What Steels Are Commonly Utilized in Pressure Vessel Construction?
(1) Carbon Steel:
Carbon steel refers to the iron-carbon alloy containing less than 2.06% carbon. It possesses suitable strength, plasticity, good process performance, and cost-effectiveness, making it widely employed for manufacturing general medium and low-pressure vessels. Commonly used low carbon steels include the Q235 series (Q235A•F, Q235A, Q235B, and Q235C) and Q245R, which is a type of boiler steel. Q245R exhibits similar performance to high-quality carbon steel with lower sulfur content, providing higher strength. It is utilized at temperatures ranging from -20 to 475 ℃ for manufacturing medium and low-pressure vessels.
(2) Ordinary Low-Alloy Steel:
Ordinary low-alloy steel contains small amounts of alloy elements, enhancing its mechanical and process properties. One frequently used low-alloy steel in pressure vessel manufacturing is 16MnR, which contains approximately 1% more manganese than Q235 steel but boasts significantly higher strength. Containers made from this steel plate are around 30%40% lighter than those made from ordinary carbon steel. The operating temperature range is -20475℃. Additionally, low-alloy steels developed based on the country's resources, such as 15MnVR, 18Mn MoNbR, are often employed in manufacturing low-temperature containers at room temperature.
Table 1-1 Q235 series steel plate application range
(3) Steel for Containers Used Under Special Conditions:
① Steel for Low-Temperature Containers:
Steel used in containers operating at low temperatures (<-20℃) requires excellent toughness at the lowest service temperature to prevent brittle fracture during operation. Cryogenic vessels often utilize high-alloy steels like 06Cr18Ni9 and 06Cr18Ni9Ti, with a lower temperature limit of -196℃. Typically, vessels for low temperatures are constructed from manganese steel and manganese vanadium steel, such as 16MnDR and 09Mn2VDR. The lower limit of the operating temperature is determined by the impact value ak ≥ 34.3J/cm2 at -40℃, denoted as 16MnDR.
② Steel for High-Temperature Containers:
Containers operating in the temperature range of 400500℃ typically use low-alloy steels like manganese vanadium steel and manganese molybdenum steel, such as 15MnVR and 14MnMoVg. For temperatures of 500600℃, chromium-molybdenum low-alloy steels like 15CrMo and 12Cr2Mol are suitable. When the operating temperature exceeds 600℃ but remains below 700℃, nickel-chromium high-alloy steels such as 06Cr18Ni9, 06CrI8Ni9Ti, 10Cr18N9T, and 10Cr18Ni9Ti are preferred.
③ Steel for Hydrogen Corrosion Resistance:
For pressure vessels operating at 300 atm with hydrogen-containing media, the selection of suitable steels depends on the operating temperature. Below 200℃, high-quality carbon steel like No. 10 steel can be used. For temperatures below 350℃, low-alloy steels such as 15Mo and 30Mo are suitable. Chromium-molybdenum aluminum alloy steel like CrMo can be employed when the temperature is below 450℃. At higher temperatures, chromium-molybdenum alloy steel containing 0.5% vanadium is a viable choice.
Carbon steel refers to the iron-carbon alloy containing less than 2.06% carbon. It possesses suitable strength, plasticity, good process performance, and cost-effectiveness, making it widely employed for manufacturing general medium and low-pressure vessels. Commonly used low carbon steels include the Q235 series (Q235A•F, Q235A, Q235B, and Q235C) and Q245R, which is a type of boiler steel. Q245R exhibits similar performance to high-quality carbon steel with lower sulfur content, providing higher strength. It is utilized at temperatures ranging from -20 to 475 ℃ for manufacturing medium and low-pressure vessels.
(2) Ordinary Low-Alloy Steel:
Ordinary low-alloy steel contains small amounts of alloy elements, enhancing its mechanical and process properties. One frequently used low-alloy steel in pressure vessel manufacturing is 16MnR, which contains approximately 1% more manganese than Q235 steel but boasts significantly higher strength. Containers made from this steel plate are around 30%40% lighter than those made from ordinary carbon steel. The operating temperature range is -20475℃. Additionally, low-alloy steels developed based on the country's resources, such as 15MnVR, 18Mn MoNbR, are often employed in manufacturing low-temperature containers at room temperature.
Table 1-1 Q235 series steel plate application range
| Steel number |
design pressure P/MPa |
Operating temperature t/℃ |
Shell thickness δ/mm |
Matters need attention |
| Q235A·F | ≤0.6 | 0~350 | ≤12 | Must not be used for pressure vessels containing flammable and explosive media with medium, high or extremely hazardous media |
| Q235A | ≤1.0 | 0~350 | ≤16 | Must not be used for pressure vessels containing liquefied petroleum gas, highly toxic or extremely hazardous media |
| Q235B | ≤1.6 | 0~350 | ≤20 | Must not be used for pressure vessels containing highly toxic or extremely hazardous media |
| Q235C | ≤2.5 | 0~350 | ≤32 |
(3) Steel for Containers Used Under Special Conditions:
① Steel for Low-Temperature Containers:
Steel used in containers operating at low temperatures (<-20℃) requires excellent toughness at the lowest service temperature to prevent brittle fracture during operation. Cryogenic vessels often utilize high-alloy steels like 06Cr18Ni9 and 06Cr18Ni9Ti, with a lower temperature limit of -196℃. Typically, vessels for low temperatures are constructed from manganese steel and manganese vanadium steel, such as 16MnDR and 09Mn2VDR. The lower limit of the operating temperature is determined by the impact value ak ≥ 34.3J/cm2 at -40℃, denoted as 16MnDR.
② Steel for High-Temperature Containers:
Containers operating in the temperature range of 400500℃ typically use low-alloy steels like manganese vanadium steel and manganese molybdenum steel, such as 15MnVR and 14MnMoVg. For temperatures of 500600℃, chromium-molybdenum low-alloy steels like 15CrMo and 12Cr2Mol are suitable. When the operating temperature exceeds 600℃ but remains below 700℃, nickel-chromium high-alloy steels such as 06Cr18Ni9, 06CrI8Ni9Ti, 10Cr18N9T, and 10Cr18Ni9Ti are preferred.
③ Steel for Hydrogen Corrosion Resistance:
For pressure vessels operating at 300 atm with hydrogen-containing media, the selection of suitable steels depends on the operating temperature. Below 200℃, high-quality carbon steel like No. 10 steel can be used. For temperatures below 350℃, low-alloy steels such as 15Mo and 30Mo are suitable. Chromium-molybdenum aluminum alloy steel like CrMo can be employed when the temperature is below 450℃. At higher temperatures, chromium-molybdenum alloy steel containing 0.5% vanadium is a viable choice.
