Steel cutting refers to the separating processing of steel components—from reinforcing steel and sections to tanks, pipelines, and steel beams. In the context of concrete demolition, special demolition, and interior demolition, precise, safe, and efficient cutting of steel is crucial to dismantle components in a controlled manner, reassign loads, and expose concrete elements. In practice, cold hydraulic separation technology is often combined with thermal methods. Tools such as concrete demolition shears, steel shears, combination shears, multi cutters as well as tank cutters and the associated hydraulic power packs from Darda GmbH are combined as required so that sparks, heat input, emissions, and structural requirements are taken into account.
Definition: What is meant by steel cutting
Steel cutting refers to the controlled separation of steel using mechanical, hydraulic, thermal, or abrasive methods. The goal is a defined cut with reproducible cut quality, a predictable kerf, and controllable heat and force input. In deconstruction, steel cutting is used to separate reinforcement from reinforced concrete, segment beams, cut up tanks and pipelines, or remove fittings such as guardrails, anchors, and steel posts. The choice of method follows the boundary conditions: material grade, wall thickness, accessibility, fire protection, environmental requirements, structural analysis, as well as the cut position relative to concrete and rock.
Methods of steel cutting: cold, hot, and combined
Steel cutting can be divided into cold and thermal methods. Cold, hydraulically operated cutting devices generate high shear forces without sparks and minimize heat input. Thermal methods such as flame cutting (oxy-fuel cutting) or plasma cutting are fast and flexible but produce heat-affected zones and spraying particles. In deconstruction practice, methods are combined: concrete bodies are cracked open with stone and concrete splitters, reinforcement is exposed and then cut with concrete demolition shears, steel shears, or multi cutters; large-format steel components are segmented for transport, and tanks are cut cold with special tank cutters when fire protection and explosion protection require it.
Fields of application in deconstruction and construction practice
Steel cutting is anchored in many areas of application and supports the structured sequence of demolition and assembly work.
Concrete demolition and special demolition
When removing reinforced concrete structures, pressure-relieving cracks are first created with stone and concrete splitters. After breaking open the concrete cover, exposed reinforcement can be selectively cut with concrete demolition shears. Advantage: cold cutting without sparks, low secondary damage, and a clear load transfer.
Interior demolition and cutting
In buildings, sections, pipe bridges, guardrails, and cable trays are dismantled. Hydraulic steel shears and multi cutters cut beams and rolled steel quietly and with low emissions, which facilitates operation in sensitive environments. Combination shears combine crushing and cutting functions to release and segment components in a single work step.
Rock excavation and tunnel construction
In underground works, temporary steel arches, lattice girders, or anchors are dismantled. Cold steel cutting minimizes ignition sources, which is especially relevant in poorly ventilated areas. For anchor heads and reinforcement cages, hydraulic cutting offers a precise, low-vibration solution.
Natural stone extraction
In the quarry, steel cutting mainly concerns the dismantling of steel frames, conveying equipment, and barriers, for example for modifications or safe deconstruction. The combination of mechanical loosening followed by cutting optimizes cycle times.
Special application
When dismantling tanks and pipelines—especially with residual media—cold cutting is often used. In such cases, cold cutting with tank cutters enables low-spark, controlled separation, and suitable hydraulic power packs from Darda GmbH support the process. Thermal methods are only considered after verified protective measures.
Tools and equipment in the context of steel cutting practice
The choice of tool depends on steel grade, geometry, and the working environment. Hydraulic systems are widely used in demolition and deconstruction.
Concrete demolition shears
Concrete demolition shears remove concrete cover, crush components, and cut exposed reinforcement. Their cold cut reduces sparks, heat damage, and smoke—a plus indoors and in sensitive surroundings.
Stone and concrete splitters
Splitters generate defined crack lines and relieve components. This reduces steel stress in the cutting area, making subsequent steel cutting easier and safer.
Steel shears, multi cutters, and combination shears
These tools cut sections, sheets, and reinforcement with high cutting force. Multi cutters cover a wide range of materials, while combination shears unite cutting and crushing—useful for segmenting.
Tank cutters
Tank cutters are designed for the cold cutting of vessels and pipelines. They minimize ignition sources and support workflows with increased requirements for explosion protection.
Hydraulic power packs
Hydraulic power packs from Darda GmbH supply the tools with pressure and flow. Properly sizing the power packs prevents performance drops, reduces heat generation in the oil, and ensures reproducible cutting times.
Method selection: criteria and decision logic
For a methodical selection, a structured assessment of the boundary conditions is recommended:
- Material: steel grade, sensitivity to heat input, coatings, corrosion
- Geometry: wall thickness, section shape, accessibility, position within a composite component
- Environment: fire protection, ventilation, water/dust management, vibration tolerance
- Objectives: cut edge quality, segment size, reusability of parts
- Resources: available tools, hydraulic power, personnel qualification
Cut quality, tolerances, and rework
The quality of steel cutting is evident in straightness, burr formation, heat-affected zone, and surface roughness. Cold hydraulic cuts produce no heat-affected zone and reduce microstructural changes, while thermal methods are faster but may require rework (deburring, straightening). For reinforcing steel in reinforced concrete, functional safety takes priority: short cutting times, a repeatable cut, and minimal edge influence.
Influencing factors on the cut edge
- Cutting force and tool geometry
- Cutting clearance and support conditions
- Steel hardness, toughness, alloying
- Temperature development and cooling (for thermal or abrasive processes)
Work preparation and process
Careful planning reduces risks and increases productivity. A proven sequence:
- Object analysis: material mix, layer structure, connection to concrete/rock, structural analysis, and load paths
- Method selection: prioritize cold methods where sensitivity to sparks and heat exists
- Access and safety concept: shoring, anchorage, cordoning, ventilation
- Preparation: open the concrete cover (e.g., with concrete demolition shears), relieve stresses (splitters)
- Cutting: use suitable steel shears, multi cutters, or tank cutters
- Segmentation and haulage: load-appropriate piece sizes, secure edges
- Rework and inspection: remove burrs, check edges, clean the area
Occupational safety, health, and environment
Steel cutting requires clear protective measures. In general: identify hazards in advance, define measures, and deploy trained personnel.
- Fire protection: avoid sparks and hot particles; favor cold methods where possible
- Emissions: minimize dust, smoke, and noise; provide extraction or ventilation
- Energy and media: protect the hydraulic hose line, avoid drip leaks, safely relieve pressure
- Lifting and loads: secured load paths, redundant anchorage points, exclusion zones
- Hazardous substances: carefully assess coatings and residual media in tanks and lines
Legal requirements, standards, and regulations must be checked and applied on a project-specific basis; the notes are general and not to be understood as binding advice for individual cases.
Productive combinations in composite assemblies
In the composite of concrete and steel, a sequential approach has become established: stone and concrete splitters create cracks, concrete demolition shears open the cover layer and reduce cross-sections, and then steel shears or multi cutters cut the reinforcement and steel sections. This sequence reduces tool load, lowers vibrations, and improves cut quality.
Typical challenges and proven solutions
- Confined access: use compact hydraulic cutting tools, reduce segment sizes
- High-strength steel: adjust cutting capacity and tool geometry, increase number of cuts
- Coated surfaces: locally remove coatings or allow for higher cutting force
- Residual stresses in the component: use splitters for relief, set anchors, plan the cutting sequence
- Sensitive environment: combine cold cutting technology, spark shielding, and extraction
Cost-effectiveness and quality assurance
Cost-effective steel cutting is based on appropriate tool sizing, stable hydraulic power, and a clear cycle. Process data such as cutting time, tool temperature, and burr formation serve quality assurance. Regular maintenance of cutting edges and inspection of hydraulic power packs from Darda GmbH maintain performance in continuous operation.