1. Differences in chemical composition
| Material | Carbon content | Alloy element characteristics |
|---|---|---|
| WC6 | Medium carbon content | The proportion of chromium and molybdenum alloy elements is balanced, focusing on basic strength and corrosion resistance |
| WC9 | Slightly lower carbon content | Higher molybdenum content, enhanced high temperature stability and resistance to hydrogen embrittlement |
2. High-temperature performance comparison
Applicable temperature range
WC6: The upper limit of long-term temperature resistance is 593℃, which is suitable for medium-temperature high-pressure steam and oil and gas media.
WC9: The upper limit of temperature resistance is increased to 649℃, and the high-temperature oxidation and creep resistance are better, which is suitable for ultra-high temperature conditions (such as hydrogenation units).
High-temperature mechanical strength
Due to the higher molybdenum content, WC9 maintains higher tensile strength and yield strength at the same high temperature, reducing the risk of high-temperature deformation.
3. Application scenarios and adaptation standards
Typical application areas
WC6: Refinery, medium-temperature steam pipeline, conventional oil and natural gas transportation.
WC9: Synthetic ammonia production line, high-temperature hydrogenation reactor, supercritical steam system.
Material standard correspondence
WC6: Castings correspond to ASTM A217 C5, forgings match A182 F11, and pipeline material is A355 P11.
WC9: Castings correspond to ASTM A217 C12, forgings are compatible with A182 F22, and pipe material is A355 P22.
IV. Erosion and corrosion resistance WC9: Higher alloy ratio (especially molybdenum) enhances the ability to resist medium erosion, and is suitable for high-pressure environments containing corrosive media such as sulfur and hydrogen.
WC6: Conventional corrosion resistance meets the needs of non-extreme working conditions and is more cost-effective.
V. Selection recommendations WC6: Non-strongly corrosive scenarios with medium temperature ≤593℃ and pressure ≤42MPa.
WC9: Ultra-high temperature (≤649℃), strong erosion or high-pressure and severe working conditions with hydrogen-containing media.
WC6 and WC9 are both chromium-molybdenum steel valve materials. The core difference lies in the alloy ratio and high-temperature performance. They need to be selected comprehensively according to the temperature, medium characteristics and cost of the specific working conditions.