1. Types and applications of reducing connection materials

1.Metal reducing joints

- Common materials: 16Mn steel, P11 steel.

- Features: High pressure bearing capacity, suitable for high temperature and high pressure environment.

- Limitations: Need to be welded for installation, sensitive to misalignment.

2.Rubber reducing joints

- Mainstream types:

- EPDM terpolymer: resistant to acid, alkali, ozone, and high temperature (-40℃~120℃), suitable for chemical and thermal pipelines.

- Chloroprene (CR): Excellent oil resistance, commonly used in petroleum transportation systems.

- Fluororubber (FKM): Resistant to concentrated acid/alkali and solvents, used in extreme corrosive environments.

- Structural design:

- Multi-layer reinforced cord fabric improves pressure resistance.

- Concentric reducing design balances pipeline deviation and absorbs vibration.

2. In-depth analysis of the causes of leakage in different-diameter pipelines

1.Welding defects and geometric stress concentration

- Misalignment problem: When the misalignment between the flange and the reducer reaches 9mm, a step is formed on the inner wall of the pipeline, which causes fluid turbulence and accelerates local erosion.

- Weld excess height: The residual excess height causes fluid reflux and continuously erodes the weld.

2.Electrochemical corrosion difference

- There is a potential difference between the weld metal and the 16Mn parent material, which forms galvanic corrosion in the CO₂ wet natural gas environment, and the weld dissolves first.

- Difference in corrosion product film: The product film in the weld area is loose and porous (easily eroded and peeled off), and the parent material area is dense and stable.

3.Assembly gap causes uniform corrosion

- The flange assembly gap allows the corrosive medium to penetrate, and the high-velocity area near the fluid side of the gap is mainly eroded, and the low-velocity area at the bottom is mainly chemically corroded.

4.Material and manufacturing defects

- Casting inclusions/folds, defects expanding into cracks during cold extrusion, and leakage during water pressure testing.

- Rubber joint cord layer delamination or rubber aging.

5.Flow-induced corrosion

- The turbulent kinetic energy at the point where the diameter of the reducer changes significantly increases, and the particle-carrying fluid (such as natural gas containing sand) aggravates wear.

6.Environmental and medium compatibility

- Wrong selection of rubber material: For example, nitrile rubber (NBR) swells and fails when in contact with concentrated acid.

- High temperature degradation: EPDM hardens and cracks in an environment of >120℃ for a long time.

3. Pipe repair clamp for reducing pipes

For reducing pipe leaks, as long as the two pipes are of different diameters, the connection part is due to various reasons, such as pipe aging and land subsidence, and the reducing connection part is detached over time, you can use the reducing pipe repair clamp for repair.

Reducing pipe repair clamp Repair scene 1

- Leakage at the bonding part of the plastic pipe, leakage at the bonding seam of the straight plastic pipe, leakage at the bonding seam of the bent plastic pipe, and leakage at the bonding seam of the tee of the plastic pipe. As shown in the figure below, there is a small difference in the outer diameter between the pipe and the fittings. There is a certain risk in using the general straight pipe repair clamp for repair. The best solution is to use the pipe repair clamp with different diameters of Baoshuo.

During the pipeline repair process, the maximum allowable outer diameter difference between the outer diameter of the pipe and the repair clamp is 3mm. If it is greater than this range, there is still a risk of successful installation.

Reducing pipe repair clamp Repair scene 2

  - Leakage at the connection points of pipes made of different materials. Due to engineering requirements, pipes of different materials are connected. In most cases, the outer diameters of the pipes are different. For example, the connection between the cement pipe and the steel pipe in the figure has different outer diameters. Due to land subsidence and other reasons, there is a risk of the pipes coming off. It is necessary to carry out the expected fixed prevention treatment. When repairing leakage at the connection points of pipes of different materials, it is recommended to use a different-diameter pipe repair clamp。

Reducing pipe repair clamp Repair scene 3

For leaks in reducers and reducers in various application scenarios, it is also a common repair method to wrap the entire reducer. Baoshuo Pipe Fittings specializes in solving various pipeline problems.

PVC pipe fittings with different diameters leaking	PVC pipe fittings bonding reducer leakage	PE pipe fittings with different diameters leaking
Electric fusion and hot fusion pipe fittings with different diameters leaking	Flange-connected reducer leaks	Flange connection reducer leakage