Chinese 
Q355B Q345B A53 Gr.B S355JR STK490 Carbon Steel Pipe | High Strength Structural Tube
- Low alloy high strength design, 50% higher load capacity than Q235B grade
- Compatible with both new grade Q355B and old grade Q345B, multi-standard global equivalence
- Good low temperature toughness and welding performance, suitable for outdoor heavy engineering
- Complete large diameter & thick wall specifications, supporting heavy load structural design
- Supports post-processing such as galvanizing, 3PE anti-corrosion and fire-proof coating
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Product Overview
Q355B (formerly Q345B) is a low-alloy high-strength carbon structural steel pipe, which is the upgraded grade of Q235B for heavy load scenarios. Its international equivalent grades include **EN S355JR, ASTM A53 Grade B and JIS STK490 high strength level**, and it is widely used in load-bearing structural projects worldwide.
This pipe is manufactured by ERW welding or seamless process, produced in strict accordance with GB/T 1591, ASTM A53, EN 10210 and JIS G3452 standards. Available nominal pipe size covers NPS 1″ to 24″ (DN25 – DN600), with common wall thickness schedules including Schedule 40, Schedule 80, Schedule 160 and extra thick specifications. Standard length is 6m and 12m, custom length from 3m to 18m is available. Pipe end processing includes plain cut, welding bevel and threaded end.
Q355B / Q345B / S355JR carbon steel pipe is mainly used in heavy plant steel frames, bridge structural components, mechanical equipment bases, medium-pressure fluid pipelines, lifting equipment structures, port facilities and heavy support frames. We can provide secondary processing services such as cutting, beveling, galvanizing, 3PE anti-corrosion coating and fireproof coating.
Chemical & Mechanical Property Snapshot
Detailed Technical Specifications
Pipe Shape Options Table
Dimension Range Table
Product Comparison Table
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Drainage and Fluid Conveying Pipelines
Factory Building Columns and Beams
Building Steel Space Frame Structure
Product Packaging
Secure Export Packaging For Safe Handling And Delivery
FAQs
Q355B is the updated new grade of the original Q345B, with slightly improved yield strength index and optimized composition control. They can be substituted for each other in most engineering scenarios.
Yes. Q355B and EN S355JR have basically the same yield strength, tensile strength and impact performance, and are recognized as equivalent grades in international engineering.
Yes. Q355B grade has good strength and low temperature toughness, and is widely used in bridge structural components, heavy plant frames and load-bearing support structures.
Yes. We provide hot-dip galvanizing, 3PE/3PP anti-corrosion coating, epoxy coal tar pitch and other anti-corrosion treatments for outdoor and buried pipelines.
Standard sizes can be delivered within 7-10 working days after deposit; custom thick wall or large diameter orders need 10-15 working days.
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