Application Characteristics of Laser Cladding in the Repair of Small and Medium-Diameter Pipeline Inner Walls

With the increasing advancement of technology, laser cladding technology has matured and is now widely applied in manufacturing industries such as shipbuilding, petroleum, and mining. These industries require a large number of pipelines, and the inner walls of these pipelines are subject to varying degrees of wear during use, affecting their performance and lifespan. Therefore, enhancing the wear resistance and corrosion resistance of pipeline inner walls is key to addressing this issue.

As a new material surface modification technology, laser cladding involves placing selected coating materials on the surface of a substrate with different fillers and using laser irradiation to simultaneously shape and melt them with the substrate surface. The rapid solidification forms a thin layer on the substrate, creating a metallurgically bonded surface coating that significantly improves the substrate's wear resistance, corrosion resistance, heat resistance, oxidation resistance, and other properties.

Characteristics of Laser Cladding Repair Technology:

1. Ultra-fast melting speed (10³～10⁶°C/s), high processing efficiency, and fast processing speed;

2. The cladding layer forms a strong metallurgical bond with the substrate, with a dense structure, small heat-affected zone, and low dilution rate;

3. A wide selection of cladding materials allows for different designs based on engineering requirements, enabling effective control of the cladding layer's structure and properties during the process;

4. Laser cladding is a precision processing method that enables localized processing of small areas. The process does not involve direct contact with the parts, avoiding contact damage to components, and is easily automated. This technology was initially used for pipeline cladding.

Currently, laser cladding technology can only be applied to large-diameter pipelines. For medium and small-diameter pipelines, cladding is primarily limited by spatial constraints, making it difficult for the laser head to enter the pipeline. The process is complex and costly, with traditional laser cladding heads having a long focal length, low processing efficiency, and susceptibility to damage to protective lenses, making it challenging to achieve good processing quality.

The application requirements for inner wall cladding and repair of high-load components are continuously increasing, with expectations for excellent wear resistance, erosion resistance, corrosion resistance, and other properties, such as in bearings, molds, cylinders, oil cylinders, extrusion cylinders, valves, etc. As product performance and structural complexity increase, the industry demands higher applicability, scalability, versatility, and efficiency for inner wall laser cladding repair technology.

Unlike outer wall laser cladding, inner wall laser cladding requires the laser beam, powder, and cooling water to be delivered over a long distance through a limited space to the optical head. For processing, the inner wall laser cladding head must feature high integration, high precision, and high rigidity.

Xi'an Guosheng Laser Technology Co., Ltd.'s inner wall laser processing system is designed with application convenience in mind. The system adopts a modular design, allowing for integrated inner and outer wall laser cladding through different motion forms of the machine tool and robot. Meanwhile, based on different product characteristics and process requirements, supporting process specifications for various methods such as laser cladding, repair, and inner wall hardening have been developed.

Advantages of Laser Cladding Repair Technology:

1. High integration and stability: Powder, gas, water, and optical paths are all integrated within the tube.

2. Minimum applicable pipeline inner diameter: Ф85mm.

3. Maximum extension length: 3mm on one side.

4. Suitable for blind hole processing: Powder flow and 45° oblique incidence beam design.

5. Multi-functional quick switching: Replace the front nozzle to complete cladding, metal addition, welding, quenching, and other processes.

6. Applicable to various materials: Can prepare alloy coatings such as iron-based, nickel-based, cobalt-based, copper-based, and composite materials.