Recently, the metal 3D printing R&D team at the Shougang Research Institute of Technology and the engineering manufacturing team at Beijing Shougang Machinery and Electric Co., Ltd. have successfully applied metal 3D printing remanufacturing technology to the window surface repair of a rolling mill, which forms part of the hot rolling production line at the joint stock company and Shougang Jingtang Company. This was a breakthrough within the group which increased the service life of the equipment several times over and represented a successful application of technology from laboratory R&D in an industrial setting.

As one of the most eye-catching technologies in Industry 4.0, metal 3D printing technology can not only directly print and manufacture complex machinery parts, but also repair and modify parts, thus giving new life to old scrap parts. This is of great significance for innovation and the promotion of green sustainable development within the manufacturing industry.

In view of the potential demand for the remanufacturing of key equipment within the iron and steel industry, a research team at the Shougang Research Institute of Technology has systematically studied the key issues in metal 3D printing remanufacturing technology as it relates to remanufacturing processes, such as particle size distribution, particle shape, material performance, energy input, tissue transformation and stress distribution and pretreatment and post-treatment technology in remanufacturing processes.

After Shougang Jingtang Company raised the issue of repairing the F3 archway of the 2,250mm finishing mill, a project team composed of researchers from the Research Institute of Technology and the Machinery and Electric Co., Ltd began research and preparation work immediately.

Metal 3D printing remanufacturing technology has obvious advantages in archway restoration, but it is difficult to implement successfully. This is the first time that this technology has been combined with key equipment on a working production line. Because of the pressing demands of production on site, the repair window is only 96 hours. A series of steps, such as on-site engineering surface processing, on-site laser remanufacturing, on-site finishing, on-site inspection and rechecking, should all be completed within this 96 hour period. In order to ensure success on the first attempt, the project team spent six months engaged in extremely comprehensive preparation work. This preparation included; material selection based on use performance evaluation, powder supplier selection based on micro analysis, remanufacturing process window definition based on the arch material, repeated proportional model repair drills away from the production line and anticipation of potential problems, in order to develop solutions. Such thorough preparation work facilitated the successful repair of the F3 archway window surface of the finishing mill on the production line, with completion acceptance achieved 16 hours ahead of schedule. The repair results have been praised by field personnel.

The project team summed up the experience as one in which team members cooperated with each other, continuously improved repair efficiency and reduced the cost of the repair. Later, they went on to successfully repair arch window surfaces of 2,160mm rolling mills at the joint stock company and 1,580mm rolling mills at Jingtang Company. The application of this technology has provided strong innovation support for cost reduction, efficiency improvement, quality improvement and upgrading within the group.