Manufacturing process
Manufacturing process
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Manufacturing Process
Global Steel Wire manufactures steel by recycling scrap, therefore contributing to environmental conservation. Its industrial process, which is completely ecological, uses scrap as its main raw material, melting it down in a steel mill with an electric furnace to obtain steel in the form of a semi-product called billet.
This billet is then transformed in a rolling mill into a wide range of different qualities of wire rod, which are used by our customers to manufacture products such as wires, strands, cables, meshes, steel ropes, springs, cold stamped screws or tyre reinforcement.
We have a PPE (Product and Process Engineering) department dedicated to research and development activities, which allows us to offer the most technologically advanced products – a key aspect in order to be able to compete in increasingly demanding markets.
The manufacturing process is outlined in these 4 steps:
1. Raw material: scrap
The metal load of each caster is made up of a mixture of selected scrap and pre-reduced ore pellets in order to obtain the appropriate residual element content according to the type of steel to be made.
The use of pre-reduced ore pellets allows very low levels of residual element content to be obtained, such as: Cr, Ni, Cu, Mo, Sn y N2.
Both scrap and pre-reduced products, as well as other raw materials (ferroalloys, fuels and slagging agents) are purchased in accordance with technical purchasing specifications from approved suppliers and are subject to periodic incoming goods inspections.
3. Rolling Mill
The process starts when 180 mm. square section billets weighing between 2,500 and 3,100 Kg enter the mill. They are heated in a walking beam furnace, water-cooled (walking beam), with a capacity of 170 Tm/h, with top and bottom heating.
Once hot, they are rolled in a 4-pass roughing mill (horizontal/vertical wire mill), to 140 mm square section billets.
These billets pass through a transfer unit and induction coils to superficially reheat the billets, recovering the temperature lost in the roughing process. After induction.
Line for diameters from 5.5 mm to 24 mm:
Passes to the preparatory and intermediate mill, with nodular cast iron rolls. The last 18 passes are made with tungsten carbide rolls in 3 mini-blocks with loop formers, 8-pass finishing blocks with automatic trimming scissors at their entry, and finally the 4-pass Reducing Sizing mills (RSM).
Having the RSM allows us to adjust the tolerance in ovality to +/- 0.10 mm, manufacturing diameters in the range of 5.5 mm to 24 mm and rolling at speeds of 105 m/s.
Before and after RSM we have control systems for the input and output section, with laser heads. We also have Eddy Current equipment for surface control of defects along the entire length of the roll.
The wire rod is then subjected to a water and air-controlled cooling process (Stelmor Optifl ex High Capacity), with optional use of the delayed cooling system (Retarded cooling). The entire cooling process is continuously controlled in a closed loop via computer.
The coils are formed vertically with an orbital coil distribution system.
Line for diameters from 25 mm to 52 mm:
Line connected to the “Garret” type intermediate mill. It has water boxes for rolling up to a temperature of 850°C, automatic scissors for trimming and sampling, Bar Reducing Sizing mill to obtain an ovality tolerance of +/-0.10 mm, the Garret winding machine, fans for cooling the coils, a walking beam conveyor and a transfer carriage to connect the coils to the compacting machines.
This production line is also equipped with two laser diameter gauges and an Eddy Current continuous defect control system.
Finally, the coils coming from the 2 lines are compacted by 40 Tm. presses and tied automatically with 4 wire rod ties of 6.5 mm. diameter.
2. Steelworks
The Steelworks consists of three main facilities:
An electric furnace, where the scrap and other raw materials used in the composition of the steel are melted. The diameter of the tank is 7.2 metres and it has a capacity of 150 tonnes. It has a 140 MVA transformer and the diameter of the electrodes is 600 mm. The liquid steel is poured using the EBT bottom pouring system, which prevents slag from escaping.
This liquid steel is poured into the ladle; where the next part of the process begins, the Cuhara Furnace, where the following tasks are carried out:
.White slag treatment at the beginning of the process.
.Adding the different ferroalloys to adjust the chemical composition.
.Flotation of the particles thanks to the porous plug at the base of the ladle.
.Liquid steel heating (by means of 3 electrodes) to transfer the liquid steel at the correct temperature to the Continuous Casting Machine.
The Continuous Casting Machine, where the steel is solidified and square section billets of 180 x 180 mm, 10 to 13 m long and weighing 2,500 to 3,250 kg are obtained.
The Continuous Casting Machine has six lines with 9.5 m radius. The Tundish capacity is 24 Tm, with 900 mm filling level. It is equipped with a cucharatundish and tundish-lingotera jet protection system by means of a submerged cover with a tundish slide lock. Electromagnetic agitation system in ingot mould, and automatic speed-temperature control system.
4. Treatments
All our wire rods can be supplied with annealing and/or stripping-coating treatments.
Annealing is carried out in an EBNER furnace with H2/N2 hydrogen atmosphere, following specific processes according to the type of steel.
The annealing processes that can be carried out with these furnaces are as follows:
.Subcritical anneals (softening and counter-acridising) below the lower critical temperature (720°C).
.Globular anneals above the lower critical temperature.
.Coercive anneals to remove magnetisation from the steel.
The wire rod, before annealing, is required to undergo a chemical pickling or shot blasting process, which means that, in its subsequent use, there is no problem of removing calamine.
STRIPPERCOATING:
We can supply ClH stripped wire rod with ClH coating as follows:
Phosphating + soap/polymer
Phosphate-free polymer
Phosphating + lime
Phosphating + passivation
1. Raw material: scrap
The metal load of each caster is made up of a mixture of selected scrap and pre-reduced ore pellets in order to obtain the appropriate residual element content according to the type of steel to be made.
The use of pre-reduced ore pellets allows very low levels of residual element content to be obtained, such as: Cr, Ni, Cu, Mo, Sn y N2.
Both scrap and pre-reduced products, as well as other raw materials (ferroalloys, fuels and slagging agents) are purchased in accordance with technical purchasing specifications from approved suppliers and are subject to periodic incoming goods inspections.
2. Steelworks
The Steelworks consists of three main facilities:
An electric furnace, where the scrap and other raw materials used in the composition of the steel are melted. The diameter of the tank is 7.2 metres and it has a capacity of 150 tonnes. It has a 140 MVA transformer and the diameter of the electrodes is 600 mm. The liquid steel is poured using the EBT bottom pouring system, which prevents slag from escaping.
This liquid steel is poured into the ladle; where the next part of the process begins, the Cuhara Furnace, where the following tasks are carried out:
.White slag treatment at the beginning of the process.
.Adding the different ferroalloys to adjust the chemical composition.
.Flotation of the particles thanks to the porous plug at the base of the ladle.
.Liquid steel heating (by means of 3 electrodes) to transfer the liquid steel at the correct temperature to the Continuous Casting Machine.
The Continuous Casting Machine, where the steel is solidified and square section billets of 180 x 180 mm, 10 to 13 m long and weighing 2,500 to 3,250 kg are obtained.
The Continuous Casting Machine has six lines with 9.5 m radius. The Tundish capacity is 24 Tm, with 900 mm filling level. It is equipped with a cucharatundish and tundish-lingotera jet protection system by means of a submerged cover with a tundish slide lock. Electromagnetic agitation system in ingot mould, and automatic speed-temperature control system.
3. Rolling Mill
The process starts when 180 mm. square section billets weighing between 2,500 and 3,100 Kg enter the mill. They are heated in a walking beam furnace, water-cooled (walking beam), with a capacity of 170 Tm/h, with top and bottom heating.
Once hot, they are rolled in a 4-pass roughing mill (horizontal/vertical wire mill), to 140 mm square section billets.
These billets pass through a transfer unit and induction coils to superficially reheat the billets, recovering the temperature lost in the roughing process. After induction.
Line for diameters from 5.5 mm to 24 mm:
Passes to the preparatory and intermediate mill, with nodular cast iron rolls. The last 18 passes are made with tungsten carbide rolls in 3 mini-blocks with loop formers, 8-pass finishing blocks with automatic trimming scissors at their entry, and finally the 4-pass Reducing Sizing mills (RSM).
Having the RSM allows us to adjust the tolerance in ovality to +/- 0.10 mm, manufacturing diameters in the range of 5.5 mm to 24 mm and rolling at speeds of 105 m/s.
Before and after RSM we have control systems for the input and output section, with laser heads. We also have Eddy Current equipment for surface control of defects along the entire length of the roll.
The wire rod is then subjected to a water and air-controlled cooling process (Stelmor Optifl ex High Capacity), with optional use of the delayed cooling system (Retarded cooling). The entire cooling process is continuously controlled in a closed loop via computer.
The coils are formed vertically with an orbital coil distribution system.
Line for diameters from 25 mm to 52 mm:
Line connected to the “Garret” type intermediate mill. It has water boxes for rolling up to a temperature of 850°C, automatic scissors for trimming and sampling, Bar Reducing Sizing mill to obtain an ovality tolerance of +/-0.10 mm, the Garret winding machine, fans for cooling the coils, a walking beam conveyor and a transfer carriage to connect the coils to the compacting machines.
This production line is also equipped with two laser diameter gauges and an Eddy Current continuous defect control system.
Finally, the coils coming from the 2 lines are compacted by 40 Tm. presses and tied automatically with 4 wire rod ties of 6.5 mm. diameter.
4. Treatments
All our wire rods can be supplied with annealing and/or stripping-coating treatments.
Annealing is carried out in an EBNER furnace with H2/N2 hydrogen atmosphere, following specific processes according to the type of steel.
The annealing processes that can be carried out with these furnaces are as follows:
.Subcritical anneals (softening and counter-acridising) below the lower critical temperature (720°C).
.Globular anneals above the lower critical temperature.
.Coercive anneals to remove magnetisation from the steel.
The wire rod, before annealing, is required to undergo a chemical pickling or shot blasting process, which means that, in its subsequent use, there is no problem of removing calamine.
STRIPPERCOATING:
We can supply ClH stripped wire rod with ClH coating as follows:
Phosphating + soap/polymer
Phosphate-free polymer
Phosphating + lime
Phosphating + passivation
