Z-Direction Steel Plate (Lamellar Tearing Resistant Steel)
Z Direction Steel Plate, also known as Lamellar Tearing Resistant Steel, is a specialized structural steel designed to resist tearing in the thickness direction (Z-axis). During heavy welding of thick plates, shrinkage stresses can cause delamination.
Our Z-direction steels (Z15, Z25, Z35) are specially designed to eliminate this risk. By employing the LF+VD vacuum refining process and strictly controlling the sulfur content (≤0.005%), the steel plates we offer have high ductility in the thickness direction, thus ensuring the safety and durability of your structure.
Z Direction Steel Plate Technical Specifications & Grades
We supply Z-direction steel in full compliance with international standards, including ASTM A770, EN 10164, and GB/T 5313.
| Quality Class | Reduction of Area (Zz %) | Sulfur (S) Content | Typical Applications |
| Z15 | ≥ 15% | ≤ 0.010% | General structural steel components |
| Z25 | ≥ 25% | ≤ 0.007% | High-rise buildings & heavy machinery |
| Z35 | ≥ 35% | ≤ 0.005% | Offshore platforms & critical bridge joints |
Featured Material Combinations
Z-direction performance is an additional requirement added to standard structural grades. We offer the following high-performance combinations:
1. Low Alloy High Strength (HSLA) Series
ASTM Grades: A572 Gr.50-Z25/Z35, A588 (Weathering Steel)-Z35
EN 10025 Grades: S355JR+Z25, S355J2+Z35, S355K2+Z35
GB/T Grades: Q355B/C/D/E-Z15/Z25/Z35
2. Shipbuilding & Offshore Grades
ABS/DNV/LR Standards: EH36-Z35, EQ56-Z35, EH40-Z35 (High-strength plates for marine environments).
3. High-Rise Construction Steel
Q345GJ / Q390GJ Series: Specialized for seismic resistance in skyscraper “Honeybee” nodes.
International Standards Comparison for Z-Direction Steel
When sourcing Z-direction steel for international projects, standard compliance is the most critical factor. Our products can be manufactured and tested to meet or exceed the following global benchmarks:
| Region / Standard | Standard Number | Quality Grades / Classes | Key Requirement (Zz %) |
| International (ISO) | ISO 24234 | Z15, Z25, Z35 | ≥ 15%, 25%, 35% |
| Europe (EN) | EN 10164 | Z15, Z25, Z35 | ≥ 15%, 25%, 35% |
| USA (ASTM) | ASTM A770 | – | 20%, 25%, 35% (Customizable) |
| China (GB) | GB/T 5313 | Z15, Z25, Z35 | ≥ 15%, 25%, 35% |
| Japan (JIS) | JIS G3199 | Z15, Z25, Z35 | ≥ 15%, 25%, 35% |
| Australia (AS) | AS/NZS 3678 | Optional Z-Testing | Compliant with Appendix C |
Important Note for Engineers: While EN 10164 and GB/T 5313 are numerically identical in their Zz requirements, ASTM A770 (USA) often requires specific reduction of area percentages that may vary by project. We provide customized testing to ensure 100% compliance with your specific Job Specifications.
Why Choose Our Z Direction Steel Plate?
Ultra-Low Sulfur Metallurgy: Produced via LF (Ladle Furnace) + VD (Vacuum Degassing) routes to ensure extreme purity.
100% Ultrasonic Testing (UT): Every plate is tested to ASTM A578 Level C or EN 10160 S2/E2 standards to guarantee internal soundness.
Third-Party Certification: Material Test Reports (MTRs) provided with 3.1/3.2 certification. We welcome inspections by SGS, BV, or ABS.
Custom Dimensions: Thickness range from 16mm to 250mm (0.63″ to 10“) with precision CNC oxy-fuel cutting services.
Looking Forward to Becoming One of Your Z Direction Steel Plate Suppliers
Engineering Applications of Z Direction Steel Plate
Offshore Engineering: Jack-up rig legs and offshore platform nodes.
Infrastructure: Suspension bridge towers and large-span stadium trusses.
Energy: Wind turbine towers and heavy pressure vessel supports.
If you are unsure whether your project requires Z direction steel plates, you can contact us directly. We will arrange for an engineer to assess your project and find the appropriate steel grade.
FAQ for Z Direction Steel Plate Buyers
Can I request Z-direction testing for any steel grade?
Generally, yes. It is most commonly applied to plates thicker than 40mm where welding stresses are high.
What is the lead time for Z-direction customized orders?
Standard stock is available for immediate shipment. Custom mill production typically takes 30–45 days depending on the grade.
What is the primary difference between Z15, Z25, and Z35?
The numbers represent the minimum average Reduction of Area (Zz) percentage during a through-thickness tensile test.
Z15: Suitable for standard structural joints with moderate welding stress.
Z25: The industry standard for heavy-duty construction and bridges.
Z35: The highest level, mandatory for critical, high-load nodes in offshore platforms and skyscrapers to ensure zero risk of lamellar tearing.
Does Z-direction steel come with Ultrasonic Testing (UT) by default?
Yes. Because Z-direction performance depends on internal purity, all our Z-plates undergo mandatory Ultrasonic Testing. We typically follow ASTM A578 Level C or EN 10160 S2/E2, but we can provide higher sensitivity testing (Level S3/E3) upon request for nuclear or aerospace applications.
Can I order Z-direction performance on any steel grade (e.g., S355 or A572)?
Absolutely. Z-direction is a “supplementary requirement.” You can add it to most structural steel grades. Common combinations for export include S355J2+Z35, ASTM A572 Gr.50-Z25, and Q355D-Z35. If you have a specific project grade, our technical team can confirm compatibility.
How do you guarantee the quality for international shipments?
Every plate is issued an Original Mill Test Certificate (MTR) according to EN 10204 3.1. For high-stakes projects, we support EN 10204 3.2 certification, where a third-party inspector (SGS, ABS, BV, or Lloyd’s Register) witnesses the Z-direction tensile test and chemical analysis at our facility.
Why is the sulfur (S) content so low in Z-direction steel?
Sulfur forms manganese sulfide inclusions, which are flattened into “flakes” during rolling. These flakes form a weak inner layer. By reducing the sulfur content to ≤0.005% (using the LF+VD refining process), we can eliminate these layers, thus allowing the steel to maintain good ductility in all three directions.
Do you provide CNC cutting and edge preparation?
Yes. We offer full processing services including:
Precision CNC Flame/Plasma Cutting to your drawings.
Beveling (K, V, Y, U types) to prepare for immediate welding upon arrival at your site.
Sandblasting and Priming to prevent rust during sea freight.
Get Z Direction Steel Plate Prices From Huaxiao Metal Supplier
Ready to ensure the structural integrity of your project?
Choosing the wrong Z Direction Steel Plate Grade can lead to costly delays or even catastrophic structural failure. Don’t leave your project to chance. Choose a supplier who understands the stringent technical requirements of Z-direction performance.
Why submit an inquiry to us today?
Expert Technical Support: Unsure whether you need Z15, Z25, or Z35? Our engineers will review your shop drawings and provide cost-effective material recommendations within 24 hours.
Risk-Free Quality Guarantee: We provide a pre-shipment MTR (Made in Taiwan) report and support 100% third-party inspection (SGS/BV). If Z-direction performance does not meet standards, we will replace the entire batch free of charge.
Global Logistics Expertise: Whether it’s DDP to your warehouse or CIF to your nearest port, we handle complex documentation and ocean-ready packaging to ensure your steel plates are rust-free and ready for welding.
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