What are the main reasons for flange gasket failure? Summary of Common Damage and Leakage Issues - Shanghai Hongguan, Hongguan Stainless Steel, Hongguan Special Materials

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What are the main reasons for flange gasket failure? Summary of Common Damage and Leakage Issues

2026-06-04

Flange gasket is the core component of pipeline and equipment flange sealing system. OnceFailure of flange gasketIt is prone to medium leakage, material leakage, pressure relief and other faults, which can seriously affect the safe and stable operation of the entire equipment. In actual working conditions,Reason for damage to flange gasketVery complex, commonly including improper installation and assembly, uneven bolt pre tightening force, flange sealing surface deviation, high and low temperature alternation, system pressure fluctuations, water hammer impact, medium corrosion aging, incorrect gasket selection, product quality defects, and many other situations. different materialsMetal wrapped gasket, rubber gasket, PTFE gasket, graphite gasketThe failure manifestations of damage, cracking, swelling, and creep relaxation are also different. To completely solve the problem of flange leakage, it is necessary to accurately determine the type of gasket failure and avoid common issues such as installation, working conditions, and material compatibility from the root.

1、 Installation and assembly issues (most common)

Improper pre tightening force of bolts

Loosening: The sealing surface is not tightly pressed, the medium leaks, and the gasket is bulging due to internal pressure;
Tight tightening: The gasket is excessively compressed, crushed, or torn, and the non-metallic gasket is flattened and loses rebound;
The bolts are not tightened properly in diagonal sections and are tightened on one side: the flange is skewed, and the gasket is locally compressed, overloaded, and broken.

Flange misalignment, warping, and excessive parallelism
Flange deformation and misalignment, uneven stress on the gasket, local compression damage, and erosion of the gasket by the medium through gaps.
Incorrect selection of gasket
Low pressure thin pads are used for high pressure, heat-resistant rubber pads are used for high temperature, and ordinary asbestos/rubber pads are used for corrosive media, with short-term swelling and brittle cracking.

2、 Temperature condition factors

Alternating cold and hot fatigue
The temperature of the start stop equipment fluctuates between cold and hot, and the gasket repeatedly expands, contracts, rebounds, and ages, resulting in cracks and fractures; Non metallic pads undergo high-temperature carbonization and low-temperature hardening and brittle cracking.
Overtemperature exceeding the design temperature
Exceeding the upper temperature limit of the gasket: rubber aging carbonization, graphite pad oxidation powdering, PTFE high-temperature creep collapse failure.

3、 Pressure fluctuations and medium erosion

Sudden changes in system pressure and water hammer impact
The instantaneous impact pressure of the start stop pump and valve penetrated the gasket, and the inner side was hollowed out and damaged by the impact of the medium.
Corrosion/swelling of the medium
Soaking in acid, alkali, oil, and organic solvents: Rubber swells and softens before extrusion; The metal wrapped pad steel strip has been corroded and perforated by the medium; Tetrafluoroethylene is swollen and cracked by special solvents.

4、 Sealing surface defect

Scratches, dents, rust, bumps, and gaps on the sealing surface of the flange, as well as the inability of the gasket to fill in the defects, can cause the high-pressure medium to slowly cut and damage the gasket.

5、 Quality issues with the gasket itself

Poor quality raw materials: insufficient rubber content, high graphite impurities, uneven thickness of metal strips;
Processing defects: Loose wrapping pad, detachment of spot welding, uneven thickness of gasket, local fracture under compression.

6、 External environmental aging

Outdoor pipelines are exposed to sunlight, rain, and ozone aging, causing rubber gaskets to harden and crack; Water vapor seeped into the interlayer of the wrapped gasket, corroded the steel strip, and the gasket disintegrated.

7、 Misuse of gasket installation auxiliary materials

The installation of the positioning ring on the winding pad is missing, excess filler is added, or the inner and outer diameter dimensions of the gasket do not match: the inner diameter is too small and washed away by the medium, and the outer diameter is too large and crushed by the flange.

8、 Creep relaxation (long-term service failure)

Long term high temperature and pressure cause creep of the gasket, resulting in continuous thinning of thickness and a decrease in sealing pressure, gradually leading to leakage and damage (metal winding and high incidence of PTFE gaskets).

Quick Tips for Distinguishing Failure Types

Single side tearing of gasket → uneven flange/uneven tightening under unbalanced load
The gasket is flattened and broken as a whole → the bolt is too tight/overheated
Internal hole erosion → medium erosion, water hammer
Foaming swelling → incorrect selection of medium corrosion