Shear blades are among the most critical components in the metalworking and machinery manufacturing industries

As a leading manufacturer of steel blades and industrial knives with a length capacity of up to 6 meters, TFI specializes in manufacturing single-piece shear blades measuring 3100 x 75 mm, specifically engineered for shearing machines in industrial metalworking plants. While producing these blades in long lengths as a single piece offers unparalleled structural advantages, it also introduces highly complex technical challenges during the manufacturing process.

1. Advantages of Single-Piece Manufacturing

• Higher Cutting Precision: Single-piece blades feature no seams, joints, or steps. This ensures a perfectly uniform, burr-free cut across the entire 3.1-meter length.
• Even Stress Distribution: Upon impact with the metal sheet, the machine’s force is balanced uniformly throughout the blade, eliminating the risk of breakage at joint points—a common issue in multi-segment blades.
• Easier Calibration: Adjusting the blade clearance between the upper and lower knives is significantly faster and more precise when using a single-piece design.

2. Premium Material Selection

For a blade measuring 3100 mm in length and 75 mm in width, selecting a steel grade that strikes the perfect balance between hardness and toughness is vital. The most widely used alloy steels include:

• 1.2379 (D2) Steel: The ideal choice for cutting thin to medium sheets, offering exceptional wear resistance.
• 1.2767 or 1.2344 (H13) Steel: Best suited for thicker plates or variable thicknesses due to its superior toughness and high impact resistance.

3. Key Manufacturing Stages at TFI

Manufacturing a component with this substantial length and relatively narrow width requires strict adherence to rigorous engineering standards across three main phases:

A) High-Precision Pre-Machining

• The raw ingot must undergo a thorough forging process to guarantee a uniform metallurgical grain structure.
• Rough machining (milling) is executed with highly precise dimensional tolerances, leaving the optimal allowance for final grinding.

B) The Heat Treatment Challenge

The greatest technical obstacle in a 3100 mm long blade is preventing distortion (warping) during the hardening process.

• Vertical Vacuum Furnaces: To prevent bending, the blades are suspended vertically and hardened under strictly monitored temperature profiles.
• Optimal Hardness: The standard hardness for these blades is maintained between 54 to 60 HRC (Rockwell C), depending on the specific application and sheet metal type.
• Tempering: A minimum of two to three tempering cycles is mandatory to stabilize the crystalline structure of the steel and relieve residual stresses.

C) Precision Final Grinding

Following heat treatment, the blade is mounted on long-bed magnetic surface grinders.

• Parallelism Tolerance: Across the entire 3.1-meter span, any deviation in parallelism must not exceed a few hundredths of a millimeter.
• Edge Sharpness: The cutting edge angle (typically 80 to 85 degrees) is ground with absolute precision, utilizing specialized cooling to prevent any thermal burning on the cutting edge.

Conclusion

Investing in a single-piece 3100 x 75 mm guillotine shear blade guarantees an extended service life and superior cutting quality on the production line.
TFI’s capability to manufacture industrial knives up to 6 meters reflects a mastery of advanced heat treatment and precision machining—eliminating distortion risks and delivering the highest global standards to metalworking factories worldwide.