Steel En30B Annealed
Temper
Choose for maximum machinability on complex parts that will be carburized or hardened afterwards.
Values for the Annealed condition
Other En30B tempers and conditions
En30B is listed in 11 conditions; see the grade overview at En30B.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedThis page for machining and prior to carburizing | Choose for maximum machinability on complex parts that will be carburized or hardened afterwards. | 550 | 800 | 20 | 235 HB | — |
Normalized (air cooled from austenitizing) and high-temperature tempered | Intermediate stock condition for large forgings; grain refinement before final hardening. | 700 | 950 | 17 | 29 HRC | 5.8 % IACS |
Condition T | Lowest H&T strength class; pick when toughness and machinability matter more than strength. | 730 | 920 | 17 | 28 HRC | — |
Condition U | General-purpose shaft and bolt strength class with good impact toughness. | 800 | 1,000 | 15 | 31 HRC | — |
Condition V | Mid-range class for heavily loaded shafts and gear blanks in large sections. | 880 | 1,075 | 14 | 34 HRC | — |
Cond WDefault Condition W | Most commonly stocked H&T class — best balance of high strength and useful toughness in large diameters. | 980 | 1,150 | 13 | 37 HRC | — |
Nitrided after hardening and tempering | Use when a thin, distortion-free hard skin is needed on finish-machined H&T parts. | 1,000 | 1,150 | 11 | 61 HRC | 5.5 % IACS |
Carburized, hardened and low-temperature tempered (case-hardened) | Pick for gears, cams and splines needing a 60+ HRC wear surface over a 1100–1250 MPa tough core. | 1,020 | 1,200 | 11 | 61 HRC | — |
Condition X | High-strength class for aerospace bolts, links and torsion members; machine before hardening where possible. | 1,050 | 1,225 | 12 | 40 HRC | — |
Condition Y | Very high strength class; check notch sensitivity and hydrogen embrittlement risk when plating. | 1,120 | 1,300 | 11 | 42 HRC | — |
Condition Z | Maximum strength class (aircraft-quality bolts, high-stress links); low ductility and toughness, grind rather than machine. | 1,400 | 1,620 | 8 | 49 HRC | — |
What is En30B Annealed?
En30B Annealed is En30B in the Annealed temper — choose for maximum machinability on complex parts that will be carburized or hardened afterwards. En30B Annealed has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 71% of steel grades. Elongation at break is 20% and the elastic modulus is 207 GPa (30 Msi). En30B Annealed has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). Cond W is the default condition FabDigit quotes; Annealed is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
Limitations
- Difficult to weld — 20/100, worse than 84% of steel grades
- High embodied carbon — 2.5 kg CO₂/kg, worse than 82% of steel grades
- Low electrical conductivity — 5.5 % IACS, worse than 81% of steel grades
- Poor heat conductor — 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades
- Difficult to machine — 40/100, worse than 77% of steel grades
En30B Annealed properties
Typical room-temperature values for En30B Annealed; 11 are specific to this condition. Other listed values are En30B reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
En30B Annealed has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
En30B Annealed has a yield strength of 550 MPa (79.8 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 71% of steel grades. Elongation at break is 20% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
En30B Annealed is rated for continuous service to 350°C (662 °F). It conducts heat at 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
En30B Annealed conducts electricity at 5.5 % IACS, worse than 81% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of En30B Annealed takes about 36 MJ of energy and emits 2.5 kg of CO₂ — more than 89% of steel grades. Typical recycled content is 35%.
Manufacturability6
En30B Annealed's machinability is fair (40/100, worse than 77% of steel grades); weldability poor (20/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with En30B Annealed
Is En30B easy to machine?
Rough machine annealed (~235 HB) and finish after hardening by grinding; in condition W/X use rigid setups, sharp carbide or coated inserts, low speed with generous coolant, and stress-relieve before finishing.
Can En30B be welded?
Poor weldability — air-hardening 4% Ni-Cr-Mo steel; if unavoidable, preheat 250–350 °C, use low-hydrogen or matching consumables, and temper immediately after welding to avoid HAZ cracking.
Can En30B be formed, bent or molded?
Hot forge 1050–1150 °C with slow cooling and full anneal; cold forming is impractical above the annealed condition.
What surface finishes work on En30B?
Takes hard chrome, zinc, cadmium and phosphate coatings well — bake at 190–210 °C after plating to relieve hydrogen; polishes and grinds cleanly for gear and bearing surfaces.
En30B 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 |
|---|---|---|
| C835M30 / En30B carbon range | 0.26 – 0.34 | 0.3 |
| Si | 0.1 – 0.35 | 0.25 |
| Mn | 0.4 – 0.7 | 0.55 |
| Nigives deep hardenability and low-temperature toughness | 3.9 – 4.3 | 4.1 |
| Cr | 1.1 – 1.4 | 1.25 |
| Mosuppresses temper embrittlement | 0.15 – 0.3 | 0.25 |
| Pmax; aircraft quality often 0.025 max | ≤ 0.04 | — |
| Smax; aircraft quality often 0.025 max | ≤ 0.04 | — |
| Fe | balance | — |
En30B Annealed — frequently asked
What is En30B Annealed used for?
En30B Annealed is typically used for gears, pins, cams and high-load bearings. In short: highest core strength carburizing steel; 9310-equivalent gear steel; hard case, tough core.
What is the yield strength of En30B Annealed?
En30B Annealed has a typical yield strength of 550 MPa (79.8 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 71% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is En30B Annealed easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Rough machine annealed (~235 HB) and finish after hardening by grinding; in condition W/X use rigid setups, sharp carbide or coated inserts, low speed with generous coolant, and stress-relieve before finishing.
Can En30B Annealed be welded?
Not readily — weldability is rated poor (20/100). Poor weldability — air-hardening 4% Ni-Cr-Mo steel; if unavoidable, preheat 250–350 °C, use low-hydrogen or matching consumables, and temper immediately after welding to avoid HAZ cracking.
What surface finishes work on En30B Annealed?
Takes hard chrome, zinc, cadmium and phosphate coatings well — bake at 190–210 °C after plating to relieve hydrogen; polishes and grinds cleanly for gear and bearing surfaces.
Can En30B Annealed be formed, bent or molded?
Hot forge 1050–1150 °C with slow cooling and full anneal; cold forming is impractical above the annealed condition.
What is the maximum service temperature of En30B Annealed?
En30B Annealed is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- BS 970-1: Wrought steels for mechanical and allied engineering purposes — 835M30 (En30B) — BSI (1983)
- BS 970-3 / BS S.106 aircraft-quality 4% Ni-Cr-Mo steel requirements — BSI (1991)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4: Heat Treating (carburizing and hardenability of Ni-Cr-Mo steels) — ASM International (1991)
- Machinery's Handbook (machinability ratings, alloy steels) — Industrial Press (2020)
- En30B (835M30) alloy steel bar datasheet — UK specialty steel stockists (e.g. West Yorkshire Steel / Smiths Metal Centres) (2023)
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.