What is a concentric reducer?

The primary structural feature of a concentric reducer is its concentric design. This structure ensures that the flow direction of the fluid remains unchanged as it passes through the reducer, maintaining a relatively stable flow state. The characteristic of a concentric reducer lies in the fact that the centerlines of its two ends (the larger and smaller openings) are perfectly aligned. When viewed from the side, it exhibits a symmetrical conical structure, resembling a bell or funnel. This design ensures smooth fluid transition within the pipeline, minimizing the generation of vortices and turbulence, making it particularly suitable for applications with stringent requirements for fluid flow.

Differences Between Concentric and Eccentric Reducers

The primary difference between concentric reducers and eccentric reducers lies in the position of the centerlines at both ends: the centerlines of a concentric reducer are aligned on the same straight line, forming a symmetrical conical shape, suitable for vertical pipes or applications requiring high fluid symmetry; whereas the centerlines of an eccentric reducer are not aligned on the same straight line, with one side transitioning in a straight line, commonly used in horizontal pipes to prevent gas accumulation or liquid stagnation.

Concentric Reducer Specification

Features of Stainless Steel Concentric Reducers

High Corrosion Resistance: The composition of stainless steel makes it resistant to corrosion from a wide range of chemical media, making it ideal for use in industries such as the chemical, petroleum, and food processing.

Hygienic and Non-Toxic: The smooth surface resists bacterial growth and is easy to clean, meeting food-grade and sanitary standards.

High Strength and Durability: Withstands high pressures and temperatures for a long service life.

Excellent Weldability: Easily welds to stainless steel pipes, creating a tightly sealed piping system.

Concentric Reducer Weight Calculation Formula

The steel pipe reducer weight formula is 0.02466 * S <(D+d)/2 – S> * H / 1000
D = Large end diameter in mm.
d = Small end diameter in mm.
S = Large end Thickness in mm.
H = Height from end to end.

If we want to calculate the weight by formula, we need to know above 4 factors. Where can you get them? Usually we get the them from pipe reducer dimensions.

ASME B16.9 Concentric Reducer Dimension

ASME B16.9 Concentric Reducer Weight

Stainless Steel Concentric Reducer Manufacturing Process:

1. Hot Rolling (Extruded Seamless Steel Tubing): Round tube blank → Heating → Piercing → Three-roll oblique rolling, continuous rolling, or extrusion → De-burring → Sizing (or reducing diameter) → Cooling → Straightening → Hydrostatic testing (or non-destructive testing) → Marking → Storage

Hot rolling is a processing method performed above the recrystallization temperature of the metal material. For stainless steel, this typically means temperatures exceeding 1000°C. The stainless steel tube blank is heated to high temperatures and then repeatedly rolled through rollers to reduce its diameter and thin its wall thickness, ultimately forming the desired-sized tubing.

2. Cold drawing (rolling) seamless steel tubes: Round tube blank → Heating → Piercing → Heading → Annealing → Acid washing → Oil coating (copper plating) → Multiple cold drawing (cold rolling) → Blank tube → Heat treatment → Straightening → Hydrostatic testing (inspection) → Marking → Storage.

Cold drawing is performed below the recrystallization temperature, typically at room temperature. Using hot-rolled tubes as raw material, the tubes are drawn through a die to further reduce their diameter and wall thickness. To ensure smooth drawing operations, annealing is typically performed between drawing intervals.

How to make a reducer？

Reducers are pipe fittings designed to meet pipe diameter requirements. Common forming processes include reducing/expanding, or both. Stamping can also be used for certain reducer sizes.

a. Reducing/Expanding Forming

The reducing/expanding forming process involves placing a tube blank of the same diameter as the larger end of the reducer into a die. Pressing is performed along the tube blank’s axial direction, causing the metal to move along the die cavity and shrink. Depending on the size of the reduced diameter, this process can be performed in a single press or multiple presses.

b. Stamping

In addition to using steel pipe as raw material to produce reducers, some sizes can also be produced using steel plate using a stamping process. The die used for drawing is designed based on the reducer’s inner surface dimensions. The blanked steel plate is then stamped and stretched using the die.

Common Applications

Chemical and petrochemical industries

Food and beverage processing

Pharmaceutical industry

Water treatment and desalination

Oil and gas transportation

Pulp and paper and sugar industries

Marine and offshore engineering

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304H Threaded Bushing are generally processed by cutting and forging a hexagonal rod, and uses a wide variety of thread types. It is an internal and external threaded fittings and used to combine two different diameter pipes. So has an irreplaceable place in the pipeline connection.

Hex Head Bushing

Flush Bushing

Flush Bushing is the type without head and Hex Head Bushing is the general type. They are ASME B16.11 Threaded Fittings and available in stainless steel, carbon steel and alloy steel.

Hex Head Bushing Dimensions

Hex Head Bushing Dimensions

Normally they are not identified by class. They may be used for ratings up to class 6000.

Hex Head Bushing Weight in kg

Stainless Steel F304H Pipe Fittings

It is an austenitic chromium-nickel steel alloy and the greater carbon content delivers an increased tensile and yield strength. Both short term tensile strengths and long term creep strengths are higher for these high carbon grades.

They have good corrosion resistance to atmospheric and many organic and inorganic chemicals, and can be used in foods and beverages industries. The austenitic structure also gives these grades excellent toughness, even down to cryogenic temperatures.

Our SS 304H Threaded Bushing are used for a wide variety of home and commercial applications with excellent corrosion resistance, high ease of fabrication, outstanding formability, and tremendous strength.

A182 304H Threaded Bushing Chemical composition %

A182 304H Threaded Bushing  Mechanical Properties

304H Stainless Steel  Equivalent Grades

SS316H Fittings

SS316H Fittings

It is versatile in application and can be the material of wrought Butt Weld Fittings and Forged Socket Weld Fittings and Threaded Fittings.

SS316H Pipe Fittings that our company can provide are Butt Weld 90 Degree Elbow, Socket Weld Full Coupling, Threaded Half Coupling, Butt Weld Eccentric Reducer, Threaded Nipple, Socket Weld Reducing Tee, Weldolet, Sockolet, Threadolet, Threaded Plug.

Usually Stainless Steel Fittings are used in Petrochemicals, Oil & Natural Gas Organization, Fats, Fertilizers, Sugar Mills & Distilleries, Cement Industries, Ship Builders, Paper Industries, Pumps, Automation, Paints, Steel Industries, etc.

Solution Treatment of 304H Threaded Bushing

It plays a vital role in the quality and safety of pipe fittings. It is necessary for stainless steel fittings to adopt solution treatment to enhance the safety.

Austenitic stainless steel is softened by heat treatment and heated to about 950-1150 degrees, and keep the temperature for a certain period of time, so that carbides and various alloying elements are uniformly dissolved in austenite.

The metal molecular structure, magnetic properties and physical properties have changed after Stainless Steel Fittings processing. It can restore the corrosion resistance that is affected after processing, and at the same time obtain the hardness required for the stainless steel, to ensure the performance of pipe fittings.

Solution Treatment of Stainless Steel

Three Element of Solution Treatment

They have a great influence on the corrosion resistance and appearance brightness of stainless steel, and play a decisive role in the processing properties of stainless steel.

1.Temperature

The temperature should reach 950-1150 degrees Celsius to have a softening effect, and the hardness can be reduced to less than 220 HV. If the temperature is not properly controlled, various quality defects are prone to occur.

2. Time

During the heating process, the residual ferrite content decreases as the heating time increases.

3. Heat Rate and Preservation        

Since the stainless steel has a low thermal conductivity, so the heating process should be slow. If the heating rate is too fast, deformation is likely to occur.

The whole process takes about 40 minutes.

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Manufacturer of stainless steel pipe fittings not only consider cost of pipe fittings, but consider corrosion prevention and product quality. Therefore, stainless steel pipe will take the solid solution in the manufacturing, because it enhance the safety of pipe fittings. The Stainless Steel Treatment is very important for the quality and safety of the pipe. There are small number of manufacturers in order to save costs. It will bring permanent troubles in future that changes solid solution to polished sand blasting for the purpose of covering defects.

The solution treatment is the stainless steel heated to 950~1150℃, then preservation the temperature for a certain time. This process makes carbide and various alloying elements evenly dissolved,  Austenitic stainless steel are soften.

A403 WP304 Conc Reducer

Stainless Steel Heat Treatment Effect 

After forming and welding of the stainless steel pipe, the structure, magnetism and physical properties of the metal have changed. The solution process can restore the corrosion resistance after processing, and obtain the hardness of stainless steel to ensure the best performance. After the solution treatment of stainless steel pipe fittings, has a good role in improving:

1. Make pipe fittings more convenient and safe in the installation. It eliminates modification phenomenon of Stainless Steel Pipe Fittings, so that the hardness reduced to 220HV below, and improves plasticity and toughness as well.

2. Restoring the stress and intergranular change of stainless steel pipe fittings in the process, reduce stainless steel intergranular corrosion and stress corrosion, enhance corrosion resistance.

3. Removing magnetic, stable austenite organization of stainless steel due to processing.

4. Restoring the surface natural brightness of the stainless steel material (natural bright and polished light is different).

Characteristics of Stainless Steel Pipe Fittings Solid Solution

Stainless steel is a special steel, since nickel, chromium and other alloying elements exist. So it has different characteristics with ordinary steel heat treatment.

1. The thermal conductivity of stainless steel is low, so heating process at low temperature should be slow. At room temperature, stainless steel  only has 27% of carbon, and with the increases of heating temperature, the thermal conductivity characteristics and difference decreases gradually.

2. Austenitic stainless steel is get to 1100 ℃ by solution heating, can inhibit the production of carbide, and then quickly cooled to room temperature, so that carbon reached over saturation, can greatly improve corrosion resistance of stainless steel.

3. Pipe fittings are using (hydrogen) gas protection in the solution process, to avoid stainless steel surface viscous iron oxide production, Restoring stainless steel surface,and improving the appearance of the reputation.

Three Elements for Solid Solution Stainless Steel Pipe Fittings

The advantages and disadvantages of solution process have a great influence on the corrosion resistance and the appearance brightness of stainless steel, and it plays a decisive role in the processing performance. Therefore, the heat treatment has play a important position s in the production of stainless steel pipe fittings

1.Solution temperature. According to the characteristics of stainless steel chemical composition, solution temperature of 950-1150 degrees to achieve softening effect, so that the hardness of stainless steel reduced to 220HV, to meet the quality requirements of pipe installation. If the temperature control is unreasonable, it is easy to appear various quality defects.

2. Solution time. The residual ferrite content of austenitic stainless steels decreases with heating time increasing in the heating process. Therefore, the solution treatment should at 1050 ℃. So that the carbon reaches saturation, improve corrosion resistance. And then quickly cooled in the air to achieve the solution effect.

3. The heating process of stainless steel at low temperature should be slow. If the heating speed is too fast to produce deformation,so should be controlled heating speed, and pay attention to heat preservation time. such as 316L in 1100 ℃, residual ferrite content will continue to be reduced if holding time long.

The solution of stainless steel pipe fittings should be heated–insulation–time cooling process, it will take about 40 minutes.

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