Wear parts are components that wear down through regular use and are therefore replaced at fixed or condition-based intervals. In hydraulic demolition and splitting technology—such as on concrete demolition shears, stone and concrete splitters, combination shears, multi cutters, steel shears, tank cutters, stone splitting cylinders as well as the associated hydraulic power packs—they largely determine performance, precision, and occupational safety. Anyone who understands the function, loads, and care of wear parts can extend service life, avoid unplanned downtime, and safeguard the quality of concrete demolition, building gutting, rock excavation, tunnel construction, natural stone extraction, and special operations.
Definition: What is a wear part
A wear part is a component for which material loss or fatigue is unavoidable under proper use. Typical mechanisms include abrasion (frictional wear), adhesion (material transfer), surface fatigue, impact loading, corrosion and—in hydraulic systems—also cavitation and fluid aging. For tools such as concrete demolition shears or stone and concrete splitters, this affects, among other things, cutting edges, jaws, pressing bars, pins and bearing bushings, seals, hose lines, quick couplings, and filters. Hydraulic power packs also contain wear parts, such as pump components, valve seats, filter elements, and sealing systems. What matters is that wear remains predictable: maintenance, inspection, and the targeted replacement are integral to safe and economical operation.
Typical wear parts on demolition and splitting equipment
The extent of wear depends on tool geometry, material pairings, surface hardness, lubrication, hydraulic pressure, impact rates, and on the material being processed (e.g., concrete with reinforcing steel, natural stone with high quartz content, steels). At a glance:
- Concrete demolition shears: Cutting and breaking jaws, blade strips, press and wear plates, pins and bushings at pivot points, slew ring bearing components (if present), seals and hose bundles.
- Stone and concrete splitters: Wedges and counter-wedges, spacer plates, pressure and tension rods, guides, sealing systems of the stone splitting cylinders, high-pressure hoses and couplings.
- Combination shears / multi cutters / steel shears / tank cutters: Cutting blades, anvils, blade holders, wear protection strips, bearing points, seals, hydraulic rotary feedthroughs.
- Hydraulic power packs: Filter elements, seals, couplings, hoses, pump elements, valve seats; also oil as the working medium with limited aging stability.
Wear mechanisms and influencing factors
Wear arises from the interaction of load, material, and environmental conditions. The following mechanisms are particularly relevant in practice:
- Abrasion: Hard minerals (e.g., quartz in concrete and natural stone) cause scoring and material removal on cutting edges and jaws.
- Impact and shock loading: Alternating peak loads promote micro- and macro-cracks, especially at edges and bores.
- Adhesion and cold welding: With metal-to-metal contact without sufficient lubrication (pins/bushings), galling and material transfer occur.
- Corrosion: Moist, chloride-laden environments and long downtimes promote pitting or crevice corrosion, including under residual stresses.
- Cavitation and oil aging: In hydraulic systems, gas bubbles and aged media damage seals, valves, and pump surfaces.
Influence of application areas
The application areas shape the wear pattern significantly:
- Concrete demolition and special deconstruction: Concrete demolition shears often work on reinforced concrete; switching between hard aggregate and steel promotes edge rounding and blade breakage, joints are subjected to shock loads.
- Building gutting and cutting: Combination shears and multi cutters encounter varying cross-sections; nonuniform material thicknesses create bending and torsional peaks at the blades.
- Rock excavation and tunnel construction: Stone and concrete splitters as well as stone splitting cylinders are exposed to highly abrasive mineral phases; wedges and counter-wedges benefit from high surface hardness and a correctly aligned force line (see Rock demolition for typical boundary conditions).
- Natural stone extraction: Repeated splitting within the same grain matrix requires consistent wedge geometries; seals of the cylinders are exposed to dust and particles.
- Special operations: Temperature deviations, moisture, or contaminated media impose additional requirements on seals, hoses, and corrosion protection.
Condition assessment: inspection and measurement practice
A systematic condition assessment is the basis for plannable maintenance. The aim is to detect critical wear dimensions at an early stage and to decide safely whether reconditioning or replacement is required.
Visual and functional inspection
- Inspect cutting and breaking edges for chipping, cracks, edge rounding, and uneven wear.
- Check pins/bushings for play, run-in marks, surface cracks, discoloration (overheating), and galling marks.
- Assess seals for sweating, leakage, swelling, or embrittlement; check hydraulic lines for chafe marks and bend radii.
- Hydraulic power packs: filter condition, differential pressure indicator (if present), pump noise, temperature behavior, oil condition (color, odor, particles).
Measuring tools and key parameters
- Calipers/gauges to determine remaining cutting edge length, edge radius, and pin diameters.
- Check axial and radial play at pivot points; record slew ring bearing play (if present).
- Document hydraulic pressure and flow rate under load; evaluate the system’s pressure-holding behavior.
Maintenance, lubrication and oil management
Consistent care measurably reduces wear. Especially on concrete demolition shears and stone and concrete splitters, clean, regular lubrication of the joints greatly extends the service life of pins and bushings.
- Lubrication: Service lubrication points according to the manufacturer’s specifications; remove dusty deposits beforehand to avoid three-body abrasion.
- Fasteners: Check tightening torques; loosened screw joints increase relative movement and thus wear.
- Oil condition: Adhere to change intervals and filter replacement; particles and water accelerate seal wear and component erosion.
- Quick couplings: Keep clean and clean before coupling; dirt ingress acts like an abrasive in the system.
Replacement criteria and maintenance strategies
Depending on the operating profile, preventive, condition-based, or mixed strategies make sense. The goal is safe and economical operation without consequential damage to neighboring components.
- Blades/jaws: Replace in case of cracking, unacceptable edge rounding, or when geometry no longer guides the cut/fracture line cleanly; for bolted-on blade strips, replace in time to protect carrier parts.
- Pins/bushings: Replace when permissible play limits are exceeded, upon crack indications or galling marks; always replace in pairs and with a compatible material pairing.
- Seals/hoses: In case of leakage, signs of aging, or after damage, replace immediately; renew hose lines at regular intervals.
- Filters/oil: Replace after operating hours or based on condition (differential pressure, oil condition); keep oil level and cleanliness continually in view.
Refurbishment and repair
Hardfacing (build-up welding), grinding, or resetting blade strips are established measures. Note that heat input can change microstructural properties. Repair procedures should be aligned with the technical specifications and approvals of Darda GmbH.
Materials, hardness and surfaces
Wear parts are often made from tempered tool steels, wear-resistant fine-grain steels, or case-/induction-hardened components. The right combination of core toughness and surface hardness is critical: an overly hard, brittle surface can chip; a soft surface wears too quickly. Surface treatments and coatings can reduce abrasion and adhesion but require correct processing and compatible mating partners.
Relation to products and applications
The selection and care of wear parts should always be matched to the specific tool and application area:
- Concrete demolition shears in concrete demolition and during building gutting benefit from durable cutting edges and precisely fitting bearing points; robust joints and even force distribution are important to separate reinforcing steel and aggregates in a controlled manner.
- Stone and concrete splitters in rock excavation, tunnel construction, and natural stone extraction require precise wedge geometries and tight cylinder systems; wedges and counter-wedges are highly loaded and should be inspected early.
- Combination shears, multi cutters, steel shears, tank cutters require blade sets tailored to the material and regular checks of blade holders and guide rails to keep kerf and cut quality stable.
- Hydraulic power packs provide the required pressure and flow rate; clean filters and tight couplings protect downstream wear parts in all tools.
Occupational safety and legal notes
Worn components increase the risk of component failure. Principles for safe operation:
- Remove tools with cracks, excessive play, or leaks from service and inspect.
- Depressurize before working on hydraulic lines, seals, or screw joints.
- Use only approved wear and spare parts; perform assembly according to the manufacturer’s instructions of Darda GmbH.
- Ensure personal protective equipment and a safe working environment; secure loads against unintended movement.
Legal requirements may vary by country and application environment. Inspection and maintenance intervals, documentation obligations, and personnel qualifications should comply with generally accepted engineering practice and applicable regulations.
Sustainability, disposal and documentation
Wear parts are often made of high-quality materials and can be recycled in many cases. Proper separation of metals, elastomers, and residual materials facilitates return to material cycles. Durability results from clean processes: dust management at the construction site, oil care, corrosion-protective storage, and complete documentation of inspections, measurements, and replacement dates. In this way, the operability of concrete demolition shears, stone and concrete splitters, and the associated hydraulic power packs is sustainably ensured.