Product description:

Square and rectangular sectioned steel pipes are collectively referred to as square and rectangular sectioned steel pipes, and they belong to a type of welded steel pipes. They are also known as "steel cold-formed sections".

Due to their unique cross-sectional shape and excellent mechanical properties, square and rectangular sectioned steel pipes are widely used in modern industries, construction and manufacturing, and have become an indispensable basic steel material.

The S355J2 (E355D) square steel pipe is a high-strength, low-alloy structural steel tube designed for demanding engineering and construction applications. Known for its excellent mechanical performance, impact toughness, and weldability, it is part of the EN 10025 and EN 10210 series of European structural steels widely used in buildings, bridges, machinery, and heavy equipment manufacturing.

The square cross-section of E355D steel pipe provides superior load-bearing capacity, stability, and resistance to bending and torsion, making it ideal for both static and dynamic load environments. It performs exceptionally well in low-temperature conditions, ensuring structural safety and durability even in harsh climates.

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Material Overview

S355J2 (EN 10025-2): A non-alloy structural steel grade with a minimum yield strength of 355 MPa and guaranteed impact toughness at –20°C (J2 designation). It offers outstanding performance in cold environments and high-stress applications.

E355D (EN 10210 / EN 10305-3): A seamless or welded precision structural steel with excellent formability and machinability, often used for mechanical structures and hydraulic systems that require high dimensional accuracy and a smooth internal surface.

Both grades share similar mechanical properties and are interchangeable in many structural and mechanical applications requiring strength, precision, and reliability.

Manufacturing Process

The production of S355J2 square steel pipes involves advanced forming and finishing technologies to guarantee high-quality mechanical and dimensional performance:

Billet Preparation: Premium-grade steel billets are carefully selected and heated.

Forming: Pipes are shaped through hot rolling, seamless extrusion, or ERW (electric resistance welding).

Cold Finishing: Cold drawing or sizing ensures smooth surfaces and precise dimensions.

Heat Treatment: Normalizing or annealing enhances uniformity and mechanical strength.

Surface Treatment: Black, pickled, galvanized, or coated finishes provide corrosion protection.

Inspection: Dimensional, mechanical, and NDT testing ensure compliance with EN and ISO standards.

Key Features and Advantages

High Structural Strength: Yield strength ≥355 MPa for heavy load applications.

Excellent Impact Toughness: Guaranteed performance at –20°C for cold-weather environments.

Superior Weldability: Compatible with all conventional welding techniques.

Excellent Dimensional Accuracy: Ideal for precision engineering and fabrication.

Good Corrosion Resistance: Available with galvanizing or coating protection.

Easy to Machine and Form: Allows cutting, bending, and drilling with minimal effort.

Long Service Life: Resistant to fatigue and mechanical wear.

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Applications:

The S355J2 (E355D) square steel pipe is widely used in high-strength structural and mechanical systems across multiple industries:

Construction and Infrastructure: Steel frameworks, columns, bridges, platforms, and stadiums.

Mechanical and Equipment Manufacturing: Crane arms, machine frames, conveyors, and heavy-duty supports.

Transportation and Automotive: Truck chassis, trailer frames, and vehicle reinforcements.

Energy and Hydraulic Systems: Pressure vessels, oil cylinder tubes, and structural supports.

Architecture and Furniture: Modern metal structures, railings, and frames.

Marine and Offshore Engineering: Structural components exposed to cold or corrosive environments.

Thanks to its strength, weldability, and low-temperature resistance, S355J2 (E355D) has become a trusted choice for demanding construction and mechanical engineering applications.

Surface Treatment Options

To ensure long-term durability and surface protection, S355J2 (E355D) square pipes can be treated using various finishing methods:

Hot-Dip Galvanizing: Provides excellent corrosion protection for outdoor and marine structures.

Pickling and Oiling: Removes oxide layers and prevents rust during transportation.

Powder Coating or Painting: Adds UV protection and aesthetic appeal.

Passivation: Improves corrosion resistance for stainless or alloy-coated surfaces.

Polishing (optional): For decorative or visible structures requiring smooth finishes.

Company profile:

Since its establishment in 2014, Wuxi Hengxin Zhicheng Co., Ltd. has rapidly grown into a leading enterprise in the steel manufacturing industry. We focus on the research, production and sales of seamless steel pipes, special-shaped steel pipes and hydraulic cylinders, and are committed to providing customers with high-quality, customizable products that fully meet diverse application needs.

Our products are exported to global markets such as the Middle East, South America, Africa, and Southeast Asia, and are highly trusted by large purchasers and customers in the steel industry. We always prioritize quality, reliability and customer service, and attach great importance to establishing long-term and stable cooperative relationships with customers. We provide each customer with tailor-made solutions.

We continuously promote technological innovation and improve service capabilities and production efficiency. Through an efficient online platform, you can browse our best-selling products at any time and communicate with the sales and support teams in real time to conveniently obtain the information you need. We sincerely invite partners from all countries to visit, exchange and provide guidance, and jointly explore more possible cooperation opportunities!

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Packaging and Transportation:

【Package standard】

We use steel bands to tightly package the products into hexagonal bundles. The structure is stable and not prone to deformation. Each bundle is equipped with two high-strength nylon straps to ensure the safety and convenience of the lifting operation.

To meet various maritime transportation needs, we offer a range of customized packaging options, including full coverage with oilcloth, moisture-proof wooden boxes, and high-strength protective frame packaging, to ensure the maximum safety of goods during transportation.

【Guarantee for transportation】

We offer 20-foot and 40-foot standard container transportation services. Each container can carry up to 25 tons of goods and we can accept trial orders with a minimum of 5 tons. This allows for flexible adaptation to your purchasing scale. All packaging complies with maritime shipping standards to ensure that the goods are delivered to the destination efficiently and safely.

Why us?

We focus on the research, development, production and sales of seamless steel pipes, special-shaped steel pipes and hydraulic cylinders. We have a complete production chain and an advanced equipment system, including piercing machines, cold drawing machines, hot rolling machines, high-precision flaw detection and testing equipment. The company has passed multiple authoritative certifications such as ISO9001, API, SGS, CCS, DNV, ABS, CE, RoHS, etc., ensuring that each product complies with international standards. We are committed to providing customers with high-quality, customizable solutions to meet diverse application needs.

Relying on our own built processing base and modern workshops, combined with multiple branches and storage centers across the country, we have achieved sufficient inventory and efficient logistics coordination, significantly shortening the delivery cycle and ensuring the rapid delivery of orders.

We have established a complete service and support system. After the order is signed, the professional after-sales team can provide timely and safe on-site guidance and technical support to ensure that customers are at ease throughout the process from procurement to use.

FAQ：

1. Do you support customized design and production?

Sure. We have a professional engineering team that can conduct customized design and production with special sizes, control systems or OEM according to your requirements.

2. How fast can you deliver?

In stock sizes, it takes 3-5 days. For customized sizes, it takes 30-35 days.

3. What payment methods do you support?

We support TT payment. Generally, 30% to 50% of the payment is made in advance, and the remaining amount is paid before shipment.

4. Can you provide material certification (MTC)?

Yes, we will provide MTC to you after production is completed to ensure that the material quality meets the standards.

5. What is the minimum order quantity?

Generally, we accept trial orders. The minimum order quantity is 1-3 tons, which can be determined according to different products.