Q345R
Q345R is a low-alloy steel specifically engineered for pressure vessel applications under GB/T 713 standards. Delivered in hot-rolled or normalized states, it combines exceptional strength (tensile ≤540 MPa) with enhanced weldability, making it ideal for boilers, heat exchangers, and multilayer container fabrication.
Applications
Core Industrial Uses:
Multilayer pressure vessels
Thick-walled components
- Shells (>36 mm)
- Tube sheets & flanges
- End caps (>50 mm requiring normalization)
Critical infrastructure: - LNG storage tanks
- Nuclear reactor auxiliary systems
Mechanical Property
Chemcial Composition
Welding Guidelines
Pre- & Post-Weld Protocols:
- Preheating:
- ≤34 mm thickness: Not required
- >34 mm: Preheat to 100–150°C
- Heat Treatment:
- Mandatory stress relief at 600–640°C for normalized plates >34 mm
- Cooling method: Air-cool to 400°C, then furnace-cool
- Energy Control:
- Low-carbon plates: Small linear energy (prevents grain coarsening)
- High-carbon plates: Larger linear energy (reduces martensite-induced brittleness)
Quality Assurance
Non-Destructive Testing (NDT):
- Ultrasonic Testing (UT) Requirements:
- 30–36 mm: Grade III (partial zones)
- >36 mm: Grade II (full coverage)
- >80 mm: Enhanced UT per design specs
Documentation:
- Mandatory Certificates:
- Mill Test Certificate (MTC) with actual yield/tensile ratios
- Heat treatment records
- Impact toughness reports (Charpy V-notch)
Why Choose Q345R?
- Cost-Efficiency: 15–20% weight reduction vs. conventional steels
- Safety Compliance: Meets hydrogen-induced cracking (HIC) resistance standards
- Versatility: Adaptable to ASME SA516 Gr70 equivalency
Types of steel we supply with high-quality
Frequently asked questions
Do you keep large quantities in stock monthly?
Yes, we are Baosteel's long-term first-level dealer, always keeping a large amount of steel in stock, and give priority to ordering and scheduling production at Baosteel Group as well as Xingcheng Special Steel.
Can we visit your office and the warehouse?
Of course, we welcome you to visit our office and warehosue. We can also show you all all the production lines of steel mills we cooperated with to more about our capacity and quality.
Do you have quality control system?
We have ISO, BV, SGS certifications and cand conduct product performance testing based on customer requirements.
Can you provide steel processing services?
We have multiple warehouses with long-term agreements, able to provide high-quality processing and packaging services to meet your requirement.
What are the payment methods?
We accept T/T and L/C. For other payment methods, please contact us for further communication.
How long is your delivery time?
For goods in stock , it takes 3 to 7 days.If we need to order from steel mills, it will take around 25-45 days depends on the specific products and different steel mills.
How do you keep long-term business and good relationship?
We always keep supplying good quality products with competitive prices and provide one stop service.We wish to establish long-term cooperative relationships with you, to achieve the best interests and to become the true friends.