Steel G24Mn6 +QT3
Heat-treated state
EN 1.1118
+QT3 = quenched and tempered, high strength class
Highest-strength Q&T class, for thinner, well-hardenable sections where yield strength and wear dominate over toughness.
Values for the +QT3 condition
Other G24Mn6 tempers and conditions
G24Mn6 is listed in 5 conditions; see the grade overview at G24Mn6.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest condition, used to ease heavy rough machining or stress-relieve complex castings before final heat treatment. | 300 | 520 | 23 | 150 HB | 9.5 % IACS |
Normalized | Economical condition for less critical castings or as an intermediate state before machining and final Q&T. | 340 | 580 | 20 | 170 HB | — |
+QT1Default Quenched and tempered, lower strength / highest toughness class | Default supply condition: best combination of −40 °C impact toughness and weldability for thicker structural castings. | 440 | 660 | 18 | 195 HB | — |
Quenched and tempered, intermediate strength class | Pick when higher yield strength is needed for load-bearing machine castings while retaining useful notch toughness. | 540 | 760 | 14 | 20 HRC | — |
+QT3This page Quenched and tempered, high strength class | Highest-strength Q&T class, for thinner, well-hardenable sections where yield strength and wear dominate over toughness. | 640 | 860 | 11 | 25 HRC | — |
What is G24Mn6 +QT3?
G24Mn6 +QT3 is G24Mn6 heat treated to +QT3 — highest-strength Q&T class, for thinner, well-hardenable sections where yield strength and wear dominate over toughness. G24Mn6 +QT3 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 11% and the elastic modulus is 210 GPa (30.5 Msi). G24Mn6 +QT3 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). +QT1 is the default condition FabDigit quotes; +QT3 is available on request or by drawing note.
Advantages
- High strength — 640 MPa (92.8 ksi), better than 79% of steel grades
Limitations
- Limited ductility — 11%, worse than 89% of steel grades
- Limited formability — 15/100, worse than 87% of steel grades
G24Mn6 +QT3 properties
Typical room-temperature values for G24Mn6 +QT3; 18 are specific to this condition. Other listed values are G24Mn6 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
G24Mn6 +QT3 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
G24Mn6 +QT3 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 11% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
G24Mn6 +QT3 is rated for continuous service to 320°C (608 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
G24Mn6 +QT3 conducts electricity at 9 % IACS, better than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of G24Mn6 +QT3 takes about 24 MJ of energy and emits 2 kg of CO₂ — less than 97% of steel grades. Typical recycled content is 80%.
Manufacturability8
G24Mn6 +QT3's machinability is fair (42/100, worse than 73% of steel grades); weldability fair (48/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with G24Mn6 +QT3
Is G24Mn6 easy to machine?
Machine after heat treatment with carbide tooling at moderate speed; expect abrasive cast skin on the first cut, so take a heavy enough first pass to get under scale and sand inclusions.
Can G24Mn6 be welded?
Weldable with low-hydrogen SMAW/GMAW consumables; CE ≈ 0.5–0.6 so preheat 150–250 °C, control interpass, and post-weld temper (or re-heat-treat) production and repair welds.
Can G24Mn6 be formed, bent or molded?
Sand or investment cast with adequate risering and chills — solidification shrinkage is high; normalize or re-austenitize to break up as-cast dendritic structure before final Q&T.
What surface finishes work on G24Mn6?
Shot-blast to Sa 2½, then zinc-rich primer/paint, metallizing or phosphating; hard chrome or induction hardening is possible on machined bearing faces, anodizing is not applicable.
G24Mn6 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 |
|---|---|---|
| Cgrade-designating carbon level | 0.2 – 0.28 | 0.24 |
| Si | ≤ 0.6 | 0.4 |
| Mnmain strengthening/hardenability addition | 1.2 – 1.6 | 1.4 |
| P | ≤ 0.02 | 0.01 |
| S | ≤ 0.02 | 0.01 |
| Crresidual | ≤ 0.3 | 0.1 |
| Niresidual | ≤ 0.4 | 0.15 |
| Moresidual | ≤ 0.12 | 0.04 |
| Curesidual | ≤ 0.3 | 0.1 |
| Vresidual | ≤ 0.05 | 0.01 |
| Fe | balance | — |
G24Mn6 +QT3 — frequently asked
What is G24Mn6 +QT3 used for?
G24Mn6 +QT3 is typically used for railway castings, structural machine parts and couplers. In short: tougher than plain carbon casts; quench-and-temper impact grade; preheat needed for welding.
What is the yield strength of G24Mn6 +QT3?
G24Mn6 +QT3 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 5 listed tempers.
Is G24Mn6 +QT3 easy to machine?
Not especially — machinability is rated fair (42/100, worse than 73% of steel grades). Machine after heat treatment with carbide tooling at moderate speed; expect abrasive cast skin on the first cut, so take a heavy enough first pass to get under scale and sand inclusions.
Can G24Mn6 +QT3 be welded?
With care — weldability is rated fair (48/100). Weldable with low-hydrogen SMAW/GMAW consumables; CE ≈ 0.5–0.6 so preheat 150–250 °C, control interpass, and post-weld temper (or re-heat-treat) production and repair welds.
What surface finishes work on G24Mn6 +QT3?
Shot-blast to Sa 2½, then zinc-rich primer/paint, metallizing or phosphating; hard chrome or induction hardening is possible on machined bearing faces, anodizing is not applicable.
Can G24Mn6 +QT3 be formed, bent or molded?
Sand or investment cast with adequate risering and chills — solidification shrinkage is high; normalize or re-austenitize to break up as-cast dendritic structure before final Q&T.
What is the maximum service temperature of G24Mn6 +QT3?
G24Mn6 +QT3 is rated for continuous use to about 320°C (608 °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)
- DIN 17182 / DIN 17205 (superseded cast steel grades incl. GS-24Mn6) — DIN (1992)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys (Cast Steels) — ASM International (1990)
- Steel Castings Handbook, 6th ed. — SFSA / ASM International (1995)
- ISO 18265 — Metallic materials: conversion of hardness values — ISO (2013)
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.