Steel A356 Grade 10-QT (Quenched and tempered)
Heat-treated state · default condition
ASTM A356 Grade 10 · UNS J22090
Standard supply condition for turbine casings and valve bodies needing full spec strength plus good toughness in thick sections.
Values for the QT condition
Other A356 Grade 10 tempers and conditions
A356 Grade 10 is listed in 3 conditions; see the grade overview at A356 Grade 10.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
normalized and tempered | Chosen for very heavy or complex castings where liquid quenching risks distortion/cracking; slightly lower strength, easier to machine. | 430 | 600 | 20 | 11 HRC | 7.7 % IACS |
Q&T + post-weld stress relief | Applies to castings that were weld-repaired after heat treatment; a sub-critical stress relief slightly softens the matrix but restores toughness at repairs. | 470 | 630 | 19 | 14 HRC | 7.5 % IACS |
QTDefaultThis page Quenched and tempered | Standard supply condition for turbine casings and valve bodies needing full spec strength plus good toughness in thick sections. | 500 | 655 | 18 | 18 HRC | — |
What is A356 Grade 10-QT?
A356 Grade 10-QT is A356 Grade 10 heat treated to QT — standard supply condition for turbine casings and valve bodies needing full spec strength plus good toughness in thick sections. A356 Grade 10-QT has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 63% of steel grades. Elongation at break is 18% and the elastic modulus is 207 GPa (30 Msi). A356 Grade 10-QT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Advantages
- High service temperature — 510°C (950 °F), better than 92% of steel grades
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
Limitations
- Limited formability — 10/100, worse than 95% of steel grades
A356 Grade 10-QT properties
Typical room-temperature values for A356 Grade 10-QT; 11 are specific to this condition. Other listed values are A356 Grade 10 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A356 Grade 10-QT has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical14
A356 Grade 10-QT has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 63% of steel grades. Elongation at break is 18% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
A356 Grade 10-QT is rated for continuous service to 510°C (950 °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
A356 Grade 10-QT conducts electricity at 7.5 % IACS, worse than 67% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of A356 Grade 10-QT takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 80%.
Manufacturability8
A356 Grade 10-QT's machinability is fair (48/100, worse than 57% of steel grades); weldability fair (45/100); 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 A356 Grade 10-QT
Is A356 Grade 10 easy to machine?
Machine in the tempered condition at ~180–220 HB with rigid setups and carbide tooling; expect ~50 % of AISI 1212 rates and allow generous stock for cast-skin and riser areas.
Can A356 Grade 10 be welded?
Weldable with matching Ni-Cr-Mo-V or 2.25Cr-1Mo low-hydrogen consumables; preheat 200–300 °C, maintain interpass and apply PWHT at ~660–700 °C to avoid hydrogen and reheat cracking.
Can A356 Grade 10 be formed, bent or molded?
Supplied only as sand/no-bake castings — design generous fillets, directional solidification and adequate risering for heavy sections; no cold forming.
What surface finishes work on A356 Grade 10?
Shot blast, then phosphate + high-temperature aluminium paint or metal-spray coating; not anodizable and must be protected from wet-steam corrosion during layup.
A356 Grade 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 |
|---|---|---|
| Ccarbon kept low for weldability of heavy sections | ≤ 0.2 | 0.16 |
| Mn | 0.5 – 0.9 | 0.7 |
| Si | ≤ 0.6 | 0.35 |
| Prestricted to limit temper embrittlement | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Nirange varies with edition/purchaser agreement | 0.7 – 1.6 | 1.1 |
| Cr | 0.9 – 1.5 | 1.2 |
| Mocreep strength | 1 – 1.5 | 1.2 |
| Vcarbide precipitation strengthening | 0.2 – 0.3 | 0.25 |
| Fe | balance | — |
A356 Grade 10-QT — frequently asked
What is A356 Grade 10-QT used for?
A356 Grade 10-QT is typically used for steam turbine rotors, high-strength turbine casings and generator components. In short: highest strength A356 grade; ni-Cr-Mo-V quench and temper; lower ceiling: 510 °C.
What is the yield strength of A356 Grade 10-QT?
A356 Grade 10-QT has a typical yield strength of 500 MPa (72.5 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 63% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is A356 Grade 10-QT easy to machine?
Reasonably — machinability is rated fair (48/100, worse than 57% of steel grades). Machine in the tempered condition at ~180–220 HB with rigid setups and carbide tooling; expect ~50 % of AISI 1212 rates and allow generous stock for cast-skin and riser areas.
Can A356 Grade 10-QT be welded?
With care — weldability is rated fair (45/100). Weldable with matching Ni-Cr-Mo-V or 2.25Cr-1Mo low-hydrogen consumables; preheat 200–300 °C, maintain interpass and apply PWHT at ~660–700 °C to avoid hydrogen and reheat cracking.
What surface finishes work on A356 Grade 10-QT?
Shot blast, then phosphate + high-temperature aluminium paint or metal-spray coating; not anodizable and must be protected from wet-steam corrosion during layup.
Can A356 Grade 10-QT be formed, bent or molded?
Supplied only as sand/no-bake castings — design generous fillets, directional solidification and adequate risering for heavy sections; no cold forming.
What is the maximum service temperature of A356 Grade 10-QT?
A356 Grade 10-QT is rated for continuous use to about 510°C (950 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A356 Grade 10-QT and A356 Grade 10-NT?
QT is the default condition — standard supply condition for turbine casings and valve bodies needing full spec strength plus good toughness in thick sections. NT: chosen for very heavy or complex castings where liquid quenching risks distortion/cracking; slightly lower strength, easier to machine. Yield strength is 500 MPa in QT versus 430 MPa in NT.
Sources
- ASTM A356/A356M — Steel Castings, Carbon, Low-Alloy, and Stainless Steel, Heavy-Walled for Steam Turbines — ASTM International (2023)
- ASTM A703/A703M — General Requirements for Steel Castings for Pressure-Containing Parts — ASTM International (2022)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 15 — Casting — ASM International (2008)
- ASTM A488/A488M — Qualification of Procedures and Personnel for Welding of Steel Castings — ASTM International (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.