Alloy steel sheets are used in applications that require enhanced mechanical properties, such as
higher strength, toughness, and corrosion resistance, compared to carbon steel. Alloying
elements such as chromium, molybdenum, vanadium, and nickel are added to the steel to improve
its performance under high-stress or extreme conditions.
Here’s an overview of the key standards, material grades, and specifications for alloy steel
sheets:
1. Common Standards for Alloy Steel Sheets:
ASTM A387: This specification covers chromium-molybdenum alloy steel plates intended for use in
pressure vessels at high temperatures. Various grades like 2, 11, 12, 22, and 91 are commonly
used.
ASTM A514 / A514M: Standard for high-strength, quenched, and tempered alloy steel plates
intended for structural applications where high yield strength is required.
ASTM A533 / A533M: Standard specification for pressure vessel plates, alloy steel,
manganese-molybdenum and manganese-molybdenum-nickel.
ASTM A691: Specification for carbon and alloy steel sheets used in high-pressure services.
ASTM A829: This standard covers alloy structural steel plates primarily used for heat-treated
applications.
EN 10028-2: European standard for flat products made of steels for pressure purposes, including
low-alloy and alloy steels for elevated temperatures.
JIS G4105: Japanese Industrial Standard for chromium-molybdenum alloy steel used in
high-temperature service.
2. Material Grades for Alloy Steel Sheets:
ASTM A387 Grades 2, 11, 12, 22, 91: These grades of chromium-molybdenum alloy steel are designed
for pressure vessels and high-temperature applications. Grade 91 is a high-performance grade
used in critical applications such as power plants.
ASTM A514 Grade B: This is a high-strength, quenched and tempered alloy steel used for
applications requiring high tensile strength, such as heavy equipment frames and structures.
ASTM A533 Grade B: Manganese-molybdenum-nickel alloy steel sheets used in pressure vessels,
particularly in nuclear and high-stress environments.
SAE 4140 / AISI 4140: A chromium-molybdenum alloy steel with excellent toughness, wear
resistance, and strength, commonly used for tools and high-stress applications.
SAE 4340 / AISI 4340: A nickel-chromium-molybdenum alloy steel with superior toughness and
fatigue resistance, widely used in aerospace and automotive components.
EN 10028-2 P265GH / P295GH / P355GH: European standard for alloy steel plates for pressure
purposes at elevated temperatures.
3. Mechanical Properties:
Alloy steel sheets are designed to offer superior mechanical properties over carbon steel,
particularly in terms of strength, hardness, wear resistance, and toughness.
Tensile Strength: Ranges from 600 MPa to 1000 MPa depending on the grade and heat treatment
process.
Yield Strength: Can vary between 350 MPa and 800 MPa, with some high-strength grades exceeding
900 MPa.
Ductility: Many alloy steels maintain good ductility and toughness even at high strength levels,
allowing for cold and hot working.
4. Specifications:
Thickness: Alloy steel sheets are available in various thicknesses, typically ranging from 1.5
mm to over 100 mm depending on the application and required strength.
Width and Length: Common widths are 1000 mm, 1250 mm, and 1500 mm, and lengths can vary from
2000 mm to 6000 mm or custom dimensions.
Heat Treatment: Many alloy steel sheets are supplied in normalized, quenched, or tempered
conditions, which improves their strength, toughness, and overall performance.
5. Heat Treatment and Quenching:
Quenched and Tempered: Many alloy steel sheets are supplied in a quenched and tempered condition
to increase strength and hardness while retaining sufficient ductility.
Normalized: Heat treatment of alloy steels to refine grain structure and improve toughness,
particularly for pressure vessel applications.
6. Coatings:
Alloy steel sheets may also be supplied with coatings to protect them from corrosion, depending
on the environment in which they will be used. This can include:
Galvanizing: Zinc-coated alloy steel to improve corrosion resistance.
Painting or Powder Coating: Applied for additional corrosion protection, particularly in harsh
environments.
7. Applications:
Pressure Vessels and Boilers: Alloy steels like ASTM A387 Grades 11, 22, and 91 are commonly
used in boilers and pressure vessels due to their high-temperature strength and resistance to
creep.
Structural Applications: High-strength alloy steel sheets (ASTM A514, A829) are used in
structural applications such as bridges, cranes, and heavy equipment.
Aerospace and Automotive: SAE 4140, SAE 4340, and similar grades are often used in aerospace
components, automotive parts, gears, shafts, and other high-stress applications requiring
superior toughness and fatigue resistance.
Power Generation: Alloy steel sheets like ASTM A387 Grade 91 are used in the construction of
high-temperature components in power plants, such as steam boilers and turbines.
Summary of Common Grades:
Grade |
Yield Strength (MPa) |
Tensile Strength (MPa) |
Application |
ASTM A387 Grade 11 |
275–345 |
485–620 |
Pressure vessels, high-temperature applications |
ASTM A514 Grade B |
690 |
760–895 |
Structural applications, heavy equipment |
ASTM A533 Grade B |
345 |
620–795 |
Nuclear pressure vessels |
SAE 4140 / AISI 4140 |
655 |
950–1000 |
Tools, gears, shafts, and high-stress components |
SAE 4340 / AISI 4340 |
710 |
980–1080 |
Aerospace and automotive parts |
EN 10028-2 P355GH |
355 |
510–650 |
Pressure vessels and boilers |
8. High-Temperature Alloy Steel:
Creep Resistance: Grades such as ASTM A387 Grade 91 are designed to withstand long-term exposure
to high temperatures and resist creep (deformation over time under stress).
Oxidation Resistance: Chromium-rich alloy steels provide enhanced resistance to oxidation in
high-temperature environments.