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.
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 | |
Q345R Steel Plate Welding Feature:
When yield ratio is ≤ 0.75, more than 0.8 might have higher risk of crack forming. Preheating of steel plate welding is not required. When steel plate thickness is ≤34, preheat to 100 ~ 150 ℃ when steel plate thickness is > 34, additionally eliminate stress is needed after welding heat treatment, heating temperature range 600 ~ 640 ℃, usually air cooling after the heat preservation furnace cooling to under 400 ℃.
When the carbon content of partial minimum Q345R steel welding basic no strict limits on line, for it is overheating sensitivity is not high, cold cracking tendency is low, but for the goodness of plasticity and toughness overheated zone, small linear energy is better.
When welding Q345R steel of carbon content on the high side, for the hardening tendency increases, the content of martensite increases, it will cause the string cable energy cold cracking tendency increase, embrittlement of overheated zone also become serious, this situation is offline energy partial bigger is better.
Q345R Steel Plate Temperature Limit Due to Plate Thickness:
Steel plate thickness ＜6mm: no impact test, use temperature lower limit is - 20 ℃.
Steel plate thickness 6 ~ 20 mm: impact test at 0 ℃, temperature lower limit is - 20 ℃.
Steel plate thickness 20 ~ 25 mm, impact test at 0 ℃, temperature lower limit is- 10 ℃.
Steel plate thickness 25 ~ 200 mm, impact test at 0 ℃, temperature lower limit is 0 ℃.
Steel plate thickness > 20 ~ 30 mm hot rolled steel plate thickness controlled rolling state; supply agreement guarantee - 20 ℃ impact test, temperature limit for - 20 ℃.
Steel plate thickness > 20 ~ 200 mm, normalizing state; supply agreement guarantee - 20 ℃, temperature lower limit is - 20 ℃.
Common Applications
1.Petrochemical & Chemical Industries
Q345R is widely used for manufacturing equipment that stores or processes liquids and gases under pressure.
Pressure Vessels: Reactors, separators, and heat exchangers.
Storage Tanks: Oil, gas, and liquefied petroleum gas (LPG) storage tanks and spherical tanks.
Piping Systems: Industrial pipelines and associated components.
2.Power Generation
The steel's ability to perform reliably under elevated temperatures makes it suitable for power plants.
Boilers: High-pressure boilers and boiler drums.
Auxiliary Equipment: Components for steam turbines and nuclear power auxiliary equipment (non-high-temperature, non-high-pressure vessels).
3.Structural & General Engineering
Due to its good mechanical properties, including high strength and weldability, Q345R is also used in various structural applications, though its primary use remains in pressure-related fields.
Construction: Beams, columns, and frames for high-rise buildings and industrial plants.
Bridges: Main girders and supporting structures.
Heavy Machinery: Load-bearing components for cranes and mining machinery.
If you have project requirements for Q345R, we welcome your inquiry. GNEE maintains a large inventory of commonly used high strength steel grades for your selection.For detailed mechanical properties, chemical composition, and technical data, as well as free samples, please contact our factory immediately. We offer competitive prices, stable quality, and professional service. Email:beam@gneesteelgroup.com.
What heat treatment is Q345R usually subjected to?
Q345R is usually subjected to normalizing heat treatment. This process refines the grain structure, improves the steel's toughness and strength, and ensures the stability of its mechanical properties.
What is the difference between Q345R and Q345B?
Q345R is for pressure vessels, emphasizing impact toughness and weldability for pressure-bearing conditions. Q345B is general structural steel, with lower requirements on impact toughness and no pressure vessel-specific certification.
How to inspect the quality of Q345R steel plates?
Quality inspection of Q345R includes chemical composition analysis, mechanical property testing (tensile, yield, impact), ultrasonic flaw detection, surface quality inspection, etc., to ensure it meets standard requirements.
What is the density of Q345R?
The density of Q345R is about 7.85 g/cm³, the same as ordinary carbon steel. This density value is widely used in weight calculation and structural design of pressure vessels and related components.
Can Q345R be used to make boiler drums?
Yes, Q345R is a common material for boiler drums. Its good high-temperature resistance, pressure-bearing capacity and toughness can meet the working requirements of boiler drums under high temperature and high pressure.
What is the elongation requirement of Q345R?
The minimum elongation of Q345R is 21% (after fracture). Elongation reflects the plastic deformation ability of the steel before breaking, which is important for avoiding sudden failure of pressure vessels.
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 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.
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.
What is the hardness of Q345R?
The Brinell hardness (HB) of Q345R is usually between 137 and 179. Hardness is an important indicator of wear resistance and strength, and its value is related to heat treatment process.