First, the material properties and chemical composition of the 12Cr1MoVR seamless steel pipe.
12Cr1MoVR is a low-alloy, high-strength steel specifically designed for pressure vessels. It belongs to the Cr-Mo-V alloy steel series. Its naming convention is as follows:
12: Carbon content approximately 0.12%; 
Cr: Contains chromium, improving corrosion resistance and heat resistance; 
Mo: Contains molybdenum, enhancing tensile strength and high-temperature stability; 
V: Contains vanadium, refining the grain size and improving toughness and strength; 
R: Represents "container plate" (the first letter of the container).
1. Chemical Composition Range of 12Cr1MoVR Seamless Steel Pipe (mass fraction): C: 0.08-0.15; Si: 0.17-0.37; Mn: 0.40-0.70; Cr: 0.90-1.20; Mo: 0.25-0.35; V: 0.15-0.30; P: ≤0.025; S: ≤0.010
2. Performance Characteristics of 12Cr1MoVR Seamless Steel Pipe:
- High-Temperature Performance: Maintains high oxidation resistance and thermal strength below 580°C, with endurance strength significantly superior to that of ordinary carbon steel. 
3. Mechanical Properties of 12Cr1MoVR Seamless Steel Pipe:
Tensile Strength ≥ 490 MPa; Yield Strength ≥ 245 MPa; Elongation ≥ 22%; Impact Absorbed Energy ≥ 71 J
Processability: Weldability is good, but preheating to 300°C before welding and stress relief treatment after welding are required. The pipe is sensitive to normalizing cooling rates, and Type II temper brittleness should be a concern during long-term use.
4. Applications of 12Cr1MoVR Seamless Steel Pipe:
- Petrochemical equipment (such as reactors and heat exchangers)
- Nuclear power plant pressure vessels
- Power plant boiler superheaters, headers, and main steam ducts
- High-temperature and high-pressure piping systems


Second, Processing Dimensions and Specifications of 12Cr1MoVR Seamless Steel Pipe
12Cr1MoVR seamless steel pipes are categorized by manufacturing process: hot-rolled (extruded) and cold-drawn (rolled). The standards implemented are GB 713-2014 (Standard for Steel Plates for Pressure Vessels) and GB 5310-2008 (Standard for Seamless Steel Pipes for High-Pressure Boilers).
1. Hot-Rolled Seamless Steel Pipe
Outer Diameter Range: 22-530 mm
Wall Thickness Range: 2.0-70 mm
Typical Specifications:
Small Diameter: 25×2.5 mm, 48×4 mm, 76×4 mm
Medium Diameter: 159×6 mm, 219×6 mm, 273×7 mm
Large Diameter: 325×8 mm, 377×10 mm, 426×12 mm
2. Cold-Drawn (Rolled) Seamless Steel Pipe
Outer Diameter Range: 10-108 mm
Wall Thickness Range: 2.0-13.0 mm
Typical Specifications:
Precision Steel Pipe: 38×3.5 mm, 57×3.5 mm, 89×4.5 mm
Thin-Wall Steel Pipe: 14×3 mm, 18×2 mm, 22×2.5 mm
3. Dimensional Deviation Requirements
Outer Diameter Deviation:
Grade D1: ±1.5% (Minimum ±0.75%) mm)
Grade D2: ±1.0% (minimum ±0.50 mm)
Grade D3: ±0.75% (minimum ±0.30 mm)
Wall Thickness Tolerance:
Thickness ≤ 20 mm: Upper limit +2 mm, lower limit -1.5 mm
Thickness 20-40 mm: Upper limit +3 mm, lower limit -2 mm
Ovality: For diameters ≤ 426 mm, ovality ≤ 2 mm; for diameters 426-630 mm, ovality ≤ 3 mm.
4. Weight Calculation Formula
The weight of steel pipe per meter (kg/m) can be calculated using the following formula: Weight = [(Outer Diameter - Wall Thickness) × Wall Thickness] × 0.02466


Third, Manufacturing Process and Quality Control of 12Cr1MoVR Seamless Steel Pipe
- Heat Treatment Process for 12Cr1MoVR Seamless Steel Pipe:
Normalizing + Tempering: Standard delivery condition, ensuring the material maintains long-term strength below 500°C.
Annealing/Tempering: Special delivery conditions can be agreed upon to improve processing performance. 12Cr1MoVR seamless steel pipe inspection standards:
Each pipe undergoes a hydrostatic test, expansion test, and flattening test.
The surface quality must be free of defects such as cracks, folds, and scars.