Shredder and Crusher Blades: Matching the Steel to the Feedstock

Read your feedstock before you read a catalogue

Tyre shredding is pure impact and abrasion: steel beads inside rubber hit the blade like gravel. Mixed plastic waste is abrasion with surprises — the surprise being whatever metal someone left in the stream. Clean wood or biomass is the gentlest, and lets you run harder, keener steel.

The blade that lives eight months on biomass dies in six weeks on tyre scrap. Same machine, same blade shape — different steel.

Three grades, three jobs

6CrW2Si (HRC 54–58) is the impact champion: it bends a little rather than breaking, which is exactly what you want when uninvited metal arrives. Cr12MoV (HRC 58–62) wins on abrasion — longer life on abrasive plastics — but it needs cleaner feed. Carbide-inlaid edges are the last word on wear, at the price of needing feed that truly contains no metal.

Most recycling yards we work with run 6CrW2Si on the shredder and save Cr12MoV for the downstream granulator, where the feed is cleaner and the wear is steady.

Half of blade life is clearance, not steel

Blade-to-counter-knife gap set too wide feeds whole lumps to the edge and hammers it; set too tight and metal contact becomes certain. Rotors out of balance or shaft bearings worn turn every pass into a micro impact test.

When a customer says "your blades chip," the first thing we ask for is photos of the gap and the counter-knives. More than once the fix was a 20-minute adjustment, not a new set of blades.

Rotate, regrind, then replace

Two-edge blades give you four working edges if you rotate them on schedule instead of waiting for one edge to die. Regrinding restores geometry; replacing restores nothing the regrind could not. The economical unit is cost per tonne shredded, not cost per blade.

Send us the first worn set before you buy replacements. We measure what the wear did to the angles, and the replacement set arrives matched to your actual duty — not to a catalogue assumption.