typical room-temperature values for M30-HR; 22 are specific to this condition. Other listed values are M30 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
M30-HR has a density of 8.03 g/cm³ (0.29 lb/in³), heavier than 96% of steel grades. It melts at 1,260°C (2,300 °F).
Mechanical15
M30-HR has a yield strength of 800 MPa (116 ksi) and a tensile strength of 1,080 MPa (157 ksi) — stronger than 86% of steel grades. Elongation at break is 8% and the elastic modulus is 217 GPa (31.5 Msi).
Thermal6
M30-HR is rated for continuous service to 480°C (896 °F). It conducts heat at 24 W/m·K (13.9 BTU/hr·ft·°F), worse than 90% of steel grades. Thermal expansion is 10.5 µm/m·K (5.83 µin/in·°F).
Electrical3
M30-HR conducts electricity at 2.9 % IACS, worse than 93% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (15/100), better than 75% of steel grades.
Sustainability4
Producing a kilogram of M30-HR takes about 55 MJ of energy and emits 3.6 kg of CO₂ — more than 94% of steel grades. Typical recycled content is 40%.
Manufacturability7
M30-HR's machinability is poor (20/100, worse than 97% of steel grades); weldability not recommended (10/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with M30-HR
Is M30 easy to machine?
Machine only in the annealed condition with rigid setups, sharp carbide or coated-carbide tooling and generous coolant; after hardening only grinding (CBN/SG-alumina wheels) and EDM are practical.
Can M30 be welded?
Essentially not weldable structurally; repair only by TIG/laser with matched HSS filler at 480–540 °C preheat followed by immediate temper, otherwise quench cracking is likely.
Can M30 be formed, bent or molded?
Hot forge 1050–1150 °C, stop above 900 °C and slow-cool in furnace; no meaningful cold forming — heat treat is austenitize 1200–1230 °C (salt/vacuum), quench, then triple temper 540–560 °C 2 h each.
What surface finishes work on M30?
Ferrous and non-stainless: finish with black oxide, steam treatment, nitriding or PVD TiN/TiCN/TiAlN coating; oil or VCI protection required in storage.
M30 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 | 0.75 – 0.85 | 0.8 |
| Mn | 0.15 – 0.4 | 0.28 |
| Si | 0.2 – 0.45 | 0.32 |
| Cr | 3.5 – 4.25 | 4 |
| Mo | 7.75 – 9 | 8.2 |
| W | 1.3 – 2.3 | 2 |
| V | 1 – 1.4 | 1.25 |
| Cored-hardness addition | 4.5 – 5.5 | 5 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
M30-HR — frequently asked
What is M30-HR used for?
M30-HR is typically used for heavy-duty lathe tools, milling cutters for hard materials and high-speed drilling. In short: cobalt red-hardness grade; 480 °C service rating; step up from M2.
What is the yield strength of M30-HR?
M30-HR has a typical yield strength of 800 MPa (116 ksi) and a tensile strength of 1,080 MPa (157 ksi) — stronger than 86% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is M30-HR easy to machine?
Not especially — machinability is rated poor (20/100, worse than 97% of steel grades). Machine only in the annealed condition with rigid setups, sharp carbide or coated-carbide tooling and generous coolant; after hardening only grinding (CBN/SG-alumina wheels) and EDM are practical.
Can M30-HR be welded?
Not readily — weldability is rated not recommended (10/100). Essentially not weldable structurally; repair only by TIG/laser with matched HSS filler at 480–540 °C preheat followed by immediate temper, otherwise quench cracking is likely.
What surface finishes work on M30-HR?
Ferrous and non-stainless: finish with black oxide, steam treatment, nitriding or PVD TiN/TiCN/TiAlN coating; oil or VCI protection required in storage.
Can M30-HR be formed, bent or molded?
Hot forge 1050–1150 °C, stop above 900 °C and slow-cool in furnace; no meaningful cold forming — heat treat is austenitize 1200–1230 °C (salt/vacuum), quench, then triple temper 540–560 °C 2 h each.
What is the maximum service temperature of M30-HR?
M30-HR is rated for continuous use to about 480°C (896 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between M30-ANN and M30 HT-64?
ANN is the default condition — standard as-supplied condition for machining tool blanks before hardening. HT-64: peak-hardness working condition for high-speed cutting tools where red hardness matters most. Yield strength is 590 MPa in ANN versus 1,900 MPa in HT-64.
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 Specialty Handbook: Tool Materials — ASM International (1995)
- ASM Handbook Vol. 16: Machining — ASM International (1989)
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.