What Are the Commonly Used Steels for Pressure Vessels?
(1) Carbon steel.
The iron-carbon alloy with a carbon content of <2.06% is carbon steel, which has appropriate strength and plasticity, good process performance, and low price, so it is widely used to manufacture general medium and low pressure vessels. Commonly used low carbon steels include Q235 series steel plates, Q245R, etc. Q235 series steel plates have four grades: Q235A•F, Q235A, Q235B, and Q235C. Q245R is a kind of boiler steel. Its steel plate and high-quality carbon steel have basically the same performance, and the sulfur content is lower than that of ordinary carbon steel, but has higher strength. The using temperature is -20 ~ 475 ℃, commonly used to manufacture higher medium and low pressure containers.
(2) Ordinary low-alloy steel.
Ordinary low-alloy steel is added with a small amount of alloy elements, so that it performs well in mechanical and process properties. The common low-alloy steel commonly used in the manufacture of pressure vessels is 16MnR (16MnR contains about 1% more manganese than Q235 steel, but its strength is much higher). The containers made of this steel plate are about 30%~40% lighter than that of ordinary carbon steel. The operating temperature is -20~475℃. In addition, low-alloy steels developing according to the country's resources, such as 15MnVR, 18Mn MoNbR, etc., are often used in the manufacture of 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 used for low-temperature (<-20℃) container requires good toughness at the lowest service temperature to prevent the brittle fracture of the container during operation. Cryogenic vessels are often made of high-alloy steel, such as 06Cr18Ni9, 06Cr18Ni9Ti, and the lower limit of their using temperature is -196℃. Generally, low temperature vessels are usually made of manganese steel and manganese vanadium steel, such as 16MnDR, 09Mn2VDR, etc.. The lower limit of the using temperature is the impact value ak ≥ 34.3J/cm2 at -40℃, then it can be used above -40℃, which can be written as 16MnDR.
②Steel for high-temperature containers, containers with a temperature in the range of 400~500℃, low-alloy steels such as manganese vanadium steel and manganese molybdenum steel are generally available, such as 15MnVR, 14MnMoVg, etc. When the using temperature is 500~600℃, chromium molybdenum low-alloy steel can be selected, such as 15CrMo, 12Cr2Mol, etc.; when the using temperature is 600~700℃, nickel-chromium high-alloy steel can be selected, such as 06Cr18Ni9, 06CrI8Ni9Ti, 10Cr18N9T, 10Cr18Ni9Ti, etc.
③The steel for hydrogen corrosion resistance, according to the domestic and foreign experience, the pressure vessel with the working pressure of 300 atm and the medium containing hydrogen can choose some of the following steels according to different using temperature. When it is lower than 200℃, high-quality carbon steel can be used, such as No. 10 steel; when it is lower than 350℃, low-alloy steel can be used, such as 15Mo and 30Mo; when the temperature is lower than 450℃, chromium molybdenum aluminum alloy steel such as CrMo can be used. When used at higher temperatures, chromium-molybdenum alloy steel containing 0.5% vanadium can be used.
The iron-carbon alloy with a carbon content of <2.06% is carbon steel, which has appropriate strength and plasticity, good process performance, and low price, so it is widely used to manufacture general medium and low pressure vessels. Commonly used low carbon steels include Q235 series steel plates, Q245R, etc. Q235 series steel plates have four grades: Q235A•F, Q235A, Q235B, and Q235C. Q245R is a kind of boiler steel. Its steel plate and high-quality carbon steel have basically the same performance, and the sulfur content is lower than that of ordinary carbon steel, but has higher strength. The using temperature is -20 ~ 475 ℃, commonly used to manufacture higher medium and low pressure containers.
(2) Ordinary low-alloy steel.
Ordinary low-alloy steel is added with a small amount of alloy elements, so that it performs well in mechanical and process properties. The common low-alloy steel commonly used in the manufacture of pressure vessels is 16MnR (16MnR contains about 1% more manganese than Q235 steel, but its strength is much higher). The containers made of this steel plate are about 30%~40% lighter than that of ordinary carbon steel. The operating temperature is -20~475℃. In addition, low-alloy steels developing according to the country's resources, such as 15MnVR, 18Mn MoNbR, etc., are often used in the manufacture of 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 used for low-temperature (<-20℃) container requires good toughness at the lowest service temperature to prevent the brittle fracture of the container during operation. Cryogenic vessels are often made of high-alloy steel, such as 06Cr18Ni9, 06Cr18Ni9Ti, and the lower limit of their using temperature is -196℃. Generally, low temperature vessels are usually made of manganese steel and manganese vanadium steel, such as 16MnDR, 09Mn2VDR, etc.. The lower limit of the using temperature is the impact value ak ≥ 34.3J/cm2 at -40℃, then it can be used above -40℃, which can be written as 16MnDR.
②Steel for high-temperature containers, containers with a temperature in the range of 400~500℃, low-alloy steels such as manganese vanadium steel and manganese molybdenum steel are generally available, such as 15MnVR, 14MnMoVg, etc. When the using temperature is 500~600℃, chromium molybdenum low-alloy steel can be selected, such as 15CrMo, 12Cr2Mol, etc.; when the using temperature is 600~700℃, nickel-chromium high-alloy steel can be selected, such as 06Cr18Ni9, 06CrI8Ni9Ti, 10Cr18N9T, 10Cr18Ni9Ti, etc.
③The steel for hydrogen corrosion resistance, according to the domestic and foreign experience, the pressure vessel with the working pressure of 300 atm and the medium containing hydrogen can choose some of the following steels according to different using temperature. When it is lower than 200℃, high-quality carbon steel can be used, such as No. 10 steel; when it is lower than 350℃, low-alloy steel can be used, such as 15Mo and 30Mo; when the temperature is lower than 450℃, chromium molybdenum aluminum alloy steel such as CrMo can be used. When used at higher temperatures, chromium-molybdenum alloy steel containing 0.5% vanadium can be used.
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