xingfeng low carbon steel flat washer galvanized din125 flat washer flat washer

A gasket is a mechanical seal between two objects, typically used to prevent leakage due to pressure, corrosion, and the natural thermal expansion and contraction of pipelines. Since the surface quality of machined parts cannot always be perfect, gaskets are used to fill any irregularities. Gaskets are usually made of sheet-like materials such as paper, rubber, silicone rubber, metal, cork, felt, neoprene, nitrile rubber, glass fiber, or plastic polymers (such as polytetrafluoroethylene). Gaskets for specific applications may contain asbestos.

Washers are thin plates (usually circular) with a hole (usually in the middle) and are typically used as load distribution fasteners. Other uses include as spacers, springs (Belleville washers, wave washers), wear-resistant pads, pre-display devices, and locking mechanisms. Rubber washers are also used in faucets (valves) to stop the flow of liquid or gas. Rubber or silicone washers can also be used to reduce fan vibration. Usually, the outer diameter of the washer is about twice the inner diameter.

A gasket is a mechanical seal between two objects, typically used to prevent pressure, corrosion, and the natural expansion and contraction of pipes. Since machined surfaces cannot always be perfect, shims are used to fill in any irregularities. Spacers are usually made from sheet materials such as paper pads, rubber, silicone rubber, metal, cork, felt, neoprene, nitrile butadiene rubber, fiberglass, or plastic polymers (such as Teflon). Gaskets for specific applications may contain asbestos.

The washer is a leak-proof component (usually located in the center) of a sheet (usually round), typically used for distributing loads and thread fasteners. Other applications include as spacers, springs (Belleville gaskets, wave gaskets), wear pads, pre-display devices, and locking devices. Rubber washers are also used in faucets (valves) to stop the flow of liquids or gases. Rubber or silicon shims may also be used to reduce fan vibrations. Usually, the outer diameter of the gasket is approximately twice the inner diameter.

Fold and edit this section type
According to their material and structural characteristics, gaskets can be divided into non-metallic gaskets, metal gaskets, and metal-non-metallic combination gaskets; further, various types can be subdivided into several categories.

Folding non-metallic gasket
Rubber gasket
Asbestos-free fiber rubber gasket
Flexible graphite metal composite gasket
Teflon gasket
Teflon-coated gasket
Other types of non-metallic material gaskets
gasket
gasket

Folding metal-nonmetallic composite gasket
Corrugated gasket
Metal wound gasket
Metal tooth compound gasket
Metal-coated gasket
Metal wave tooth composite gasket
Other types of metal composite gaskets
Folding metal gasket
Metal flat gasket
Metal corrugated gasket
Metal toothed gasket
Metal ring gasket
Metal lens gasket
metal O-ring pad
The metal ring gasket can be divided into

Octagonal ring pad
Elliptical ring pad
RX and BX type self-tightening ring pads
Fold and edit this section material classification
The portion of the washer located between the connector and the nut, usually a flat metal ring.

Metallic gasket; non-metallic gasket made of asbestos, rubber, synthetic resin, Teflon, and other non-metallic materials; a non-metallic coated gasket; non-metallic jacket gasket that includes a layer of synthetic resin, etc.

semimetallic gasket A gasket composed of metallic and nonmetallic materials, such as winding gasket, metal-coated gasket. a spiral wound gasket A gasket consisting of a metal belt with a V-shaped or W-shaped section and a non-metal belt. 1) The inner ring is a metal ring located in the inner ring of the winding gasket. 2) The outer ring is a metal ring located in the outer ring of the spiral wound gasket. b Metal cladding

metallic gasket – A metallic gasket made of metals such as steel, aluminum, copper, nickel, or monel.

The winding gasket refers to a metal belt (generally a V-shaped steel belt) and a non-metallic belt that are wound together into a ring gasket, with the metal and non-metallic belts wound alternately. Due to its excellent elasticity, it is widely used in petrochemical, chemical, electric power, and other industries for flange seal structures. Depending on the specific position, it can be placed in the inner or outer layer of the gasket, with a steel ring for positioning or reinforcement.

GB/T 4622.1-2009 Classification of winding gaskets

Gaskets for flanges of wound gaskets GB/T 4622.2-2008

GB/T 4622.3-2007 Technical specifications for winding gaskets

GB/T 9126-2008 Pipe flanges – Non-metallic flat gaskets – Dimensions

GB/T 9128-2003 Steel pipe flanges -- metallic ring gaskets -- Dimensions

Specification for non-metallic flat gaskets for pipe flanges

Specification for metal ring gaskets for GB/T 9 130-2007 steel pipe flanges

Gaskets for large-diameter steel pipe flanges

GB/T 13404-2008 Pipe flanges with non-metallic polytetrafluoroethylene-coated gaskets

Metal-coated gaskets for pipe flanges

GB/T 1906.1-2008 Dimensions of flexible graphite metal wave-tooth composite gaskets

GB/T 19066.3-2003 Flexible graphite metal wave tooth complex gaskets — Technical specifications

GB/T 1965.1-2005 Flexible graphite composite gaskets for metal punching plates used in pipe flanges – Dimensions

GB/T 1965.2-2005 Flexible graphite composite gaskets for metal punch plates used in pipe flanges — Technical specifications

JB/T 8_ Richard 1994 Asbestos rubber gaskets for pipe flanges

JB/T 8.89.194 Metal toothed gaskets for pipe flanges

JB/T 89-1994 Metal ring gaskets for pipe flanges

JB/T 9_0-1994 Winding gaskets for pipe flanges

JB/T 6_339-2005 Technical specifications for flexible graphite metal wound gaskets

JB/T 6_618 2005 Polyethylene tetrafluoroethylene tape for metal winding pads – specification

JB/T 8559-1997 Metal-covered gasket

JB/T L 0888-2006 Technical specifications for PTFE gaskets

JB/T L 089-2006 Expanded Polytetrafluoroethylene Sealing Tape Technical Specifications

SH 3 4011 1996 Asbestos rubber plate gaskets for pipe flanges

SH 3 402 1 996 Teflon-coated gaskets for pipe flanges

SH 3 403-1 996 Metal ring pads for pipe flanges

SH 3 407-1996 Winding gaskets for pipe flanges

HG/T20592~20635-2009 steel pipe flanges, gaskets, fasteners


GB/T L 047-2005 Definition and selection of pipe elements for DN (nominal size)

GB/T 1048-2005 Pipe element PN (nominal pressure) definition and selection

GB/T 11385-2008 Pipe flanges – Gasket performance test method

GB/T 1621-2008 Pipe flanges: Gasket stress relaxation test method

GB/T 12622 2008 Pipe flanges -- Test method for compression and resilience of gaskets

GB/T 20671.1-2006 Non-metallic gasket materials classification system and test methods – Part 1: Classification system of non-metallic gasket materials

Non-metallic gasket materials - Classification system and test methods - Part 2: Test method for compression rate and resilience of gasket materials

Non-metallic gaskets -- Classification systems and test methods -- Part 3: Test method for liquid resistance of gaskets

Non-metallic gasket materials - Classification system and test methods - Part 4: Test method for sealing of gasket materials

Non-metallic gaskets -- Classification systems and test methods -- Part 5: Test method for creep relaxation rate of gaskets

Non-metallic gasket materials - Classification systems and test methods - Part 6: Test method for adhesion of gasket materials to metal surfaces

GB/T 20671.7-2006 Non-metallic gasket materials – Classification system and test methods – Part 7: Test method for tensile strength of non-metallic gaskets

Non-metallic gasket materials – Classification systems and test methods – Part 8: Test method for softness of non-metallic gasket materials

Non-metallic gasket materials - Classification systems and test methods - Part 9: Test method for durability of cements of cork gasket materials

Non-metallic gasket materials - Classification systems and test methods - Part 10: Method for determining the thermal conductivity of gasket materials

Non-metallic gasket materials – Classification systems and test methods – Part 11: Method for determining the mildew resistance of synthetic polymer materials

GB/T 539-2008 oil-resistant asbestos rubber sheet

GB/T 540:2008 Test methods for oil-resistant asbestos rubber sheets

GB 9 1 2 - 0 8 Carbon structural steel and low alloy structural steel hot rolled sheets and strips

GB/T 3180-2007 Stainless steel cold-rolled steel plates and strips

GB/T 3985-2008 Asbestos Rubber Sheet

GB/T 4238-2007 Heat-resistant steel sheets and strips

GB/T 5574-2008 Rubber sheet for industrial use

GB/T 1253-2007 carbon structural steel cold-rolled sheets and strips

JB/T 6628-2008 Flexible graphite composite reinforced (plate) pad

JB/T 7.758.1-2008 Flexible graphite plates -- determination of fluorine content

JB/T 7.758.2-2005 Technical specifications for flexible graphite plates

JB/T 7.758.3-2005 Flexible graphite plates -- determination of sulfur content

JB/T 7.758.4 2008 Flexible graphite plates — determination of chlorine content

JB/T 7.758.5-2008 Flexible graphite plates -- determination of linear expansion coefficient

JB/T 7.758.6-2008 Flexible graphite plates -- test method for Shore hardness

JB/T 7.758.7-2008 Test method for stress relaxation of flexible graphite plates

JB/T 9_141.1-1999 Test method for density of flexible graphite sheets

Fold and edit the installation requirements for this section
Gaskets - Installation requirements for sealing gaskets

1. The sealing surface of the gasket and flange must be clean; there should be no scratches, stains, or other defects that could affect the sealing performance of the connection.

2. The outer diameter of the sealing gasket should be smaller than the flange sealing surface; the inner diameter of the sealing gasket should be slightly larger than the inner diameter of the pipeline. The difference between the two inner diameters is typically 2 times the thickness of the sealing gasket. This ensures that after compression, the inner edge of the sealing gasket does not extend into the container or pipeline, thereby preventing interference with the fluid flow within the container or pipeline.

3. The preload of the sealing gasket must not exceed the design specifications, in order to prevent excessive compression and loss of resilience of the sealing gasket.

4. When pressing the sealing gasket, it is advisable to use a torque wrench. For large bolts and high-strength bolts, a hydraulic tensioner is recommended. The tightening torque should be calculated based on the specified compression of the sealing gasket, and the oil pressure of the hydraulic tensioner must also be determined through calculation.

5. When installing the sealing gaskets, tighten the nuts in sequence. However, do not tighten them all at once to achieve the designed value. Typically, it should be tightened at least 2–3 times so that the stress distribution across the sealing gasket is uniform.

6. For pressure vessels and pipelines containing flammable and explosive materials, safety tools must be used when replacing sealing gaskets to prevent collisions between tools and flanges or bolts, which could lead to sparks, fires, or explosion incidents.

7. If there is leakage in the pipeline, the sealing gasket must be replaced or adjusted after pressure reduction treatment. Operating with pressure is strictly prohibited.

Fold and edit the applicable scope of this paragraph
The selection of gasket material primarily depends on the following three factors: temperature and pressure medium

I. Metal gasket material

1. Carbon steel: the recommended maximum operating temperature is no more than 538℃, especially when the medium undergoes oxidation. High-quality thin carbon steel plates are also not suitable for manufacturing equipment used with inorganic acids, neutral or acidic salt solutions. If carbon steel is subjected to stress, the accident rate in equipment operating under hot water conditions is very high. Carbon steel gaskets are typically used for high-concentration acid and many alkali solutions. The Brinell hardness is approximately 120.

2. 304 stainless steel, 18–8 (18–20% chromium, 8–10% nickel); the recommended maximum operating temperature is no more than 760℃. At temperatures between -196~538℃, stress corrosion and grain boundary corrosion are likely to occur. Brinell hardness: 160.

3. The carbon content of 304L stainless steel does not exceed 0.03%. The maximum operating temperature is no more than 760 °C. Corrosion resistance is similar to that of 304 stainless steel. The low carbon content reduces carbon precipitation from the lattice, and the resistance to grain boundary corrosion is higher than that of 304 stainless steel. The Brinell hardness is approximately 140.

4 316 stainless steel, 18-12 (18% chromium, 12% nickel); in 304 stainless steel, molybdenum content increases by approximately 2%. As temperature rises, its strength and corrosion resistance improve. At higher temperatures, it exhibits better creep resistance compared to other ordinary stainless steels. The maximum operating temperature is no more than 760 °C. The Brinell hardness is approximately 160.

5. The recommended maximum continuous operating temperature for 316L stainless steel is no more than 760℃~815℃. The carbon content is limited, and 316 stainless steel exhibits better stress resistance and grain boundary corrosion. The Brinell hardness is approximately 140.

6. Alloy 204: 45% iron, 24% nickel, 20% chromium, along with a small amount of molybdenum and copper. The recommended maximum operating temperature ranges from 760 °C to 815 °C. Particularly suitable for manufacturing corrosion-resistant equipment used in sulfuric acid production, with a Brinell hardness of approximately 160.

7. Aluminum – content must be no less than 99%. Aluminum possesses excellent corrosion resistance and machining properties, making it suitable for the production of double-clamp gaskets. Brinell hardness is approximately 35. The maximum continuous operating temperature does not exceed 426 °C.

8. Copper Copper has a composition similar to pure copper and contains trace amounts of silver to enhance its continuous operating temperature. The maximum continuous operating temperature is recommended to be below 260 °C. Brinell hardness is approximately 80.

9. Brass (66% copper, 34% zinc), under most operating conditions, has good corrosion resistance, but is not suitable for acetic acid, ammonia, salts, and acetylene. The maximum continuous operating temperature is recommended to be below 260 °C. The Brinell hardness is approximately 58.

10. Hastelloy B-2 (26–30% molybdenum, 62% nickel, and 4–6% iron). The maximum operating temperature does not exceed 1093 °C. It exhibits excellent corrosion resistance against hydrochloric acid at heat-resistant concentrations. It also demonstrates strong resistance to corrosion caused by wet hydrogen chloride gas, sulfuric acid, phosphoric acid, and reducing salt solutions. It possesses high strength under high-temperature conditions. The Brinell hardness is approximately 230.

1. Hastelloy C-276: 16–18% molybdenum, 13–17.5% chromium, 3.7–5.3% tungsten, 4.5–7% iron; the remainder is nickel. The maximum operating temperature does not exceed 103 °C. It exhibits excellent corrosion resistance. It shows excellent resistance to various types of cold nitric acid or boiling nitric acid at a concentration of 70%. It also possesses good corrosion resistance to hydrochloric acid and sulfuric acid, as well as excellent stress corrosion resistance. The Brinell hardness is approximately 210.

12. Incornel 600 nickel-based alloy (77% nickel, 15% chromium, and 7% iron). The maximum operating temperature does not exceed 103 °C. It exhibits high strength at high temperature conditions, commonly used to address stress-corrosion issues in equipment. At low temperatures, it demonstrates excellent co-processing properties. Brinell hardness is approximately 150.
A gasket is