Selection of Grinding Wheels for Shear Blades 1. Brown Fused Alumina (A) Characteristics: High toughness and high hardness. Applications: Suitable for general grinding and deburring of carbon steel, alloy steel, ordinary steel, and malleable cast iron workpieces. 2. White Fused Alumina (WA) Characteristics: Higher hardness than Brown Fused Alumina with sharp cutting edges, though it has lower toughness. Applications: Ideal for grinding quenched steel, alloy steel, high-speed steel (HSS), and high-carbon steel. Commonly used for gear grinding and thread grinding. 3. Pink Fused Alumina / Chrome Corundum (PA) Characteristics: High toughness, excellent surface finish, and superior edge retention (form holding). Applications: Suitable for internal grinding and profile grinding of tool steel, alloy steel, and quenched steel. Used for tool grinding, copy grinding, and precision grinding of instrument parts where a high-quality finish is required; specifically designed for heat-treated tools. 4. Green Silicon Carbide (GC) Characteristics: Low toughness (brittle), high thermal conductivity, and extremely sharp cutting grains. Applications: Specifically suited for grinding cemented carbide (hard alloy).

Why high-alloy material shearing machine blades need to be tempered multiple times: High-alloy blades that are quenched at high temperatures need to be tempered multiple times.  For example, medium-thick plate shears made of H13 (4Cr5MoSiV1) steel require more than two tempers. This is because these high-temperature quenched high-alloy steel blades contain more retained austenite after quenching. The purpose of multiple tempering is to allow the retained austenite to transform into martensite during tempering cooling, and the martensite formed from retained austenite then transforms into tempered martensite.  If a single long tempering is used, it is difficult to achieve the above structural transformations, resulting in insufficient tempering. This will lead to inconspicuous secondary hardening, poor dimensional stability of the workpiece, higher brittleness, and lower service life.  Licheng Knife is committed to popularizing industry knowledge for the wide audience of frontline sales professionals!

Reasons for the Poor Durability of H13 Shear Blades： In common heat treatment standards, technical requirements often specify only the hardness range. To reduce costs, outsourced heat treatment providers frequently focus solely on meeting this hardness requirement. During the heat treatment process, if the heating temperature or soaking time is insufficient, the alloying elements in the tool steel cannot fully dissolve into the austenite. This results in an inadequate quenched and tempered microstructure, leading to defects such as edge deformation (collapsing) and loss of shape during service. Solutions: 1.Conditioning Treatment: Subject the blade blanks to a preliminary quenching and tempering (conditioning) process to obtain an ideal pearlitic structure. 2.Graded Preheating: Implement multi-stage preheating and optimized soaking times to ensure the alloying elements are fully austenitized.

Shearing blades may suddenly develop cracks or break and fail during use. According to the type of damage, they can be divided into local damage (such as spalling, chipping, missing teeth, etc.) and overall damage, such as fragmentation, fracture, bulging, or splitting. A common characteristic is that most damage occurs at the parts of the blade that experience the greatest force, or in areas where stress is concentrated due to changes in the cross-section.  Based on the characteristics of the fracture process, it can be categorized into brittle fracture and fatigue fracture. Brittle fracture is mainly caused by metallurgical defects or process defects in the blade material, or overload due to improper operation; fatigue fracture is mainly caused by long-term use under cyclic stress and is commonly seen in the shearing of various medium and thick plates, as well as high-strength plates. Understanding the product and understanding the market are the keys to gaining the advantage!

Characteristics of H13 Material Shear Machine Blades： During the forging and heat treatment of H13 material, the surface is easily decarburized due to the influence of high-temperature heating. The drawback of surface decarburization is insufficient hardness. The deeper the decarburized layer, the greater the impact. The preventive measures are: firstly, to properly control the forging and heat treatment temperature; secondly, to apply paint or coating on the surface that requires hardness during heat treatment, in order to minimize decarburization as much as possible.

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Issue: Uneven Quenching Hardness in Large-Scale H13 Shredder Blades Insufficient Machining Allowance: The forging allowance is too small, resulting in inadequate removal of the "black skin" (surface decarburization layer). Consequently, the carbon content in certain areas of the blade remains too low. High Loading Density: Excessive furnace loads lead to overly dense packing during quenching. This prevents uniform coolant circulation, resulting in inconsistent cooling rates across the blades. Overheating or Prolonged Isothermal Holding: Underheating or excessive holding times can lead to coarse grain structures. Conclusion: Under actual production conditions, the first two points are the primary causes of failure. Licheng Blades: Committed to Excellence in Professional Heat Treatment Processes.

Using DC53 (Cr8W2vSi) steel for shear blade ensures exceptional performance. When quenched at 1040°C and tempered at 520–530°C, it consistently maintains a hardness of HRC 62–63. This effectively overcomes the common issues found in Cr12MoV, such as insufficient hardness after high-temperature tempering and poor toughness. Key Advantages: Superior Machinability: Offers excellent cutting and grinding properties. Structural Integrity: Eliminates the risk of cracking during Wire EDM (Electrical Discharge Machining) processing. Dimensional Stability: After tempering, retained austenite is almost completely transformed, rendering cryogenic treatment virtually unnecessary. Optimized Microstructure: When tempered at a low temperature of 200°C, carbides are distributed uniformly without the presence of massive carbides, resulting in outstanding toughness. Choose Licheng for your blade needs! With our professional technical support, Licheng Knife provides you with the perfect solution for every application.