What is the best way to cut ASME SA387 Grade11 Class1?
To cut ASME SA387 Grade 1 Class 1 (a Cr-Mo alloy steel for pressure vessels), the best methods depend on thickness and precision needs, with Plasma Cutting, Oxy-Fuel Cutting, and Waterjet Cutting being top choices, offering speed and accuracy, while considering the material's composition (chromium-molybdenum) that requires specific techniques for clean, precise cuts, often followed by grinding or machining for final edge quality.
The pressure vessel plates made of ASTM A387 Grade 11 (identical with ASME SA-387 Gr. 11) are chromium-molybdenum alloy steel plates intended primarily for welded boilers and pressure vessels designed for elevated temperature service. The ASME SA-387/ ASTM A387 Gr.11 steel has the nominal composition of 1.25Cr-0.5Mo-Si with UNS designation number of K11789 and P number of 4. There are two classes available according to tensile strength levels: Class 1 and Class 2.
ASME SA387 Grade 11 Class 1 Alloy Steel SA 387 Grade 11 Class 1 Coils are in high demand due to their ability to withstand both oxidisation and carbonization at high temperatures. It is a nickel-iron-chromium alloy with exceptional strength and great resilience to oxidation and carburization when exposed to high temperatures. Offering excellent high-temp strength and creep resistance (due to ~0.5% Mo), it is commonly used in refineries, power plants, and petrochemicals for its reliability in harsh, hot, corrosive environments, especially in sour gas applications.
ASME SA387 Grade 11 Class 2 Alloy Steel SA 387 Grade 11 Class 2 Sheets is a nickel and chromium alloy with good tensile strength, oxidation resistance, and carburzation characteristics. It was created with the goal of combining oxidation resistance, fabricability, and high-temperature strength.
Properties & Benefits
High-Temperature Performance: Excellent thermal strength and creep resistance.
Corrosion Resistance: Chromium provides good oxidation and corrosion resistance, ideal for sour gas.
Weldability: Good weldability for fabrication into critical equipment.
Key Characteristics
Material Type: Alloy Steel Plate.
Standard: ASME SA387 (ASTM A387 equivalent).
Grade: 11 (1.25% Chromium, 0.5% Molybdenum).
Class: 1 (specifies mechanical property requirements).
Applications: Boilers, pressure vessels, heat exchangers, reactors, high-temp storage, oil & gas, petrochemicals.
What are the typical application fields of ASME SA387 Grade 11 Class 1 steel?
ASME SA387 Grade 11 Class 1 steel is primarily used in high-temperature, high-pressure applications, especially in the oil & gas, petrochemical, and power generation industries, for equipment like pressure vessels, boilers, heat exchangers, piping, and storage tanks, benefiting from its chromium-molybdenum content for enhanced strength, creep resistance, and resistance to oxidation and corrosion, particularly in sour gas environments.
What precautions should be taken when welding ASME SA387 Grade 11 Class 1 steel?
When welding SA387 Grade 11 Class 1 steel (a low-alloy chromium-molybdenum steel), key precautions involve proper preheating (around 250°F/121°C minimum) to prevent cracking, selecting appropriate filler materials (like EB2 group), controlling interpass temperatures, applying Post Weld Heat Treatment (PWHT) (around 1200°F/650°C) to relieve stress, ensuring good ventilation, and using full Personal Protective Equipment (PPE), while cleaning the surface thoroughly.
Is ASME SA387 Grade 11 Class 1 carbon steel?
No,ASME SA387 Grade 11 Class 1 is not a carbon steel; it is a low-alloy chromium-molybdenum (Cr-Mo) steel.
While it contains carbon (typically between 0.05% and 0.17%), it is specifically categorized as an alloy steel due to the intentional addition of chromium and molybdenum to enhance its performance in high-temperature and high-pressure environments.
Equivalents
| BS | EN | ASTM/ASME | DIN |
| 621 B | ––– | A387-11-1 | ––– |
Specifications for ASTM A387 Grade 11 Alloy Steel Plates
| Designation | Nominal Chromium Content (%) |
Nominal Molybdenum Content (%) |
| A387 Grade 11 | 1.25% | 0.50% |
Chemical Composition Requirements
| Element | Heat Analysis |
Product Analysis |
|---|---|---|
| C | 0.05-0.17 | 0.04-0.17 |
| Mn | 0.40-0.65 | 0.35-0.73 |
| P | ≤0.025 | ≤0.025 |
| S | ≤0.025 | ≤0.025 |
| Si | 0.50-0.80 | 0.44-0.86 |
| Cr | 1.00-1.50 | 0.94-1.56 |
| Mo | 0.45-0.65 | 0.40-0.70 |
*All composition values are in %.
Alloy steel ASME SA387 GR. 11 CL. 1/ 2 Plates Mechanical Properties :
| Grade | Thickness | Yield strength | Tensile strength | Elongation in 2" 1) (min %) |
Elongation in 8" 1) (min %) |
|---|---|---|---|---|---|
| Grade 11 Class 1 | 0.185 - 3.60 4.70 - 91.4 |
35 | 60 - 85 | 22 | 19 |
1What is the maximum allowable stress value for ASME SA387 Grade11 Class1?
For ASME SA387 Grade 1 Class 1, the maximum allowable stress values are determined by ASME Section II, Part D (Table 1A), and vary significantly based on the operating temperature; for instance, at a typical temperature of $650^\circ\text{F}$ ($345^\circ\text{C}$), the allowable stress is approximately 13.8 ksi (95 MPa), but this value decreases as temperatures rise toward its upper limit of $1000^\circ\text{F}$ ($538^\circ\text{C}$) to account for reduced material strength and creep resistance.
2What is the ASME SA387 Grade11 Class1 standard?
ASME SA387 Grade 11 Class 1 is a chromium-molybdenum alloy steel plate for high-temperature pressure vessels and boilers, offering good creep, corrosion, and oxidation resistance, with lower strength but better elongation than Class 2, making it suitable for refineries and petrochemical plants in sour gas or hydrogen service. Key elements are ~1.25% Chromium (Cr) and ~0.5% Molybdenum (Mo), providing strength and stability for demanding environments, typically supplied normalized and tempered.
3What is ASME SA387 Grade 11 Class 1 material?
ASME SA387 Grade 11 Class 1 is a chromium-molybdenum (Cr-Mo) alloy steel plate, specified for welded boilers and pressure vessels needing high-temperature strength and corrosion resistance, common in oil, gas, and power industries, offering good oxidation/corrosion resistance, especially in sour gas, with Class 1 indicating specific, lower tensile strength requirements than Class 2.
4What is ASME SA387 Grade 11 Class 1 equivalent to?
ASME SA387 Grade 11 Class 1 is a chromium-molybdenum alloy steel primarily used for welded boilers and pressure vessels designed for elevated temperature service. It is virtually identical to ASTM A387 Grade 11 Class 1, with the primary difference being the governing regulatory code.
5What is the hardness of ASME SA387 Grade 11 Class 1 steel?
ASME SA387 Grade 11 Class 1 steel's hardness isn't directly listed in Brinell or Rockwell scales in typical spec sheets, but its yield strength is a key indicator, around 240 MPa (35 ksi), with tensile strength between 415-585 MPa (60-85 ksi), and it's usually supplied normalized and tempered, providing good strength for elevated temperature service in pressure vessels.
6What temperature is ASME SA387 Grade 11 Class 1 steel?
In the lower end of the temperature range SA 387 Gr 11 (1150 °F min tempering temperature) , and SA 387 Gr 22 (1250 °F min tempering temperature) are used. These grades can be specified in either class 1 or 2 and can also be provided in the Normalized & Tempered or Quenched and Tempered.
7What is the P number of ASME SA387 Grade 11 Class 1 steel?
The P-number for ASME SA387 Grade 11 Class 1 steel is 4. this assignment applies to both Class 1 and Class 2 of Grade 11, as they share the same nominal chemical composition of 1.25Cr-0.5Mo-Si. This grouping identifies the material as a low-alloy steel containing chromium and molybdenum, typically used for elevated temperature service in pressure vessels.
