Flying shear knives for rolling mills

Flying Shear Knives for Rolling Mills: Materials, Process and Advantages

1. Common Blade Materials

1.1 6CrW2Si

• Material type: Alloy Tool Steel

• Key features: Has tungsten; good red hardness and wear resistance

• Use for flying shear knives: Fits low-temperature, low-impact tasks (e.g., cold rolling trimming)

1.2 H13 (4Cr5MoSiV1)

• Material type: Hot Work Die Steel

• Key features: Good high-temperature strength and thermal fatigue resistance

• Use for flying shear knives: Core material for rolling mills; cuts hot rolled plate, high-strength alloy steel and stainless steel thick plate

2. Core Material Details

2.1 H13 (4Cr5MoSiV1) – Core Material

• Performance: After heat treatment, hardness is HRC50-55. It resists impact and high temperatures well, has good toughness and hardenability. These traits match rolling mill flying shear needs.

• Application: Widely used in all rolling mills. Cuts hot rolled plate, high-hardness round steel and ordinary alloy steel in hot and cold rolling lines. Adapts to high-speed cutting.

• Advantages: Good for heavy-impact work. Resists high-speed shear impact, prevents chipping or breaking. Adapts well to complex rolling mill conditions; easy to produce.

2.2 H13K – Modified H13 (High-End Material)

• Performance: Upgraded from H13. Keeps H13’s impact resistance, but has better toughness, high-temperature stability and fatigue resistance. Easier to harden than regular H13. Fits large rolling mills’ long-term heavy work.

• Application: For large rolling mills with high demands. Cuts extra-thick steel plates, heavy alloy steel and large structural steel in hot strip and wire rod mills. Meets high-efficiency continuous cutting needs.

• Advantages: More resistant to impact and fatigue than regular H13. Lasts 20%-30% longer in heavy rolling mill work. Best choice for high-efficiency, large rolling mill flying shear knives.

3. Strengthening Process (Key for Performance)

3.1 Basic Heat Treatment Steps

1. Use vacuum heat treatment instead of ordinary air quenching. This reduces surface oxidation and decarburization, ensuring uniform hardness. It helps keep cutting precision during high-speed work.

2. Temper at 180-220℃ right after quenching. This removes internal stress, prevents deformation or cracking, and stabilizes hardness and toughness. It ensures long service life during continuous work.

4. High-Performance Flying Shear Knives

4.1 Why Our Flying Shear Knives Are Better

• Good Red Hardness (H13 & Custom Alloys): Hot rolling temperatures can exceed 600°C. We use high-quality H13 and advanced powder metallurgy steels. They have excellent red hardness, so the blade won’t soften during high-speed, continuous hot cutting.

• Strong Impact Toughness: Flying shear cuts are fast and forceful. Our knives go through special vacuum heat treatment (50-56 HRC). This creates a structure that absorbs shock without small cracks, avoiding sudden blade failure on the line.

• Micron-Level Precision: To cut moving materials cleanly, blade parallelism and flatness are critical. Our CNC precision grinding ensures each knife fits perfectly with the rotary drum. This reduces vibration and extends shear bearing life.

4.2 Uses in Rolling Mills

• Hot Strip Mills: Cuts thick slabs and hot-rolled coils reliably

• Wire Rod & Bar Mills: High-speed cutting for rebar and wire

• Cold Rolling Lines: Precise trimming and cross-cutting with no burrs

4.3 Boost Your Mill’s Efficiency