OFweek Laser Network News: The use of laser surface treatment technology can enable low-grade materials to achieve high-performance surface modification, to achieve the best combination of low-cost part manufacturing and high-performance working surface, with considerable economic and social benefits. Laser hardening relies on the heat conduction of the material matrix for self-cooling and quenching, without the need of cooling medium and related supporting equipment, low cost, and no pollution to the environment. The surface hardness of the parts after laser surface hardening is 15% to 20% higher than that of conventional quenching. The depth of the hardened layer is usually 0.3 to 0.5 mm. If a more powerful laser is used, it can reach 1 mm. The heat-affected zone of laser hardening is small, the quenching stress and deformation are small, the subsequent processing margin is small, and even some workpieces can be used directly after laser treatment.

The energy of the laser beam can be continuously adjusted, and there is no inertia. With the CNC system, parts with complex shapes and parts that are difficult to handle by other conventional methods can be locally hardened, and different laser hardening can be performed on different parts of the parts. Because of the above characteristics of laser surface treatment, it is particularly suitable for the surface of some parts and their local positions that are difficult to achieve by conventional hardening treatments (such as carburizing and carbonitriding quenching, nitriding, and high-intermediate frequency induction heating quenching, etc.) Strengthening treatment, therefore has unique advantages in mold manufacturing: it can realize the replacement of high-grade mold steel with low-grade mold steel or cast iron; the substitution of imported mold steel with domestic mold steel; the enhanced repair of molds (remanufacturing engineering) to reduce mold manufacturing cost. The application of laser surface hardening technology in mold manufacturing can integrate design, material selection, mold making, inspection, repair and other technologies, greatly shorten the design and manufacturing cycle, reduce production costs, change mold manufacturing methods, and ultimately integrate and enhance the entire mold industry Level. These advantages are unmatched by existing traditional technologies in terms of technicality, economy and serviceability.

For example, the SC6350 microcar longitudinal beam front thick plate drawing die has always been made of Cr12MoV material and is composed of 12 inserts. Due to the large quenching deformation during the manufacture of inserts, secondary processing is required. The influence of "seam" makes the processing cost and long cycle of the mold, and the part is prone to "pulling" phenomenon, which has not been solved. The surface of the mold is laser-quenched, and the 12 inserts of the original Cr12MoV and other materials are changed to nodular cast iron QT600-2 for integral casting. The surface of the mold is laser-strengthened and its hardness reaches 58-62HRC. After quenching, the mold is not deformed. It only needs to be slightly polished on the surface before it can be put into use. Compared with the original manufacturing process, after the mold is processed by laser, the material is saved by 40% to 60%, the processing time and tool cost are reduced by 30%, and the service life is greatly improved. It is particularly worth noting that the technical problem of "drawing and burning" parts of thick sheet drawing dies does not have a good solution in the world. The use of laser surface strengthening process treatment effectively solved this technical problem and improved The surface quality and dimensional accuracy of the stamping parts meet the requirements of the thick plate drawing die, which makes the choice of materials for mold design more extensive.

Another example is that the gray cast iron HT300 was used to cover the stamping parts of the microcar, and the hardness is only 28 to 32 HRC. When the mold is used, only dozens of pieces or even pieces of work need to be repaired, which seriously affects the processing schedule and increases labor intensity. After quenching and strengthening the mold surface by laser, the hardness can reach 58 HRC or more, which greatly improves the service life of the mold. Experiments show that after 5,000 consecutive punchings, the stamping can be continued without "great".