Steel 20G N+T
Heat-treated state
N+T = normalized and tempered
Used for heavier-wall headers and thick plate to relieve stress and stabilize toughness after normalizing.
Values for the N+T condition
Other 20G tempers and conditions
20G is listed in 6 conditions; see the grade overview at 20G.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest condition, chosen when maximum cold bending/expanding formability is needed before final normalizing. | 250 | 430 | 33 | 120 HB | 11 % IACS |
N+TThis page Normalized and tempered | Used for heavier-wall headers and thick plate to relieve stress and stabilize toughness after normalizing. | 270 | 455 | 30 | 130 HB | 11 % IACS |
NDefault Normalized | Standard delivery condition for 20G boiler tube and plate: fine uniform ferrite-pearlite, best toughness/creep consistency. | 275 | 470 | 28 | 135 HB | — |
Hot rolled | As-rolled or hot-finished plate/tube for lower-duty pressure parts; slightly higher hardness and more property scatter than normalized. | 280 | 480 | 26 | 143 HB | 11 % IACS |
Cold drawn tube, then normalized | Small-diameter, close-tolerance boiler tubing: cold drawn for size/surface then normalized to restore code properties. | 285 | 480 | 27 | 140 HB | 11 % IACS |
Cold drawn | As-drawn strain-hardened stock for mechanical (non-pressure) use where strength and tolerance matter more than toughness. | 450 | 560 | 14 | 170 HB | 10.5 % IACS |
What is 20G N+T?
20G N+T is 20G heat treated to N+T — used for heavier-wall headers and thick plate to relieve stress and stabilize toughness after normalizing. 20G N+T has a yield strength of 270 MPa (39.2 ksi) and a tensile strength of 455 MPa (66 ksi) — weaker than 91% of steel grades. Elongation at break is 30% and the elastic modulus is 210 GPa (30.5 Msi). 20G N+T has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F). N is the default condition FabDigit quotes; N+T is available on request or by drawing note.
Advantages
- High electrical conductivity — 11 % IACS, better than 98% of steel grades
- Easy to machine — 66/100, better than 95% of steel grades
- Forms and bends easily — 84/100, better than 94% of steel grades
- Ductile — tolerates forming and impact — 30%, better than 93% of steel grades
- Readily welded — 92/100, better than 93% of steel grades
Limitations
- Low strength — 270 MPa (39.2 ksi), worse than 91% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
20G N+T properties
Typical room-temperature values for 20G N+T; 22 are specific to this condition. Other listed values are 20G reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
20G N+T has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F).
Mechanical16
20G N+T has a yield strength of 270 MPa (39.2 ksi) and a tensile strength of 455 MPa (66 ksi) — weaker than 91% of steel grades. Elongation at break is 30% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20G N+T is rated for continuous service to 450°C (842 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 12.1 µm/m·K (6.72 µin/in·°F).
Electrical3
20G N+T conducts electricity at 11 % IACS, better than 98% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 20G N+T takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
20G N+T's machinability is good (66/100, better than 95% of steel grades); weldability excellent (92/100); formability very good (84/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 20G N+T
Is 20G easy to machine?
Machines like AISI 1020 (≈65 % of 1212): gummy chips in the annealed state, use sharp positive tooling, generous feed and coolant; normalized stock gives cleaner surfaces.
Can 20G be welded?
Excellent weldability (CEV ≈ 0.35); GTAW root + SMAW/GMAW fill with E7015/ER50-6 class consumables, preheat 100–150 °C only for wall >20 mm, PWHT per boiler code for thick joints.
Can 20G be formed, bent or molded?
Very good cold bending, tube expanding and flaring; hot forming 850–1050 °C followed by re-normalizing at 890–920 °C to restore grain size.
What surface finishes work on 20G?
No corrosion resistance of its own — protect by phosphating, high-temperature aluminium/silicone paint, shot blast plus primer, or internal magnetite film from controlled boiler water; not anodizable.
20G 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 |
|---|---|---|
| C0.17–0.24 in some plate editions | 0.17 – 0.23 | 0.2 |
| Si | 0.17 – 0.37 | 0.25 |
| Mn | 0.35 – 0.65 | 0.5 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.02 | 0.01 |
| Crresidual | ≤ 0.25 | 0.05 |
| Niresidual | ≤ 0.25 | 0.05 |
| Curesidual | ≤ 0.2 | 0.05 |
| Moresidual | ≤ 0.15 | 0.02 |
| Fe | balance | — |
20G N+T — frequently asked
What is 20G N+T used for?
20G N+T is typically used for boiler drums, steam headers and pressure parts. In short: code-grade boiler plate; excellent weldability, low cost; 450 °C service ceiling.
What is the yield strength of 20G N+T?
20G N+T has a typical yield strength of 270 MPa (39.2 ksi) and a tensile strength of 455 MPa (66 ksi) — weaker than 91% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 20G N+T easy to machine?
Reasonably — machinability is rated good (66/100, better than 95% of steel grades). Machines like AISI 1020 (≈65 % of 1212): gummy chips in the annealed state, use sharp positive tooling, generous feed and coolant; normalized stock gives cleaner surfaces.
Can 20G N+T be welded?
Yes — weldability is rated excellent (92/100). Excellent weldability (CEV ≈ 0.35); GTAW root + SMAW/GMAW fill with E7015/ER50-6 class consumables, preheat 100–150 °C only for wall >20 mm, PWHT per boiler code for thick joints.
What surface finishes work on 20G N+T?
No corrosion resistance of its own — protect by phosphating, high-temperature aluminium/silicone paint, shot blast plus primer, or internal magnetite film from controlled boiler water; not anodizable.
Can 20G N+T be formed, bent or molded?
Very good cold bending, tube expanding and flaring; hot forming 850–1050 °C followed by re-normalizing at 890–920 °C to restore grain size.
What is the maximum service temperature of 20G N+T?
20G N+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.
What is the difference between 20G-N and 20G-CD?
N is the default condition — standard delivery condition for 20G boiler tube and plate: fine uniform ferrite-pearlite, best toughness/creep consistency. CD: as-drawn strain-hardened stock for mechanical (non-pressure) use where strength and tolerance matter more than toughness. Yield strength is 275 MPa in N versus 450 MPa in CD.
Sources
- GB/T 5310 Seamless steel tubes and pipes for high pressure boiler (2017)
- GB 713 Steel plates for boilers and pressure vessels (grade 20g, superseded by Q245R) — SAC (1997)
- ASTM A515/A515M Grade 60 — Pressure Vessel Plates, Carbon Steel — ASTM International (2020)
- ASTM A210/A210M Grade A-1 — Seamless Medium-Carbon Steel Boiler Tubes — ASTM International (2019)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels — ASM International (1990)
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.