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Q355C STRUCTURAL STEEL PLATE

Chemical element composition – hot-rolled Q355C low-alloy high-strength steel 🔍 Q355C Grade Lookup →

Product Overview

Q355C is a Chinese grade low-alloy high-strength structural steel conforming to GB/T 1591-2018 standard. Grade C provides guaranteed impact toughness at 0°C. With minimum yield strength of 355MPa (≤16mm), it is widely used in bridges, buildings, vehicles, pressure vessels, and engineering structures requiring enhanced low-temperature performance.

Equivalent grades: Q355C ↔ Q345C (previous Chinese standard), Q390C (higher strength domestic), S355J0 (EN 10025-2), S355C (ISO 630-2), ASTM A572 Gr.50 (USA).

International Grade Comparison

Europe (EN 10025-2)

S355J0

Impact: 0°C (27J)

Yield: 355MPa

C: ≤0.24%

Si: ≤0.55%

Mn: ≤1.60%

P: ≤0.035%

S: ≤0.035%

Nb: ≤0.05%

V: ≤0.12%

Ti: ≤0.05%

ISO 630-2

S355C

Impact: 0°C (27J)

Yield: 355MPa

C: ≤0.22%

Si: ≤0.55%

Mn: ≤1.60%

P: ≤0.035%

S: ≤0.035%

Nb: ≤0.05%

V: ≤0.12%

Ti: ≤0.05%

USA (ASTM A572)

Gr.50

Impact: Not specified

Yield: 345MPa

C: ≤0.23%

Si: ≤0.40%

Mn: ≤1.35%

P: ≤0.025%

S: ≤0.025%

Nb: ≤0.05%

V: ≤0.15%

Ti: ≤0.05%

China (GB/T 1591)

Q390C

Impact: 0°C (34J)

Yield: 390MPa

C: ≤0.20%

Si: ≤0.50%

Mn: 1.00-1.70%

P: ≤0.030%

S: ≤0.030%

Nb: ≤0.05%

V: ≤0.12%

Ti: ≤0.05%

China (GB/T 1591)

Q345C

Impact: 0°C (34J)

Yield: 345MPa

C: ≤0.20%

Si: ≤0.50%

Mn: 1.00-1.60%

P: ≤0.030%

S: ≤0.030%

Nb: ≤0.07%

V: ≤0.15%

Ti: ≤0.20%

Note: Q355C offers 0°C impact toughness comparable to S355J0 and S355C, with higher strength option Q390C available; always verify specific requirements before substitution.

China Grade Comparison: Q355B vs Q355C vs Q355D

Q355B

Grade B

Impact: 20°C

KV2 (L): 34J

C: ≤0.20%

P: ≤0.035%

S: ≤0.035%

Q355C

Grade C

Impact: 0°C

KV2 (L): 34J

C: ≤0.20%

P: ≤0.030%

S: ≤0.030%

Q355D

Grade D

Impact: -20°C

KV2 (L): 40J

C: ≤0.20%

P: ≤0.030%

S: ≤0.025%

Note: Q355 series grades share identical tensile properties (yield strength, tensile strength, elongation). The key differences are impact test temperature and corresponding impurity limits: B (20°C, 34J), C (0°C, 34J), D (-20°C, 40J), with progressively tighter P/S control for lower temperatures.

Key Advantages

Excellent Weldability

Low carbon content (≤0.20-0.22%) and low carbon equivalent ensure superior weldability without preheating for most thicknesses.

High Strength

Minimum yield strength of 355MPa (≤16mm) and tensile strength 470-630MPa, ideal for structural applications.

0°C Impact Toughness

Guaranteed impact energy of 34J at 0°C (longitudinal), suitable for moderate low-temperature service conditions.

Applications

Building Structures

High-rise buildings, industrial plants

Heavy Machinery

Construction machinery, crane booms

Q355C Chemical Composition (GB/T 1591-2018)

Grade C (≤40mm) C (>40mm) Si Mn P S Cr Ni Cu N
Q355C ≤0.20 ≤0.22 ≤0.55 ≤1.6 ≤0.030 ≤0.030 ≤0.3 ≤0.3 ≤0.4 ≤0.012

Notes: Carbon content ≤0.20% for thickness ≤40mm, ≤0.22% for thickness >40mm per GB/T 1591-2018. Micro-alloying elements (Nb, V, Ti) may be added singly or in combination. V+Nb+Ti ≤0.22%.

Q355C Mechanical 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
Q355C 355 345 335 325 315 295 285 275

Tensile Strength Rm (MPa)

Grade ≤100mm >100-150mm >150-250mm
Q355C 470-630 450-600 450-600*

* For thickness >150-250mm, tensile strength 450-600 MPa applies only to quality grade D plates.

Percentage Elongation After Fracture A% (min.)

Thickness (mm) Longitudinal Transverse
≤40 22 20
>40-63 21 19
>63-100 20 18
>100-150 18 18
>150-250 17 17
>250-400* 17 17

Notes: Per GB/T 1591-2018 Table 8. * For thickness >250-400mm, applies only to quality grade D plates. Longitudinal specimens for plates ≥600mm width.

Impact Energy KV2 at 0°C (J) min.

Grade Longitudinal Transverse
Q355C 34 27

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

Size & Specification

Product Form Thickness (mm) Width (mm) Length (mm)
Plate 3 - 300 1000 - 4000 3000 - 18000
Sheet / Coil 1.5 - 20 900 - 2000 Coil or cut to length

Other sizes available. Tolerances per GB/T 709.

Quality & Manufacturing Assurance

Modern Production

Advanced continuous casting and controlled rolling

In-process Inspection

Spectral analysis, mechanical testing, 0°C impact

Full Documentation

Mill Test Certificate EN 10204 3.1

Packaging & Logistics

  • Packaging: Steel plates bundled with steel straps on wooden skids. Coils wrapped with waterproof paper.
  • Marking: Each bundle 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

Carbon content? ≤0.20% for ≤40mm and ≤0.22% for >40mm thickness.
Weldability? Excellent weldability due to low carbon equivalent (Ceq ≤0.45).
Thickness range? Available from 3mm to 300mm in standard plate form.
Q355B vs Q355C? Q355C provides 0°C impact toughness while Q355B offers 20°C impact.
Mill certificates? Yes, EN 10204 Type 3.1 or 3.2 available upon request.
MOQ? 5 tons for stock sizes, negotiable for mill production orders.