Xi'an Dongmeng Group Co., Ltd. is one of the most reliable manufacturers and suppliers of carbon structural steel plate (a36, q235, s235, ss400) supplier & exporter in China, also supports customized service. With abundant experience, we warmly welcome you to wholesale cheap products in stock here and get free sample from our factory. For price consultation, contact us.
Carbon Steel Plate (S235JR, Q235, SS400, ASTM A36) is one of the most widely used low carbon structural steel materials in global engineering and construction industries. It offers excellent weldability, machinability, ductility, and strength consistency, making it ideal for building structures, machinery fabrication, bridges, shipbuilding, and heavy industrial applications.
As a professional steel manufacturer and exporter, we supply hot rolled carbon steel plates in compliance with international standards including ASTM A36, EN 10025 S235JR, JIS SS400, and GB Q235, ensuring stable chemical composition, mechanical performance, and reliable quality for global EPC projects.
With strict ISO-certified production systems, third-party inspection (SGS/BV), and EN10204 3.1/3.2 MTC certification, we provide not only steel materials but also engineering-grade reliability and supply chain assurance.
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High Quality
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Advanced Equipment
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Professional Team
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Custom Service
What is Carbon Structural Steel Plate?
Carbon structural steel plate is one of the most widely used materials in construction and engineering due to its excellent strength, weldability, and cost efficiency. Commonly supplied under standards such as ASTM A36 steel plate, S355 structural steel plate, and Q345 carbon steel plate, it is ideal for building structures, bridges, machinery fabrication, and industrial applications. With a balanced combination of mechanical performance and affordability, carbon structural steel plates are extensively used in structural steel fabrication, heavy equipment manufacturing, and infrastructure projects worldwide, making them a preferred choice for engineers and contractors seeking reliable and durable steel solutions.
Chemical Composition
The chemical composition of carbon structural steel plates varies depending on the grade, but typically includes the following elements:
| Element | Content (%) | Function |
|---|---|---|
| Carbon (C) | 0.05 – 0.30 | Increases strength and hardness |
| Manganese (Mn) | 0.30 – 1.50 | Improves strength and toughness |
| Silicon (Si) | ≤ 0.50 | Enhances deoxidation and strength |
| Phosphorus (P) | ≤ 0.04 | May increase brittleness if excessive |
| Sulfur (S) | ≤ 0.05 | Improves machinability but reduces ductility |
👉 Note: Lower carbon content improves weldability, while higher carbon increases strength but reduces ductility.
Mechanical Properties Comparison
| Grade | Yield Strength (MPa) | Tensile Strength (MPa) | Elongation (%) |
|---|---|---|---|
| ASTM A36 | ≥ 250 | 400 – 550 | ≥ 20 |
| S235 | ≥ 235 | 360 – 510 | ≥ 26 |
| S355 | ≥ 355 | 470 – 630 | ≥ 22 |
| Q345 | ≥ 345 | 470 – 630 | ≥ 20 |
A36 vs Q235 vs S235 vs SS400
| Standard | Grade | Equivalent Standards | Typical Yield Strength (MPa) | Description |
|---|---|---|---|---|
| ASTM (USA) | A36 | EN S235 / GB Q235 | ≥ 250 | General structural steel, excellent weldability |
| EN (Europe) | S235JR | ASTM A36 / GB Q235 | ≥ 235 | Basic structural applications |
| EN (Europe) | S275JR | ASTM A283 Gr.C | ≥ 275 | Medium strength structural steel |
| EN (Europe) | S355JR | ASTM A572 / GB Q345 | ≥ 355 | High strength structural steel |
| ASTM (USA) | A572 Gr.50 | EN S355 / GB Q345 | ≥ 345 | High-strength low-alloy structural steel |
| GB (China) | Q235B | ASTM A36 / EN S235 | ≥ 235 | Widely used construction steel |
| GB (China) | Q345B | ASTM A572 / EN S355 | ≥ 345 | High strength structural applications |
| JIS (Japan) | SS400 | ASTM A36 / EN S235 | ≥ 245 | General-purpose structural steel |
How to Choose Between A36, Q235, S235 and SS400
| Criteria | A36 (ASTM) | Q235 (GB) | S235 (EN) | SS400 (JIS) |
|---|---|---|---|---|
| Standard Region | USA / International | China | Europe | Japan / Asia |
| Yield Strength | ≥ 250 MPa | ≥ 235 MPa | ≥ 235 MPa | ≥ 245 MPa |
| Tensile Strength | 400–550 MPa | 370–500 MPa | 360–510 MPa | 400–510 MPa |
| Weldability | Excellent | Excellent | Excellent | Excellent |
| Availability | Global | Very common in China | Common in EU projects | Common in Asia |
| Certification | ASTM / ASME | GB/T | EN 10025 | JIS G3101 |
| Price Level | Medium | Low (most economical) | Medium | Medium |
| Typical Use | General construction, fabrication | Construction, structures, fabrication | Structural engineering, EU projects | Machinery, structures, fabrication |
Key Selection Logic
1. Based on Project Location
USA / Oil & Gas / International EPC → A36
China domestic projects → Q235
Europe / CE projects → S235
Japan / Southeast Asia → SS400
2. Based on Cost Sensitivity
Lowest cost → Q235
Balanced global option → A36 / S235
Regional supply advantage → SS400
3. Based on Performance
👉 These four grades are very similar in mechanical properties
Differences are mainly:
Standard system
Certification requirements
Slight strength variations
Specifications
| Category | Specification |
|---|---|
| Standard | ASTM A36, A283, A572 Gr.50 / EN 10025 (S235, S275, S355) / JIS G3101 (SS400) / GB/T 700 (Q235), GB/T 1591 (Q345) |
| Thickness | 3 – 200 mm (0.12" – 7.87") |
| Width | 1000 – 3500 mm (39.4" – 137.8") |
| Length | 2000 – 12000 mm (78.7" – 472.4") |
| Thickness Tolerance | EN 10029 Class A/B/C / ASTM A6 Standard |
| Surface Condition | Hot Rolled (HR), Pickled & Oiled (P&O), Shot Blasted, Painted/Coated |
| Edge Condition | Mill Edge (ME), Slit Edge (SE) |
| Delivery Condition | As Rolled (AR), Normalized (N), TMCP |
| Heat Treatment | Normalizing, Annealing, Stress Relieving |
| Inspection | Chemical Analysis, Mechanical Testing, UT Testing |
| Certification | EN 10204 3.1 / 3.2, Third-Party Inspection (SGS, BV, TUV) |
| Processing Services | Cutting, Bending, Welding, Drilling |
| Coating Options | Painting, Galvanizing, Anti-corrosion coating |
| Application | Construction, bridges, machinery, shipbuilding, infrastructure |
Applications
🏢 Construction steel structures
🌉 Bridges and infrastructure projects
🚢 Shipbuilding and marine structures
⚙️ Machinery manufacturing
🏭 Industrial equipment fabrication
🚧 Heavy engineering projects
🧱 Fabricated steel components
Resistant to wear and crack
Wear protection, scalable excellent chemical resistance, good alkali-resistance metal and acid energy
Improved Surface Quality:
Hot-rolled steel plates typically have smoother surfaces compared to cold-rolled steel plates, which are prone to surface defects such as unevenness. This is particularly important for applications requiring high surface quality, such as coatings or plating.
Superior Mechanical Properties
Hot-rolled steel plates are easier to form and process due to their surface not being as hard and strong as that of cold-rolled steel plates. This makes hot-rolled steel plates more widely used in manufacturing industries.
03.
Better Formability
Hot-rolled steel plates are easier to form and process due to their surface not being as hard and strong as that of cold-rolled steel plates. This makes hot-rolled steel plates more widely used in manufacturing industries.
15
years
We have been working in the industry since 2011
32
certificates
We have obtained most of the professional certificates in the industry and insist on international standards of production.
Production Process
Packing &Shipping
1.Standard sea-worthy export packing,
2.plastic cap with both ends
3.steel strip bundled package, waterproof cloth packaging
4.wooden case,wooden pallet package
5.container or bulk (According to customer's requirement)
6.wooden pallets with plastics protection.
7. 15-20MT can be loaded into 20 ftcontainer and 25-27MT can be loaded into 40 ft container.
8. For 20 ft container the max length is 5.8m, for 40 ft container the max length is 11.8m.
9. The other packing can be made based on the customer requirement.
Why Choose Us
Factory-direct supply with competitive pricing
Stable stock for fast delivery
Custom cutting & processing service
International export experience (Europe, Middle East, Southeast Asia)
Strict quality control system
Engineering technical support available
Product Delivery Standards
Standard export seaworthy packaging
Steel plates bundled with steel strips
Waterproof protection and anti-rust oil
Custom marking available
MTC provided (EN10204 3.1 / 3.2)
Contact Us
Phone / WhatsApp / WeChat: +8615769214734
Email: office@dongmjd.com
FAQ
1. Are A36, Q235, S235, and SS400 equivalent?
Yes, they are generally considered equivalent grades for structural applications. However, they are produced under different standards (ASTM, GB, EN, JIS), and slight differences may exist in chemical composition, mechanical properties, and certification requirements.
2. Which grade is the strongest among A36, Q235, S235, and SS400?
All four grades have similar strength levels, but:
A36 typically has slightly higher yield strength (~250 MPa)
Q235 and S235 are around 235 MPa
SS400 is around 245 MPa
👉 In practice, the difference is small and not critical for most applications.
3. Which steel grade is the most cost-effective?
Q235 is usually the most economical option, especially for projects sourced from China.
However, total cost depends on logistics, certification, and project location.
4. Can these grades be used interchangeably?
In many general structural applications, yes.
But always confirm:
Project specifications
Required standards (ASTM, EN, etc.)
Engineering approvals
👉 Substitution without approval is not recommended for critical structures.
5. Which grade should I choose for export projects?
USA / international projects → A36
Europe → S235
China → Q235
Japan / Asia → SS400
👉 Choose based on client requirements and compliance standards.
6. What are the main differences between these grades?
The main differences are:
Standard system (ASTM / GB / EN / JIS)
Certification requirements
Slight variations in mechanical properties
👉 Performance is largely comparable.
7. Which grade has the best weldability?
All four grades offer excellent weldability, making them suitable for:
Structural fabrication
Welding construction
Machinery manufacturing
8. Are these steels suitable for outdoor or corrosive environments?
They have limited corrosion resistance.
For outdoor or harsh environments, additional protection is required:
Painting
Galvanizing
Anti-corrosion coating
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