What is a metal spiral wound gasket? A comprehensive analysis of universal industrial pipe sealing

In chemical engineering, thermal power, power plants, petroleum, pressure vessels, and piping engineering, the vast majority of leakage failures stem the failure of small flange gaskets. Ordinary rubber gaskets are not resistant to high temperatures, PTFE gaskets are not resistant to high pressure, and pure metal gaskets have relatively hard sealing properties., with its composite structure of "metal skeleton   flexible filler," the metal-jacketed gasket balances elasticity, sealing, and resistance to high pressure and high temperature. It is currently most widely used and versatile sealing gasket for medium-to-high pressure and high-temperature piping applications, known as the "universal gasket" in the industrial sealing industry. 

 I What is a metal-jacketed gasket? A metal-jacketed gasket (full name: metal-wound gasket) is a semi-metal composite sealing gasket made by alternatelyally winding a metal strip and a flexible filler strip, and then precisely compressing them. Common structures are divided into four types: basic type, inner ring type, outer ring type, inner/outer ring type. The metal part provides strength and pressure-resistant support, while the flexible filler is responsible for filling gaps and providing resilient sealing, perfectly solving the problems of traditional gaskets being "too hard and leaking air, or too soft and not pressure-resistant." The product complies with the national standard GB/T 4622 is widely adapted for sealing flanges, valves, heat exchangers, pressure vessels, steam pipelines, and chemical piping. 

 II. Sealing principle of metal-jacketed gaskets Metaljacketed gaskets belong to elastic resilient sealing: 1. After bolt pre-tightening, the flexible graphite/PTFE filler is compressed, filling the tiny pits and scratches on flange sealing surface to achieve a tight seal; 2. The metal steel strip supports the overall structure, preventing the gasket from being flattened or extruded by high pressure; 3. the equipment experiences temperature rise, pressure rise, vibration, or thermal expansion and contraction, the gasket possesses good resilient compensation, always maintaining a tight fit and making it difficult for thermal relaxation to occur. Simply put: the metal ensures strength, the filler ensures sealing, and the resilience prevents leakage, which is the core reason for its durability and leak-proof performance

III. Common Material Combinations and Selection Differences Different material combinations correspond to completely different temperature, corrosion resistance, and pressure conditions, making selection critical. 1. Carbon Steel   Graphite Winding Gasket (Ordinary High-Temperature Conditions) Highest cost-performance ratio, good elasticity, and high-temperature resistance Suitable for thermal pipelines, steam pipelines, and ordinary boiler equipment. It is the most widely used model in power plants and heating engineering. 2. 304 Stainless Steel   Winding Gasket (Universal Best-Seller) Rust-proof, high-temperature resistant, and oxidation-resistant. Compatible with most oil, chemical, thermal, and municipal. Temperature resistance up to 450°C, offering the strongest versatility. 3. 316L Stainless Steel   Graphite Winding Gasket (Corrosion Upgrade) Acid and alkali resistant, corrosion resistant, and resistant to medium erosion. Suitable for corrosive chemical pipelines, sewage equipment, salt spray environments, and fine chemical plants. 4. Steel   PTFE Winding Gasket (Strong Corrosion, Pure White and Clean) PTFE-filled, resistant to strong acids and alkalis, and does not contaminate the medium Suitable for pharmaceutical, food, pure water, and strongly corrosive chemical conditions. IV. How to Choose Among the Four Structural Types? - Basic Type (No Ring): Mostly for raised-face flanges and small valves, low cost - With Inner Ring: Prevents gasket inward collapse and medium erosion, the preferred choice for high-pressure pipelines - Outer Ring: Precise positioning and prevents installation misalignment, universal for ordinary slip-on flanges - With Inner and Outer Rings: Positioning   anti-erosion   anti-extrusion, configuration for high-pressure, high-temperature, and pressure vessels

V. Core Advantages of Metal-Wound Gaskets 1. High temperature, high pressure, and thermal shock Operates stably in the range of -200°C to 450°C, unaffected by high-temperature steam or equipment thermal cycling, and will not age melt, or fail like rubber gaskets. 2. Excellent resilience, specifically designed to fix minor flange deformation and leakage Many old equipment flanges on-site have uneven surfaces or slight. Ordinary metal gaskets will inevitably leak, but wound gaskets rely on flexible resilience to automatically compensate for gaps, providing extremely strong sealing. 3. Vibration and fatigue resistance, suitable for-term continuous production Under working conditions with pipe vibration, pressure fluctuations, and frequent start-stop cycles, they are not easily loosened or cracked, with a service life far superior to gaskets. 4. Corrosion and rust resistance, wide range of applicable media Compatible with steam, water, oil, air, weak acids, weak alkalis, and chemical media suitable for the vast majority of industrial pipelines. 5. High installation tolerance, resistant to crushing The soft-hard combined structure ensures they are not too hard to compress like pure, nor easily crushed under high pressure like soft gaskets, offering extremely high stability.

VI. Main Application Scenarios Steam pipelines in power plants, heating networks, chemical plant, heat exchangers, pressure vessels, oil pipelines, gas pipelines, boiler equipment, valve flanges, sewage treatment equipment, food and pharmaceutical pipelines, hydraulic high-pressure equipment, etc. : As long as it is a flange interface that is high-temperature, pressurized, and requires long-term leak-free operation, metal-wound gaskets are basically used. . Common Misconceptions (Must-read for engineering) 1. Mixing new and old is not recommended: During maintenance, it is recommended to replace with new ones directly. compression resilience is already consumed, and old gaskets are prone to rework and leakage. 2. Excessive tightening is prohibited: Wound gaskets rely on resilience for sealing. Over-tightening collapse the graphite layer, actually causing air and water leaks. 3. Flange unevenness cannot be compensated: Flanges with severe corrosion or pitting must be repaired; otherwise, the best gaskets cannot maintain a long-term seal.

VIII. Summary The reason metal-wound gaskets have become the "evergreen" choice for industrial sealing lies in their principle: metal maintains the structure, filler ensures the seal, and resilience prevents leaks. They solve various on-site problems such as high temperature, high pressure, vibration, temperature difference and flange unevenness. With high cost-performance, wide applicability, and low replacement costs, they are the most reliable and universal sealing solution for industrial pipelines, pressure vessels, thermal chemical systems.