Fluid Power World

  • Home
  • Technologies
    • Hydraulics
      • Cylinders & Actuators
      • Filtration/Contamination Control
      • Fittings, Couplings & Adapters
      • Fluids
      • Fluid Conditioning
      • Hose & Tubing
      • Pumps & Motors
      • Related Technologies
      • Sealing
      • Sensors & Gauges
      • Valves & Manifolds
    • Pneumatics
      • Air Preparation & Regulation
      • Compressed Air Technologies
      • Cylinders & Actuators
      • End Effectors & Grippers
      • Fittings, Couplings & Adapters
      • Hose & Tubing
      • Sensors
      • Vacuum
      • Valves & Manifolds
  • Engineering Basics
  • Trending
  • Resources
    • Digital Issues
    • Pneumatics Tech Toolbox
    • Podcasts
    • Subscribe to Fluid Power World Print Magazine
    • Videos
    • Webinars / Digital Events
    • White Papers
  • Women in Engineering
    • Women in Fluid Power
    • Women in Engineering
  • Design Guide Library
  • Classrooms
    • Pneumatics Classroom
  • SUBSCRIBE

When should you use welded or bolted flange connection systems?

By Mary Gannon | December 6, 2024

Share

By Josh Cosford, Contributing Editor

There are three ways to plumb a hydraulic system — rigid systems, flexible systems or a combination of the two. Rigid systems include pipe and various forms of tube, while flexible systems are assembled using only hydraulic hose. Most machines today are created using a combination of fixed plumbing, where no movement needs to occur, and flexible plumbing (hoses), where bending and flexibility are required.

hydraulic flanges AdobeStock_444610770

A common form of fluid connection for modern hydraulics is the flange. These are available in a few international standards, and what you use will depend on where you live. The SAE J518 style is commonly used in North America in their Code 61 and Code 62 variations. And if you’re in other parts of the world, those standards could be ISO 6164, CETOP or JIS B 2291.

No matter the standard, they’re all a great way to connect plumbing to your pumps, cylinders, motors, valves and manifolds. There is no need to twist or turn the hose or tube to tighten the connection, as is required with other connection threads such as NPT or BSPP. For a flange, you only need to place the flange against the port, install four bolts, and tighten it to spec.

A welded flange is machined with a conical bevel to provide a pocket for the weld bead to reside. Without this bevel, a butt weld would offer little to no strength, especially at high pressure. When installing permanent plumbing, the flange is first bolted in place, and then the terminating end of the tube, which also has a bevel, is tack welded into place to be completed later. If you’re sure the final tube assembly sits as it will for its final iteration, the tube may be welded to the flange entirely. Just remember to do so without the flange O-ring installed.

A welded flange can be used to connect manifolds, junctions or inline joints, as well as for the ports of components. Realistically, and especially for industrial installations, fixed plumbing may be suitable for an entire machine. Many industrial machines have no pivoting joints that require a hose, and the result is a permanent solution with little to no maintenance required.

A bolted flange is one where an intermediate connection must be used to join the plumbing to the port. The flange will be thicker than weld flanges, as there must be enough depth to allow a port to be drilled and tapped into it. The port can be of any traditionally available to hydraulics, such as NPT, ORB, BSPP, or metric. Those female ports will then employ an adapter of some sort to provide the actual plumbing connection, which, again, may be tube or hose.

The JIC male adapter installed into the flange makes a popular choice, mainly because of the ease of installing a female hose that ends with a swivel. One of the various tube connections that uses ferrules or other locking devices makes a semi-permanent connection nearly as rigid as a weld connection.

Whether welded or bolted, the flange connection is growing in popularity due to its ease of installation, strength of connection and simple maintenance requirements. If you’re plumbing your system from scratch, a solid plan using welded flanges provides
the best long-term solution. However, upgrades or rebuilds might benefit from the flexibility of bolted flange connections.


Filed Under: Components Oil Coolers, Engineering Basics, Featured, Fittings, Couplings & Adapters, Hose Assembly Tips

 

About The Author

Mary Gannon

Mary Gannon is editor of Fluid Power World. She has been a technical writer and editor for more than 13 years, having covered fluid power, motion control and interconnect technologies.

Current Digital Issue

  Easier access to more of our content Every other month, readers of Fluid Power World have access to our beautiful print and digital editions, where we share a selection of the best fundamentals content, technology news, case studies, and technical articles that cover the gamut of hydraulics and pneumatics system design. But we only…

Subscribe!

Fluid Power World is written by engineers for engineers engaged in designing machines and or equipment in Off-Highway, Oil & Gas, Mining, Packaging, Industrial Applications, Agriculture, Construction, Forestry, Medical and Material Handling. Fluid Power World covers pneumatics, mobile hydraulics and industrial hydraulics.

Fluid Power Design Guides

fluid
“fpw
EXPAND YOUR KNOWLEDGE AND STAY CONNECTED
Get the latest info on technologies, tools and strategies for Fluid Power Professionals.

RSS Featured White Papers

  • Moving fluid power forward
  • High-force linear motion: How to convert from hydraulic cylinders to electric actuators and why.
  • A technical comparison: Performance of pneumatic cylinders and electric rod actuators
Fluid Power World
  • Hose Assembly Tips
  • Mobile Hydraulic Tips
  • Pneumatic Tips
  • Sealing & Contamination Control Tips
  • About us
  • Contact Us

Copyright © 2024 WTWH Media LLC. All Rights Reserved. The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of WTWH Media
Privacy Policy | Advertising | About Us

Search Fluid Power World

  • Home
  • Technologies
    • Hydraulics
      • Cylinders & Actuators
      • Filtration/Contamination Control
      • Fittings, Couplings & Adapters
      • Fluids
      • Fluid Conditioning
      • Hose & Tubing
      • Pumps & Motors
      • Related Technologies
      • Sealing
      • Sensors & Gauges
      • Valves & Manifolds
    • Pneumatics
      • Air Preparation & Regulation
      • Compressed Air Technologies
      • Cylinders & Actuators
      • End Effectors & Grippers
      • Fittings, Couplings & Adapters
      • Hose & Tubing
      • Sensors
      • Vacuum
      • Valves & Manifolds
  • Engineering Basics
  • Trending
  • Resources
    • Digital Issues
    • Pneumatics Tech Toolbox
    • Podcasts
    • Subscribe to Fluid Power World Print Magazine
    • Videos
    • Webinars / Digital Events
    • White Papers
  • Women in Engineering
    • Women in Fluid Power
    • Women in Engineering
  • Design Guide Library
  • Classrooms
    • Pneumatics Classroom
  • SUBSCRIBE