Technical Article
Pelletizer Knife Life and Material Selection
Pelletizer knife life depends mainly on the working-area material, the knife body, and how the knives run against the die face. This article summarizes the reference service life JINFENG sees for each material and how to match the knife to the line.
Published 2026-09-25 by JINFENG engineering, Shenyang Jinfeng Special Equipment Co., Ltd.
Service Life by Working-Area Material
| Working-area material | Wear resistance | Self-sharpening | Reference life | Typical use |
|---|---|---|---|---|
| TiC-NiCr cermet | Excellent | Good | 3 months or more | PE, PP |
| TiC-Fe steel-bonded carbide | Good | Excellent | 2 months or more | PP, PE |
| Tool steel (9Cr18Mo, 9Cr18MoV, W6, T15) | Lower | Excellent | 10 days or more | High melt-index grades |
Composite knives combine a wear-resistant working area with a tougher steel body. JINFENG first patented a cermet-insert composite pelletizer knife in China in 1995, and its service life reached the level of comparable imported knives.
Knife Body Materials
- 40Cr: good toughness; for lines with frequent process adjustments and slightly alkaline water.
- 2Cr13: good corrosion resistance; for stable operation and slightly acidic water.
- 17-4PH: good overall properties; the most widely used body material.
What Shortens Knife Life
- A worn or uneven die face, which loads parts of the knife edge unevenly
- Incorrect knife-to-die-plate setting
- A knife material that does not suit the grade or water chemistry
- Chipping from hard contact, for example after an overhaul with incorrect settings
Knife life and die face condition are linked: a flat, sound hard face helps the knives last, and well-maintained knives protect the hard face.
Frequently Asked Questions
How long should pelletizer knives last?
As reference values from JINFENG supply experience: TiC-NiCr cermet knives three months or more on PE and PP, TiC-Fe knives two months or more, and tool-steel knives ten days or more on high melt-index grades.
What is self-sharpening in a pelletizer knife?
The ability of the knife edge to stay sharp as it wears against the die face. TiC-Fe knives have excellent self-sharpening, TiC-NiCr cermet knives good self-sharpening with higher wear resistance.
Why does knife body material matter?
The body carries the working area and sits in the process water. 40Cr is tougher and suits frequent process changes and slightly alkaline water; 2Cr13 resists corrosion better and suits stable operation and slightly acidic water; 17-4PH is a balanced, widely used choice.
Choose the Right Knife for Your Line
Send your knife drawing or sample, polymer, and water data, and JINFENG will recommend a material.
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