Steel G17Mn5 +QT (Quenched and tempered)
Heat-treated state · default condition
EN 1.1131
Standard pressure-casting condition: best combination of 240 MPa yield and -40 °C notch toughness.
Values for the +QT condition
Other G17Mn5 tempers and conditions
G17Mn5 is listed in 5 conditions; see the grade overview at G17Mn5.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Only for non-pressure structural parts; coarse as-cast structure gives low and scattered toughness and is not EN 10213 compliant. | 240 | 470 | 20 | 150 HB | 8.5 % IACS |
Normalized | Simple grain-refining treatment used for non-critical or general engineering castings of this grade. | 255 | 490 | 26 | 145 HB | 8.6 % IACS |
Normalized and tempered | Economical alternative to +QT for thinner walls where -40 °C toughness margin is less critical. | 265 | 500 | 27 | 148 HB | 8.6 % IACS |
Stress relieved | Applied after major weld repair or heavy machining to relieve residual stress; mechanicals close to the prior +QT/+NT state with slightly lower yield. | 270 | 505 | 28 | 150 HB | 8.6 % IACS |
+QTDefaultThis page Quenched and tempered | Standard pressure-casting condition: best combination of 240 MPa yield and -40 °C notch toughness. | 280 | 520 | 28 | 155 HB | — |
What is G17Mn5 +QT?
G17Mn5 +QT is G17Mn5 heat treated to +QT — standard pressure-casting condition: best combination of 240 MPa yield and -40 °C notch toughness. G17Mn5 +QT has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 90% of steel grades. Elongation at break is 28% and the elastic modulus is 210 GPa (30.5 Msi). G17Mn5 +QT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,465°C (2,669 °F).
Advantages
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
- Readily welded — 82/100, better than 81% of steel grades
Limitations
- Low strength — 280 MPa (40.6 ksi), worse than 90% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
- Limited formability — 20/100, worse than 80% of steel grades
G17Mn5 +QT properties
Typical room-temperature values for G17Mn5 +QT; 11 are specific to this condition. Other listed values are G17Mn5 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
G17Mn5 +QT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,465°C (2,669 °F).
Mechanical15
G17Mn5 +QT has a yield strength of 280 MPa (40.6 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 90% of steel grades. Elongation at break is 28% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
G17Mn5 +QT is rated for continuous service to 400°C (752 °F). It conducts heat at 47 W/m·K (27.2 BTU/hr·ft·°F), better than 75% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical2
G17Mn5 +QT has an electrical resistivity of 2×10⁻⁷ Ω·m.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of G17Mn5 +QT takes about 24 MJ of energy and emits 2 kg of CO₂ — less than 97% of steel grades. Typical recycled content is 85%.
Manufacturability8
G17Mn5 +QT's machinability is good (58/100, better than 75% of steel grades); weldability very good (82/100); formability poor (20/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with G17Mn5 +QT
Is G17Mn5 easy to machine?
Machines like soft C-Mn steel but can be gummy below ~150 HB — use positive-rake carbide, moderate speed and heavy feed to break the chip; watch for hard skin and residual sand on unmachined faces.
Can G17Mn5 be welded?
Excellent weldability (CE ≈ 0.40): SMAW/GTAW/SAW with low-hydrogen consumables, 100–150 °C preheat for heavy sections, PWHT at 550–620 °C for pressure parts and major repairs.
Can G17Mn5 be formed, bent or molded?
Green-sand or no-bake sand casting; needs generous risering and chills due to steel's high shrinkage (~2 %), high pour temperature (~1580–1620 °C) and long solidification range — avoid sharp internal fillets.
What surface finishes work on G17Mn5?
No anodizing; shot blast then epoxy/zinc-rich primer, phosphate, or Ni/Cr plating for corrosion protection; can be nitrided only for light wear duty.
G17Mn5 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 |
|---|---|---|
| C0.17 % nominal gives the grade its name | 0.15 – 0.2 | 0.17 |
| Si | ≤ 0.6 | 0.4 |
| Mn | 1 – 1.6 | 1.3 |
| P | ≤ 0.02 | 0.01 |
| S | ≤ 0.02 | 0.01 |
| Crresidual element | ≤ 0.3 | 0.1 |
| Niresidual element | ≤ 0.8 | 0.2 |
| Moresidual element | ≤ 0.12 | 0.03 |
| Curesidual element | ≤ 0.3 | 0.1 |
| Vresidual element | ≤ 0.05 | 0.01 |
| Fe | balance | — |
G17Mn5 +QT — frequently asked
What is G17Mn5 +QT used for?
G17Mn5 +QT is typically used for pressure vessel castings, valve bodies for low-temperature service and piping components. In short: best low-temperature toughness; highly weldable cast steel; high ductility, moderate strength.
What is the yield strength of G17Mn5 +QT?
G17Mn5 +QT has a typical yield strength of 280 MPa (40.6 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 90% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is G17Mn5 +QT easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like soft C-Mn steel but can be gummy below ~150 HB — use positive-rake carbide, moderate speed and heavy feed to break the chip; watch for hard skin and residual sand on unmachined faces.
Can G17Mn5 +QT be welded?
Yes — weldability is rated very good (82/100). Excellent weldability (CE ≈ 0.40): SMAW/GTAW/SAW with low-hydrogen consumables, 100–150 °C preheat for heavy sections, PWHT at 550–620 °C for pressure parts and major repairs.
What surface finishes work on G17Mn5 +QT?
No anodizing; shot blast then epoxy/zinc-rich primer, phosphate, or Ni/Cr plating for corrosion protection; can be nitrided only for light wear duty.
Can G17Mn5 +QT be formed, bent or molded?
Green-sand or no-bake sand casting; needs generous risering and chills due to steel's high shrinkage (~2 %), high pour temperature (~1580–1620 °C) and long solidification range — avoid sharp internal fillets.
What is the maximum service temperature of G17Mn5 +QT?
G17Mn5 +QT 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 G17Mn5 +QT and G17Mn5-F?
+QT is the default condition — standard pressure-casting condition: best combination of 240 MPa yield and -40 °C notch toughness. F: only for non-pressure structural parts; coarse as-cast structure gives low and scattered toughness and is not EN 10213 compliant. Yield strength is 280 MPa in +QT versus 240 MPa in F.
Sources
- EN 10213 — Steel castings for pressure purposes — CEN (2016)
- GB/T 16253 — (pressure-purpose steel castings, ZG20Mn) — SAC (2019)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America / ASM (1995)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASTM A352/A216 (equivalent low-temperature / general carbon steel castings) — ASTM (2018)
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.