Flange bolting plays a critical role in ensuring the integrity of piping systems. Improper installation is the most common cause of leaking joints, which can lead to costly downtime, safety risks, and operational inefficiencies. At Sunjin Metals Vina (SJM Vina), we provide Korean-origin steel pipes, flanges, and fittings for industrial projects, and we emphasize that proper flange bolting procedures must always be followed. Below is a comprehensive guide to the correct procedure for flange bolting.
1. Cutting of Soft Gaskets
-
Punch or cut bolt holes slightly larger than the bolts to ensure proper seating.
-
Never cut a gasket by hammering against the flange surface.
-
Always use a proper gasket cutter to achieve the exact size.
-
Ensure the inside diameter of the gasket is not smaller than the inside diameter of the pipeline to prevent flow obstruction.
2. Handling of Gaskets
-
Carry and store gaskets carefully to avoid bending or damaging them.
-
Large-diameter metallic and semi-metallic gaskets should be transported with proper packing or mounting boards.
3. Tools and Cleaning
-
Clean flange surfaces and fasteners thoroughly before installation.
-
Use wire brushes or brass scrapers to remove debris, rust, or gasket residue.
-
Flange spreaders may be required to open gaps for cleaning.
-
Ensure all torque wrenches and tensioning tools are properly calibrated.
4. Visual Inspection
-
Inspect bolts, nuts, and washers for cracks, burrs, or other defects.
-
Check flange faces for warping or scoring to confirm flatness and parallelism.
-
Ensure the correct gasket type, size, and thickness is selected and is free from damage.
5. Lubrication
-
Apply suitable lubricant (oil and graphite mix recommended) to fastener threads, nut bearing surfaces, and washers.
-
Proper lubrication reduces friction and ensures even distribution of bolt load.
-
Avoid contaminating gasket or flange faces with lubricant.
6. Gasket Installation
-
Place the gasket carefully between flanges and ensure it is centered.
-
Do not use tape, jointing compounds, or release agents.
-
If temporary fixing is needed, use a light spray adhesive.
7. Bolt Tightening Sequence
Achieving correct bolt load is essential: low enough to avoid gasket damage, but high enough to ensure sealing.
-
Always use a torque wrench or controlled-tensioning device.
-
Tighten bolts using the cross-bolting pattern in multiple passes:
-
Pass 1: Hand-tighten bolts in cross pattern.
-
Pass 2: Torque to ~30% of final value.
-
Pass 3: Torque to ~60%.
-
Pass 4: Torque to 100%.
-
Pass 5: Repeat at full torque, clockwise around the flange.
-
Repeat the final pass until no further nut movement is observed. Hydraulic tensioners or heating methods may also be used for large bolts.
8. Re-Tightening
-
Due to material relaxation, bolts may require re-tightening after 24 hours at ambient temperature.
-
Do not re-torque elastomer-based asbestos-free gaskets after exposure to high temperatures, as embrittlement may occur.
9. Storage of Gaskets
-
Store gaskets flat, in a cool and dry place, away from sunlight, water, and chemicals.
-
Avoid hanging soft gaskets as they may deform.
-
Graphite and PTFE gaskets have an almost indefinite shelf life, but elastomer-based gaskets should not be used after 5 years.
10. Additional Technical Considerations
-
Flange Insulation Sets: Installed to prevent electrical current flow in pipelines.
-
Direct Tension Indicators (DTI): Provide visual proof of correct bolt load.
-
Gasket Reuse: Reusing gaskets is not recommended as sealing ability is compromised.
-
Spacer Rings: Recommended instead of stacking multiple gaskets to fill gaps.
-
Hydrostatic Testing: Requires higher bolt stresses and sometimes high-strength alloy bolts.
11. Common Wrong Practices
Avoid the following:
-
Reusing old gaskets.
-
Storing gasket sheets vertically.
-
Cleaning flanges with chisels or saw blades.
-
Cutting gaskets by hammering against flanges.
-
Using multiple gaskets to fill gaps.
-
Applying grease on gasket faces.
-
Using ordinary or rusted fasteners without lubrication.
-
Incorrect tightening sequence.
Conclusion
Correct flange bolting procedures are essential for safe, leak-free, and efficient piping systems. By following proper steps in gasket handling, flange cleaning, bolt tightening, and inspection, the risk of leaks and costly maintenance is significantly reduced.
At Sunjin Metals Vina (SJM Vina), we are committed to providing high-quality steel pipes, flanges, and fittings of Korean origin that meet international standards. Our expertise ensures that industrial clients receive not only reliable products but also technical guidance for optimal performance.
📍 Sunjin Metals Vina (SJM Vina)
628 Le Hong Phong, Ward 10, District 10, Ho Chi Minh City, Vietnam
📞 Hotline: +84 33 4233 127
📧 Email: sjmvina@sunjinmetal.com
🌐 Website: www.sjmvina.com.vn
Views: 18
In industrial piping systems, flanges play a critical role by securely connecting pipes, valves, pumps, and other equipment. They ensure tight sealing, mechanical stability, and easy disassembly for maintenance.
To guarantee proper identification and compliance with international standards, every flange is marked with detailed information, including standard, pressure rating, material, and manufacturing data. These markings are not just identification codes – they are essential for quality control, traceability, and system safety.
In modern hydraulic systems, where fluids are transmitted under extreme pressure, every component plays a vital role in ensuring overall performance and safety. Among these components, steel flanges are indispensable. They are used to connect pipes, valves, pumps, and other equipment, creating a secure and leak-proof joint that withstands both high pressure and temperature.
Today, Korean steel flanges have gained strong recognition in the industrial market thanks to their superior quality, durability, and compliance with strict international standards. Their exceptional ability to endure high pressure makes them an ideal solution for hydraulic systems and other demanding industrial applications.
In industries operating in marine and coastal environments, the durability and resistance of materials to corrosion are critical factors in ensuring safety and long-term performance. Among the most essential components in pipeline systems for marine applications are steel flanges, which connect pipes, valves, and fittings. For environments exposed to seawater, Korean steel flanges have proven to be an optimal solution due to their superior quality, corrosion resistance, and compliance with international standards.
In modern industries, pipeline systems are required to operate under increasingly complex and demanding conditions. From oil and gas, petrochemicals, power plants, to marine engineering, the performance and safety of pipeline connections play a critical role in ensuring stability and minimizing risks. Among the essential components of these systems, Korean steel flanges stand out for their superior leak-proof properties in high-pressure environments, helping businesses optimize operations while ensuring compliance with safety standards.
In industrial systems, especially in the oil and gas, energy, chemical, and construction sectors, steel flanges play a vital role in connecting pipelines, equipment, and valves. To ensure safety and operational efficiency, flange products must strictly comply with national and international quality standards. Among these, the KS (Korean Standards) system stands out as a benchmark widely applied to Korean steel flanges, ensuring stability, safety, and long-term durability.
In industrial systems, boilers play a crucial role in generating steam, heat, and energy for various production processes. These systems operate under extreme conditions, including high temperatures, elevated pressure, and long continuous working hours. Therefore, all piping materials and connection components must meet strict standards of strength, durability, and safety.
In industrial piping systems, pipe fittings play a vital role in connecting pipelines, changing flow direction, branching, or adjusting pressure. To ensure safety, efficiency, and durability, these fittings must comply with strict international and regional standards. Among them, KS (Korean Standards), JIS (Japanese Industrial Standards), and ASTM (American Society for Testing and Materials) are the three most recognized systems applied to Korean pipe fittings.
At Sunjin Metals Vina (SJM Vina), we specialize in supplying Korean steel pipes, Korean steel flanges, and Korean pipe fittings, all manufactured in compliance with these standards to serve key industries such as oil & gas, chemical processing, power generation, and construction.
In the oil & gas sector, steel pipes and pipeline accessories form the foundation of safe, durable, and efficient pipeline systems. Among them, Korean steel flanges are highly valued for their superior quality, precise manufacturing, and ability to meet stringent international standards.
At Sunjin Metals Vina (SJM Vina), we specialize in supplying Korean steel pipes, Korean steel flanges, and Korean pipe fittings, serving industrial projects, especially in the oil & gas industry, with a strong commitment to quality and professional service.
In industrial construction, steel pipes play a vital role in creating durable, stable, and safe structural systems for large-scale projects. With outstanding advantages in quality, load-bearing capacity, and durability in harsh environments, Korean steel pipes have increasingly become the preferred choice for contractors and investors in Vietnam.
At Sunjin Metals Vina (SJM Vina), we specialize in supplying Korean steel pipes, Korean steel flanges, and Korean pipe fittings that fully comply with international standards, providing optimal solutions for industrial construction projects.
In the oil and gas industry, piping systems must operate under extreme conditions with high pressure, fluctuating temperatures, and corrosive environments. To ensure safety and efficiency, high-pressure Korean pipe fittings are considered the optimal choice thanks to superior quality, strict international standards, and long-term reliability.
At Sunjin Metals Vina (SJM Vina), we specialize in supplying Korean steel pipes, Korean steel flanges, and Korean pipe fittings that meet the most demanding requirements of onshore and offshore oil and gas projects.
In modern industries such as oil & gas, petrochemical, power generation, and shipbuilding, Korean steel flanges, pipes, and fittings are trusted for their high precision, durability, and compliance with international standards. Among them, the production technology of Korean steel flanges plays a decisive role in ensuring product quality and operational safety.
At Sunjin Metals Vina (SJM Vina), we specialize in supplying Korean-origin steel pipes, flanges, and fittings, manufactured under strict technological processes that meet global requirements. In this article, we will provide an in-depth look at two primary production methods of steel flanges: forging and casting, highlighting their characteristics and advantages.
Pipe Pressure Calculator (Công cụ tính áp suất ống)
Steel Pipe Weight Calculator
Pipe Wall Thickness Calculator (ASME B31.3)
ASTM A105/A105M is a critical standard issued by the American Society for Testing and Materials (ASTM), specifying requirements for forged carbon steel used in the manufacture of pipe flanges, valves, fittings, and other high-pressure components. Known for its excellent mechanical properties and cost-effectiveness, this material is widely used in industries such as oil and gas, chemical, power, and construction. This article provides a detailed overview of the ASTM A105 standard, covering its chemical composition, mechanical properties, manufacturing processes, applications, and key considerations for material selection, assisting engineers, procurement managers, and project professionals in making informed decisions.
Sunjin Metals Vina (SJM Vina) is a trusted supplier of steel pipes, flanges, and fittings sourced from South Korea and other countries, ensuring compliance with international standards.
