Steel A356 Grade 2 Q&T (Quenched and tempered)
Heat-treated state
ASTM A356 Grade 2 · UNS J12523
Used when the purchaser wants the upper end of the strength/toughness band in moderate wall thicknesses; needs a high temper to stay within the specified yield range.
Values for the Q&T condition
Other A356 Grade 2 tempers and conditions
A356 Grade 2 is listed in 4 conditions; see the grade overview at A356 Grade 2.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full anneal (furnace cooled) | Chosen for very thick sections or when maximum machinability, dimensional stability and low residual stress matter more than strength. | 275 | 500 | 29 | 143 HB | 9 % IACS |
N+T + PWHT / stress relieved | Condition delivered after weld repair of the casting or after fabrication welding; post-weld heat treatment restores toughness in the HAZ. | 295 | 510 | 25 | 150 HB | 9 % IACS |
N+TDefault Normalized and tempered | Standard supply condition for heavy-wall turbine/valve castings: best combination of strength, toughness and creep behaviour. | 305 | 525 | 26 | 155 HB | 9 % IACS |
Q&TThis page Quenched and tempered | Used when the purchaser wants the upper end of the strength/toughness band in moderate wall thicknesses; needs a high temper to stay within the specified yield range. | 370 | 570 | 24 | 175 HB | 8.5 % IACS |
What is A356 Grade 2 Q&T?
A356 Grade 2 Q&T is A356 Grade 2 heat treated to Q&T — used when the purchaser wants the upper end of the strength/toughness band in moderate wall thicknesses; needs a high temper to stay within the specified yield range. A356 Grade 2 Q&T has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 70% of steel grades. Elongation at break is 24% and the elastic modulus is 205 GPa (29.7 Msi). A356 Grade 2 Q&T has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,440°C (2,624 °F). N+T is the default condition FabDigit quotes; Q&T is available on request or by drawing note.
Advantages
- High service temperature — 450°C (842 °F), better than 86% of steel grades
- Tough — resists crack growth — 125 MPa·√m (113.8 ksi·√in), better than 85% of steel grades
Limitations
- Limited formability — 12/100, worse than 92% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
A356 Grade 2 Q&T properties
Typical room-temperature values for A356 Grade 2 Q&T; 22 are specific to this condition. Other listed values are A356 Grade 2 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A356 Grade 2 Q&T has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,440°C (2,624 °F).
Mechanical16
A356 Grade 2 Q&T has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 70% of steel grades. Elongation at break is 24% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
A356 Grade 2 Q&T is rated for continuous service to 450°C (842 °F). It conducts heat at 41 W/m·K (23.7 BTU/hr·ft·°F), worse than 62% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
A356 Grade 2 Q&T conducts electricity at 8.5 % IACS, better than 63% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of A356 Grade 2 Q&T takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 80%.
Manufacturability7
A356 Grade 2 Q&T's machinability is fair (50/100, worse than 53% of steel grades); weldability good (60/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A356 Grade 2 Q&T
Is A356 Grade 2 easy to machine?
Machines like normalized 4130-class steel at ~60 % of 1212; use rigid setups, carbide inserts and expect harder skin/chill zones on casting surfaces.
Can A356 Grade 2 be welded?
Readily welded with matched C-1/2Mo consumables (E7018-A1 / ER80S-D2); preheat 150–200 °C and PWHT at 620–680 °C for weld repairs and thick sections.
Can A356 Grade 2 be formed, bent or molded?
Sand-cast product with good fluidity; heavy walls need generous risering, chills and controlled solidification to avoid shrinkage porosity and hot tears.
What surface finishes work on A356 Grade 2?
Not anodizable; protect by shot blast plus epoxy/aluminium metallizing, or leave bare inside dry-steam service where oxide film is stable.
A356 Grade 2 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 | ≤ 0.25 | 0.22 |
| Si | ≤ 0.6 | 0.4 |
| Mn | ≤ 0.7 | 0.6 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.03 | 0.02 |
| Moprovides elevated-temperature strength | 0.45 – 0.65 | 0.55 |
| Fe | balance | — |
A356 Grade 2 Q&T — frequently asked
What is A356 Grade 2 Q&T used for?
A356 Grade 2 Q&T is typically used for steam turbine casings, valve bodies and pressure vessel heads. In short: C-1/2Mo pressure casting; heavy-wall turbine grade; service to 470 °C.
What is the yield strength of A356 Grade 2 Q&T?
A356 Grade 2 Q&T has a typical yield strength of 370 MPa (53.7 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 70% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is A356 Grade 2 Q&T easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machines like normalized 4130-class steel at ~60 % of 1212; use rigid setups, carbide inserts and expect harder skin/chill zones on casting surfaces.
Can A356 Grade 2 Q&T be welded?
Yes — weldability is rated good (60/100). Readily welded with matched C-1/2Mo consumables (E7018-A1 / ER80S-D2); preheat 150–200 °C and PWHT at 620–680 °C for weld repairs and thick sections.
What surface finishes work on A356 Grade 2 Q&T?
Not anodizable; protect by shot blast plus epoxy/aluminium metallizing, or leave bare inside dry-steam service where oxide film is stable.
Can A356 Grade 2 Q&T be formed, bent or molded?
Sand-cast product with good fluidity; heavy walls need generous risering, chills and controlled solidification to avoid shrinkage porosity and hot tears.
What is the maximum service temperature of A356 Grade 2 Q&T?
A356 Grade 2 Q&T is rated for continuous use to about 450°C (842 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM A356/A356M — Steel Castings, Carbon, Low Alloy, and Stainless Steel, Heavy-Walled for Steam Turbines — ASTM International (2021)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Steel Castings Handbook, 6th ed. — Steel Founders' Society of America / ASM (1995)
- ASME BPVC Section II Part D — Material Properties (C-1/2Mo) — ASME (2023)
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.