Steel A356 Grade 1 N+T
Heat-treated state · default condition
ASTM A356 Grade 1 · UNS J03502
N+T = normalized and tempered
Standard supply condition: best balance of strength, ductility and notch toughness for pressure-containing steam-turbine and valve castings.
Values for the N+T condition
Other A356 Grade 1 tempers and conditions
A356 Grade 1 is listed in 3 conditions; see the grade overview at A356 Grade 1.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full anneal (austenitize + slow furnace cool) | Choose for maximum dimensional stability, lowest residual stress and easiest machining of very heavy, complex turbine casings. | 275 | 500 | 28 | 143 HB | 10 % IACS |
N+TDefaultThis page Normalized and tempered | Standard supply condition: best balance of strength, ductility and notch toughness for pressure-containing steam-turbine and valve castings. | 300 | 520 | 26 | 150 HB | — |
Quenched and tempered | Choose when higher yield strength and lower-temperature toughness are needed; effective only in moderate wall thickness because of the low hardenability of plain carbon steel. | 350 | 560 | 24 | 170 HB | — |
What is A356 Grade 1 N+T?
A356 Grade 1 N+T is A356 Grade 1 heat treated to N+T — standard supply condition: best balance of strength, ductility and notch toughness for pressure-containing steam-turbine and valve castings. A356 Grade 1 N+T has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 86% of steel grades. Elongation at break is 26% and the elastic modulus is 200 GPa (29 Msi). A356 Grade 1 N+T 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).
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Conducts heat well — 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
- Readily welded — 78/100, better than 78% of steel grades
Limitations
- Low strength — 300 MPa (43.5 ksi), worse than 86% of steel grades
- Limited formability — 20/100, worse than 80% of steel grades
A356 Grade 1 N+T properties
Typical room-temperature values for A356 Grade 1 N+T; 11 are specific to this condition. Other listed values are A356 Grade 1 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A356 Grade 1 N+T 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).
Mechanical15
A356 Grade 1 N+T has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 86% of steel grades. Elongation at break is 26% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
A356 Grade 1 N+T is rated for continuous service to 425°C (797 °F). It conducts heat at 50 W/m·K (28.9 BTU/hr·ft·°F), better than 87% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
A356 Grade 1 N+T conducts electricity at 10 % IACS, better than 83% 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 1 N+T takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 80%.
Manufacturability8
A356 Grade 1 N+T's machinability is good (60/100, better than 83% of steel grades); weldability very good (78/100); 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 A356 Grade 1 N+T
Is A356 Grade 1 easy to machine?
Machines like normalized 1025–1030 steel at ~70 % of AISI 1212; use rigid setups and expect hard spots from chill or unmachined casting skin.
Can A356 Grade 1 be welded?
Readily weldable/weld-repairable with E7018 or ER70S-x; preheat 100–200 °C for heavy sections and post-weld heat treat per ASTM A356 to restore properties.
Can A356 Grade 1 be formed, bent or molded?
Sand-cast grade with good fluidity but ~2 % solidification shrinkage — needs generous risering, chills at thick junctions and gradual wall transitions.
What surface finishes work on A356 Grade 1?
Not anodizable; protect by shot blast plus epoxy/zinc-rich paint, thermal spray or weld overlay; phosphating suits machined mating faces.
A356 Grade 1 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 |
|---|---|---|
| Cmax per ASTM A356 Grade 1 | ≤ 0.35 | 0.25 |
| Mn | ≤ 0.7 | 0.6 |
| Si | ≤ 0.6 | 0.4 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.03 | 0.02 |
| Niresidual limit | ≤ 0.5 | — |
| Crresidual limit | ≤ 0.35 | — |
| Moresidual limit | ≤ 0.25 | — |
| Fe | balance | — |
A356 Grade 1 N+T — frequently asked
What is A356 Grade 1 N+T used for?
A356 Grade 1 N+T is typically used for steam turbine casings, valve bodies, heavy-wall pressure vessel castings and power plant components. In short: heavy-section pressure castings; turbine casing steel; weld-repairable thick walls.
What is the yield strength of A356 Grade 1 N+T?
A356 Grade 1 N+T has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 86% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is A356 Grade 1 N+T easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machines like normalized 1025–1030 steel at ~70 % of AISI 1212; use rigid setups and expect hard spots from chill or unmachined casting skin.
Can A356 Grade 1 N+T be welded?
Yes — weldability is rated very good (78/100). Readily weldable/weld-repairable with E7018 or ER70S-x; preheat 100–200 °C for heavy sections and post-weld heat treat per ASTM A356 to restore properties.
What surface finishes work on A356 Grade 1 N+T?
Not anodizable; protect by shot blast plus epoxy/zinc-rich paint, thermal spray or weld overlay; phosphating suits machined mating faces.
Can A356 Grade 1 N+T be formed, bent or molded?
Sand-cast grade with good fluidity but ~2 % solidification shrinkage — needs generous risering, chills at thick junctions and gradual wall transitions.
What is the maximum service temperature of A356 Grade 1 N+T?
A356 Grade 1 N+T is rated for continuous use to about 425°C (797 °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)
- ASM Handbook Vol. 15 — Casting — ASM International (2008)
- ASME BPVC Section II Part D — Material Properties — ASME (2023)
- Mysteel / 1688 (2026)
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.