Is Q245R carbon steel ?
Yes, Q245R is a type of Chinese National Standard (GB 713) carbon steel specifically designed for boilers and pressure vessels. It is a low-carbon, high-toughness, and weldable steel (often referred to as a "mild steel" or "boiler steel" plate) used for fabricating intermediate-pressure containers and heat exchangers.
Q245R is a specific grade of steel plate for pressure vessels that complies with the GB/T 713 national standard of China. As a carbon-manganese steel, it is formulated to provide consistent mechanical properties across its thickness, which is generally limited to 200mm in standard production. The "245" indicates that for plates up to 16mm thick, the material will resist permanent deformation up to a pressure of 245 Newtons per square millimeter. It is widely used across Asia and in international projects following Chinese engineering specifications due to its proven track record in stationary pressurized equipment.
Key Characteristics
High Yield Point Stability: Maintains its 245 MPa minimum yield reliably across various production batches.
Excellent Machinability: Can be easily drilled, milled, or tapped to install nozzles, manways, and instrumentation.
Fusion Welding Quality (PVQ): Specifically tested to ensure that the welded joint can achieve the same strength as the base plate.
Low Sensitivity to Temper Embrittlement: Does not become significantly brittle after the heat cycles associated with welding.
Availability in Large Formats: Often produced in wide and long plates to minimize the number of weld seams in a vessel shell.
Grade Designation
Q: Stands for Yield Strength .
245: Minimum yield strength of 245 MPa.
R: Stands for Pressure Vessel .
Comparison (vs. P265GH)
Standard Context: Q245R is Chinese (GB); P265GH is European (EN 10028).
Yield Comparison: P265GH has a higher yield (265 MPa) compared to Q245R (245 MPa).
Temperature Testing: P265GH is specifically tested for "Elevated Temperature" properties (GH designation), whereas Q245R properties are defined for general service.
Documentation: P265GH requires 3.1 or 3.2 certification according to EN 10204; Q245R follows GB/T standard certification.
Common Application
Steam Header Manifolds: Large diameter pipes that collect steam from multiple boiler tubes.
Hydropneumatic Tanks: Pressure tanks used in water well systems to maintain system pressure.
Carbon Steel Filter Housings: Industrial-scale filtration units for water or non-corrosive liquids.
Flash Tanks: Used in steam systems to allow high-pressure condensate to "flash" into low-pressure steam.
Secondary Containment Vessels: Outer steel shells for hazardous material tanks to prevent environmental leaks.
How does Q245R perform under stress?
Q245R exhibits good performance under stress due to its moderate tensile strength and excellent low-temperature toughness. It maintains structural integrity in moderate stress conditions and is resistant to brittle fracture at low temperatures. This makes it ideal for pressure vessels and tanks that experience both high-pressure and low-temperature conditions.
What is the impact strength of Q245R?
Q245R has a good impact strength, which is important for applications in pressure vessels that may experience high internal pressure. The material is designed to resist fracture and maintain its integrity under stress, which is essential for pressure vessels used in industries like power generation and chemical processing.
How does Q245R perform at elevated temperatures?
Q245R performs well at moderate to high temperatures, with good resistance to thermal degradation. It is often used in applications where the operating temperature reaches up to 450°C (840°F). While it is not designed for high-temperature applications exceeding 500°C, its properties, such as strength and elongation, remain stable within the typical operating temperature ranges of most industrial processes.
| Steel Grade | Q245R and Q345R Chemical Composition % | |||||
|---|---|---|---|---|---|---|
| C | Si | Mn | P | S | Al | |
| Q245R | ≤0.20 | ≤0.35 | 0.50-1.00 | ≤0.025 | ≥0.020 | |
Mechanical Properties of Q245R Plate
| Thickness (mm) | |||||
| Q245R | > 3 ≤ 16 | > 16 ≤ 36 | > 36 ≤ 60 | >60 ≤ 100 | >100 |
| Yield strength (≥Mpa) | 245 | 235 | 225 | 205 | 185 |
| Tensile strength (Mpa) | 400-520 | 390-510 | 380-500 | ||
1. What industries use Q245R steel?
Q245R is commonly used in industries that require pressure vessels, boilers, and other equipment exposed to high pressure and moderate temperatures. These industries include power generation, chemical processing, oil and gas, and petrochemicals. Its weldability and strength at elevated temperatures make it an ideal choice for constructing pressure vessels and tanks in these industries.
2. What is the tensile strength of Q245R?
The tensile strength of Q245R ranges from 410 MPa to 550 MPa (60-80 ksi). This range ensures that Q245R is capable of withstanding substantial tensile forces while maintaining good resistance to failure. The material's ability to maintain strength at elevated temperatures makes it well-suited for use in pressure vessels, boilers, and reactors.
3. What is Q245R used for?
Q245R is a carbon steel grade used primarily in the manufacture of pressure vessels and boilers. It is commonly used in industries like power generation, chemical processing, and oil and gas. Its low carbon content and good weldability make it ideal for fabrication of equipment that will be exposed to both high pressure and moderate temperatures, including pressure vessels, heat exchangers, and reactors.
4. What is the chemical composition of Q245R?
The chemical composition of Q245R steel typically includes carbon (0.18-0.22%), manganese (0.60-1.20%), silicon (0.15-0.30%), phosphorus (≤ 0.035%), sulfur (≤ 0.035%), and a small amount of copper (≤ 0.20%). The balance is iron (Fe). This composition ensures a good combination of strength, weldability, and formability, making Q245R suitable for pressure vessels and boilers.
5. What is the yield strength of Q245R?
The yield strength of Q245R is typically around 245 MPa (35 ksi). This moderate yield strength allows it to withstand significant pressure in low-temperature environments without failure. This makes it an ideal choice for pressure vessels and other structural applications where both strength and toughness are needed under cryogenic conditions.
6. Can Q245R be welded?
Yes, Q245R has excellent weldability. It is commonly welded using standard welding techniques such as SMAW, GMAW, and GTAW. Preheating may be required for thicker sections to avoid cracking, particularly in low temperatures. Post-weld heat treatment can also improve the mechanical properties and reduce residual stresses in the welded joints, ensuring strength and integrity.
7. What is the maximum thickness of Q245R?
Q245R steel can typically be used in thicknesses ranging from 6 mm to 50 mm for pressure vessels. For thicker sections, additional heat treatment, such as normalizing or annealing, may be necessary to ensure consistent mechanical properties. The material can be used in a variety of thicknesses depending on the specific requirements of the pressure vessel or boiler construction.
If you want to learn more about Q245R GNEE's products, you can send an email toinfo@gneesteels.com . We are more than happy to assist you.
