A387 Grade 5 Class 2 - high quality chromium-molybdenum alloy steel plate
A387 Grade 5 Class 2 - high quality chromium-molybdenum alloy steel plate, ideal for use in pressure vessels and industrial boilers due to it's excellent heat resistant and anti corrosion properties. We can supply plates from our own stockholding in Birmingham or directly from the mill and all plates come with mill test certification and individual stamping
Different Grades of ASTM / ASME Grade 5 Chromium-Molybdenum Alloy
Masteel's range of ASTM / ASME A387 Grade 5 chromium-molybdenum alloy products are available in different grades listed in the following.
ASTM A387 Grade 5 Class 2
ASME SA387 Grade 5 Class 2
Equivalent Grade of A387 Grade 5 Chromium-Molybdenum Alloy
The equivalent grade of A387 Grade 5 chromium-molybdenum alloy is as follows:
|
BS |
EN |
ASTEM/ASME |
DIN |
|
- |
- |
A387-22-2 |
- |
Chromium and Molybdenum Composition of A387 Grade 5 Chromium-Molybdenum Alloy
The chromium and molybdenum contents of A387 Grade 5 chromium-molybdenum alloy (according to the ASTM specification) are outlined in the following table.
|
Designation |
Nominal Chromium Content (%) |
Nominal Molybdenum Content (%) |
|
A387 Grade 5 |
5.00% |
0.50% |
Tensile Requirements for A387 Grade 5 Chrome Molybdenum Class 2 Plates
The tensile requirements for A387 Grade 5 chromium-molybdenum alloy Class 2 Plates are listed in the following table.
|
Designation |
Requirement |
Grade 5 |
|
A387 Grade 5 |
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) |
Chemical Composition of A387 Grade 5 Chromium-Molybdenum Alloy
The chemical composition of A387 Grade 5 chromium-molybdenum alloy from heat and product analysis is summarised in the following table.
|
Element |
Analysis |
Chemical Composition (%) inc. Grade & UNS No. |
|
Grade 5 (UNS: S50200) |
||
|
Carbon: |
Heat Analysis: |
0.15 max |
|
Manganese: |
Heat Analysis: |
0.30 - 0.60 |
|
Phosphorus: |
Heat Analysis: |
0.035 |
|
Sulphur (max): |
Heat Analysis: |
0.030 |
|
Silicon: |
Heat Analysis: |
0.50 max |
|
Chromium: |
Heat Analysis: |
4.00 - 6.00 |
|
Molybdenum: |
Heat Analysis: |
0.45 - 0.65 |
Tensile Test Requirements for Chromium-Molybdenum Alloy
The material shall be tested using a test specimen will confirm to the tensile requirements as outlined in tensile requirements for A387 Grade 5 chromium-molybdenum alloy Class 2 plates above.
Recommended Testing Procedures for Chromium-Molybdenum Alloy
The following requirements and testing procedures (which are not mandatory) are considered suitable for chromium-molybdenum alloy:
Vacuum treatment
Product Analysis
Additional Tension Test
Charpy V-Notch Impact Test
Drop Weight Test
High Temperature Tension Test
Ultrasonic Examination
Magnetic Particle Examination
1. How Does The Chemical Composition Of A387 Grade 5 Differ From Grade 11 Or Grade 12?
A387 Grade 5 is a higher-chromium alloy steel, typically containing around 5% chromium and 0.5% molybdenum. This places it between the more common Grade 11 (~1.25% Cr) and Grade 22 (~2.25% Cr), giving it distinct advantages in terms of oxidation resistance and elevated-temperature strength compared to lower-alloy grades, while potentially being more cost-effective than higher-chromium steels for specific service ranges.
2. What Are The Primary High-Temperature Service Advantages Of Using Grade 5 Class 2?
The primary advantage of A387 Grade 5 Class 2 lies in its superior oxidation resistance and higher strength retention at temperatures typically ranging from 540°C to 600°C (1000°F to 1112°F), exceeding the capability of Grade 11 or 12. This makes it suitable for components in catalytic crackers, reformer furnaces, and other severe petrochemical service environments where scaling and creep are significant concerns.
3. What Are The Critical Welding And Fabrication Considerations For A387 Gr.5 Cl.2?
Welding A387 Grade 5 Class 2 requires stringent procedures due to its higher alloy content. It demands mandatory preheating (usually 175-250°C / 350-480°F) and strict interpass temperature control to prevent hard, crack-sensitive microstructures. Furthermore, a mandatory Post-Weld Heat Treatment (PWHT) in the range of 675-730°C (1250-1350°F) is essential to temper the weld zone, relieve stresses, and restore corrosion resistance.
4. What Is The Standard Heat Treatment Condition For A387 Grade 5 Class 2 Plates?
A387 Grade 5 Class 2 plates are supplied in the Normalized and Tempered condition. Normalizing involves heating above the transformation range and air cooling to refine the grain structure, followed by tempering at a sub-critical temperature to achieve the optimal combination of strength and ductility specified in the standard (typically a minimum yield strength of 310 MPa / 45 ksi).
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
