Jodith Valves 
March 24,2025
Regularly inspect the surface of stainless iron flanges for signs of corrosion, pitting, or mechanical damage. Visual inspection should cover all visible parts of the flange, including the flange face, bolt holes, and the connection area with the pipeline. Use appropriate lighting and magnifying tools if necessary to detect minor defects.
Keep the flanges clean to prevent the accumulation of dirt, debris, and corrosive substances. Use a soft brush and a suitable cleaning agent compatible with stainless iron to remove any deposits on the flange surface. Avoid using abrasive cleaners that may scratch the surface and accelerate corrosion. After cleaning, dry the flanges thoroughly to prevent water - induced rust.
For flanges with movable parts such as those in some types of joints, proper lubrication is crucial. Apply a high - quality anti - corrosion lubricant to the gasket surfaces and bolt threads. Lubricating the bolt threads not only facilitates easy tightening and loosening during maintenance or replacement but also helps prevent galling and seizing, which can occur due to repeated stress and vibration.
If significant corrosion has occurred, and the thickness of the flange has been reduced to a point where it may compromise the integrity of the connection, replacement is necessary. Corrosion that has penetrated through the flange wall or has caused extensive pitting over a large area is a clear indication for replacement.
Persistent leakage from the flange connection, despite attempts to tighten the bolts and replace gaskets, may suggest that the flange has been damaged. Leakage can be caused by warping of the flange face, cracks in the flange body, or damage to the gasket - seating surface, all of which may require flange replacement.
In case of mechanical damage such as cracks, dents, or fractures resulting from over - stress, impact, or improper installation, the flange should be replaced. Cracks, especially those that are growing or are in critical areas of the flange, can lead to sudden failure of the connection and pose a safety risk.
Before replacement, ensure that the pipeline system is depressurized, drained, and isolated. Identify the correct replacement flange in terms of size, pressure rating, and type (e.g., weld - neck, slip - on). Gather all necessary tools, including wrenches, cutting equipment (if required for removing the old flange), and new gaskets.
Carefully remove the bolts securing the old flange. If the bolts are stuck or corroded, use penetrating oil to loosen them. In some cases, it may be necessary to cut the bolts using a hacksaw or a cutting torch. After removing the bolts, carefully separate the old flange from the pipeline. If the flange is welded, appropriate welding removal techniques should be employed, taking care not to damage the adjacent pipeline sections.
Clean the mating surfaces of the pipeline where the new flange will be installed. Apply a thin layer of anti - seize compound to the bolt threads. Place the new gasket on the flange face and align the flange with the pipeline. Insert the bolts through the bolt holes and tighten them evenly in a cross - pattern to ensure proper sealing. If the flange is to be welded, follow the appropriate welding procedures, ensuring that the welding quality meets the relevant standards.
After installation, conduct a visual inspection to ensure that the flange is properly aligned and the bolts are tightened to the correct torque. Pressurize the system gradually and check for any signs of leakage at the flange connection. Monitor the system for a period to ensure the stability and integrity of the new flange installation.
Jodith is a manufacturer of all kinds of industrial valves, such as gate valve, globe valve, check valve, ball valve, butterfly valve, strainer, flange, and accessories.
