High-Impact Multi-Shaft Blades for Scrap Metal, ELV & E-Waste

D2 is optimized for wear resistance at the expense of toughness—it reaches HRC 58–62 but becomes brittle under extreme shock loading. When a D2 blade strikes an engine block, the impact energy exceeds the material's fracture toughness in microseconds, causing catastrophic hook shattering. H13 and 42CrMo (AISI 4140) possess inherently superior toughness; at HRC 50–54, they absorb the same impact energy elastically rather than fracturing.

For ELV primary shredding (car bodies, engine subassemblies), specify 1-hook or 2-hook low-profile designs with maximum root thickness. A low claw count concentrates the available machine torque onto fewer, robust hook contacts, generating the massive biting force needed to penetrate thick steel. High claw counts spread torque too thinly, causing the blade to slide over the metal rather than biting into it.

In heavy metal shredding, peak rotor torque spikes to 3–5× steady-state load during a hard strike. Standard single-keyed bores concentrate all this torque on one point, progressively widening the keyway and ultimately shearing the key. Wire-EDM splined bores distribute this massive torque evenly across 10 to 20 contact faces around the full circumference, reducing peak stress and protecting your expensive rotor shaft.

Key indicators include: (1) Visible hairline fractures at the hook root; (2) Outer diameter (OD) wear exceeding 10–15mm below nominal, indicating a loss of shear clearance; (3) Bore elongation, meaning the blade rocks on the shaft even under full tightening torque; (4) A throughput reduction of >20% at a constant motor load, indicating the blades are pushing rather than shearing the scrap.