Concave Local Spalling & Chipping? Check Causes from Three Aspects

The concave serves as the primary fixed cone liner of a cone crusher. Local spalling and chipping on its inner wall is a frequent fault. Once this fault occurs, it disturbs the crushing chamber profile, affects discharge conditions and raises consumption of spare parts. This article sorts out contributing factors from three dimensions: material impact, casting metallurgy and equipment operating conditions, to help on-site staff locate faults quickly and implement preventive control.

From the perspective of material impact, foreign hard objects that are difficult to crush, such as iron blocks and large cobblestones, may enter the feed stream. They strike the working surface of the concave at high speed. Instant impact load exceeds the bearing capacity of the material, cracks initiate on the surface and propagate gradually until spalling appears. Poor control of feed particle size allows oversized lumps to repeatedly strike the same spot, leading to material fatigue damage. Besides, sharp-edged ore creates combined cutting and impacting force on local areas and accelerates surface peeling. When dry and wet materials mix, fine powder carrying hard debris scours partial liner surfaces and increases the risk of chipping.

Casting metallurgy covers factors related to the base material of the concave. If shrinkage cavities, porosity, slag inclusions or other internal defects form during casting, these areas become stress-concentrated weak points. Under cyclic compressive load, cracks expand outward starting from defects and trigger surface spalling. Improper heat treatment leads to incomplete austenite transformation. The material lacks sufficient toughness and cannot absorb impact energy, resulting in brittle spalling. Uneven grain structure and local segregation cause inconsistent mechanical properties across the liner, and weak zones are prone to chipping.

Equipment operating conditions and assembly status can induce faults indirectly. Offset feeding, where material enters only one side of the crushing chamber, subjects one side of the concave to continuous eccentric compression and concentrated stress, accelerating crack growth. Improper adjustment of the discharge opening creates an overly thick material bed inside the chamber and sustains high compressive stress. Inappropriate liner assembly clearance or loose fasteners introduce extra vibration that continuously strikes the liner. Worn eccentric bushings or abnormal rotating speed shift the distribution of crushing force, increasing local load and triggering spalling and chipping.

For daily maintenance, operators can deploy iron removal for feedstock, control feed lump size strictly, carry out regular equipment inspections and check liner assembly and wear of eccentric components. Hunan Xiangjian Machinery Technology Co., Ltd. provides suggestions on concave and other wear part selection as well as working condition adaptation. Feel free to contact us for fault diagnosis and spare part inquiries.