Why jaw plate of jaw crusher wears easily analysis

Why jaw plate of jaw crusher wears easily analysis

Introduction

Jaw plate (tooth plate) is the main wear-resistant part of jaw crusher. It directly squeezes and impacts stone materials during crushing. Fast wear is one of the most common failures, which increases spare parts cost, reduces product granularity and lowers production efficiency. This article analyzes the root causes of rapid jaw plate wear from material characteristics, equipment structure, operating parameters and human operation.

2. Material Property of Raw Ore

  1. High hardness & abrasive rock Ores like granite, basalt, quartzite have high Mohs hardness and strong abrasiveness. Each extrusion will continuously scrape the jaw plate surface, accelerating tooth wear. Soft limestone causes relatively mild wear.
  2. High mud & moisture content Wet mud adheres to jaw plate surface, forming abrasive paste. The mixture of fine stone powder and mud acts like grinding paste, scouring the tooth profile continuously.
  3. Foreign hard impurities mixed in feed Iron blocks, steel bars and other metal scraps entering crushing chamber will produce strong impact, cause local denting, crack or abnormal pitting on jaw plate.

3. Jaw Plate Material & Manufacturing Quality

  1. Unqualified wear-resistant material High manganese steel (Mn13, Mn18) is standard for jaw plates. If raw material composition is not up to standard, insufficient manganese content or improper heat treatment, the jaw plate cannot form work-hardening layer under impact. Its surface remains soft and wears quickly.
  2. Casting defects Internal shrinkage porosity, sand holes, cracks and uneven hardness during casting will lead to partial rapid wear or early fracture.
  3. Incorrect tooth profile design Tooth shape, tooth height and tooth pitch do not match the crushed material. Sharp tooth tips wear down rapidly, and poor bite effect increases sliding friction between stone and jaw plate.

4. Equipment & Assembly Factors

  1. Unstable jaw plate installation Loose fixing bolts, failed backing plate cause jaw plate to shake and vibrate during operation. Relative sliding between jaw plate and crusher body intensifies abrasion; local stress concentration may break the jaw plate.
  2. Uneven feeding, one-side feeding Materials only pile on one side of crushing chamber. Single-side jaw plate bears continuous load, leading to asymmetric wear.
  3. Too small discharge opening Small CSS (closed side setting) increases material retention time inside the chamber. Stones repeatedly squeeze and rub against jaw plates, greatly boosting wear speed.
  4. Eccentric shaft and bearing abnormal clearance Worn bearings cause movable jaw swing trajectory deviation. The jaw plate produces abnormal sliding friction instead of pure squeezing action, accelerating surface wear.

5. Improper Operation & Production Parameters

  1. Overloading feeding Continuous overfeed leads to material choking in crushing cavity. Stones are not only squeezed but also slide heavily along jaw plate surface.
  2. Oversized feed size Raw stone size exceeds the maximum allowed feed opening. Large blocks pound jaw plate teeth violently, causing impact wear and chipping.
  3. Unreasonable matching of crushing force Long time running under overload condition destroys the work-hardening layer of high manganese steel jaw plate.
  4. No regular position exchange Most jaw plates can be flipped top-to-bottom for reuse. If operators skip turning work, one section wears out completely while the other side remains unused, wasting wear resistance life.

6. Wear Mechanism Summary

Two main wear modes on jaw plate:

  • Impact wear: Stone strikes the jaw plate, produce plastic deformation and tiny surface peeling.
  • Abrasive wear: Hard mineral particles slide on the plate surface and scrape off material. High manganese steel relies on impact to form hard work-hardening layer. If impact is insufficient or sliding friction is excessive, wear will be significantly faster.

7. Corresponding Improvement Measures

  1. Control feed quality: Remove metal impurities, reduce mud content, strictly limit maximum feed size.
  2. Select qualified high manganese steel jaw plate with standard casting and heat treatment.
  3. Check jaw plate fixing bolts regularly; ensure firm installation.
  4. Optimize discharge gap, avoid too small CSS; prevent material choking.
  5. Avoid unilateral feeding; use uniform feeding equipment.
  6. Flip jaw plate periodically to balance wear and extend service life.
  7. Maintain crusher main bearing and eccentric assembly to keep normal movable jaw movement track.

8. Conclusion

Easy wear of jaw plate is the combined result of ore property, jaw plate quality, assembly state and operation method. Targeted control of feeding, regular inspection and timely flipping jaw plates can effectively extend service life and reduce downtime cost.