Introduction

Reducer welding neck flange is a type of flange used to connect different pipe sizes, and in addition, reducing pipes can also be used. But this article will mainly introduce the product of reduced diameter welded neck flange. What are the meanings and characteristics of this specification of flange, and what are its other uses besides connecting pipes of different sizes?

What Is a Reducing Weld Neck Flange?

The reducing welding flange has a longer conical hub, and its end port diameter can be customized according to the needs to accommodate pipes of different diameters connected. This type of flange is not a conventional flange, but a customized flange. Generally, customers are required to provide drawings. This type of flange is generally used in industrial pipelines such as oil and gas, and can be made into higher pressure ratings as needed.

Why Are Reducing Weld Neck Flanges Used?

Reducing welding neck flange is equivalent to the combination of reducing pipe and flange, which can reduce the installation process between pipes of different diameters. No need for construction personnel to weld multiple times. Simplified installation of accessories while also saving installation space. But it will not affect the smoothness of pipeline size.

It is widely used in some refineries and offshore projects. Because it can reduce the installation steps and simplify the installation layout. Effectively improve the completion time of the project.

How Do You Specify a Reducing Weld Neck Flange?

When purchasing a reducing butt welded flange, the following points need to be considered:

• The large-diameter size of the steel pipe is consistent with the flange diameter.
• The small diameter of the steel pipe is consistent with the reduced diameter of the welded flange.
• The pressure rating needs to be selected according to the requirements of the pipeline system, commonly including ASME B16.5 standard 150 and 300.
• The wall thickness specification of the flange needs to be consistent with the wall thickness of the steel pipe.
• The material also needs to be the same as the pipe fitting material, commonly including carbon steel, stainless steel, and alloy steel.

What Are the Advantages of a Reducing Weld Neck Flange?

• Reduce welding – only need to weld the tapered hub of the flange.
• High strength – The long conical hub can reduce the stress at the connection point.
• Welding safety – In high-pressure pipeline systems, reducing welding points can also make the entire pipeline safer.
• Space saving – can be used in some compact piping systems.
• Diverse sizes – as it is a customized product, different sizes can be made according to customer drawings.

Where Are Reducing Weld Neck Flanges Commonly Used?

Reducing butt welding flanges are widely used, with many of them being applied in the industrial pipeline industry.

• Oil and gas industry: used for high-pressure pipeline transportation.
• Power plant: used to connect steam pipes and turbines.
• Chemical plant: In the transportation of corrosive products, this high safety reducing butt welding flange is required at the connection.
• Shipbuilding industry: used for connecting pipeline systems in large ships.
• Pipeline: Pipeline systems in various industries, as long as they are needed by designers.

Reducing Weld Neck Flange Dimensions (PDF Reference)

In addition to the pictures provided by the customer, there are also some more conventional size tables for reduced diameter welding flanges. This size chart specifies the following aspects:
outer diameter

• bolt circle diameter
• Number and size of bolt holes
• Wheel size
• inner hole size

If more detailed data is needed, please refer to the PDF document of the reduced diameter butt welding flange dimensions. Or search the ASME B16.5 official website for more information.

Reducing Flange vs Slip-On Reducing Flange

The appearance of reduced diameter butt welding flanges and reduced diameter flat welding flanges may be similar, but their specific uses are different:

• Reducing Weld Neck Flange: Suitable for high-strength, high-pressure pipeline systems.
• Slip On Reducing Flange: Suitable for medium to low pressure pipeline systems.

For those who are new to this industry, the safest option is to choose slip on flange for medium and low-pressure systems, and welding neck flange for high-pressure systems.

Reducing Flange Standards and Charts

Shrinkage flanges also need to comply with industry standards, among which the most commonly used standards are the following three:

• ASME B 16.5: Sizes typically range from 1/2 inch to 24 inches.
• ASME/ANSI B16.47: This standard is mostly for large diameters, i.e. 60 inches and above.
• DIN, JIS, EN: These are standards from different countries, with calibers ranging from 1/2 inch to 24 inches.

Reducing Flange Threaded and Other Types

In addition to reducing butt welding flanges, there are other types of flanges:

• Threaded Reducing Flange: No need for welding installation, can be installed by tightening, and is commonly used in low-pressure small-diameter pipeline systems.
• Slip On Reducing Flange: Used for medium and low pressure piping systems, with a lower price.
• Blind flange: used for sealing pipeline systems.

Each type of flange has its own production standards and pressure rating.

Summary

The reduced diameter flange in this article is mainly used to connect pipes and steel pipes with different diameters at both ends. This type of connection is similar to that of a reducer and a butt welded flange, but it is safer than this type of connection. This type of flange is also commonly used in high-pressure pipeline systems. Or some connections that come into contact with high temperatures.

The production of reduced diameter butt welded flanges also needs to follow the production standards of flanges, such as ASME B16.5, ANSI, JIS, DIN or EN.