What is the composition of ASTM A387 Grade 22 Class 2?
ASTM A387 Grade 22 Class 2 is a chromium-molybdenum alloy steel with key additions of 2.00-2.50% Chromium (Cr) and 0.90-1.10% Molybdenum (Mo), offering excellent high-temperature strength and corrosion resistance for boilers and pressure vessels, with typical maximums for Carbon (C) at 0.15%, Manganese (Mn) at 0.60%, Silicon (Si) at 0.50%, Phosphorus (P) at 0.035%, and Sulfur (S) at 0.035%.
ASTM A387 Grade 22 Class 2 steel is primarily utilized in the petrochemical and oil and gas industries for the fabrication of reactors, heat exchangers, and separators. These aggressive environments often involve high-pressure hydrogen gas, which can cause embrittlement in lesser materials. This specific alloy grade is designed to resist high-temperature hydrogen attack (HTHA), a phenomenon where hydrogen reacts with the carbon in the steel to form methane bubbles, leading to internal fissuring
What is the density of ASTM A387 Grade 22 Class 2 steel plate?
The density of this material is approximately 7.9 g/cm³ (490 lb/ft³). For practical estimation, a 1-inch thick plate weighs approximately 40.8 lbs per square foot.
How to calculate the weight of ASTM A387 Grade 22 Class 2 steel plate?
To find the weight for any thickness, multiply the thickness in inches by 40.8 lbs/ft².
Example: A 2-inch thick plate would weigh approximately 2 inches * 40.8 lbs/ft²/inch = 81.6 lbs/ft².
Dimension Range
|
Grade |
Product type |
Thickness |
Width |
Length |
|---|---|---|---|---|
|
Grade 22 |
Plate |
4.70 - 91.4 |
1500 - 3350 |
1900 - 15000 |
Chemical Requirements
| C | Mn | P | S | Si | Cr | Mo | V |
|---|---|---|---|---|---|---|---|
| 0.05 – 0.15 | 0.30 – 0.60 | 0.025 | 0.025 | 0.50 | 2.00 – 2.50 | 0.90 – 1.10 | – |
Tensile Requirements for Class 2 Plates
| Designation | Requirement | Grade 22 |
|---|---|---|
| A387 Grade 22 | Tensile strength, ksi [MPA] | 75 to 100 [515 to 690] |
| Yield strength, min, ksi [MPa]/(0.2% offset) | 45 [310] | |
| Elongation in 8 in. [200mm], min % | ||
| Elongation in 2 in. [50mm], min, % | 18 | |
| Reduction of area, min % | 45 (measured on round specimen) 40 (measured on flat specimen) |
1What are the typical application fields of ASTM A387 Grade 22 Class 2?
ASTM A387 Grade 22 Class 2 is a chromium-molybdenum alloy steel primarily used for high-temperature and high-pressure applications, especially in pressure vessels, boilers, and heat exchangers within the oil & gas, petrochemical, and power generation industries. Its excellent resistance to oxidation, creep, and corrosion at elevated temperatures makes it ideal for critical components like reactor vessels, piping, distillation columns, and high-pressure steam systems, where it maintains structural integrity under extreme stress and thermal cycling.
2What precautions should be taken when welding ASTM A387 Grade 22 Class 2?
When welding ASTM A387 Grade 22 Class 2 (a Cr-Mo steel), key precautions involve strict control of heat input, using low-hydrogen filler metals, implementing preheating to reduce cooling rates, controlling interpass temperatures, and performing post-weld heat treatment (PWHT) to prevent hydrogen cracking and maintain mechanical properties, alongside standard welding safety like proper PPE and ventilation.
3What is the P number of ASTM A387 Grade 22 Class 2?
The P-number for ASTM A387 Grade 22 Class 2 chromium-molybdenum steel is P5, as it falls within the 5% to 9% Chromium-Molybdenum steels group, used in pressure vessels and boilers, similar to other P5 materials like SA-182 F5 or SA-213 T5.
4What is the hardness of ASTM A387 Grade 22 Class 2 ?
For ASTM A387 Grade 22 Class 2, the Brinell hardness (HB) typically falls within the range of 150 to 180 HB, although some sources mention a slightly broader or different range like 130-170 HB, with the hardness being a result of its specific heat treatment and chemical composition (2.25% Cr, 1% Mo), providing higher strength than Class 1.
5What is ASTM A387 Grade 22 Class 2 equivalent to?
ASTM A387 Grade 22 Class 2 is a chromium-molybdenum alloy steel for high-temperature service, with key equivalents being ASME SA387 Grade 22 Class 2, EN 10CrMo9-10, and DIN 10CrMo9-10, along with British standard BS 622-515B. These standards denote similar chemical compositions and mechanical properties for pressure vessel applications requiring elevated temperatures.
6What welding rod for ASTM A387 Grade 22 Class 2 ?
For welding ASTM A387 Grade 22 Class 2 (a 2.25Cr-1Mo steel for high-temperature service), use matching or compatible chromium-molybdenum electrodes like E9015-B3, E9018-B3, or matching filler metals (e.g., ER90S-B3 for GMAW), often requiring preheat, interpass temperature control, and Post Weld Heat Treatment (PWHT) to prevent cracking and temper embrittlement, especially in high-temperature applications.
7What are Common Testing Requirements ASTM A387 Grade 22 Class 2 ?
ASTM A387 Grade 22 Class 2 requires specific mechanical properties, primarily Tensile Strength (75-100 ksi / 515-690 MPa) and minimum Yield Strength (45 ksi / 310 MPa), with 18% minimum elongation in 2 inches (50mm) and 40-45% reduction of area, alongside detailed chemical composition (Chromium ~2-2.5%, Molybdenum ~1%) and heat treatment (normalized/quenched & tempered), ensuring suitability for pressure vessels through mechanical tests like tensile, impact, and ultrasonic testing.
8What are the primary advantages of ASTM A387 Grade 22 Class 2?
ASTM A387 Grade 22 Class 2's primary advantages are its excellent high-temperature performance, superior oxidation/corrosion resistance (due to chromium & molybdenum), and good mechanical strength, making it ideal for welded boilers and pressure vessels in demanding oil, gas, and chemical service where heat and corrosive environments are common. Its key benefits include durability, weldability, and reliability at elevated temperatures, preventing issues like creep.
9How heavy is ASTM A387 Grade 22 Class 2 steel?
ASTM A387 Grade 22 Class 2 steel's "heaviness" (density) is about 7.9 g/cm³ (490 lb/ft³), but its weight depends on its dimensions (thickness, length, width); for example, a 1-inch thick plate weighs approximately 40.8 lbs per square foot, while a 3/4-inch plate is about 30.6 lbs/ft², as it's a chromium-molybdenum alloy used for pressure vessels with specific mechanical properties, not a fixed weight.
10What temperature is ASTM A387 Grade 22 Class 2 ?
ASTM A387 Grade 22 Class 2 is designed for high-temperature service, maintaining strength up to around 600°C (1112°F), with its tempering heat treatment often occurring around 675°C (1250°F) to provide good high-temperature creep resistance and low-temperature toughness for boilers, pressure vessels, and heat exchangers. Its chromium (2.25%) and molybdenum (1%) content enhance high-temperature strength and corrosion resistance, making it excellent for refining and chemical plants.
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