Q420B Z15 Z25 Z35 Steel Plate Supplier | High-Strength Z-Direction Steel – Huaxiao Metal
Looking for Q420B Z15, Z25, Z35 steel plates with high strength and excellent resistance to lamellar tearing?
Huaxiao Metal is a professional Z-direction steel plate supplier, offering Q420B high-strength structural steel plates designed for critical welding applications such as bridges, offshore engineering, and heavy equipment manufacturing.
Q420B Z-direction steel plate is a high-strength low-alloy (HSLA) structural steel specifically designed to resist lamellar tearing in thick section applications. By controlling the sulfur content and implementing advanced calcium treatment, Huaxiao Metal provides Q420B plates with superior through-thickness ductility, categorized into Z15, Z25, and Z35 grades based on the reduction of area (RA%) during tensile testing.
Available Specifications
Thickness: 8mm – 200mm
Width: 1500mm – 4000mm
Length: 3000mm – 12000mm
Delivery Condition: Hot Rolled / Normalized / TMCP
Surface: Black / Shot Blasted / Coated
Testing: UT (Ultrasonic Testing) available
👉 Custom cutting, drilling, and machining services supported
What Is Q420B Z15/Z25/Z35 Steel Plate?
Q420B steel plate is a high-strength low-alloy structural steel under GB/T 1591 standard, with a minimum yield strength of 420 MPa.
The Z15, Z25, Z35 grades refer to through-thickness (Z-direction) performance, which measures the steel’s resistance to lamellar tearing during welding.
📊 Z-Direction Performance Comparison
| Grade | Reduction of Area (Z-direction) | Performance Level | Recommended Use |
|---|---|---|---|
| Z15 | ≥15% | Basic | General structures |
| Z25 | ≥25% | Medium | Bridges / machinery |
| Z35 | ≥35% | High | Heavy welding / offshore |
👉 Not sure which Z grade fits your project? Contact Huaxiao Metal for expert advice.
⚙️ Chemical Composition of Q420B Steel
| Element | Content (%) |
|---|---|
| C | ≤0.20 |
| Si | ≤0.50 |
| Mn | 1.00–1.70 |
| P | ≤0.035 |
| S | ≤0.035 |
✔ Designed for strength + weldability balance
Technical Specifications
| Property | Q420B Z15 | Q420B Z25 | Q420B Z35 |
| Yield Strength (ReH) | ≥ 420 MPa | ≥ 420 MPa | ≥ 420 MPa |
| Tensile Strength (Rm) | 520 – 680 MPa | 520 – 680 MPa | 520 – 680 MPa |
| Z-Direction RA (Min Avg) | 15% | 25% | 35% |
| Standard | GB/T 1591, GB/T 5313 | GB/T 1591, GB/T 5313 | GB/T 1591, GB/T 5313 |
👉 Suitable for heavy-load and low-temperature environments
Key Advantages of Q420B Z-Direction Steel Plate
1. Excellent Lamellar Tearing Resistance
Z15 / Z25 / Z35 grades ensure structural safety in thick welded plates.
2. Higher Strength Than Q390B
Q420B provides stronger load-bearing capacity, ideal for heavy-duty structures.
3. Outstanding Weldability
Controlled sulfur content reduces internal cracking risk.
4. Suitable for Critical Engineering Projects
Widely used where weld reliability is essential
👉 Upgrade your project safety with certified Z-direction steel plates
Applications of Q420B Z15 Z25 Z35 Steel Plates
Q420B Z-direction steel is the preferred material for complex stress environments:
- Bridge construction
- Offshore oil & gas platforms
- Heavy machinery manufacturing
- Pressure vessels
- Steel structure buildings
- Wind power towers
👉 Best choice for high-stress welded structures
Q420B Z Steel vs Normal Steel Plate
| Feature | Z-Direction Steel | Normal Steel |
|---|---|---|
| Lamellar tearing resistance | ✅ High | ❌ Low |
| Weld safety | ✅ Reliable | ⚠ Risk |
| Thickness suitability | Thick plates | Limited |
| Application | Critical structures | General |
👉 Using non-Z steel in thick welding = potential failure risk
Q420B vs Q390B Steel Plate
| Feature | Q420B | Q390B |
|---|---|---|
| Yield Strength | 420 MPa | 390 MPa |
| Load Capacity | Higher | Medium |
| Application | Heavy structures | General heavy |
| Cost | Slightly higher | Lower |
👉 Q420B is ideal for projects requiring higher strength
Packaging & Export (Very Important for Buyers)
- Waterproof packaging + steel strapping
- Wooden pallet or bulk shipment
- Anti-rust protection
- Custom export packaging available
🌍 Exported to:
Europe / Middle East / Southeast Asia / South America
👉 Safe delivery guaranteed for long-distance shipping
Procurement Considerations for Q420B Steel Plate
Before purchasing Q420B Z-direction steel plates, buyers should confirm:
- ✔ Required Z-grade (Z15/Z25/Z35)
- ✔ Plate thickness (critical for lamellar tearing risk)
- ✔ Welding method and stress level
- ✔ Need for UT testing
- ✔ Surface treatment & delivery condition
👉 Avoid project risks by confirming specifications before ordering
👉 Contact Huaxiao Metal for technical support and pricing
Why Choose Huaxiao Metal?
✅ 15+ years steel export experience
✅ Stable inventory & fast delivery
✅ Competitive factory pricing
✅ Full MTC + third-party inspection (SGS / BV)
✅ One-stop steel supply solution
👉 Trusted by global engineering companies
We have supplied Z-direction steel plates to Europe, the Middle East, Southeast Asia, and South America
Work with a trusted steel supplier – send your inquiry today
FAQ – Q420B Z15 Z25 Z35 Steel Plate
Does Q420B Z-direction steel require special welding?
Yes, while Q420B has good weldability, Z-direction plates are often used in thick sections. Preheating and using low-hydrogen electrodes are recommended to further minimize the risk of cold cracking.
When should I choose Z35?
For thick plates (>40mm) with heavy welding stress, Z35 is strongly recommended.
Do you provide UT tested plates?
Yes, we offer 100% UT tested plates with international standards.
Can you customize sizes?
Yes, we support cutting, drilling, and machining services.
Can you provide UT tested plates?
Yes, we offer 100% UT tested plates according to EN or Chinese standards.
Flexible MOQ depending on stock and specifications.
Flexible MOQ depending on stock and specification.
Get a Quote for Q420B Z-Direction Steel Plate
Looking for a reliable Q420B Z15 Z25 Z35 steel plate supplier?
👉 Contact Huaxiao Metal now to get:
- Best factory price
- Fast delivery
- Professional technical support
