Steel 835M30 Annealed
Temper
BS 835M30
Choose for rough machining or forming before hardening; note the 4% Ni analysis stays relatively hard even after full annealing.
Values for the Annealed condition
Other 835M30 tempers and conditions
835M30 is listed in 7 conditions; see the grade overview at 835M30.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedThis page Annealed / softened (as-supplied for machining) | Choose for rough machining or forming before hardening; note the 4% Ni analysis stays relatively hard even after full annealing. | 560 | 800 | 18 | 22 HRC | — |
Hardened and tempered, 850–1000 MPa | Lowest H&T strength level; pick when maximum toughness and easiest machining/welding are wanted from this grade. | 730 | 920 | 16 | 27 HRC | — |
Hardened and tempered, 1000–1150 MPa | Common general-engineering H&T level for large-section shafts and couplings. | 890 | 1,075 | 14 | 33 HRC | — |
WDefault Solution heat treated (unstable) | Most widely stocked condition: good balance of ~1150 MPa strength, high toughness and full through-hardening in large sections. | 940 | 1,150 | 14 | 36 HRC | — |
Hardened and tempered, 1150–1300 MPa | Higher-strength aircraft/motorsport level where fatigue capacity matters more than machining ease. | 1,050 | 1,230 | 12 | 39 HRC | — |
Hardened and tempered, 1230–1380 MPa | High-strength landing-gear / torsion-shaft level; grinding usually replaces heavy turning. | 1,130 | 1,300 | 12 | 42 HRC | — |
Hardened and tempered, 1550 MPa minimum | Maximum strength condition for highly stressed aircraft parts; low tempering temperature means reduced toughness and high hydrogen-embrittlement sensitivity. | 1,400 | 1,620 | 9 | 49 HRC | — |
What is 835M30 Annealed?
835M30 Annealed is 835M30 in the Annealed temper — choose for rough machining or forming before hardening; note the 4% Ni analysis stays relatively hard even after full annealing. 835M30 Annealed has a yield strength of 560 MPa (81.2 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 73% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi). 835M30 Annealed has a density of 7.84 g/cm³ (0.283 lb/in³), lighter than 78% of steel grades. It melts at 1,420°C (2,588 °F). W is the default condition FabDigit quotes; Annealed is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- High embodied carbon — 2.9 kg CO₂/kg, worse than 91% of steel grades
- Low electrical conductivity — 5.5 % IACS, worse than 81% of steel grades
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades
835M30 Annealed properties
Typical room-temperature values for 835M30 Annealed; 12 are specific to this condition. Other listed values are 835M30 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
835M30 Annealed has a density of 7.84 g/cm³ (0.283 lb/in³), lighter than 78% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
835M30 Annealed has a yield strength of 560 MPa (81.2 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 73% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
835M30 Annealed is rated for continuous service to 400°C (752 °F). It conducts heat at 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
835M30 Annealed conducts electricity at 5.5 % IACS, worse than 81% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of 835M30 Annealed takes about 36 MJ of energy and emits 2.9 kg of CO₂ — more than 89% of steel grades. Typical recycled content is 30%.
Manufacturability8
835M30 Annealed's machinability is fair (45/100, worse than 65% of steel grades); weldability fair (50/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 835M30 Annealed
Is 835M30 easy to machine?
Machine in the annealed or ≤340 HB H&T condition with rigid setups, sharp carbide and generous coolant; above 400 HB switch to grinding or ceramic/CBN tooling, and allow for the grade's air-hardening tendency in heat-affected surfaces.
Can 835M30 be welded?
Weldable by TIG/MIG/SMAW with low-hydrogen consumables, 150–250 °C preheat maintained through welding and immediate stress relief/temper below the last tempering temperature; re-heat-treat critical joints made in the Y/Z conditions.
Can 835M30 be formed, bent or molded?
Hot forge 1150–850 °C then slow cool or anneal; cold forming is impractical at H&T strengths, so bends and upsets must be done before hardening.
What surface finishes work on 835M30?
Not corrosion resistant — protect with Cd, Zn-Ni or IVD aluminium plating, phosphate or primer/paint; bake at ~190 °C for 8–23 h after electroplating parts above ~1000 MPa to avoid hydrogen embrittlement.
835M30 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 | 0.27 – 0.33 | 0.3 |
| Si | 0.1 – 0.35 | 0.25 |
| Mn | 0.45 – 0.7 | 0.55 |
| Nigives the very high hardenability | 3.9 – 4.3 | 4.1 |
| Cr | 1.1 – 1.4 | 1.25 |
| Mosuppresses temper embrittlement | 0.2 – 0.35 | 0.28 |
| Pmax; aerospace melts typically ≤0.015 | ≤ 0.04 | — |
| Smax; aerospace melts typically ≤0.015 | ≤ 0.04 | — |
| Fe | balance | — |
835M30 Annealed — frequently asked
What is 835M30 Annealed used for?
835M30 Annealed is typically used for aircraft landing gear, structural fittings and high-strength bolts. In short: weldable high-strength aircraft steel; 1150 MPa in default condition; air-hardening, low machinability.
What is the yield strength of 835M30 Annealed?
835M30 Annealed has a typical yield strength of 560 MPa (81.2 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 73% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 835M30 Annealed easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine in the annealed or ≤340 HB H&T condition with rigid setups, sharp carbide and generous coolant; above 400 HB switch to grinding or ceramic/CBN tooling, and allow for the grade's air-hardening tendency in heat-affected surfaces.
Can 835M30 Annealed be welded?
With care — weldability is rated fair (50/100). Weldable by TIG/MIG/SMAW with low-hydrogen consumables, 150–250 °C preheat maintained through welding and immediate stress relief/temper below the last tempering temperature; re-heat-treat critical joints made in the Y/Z conditions.
What surface finishes work on 835M30 Annealed?
Not corrosion resistant — protect with Cd, Zn-Ni or IVD aluminium plating, phosphate or primer/paint; bake at ~190 °C for 8–23 h after electroplating parts above ~1000 MPa to avoid hydrogen embrittlement.
Can 835M30 Annealed be formed, bent or molded?
Hot forge 1150–850 °C then slow cool or anneal; cold forming is impractical at H&T strengths, so bends and upsets must be done before hardening.
What is the maximum service temperature of 835M30 Annealed?
835M30 Annealed 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 835M30-W and 835M30-Z?
W is the default condition — most widely stocked condition: good balance of ~1150 MPa strength, high toughness and full through-hardening in large sections. Z: maximum strength condition for highly stressed aircraft parts; low tempering temperature means reduced toughness and high hydrogen-embrittlement sensitivity. Yield strength is 940 MPa in W versus 1,400 MPa in Z.
Sources
- BS 970-1: Wrought steels for mechanical and allied engineering purposes (835M30 / En30B) — BSI (1991)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- MMPDS-17 (4330V / low-alloy high-strength steels) — Battelle/FAA (2022)
- En30B / 835M30 alloy steel bar datasheet — UK alloy steel stockist (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.