In metal processing and manufacturing, the service life and stability of shear blades are critical determinants of production efficiency and operating costs. Addressing the demanding requirements of shearing 6–8mm thick Q345 steel plates, Licheng Blade has developed high-performance shear blades using the novel cold-work die steel LD, following extensive research into end use and material innovation. End users demonstrate that these blades achieve a fourfold increase in service life compared to traditional cold-work die steels such as SKD11, hot-work die steels like H13, and W6Mo5Cr4V2 high-speed steel, thereby resolving longstanding challenges related to blade chipping, limited service life, and difficulties in regrinding. 1. Main Problems of Shear Blades Made of Traditional Materials Traditional shearing blades have been tested with various die steels and high-speed steels, but practical production continues to reveal issues that negatively affect efficiency, precision, and cost. Edge Design and Usage Limitations: I.Wedge Angle vs. Strength: When it comes to knife cutting, like a pair of scissors, a smaller angle cuts more sharply but reduces strength and shortens life, while an excessive angle increases resistance. Blade angles generally range from 80° to 90°, with 90° typically chosen to maximize the number of available cutting edges. II.Overlap Angle Range: The included angle between dual edges during transverse shearing is 0–10 degrees, while longitudinal slitter blades intersect orthogonally. III.Bite Depth and Clearance: Edge engagement requires a balance of tightness and depth. Clearance and depth affect the sheared cross-section and blade life and must be analyzed based on the shearing method, tool dimensions, and sheet thickness. IV.Shear Root Design: Improper shear root height compromises the knife cutting edge. Thicker sheets generally need larger knives, and design thickness should be at least three times the material thickness. If the knife's outer diameter or width is larger than expected, this proportion can be reduced accordingly. Manufacturing and Process Challenges: Material selection, forging, heat treatment, and grinding. These complex processes rely heavily on extensive production experience. Operational Issues: I.Blunting and Wear: Low fatigue strength leads to edge wear and localized chipping, requiring frequent replacement or removal of large fatigue layers, which severely reduces productivity. II.Brittle Fracture Failure: This is the most severe failure mode on the knife working. While fatigue failure indicates poor wear resistance, brittle fracture can cause catastrophic interruptions in steel sheeting production or safety incidents and is closely tied to material selection. 2.Breakthrough Solution: The Advantages of LD Die Steel When shearing thick plates such as 6–8mm Q345 low-alloy high-strength structural steel, slitting blades must withstand extreme impact loads and frictional shear forces. The previous material c...