Q345R is a Chinese standard pressure vessel steel plate, specifically classified as low-alloy high-strength steel that complies with GB/T 713-2014. It is widely utilized in manufacturing pressure-bearing equipment such as industrial boilers, steam drums, liquefied petroleum gas tanks, and chemical storage vessels. Endowed with excellent toughness, superior weldability, and good pressure-bearing capacity, this steel grade can stably adapt to harsh working environments involving medium and low temperatures, high pressure, and occasional impact loads, ensuring the safe and reliable operation of related equipment.
Q345R Steel Plate Chemical Composition:
| Steel 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 Steel Plate Mechanical Property:
| Steel Grade | Thickness(mm) | Min Yield | Tensile | Elongation | Min Impact Energy | |
|---|---|---|---|---|---|---|
| Degree | Min J | |||||
| Q345R | 3-16 | 345Mpa | 510-640 Mpa | 21% | 0 | 41J |
| 16-36 | 325Mpa | 500-630 Mpa | 21% | 0 | 41J | |
| 36-60 | 315 Mpa | 490-620 Mpa | 21% | 0 | 41J | |
| 60-100 | 305 Mpa | 490-620 Mpa | 20% | 0 | 41J | |
| 100-150 | 285 Mpa | 480-610 Mpa | 20% | 0 | 41J | |
| 150-250 | 265 Mpa | 470-600 Mpa | 20% | 0 | 41J | |
Main Applications of Q345R
Boiler and Pressure Vessel Manufacturing: As a key low-alloy high-strength pressure vessel steel, Q345R is widely used in boilers (water-tube, fire-tube) and pressure vessels (storage tanks, reactors, etc.), suitable for medium pressure/temperature conditions in thermal power, petrochemical industries.
Petrochemical and Chemical Industry: It is applied to oil, natural gas and chemical material storage/transport equipment (oil tanks, reaction kettles, pipelines), resisting general chemical medium corrosion to ensure safe operation.
Thermal Power and Nuclear Power Industry: Used for high-temperature/pressure components (boiler drums, headers) in thermal power plants and low-pressure auxiliary equipment in nuclear power plants, meeting strict safety requirements.
Metallurgical and Mining Industry: Suitable for pressure equipment (blast furnace gas tanks, converter cooling tanks) in smelting, with good toughness and strength to adapt to high-temperature, vibrating working environments.
Municipal and Environmental Protection Industry: Used in urban gas tanks, water supply/drainage pipelines and sewage treatment equipment, with good weldability and formability matching infrastructure needs.
Primary Global Equivalents
| Standard | Equivalent Grade | Region |
|---|---|---|
| ASTM / ASME | A516 Grade 70 / SA516 Gr. 70 | USA |
| EN 10028-3 | P355GH / P355NH | Europe |
| JIS G3103 | SGV480 | Japan |
| DIN 17155 | 19Mn6 / HI / HII | Germany (Old) |
Detailed Comparison Highlights
ASTM A516 Gr. 70: This is the most common substitute. Both materials are used for moderate-to-lower temperature service. Q345R generally has slightly stricter control over Phosphorus and Sulfur than the base ASTM standard. ASTM A516 Grade 70 is the industry benchmark for carbon steel pressure vessel plates.
EN P355GH: The "P" stands for pressure, and "355" denotes the yield strength (355 MPa), which is very close to Q345R's 345 MPa. It is the standard European equivalent for boiler steels.
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Is Q345R a low-alloy steel?
Yes, Q345R is a low-alloy high-strength steel. Its alloy content (mainly manganese) is less than 5%, which improves strength on the basis of carbon steel while maintaining good processability and cost-effectiveness.
What is the delivery state of Q345R?
The standard delivery state of Q345R is normalizing (N). For special needs, it can also be delivered in hot-rolled (AR) state, but normalizing is preferred to ensure stable mechanical properties.
Can Q345R be bent or formed?
Q345R has good formability and can be bent, rolled and formed by cold or hot processing. The forming process should avoid excessive deformation to prevent cracks and ensure the dimensional accuracy of components.
Is Q345R resistant to corrosion?
Q345R has general corrosion resistance in atmospheric and mild environments. For corrosive media (like acid, alkali), it needs anti-corrosion treatment (such as painting, galvanizing, lining) to extend service life.
What is the welding material matching Q345R?
Welding materials matching Q345R include E50 series electrodes (for manual arc welding), ER50-6 welding wire (for gas metal arc welding), etc. The welding material should have similar strength and toughness to the base metal.
Can Q345R be used at high temperatures?
Q345R can be used at medium and low temperatures, generally up to 450℃. At higher temperatures, its strength will decrease, so it is not suitable for long-term use in high-temperature environments above 450℃.
What is the surface quality requirement of Q345R?
Q345R's surface should be free of cracks, folds, delaminations, scars and other defects. Minor surface defects can be repaired by grinding, but the thickness after repair must meet the standard.
How to store Q345R steel plates?
Q345R steel plates should be stored in a dry, ventilated warehouse to avoid moisture and rust. They should be placed on wooden pallets, away from corrosive substances, and covered with waterproof cloth if stored outdoors.
Can Q345R be used for high-pressure vessels?
Yes, Q345R is suitable for manufacturing medium and high-pressure vessels. Its high yield strength and good toughness can withstand the pressure load of high-pressure working conditions, but it needs to be designed and inspected in accordance with standards.
Can Q345R be used in chemical industry?
Yes, Q345R is widely used in the chemical industry. It is suitable for manufacturing chemical reactors, storage tanks for corrosive media (with anti-corrosion treatment) and other equipment.