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8 January 2026
High-Performance Low Alloy Structural Steel for Global Engineering Applications
In modern construction, infrastructure development, and heavy industry, the demand for high-strength, reliable, and cost-effective steel materials continues to grow. Among widely used structural steels, Low Alloy Steel Q345B and Q355B stand out for their excellent mechanical properties, good weldability, and broad application range. As standardized grades under China’s GB/T 1591 specification, these materials are widely recognized in both domestic and international markets as dependable low alloy structural steel solutions.
As a foreign trade enterprise specializing in steel export for over 18 years, we provide Q345B and Q355B steel products to customers worldwide, delivering stable quality, professional technical support, and one-stop export services tailored to diverse project requirements.
We are a professional foreign trade enterprise deeply engaged in the steel export industry for 18 years, accumulating rich experience and extensive global resources. Our professional team is composed of industry elites who are proficient in steel product knowledge, international standards, and global trade regulations.
Our advantages include:
Deep understanding of steel specifications and quality standards
Familiarity with international trade rules and export procedures
Strong insight into global market demand and regional policies
Excellent communication skills and customer-oriented service approach
From material selection and technical clarification to logistics coordination and after-sales support, our team provides all-round, one-stop professional services, ensuring smooth cooperation and reliable supply for customers across different countries and regions.
Q345B is a widely used low alloy structural steel grade with a minimum yield strength of 345 MPa. It offers a balanced combination of strength, toughness, weldability, and cost efficiency, making it suitable for general structural applications.
Q355B is the upgraded version of Q345B under the newer GB/T 1591-2018 standard, with a higher minimum yield strength of 355 MPa and improved mechanical performance consistency. It is designed to meet more demanding engineering and construction requirements.
Both grades are commonly supplied in the form of structural steel plate, steel sections, and fabricated components.
Compared with ordinary carbon steel, Q345B and Q355B provide higher yield and tensile strength, enabling structures to bear heavier loads with reduced material thickness. This helps optimize structural design and reduce overall project weight.
These steels are designed with controlled carbon equivalent (CE), ensuring good weldability without complex preheating procedures in most applications. This makes them suitable for large-scale fabrication and on-site welding.
Q345B and Q355B exhibit stable impact toughness, even under low-temperature conditions. This property is essential for structures exposed to cold climates or fluctuating environmental conditions.
As widely used low alloy structural steel, these grades provide an excellent balance between performance and cost, making them a preferred choice for large infrastructure and industrial projects.
Q345B and Q355B are extensively used as structural steel plate in a wide range of industries:
High-rise buildings
Bridges and overpasses
Stadiums and exhibition halls
Industrial plants and warehouses
Their high strength and reliable welding performance make them ideal for load-bearing structures and large-span constructions.
Construction machinery frames
Mining equipment
Lifting machinery and cranes
Heavy-duty industrial equipment
The durability and fatigue resistance of these steels ensure long service life under repeated mechanical stress.
Although not weathering steel like corten b steel, Q345B and Q355B are widely used in ship structures, offshore platforms, and port equipment due to their strength and processing flexibility.
Power plant steel structure
Wind power towers and components
Transmission towers
Their mechanical stability and dimensional consistency support long-term operational safety.
While corten b steel is known for its atmospheric corrosion resistance and weathering appearance, Q345B and Q355B focus more on structural strength and general-purpose performance.
Key differences include:
Corten B steel forms a protective rust layer and is used mainly for outdoor architectural or artistic structures
Q345B/Q355B prioritize strength, weldability, and versatility across industrial and construction applications
In some projects, Q355B structural steel plates are used in combination with corten b steel to balance strength and aesthetic or corrosion-resistance requirements.
All Q345B and Q355B products we supply are produced by qualified mills under strict quality control systems. Each batch can be provided with complete documentation, including:
Mill Test Certificates (MTC)
Chemical composition analysis
Mechanical property reports
Dimensional and surface inspection records
We support inspection by third-party organizations such as SGS, BV, or TUV to ensure compliance with customer specifications and international standards.
With 18 years of export experience, we have successfully supplied low alloy structural steel products to markets in:
Southeast Asia
Middle East
Europe
Africa
South America
We understand the different technical standards, certification requirements, and import regulations of various countries. Whether customers require compliance with GB, ASTM, EN, or equivalent standards, our team can provide professional guidance and matching solutions.
Our services go beyond product supply. We provide:
Material selection and technical consultation
Customized size and specification support
Export packing solutions for sea transportation
Logistics coordination and shipment tracking
After-sales technical support and communication
From inquiry to delivery, customers receive efficient, transparent, and reliable service throughout the entire cooperation process.
18 years of professional steel export experience
Stable supply of high-quality structural steel plate
Deep understanding of low alloy structural steel standards
Strong global logistics and trade coordination
One-stop, customer-oriented service model
Our goal is not just to supply steel, but to help customers succeed in their projects by providing dependable materials and professional support.
Low Alloy Steel Q345B (GB/T 1591-2008) and Q355B (GB/T 1591-2018) are widely trusted materials for construction, machinery manufacturing, infrastructure, and energy projects. With high strength, good weldability, and excellent cost-performance, they represent ideal choices in the field of low alloy structural steel.
As an experienced steel export enterprise with 18 years of industry expertise, we are committed to delivering high-quality structural steel plate products, professional technical support, and efficient international trade services. Whether your project involves standard construction steel or comparisons with materials like corten b steel, our team is ready to provide accurate solutions and reliable supply.
