Steel A515 Grade 70-N (Normalized)
Heat-treated state
ASTM A515 Grade 70 · UNS K02901
Required for heavy plate and whenever improved notch toughness and uniform through-thickness properties are needed.
Values for the N condition
Other A515 Grade 70 tempers and conditions
A515 Grade 70 is listed in 5 conditions; see the grade overview at A515 Grade 70.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Stress relieved | Used for thinner plate that must be machined flat or is cold-formed, where residual stress control matters more than toughness. | 290 | 520 | 26 | 148 HB | 10.5 % IACS |
Normalized and stress relieved / simulated PWHT | Ordered when the vessel will see one or more PWHT cycles and the mill must certify properties after simulated heat treatment. | 295 | 515 | 28 | 145 HB | 10.5 % IACS |
ARDefault As-rolled | Standard stock condition for plate up to about 50 mm where no impact or PWHT-simulation requirements apply. | 300 | 540 | 25 | 155 HB | — |
NThis page Normalized | Required for heavy plate and whenever improved notch toughness and uniform through-thickness properties are needed. | 310 | 530 | 27 | 150 HB | — |
normalized, Charpy V-notch impact tested (supplementary requirement) | Choose when ASME UCS-66 impact exemption cannot be claimed and certified CVN energy at a stated test temperature is required. | 310 | 530 | 27 | 150 HB | 10.5 % IACS |
What is A515 Grade 70-N?
A515 Grade 70-N is A515 Grade 70 heat treated to N — required for heavy plate and whenever improved notch toughness and uniform through-thickness properties are needed. A515 Grade 70-N has a yield strength of 310 MPa (45 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 83% of steel grades. Elongation at break is 27% and the elastic modulus is 200 GPa (29 Msi). A515 Grade 70-N has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,430°C (2,606 °F). AR is the default condition FabDigit quotes; N is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 140 MPa·√m (127.4 ksi·√in), better than 94% of steel grades
- Conducts heat well — 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High electrical conductivity — 10.5 % IACS, better than 89% of steel grades
- Ductile — tolerates forming and impact — 27%, better than 86% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
- Low strength — 310 MPa (45 ksi), worse than 83% of steel grades
A515 Grade 70-N properties
Typical room-temperature values for A515 Grade 70-N; 11 are specific to this condition. Other listed values are A515 Grade 70 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
A515 Grade 70-N has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,430°C (2,606 °F).
Mechanical16
A515 Grade 70-N has a yield strength of 310 MPa (45 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 83% of steel grades. Elongation at break is 27% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
A515 Grade 70-N is rated for continuous service to 425°C (797 °F). It conducts heat at 51 W/m·K (29.5 BTU/hr·ft·°F), better than 92% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
A515 Grade 70-N conducts electricity at 10.5 % IACS, better than 89% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of A515 Grade 70-N takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability6
A515 Grade 70-N's machinability is good (60/100, better than 83% of steel grades); weldability excellent (85/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with A515 Grade 70-N
Is A515 Grade 70 easy to machine?
Machines like 1025–1030 hot-rolled plate: use rigid setups, ~60 % of 1212 speeds, and expect gummy chips — a stress-relief before finish machining prevents distortion in thick sections.
Can A515 Grade 70 be welded?
Excellent weldability with SMAW/SAW/GMAW using E7018 or F7A2-EM12K class consumables; preheat 100–150 °C above ~38 mm or high carbon heats, and PWHT at 595–650 °C per ASME VIII when thickness or service demands.
Can A515 Grade 70 be formed, bent or molded?
Hot form or dish above 900 °C and re-normalize if heated into the critical range; cold forming beyond ~5 % extreme-fibre strain calls for post-form heat treatment per UCS-79.
What surface finishes work on A515 Grade 70?
No inherent corrosion protection — shot-blast to SA 2½ and apply epoxy/zinc primer, cladding or a corrosion allowance; hot-dip galvanizing works but hot-forming/PWHT sequence must precede it.
A515 Grade 70 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 |
|---|---|---|
| C0.31 max for ≤25 mm; increases stepwise to 0.35 max for thick plate (heat analysis, ASTM A515/A515M) | ≤ 0.35 | 0.28 |
| Mnheat analysis max; 1.20 max on product analysis basis for heavier plate | ≤ 0.9 | 0.8 |
| Sisilicon-killed, coarse austenitic grain practice | 0.15 – 0.4 | 0.25 |
| P | ≤ 0.04 | 0.02 |
| S≤0.002–0.005 typical for HIC-tested plate | ≤ 0.04 | 0.01 |
| Fe | balance | — |
A515 Grade 70-N — frequently asked
What is A515 Grade 70-N used for?
A515 Grade 70-N is typically used for boiler drums, pressure vessels, storage tanks and process equipment. In short: code-listed vessel plate; weldable at 540 MPa; coarse-grain alternative to A516.
What is the yield strength of A515 Grade 70-N?
A515 Grade 70-N has a typical yield strength of 310 MPa (45 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 83% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is A515 Grade 70-N easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machines like 1025–1030 hot-rolled plate: use rigid setups, ~60 % of 1212 speeds, and expect gummy chips — a stress-relief before finish machining prevents distortion in thick sections.
Can A515 Grade 70-N be welded?
Yes — weldability is rated excellent (85/100). Excellent weldability with SMAW/SAW/GMAW using E7018 or F7A2-EM12K class consumables; preheat 100–150 °C above ~38 mm or high carbon heats, and PWHT at 595–650 °C per ASME VIII when thickness or service demands.
What surface finishes work on A515 Grade 70-N?
No inherent corrosion protection — shot-blast to SA 2½ and apply epoxy/zinc primer, cladding or a corrosion allowance; hot-dip galvanizing works but hot-forming/PWHT sequence must precede it.
Can A515 Grade 70-N be formed, bent or molded?
Hot form or dish above 900 °C and re-normalize if heated into the critical range; cold forming beyond ~5 % extreme-fibre strain calls for post-form heat treatment per UCS-79.
What is the maximum service temperature of A515 Grade 70-N?
A515 Grade 70-N 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.
What is the difference between A515 Grade 70-AR and A515 Grade 70-N?
AR is the default condition — standard stock condition for plate up to about 50 mm where no impact or PWHT-simulation requirements apply. N: required for heavy plate and whenever improved notch toughness and uniform through-thickness properties are needed. Yield strength is 300 MPa in AR versus 310 MPa in N.
Sources
- ASTM A515/A515M — Pressure Vessel Plates, Carbon Steel, for Intermediate- and Higher-Temperature Service — ASTM International (2020)
- ASTM A20/A20M — General Requirements for Steel Plates for Pressure Vessels — ASTM International (2020)
- ASME BPVC Section II Part D — Properties (Metric) — ASME (2023)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- GB/T 713 — Steel plates for boilers and pressure vessels (Q245R/Q345R) — SAC (2014)
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.