Corrosion protection system

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. In addition, it clarifies decision-relevant aspects for specification, execution, and upkeep of protective measures under real operating conditions.

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. Distinguishing between preventive protection (robust design, coatings, sealing) and condition-based care (cleaning, re-preservation, touch-up) enables cost-efficient operation with high technical availability.

• Objectives of a corrosion protection system: maintain fitness for use, stabilize tolerances, protect seal interfaces and hydraulic components, and support predictable maintenance cycles and documentation.

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. Deposits and embedded abrasive fines can hold electrolytes and create oxygen concentration cells that further intensify local attack.

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. Under-deposit areas and crevices exhibit reduced oxygen exchange, forming differential aeration cells that drive localized pitting and crevice attack.

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.
• Underfilm corrosion: coating creep from edges, cuts, or impact damage with subsequent blistering and loss of adhesion.

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.
• Contamination during logistics: carry-over of de-icing salt on transport routes and splash zones during loading.
• Standstill conditions: stagnant moisture under covers and on horizontal surfaces accelerates crevice and under-deposit corrosion.

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. Clear separation of functional zones and protective zones in the specification and during repair improves durability and the quality of touch-up.

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.
• Use pH-neutral cleaners and soft tools for cleaning; avoid agents that leave hygroscopic residues.
• Define torque and lubrication points for pins and guides; wipe excess lubricant to prevent abrasive paste formation.

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.
• During standstill, store cylinders with rods retracted where possible to reduce exposure of polished surfaces.
• Use hose protection sleeves and correct clamping to prevent fretting and coating damage at contact points.

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, edge-zone strength, and proper curing at the specified substrate and ambient conditions. Stripe coats on edges, welds, and difficult geometries significantly reduce early underfilm attack.

Pretreatment and derusting

1. Cleaning: remove oil, grease, and dust, especially after work with tank cutters, steel shears, and Multi Cutters.
2. Mechanical derusting: brushing, needle scaler, or blasting depending on accessibility; break edges and remove burrs.
3. Intermediate cleaning and prompt coating to avoid the formation of flash rust.
4. Ensure substrate temperature remains above the dew point with adequate ventilation; avoid trapped moisture before coating.
5. Verify surface cleanliness and profile; document preparation steps for traceability.

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.
• Stripe coats at edges, weld seams, and fastener heads to increase local film build and delay creep.
• Observe recoat intervals and curing times; insufficient curing reduces chemical resistance and adhesion.
• Use contrasting colors between coats where helpful to assess coverage during maintenance.

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. Where coatings cannot be maintained, use defined preservation films and cleaning routines instead of paint.

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. Design measures such as sloped top surfaces, drainage paths, and protected fastener seats reduce standing moisture and facilitate cleaning.

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.
• Use moisture control measures where feasible, such as desiccant breathers or controlled storage environments.
• After service involving open circuits, purge residual air and check for emulsified oil that may indicate water 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.
• Maintain drainage openings and low points; remove standing water and deposits in recesses.
• Perform timely touch-up with compatible repair materials on chipped areas, including at cable clamps and hose supports.

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. Inspect fasteners, lifting points, and jaw interfaces for fresh impacts and restore preservation on exposed base metal.

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. Pay attention to crevices under guards and at motor mounts; vacuum and re-preserve these zones after each shift in dusty environments.

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. Ventilated covers that do not trap moisture reduce the risk of crevice corrosion on horizontal surfaces and under handles.

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. Where quartz-rich dust is present, avoid dry rubbing on polished rods; use damp microfiber and reapply a thin preservative film.

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. After contact with seawater or de-icing brines, rinse with fresh water, dry thoroughly, and re-preserve without delay.

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. Defined acceptance criteria and photo documentation improve traceability across operating locations and shifts.

• 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.
• After repairs, check for pinholes on accessible surfaces and confirm adhesion at feathered edges of touch-up zones.

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. Stable blocking and correct lashing avoid coating damage by chafing and point loads.

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.
• Where compatible, use volatile corrosion inhibitor packaging for small components and spare parts; replace according to the product guidance.
• Prefer breathable, UV-stable covers over airtight tarpaulins; allow airflow to prevent moisture accumulation.

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. Repair-first strategies and condition-based touch-up reduce material consumption and support resource efficiency without compromising technical reliability.

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. Ensure adequate ventilation, prevent ignition sources for solventborne products, and use appropriate personal protective equipment. Observe safety data sheets and local disposal requirements. The statements here are general in nature and do not replace specific case-by-case assessment or binding requirements.