Steel 20G
20G is a low-carbon boiler and pressure-vessel plate steel of the A515 Gr 60 class, strengthened by carbon and normalizing rather than by alloy additions.
Reference datasheet — 20G is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the N condition
20G tempers and conditions
20G is supplied in 6 conditions, soft to hard. N is the default FabDigit quotes; the values on this page are for it.
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 |
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?
20G is a low-carbon boiler and pressure-vessel plate steel of the A515 Gr 60 class, strengthened by carbon and normalizing rather than by alloy additions. In the default normalized condition it gives 275 MPa yield, 470 MPa tensile, 28 % elongation and about 135 HB (74 HRB), with a service ceiling of roughly 450 °C, and it is available hot-rolled, normalized, normalized-and-tempered, annealed or cold-drawn for plate, tube and pressure parts. Its weldability (score 92) and formability (score 82) are the reasons it is specified, but it has no corrosion resistance of its own and depends on coatings or controlled boiler water. For vessel shells at moderate temperature, 20R (A516 Gr 60) is the nearest alternative. 20G 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). 20G has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 91% of steel grades. Elongation at break is 28% and the elastic modulus is 210 GPa (30.5 Msi).
What is 20G used for?
- boiler drums
- steam headers
- pressure parts
Advantages
- High electrical conductivity — 11 % IACS, better than 98% of steel grades
- Forms and bends easily — 82/100, better than 94% of steel grades
- Easy to machine — 65/100, better than 93% of steel grades
- Readily welded — 92/100, better than 93% of steel grades
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
Limitations
- Low strength — 275 MPa (39.9 ksi), worse than 91% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
20G properties
Typical room-temperature values for 20G-N; bars are the position among steel grades.
Physical3
20G 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 has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 91% of steel grades. Elongation at break is 28% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
20G 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 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 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's machinability is good (65/100, better than 93% of steel grades); weldability excellent (92/100); formability very good (82/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. 20G is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 20G
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.
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 |
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.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 20G in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- A515 Gr 60
How much does 20G cost?
20G is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
20G — frequently asked
What is 20G used for?
20G 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?
20G has a typical yield strength of 275 MPa (39.9 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 91% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 20G easy to machine?
Reasonably — machinability is rated good (65/100, better than 93% 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 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?
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 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?
20G 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.
How much does 20G cost?
20G is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.