A corrosion protection system is a key component of occupational safety and operational safety in the practice of concrete demolition, special demolition, as well as in rock excavation, tunnel construction, and natural stone extraction. Steel-intensive tools such as concrete demolition shears, hydraulic rock and concrete splitters, combination shears, Multi Cutters, steel shears, tank cutters, rock splitting cylinders, and the associated hydraulic power packs operate in moist, abrasive, and chemically stressed environments. A well-designed corrosion protection system preserves function, dimensional accuracy, and service life and reduces unplanned downtime. The following content is conceived as a mix of glossary and practical guide and establishes the technical relevance of corrosion protection measures in the named application areas—without advertising statements, but with a practical focus on the tools and assemblies of Darda GmbH.
Definition: What is meant by a corrosion protection system
A corrosion protection system (corrosion protection for ferrous materials) comprises all preventive and reactive measures that slow down or prevent the electrochemical oxidation of steel. These include design measures, choice of materials and surfaces, coating systems, lubricants and preservatives, cleaning and drying processes, storage conditions, inspection, and maintenance. In deconstruction, building gutting and cutting operations, as well as in rock excavation and tunnel construction, these measures must withstand real-world loads from moisture, chlorides, concrete slurries, abrasion, mechanical impact loads, and temperature changes. The goal is long-term operational safety with reasonable effort over the entire service life.
Causes and mechanisms of corrosion in deconstruction and rock excavation
Corrosion is an electrochemical process that occurs on steel surfaces when moisture and oxygen (often with salts and fine dust) form a conductive film. In demolition and extraction environments, concrete alkalies, chlorides from de-icing salts, splashing water, slurries, and prolonged moisture phases accelerate the reaction. Mechanical actions locally remove protective layers and open new attack points.
Electrochemical fundamentals
Rust forms from local anode and cathode areas on the steel surface. Different potentials arise from stresses in the material, microstructural differences, temperature gradients, deposits, or contact with nobler metals. The more conductive the electrolyte film (e.g., salt-laden spray water), the faster corrosion progresses.
Typical damage mechanisms
- Uniform (general) corrosion: even material loss; gradual reduction of wall thicknesses and tolerances.
- Crevice corrosion: in joints, under seals, and in bolted connections; difficult to detect, critical for joints of concrete demolition shears and combination shears.
- Pitting corrosion: localized, often beneath deposits; hazardous on piston rods and seal lips.
- Galvanic corrosion: when dissimilar metals contact, e.g., steel to brass or stainless steel at hydraulic fittings.
Environmental and operational factors
- Moisture cycles: condensate on cool nights, warmed surfaces during the day; microclimate in tunnels favors prolonged moisture phases.
- Chemical influences: cement paste (alkaline), chlorides, sulfates; deposits increase the conductivity of the moisture film.
- Mechanical abrasion: chipping and scratches remove protective layers at cutting edges, jaws, and edges.
- Temperature changes: stresses in the paint film, microcracks, and underfilm moisture ingress.
Corrosion protection system for concrete demolition shears and rock and concrete splitters
Concrete demolition shears and rock and concrete splitters from Darda GmbH operate on exposed surfaces under high compressive and shear forces. Corrosion protection must account for mechanical removal and chemical influences in equal measure. Transitions between heavily loaded functional surfaces (cutting edges, jaws, guides) and surfaces requiring protection (housings, fastening points) are particularly critical.
Protection on functional and contact surfaces
- Regular removal of concrete residues and slurries, especially at joints, centering features, and bolted connections.
- Thin-film, non-sticky preservation on bare surfaces outside the active cutting zone; avoid heavy build-up on contact surfaces.
- Immediate touch-up of damage in the coating system on side parts, grip points, and protective shrouds.
Cylinders, seals and lines
- Piston rods: clean after use and preserve with a suitable water-displacing film; do not use abrasive cleaners.
- Hydraulic lines and fittings: use protective caps and dust caps during transport and storage; minimize galvanic corrosion with mixed materials.
- Rock splitting cylinders: protect surfaces from impact loads, repair paint chipping early.
Surface preparation and coating systems
An effective coating system is based on solid pretreatment, a suitable primer, and a durable topcoat. In practice, combinations of zinc-rich primer, robust intermediate coat (e.g., epoxy), and a mechanically resilient topcoat have proven effective. Critical factors are adhesion, sufficient film thickness, and edge-zone strength.
Pretreatment and derusting
- Cleaning: remove oil, grease, and dust, especially after work with tank cutters, steel shears, and Multi Cutters.
- Mechanical derusting: brushing, needle scaler, or blasting depending on accessibility; break edges and remove burrs.
- Intermediate cleaning and prompt coating to avoid the formation of flash rust.
Coating build-up
- Primer: active corrosion protection, good adhesion promotion.
- Intermediate coat: barrier effect, sufficient dry film thickness including at edges.
- Topcoat: abrasion resistance, UV resistance, and ease of cleaning.
Note: In areas with frequent slinging and tool contact (e.g., mounting interfaces, lifting points) choose robust, easily repairable systems and carefully blend repair areas.
Hydraulic power packs and components: corrosion protection system in detail
Hydraulic power packs from Darda GmbH combine steel housings, piping, valve blocks, and fasteners. Corrosion can occur both externally and internally. Water in hydraulic fluids promotes internal corrosion on unprotected surfaces, while externally condensate and splash water cause attack.
Condensate, media and internal corrosion
- Monitor the moisture content of the hydraulic fluid; water promotes oxidation of internal steel surfaces.
- Regular oil changes as specified; filtration keeps abrasive particles away that mechanically disrupt protective films.
- Keep breathers and closure plugs clean to minimize moisture ingress.
External corrosion on power packs and fittings
- Keep surfaces free of dirt films that retain moisture.
- Reduce galvanic corrosion with dissimilar metals (e.g., steel/stainless/quenched and tempered steels) using isolating or sealing elements.
- Retighten bolt heads and flanges and apply localized preservative without impairing sealing faces.
Maintenance, cleaning, and storage by application area
Concrete demolition and special demolition
Rinse off cement paste and alkaline slurries immediately; residues can undercut coatings. Dry concrete demolition shears and steel shears after use, lightly oil moving parts, and promptly touch up damage in the coating system.
Building gutting and cutting
Indoor work generates fine dust that binds moisture. Regularly wipe surfaces and keep ventilation and drainage openings clear to prevent corrosion nests. Thoroughly clean tank cutters after contact-intensive work.
Rock excavation and tunnel construction
Prolonged moisture phases and condensate require consistent temporary preservation during downtimes. Do not store rock and concrete splitters or rock splitting cylinders directly on wet ground; dry bearing surfaces and use supports.
Natural stone extraction
Fine mineral dusts are abrasive. After shifts with high dust exposure, blow off, wipe down tools and power packs, and check preservative films. Protect joints and pin bearings with a suitable lubricant against moisture.
Special operations
When working with chloride-bearing media (e.g., in coastal areas) plan tighter inspection intervals and more frequent cleaning. Apply temporary protective films to exposed steel surfaces and document renewal intervals.
Inspection, documentation, and test methods
Systematic inspections detect corrosion at an early stage. Clear checkpoints are useful for heavily loaded tools such as combination shears, Multi Cutters, and concrete demolition shears.
- Visual inspection: edges, joints, pin bearings, piston rods, hose connections, mounting interfaces.
- Coating thickness checks on critical areas; account for edge-thickness reductions.
- Functional test: smooth movement, leak-tightness, noise behavior.
- Documentation: damaged areas, measures, date, operating environment.
Temporary preservation, transport, and storage
Between deployments or during seasonal downtimes, suitable preservation prevents new rust formation. For transport, covers and caps protect exposed surfaces from stone impact, splash water, and salt.
Recommendations for idle periods
- Store clean, dry, and ventilated; avoid condensate formation.
- Renew protective films on uncoated surfaces; keep functional surfaces clear.
- Avoid contact with concrete and damp ground; use dunnage.
Sustainability and cost-effectiveness
A robust corrosion protection system lowers life-cycle costs through fewer failures, reduced parts wear, and more predictable maintenance. Durable, repair-friendly coating systems, easily accessible inspection points, and standardized care procedures facilitate operation of tools and hydraulic power packs from Darda GmbH in all application areas.
Occupational safety and environmental aspects when using corrosion protection products
When handling cleaners, solvents, and coatings, generally accepted safety rules apply. Use materials sparingly, for their intended purpose, and in accordance with manufacturer information. Treat and dispose of wastewater and grinding dust properly. The statements here are general in nature and do not replace specific case-by-case assessment or binding requirements.