Steel G25NiCrMo6 +QT1
Heat-treated state · default condition
EN 1.6554
+QT1 = quenched and tempered, lower strength class
Standard supply condition: best strength/toughness balance for heavy structural and machinery castings, easier to machine and weld-repair than +QT2.
Values for the +QT1 condition
Other G25NiCrMo6 tempers and conditions
G25NiCrMo6 is listed in 4 conditions; see the grade overview at G25NiCrMo6.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Used for rough machining, extensive weld fabrication or repair before final quench and temper. | 400 | 640 | 18 | 11 HRC | 7.6 % IACS |
Normalized | Interim / lower-cost condition for lightly loaded or thick castings that will be machined and later hardened; strength well below +QT levels. | 480 | 720 | 15 | 18 HRC | 7.4 % IACS |
+QT1DefaultThis page Quenched and tempered, lower strength class | Standard supply condition: best strength/toughness balance for heavy structural and machinery castings, easier to machine and weld-repair than +QT2. | 640 | 860 | 13 | 25 HRC | — |
Quenched and tempered, higher strength class | Choose when higher yield strength is needed for weight-critical highly loaded castings; accept lower ductility, toughness and machinability. | 750 | 960 | 10 | 30 HRC | — |
What is G25NiCrMo6 +QT1?
G25NiCrMo6 +QT1 is G25NiCrMo6 heat treated to +QT1 — standard supply condition: best strength/toughness balance for heavy structural and machinery castings, easier to machine and weld-repair than +QT2. G25NiCrMo6 +QT1 has a yield strength of 640 MPa (92.8 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 79% of steel grades. Elongation at break is 13% and the elastic modulus is 208 GPa (30.2 Msi). G25NiCrMo6 +QT1 has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,420°C (2,588 °F).
Advantages
- High strength — 640 MPa (92.8 ksi), better than 79% of steel grades
Limitations
- Limited formability — 10/100, worse than 95% of steel grades
- Limited ductility — 13%, worse than 78% of steel grades
G25NiCrMo6 +QT1 properties
Typical room-temperature values for G25NiCrMo6 +QT1; 15 are specific to this condition. Other listed values are G25NiCrMo6 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
G25NiCrMo6 +QT1 has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
G25NiCrMo6 +QT1 has a yield strength of 640 MPa (92.8 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 79% of steel grades. Elongation at break is 13% and the elastic modulus is 208 GPa (30.2 Msi).
Thermal6
G25NiCrMo6 +QT1 is rated for continuous service to 400°C (752 °F). It conducts heat at 38 W/m·K (22 BTU/hr·ft·°F), worse than 69% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
G25NiCrMo6 +QT1 conducts electricity at 7.2 % IACS, worse than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of G25NiCrMo6 +QT1 takes about 27 MJ of energy and emits 2.1 kg of CO₂ — less than 59% of steel grades. Typical recycled content is 80%.
Manufacturability8
G25NiCrMo6 +QT1's machinability is fair (45/100, worse than 65% of steel grades); weldability fair (40/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with G25NiCrMo6 +QT1
Is G25NiCrMo6 easy to machine?
Machine in +A/+N condition where possible; in +QT use rigid setups, carbide inserts at 60–120 m/min with positive feed and copious coolant, expect abrasive casting skin on first cut.
Can G25NiCrMo6 be welded?
Weldable with low-hydrogen matched Ni-Cr-Mo consumables; preheat 200–300 °C depending on section, maintain interpass temperature and apply post-weld tempering 30–50 °C below the last tempering temperature.
Can G25NiCrMo6 be formed, bent or molded?
Sand or no-bake moulded with generous risers and chills; keep section transitions gradual, allow ~2 % solidification shrinkage and normalize/homogenize before quench and temper.
What surface finishes work on G25NiCrMo6?
Shot-blast to SA 2½, then epoxy/zinc-rich primer, hot-dip galvanizing or metallizing; can be nitrided or induction hardened locally for wear faces, chrome/nickel plating requires hydrogen bake-out.
G25NiCrMo6 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 |
|---|---|---|
| Clow enough for weld repair with preheat | 0.2 – 0.3 | 0.25 |
| Si | ≤ 0.6 | 0.4 |
| Mn | 0.5 – 0.9 | 0.7 |
| P | ≤ 0.02 | 0.01 |
| S | ≤ 0.02 | 0.01 |
| Cr | 0.4 – 0.9 | 0.65 |
| Nimain difference vs G25NiCrMo3 | 1.2 – 1.8 | 1.5 |
| Mohardenability, temper embrittlement resistance | 0.2 – 0.4 | 0.3 |
| Vresidual | ≤ 0.08 | — |
| Fe | balance | — |
G25NiCrMo6 +QT1 — frequently asked
What is G25NiCrMo6 +QT1 used for?
G25NiCrMo6 +QT1 is typically used for heavy machinery castings, crankcases and large structural components subject to shock loading. In short: tougher than G25NiCrMo3; shock-load cast steel; weldable with preheat.
What is the yield strength of G25NiCrMo6 +QT1?
G25NiCrMo6 +QT1 has a typical yield strength of 640 MPa (92.8 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 79% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is G25NiCrMo6 +QT1 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine in +A/+N condition where possible; in +QT use rigid setups, carbide inserts at 60–120 m/min with positive feed and copious coolant, expect abrasive casting skin on first cut.
Can G25NiCrMo6 +QT1 be welded?
With care — weldability is rated fair (40/100). Weldable with low-hydrogen matched Ni-Cr-Mo consumables; preheat 200–300 °C depending on section, maintain interpass temperature and apply post-weld tempering 30–50 °C below the last tempering temperature.
What surface finishes work on G25NiCrMo6 +QT1?
Shot-blast to SA 2½, then epoxy/zinc-rich primer, hot-dip galvanizing or metallizing; can be nitrided or induction hardened locally for wear faces, chrome/nickel plating requires hydrogen bake-out.
Can G25NiCrMo6 +QT1 be formed, bent or molded?
Sand or no-bake moulded with generous risers and chills; keep section transitions gradual, allow ~2 % solidification shrinkage and normalize/homogenize before quench and temper.
What is the maximum service temperature of G25NiCrMo6 +QT1?
G25NiCrMo6 +QT1 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.
Sources
- EN 10293 — Steel castings for general engineering uses — CEN (2015)
- EN 10340 — Steel castings for structural uses — CEN (2007)
- EN 10027-2 — Numerical designation system for steels (material number 1.6554) — CEN (2015)
- ASM Handbook Vol.1: Properties and Selection — Cast Low-Alloy Steels — ASM International (1990)
- ASM Handbook Vol.15: Casting — ASM International (2008)
- Steel Castings Handbook — Steel Founders' Society of America / ASM (1995)
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.