Steel 34CrAlNi7-10
EN 34CrAlNi7-10 · also Nitralloy 135
34CrAlNi7-10 (1.8550, also traded as Nitralloy 135) is a nickel-modified chromium-aluminium nitriding steel from the European nitriding-steel family, where about 1 % aluminium produces the hard nitrided case and nickel raises core toughness.
Reference datasheet — 34CrAlNi7-10 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 +QT condition
34CrAlNi7-10 tempers and conditions
34CrAlNi7-10 is supplied in 8 conditions, soft to hard. +QT is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Delivery condition for bar/forging stock that will be rough machined and then quenched, tempered and nitrided in-house. | 450 | 720 | 18 | 225 HB | — |
Cold drawn | Precision bar stock with close tolerance and clean surface for small nitrided pins, spindles and valve stems. | 600 | 800 | 11 | 24 HRC | 6.6 % IACS |
Normalized | Grain-refining condition after forging; rarely a final supply state because the alloy air-hardens to a fairly hard bainitic/martensitic structure. | 620 | 950 | 12 | 31 HRC | 6.6 % IACS |
+QT | Very large forged rolls, screws and cylinders where only the reduced strength class can be guaranteed at core. | 620 | 850 | 15 | 26 HRC | 6.6 % IACS |
+QT | Heavy-section bar and forgings where mass effect lowers the guaranteed core strength. | 680 | 900 | 14 | 29 HRC | 6.6 % IACS |
+QT + nitrocarburized | Short-cycle ferritic nitrocarburizing for anti-scuffing/anti-galling surfaces where a thin, tough compound layer is enough. | 720 | 950 | 12 | 63 HRC | 6.6 % IACS |
+QTDefault Quenched and tempered | Standard stock condition: oil/water quenched and high-temperature tempered core, ready for finish machining and gas nitriding. | 780 | 1,000 | 13 | 33 HRC | — |
+QT + gas nitrided | Final functional condition: Q&T core plus 500–530 °C gas nitriding for maximum surface hardness, wear and bending-fatigue strength. | 780 | 1,000 | 11 | 68 HRC | — |
What is 34CrAlNi7-10?
34CrAlNi7-10 (1.8550, also traded as Nitralloy 135) is a nickel-modified chromium-aluminium nitriding steel from the European nitriding-steel family, where about 1 % aluminium produces the hard nitrided case and nickel raises core toughness. It is chosen for nitrided parts that see shock loading in heavier sections and is supplied as Q&T bar and forgings at roughly 780 MPa yield, 1000 MPa tensile, 13 % elongation and 310 HB (33 HRC), with service to 500 °C. It should be treated as non-weldable and has no corrosion resistance without a coating. 41CrAlMo7-10 is the lower-cost alternative where impact loading is moderate. 34CrAlNi7-10 has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,400°C (2,552 °F). 34CrAlNi7-10 has a yield strength of 780 MPa (113 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 86% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi).
What is 34CrAlNi7-10 used for?
- gears
- crankshafts
- high-load pins and bushings
Advantages
- High service temperature — 500°C (932 °F), better than 90% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- High strength — 780 MPa (113 ksi), better than 86% of steel grades
Limitations
- Difficult to weld — 12/100, worse than 96% of steel grades
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades
- Limited formability — 20/100, worse than 80% of steel grades
- Limited ductility — 13%, worse than 78% of steel grades
- Low electrical conductivity — 6.6 % IACS, worse than 76% of steel grades
34CrAlNi7-10 properties
Typical room-temperature values for 34CrAlNi7-10-+QT; bars are the position among steel grades.
Physical3
34CrAlNi7-10 has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
34CrAlNi7-10 has a yield strength of 780 MPa (113 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 86% of steel grades. Elongation at break is 13% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
34CrAlNi7-10 is rated for continuous service to 500°C (932 °F). It conducts heat at 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades. Thermal expansion is 11.6 µm/m·K (6.44 µin/in·°F).
Electrical3
34CrAlNi7-10 conducts electricity at 6.6 % IACS, worse than 76% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of 34CrAlNi7-10 takes about 31 MJ of energy and emits 2.2 kg of CO₂ — more than 64% of steel grades. Typical recycled content is 25%.
Manufacturability7
34CrAlNi7-10's machinability is fair (45/100, worse than 65% of steel grades); weldability not recommended (12/100); formability poor (20/100).
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. 34CrAlNi7-10 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 34CrAlNi7-10
Is 34CrAlNi7-10 easy to machine?
Finish machine in the +QT condition with rigid setups and coated carbide (~90–140 m/min); leave 0.05–0.1 mm grinding stock since the nitrided case is essentially unmachinable except by grinding/lapping.
Can 34CrAlNi7-10 be welded?
Regard as non-weldable — high Al and high hardenability cause cracking and destroy the nitriding response; if unavoidable, use matching filler with 300–350 °C preheat plus full re-Q&T.
Can 34CrAlNi7-10 be formed, bent or molded?
Hot forge 1100→850 °C with slow cooling and mandatory soft anneal; cold forming limited to light straightening of annealed bar.
34CrAlNi7-10 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 | 0.3 – 0.37 | 0.34 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.4 – 0.7 | 0.55 |
| P | ≤ 0.03 | |
| Smax; low-S variants for cleanliness | ≤ 0.04 | |
| Cr | 1.5 – 1.8 | 1.65 |
| Mo | 0.15 – 0.25 | 0.2 |
| Niadded for core toughness/hardenability | 0.85 – 1.15 | 1 |
| Alforms hard AlN in nitrided case | 0.8 – 1.2 | 1 |
| Fe | balance |
What surface finishes work on 34CrAlNi7-10?
Stress relieve at ~600–650 °C after rough machining, then gas nitride 500–530 °C for 0.3–0.6 mm case (≥900 HV); finish by grinding/superfinishing, and use oil, phosphate or black-oxide for corrosion protection (no anodizing).
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 34CrAlNi7-10 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.855034CrAlNi7
- Trade names
- Nitralloy 135
How much does 34CrAlNi7-10 cost?
34CrAlNi7-10 is a standard-cost steel ($$), cheaper than about 71% 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.
34CrAlNi7-10 — frequently asked
What is 34CrAlNi7-10 used for?
34CrAlNi7-10 is typically used for gears, crankshafts and high-load pins and bushings. In short: nickel-toughened nitriding steel; best for shock-loaded parts; 500 °C service capability.
What is the yield strength of 34CrAlNi7-10?
34CrAlNi7-10 has a typical yield strength of 780 MPa (113 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 86% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 34CrAlNi7-10 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Finish machine in the +QT condition with rigid setups and coated carbide (~90–140 m/min); leave 0.05–0.1 mm grinding stock since the nitrided case is essentially unmachinable except by grinding/lapping.
Can 34CrAlNi7-10 be welded?
Not readily — weldability is rated not recommended (12/100). Regard as non-weldable — high Al and high hardenability cause cracking and destroy the nitriding response; if unavoidable, use matching filler with 300–350 °C preheat plus full re-Q&T.
What surface finishes work on 34CrAlNi7-10?
Stress relieve at ~600–650 °C after rough machining, then gas nitride 500–530 °C for 0.3–0.6 mm case (≥900 HV); finish by grinding/superfinishing, and use oil, phosphate or black-oxide for corrosion protection (no anodizing).
Can 34CrAlNi7-10 be formed, bent or molded?
Hot forge 1100→850 °C with slow cooling and mandatory soft anneal; cold forming limited to light straightening of annealed bar.
What is the maximum service temperature of 34CrAlNi7-10?
34CrAlNi7-10 is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 34CrAlNi7-10 cost?
34CrAlNi7-10 is a standard-cost steel ($$), cheaper than about 71% 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
- EN 10085 — Nitriding steels: technical delivery conditions — CEN (2001)
- DIN 17211 (superseded) — Nitriding steels — DIN (1987)
- ASM Handbook Vol. 4A — Steel Heat Treating Fundamentals and Processes (Nitriding) — ASM International (2013)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Nitriding steel bar datasheets (1.8550 / 1.8519 family) — Böhler / Ovako / Lucchini (2022)
- GB/T 3077 — Alloy structural steels (38CrMoAl comparison grade) — SAC (2015)
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.