Steel 26NiCrMo14-6 +TH
Hardness band
EN 26NiCrMo14-6
+TH = treated to a specified hardness range
Pick when the mill must guarantee a machining hardness band for automatic/CNC production lines.
Values for the +TH condition
Other 26NiCrMo14-6 tempers and conditions
26NiCrMo14-6 is listed in 9 conditions; see the grade overview at 26NiCrMo14-6.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+ADefault Annealed | Standard stock condition for bar and forgings that will be machined and then carburized or through-hardened. | 460 | 780 | 17 | 220 HB | — |
Treated for shearability | Choose for bar that must be cold sheared or cropped to blanks before forging/machining. | 480 | 800 | 16 | 21 HRC | 5.7 % IACS |
+THThis page Treated to a specified hardness range | Pick when the mill must guarantee a machining hardness band for automatic/CNC production lines. | 560 | 880 | 15 | 23 HRC | 5.7 % IACS |
Cold drawn | Small-diameter bar with close tolerance and bright finish for parts machined before case hardening. | 720 | 880 | 10 | 26 HRC | 5.7 % IACS |
Normalized | Grain-refining step after forging; note that this air-hardening grade comes out hard and normally needs a subsequent temper or anneal before machining. | 750 | 1,080 | 12 | 34 HRC | 5.7 % IACS |
+QT 30–34 HRC | Through-hardened condition for heavy shafts and machined-after-heat-treat parts needing high toughness. | 900 | 1,050 | 14 | 32 HRC | — |
Blank hardened | Reference condition of EN 10084 that documents the core strength this grade develops in a carburized part. | 980 | 1,300 | 10 | 40 HRC | — |
Carburized and hardened | Final service condition for heavy gears and pinions: hard wear-resistant case over a tough, deeply hardened high-nickel core. | 980 | 1,300 | 9 | 60 HRC | 5.5 % IACS |
+QT 38–42 HRC | Highest practical through-hardened strength level for shafts and fasteners where toughness must still be retained. | 1,150 | 1,300 | 11 | 40 HRC | — |
What is 26NiCrMo14-6 +TH?
26NiCrMo14-6 +TH is 26NiCrMo14-6 heat treated to +TH — pick when the mill must guarantee a machining hardness band for automatic/CNC production lines. 26NiCrMo14-6 +TH has a yield strength of 560 MPa (81.2 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 73% of steel grades. Elongation at break is 15% and the elastic modulus is 207 GPa (30 Msi). 26NiCrMo14-6 +TH has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,430°C (2,606 °F). +A is the default condition FabDigit quotes; +TH is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 70/100, better than 87% of steel grades
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
Limitations
- Low electrical conductivity — 5.7 % IACS, worse than 80% of steel grades
- Poor heat conductor — 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades
- Difficult to weld — 25/100, worse than 77% of steel grades
26NiCrMo14-6 +TH properties
Typical room-temperature values for 26NiCrMo14-6 +TH; 23 are specific to this condition. Other listed values are 26NiCrMo14-6 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
26NiCrMo14-6 +TH has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,430°C (2,606 °F).
Mechanical15
26NiCrMo14-6 +TH has a yield strength of 560 MPa (81.2 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 73% of steel grades. Elongation at break is 15% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
26NiCrMo14-6 +TH is rated for continuous service to 400°C (752 °F). It conducts heat at 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical3
26NiCrMo14-6 +TH conducts electricity at 5.7 % IACS, worse than 80% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of 26NiCrMo14-6 +TH takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 30%.
Manufacturability8
26NiCrMo14-6 +TH's machinability is fair (42/100, worse than 73% of steel grades); weldability poor (25/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 26NiCrMo14-6 +TH
Is 26NiCrMo14-6 easy to machine?
Machine in the soft-annealed (≤248 HB) condition with rigid setups, sharp coated carbide and generous coolant; the tough high-Ni matrix work-hardens and gives stringy chips, so use positive rakes and moderate speeds (~48 % of AISI 1212).
Can 26NiCrMo14-6 be welded?
Poor weldability — CE ≈ 0.9; if unavoidable, use low-hydrogen consumables, 250–350 °C preheat/interpass and immediate post-weld temper below the last tempering temperature, then re-heat-treat where possible.
Can 26NiCrMo14-6 be formed, bent or molded?
Hot forge at 1100–850 °C with slow controlled cooling (air-hardening grade), then anneal; cold forming is limited to light straightening because of the high strength and hardenability.
What surface finishes work on 26NiCrMo14-6?
No natural corrosion resistance: use black oxide, manganese phosphate, zinc/zinc-nickel plating or paint; bake plated high-strength parts at 190–210 °C to relieve hydrogen, and grind/shot-peen carburized surfaces for maximum fatigue life.
26NiCrMo14-6 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 | 0.22 – 0.29 | 0.26 |
| Si | ≤ 0.4 | 0.25 |
| Mn | 0.3 – 0.6 | 0.45 |
| P | ≤ 0.03 | 0.01 |
| Smax; lower S grades supplied for aerospace | ≤ 0.04 | 0.02 |
| Cr | 1.2 – 1.5 | 1.35 |
| Mo | 0.25 – 0.35 | 0.3 |
| Ni | 3.2 – 3.6 | 3.4 |
| Fe | balance | — |
26NiCrMo14-6 +TH — frequently asked
What is 26NiCrMo14-6 +TH used for?
26NiCrMo14-6 +TH is typically used for large gears, aircraft landing gear parts, heavy-duty shafts, high-strength bolts and carburized transmission components. In short: deepest-hardening EN alloy steel; high toughness in heavy sections; aerospace-grade 4340 equivalent.
What is the yield strength of 26NiCrMo14-6 +TH?
26NiCrMo14-6 +TH has a typical yield strength of 560 MPa (81.2 ksi) and a tensile strength of 880 MPa (128 ksi) — stronger than 73% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 26NiCrMo14-6 +TH easy to machine?
Not especially — machinability is rated fair (42/100, worse than 73% of steel grades). Machine in the soft-annealed (≤248 HB) condition with rigid setups, sharp coated carbide and generous coolant; the tough high-Ni matrix work-hardens and gives stringy chips, so use positive rakes and moderate speeds (~48 % of AISI 1212).
Can 26NiCrMo14-6 +TH be welded?
Not readily — weldability is rated poor (25/100). Poor weldability — CE ≈ 0.9; if unavoidable, use low-hydrogen consumables, 250–350 °C preheat/interpass and immediate post-weld temper below the last tempering temperature, then re-heat-treat where possible.
What surface finishes work on 26NiCrMo14-6 +TH?
No natural corrosion resistance: use black oxide, manganese phosphate, zinc/zinc-nickel plating or paint; bake plated high-strength parts at 190–210 °C to relieve hydrogen, and grind/shot-peen carburized surfaces for maximum fatigue life.
Can 26NiCrMo14-6 +TH be formed, bent or molded?
Hot forge at 1100–850 °C with slow controlled cooling (air-hardening grade), then anneal; cold forming is limited to light straightening because of the high strength and hardenability.
What is the maximum service temperature of 26NiCrMo14-6 +TH?
26NiCrMo14-6 +TH 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 26NiCrMo14-6 +A and 26NiCrMo14-6 QT-40?
+A is the default condition — standard stock condition for bar and forgings that will be machined and then carburized or through-hardened. QT-40: highest practical through-hardened strength level for shafts and fasteners where toughness must still be retained. Yield strength is 460 MPa in +A versus 1,150 MPa in QT-40.
Sources
- EN 10084 — Case hardening steels: technical delivery conditions — CEN (2008)
- EN 10250-3 — Open die steel forgings: alloy special steels — CEN (1999)
- EN 10083-3 — Steels for quenching and tempering: alloy steels — CEN (2006)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (carburizing of Ni-Cr-Mo steels) — ASM International (1991)
- Case-hardening steel 1.6958 / 26NiCrMo14-6 mill datasheet — European special steel producer (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.