Why Blade Material Matters

Shredder blades are the business end of any size-reduction operation. They determine throughput, output quality, maintenance frequency, and operating cost. While cutting angle, knife count, and rotor speed all matter, blade material is the foundational choice. The wrong steel for your waste stream means rapid wear, frequent changes, and degraded output. The right material extends service life and keeps the machine running at design capacity. This guide matches blade materials to common industrial waste types.

Materials of shredder cutter out there vary, so do the materials of industrial waste, too. You have to know about the common cutter materials for main sources of industrial waste If you happen to work in the recycling business. ( cement waste is not covered by this article cause, in general, it’s not processed by cutter blade, but anvil hammer)

1. Wood and Paper

Brittle wood — Branches, twigs, cardboard, and paper. SK5 carbon tool steel is the economical choice. It offers adequate wear resistance for soft, brittle material. Poor hardenability limits its use to lighter-duty applications, but the low cost makes it practical for high-volume, low-abrasion streams.

Tough wood — Stumps, plywood, and discarded furniture. High manganese steel replaces SK5 here. Work-hardened depth reaches 10–20 mm at HB 500–550. Under high torque, manganese steel resists deformation and fracture far better than SK5. It is also more affordable than alloy carbon steels, making it the standard for demanding wood shredding.

2.For shredding plastic

In the plastic industry collectors and recyclers started their business pretty late compared to areas of scrap wood and paper&cardboard. Trash plastic can be generally a huge blend with at least the same amount of possible additives and fillers. They contain not only lower grade plastic but also high-value ones. Thus we need to recognize which type of plastic is in the input mixture.

a.For cutting off plastics of ABS、PE、PP board, etc.

In general, we’d choose alloy carbon steel, such as 65Mn spring steel, T10, and D2 for these plastics. That’s because these carbon steels are with great harden-ability and temper resistance to high impact load. These blade materials are generally utilized on the cut-off blade at lower cutting velocity and large torture. Concern data indicates that when cut-off blades have to bear traction that is more than 270Mpa. In the meantime are required to maintain the hardness of HRC52-55. A cut-off blade made of low-alloy steel will work well under the circumstance, taking credit for its property.

b.For crumbling plastics fragments and granules.

Granulator consists of a fixed cutter and hob cutter. Granulator’s rolling of hob cutters and sifter’s screening at the outlet process together plastic mixture into granules. Hob cutter is the major working part of the whole granulator’s system. The requirements for hob cutter’s heat-treatment hardness is around HRC58-62. Besides, crumbling knives requires to be more resistant to abrasion, high temperature, and impact. Thus, We prefer quenched carbon steel 9CrSi, spring steel 65Mn, or even HSS W18Cr4V. They are fine choices to fabricate all main plastic granules of PVC, PS, ABS, AS, and HIPS.

3.For shredding tyre rubbers

In light of the growing prices for precious metals exist in radial tires as well as raw rubber granule, all types of rubber waste recycling, trash rubber we mostly referred to “black trash” is gradually becoming “black gold” now. Contractors and dealers can easily procure wore tires from automobiles at a very sound price and process them into premium recycled rubber. Recycled tire rubber is not only a cheap but a versatile and environment-friendly material that has a wide range of usage in many places, right from the artificial golf course, to flame-retardant&deadening painting materials.

a.example

Take WANROOETECH shredder PNSS as an example. It can firstly cut passenger car tires of up to Ø 800mm into strips of approx. 150 mm- 300mm, then completely smash these pieces int to fine granules. Tire shredder’s hob cutter differs from plastic shredder’s. It consists of many tungsten carbide tips screw fixed and the main cutter body that made of a carbon tool steel. That’s because radial tyres are mainstream of auto-tires, in belt part of which there are many kinds of metal or hardening fiber working as tire cord, such as aramid fiber, Polyamide fiber, or even copper. These hard materials make tire’s strength, hardness, and toughness stronger than general plastic, which means shredding of tyre is hard than shredding plastic, in some degree. And that’s why Zerma have designed two shredders of pre-shred and shred, and choose tungsten carbide(WC) as the material of cutter bit.

b. property of Tungsten Carbide

Tungsten carbide has superior resistance to abrasion and high temperature for processing hard steel like copper and high carbon steel. At normal temperature, its hardness is around 69-81HRC. It still can keep hardness of 60 HRC at 1000℃. Compared to materials with lower properties, tungsten carbide is relatively more expensive. Thus, now shredder producers generally weld, braze or screw fix carbide tips on hob cutter’s body, instead of making the whole cutter body in tungsten carbide. Speaking of reducing cost, nowadays people get their shredders with knives that have larger concave, producing high-quality output, and indexable after worn-out.