ENERGY SAVING CUTTING OF HOT STEEL SLABS

Información del proyecto

Identificador del acuerdo de subvención: EE.-00163-84

Proyecto cerrado

Fecha de inicio 1 Noviembre 1984

Fecha de finalización 31 Diciembre 1987

Financiado con arreglo a

• Programme (EEC) of demonstration projects relating to the exploitation of alternative energy sources and to energy saving and the substitution of hydrocarbons, 1983-1985

Coste total

€ 13 671 811,00

Aportación de la UE

€ 1 640 617,00

Coordinado por

Klöckner Stahl GmbH
Germany

Objetivo

Slabs are cut on a demonstration plant by a new process which, if successful, can be promoted throughout Europe, leading to substantial energy savings.
On the basis of tests, cutting with blades was rejected in favour of combined (with oxygen) beam cutting. Various shaped blades were used in the tests with unsatisfactory results.
Calculations on maximum cutting speeds, with optimum cut joint width, on 220 mm thick slabs, show that speed is limited by the oxygen supply.
Tests with burners set behind each other produced speeds of 800-900 mm/m. but with marked erosion at the joint edges. Rapid-cutting nozzles were faster than standard, positioned 130 mm from the slab.
These give very narrow joints (+/- 7 mm). Internal mixing nozzles provide greater thermal effect. Multiple high output burners were used.
Tests were carried out using vertical, rear and forward sloping beams, cutting both from above and below the slab and showed that high speeds could not be achieved with vertical flames, and those sloping to the rear.
Basically a burner applied from below gave better cutting results, although there is the danger of melt dropping. Thistype of burner has therefore to be driven at maximum oxygen pressure to prevent nozzle blockage. The optimum forward sloping angle is 65-70 degrees, yielding a burn depth of 60-70 mm/m at a 1350 rpm/m.
Since continuous ignition can be guaranteed at speeds of up to 2000 mm/m. the limit for maximum possible cutting speed for 120 mm slabs was determined; this demonstrated that, in addition to the 1st (ignition) burner, further burners are needed to give higher speeds (+ 950 mm/m.)
Greater speeds (up to 1200 mm/m.) were also achieved simultaneously cutting from both above and below using up to 7 cutting nozzles at one time. The tests also showed that precise regulation of speed is also important otherwise wider joints may be produced and the rate will drop.
Basically, longitudinal cutting systems for fast cutting will consist of:
- slab/burner transporters with the facility to set exact cutting width and precise speed control;
- a carrying arm to give exact adjustment of lower and upper burner heads with additional protective devices against flames and melted waste;
- a combination burner with several nozzles for various media and the capacity to adjust individual nozzle angle;
- setting devices for combustion.
High speed cutting of a 9 m long, 600 deg. C hot slab, produced joints which were basically even and clean.
The traditional method of cutting steel slabs lengthwise is through autogenous flame-cutting. This is however a slow method taking some 50 min. per slab, and requiring that several cutters operate in parallel while the slabs are hot enough.

With the new high-temperature cutter, slabs can be cut - in practice divided - while still at melt-temperature, thereby saving the flame-cutting energy. This enables slabs to be divided length-wise in 6-7 min. depending on their lengths.

This is similar to a laminating-cutting process, although without energy losses caused by the need to cool the laminator and also with lower investment costs.

In the new process cutting occurs immediately and continuously while the slabs are still within a melt-temperature range. The divided slabs move then directly through an oven into the laminators saving a minimum of 150 deg. C of re-heating energy. The high-temperature cutting is performed by a combined beam consisting of gas, oxygen and a laser, with an operating speed matching the production speed of slabs.

Tests have shown that hot slabs could be cut at a speed of 1.2-1.7 m/min, hence justifying the building of a demonstration plant.

Ámbito científico (EuroSciVoc)

Este proyecto aún no se ha clasificado con EuroSciVoc.
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Programa(s)

• ENG-ENALT 2C - Programme (EEC) of demonstration projects relating to the exploitation of alternative energy sources and to energy saving and the substitution of hydrocarbons, 1983-1985

Tema(s)

• 3.2 - INDUSTRY

Convocatoria de propuestas

Datos no disponibles

Régimen de financiación

DEM - Demonstration contracts

Coordinador

Klöckner Stahl GmbH

• Aportación de la UE: Sin datos
• Dirección: Auf den Delben 35 ; 28237 Bremen ; Alemania
• Coste total: Sin datos