Description: BBN steel is a well-known steel manufacturer and service provider in China, GB/T1591 Q345B steel plate,GB/T1591 Q345B low alloy steel plate is our superior product, we are favored by customers with high quality, competitive price and excellent service
Payment Terms: L/C, T/T, D/P, Western Union, Paypal, Money Gram
Complete Product LinesQ345B steel plates, steel coils, angle steel, round bars and customized steel profiles supplied for domestic and global customers.
Sufficient InventoryFull specifications in stable stock — plates 4–200mm thick, coils 1.3–25mm, round bars up to φ800mm, prompt delivery.
Strict Quality InspectionAll products strictly inspected by professional teams before delivery and offered at competitive factory prices.
01Product Overview & Execution Standards
GB/T 1591 Q345B is a high-strength low alloy structural steel manufactured per the GB/T 1591 standard. As a professional manufacturer and exporter with complete product lines, sufficient inventory and strict quality inspection systems, we supply Q345B steel plates, steel coils, angle steel, round bars and customized steel profiles for domestic and global customers.
Q345B delivers a yield strength of ≥345 MPa and tensile strength of 470–630 MPa with 20°C impact verification. It is widely applied in building and construction structures, machinery manufacturing, vehicles and general engineering fabrication, and can also be supplied against ASTM, AISI, JIS, DIN, BS and EN requirements for cross-standard projects.
Item
Specification Details
Steel Grade
GB/T 1591 Q345B
Executive Standard
GB/T 1591 (GB); ASTM, AISI, JIS, DIN, BS, EN applicable
Custom processing and fabricated steel profiles per client drawings
02Product Size Specifications
Four major product lines cover the full size range of Q345B low alloy steel — from thin coils and structural plates to large-diameter round bars.
01
Q345B Steel Plate
Thickness 4mm – 200mm · Width 1000mm – 3000mm · Length 3000mm – 12000mm. Hot-rolled structural plates for construction and machinery fabrication.
02
Q345B Steel Coil
Thickness 1.3mm – 25mm · Width 600mm – 1500mm. Suitable for structural forming, welded sections and continuous processing lines.
03
Q345B Angle Steel
Size range 20*20*3mm – 200*200*24mm · Thickness 3mm – 24mm. Equal angles for towers, structural frames and bracing members.
04
Q345B Round Bar
Diameter 4mm – 800mm, including inch specifications 0–1 inch, 1–2 inch, 2–3 inch, 3–4 inch and above 4 inch. Single piece length 3m, 6m, up to 9m.
Note: Other sizes and customized steel profiles are available on request — send us your drawing or size list and we will confirm feasibility, lead time and price.
03Equivalent International Steel Grades
GB/T 1591 Q345B low alloy steel corresponds to the following international standard grades, enabling flexible material replacement for global procurement and cross-standard project construction.
Standard Region
Standard Code
Equivalent Grade
European Union
EN
S355JR (1.0045)
USA
ASTM
A572A678 Gr.ASS Grade 50
Germany
DIN / WNr
St52-3
Japan
JIS
SM490ASS490
France
AFNOR
E36-2
Britain
BS
50B
Canada
HG
350W350WT
Europe (Old Standard)
EN
Fe510B
Italy
UNI
Fe510B
Belgium
NBN
AE355B
Spain
UNE
AE355B
China
GB
Q345BQ345C
Sweden
SS
Jan-32
International
ISO
E355C
Portugal
NP
Fe510B
India
IS
FE510-BIS961
Note: Equivalent grades match in general strength level and weldability, yet minor differences exist in specification details, tolerances and test requirements. For critical or long-cycle projects, please verify detailed project specifications before cross-standard replacement.
04Chemical Composition
Well-balanced low alloy chemistry per GB/T 1591 — a good combination of strength, toughness, weldability and formability for structural fabrication.
Element
C
Mn
Si
P
S
Max % (Heat Analysis)
≤0.20
≤1.70
≤0.50
≤0.035
≤0.035
Note: Values are specified maxima (heat analysis) per GB/T 1591. The moderate carbon and manganese design ensures reliable weldability together with the required structural strength.
05Mechanical Properties
Stable high-strength performance per GB/T 1591 — reliable strength, ductility and 20°C impact toughness for structural service.
≥345 MPaYield Strength (Min.)≈50 ksi
470–630 MPaTensile Strength68–91 ksi
≥20%Minimum Elongation50mm Gauge Length
20°CImpact Test TemperatureGrade B Requirement
Performance Index
Parameter Value
Tensile Strength
470–630 MPa
Yield Strength (Min.)
≥345 MPa
Elongation (Min., 50mm Gauge Length)
20%
Impact Test Temperature
20°C
Grade / Standard
GB/T 1591 Q345B
06Quality Assurance & Service
From mill inspection to global export — strict quality control, flexible custom processing and one-stop procurement service for customers worldwide.
1
Strict Quality Inspection
Complete inspection system operated by professional teams — all products inspected before delivery.
2
Stable Stock & Fast Delivery
Sufficient inventory of full specifications, with 5–10 day lead time for stock quantities.
3
Custom Processing
Customized steel profiles, cutting and processing per client drawings and technical requirements.
4
Global Export Service
Competitive factory prices, professional technical support and factory visits welcome for customers worldwide.
Full-series Q345B plates, coils, angle steel and round bars with stable quality
All products strictly inspected by professional teams before shipment
Customized steel profiles and processing services per client drawings
Competitive factory prices with fast and reliable global delivery
Get Your Q345B Steel Official Quotation
Send us your product type, size specification (or part drawings), quantity and processing requirements. We will reply with the latest stock status, competitive factory price and technical support within 24 hours. Customers from all over the world are welcome to visit our factory.
BBN Steel has established a complete set of production and supplier management system processes to ensure the improvement of product quality and better service to users.
Production Control
BBN Steel has established a complete production quality control process to ensure every link from research and development to mass production.
Supplier management
Our supplier selection will consider factors such as health and safety, ethics, environmental protection, price and quality to better serve customers.
Certification & Patent
We have successively won various international authoritative certifications, GB /T19001-ISO9001: 2000 quality management system was implemented.
After sales service
We provide booking space, shipping tracking service and after-sales service, we will always be first-class products and perfect pre-sale and after-sales service.
Get in Touch
Welcome to contact us through online consulting, emails and hotline if you are interested in our company or products. Our staff will reply you within 24 hours.
Address: HIGH-TECH DEVELOPMENT ZONE, ZHENGZHOU, CHINA
