Large Diameter Stainless Steel Washers

The attenuation of the mechanical properties of Large Diameter Stainless Steel Washers under high temperature conditions is an important consideration in their selection. Their high temperature creep behavior directly affects the long-term sealing performance of bolted connections in thermal cycles. According to the ASTM E139 test method for creep relaxation of metal materials, under the conditions of 350 degrees Celsius and an initial compressive stress of 200 MPa, the stress relaxation rate of 316L stainless steel after continuous loading for 1,000 hours is about 12% of the initial value, that is, the residual stress is still maintained at about 176 MPa. This stress level is sufficient to ensure that the sealing specific pressure of the flange connection surface is not lower than the critical value required by the design. According to the high-temperature allowable stress of materials in Volume II, Section D of the ASME Boiler and Pressure Vessel Code, the allowable stress value of 316L stainless steel at 400 degrees Celsius is 69 MPa, which is approximately 60% of the room temperature value of 115 MPa. Therefore, the design of large-diameter gaskets The thickness needs to be increased appropriately according to the operating temperature. Usually, the thickness needs to be increased by 10% to 15% for every 100 degrees Celsius increase to compensate for the decrease in material yield strength at high temperatures and ensure that the gasket has a sufficient safety margin in the connection of high-temperature pipe flanges and heat exchanger heads.

 

 

Under the combined action of low temperature environment and alternating loads, the impact toughness and fatigue resistance of large-diameter stainless steel washers have become key indicators that determine their applicability. According to the ASTM E23 Charpy impact test method, the impact absorbed energy of 316L stainless steel can still reach more than 200 joules at the liquid nitrogen temperature of minus 196 degrees Celsius, indicating that its austenite structure does not undergo ductile-to-brittle transition under cryogenic conditions. This characteristic makes this gasket suitable for flange connections of liquefied natural gas storage tanks and air separation equipment. According to the ASTM E466 axial fatigue test method, a large-diameter gasket with a thickness of 6 mm and an outer diameter of 180 mm is subjected to a cyclic load with a stress amplitude of 120 MPa. After two million cycles, no fatigue cracks appear on the surface of the gasket or the edge of the inner hole. Its fatigue limit is approximately 43% of the tensile strength of 280 MPa. The washer is provided with concentric annular grooves on the bearing surface in contact with the bolt head, with a groove depth of 0.1 mm and a spacing of 0.5 mm, according to DIN 946 friction coefficient measurement method, this microstructure can increase the friction coefficient of the bearing surface under dry friction conditions from 0.18 to 0.25, effectively resisting bolt rotation loosening caused by lateral vibration. At the same time, the groove can also accommodate a trace amount of grease, providing stable friction conditions in precision installations that require controlling the torque coefficient. Therefore, this washer is widely used in the fastening system of polar scientific research equipment brackets and deep-sea submersible pressure shells.

 

 

 

 

 

 

 

Obtain drawings from clients or produce drawings based on their samples or specifications.

The drawings, product raw materials, surface treatment, and other details are attested to by both parties.

 

 

 

 

Provide a quote, ensure that the order quantity is accurate, and include all relevant details,

such as the terms of payment, the terms of trade, the type of packaging, etc.

 

 

 

Follow the original drawings and samples exactly when producing the goods.

It was carefully packaged and delivered to the clients following a final inspection.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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