Author: wp2647218172

Recently, Tianjin Yuantai Delun Steel Pipe Manufacturing Group Co., Ltd. has realized a major technological breakthrough in the field of straight out square pipes in the unit! The wall thickness limit of square pipe specification 50mm50mm is raised to 7.75mm, far exceeding the previous industry norm of 5.75mm, which refreshes the new height of the Group’s production technology.

(50mm50mm7.75mm)

This breakthrough stems from the Group’s R&D and production teams’ dedication to craftsmanship and continuous optimization of equipments, which have successfully overcome key technical problems such as thick-walled steel pipe molding, welding stability, etc., and provided better quality solutions for high-end application scenarios.

(50mm50mm7.75mm)

The breakthrough square tube product 50mm50mm*7.75mm is specially designed for curtain wall aluminum profile insertion scenarios, and with its ultra-thick wall thickness, high-precision dimensions, and excellent mechanical properties, it perfectly matches the stringent requirements of the curtain wall structure in terms of load-bearing capacity, wind pressure resistance, and corrosion resistance. According to customer feedback, Yuantai Delun’s products not only enhance the overall safety of the curtain wall, but also shorten the delivery cycle and reduce the overall cost through efficient production.
In the future, Yuantai Derun will continue to take technological innovation as the core, plowing into niche areas, providing higher quality and more competitive steel pipe products for the construction, industrial and other fields, and helping our partners to win the first opportunity in the market!
Tianjin Yuantai Derun Group is looking forward to sincere cooperation with you, mutual benefit, welcome to visit our factory.

Tangshan Yuantai Derun Steel Pipe Co., Ltd., a subsidiary of Yuantai Derun Group, has successfully launched its Zinc-Aluminum-Magnesium (ZAM) series products into mass production. Since the announcement, these innovative offerings have garnered enthusiastic attention from customers across the industry.

The current ZAM-coated steel strip production capabilities span widths from 550mm to 1010mm. Our expanded product portfolio now includes ZAM square tubes and solar mounting brackets, complemented by newly added hot-dip galvanized round pipes (ranging from 4″ to 8″ in diameter) and rectangular/square tubes (from 30x30mm to 150x150mm specifications).

Join us as we take a virtual tour through the advanced facilities of Tangshan Yuantai Derun Steel Pipe Co., Ltd., where cutting-edge technology meets sustainable manufacturing solutions.

Office Building Rendering

Aerial view of the factory

Steel coil pickling equipment

The pickling line successfully rolled out its inaugural finished coil at 9:20 AM on April 25, 2023.

Cold rolling equipment

Steel coil cutting equipment

Yuantai Derun: Innovating Solar Solutions with ZAM Square & Rectangular Tubes
With over two decades of specialization in square and rectangular tubing, our new Zinc-Aluminum-Magnesium (ZAM) series delivers groundbreaking advancements. Compared to traditional hot-dip galvanized counterparts, ZAM square/rectangular tubes demonstrate superior corrosion resistance and self-healing properties, significantly extending support structure service life – particularly advantageous for solar mounting systems.

Key Benefits for Photovoltaic Applications:

1. Cost Efficiency
   ZAM-coated materials undergo continuous galvanizing pretreatment on hot-rolled substrates, enabling direct engineering implementation post-forming. This innovation:
   • Reduces component processing timelines
   • Enhances project schedule control
   • Eliminates hot-dip post-treatment requirements
   • Minimizes management overhead and labor costs

2. Environmental Sustainability
By eliminating the hot-dip galvanizing process, ZAM products significantly reduce industrial pollution associated with traditional zinc coating methods, aligning with national green manufacturing initiatives and contributing to eco-friendly industrial practices.

3. Self-Healing Protection
ZAM materials exhibit unique corrosion resistance through autonomous repair mechanisms. When scratched or cut, the coating forms a dense protective film composed of zinc hydroxide, alkaline zinc chloride, and magnesium hydroxide. This barrier effectively isolates exposed metal substrates from corrosive elements, preventing further oxidation and ensuring long-term structural integrity.

4. Standardization & Industry Recognition
With stable material properties and precise dimensional control, ZAM tubing enables standardized photovoltaic bracket production at scale. Recognized by leading energy providers, ZAM-coated products deliver:

•Superior surface quality for seamless integration

•Unmatched corrosion resistance exceeding industry standards

•Cost-effective sustainability through reduced lifecycle maintenance

•Proven ROI across utility-scale solar installations

The following is the zinc-aluminum-magnesium pipe making equipment show

Let’s visit the hot-dip galvanizing production plant in the new Tangshan plant.

Tianjin Yuantai Derun Group operates 51 high-frequency welded black pipe production lines capable of manufacturing over 600 standard specifications. Additionally, we utilize 4 specialized shape-reforming units to produce rare market-available profiles, including ultra-large diameter and extra-thick-walled square/rectangular tubes, right-angle tubes, octagonal tubes, and trapezoidal tubes. We also offer third-party tempering and annealing services. Supported by our expert technical team and advanced equipment, our next strategic objective is to pioneer the development of direct-formed specialty tubing solutions.

I. Production Specifications & Compliance Standards
Shaped Redrawing Tubes:

Square Tubes: 80×80mm to 1200×1200mm

Rectangular Tubes: 50×100mm to 1200×1500mm

Wall Thickness: 2.75mm–50mm

Standard: GB/T 3091-2015 (Structural Steel Tubes for Fluid Transportation)

Customizable Materials: Q235, Q355, Q390, Q420, Q460, high-strength steel, weather-resistant steel, and other alloys.

Innovative Hot-Rolled Right-Angle Tube Technology:
Our advanced manufacturing process combines:

In-line hot rolling of 4 corners

Full-profile heating
This dual approach achieves energy-efficient operations and high-throughput production.

Depicted: 300mm×300mm×14mm Right-Angle Tube

Depicted: 150mm×400mm×25mm Right-Angle Tube

Depicted: 120mm×400mm×20mm Right-Angle Tube

Depicted: 80mm×240mm×20mm Right-Angle Tube

II. Production Process Flow

Raw Material Inspection – Round pipe verification

Loading – Automated feeding system

Hydraulic Pushing – Precision alignment

Roll Forming Extrusion – Circular-to-square transformation

Geometric Inspection – Dimensional accuracy, flatness, perpendicularity, radius (R-angle)

Unloading & Straightness Check – Torsion/twist detection

Port-End Calibration – Eliminating deformation zones from forming process

Saw Cutting & Edge Trimming – Precision length control

Final Marking & Quality Certification – Laser spray labeling

Warehousing – Systematic inventory management

III. Advanced Processing Capabilities
Tianjin Yuantai Derun Group’s newly commissioned intelligent tempering furnace addresses critical stress relief requirements through:

Artificial Aging Techniques

1. Thermal Stress Relief
Heating steel tubes to 550-650°C for stress relief annealing offers:

Time efficiency: 80-90% faster than natural aging

Comprehensive stress elimination: Up to 98% residual stress reduction

Microstructural optimization: Enhanced grain boundary alignment

2. Vibratory Stress Relief (VSR)
Our advanced vibration aging system operates through:
① Resonance activation: Matching workpiece’s natural frequency (20-200Hz range)
② Energy superposition: Combining alternating stresses (5-50MPa) with residual stresses
③ Energy dissipation: Molecular friction absorption at critical thresholds (0.1-0.3% strain)
④ Stress homogenization: Achieving 70-85% stress reduction through viscoelastic-plastic deformation

Post-Treatment Performance Enhancement
S&R tubes processed with these methods demonstrate:
✓ 15-25% improvement in yield strength (Q355: ≥355MPa → 410MPa)
✓ 10-18% increase in tensile strength (510-680MPa range)
✓ 5-8% enhanced elongation at break (δ₅ ≥24%)
✓ 30% higher impact compressive resistance (KU₂ ≥60J at -20°C)

This synergistic engineering approach creates performance characteristics exceeding conventional arithmetic summation – a true industrial “1+1>2” effect..

Depicted: 500×500×40mm Redrawn Tube Post Stress Relief Annealing

Depicted: Twist/Torsion Testing of Redrawn Tube Post Stress Relief Annealing

IV. Engineering Milestones

1.OCT Shenzhen 128m Ferris Wheel:
The primary support columns of this landmark structure incorporate Yuantai Derun’s proprietary beveled octagonal tubes, engineered to withstand extreme torsional loads while maintaining architectural precision.

2. Google Singapore Headquarters
The structural framework utilizes Yuantai Derun’s 500×500×36mm reshaped tubes manufactured from S355J2H steel (EN 10210-compliant), with a total deployment of 4,000 metric tons. 

3. Sichuan Tianfu International Airport
The terminal’s structural framework incorporates Yuantai Derun’s 90×250×20mm reshaped tubes, precision-engineered to meet aviation-grade load-bearing requirements.

• AIIB Headquarters (Beijing Chaoyang)
  The architectural core of this global financial hub integrates Yuantai Derun’s 500×520×22mm reshaped tubes.

• National Exhibition and Convention Center (Tianjin)
  At the landmark inaugural exhibition “China Construction Science Congress & Green Smart Building Expo” on June 24, 2021, Yuantai Derun Group supplied critical structural solutions for the venue’s development:

Key Contributions:

Custom S&R Tubes:
Specifications:
200×700×8mm, 200×700×10mm, 200×700×12mm, 200×700×16mm
200×800×8mm, 200×800×10mm, 200×800×12mm, 200×800×16mm
Applications:
• Primary column systems

• Cross-bracing frameworks

Tianjin Yuantaiderun Group operates a total of 10 hot-dip galvanizing production

lines. Among these, Yuantai Gongmao has 6 blow galvanizing lines, while Yuantai

Jianfeng has 4 lines (2 rack plating lines and 2 blow plating lines).

The hot-dip galvanizing processes at Tianjin Yuantaiderun Group are divided into two

types are blow plating and rack plating.

Blow Plating Details:

Standard zinc coating: Average of 200g (approximately 30μm).Note: 1μm ≈ 7g.

Maximum zinc coating: Up to 320g (approximately 45μm).

Minimum tube dimensions:Rectangular tubes: 20mm × 30mm.  Square tubes: 20mm × 20mm. 

Minimum wall thickness: 1.5mm.Risks for thinner walls (<1.5mm): Higher defect

rates due to weld seam cracking under strong airflow.

Limitation for thicker walls (>2.0mm): Inner diameter becomes too small for blow rods to enter, preventing internal coating.

Maximum tube dimensions:Rectangular tubes: 150mm × 200mm.Square tubes:

200mm × 200mm.

Maximum wall thickness: 5.75mm.Beyond 5.75mm: Tubes become too heavy for

magnetic rollers to lift, leading to inefficiency. Rack platzing is recommended.

Length range: 4m to 8m.（Because acid tanks and zinc pots are 1.5m deep × 1.5m wide × 9m long. Tubes exceeding 8m should use rack plating.）

Cost adjustments for low-tonnage orders: Small-volume orders incur additional fees due to setup requirements (e.g., configuring machines, dedicated blow heads, air rings, and rods).

Compatibility: Blow plating also applies to round pipes, ranging from 3/4 inches to 6 inches.

Rack Plating Details:

Standard zinc coating: Average of 60μm (approximately 400g).Note: 1μm ≈ 7g.

Maximum zinc coating: Up to 85μm (approximately 600g).

Maximum tube dimensions:Cross-section: 900mm × 900mm.  Length: Up to 12m.

Applicability:

Required for tubes with side lengths exceeding 200mm or wall thickness over 5.75mm (excluding 5.75mm).

Compatible with diverse materials such as angle steel, channel steel, flat steel, steel plates, solar brackets, straight-seam round tubes, seamless square&rectangular tubes, seamless round tubes, and various profiles.

Limitations:Welded components and small parts are excluded.Beacause acid tanks

and zinc pots are large (13m long × 1.5m deep × 1.5m wide). Processing small items

is inefficient, resulting in low output and profitability risks for the production line.

Next, we will provide a detailed introduction to the process flow.

1. Welded Tube Inspection

Purpose: Check raw tubes for bending/deformation and burrs at pipe ends.

Bending/deformation: Affects smooth operation in production lines, increasing defect risks.

Burrs: Prevent tubes from entering the equipment.

2. Acid Pickling

Procedure:Qualified tubes are immersed in acid tanks via overhead crane for 3–5

minutes.The crane lifts and lowers the tubes 3–5 times to ensure even pickling.

Total pickling time: 5–10 minutes. Inspect tubes to confirm complete rust removal.

Post-pickling handling:Lift tubes at a 15-de gree angle to drain residual acid.Allow

residual liquid to drain for 5–10 minutes before proceeding.

Common defects:

Under-pickling:

Causes: Insufficient removal of iron oxide scale, rust, or contaminants.

Result: Residual rust or debris on the tube surface.

Over-pickling:

Causes: Excessive pickling time, corroding the base metal.

Result: Rough/pitted surfaces, blackened appearance, or coarse black textures.

3. Rinsing

Purpose: Remove residual acid and iron salts from the tube surface. Residual

contaminants from the acid pickling tank can adversely affect galvanizing quality.

4. Flux Treatment

Remove residual moisture, iron salts, oxides, and other impurities from the

tube surface after rinsing.Prevent oxidation of the metal substrate (iron salts and

oxides can re-oxidize within seconds upon exposure to air and moisture).

Create a protective barrier to isolate the metal substrate from air, inhibiting

oxidation.Poor flux treatment can directly lead to uncoated areas.

Ensure the iron substrate reacts properly with molten zinc during immersion, forming

a continuous iron-zinc (Fe-Zn) alloy layer.This alloy layer is essential for adhesion

and corrosion resistance of the zinc coating.

5. Alignment

Inspect welded tubes and solvent-coated tubes to ensure smooth entry into the drying oven and subsequent galvanizing process.

6. Drying

Remove residual acid, water, and solvent from the tube surface.Inadequate drying can

cause explosions or violent splashing when tubes enter the zinc pot.

7. Galvanizing

Extend the service life of steel tubes by providing anti-corrosion and anti-rust

properties.

Mechanism:Galvanized tubes remain stable in dry air but form a protective oxide film

in humid environments (e.g., greenhouses), preventing oxidation.For exampl

galvanized tubes used in humid greenhouse conditions outlast untreated black steel

tubes.

8. External Blowing

Remove excess zinc nodules, zinc ash, flux residues, and other surface contaminants.

Enhance the gloss and uniformity of the zinc coating on both inner and outer surfaces,

improving durability.Optimize zinc layer thickness for material efficiency and cost

reduction.

9. Internal Blowing

Replace internal blowing nozzles according to tube specifications.Align the internal

blowing unit with the centerline of the galvanized tube.Regularly clean zinc nodules

adhering to the internal blowing equipment.If use hooks to reposition tubes if they fail

to align properly during the process.

10. Water Cooling

Submerge galvanized tubes in a water pool to cool them.Without cooling, the high

temperature of the tubes makes it impossible to handle or inspect the galvanizing

quality.

11. Inspection

Tubes are unloaded from the water pool via chains.Check for bending and uncoated

areas.If there are minor bare spots,repair using specialized zinc-rich paint.If

there are large uncoated areas,should set aside for re-galvanizing.When all the steps

passing inspection going to the next step.

12. Passivation Spraying

Prevent alkali efflorescence, moss-like growth, and corrosion.Ensure uniform

passivation layer via airflow to spread the solution evenly.Poor handling can lead to

zinc layer corrosion or white rust.

13. Marking

Use automated marking machines to print labels directly on tubes after passivation.

14. Bundling

Tubes are transported via rollers to automatic bundling machines.It is high efficiency

and reduced labor costs.

15. Affixing Certificates

Attach quality inspection certificates to approved products.

16. Warehousing

Rack Plating vs. Blow Plating

The processes for rack plating and blow plating are fundamentally similar. In

rack plating, after immersion in flux, steel tubes are secured with iron wire or

custom fixtures for hoisting. They are then galvanized, water-cooled, and passivated

directly using an overhead crane, eliminating the need for the tubes to pass through

production line machinery.

Founded in 2002 and headquartered in Tianjin’s Daqiuzhuang Industrial Hub, Yuantai Derun Group operates twin production bases in Tianjin and Tangshan. As a National Manufacturing Champion Enterprise, High-Tech Certified Company, and Top 500 Chinese Private Enterprise, we have dedicated over two decades to pioneering R&D, production, and distribution of structural steel tubing solutions.

Core Industry Applications
Our square & rectangular tubes are integral to emerging sectors including:

Prefabricated Construction

Smart Agriculture Infrastructure

Renewable Energy & Solar PV Systems

Marine Engineering Equipment
Trusted by industry leaders like China Railway Construction, State Power Investment Corp, and China Minmetals, our products empower mission-critical projects globally.

Technological Leadership

World-First Innovations:
• 1200mm ultra-large S&R tubes with single-pass forming
• Right-angle S&R tube manufacturing systems
• High-corrosion-resistant tube technology

Proprietary Advancements:
• Auto-die adjustment systems
• Intelligent seam welding technology
• In-line corner heating processes

Certified Excellence

CNAS-Accredited Labs: Ensuring global compliance through rigorous material testing (yield strength, elongation, weld integrity)

Advanced Material Engineering: Q490B, Q550D, SG700BL high-strength steels with weather-resistant properties

Global Certifications: ISO 9001/14001, CE, BV, JIS, ABS, and 12+ international standards

Integrated Manufacturing Ecosystem

Value-Added Processing:
• Hot-dip galvanizing & annealing
• On-site thermal bending & mega-diameter extrusion
• Custom cutting, drilling, and welding services

Flexible Ordering:
• Single-unit orders for non-standard specifications
• Multi-modal logistics (road/rail/sea) with consolidated billing

Standard-Setting Authority
As a key drafter of China’s S&R tube industry standards, including:

Mechanical Structural S&R Tubes

Architectural Structural S&R Tubes

Hot-Dip Galvanized Structural S&R Tubes

New Era of Growth
The launch of Tangshan subsidiary’s Zinc-Aluminum-Magnesium (ZAM) series marks our strategic pivot toward renewable energy markets. With a 10-million-metric-ton annual design capacity and unwavering commitment to innovation, Yuantai Derun Group continues to drive sustainable, high-quality growth across global infrastructure development.