Quality inspection standards for octagonal gaskets

1. A diagram is provided for reference, outlining the quantitative assessment of the surface quality of hard gaskets; this reflects the approach of technical personnel. 2. Grinding is carried out before installation to check the degree of fit between the contacting surfaces; this is the approach of construction workers. 3. Requirements must be clearly stated, and responsibilities must be defined. Otherwise, you set rules that require someone without any construction experience to make judgments, leaving them overwhelmed while having to take all the responsibility on themselves.

Check the gasket manufacturing standards for the implementation of the procurement plan. Everything you need is included in the standard.

Here’s the most practical method: apply red lead during reinstallation, rotate the gasket on the flange by 45°, and check whether the seal line remains continuous

Inspection upon material arrival 1.1 Upon the arrival of the materials, the engineer responsible for those materials shall examine the quality certification documents to confirm that they meet the requirements of the relevant design documents and standard specifications. The specifications, models, quantity, material type, nameplates, labels, packaging, as well as the appearance and integrity of the products shall also be checked in accordance with the drawings and relevant standards. 1. 2 Store the flanges for the ring connection surfaces and the metal ring gaskets separately according to different specifications. Clean the grease or rust preventive paint on the sealing surfaces using gasoline or acetone, and remove any surface rust with fine sandpaper of 400 grit or finer. 1. 3 Once all the flanges for the ring joints and metal gaskets have arrived, organize a inspection and handling team to conduct a thorough inspection of these flanges and gaskets, as well as carry out coordination tests. 2. Inspection, treatment, and fit testing of ring-connected flanges and metal gaskets 2.1 Inspection of ring-connected flanges and metal gaskets: Use a dial caliper to check the external dimensions of the sealing grooves on the ring-connected flanges as well as those of the metal gaskets, in accordance with the specified requirements. Those ring-connected flanges and metal gaskets that do not meet the standards are stored separately and reported to the project management team and the purchaser for replacement; those that pass the inspection are marked with a compliance label. The main checks involve verifying whether the dimensions of the sealing grooves on the flange of the ring connection surface, as well as those of the inner and outer rings of the metal gasket, are within acceptable limits. It is also checked whether the sealing surfaces of the flange and the metal gasket are smooth without any scratches, whether the thickness of the metal gasket meets the standards, and whether the depth of the sealing grooves on the flange meets the specified requirements. 2.2 Treatment of flanges with ring joints and metal gaskets: Flanges with ring joints and metal gaskets that have passed the dimensional inspection should be cleaned using gasoline or acetone; their sealing surfaces must be free from any dirt. Rough sealing surfaces can be lightly smoothed using fine sandpaper with a grit size of 400 or higher, after which they should be stored according to their specifications. 2. Test for the proper fit between the ring-connected flange and metal gaskets: Check the tight fit between each metal gasket and the ring-connected flange, and select the best metal gasket for each flange. Generally, if the gap between the metal gasket and the ring-connected flange is less than 0.1 mm as measured with a feeler gauge, the fit is considered satisfactory. After selecting the metal gasket for each ring connection flange, assign a uniform identification number to it (e.g., F-001 corresponds to D-001), and apply a thin layer of butter as a protective coating. When storing them, if conditions permit, it is best to clamp the flanges at the joint of the rings together and tie the metal gaskets with wire for storage; they should be retrieved together when needed. Analyze the defects identified through the testing; those metal gaskets and flange connections that cannot be repaired on-site are reported for replacement

1/ Visual inspection: The sealing surface of the octagonal gasket must be free of any penetrating defects and must not be distorted or deformed； 2. The flange sealing surface must be free of any through-holes; it shall also have no visible defects such as deformation or grooves. The sealing surface should be inspected using chalk powder, and if any defect is larger than 0.1 millimeters, it must be ground using grinding tools ； 3. Hardness should be applied to the sealing surfaces and gaskets; the hardness of the flange surface is generally 180, while the hardness of the gaskets is 30-40 units lower than that of the flange surface.