Q420NC STRUCTURAL STEEL
Product Overview
Q420NC is a Chinese grade low-alloy high-strength structural steel conforming to GB/T 1591-2018 standard. It features a normalized or normalized plus tempered delivery condition, offering improved toughness and consistent properties. Grade C provides guaranteed impact toughness at 0°C. With minimum yield strength of 420MPa, it provides higher strength than Q355 and Q390 series and is widely used in bridges, buildings, pressure vessels, and engineering structures requiring enhanced load-bearing capacity in cold environments.
International Grade Comparison
Europe (EN 10025-3)
S420N
Impact: -20°C (40J)
Yield: 420MPa
C: ≤0.20%
Si: ≤0.60%
Mn: 1.00-1.70%
P: ≤0.025%
S: ≤0.020%
Nb: ≤0.05%
V: ≤0.12%
Ti: ≤0.05%
China (GB/T 1591)
Q420NC
Impact: 0°C (34J)
Yield: 420MPa
C: ≤0.20%
Si: ≤0.60%
Mn: 1.00-1.70%
P: ≤0.030%
S: ≤0.030%
Nb: 0.01-0.05%
V: 0.01-0.20%
Ti: 0.006-0.05%
Delivery: Normalized / N+T
USA (ASTM A572)
Gr.60
Impact: Not specified
Yield: 415MPa
C: ≤0.26%
Si: ≤0.40%
Mn: ≤1.35%
P: ≤0.025%
S: ≤0.025%
Nb: ≤0.05%
V: ≤0.15%
Ti: ≤0.05%
China Grade Comparison: Q420C vs Q420NC
Q420C
Yield: 420MPa
Impact 0°C: 34J
P: ≤0.030%
S: ≤0.030%
Delivery: As-rolled or normalized
Q420NC
Yield: 420MPa
Impact 0°C: 34J
P: ≤0.030%
S: ≤0.030%
Delivery: Normalized (guaranteed grain refinement)
Key Advantages
Higher Strength
Min yield 420MPa (≤16mm), tensile 520-680MPa.
Normalized Condition
Delivered normalized/N+T for refined grain structure.
0°C Impact Toughness
Grade C provides guaranteed impact energy of 34J at 0°C (longitudinal).
Applications
Building Structures
High-rise buildings, stadiums, industrial facilities in cold regions.
Heavy Machinery
Crane booms, mining equipment, bridge components for cold service.
Shipbuilding
Hull structures, offshore platforms requiring low-temperature toughness.
Q420NC Chemical Composition (GB/T 1591-2018)
Chemical element composition of Chinese grade Q420NC low alloy high strength structural steel
Q420NC Approximate Grade Lookup Table
| Grade | Chemical Composition（Quality Fraction）/ % | |||||||||||||||||||||||||||||||
| Steel grade | Quality grade | C | Si | Mn | Pᵃ | Sᵃ | Nb | V | Tiᶜ | Cr | Ni | Cu | Mo | N | Alsᵈ≥ | |||||||||||||||||
| ≤ | ≤ | ≤ | ||||||||||||||||||||||||||||||
| Q420N | C | 0.2 | 0.6 | 1~1.7 | 0.03 | 0.03 | 0.01~0.05 | 0.01~0.2 | 0.006~0.05 | 0.3 | 0.8 | 0.4 | 0.1 | 0.015 | 0.015 | |||||||||||||||||
Notes:
a. For structural steel and bar stock, the upper limit for phosphorus and sulfur content can be increased by 0.005%.
b. V+Nb+Ti≤0.22%, Mo+Cr≤0.30%.
c. Ti can be as high as 0.20%.
d. All-aluminum (Alt) can be used as a substitute, in which case the minimum content of all-aluminum is 0.020%. When grain-refining elements such as niobium, vanadium, and titanium are added to the steel and their content is not less than the lower limit specified in the table, there is no limit to the lower limit of aluminum content.
e. The steel should contain at least one of the grain-refining elements such as aluminum, niobium, vanadium, and titanium. When added alone or in combination, the content of at least one alloying element should not be less than the lower limit specified in the table.
Q420NC Tensile Properties (GB/T 1591-2018)
| Upper yield strength ReH/MPa ≥ | |||||||||
| Grade | ≤16mm | 16-40mm | 40-63mm | 63-80mm | 80-100mm | 100-150mm | 150-200mm | 200-250mm | |
| Q420NC | 420 | 400 | 390 | 370 | 360 | 340 | 330 | 320 | |
| Property | Thickness Range | Value |
| Tensile Strength Rm | ≤100mm | 520-680 MPa |
| 100-200mm | 500-650 MPa | |
| 200-250mm | 500-650 MPa | |
| Elongation A % | ≤16mm | 19% |
| 16-40mm | 19% | |
| 40-63mm | 19% | |
| 63-80mm | 18% | |
| 80-200mm | 18% | |
| 200-250mm | 18% |
| Impact Temperature | 0°C | |
| KV2 (J) ≥ | Longitudinal | 34 |
| Transverse | 27 | |
Notes: Normalized condition includes normalized and tempered condition. When yield not obvious, use Rp0.2.
Size & Specification
| Product Form | Thickness (mm) | Width (mm) | Length (mm) |
| Plate | 3 - 250 | 1000 - 4000 | 3000 - 18000 |
| Sheet / Coil | 1.5 - 20 | 900 - 2000 | Coil or cut to length |
Other sizes available upon request. Custom cutting available.
Customizable Options
We offer comprehensive customization services to meet your specific project requirements:
| Custom Dimensions Non-standard sizes, laser cutting |
Surface Treatments Shot blasting, priming |
Edge Preparation Beveling, machining |
| Custom Heat Treatment Normalizing, stress relieving |
Special Testing Third-party inspection |
Custom Marking Special labeling |
Quality & Manufacturing Assurance
Modern Production
Normalized heat treatment for grain refinement.
In-process Inspection
Spectral analysis & 0°C impact testing.
MTC 3.1/3.2
Full documentation & traceability.
Packaging & Logistics
- Packaging: Bundled plates with steel straps on wooden skids / coils wrapped waterproof.
- Marking: Each bundle/coil marked with grade, size, heat number, weight.
- Logistics: FOB, CIF, CFR from main Chinese ports. Lead time 25-35 days.
Request a Quote
Emails go directly to customize@cehesteel.com — reply within 2h.
Frequently Asked Questions
Q420NC is a normalized low-alloy high-strength steel per GB/T 1591-2018, with minimum yield strength 420MPa and guaranteed impact toughness of 34J at 0°C (longitudinal).
Q420NC is comparable to Q420C (domestic), EN 10025 S420N (Europe), and ASTM A572 Grade 60 (USA).
Same chemical composition. NC is normalized with guaranteed grain refinement, C can be as-rolled or normalized.
Nb 0.01-0.05%, V 0.01-0.20%, Ti 0.006-0.05%, Als ≥0.015%.
Excellent with low CE and fine grain normalized structure.
3mm to 250mm plates, 1.5-20mm coils/sheets with custom cutting available.