Steel SM570-N (Normalized)
Heat-treated state · default condition
JIS SM570
Standard stocked condition: fine uniform grain, best combination of guaranteed yield and low-temperature toughness for bridge and heavy plate.
Values for the N condition
Other SM570 tempers and conditions
SM570 is listed in 4 conditions; see the grade overview at SM570.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
NDefaultThis page Normalized | Standard stocked condition: fine uniform grain, best combination of guaranteed yield and low-temperature toughness for bridge and heavy plate. | 490 | 630 | 24 | 190 HB | — |
As-rolled | Thin gauges (typically ≤16–25 mm) where micro-alloy precipitation alone meets 460 MPa yield; lowest cost. | 500 | 640 | 21 | 12 HRC | 8.6 % IACS |
Thermomechanically controlled processed | Choose for thick weldable plate: lower carbon equivalent means less or no preheat, with excellent toughness and flatness. | 500 | 625 | 25 | 195 HB | — |
Quenched and tempered | Used on heavy sections (>50 mm) to hold the 460 MPa yield class through thickness with tempered-bainite toughness. | 530 | 660 | 23 | 205 HB | — |
What is SM570-N?
SM570-N is SM570 heat treated to N — standard stocked condition: fine uniform grain, best combination of guaranteed yield and low-temperature toughness for bridge and heavy plate. SM570-N has a yield strength of 490 MPa (71.1 ksi) and a tensile strength of 630 MPa (91.4 ksi) — stronger than 61% of steel grades. Elongation at break is 24% and the elastic modulus is 206 GPa (29.9 Msi). SM570-N 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
- Tough — resists crack growth — 125 MPa·√m (113.8 ksi·√in), better than 85% of steel grades
- Readily welded — 72/100, better than 75% of steel grades
Limitations
- Hard to polish — 40/100, worse than 96% of steel grades
SM570-N properties
Typical room-temperature values for SM570-N; 10 are specific to this condition. Other listed values are SM570 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SM570-N 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).
Mechanical16
SM570-N has a yield strength of 490 MPa (71.1 ksi) and a tensile strength of 630 MPa (91.4 ksi) — stronger than 61% of steel grades. Elongation at break is 24% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
SM570-N is rated for continuous service to 350°C (662 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
SM570-N conducts electricity at 8.6 % IACS, better than 66% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of SM570-N takes about 27 MJ of energy and emits 2.2 kg of CO₂ — less than 59% of steel grades. Typical recycled content is 25%.
Manufacturability7
SM570-N's machinability is fair (52/100, better than 52% of steel grades); weldability very good (72/100); formability good (55/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SM570-N
Is SM570 easy to machine?
Machines like a tough 500 MPa-class HSLA plate — use rigid setups, coated carbide at ~120–180 m/min, and expect ~55 % of AISI 1212 tool life.
Can SM570 be welded?
Good weldability by SMAW/FCAW/SAW with 550–620 MPa-class low-hydrogen consumables; preheat 75–150 °C on thick or restrained joints and control interpass to protect the HAZ.
Can SM570 be formed, bent or molded?
Cold bend with inside radius ≥3t across the rolling direction; hot forming should be followed by re-normalizing to restore the guaranteed yield.
What surface finishes work on SM570?
No natural corrosion resistance — shot blast to Sa 2½ then apply zinc-rich epoxy paint systems, metallizing or hot-dip galvanizing (watch silicon level for zinc reactivity).
SM570 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 |
|---|---|---|
| CJIS G 3106 ladle analysis | ≤ 0.18 | 0.16 |
| Si | ≤ 0.55 | 0.35 |
| Mn | ≤ 1.7 | 1.45 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.01 |
| Nboptional micro-alloy addition (Nb+V+Ti total typically ≤0.15 %) | ≤ 0.05 | 0.03 |
| Voptional micro-alloy addition | ≤ 0.1 | 0.04 |
| Tioptional, grain refinement | ≤ 0.03 | 0.02 |
| Fe | balance | — |
SM570-N — frequently asked
What is SM570-N used for?
SM570-N is typically used for bridge girders, high-rise building frames and penstocks. In short: highest-strength JIS structural plate; weldable 570 MPa-class plate; Z35 through-thickness grade available.
What is the yield strength of SM570-N?
SM570-N has a typical yield strength of 490 MPa (71.1 ksi) and a tensile strength of 630 MPa (91.4 ksi) — stronger than 61% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is SM570-N easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Machines like a tough 500 MPa-class HSLA plate — use rigid setups, coated carbide at ~120–180 m/min, and expect ~55 % of AISI 1212 tool life.
Can SM570-N be welded?
Yes — weldability is rated very good (72/100). Good weldability by SMAW/FCAW/SAW with 550–620 MPa-class low-hydrogen consumables; preheat 75–150 °C on thick or restrained joints and control interpass to protect the HAZ.
What surface finishes work on SM570-N?
No natural corrosion resistance — shot blast to Sa 2½ then apply zinc-rich epoxy paint systems, metallizing or hot-dip galvanizing (watch silicon level for zinc reactivity).
Can SM570-N be formed, bent or molded?
Cold bend with inside radius ≥3t across the rolling direction; hot forming should be followed by re-normalizing to restore the guaranteed yield.
What is the maximum service temperature of SM570-N?
SM570-N is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SM570-N and SM570-QT?
N is the default condition — standard stocked condition: fine uniform grain, best combination of guaranteed yield and low-temperature toughness for bridge and heavy plate. QT: used on heavy sections (>50 mm) to hold the 460 MPa yield class through thickness with tempered-bainite toughness. Yield strength is 490 MPa in N versus 530 MPa in QT.
Sources
- JIS G 3106 Rolled steels for welded structure — Japanese Standards Association (2020)
- GB/T 1591 High strength low alloy structural steels (Q460) — SAC (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- Heavy plate for welded structures (SM570 / TMCP grades) — JFE Steel / Nippon Steel (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.