Introduction
With the rapid development of hydrogen energy infrastructure, the demand for large-diameter high-pressure storage cylinders continues to grow. AISI 4147 steel has emerged as an ideal material for manufacturing these critical components. This comprehensive analysis explores the impact of different quenching media on AISI 4147 steel properties.
Industry Background and Significance
Market Trends
- Gas cylinder diameters expanding to 508-610mm
- Strength grades advancing to SA-372 Class 70/110
- Growing hydrogen energy sector driving demand
Material Selection Importance
- Steel cylinders offer significant cost advantages
- High-pressure hydrogen environment demands superior performance
- AISI 4147 steel demonstrates exceptional compatibility
Experimental Methodology
Material Specifications
- Dimensions: Φ508 mm×39 mm seamless steel pipe
- Material grade: AISI 4147
- Sample type: Tile-shaped specimens
Heat Treatment Parameters
Water-Based Quenching Process:
- Heating temperature: 870°C
- Holding time: 90 minutes
- Quenching medium: 15% PAG water-based solution
- Tempering: 670°C for 60 minutes
Oil Quenching Process:
- Heating temperature: 870°C
- Holding time: 90 minutes
- Quenching medium: Mechanical oil
- Tempering: 670°C for 60 minutes
Performance Analysis Results
Hardness Comparison
Water-based quenching achieved slightly higher Rockwell hardness values, indicating faster cooling rates compared to oil quenching.
Tensile Properties
- Yield strength: Water-based ≈ Oil (890-900MPa)
- Tensile strength: Water-based ≈ Oil (1000-1025MPa)
- Elongation: Similar for both processes (approximately 21%)
Impact Toughness
Water-based quenching demonstrated marginally superior impact energy values, contributing to enhanced cylinder safety factors.
Industrial Application Guidelines
Optimal Process Selection
- Recommend water-based quenching for large hydrogen cylinders
- Both processes suitable for standard applications
- Consider specific production conditions
Quality Control Points
- Strict temperature control during quenching
- Ensure uniform cooling distribution
- Regular quenching media monitoring
Conclusions
AISI 4147 steel treated with 15% PAG water-based quenching solution demonstrates superior overall performance compared to traditional oil quenching, particularly for large-diameter hydrogen storage cylinders. The water-based process delivers higher martensite content and better hardenability, making it the preferred choice for critical applications.