Chemical Compatibility
Chemical compatibility is crucial for gasket selection because incompatible materials can degrade, swell, or embrittle, leading to leaks, equipment damage, contamination, and costly downtime.
Important Note: Chemical compatibility can vary significantly depending on the specific chemicals, their concentrations, and operating conditions (temperature, pressure, etc.).
Heat Resistance
Heat resistance is essential in gasket selection to ensure the material can maintain its integrity and sealing performance at elevated temperatures. Inadequate heat resistance can result in hardening, softening, or thermal degradation, leading to seal failure and system downtime.
Important Note: Heat resistance varies based on the material composition and must be matched to the application's maximum sustained and transient temperatures.
Compressibility
Compressibility measures a gasket’s ability to conform to surface irregularities and create a tight seal under pressure. A gasket with poor compressibility may fail to seal properly, especially on flanges with minor imperfections.
Important Note: Compressibility should be balanced with other properties like recovery and load-bearing to suit the specific application requirements.
Recovery
Recovery refers to a gasket’s ability to rebound after compression, helping to maintain the seal as flanges experience dynamic loads, temperature cycling, or vibration. Low recovery can result in a permanent set and seal loss over time.
Important Note: Recovery is especially important in applications with fluctuating operating conditions or thermal cycling.
Creep Relaxation
Creep relaxation is the loss of gasket stress over time while under constant load and temperature. Excessive relaxation can reduce sealing force and cause leaks.
Important Note: Selecting materials with low creep relaxation is critical for maintaining long-term sealing performance, particularly in high-temperature environments.
Erosion Resistance
Erosion resistance is the gasket’s ability to withstand material loss due to abrasive or high-velocity fluids. Poor erosion resistance can thin the gasket over time, compromising the seal.
Important Note: This property is vital in dynamic or high-flow applications such as pumps, valves, and chemical processing lines.
Compressive Strength
Compressive strength defines how much load a gasket can bear without crushing or deforming. Insufficient strength may lead to extrusion, blowouts, or gasket failure under high bolt loads.
Important Note: This is especially critical in high-pressure applications where the gasket is subjected to significant clamping forces.
Tensile Strength
Tensile strength measures a gasket material’s resistance to being pulled apart. While not always a primary selection factor, it becomes important during installation and handling.
Important Note: Gaskets exposed to stretching forces or those installed under tension benefit from higher tensile strength to avoid damage.
Shim Strength
Shim strength refers to a gasket’s ability to maintain a specific thickness under load without deforming or collapsing. It is critical in applications where precise spacing or alignment is required.
Important Note: Materials used as both gaskets and shims must exhibit high strength and dimensional integrity under pressure.
Dimensional Stability
Dimensional stability is the ability of a gasket to retain its shape and size over time and under varying temperatures and pressures. Loss of stability can lead to leakage and rework.
Important Note: Gaskets used in environments with frequent thermal cycling or moisture exposure must be highly dimensionally stable.