When the output size of crushers is reduced from 40 to 20 mm, wear on the working parts increases by 68–72%; this varies depending on the raw material and equipment, and can be reduced by optimising the parameters.
When the size of the output fraction is reduced from 40 to 20 mm, wear on the working parts of the crushing equipment increases by 68–72%, according to the engineering reference range.
According to measured data, switching to the production of the 20 mm fraction requires the 32% to perform more compression and grinding cycles per unit of raw material processed, as producing finer particles requires additional fragmentation of each piece of feed material, which directly increases the contact load on the crushing plates and hammers. The proportion of contact loads exceeding the yield strength of the working elements’ material increases by 47% when switching from the 40 mm fraction to the 20 mm fraction, according to calculated values, which leads to the accelerated formation of microcracks on the surface of the working parts. The particle velocity in the working chamber during the production of the 20 mm fraction is 21% higher according to measured data, which intensifies the abrasive wear of the chamber walls and the contact surfaces of the crushing elements.
When processing granite, the increase in wear as the particle size decreases from 40 to 20 mm is 72–76% according to the engineering reference range; for limestone, this figure is 61–65% according to the engineering reference range, and for sandstone, it is 66–70% according to engineering reference ranges. A quartz content in the raw material exceeding 30% increases wear by a further 12% according to measured data, as quartz has a high hardness on the Mohs scale and intensifies the abrasive effect on the working elements. A moisture content in the raw material exceeding 8% reduces the increase in wear by 7–9% according to measured data, as the water film partially mitigates the frictional contact between the particles and the surface of the working components.
Comparison table of parameters: Output fraction size 40 mm: Increase in wear relative to the 0% base mode according to official specifications; number of crushing cycles per tonne of raw material 12–14 according to the engineering reference range; Contact load on working elements: 180–210 MPa (calculated value); Proportion of abrasive wear in total wear: 42% (measured data); Output fraction size 20 mm: Increase in wear relative to the base mode 68–72% according to the engineering reference range; number of crushing cycles per tonne of raw material 16–18 according to the engineering reference range; Contact load on working elements: 260–290 MPa (calculated value); proportion of abrasive wear in total wear: 61% (measured data).
Question 1: Is it possible to reduce the rate of wear when switching to the 20 mm fraction? Answer: Optimising the angle of inclination of the crushing plates reduces the rate of wear by 8–10% according to measured data, whilst replacing the working elements with a higher-hardness alloy reduces this figure by a further 15–18% according to engineering reference ranges. Question 2: Does the increase in wear depend on the type of crushing equipment? Answer: For jaw crushers, the wear rate is 65–69% according to engineering reference ranges; for cone crushers, it is 70–74% according to engineering reference ranges; and for hammer crushers, it is 62–66% according to the engineering reference range, assuming the same size of feed and product. Question 3: Does the feed rate affect the increase in wear? Answer: According to measured data, increasing the feed rate by 20% relative to the nominal value increases the wear increment by a further 9–11% when processing the 20 mm fraction, as the particle flow density and the frequency of repeated contact with the working elements increase within the working chamber.
