1. Temperature resistance limitation
Poor high temperature stability
Long-term working temperature usually does not exceed 350℃. Graphite expansion is easy to occur in high temperature environment, resulting in a significant decrease in material strength.
Risk of low temperature brittleness
Brittle fracture may occur when the temperature is below -20℃, and special treatment processes are required to adapt to low temperature conditions.
2. Mechanical performance limitations
Limited pressure bearing capacity
The tensile strength (400-600MPa) is lower than that of carbon steel and other materials, and cannot meet the needs of ultra-high pressure pipeline systems.
Insufficient impact resistance
Although better than ordinary cast iron, its tolerance to severe vibration or high-frequency impact is still weaker than that of carbon steel.
3. Corrosion resistance defects
Weak chemical corrosion resistance
It is susceptible to corrosion in strong acid, strong alkali or high chloride ion environments, and requires additional protective measures such as surface coating.
Medium wear resistance
Compared with carbon steel or alloy steel, its hardness is lower, and it is easy to wear in fluids containing solid particles, affecting sealing.
4. Process and usage restrictions
Heavy weight
The material density is higher than that of lightweight materials such as plastic, which makes it more difficult to carry during installation and maintenance.
High maintenance cost
It is difficult to repair after damage, and usually requires overall replacement, which is especially economical when it is used in occasions with frequent opening and closing.
Limited application scenarios
It is mainly suitable for medium and low pressure (generally not exceeding PN16) and normal temperature environments. Other materials need to be used for high pressure, high temperature or corrosive extreme conditions.
5. Risks of special working conditions
Obvious thermal expansion and contraction
Long-term exposure to an environment with drastic temperature changes can easily cause deformation, and additional compensation space needs to be reserved.
Weak tensile bending resistance
If there is construction stress or external force distortion in the pipeline system, the valve body may be damaged.
By combining material properties with engineering practice, it is recommended to weigh the selection according to specific working conditions (pressure, medium, temperature, etc.), and use surface treatment or composite materials to optimize performance when necessary.
