Valve Flange Connection: Is the flanges welded into the body of a valve?

In most designs, the flange is welded directly to the valve bodies; however, the flange and valve body can also be built as a single component.

Their flanged design provides several advantages, like consistent spreading of loads and increased simplicity of maintenance.

Our experience as a global custom flange valve manufacturer allowed us to comprehend crucial details such as valve flange connection and whether the flange is welded into the valve body.

So, continue reading as we’ll clarify the valve flange connection’s design, standards, dimensions, and so on.

What Is a Valve Flange Connection, and Is Its Flange Welded into the Body?

A valve flange connection is a common method for attaching a valve to a pipeline, utilizing circular flat discs with a central hole and surrounding bolt holes, known as flanges.

The pipe and valve flanges are aligned and fastened together with bolts and a gasket to create a tight, non-leaking seal.

The valve flanges may be built into the valve body itself (integral flanged).

It could also have a flange that is distinct from the valve body and joined to it by welding.

Differences Between Forged Integral Design and The Welded Flange Advantages 

A valve with flanges incorporated into the body has greater strength and fewer welds or seams that can weaken it and cause leaks.

Forged valves with integral flanges, in particular, operate longer and handle pressure, heat, and stress better because the valve and flange are produced together by heating, resulting in a continuous, strong structure.

On the other hand, welded flange valves have additional joints that can be potential weak spots because the flange and valve are not manufactured as a single unit. 

Furthermore, it is likely that they will have lesser mechanical strength at their welded joints, which could be problematic in high-pressure and stress applications. 

Integral flanged designs, notably forged ones, may be more expensive to build but provide long-term cost advantages by lowering maintenance requirements when in comparison to welded flanges.

Common Valve Flange Dimensions and Valve Flange Standards

Valve flanges have multiple dimensions to look out for, such as:

• Outside Diameter: the width of the entire flange measured from one edge to the other.
• Nominal Diameter: the size label of the pipe that the flange fits. Typically between DN15 (15 mm) and DN200 (200 mm).
• Bolt Hole Diameter: the size of the hole in which a bolt fits.

Furthermore, valve flanges also must comply with several standards, such as:

• EN 1092-1: for flanges with PN grades PN 2.5 to PN 400 and nominal sizes between 10 and 4000. 
• AWWA C207: Covering large steel flanges (4″ through 144″) beyond ASME B16.5 
• ASME B16.5: Addresses specific sizes for pipe flange and fitting dimensions of up to 24 inches in diameter.

CLDG: Your Trusted Partner For Forged Integral Gate Valve With Flange

Any flange valve encounters many issues.

For example, various studies, such as Ibai Coria et al., show that flange separation and external load, particularly around flanges, produce leaks due to thermal expansion and other factors.

As previously stated, integral flanged valves provide more benefits over welded designs when it comes to tackling these difficulties because their flanges are already connected. 

Furthermore, because CLDG prioritizes innovative solutions and client satisfaction, we have the capabilities to produce high-quality Forged Integral Flanged End Valve which further help address this with unique attributes, like:

• Meet many standards, including API 602, ASME B16.34, and ASME B16.10.
• Flanges are already part of the valve, preventing leaking weld joints, as well as buildup force and cracking.
• And so on.

Valve Flange Connection: In a nutshell

A valve flange connection is a connection between a valve and a pipeline utilizing round flat edges with bolt holes called “flanges.”

The flanges can be welded or integrated into the body, with the latter providing greater durability in more demanding situations.  

At CLDG, we use our decades of valve manufacturing knowledge to produce flanges that meet the strictest quality control requirements, including for oil and gas, and so on.
Request a sample or speak with our engineers to experience our quality firsthand!