12Cr2Mo1R is a steel plate for alloy boilers and pressure vessels, and it is a hydrogen-resistant (hydrogen service) container plate. The designation reads: 12 is the nominal carbon content (about 0.12%), Cr2 indicates about 2% chromium, Mo1 indicates about 1% molybdenum, and R indicates pressure vessel plate. It corresponds approximately to ASTM/ASME SA387 Grade 22 Class 2 in the 2.25Cr-1Mo family. The governing standard is the GB/T 713 series for steel plates for boilers and pressure vessels; verify the current edition, because the standard was updated from GB 713-2014 to GB/T 713-2023.
Standard and Delivery Condition
Per the applicable standard, plate dimensions, shape, weight, and allowable deviations should comply with GB/T 709, with thickness deviation normally per Class B and optionally per Class C. The standard delivery condition is normalized (accelerated cooling permitted) plus tempered; other conditions can be agreed by technical requirements. Thickness-direction properties (Z15, Z25, Z35) and ultrasonic examination can be specified. Ultrasonic testing is performed per JB/T 4730.3 or GB/T 2970 as required by the buyer.
Mechanical Properties
For plate thickness 6-150 mm, typical mechanical requirements for 12Cr2Mo1R are: tensile strength 520-680 MPa, yield strength at least 310 MPa, elongation at least 19%, and impact absorption energy of at least 34 J at 20°C. The 180° bending test with bending diameter d = 3a applies for plates with width b greater than 35 mm. The plate must also meet the impact performance at 1/2 plate thickness at -30°C and high-temperature tensile performance at 410°C as required for design conditions, which is why the steel is suitable for high-temperature and high-pressure service with long-term operation capability.
Chemical Composition and Metallurgy
12Cr2Mo1R has a controlled low-carbon composition with about 2.25% chromium and 1% molybdenum; the exact heat analysis is stated in the mill material certificate. Chromium provides oxidation and corrosion resistance at elevated temperature, while molybdenum provides creep strength and resistance to hydrogen attack. The steel is fully killed and fine-grain treated to ensure stable through-thickness properties and good weldability for thick-wall equipment.
Production Process
The production route is: primary refining, ladle furnace (LF) refining, vacuum degassing (VD) treatment, continuous casting (or ingot casting), cleaning and heating, rolling, stacking, surface inspection, batch processing, flaw detection, heat treatment (normalizing plus tempering), cutting and sampling, and performance inspection. The combination of clean-steel refining and controlled heat treatment is what guarantees the tight hardness, impact, and high-temperature tensile values required by the standard.
Cutting and Processing
After the plate is shipped from the mill and all performance indicators meet the requirements, cutting is carried out per the cutting process, and drawings are blanked. For plate thickness not greater than 20 mm, CNC plasma cutting or CNC laser cutting is preferred; for thickness greater than 30 mm, CNC flame cutting is usually chosen to control cutting accuracy and time. Preheating and controlled cutting speed help avoid hardening and cracking at the cut edge of Cr-Mo plate.
Frequently Asked Questions
Q1: What is 12Cr2Mo1R steel?
A1: A chromium-molybdenum alloy steel plate for boilers and pressure vessels per GB/T 713, used mainly for hydrogen service equipment; it corresponds approximately to SA387 Grade 22 Class 2.
Q2: What is the tensile strength of 12Cr2Mo1R?
A2: 520-680 MPa for plate thickness 6-150 mm, with yield strength of at least 310 MPa and elongation of at least 19%.
Q3: What is the delivery condition?
A3: Normalized (accelerated cooling permitted) plus tempered, per the standard.
Q4: What is the density of 12Cr2Mo1R?
A4: About 7.85 g/cm3, the same as other carbon and low-alloy steels; plate weight is thickness x width x length x density.
Q5: How is 12Cr2Mo1R plate cut?
A5: CNC plasma or laser cutting for thickness up to 20 mm, and CNC flame cutting for thickness above 30 mm, with preheat as required for Cr-Mo steel.
