Q345R is a Chinese national standard (GB 713-2014) low-alloy, high-strength steel plate designed specifically for pressure vessels and boilers, featuring minimum yield strength of≥345 MPa and tensile strength of 490--620 MPa. It is known for excellent comprehensive performance, weldability, and corrosion resistance, frequently used in energy, petrochemical, and industrial applications.
Key Specifications
"Q": Stands for Qu (Yield point).
"345": Represents the minimum yield strength of 345 MPa for thin plates.
"R": Stands for Rong (Pressure vessel).
Q345R material chemical composition:
| Grade | C % | Si % | Mn % | Cu % | Ni % | Cr% | Mo % | V % | Ti % | Alt % | P % | S % | Nb |
| Q345R | 0.20 | 0.55 | 1.2-1.7 | 0.30 | 0.30 | 0.30 | 0.08 | 0.050 | 0.030 | 0.020 | 0.025 | 0.010 | 0.050 |
Q345R material mechnical property:
| Thickness (mm) | > 3 ≤ 16 | > 16 ≤ 36 | > 36 ≤ 60 | >60 ≤ 100 | >100 ≤ 150 | >150 |
| Yield strength (≥Mpa) | 345 | 325 | 315 | 305 | 285 | 265 |
| Tensile strength (Mpa) | 510-640 | 500-630 | 490-620 | 480-610 | 470-600 | |
International Equivalents
Q345R is technically similar to these international standards:
USA: ASTM A516/A516M Grade 70 (or ASME SA516 Gr. 70).
Europe: EN 10028 P355GH.
Main Applications of Q345R
Boiler and Pressure Vessel Manufacturing: As a common low-alloy high-strength steel plate for pressure vessels, Q345R is widely used in manufacturing boilers (such as water-tube boilers, fire-tube boilers) and pressure vessels (including storage tanks, reactors, heat exchangers). It is suitable for equipment that bears medium pressure and temperature, and is the core material in the thermal power, petrochemical and chemical industries.
Petrochemical and Chemical Industry: It is used to make storage and transportation equipment for oil, natural gas, chemical raw materials (such as methanol, ethylene) and finished products. For example, it can be used to produce oil storage tanks, chemical reaction kettles and pipeline components, which can withstand the corrosion of general chemical media and ensure the safe operation of the equipment.
Thermal Power and Nuclear Power Industry: In thermal power plants, Q345R is used to manufacture boiler drums, header pipes and other key components that need to withstand high temperature and pressure. In nuclear power auxiliary equipment, it is also used to make low-pressure storage tanks and heat exchange equipment, meeting the strict safety and performance requirements of the nuclear power industry.
Metallurgical and Mining Industry: It is applied to the manufacturing of pressure equipment in metallurgical smelting processes, such as blast furnace gas storage tanks, converter cooling water tanks and mineral processing pressure vessels. Its good toughness and strength can adapt to the harsh working environment of high temperature, vibration and impact in the metallurgical and mining industry.
Municipal and Environmental Protection Industry: It is used to make urban gas storage tanks, water supply and drainage pressure pipelines, and environmental protection treatment equipment (such as sewage treatment pressure reactors). It has good weldability and formability, which can meet the installation and use needs of municipal infrastructure.
Application Conditions of Q345R
Pressure and Temperature Range: It is suitable for working conditions where the design pressure is not more than 10MPa and the design temperature is between -20℃ and 475℃. When the temperature exceeds 475℃, the material's high-temperature strength will decrease significantly; when the temperature is lower than -20℃, it needs to pass the low-temperature impact test to ensure toughness.
Medium Compatibility: It is applicable to neutral and weakly corrosive media, such as water, steam, oil, natural gas and general organic solvents. It is not suitable for strong corrosive media (such as concentrated acid, concentrated alkali, chloride-containing media) for a long time, otherwise it will cause material corrosion and reduce service life.
Welding and Processing Requirements: Before welding, the surface of the steel plate must be cleaned (removing rust, oil stains, oxides, etc.). Appropriate welding materials (such as E50 series electrodes) and welding processes should be selected to avoid welding defects such as cracks and pores. Post-weld heat treatment is required for thick plates (generally ≥12mm) to eliminate welding stress.
Quality Inspection Standards: The steel plate must meet the requirements of national standards (such as GB 713-2014). Before application, it is necessary to inspect the material's mechanical properties (tensile strength, yield strength, impact toughness), chemical composition and non-destructive testing (ultrasonic testing, radiographic testing) to ensure that there are no internal defects.
Working Environment Requirements: It should be used in a dry, well-ventilated environment. It should avoid long-term exposure to humid, high-temperature and high-humidity environments, so as to prevent surface corrosion. For outdoor equipment, anti-corrosion treatment (such as painting, galvanizing) should be carried out to improve the service life.
Total word count: About 490 words. Q345R is widely used in various industries relying on its excellent comprehensive performance, but it must be used in strict accordance with the above application conditions to ensure the safety and reliability of the equipment.
Packing
1.Seaworthy Packaging: We use strong, durable materials such as wooden pallets or crates to ensure the steel plates are securely packed for long sea voyages, preventing damage from movement.
2.Waterproof Wrapping: P420M is covered with high-quality waterproof materials to protect it from moisture and corrosion during transport, especially in humid environments.
3.Edge and Surface Protection: We apply edge protectors and use padded coverings to safeguard the steel from scratches and dents, ensuring that the material's surface and edges remain intact.
4.Custom Labeling and Marking: All shipments are clearly labeled with handling instructions and customer-specific requirements, facilitating smooth customs clearance and proper storage upon arrival.
Request a professional quotation for Q345R from GNEE Steel.
What is Q345R?
Q345R is a Chinese standard pressure vessel steel plate, belonging to low-alloy high-strength steel. It is widely used in manufacturing pressure vessels like boilers and storage tanks, with good toughness and weldability to adapt to harsh working conditions.
What standard does Q345R comply with?
Q345R complies with the Chinese national standard GB/T 713-2014. This standard specifies the technical requirements, test methods, inspection rules and other details for carbon and alloy steel plates for pressure vessels.
What is the minimum yield strength of Q345R?
The minimum yield strength of Q345R is 345 MPa (megapascals), which is the key index that defines its grade. This strength ensures it can withstand high pressure and load in pressure vessel applications.
What is the tensile strength range of Q345R?
The tensile strength of Q345R ranges from 470 MPa to 630 MPa. This range reflects the steel's ability to resist breaking under tension, making it suitable for pressure-bearing structures.
What is the chemical composition of Q345R mainly composed of?
Q345R's main chemical components include C (carbon), Si (silicon), Mn (manganese), P (phosphorus), S (sulfur), etc. Strict control of P and S content ensures good toughness and avoids brittleness.
What is the application scope of Q345R?
Q345R is mainly used to make pressure vessels such as boilers, steam drums, liquefied gas tanks, and chemical reactors. It is suitable for working environments with medium and low temperature and high pressure.
Is Q345R weldable?
Yes, Q345R has excellent weldability. It can be welded by common methods like manual arc welding, gas metal arc welding and submerged arc welding without special preheating.
What is the maximum thickness of Q345R steel plates usually supplied?
The maximum thickness of Q345R steel plates usually supplied is 200 mm, but it can be customized according to user needs. Thicker plates may require special heat treatment to ensure performance uniformity.
What is the impact toughness requirement of Q345R?
Q345R requires a certain impact toughness at room temperature or low temperature (usually -20℃). The average impact energy is not less than 34 J, ensuring it does not break brittlely under impact load.
Can Q345R be used at low temperatures?
Q345R can be used at low temperatures appropriately, generally down to -20℃. For lower temperature environments, it needs to pass strict low-temperature impact tests to confirm its toughness meets the requirements.