GB2569210A

GB2569210A - Steel profile and method of processing steel

Info

Publication number: GB2569210A
Application number: GB1812768.8A
Authority: GB
Inventors: Focchi Mauro; Gate Peter
Original assignee: British Steel PLC; Inoxihp SRL
Current assignee: British Steel PLC; Inoxihp SRL
Priority date: 2017-12-05
Filing date: 2017-12-05
Publication date: 2019-06-12
Anticipated expiration: 2037-12-05
Also published as: GB201812768D0; GB2569210B

Abstract

A hot rolled steel profile has a surface quality index of at least 6, preferably at least 7, more preferably at least 8. The surface quality index is defined according to a proportion, a distribution and a size of surface defects of the hot rolled steel profile. There may be no marks formed by rolled scale such as snake-skin, tiger scale, salt and pepper, comet, drag or banding. The profile may have a unit mass of 20-400 kg/m. The rolling reduction may be from 2:1 to 50:1. The profile may be a bulb-flat profile, a crane rail profile a forklift mast, hanger or fork profile, a track-shoe profile, a cathode-collector profile, a cutting edge profile, or a bull-wheel profile for a bull-wheel to drive a cable..

Description

Steel profile and method of processing steel

Field

The present invention relates to steel profiles and to methods of processing steel to form steel profiles. Particularly, the present invention relates to hot rolled steel profiles and to methods of processing steel to form hot rolled steel profiles.

Background to the invention

Generally, thermomechanical processing of steel is used to form profiles (also known as sections) from semi-finished casting products. Thermomechanical processing typically combines mechanical and/or plastic deformation processes, for example rolling, forging, extrusion, drawing and/or rotary piercing with thermal processes, for example heat-treatment, water quenching, controlled heating and/or cooling. Hot rolling is an example of thermomechanical processing and is primarily concerned with forming shapes and/or geometries of the profiles, rather than modifying microstructural properties of the steel, for example. In hot rolling, a semi-finished casting product is typically heated above its recrystallization temperature in air and plastically deformed between one or more sets of rolls. Hot rolling permits large deformations to be achieved with a low number of rolling cycles. Forging, for example cogging, is another example of thermomechanical processing and is primarily concerned with modifying microstructural properties of the steel, for example, while also changing a shape thereof.

Heating steel to such elevated temperatures in air results in formation of mill scale (also known as scale) on surfaces thereof. Scale is problematic since the scale may be pressed into the surface of the steel during subsequent forming and/or indent the steel during the subsequent forming. Hence, scale is typically removed by mechanical, thermal, hydraulic and/or chemical processing. For example, sheet and/or plate may be descaled using scalebreaker rolls, which flex the metal enough to fracture the scale. For example, blooms and/or billets may be descaled by water jetting. However, an efficiency of descaling may be relatively low, such that residual scale remains on the steel. The residual scale is similarly problematic since the residual scale may be pressed into the surface of the steel during subsequent forming and/or indent the steel during the subsequent forming, resulting in surface defects. The residual scale may be deleterious with respect to subsequent corrosion of the steel, since the residual scale is electro-chemically active (cathodic) with respect to the steel, thereby accelerating corrosion of exposed steel. Furthermore, the residual scale may be detrimental to corrosion protection coatings applied to the steel. For example, painted coatings may adhere poorly to the residual scale. In addition, the surface defects may result in quality control rejection of the steel.

Hence, there is a need to improve on efficiency of the descaling of steel.

Summary of the Invention

It is one aim of the present invention, amongst others, to provide a descaling apparatus and/or a method of processing steel which at least partially obviates or mitigates at least some of the disadvantages of the prior art, whether identified herein or elsewhere. For instance, it is an aim of embodiments of the invention to provide a descaling apparatus that improves an efficiency of descaling a heated, semi-finished steel product. For instance, it is an aim of embodiments of the invention to provide a method of processing steel that provides a semi-finished steel product having a reduced amount of residual scale. For instance, it is an aim of embodiments of the invention to provide a method of processing steel that provides a hot rolled steel profile having an improved surface quality. For instance, it is an aim of an embodiment of the invention to provide a hot rolled steel profile having an improved surface quality.

According to a first aspect, there is provided a descaling apparatus for descaling heated semifinished steel products by water jetting, the apparatus comprising:

a first set of rollers arranged to receive a heated semi-finished steel product thereon;

a set of sensors, arranged transversely to the first set of rollers, for sensing respective positions of opposed first and second surfaces of the heated semi-finished steel product;

a second set of rollers, arranged transversely to the first set of rollers, and arranged to guide the heated semi-finished steel product received on the first set of rollers by contacting at least one of the opposed first and second surfaces;

a first set of nozzles and an opposed second set of nozzles, arranged transversely to the first set of rollers, and arranged to jet water therethrough towards at least a part of the opposed first and second surfaces of the heated semi-finished steel product, respectively;

a water pump system arranged to pump water through the first set of nozzles and the second set of nozzles;

a controller arranged to determine a cross-sectional dimension of the heated semi-finished steel product based, at least in part, on the sensed respective positions of the opposed first and second surfaces;

wherein the apparatus is arrangeable in:

a first configuration, wherein the first set of nozzles and the opposed second set of nozzles are spaced apart; and a second configuration, wherein the first set of nozzles and the opposed second set of nozzles are spaced together;

wherein the controller is arranged to control the apparatus to move from the first configuration to the second configuration based, at least in part, on the determined cross-sectional dimension of the heated semi-finished steel product, whereby respective spacings of the first set of nozzles and the opposed second set of nozzles from the opposed first and second surfaces of the heated semi-finished steel product, respectively, are controlled.

According to a second aspect, there is provided a method of processing steel, the method comprising:

descaling a heated first semi-finished steel product by jetting water through at least a first set of nozzles towards at least a part of a first scale on a first surface thereof;

wherein descaling the heated first semi-finished steel product comprises: determining a first cross-sectional dimension of the heated first semi-finished steel product; controlling a first spacing of the first set of nozzles from the first surface based, at least in part, on the determined first cross-sectional dimension of the heated first semi-finished steel product; and descaling the heated first semi-finished steel product by jetting water through the first set of nozzles spaced apart from the first surface according to the controlled first spacing.

According to a third aspect, there is provided a method of processing steel, the method comprising:

receiving a first semi-finished steel product;

heating the first semi-finished steel product in air to a temperature of at least 1150 °C, whereby a first scale is formed on at least a first surface thereof; and descaling the heated first semi-finished steel product by jetting water through at least a first set of nozzles towards at least a part of the first scale on the first surface thereof;

According to a fourth aspect, there is provided a semi-finished steel product having a mass in a range from 3,000 to 19,000 kg and a cross-sectional area in a range from 80 cm² to 3000 cm², wherein the product has a scale on at most 3%, preferably at most 2%, more preferably at most 1% of a surface thereof and wherein a part of the scale has an area of at most 10 cm², preferably at most 8 cm², more preferably at most 6 cm², most preferably at most 5 cm².

According to a fifth aspect, there is provided a hot rolled steel profile having a surface quality index of at least 6, preferably at least 7, more preferably at least 8.

According to a sixth aspect, there is provided a semi-finished steel product formed according to the method of the second aspect.

According to a seventh aspect, there is provided a hot rolled steel profile formed according to the method of the second aspect.

According to an eighth aspect, there is provided a method of determining an amount of a scale on a heated semi-finished steel product.

According to an ninth aspect, there is provided a method of determining a surface quality index of a hot rolled steel profile.

Detailed Description of the Invention

According to the present invention there is provided a descaling apparatus, as set forth in the appended claims. Also provided is a method of processing steel, a semi-finished steel product and a hot rolled steel profile. Other features of the invention will be apparent from the dependent claims, and the description that follows.

Throughout this specification, the term “comprising” or “comprises” means including the component(s) specified but not to the exclusion of the presence of other components. The term “consisting essentially of’ or “consists essentially of” means including the components specified but excluding other components except for materials present as impurities, unavoidable materials present as a result of processes used to provide the components, and components added for a purpose other than achieving the technical effect of the invention, such as colourants, and the like.

The term “consisting of” or “consists of’ means including the components specified but excluding other components.

Whenever appropriate, depending upon the context, the use of the term “comprises” or “comprising” may also be taken to include the meaning “consists essentially of” or “consisting essentially of’, and also may also be taken to include the meaning “consists of’ or “consisting of’.

The optional features set out herein may be used either individually or in combination with each other where appropriate and particularly in the combinations as set out in the accompanying claims. The optional features for each aspect or exemplary embodiment of the invention, as set out herein are also applicable to all other aspects or exemplary embodiments of the invention, where appropriate. In other words, the skilled person reading this specification should consider the optional features for each aspect or exemplary embodiment of the invention as interchangeable and combinable between different aspects and exemplary embodiments.

According to the first aspect, there is provided a descaling apparatus for descaling heated semi-finished steel products by water jetting, the apparatus comprising:

wherein the apparatus is arrangeable in:

In this way, removal of scale from surfaces of heated semi-finished steel products is improved since respective spacings of the water jetting nozzles from the surfaces are controlled. By controlling these respective spacings, an efficiency of descaling may be increased such that an amount of residual scale remaining on the surfaces may be reduced. By reducing the residual scale remaining on the surfaces of the heated semi-finished steel products, surface defects resulting, at least in part, from the residual scale being pressed into the surfaces during subsequent forming processes, for example rolling and/or pressing, is reduced. Furthermore, by reducing scale remaining on the surfaces of the heated semi-finished steel products, spalling and/or transfer of this scale from the surfaces and/or accumulation of this scale in rolls and/or presses is reduced, thereby reducing surface defects resulting, at least in part, from the spalled, transferred and/or accumulated scale being pressed into the surfaces during subsequent forming processes, for example forging, rolling and/or pressing. In this way, surface qualities of the subsequently formed steel products is improved. In this way, quality control acceptance of the formed steel products is improved, resulting in reduced scrapping and/or remedial work of quality control rejected formed steel products.

In more detail, scale (also known as mill scale) forms on surfaces of steel heated in air. Scale comprises primarily magnetite, Fe₃O₄, having a blue-grey steely colour, typically together with a thin outer film of hematite, Fe₂O₃, being invisible to the naked eye. An inner portion of the magnetite usually includes fine metal grains and may also include an inner layer of residual wustite, FeO, between the magnetite and the steel and having a black colour. This inner portion contributes to a surface roughness of descaled metal. At elevated temperatures, FeO makes up about 85% of the scale thickness, Fe₃O₄ about 10 to 15% and Fe₂O₃ about 0.5 to 2%. During slow cooling below about 560°C, most of the FeO is transformed to Fe and Fe₃O₄, such that Fe₃O₄ is predominant after cooling. Scale is found on all hot-rolled steel products unless processed in a protective atmosphere or descaled. Scale is typically less than 0.1 mm thick and initially adheres to the steel surface, protecting the steel from atmospheric corrosion provided no breaks occur in the scale.

Semi-finished casting products

Generally, semi-finished casting products are intermediate castings, including ingots, blooms, billets, and slabs. Ingots are typically large castings, for storage and/or transportation. Blooms may be typically formed by rolling ingots down to smaller cross-sectional areas, of at least 36 in² (230 cm²). Billets have cross-sectional areas of at most 36 in² (230 cm²) and may be formed by hot rolling ingots and/or blooms. Additionally and/or alternatively, billets may be formed by continuous casting and/or extrusion. Slabs typically have rectangular cross-sections and are typically formed by continuous casting and/or by rolling ingots and/or blooms. In one example, the heated semi-finished steel product comprises and/or is an ingot, a bloom, a billet or a slab. In one preferred example, the heated semi-finished steel product is a bloom or a billet.

In one example, the cross-sectional dimension is in a range from 20 cm to 50 cm, preferably in a range from 25 to 45 cm, more preferably in a range from 28 to 40 cm.

In one example, the semi-finished steel product is cuboidal, having a length of at most 8 m, a width in a range from 20 cm to 50 cm and a height in a range from 15 cm to 60 cm. In one example, semi-finished steel product has a mass in a range from 3 T to 19 T kg, preferably in a range from 3 T to 9 T, more preferably in a range from 4 T to 9 T. In one example, semifinished steel product has a mass in a range from 3,000 to 19,000 kg, preferably in a range from 3,000 to 9,000 kg, more preferably in a range from 4,000 to 9,000 kg.

Temperature of heated semi-finished steel product

Generally, for hot working such as hot rolling or forging, semi-finished steel products are heated above their respective recrystallization temperatures (typically at least 60% of their respective melting points), such that the steel may recrystallize during deformation. In this way, the recrystallization keeps the steel from strain hardening, which thereby maintaining low yield strengths and hardnesses during hot working while ductilities remain high.

In one example, the heated semi-finished steel product is heated to a temperature of at least 1150 °C, preferably at least 1200 °C, more preferably at least 1225 °C, most preferably at least 1240 °C, for example 1250 °C.

In one example, the heated semi-finished steel product is heated to a temperature of at most 1350 °C, preferably at most 1300 °C, more preferably at most 1275 °C, most preferably at most 1260 °C, for example 1250 °C.

In one example, the heated semi-finished steel product is heated to a temperature in a range from 1150 °C to 1350 °C, preferably in a range from 1200 °C to 1300 °C, more preferably in a range from 1225 °C to 1275 °C, most preferably in a range from 1240 °C to 1260 °C, for example 1250 °C.

First set of rollers

The apparatus comprises the first set of rollers arranged to receive the heated semi-finished steel product thereon. In use, axes of the first set of rollers are arranged horizontally and the heated semi-finished steel product contacts respective upper regions ofthe first set of rollers. That is, the first set of rollers support, at least in part, the heated semi-finished steel product during descaling. In one example, the first set of rollers comprises a plurality of rollers, for example 2, 3, 4, 5, 6, 7, 8 or more rollers. In one example, axes ofthe first set of rollers are arranged mutually parallel and/or mutually coplanar and/or mutually aligned and/or mutually equispaced. In one example, a first roller ofthe first set of rollers is arranged on a first side of the first set of nozzles and the opposed second set of nozzles and a second roller ofthe first set of rollers is arranged on a second side thereof. In other words, one or more rollers of the first set of rollers are arranged before and after the water jetting nozzles, respectively. In this way, the heated semi-finished steel product may be supported on the first set of rollers during descaling. In one example, a first roller of the first set of rollers is a driven roller, arranged to be driven by an actuator, for example an electrical motor and/or a hydraulic motor. In this way, the heated semi-finished steel product may be moved to the apparatus from a previous processing step, through the apparatus for descaling and/or to a subsequent processing step. In one example, a second roller of the first set of rollers is an idler roller, arranged to freely rotate. Preferably, each roller of the first set of rollers is a driven roller. In one example, a first roller of the first set of rollers has a width greater than a maximum width of the heated semi-finished steel product. Preferably, each roller of the first set of rollers has such a width. In one example, a first roller of the first set of rollers is cylindrical. In one example, a first roller of the first set of rollers is cambered.

Sensors

The apparatus comprises the set of sensors, arranged transversely to the first set of rollers, for sensing respective positions of opposed first and second surfaces of the heated semi-finished steel product. In this way, the cross-sectional dimension of the heated semi-finished steel product may be determined, as described below. In one example, the sensed respective positions are distances between the opposed first and second surfaces and respective sensors of the set of sensors. In one example, a first sensor of the set of sensors is arranged to sense a position of the first side of the heated semi-finished steel product, for example by sensing a first distance of the first side of the heated semi-finished steel product from the first sensor. In one example, a second sensor of the set of sensors is arranged to sense a position of the second opposed side of the heated semi-finished steel product, for example by sensing a second distance of the second side of the heated semi-finished steel product from the second sensor. For example, the first sensor and the second sensor may be arranged to respectively sense positions of opposed lateral sides of the heated semi-finished steel product or opposed upper and lower sides of the heated semi-finished steel product. In one example, the first sensor and the second sensor may be arranged to respectively sense positions of opposed lateral sides of the heated semi-finished steel product. In one example, a first sensor of the set of sensors comprises and/or is a non-contact sensor. Non-contact sensors are preferred, since the heated semi-finished steel product is at an elevated temperature, as described above. Heat and/or electromagnetic radiation (EMR) emitted by the heated semifinished steel product may influence, at least in part, selection of suitable sensors. Suitable non-contact sensors include ultrasonic and optical distance sensors, such as laser distance sensors. Suitable laser distance sensors include Delta Dilas FT1500, such as FT1507-JL L=8M. Laser distance sensors are preferred, having millimetre accuracy. A plurality of such sensors may be provided. Additionally or alternatively, a dimension of the semi-finished steel product may be estimated using an array of sensors, the dimension being estimated according to which sensors sense the product.

In one example, a first sensor of the set of sensors is arranged to transmit a position, for example at rate of less than 1 Hz, 1 Hz, 5 Hz, 10 Hz, 20 Hz, 30 Hz or more. A transmission rate of less than 1 Hz is preferred, for example every 6 seconds. In this way, the controller may repeatedly determine the cross-sectional dimension of the heated semi-finished steel product.

In one example, the apparatus comprises at least one pivotable guide, preferably a pair of pivotable guides, arranged transversely to the first set of rollers and arranged to guide the heated semi-finished steel product by contacting at least one of the opposed first and second surfaces. A pair of pivotal guides may provide a funnel arrangement having a fixed mouth dimension and an adjustable throat dimension. The controller may be arranged to adjust the throat dimension, in use, to correspond to the cross-sectional dimension of the semi-finished product. In this way the heated, semi-finished steel product may be urged to a central location on the first set of rollers.

Second set of rollers

The apparatus comprises the second set of rollers, arranged transversely to the first set of rollers, and arranged to guide the heated semi-finished steel product received on the first set of rollers by contacting at least one of the opposed first and second surfaces. In this way, the second set of rollers guide the heated semi-finished steel product during descaling by rolling against a lateral side of the heated semi-finished steel product. For example, the second set of rollers may urge the heated semi-finished steel product centrally on the first set of rollers. Axes of the second set of rollers are arranged transversely, preferably orthogonally, to axes of the first set of rollers. In use, the axes of the second set of rollers are arranged vertically. In one example, the second set of rollers is arranged to guide the heated semi-finished steel product received on the first set of rollers by contacting the opposed first and second surfaces. In one example, a first roller of the second set of rollers is an idler roller, arranged to freely rotate. Preferably, each roller of the second set of rollers is an idler roller. In one example, a first roller of the first set of rollers has a width less than a maximum height of the heated semi-finished steel product. Preferably, each roller of the second set of rollers has such a width. In one example, a first roller of the second set of rollers is cylindrical. In one example, a first roller of the second set of rollers is cambered.

In one example, the second set of rollers comprises a first roller and an opposed second roller for contacting the opposed first and second surfaces respectively; and wherein the apparatus is arrangeable in:

the first configuration, wherein the first roller and the opposed second roller are spaced apart; and the second configuration, wherein the first roller and the opposed second roller are spaced together.

In this way, a spacing between the first roller and the opposed second roller may be controlled, so as to guide, for example centrally, heated semi-finished steel products having different cross-sectional dimensions, for example widths, through the descaling apparatus. In this way, an efficiency of descaling may be improved. The apparatus may further comprise an arrangement for guiding the hot bloom into a central position wherein pivoting guides are arranged to centrally funnel the bloom from the mouth formed by the first rollers into the aperture formed by the second rollers.

First and second sets of nozzles

The apparatus comprises the first set of nozzles and the opposed second set of nozzles, arranged transversely to the first set of rollers, and arranged to jet water therethrough towards at least a part of the opposed first and second surfaces of the heated semi-finished steel product, respectively. In this way, scale on the first and second surfaces may be removed simultaneously, as described previously. The first set of nozzles and the opposed second set of nozzles may be arranged vertically, in use, to jet water therethrough towards at least a part of opposed lateral surfaces of the heated semi-finished steel product.

In one example, the first set of nozzles comprises a plurality of nozzles, for example 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more nozzles. In one example, the plurality of nozzles of the first set of nozzles are mutually equispaced and/or mutually coplanar, such that a uniformity of descaling of the first surface is improved. In one example, the second set of nozzles comprises a plurality of nozzles, for example 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more nozzles. In one example, the plurality of nozzles of the second set of nozzles are mutually equispaced and/or mutually coplanar, such that a uniformity of descaling of the first surface is improved.

In other words, the nozzles may be arranged such that the long axes of the nozzles are mutually coplanar, or preferably the planes formed by the long axes of each set of nozzles may be parallel to, but offset from, the planes formed by each other set of nozzles. This offset arrangement may assist in avoiding nozzle entanglement when the nozzle sets are repositioned relative to the bloom surface.

In one example, the first set of nozzles is arranged, for example coupled to and/or provided by, a first header. In one example, the second set of nozzles is arranged, for example coupled to and/or provided by, a second header. The first header and/or the second header may be arranged to move, for example translate.

Suitable nozzles for jetting have nominal spray cones in a range from 20° to 50°, for example 22°, 26°, 30°, 34° or 40°. Suitable nozzles for jetting have equivalent bore diameters in a range from 1 mm to 6 mm. Suitable nozzles for jetting have alignments in a range from -15° to +15°. For example, each nozzle of the first set of nozzles may have an alignment of 0°. Alternatively, nozzles at one end of the first set of nozzles may have an alignment of-15° while nozzles at the other end of the first set of nozzles may have an alignment of+15°.

Suitable nozzles commercially available from Lechler Ltd (UK) include Series 6P4 SCALEMASTER® HP Superior nozzles, Series 6P3 MiniSCALEMASTER® HP Superior nozzles, Series 6PJ SCALEMASTER® HP Superior J-Type nozzles, Series 694 SCALEMASTER® nozzles, Series 682 SCALEMASTER® HP nozzles, Series 642 MiniSCALEMASTER® HP nozzles and Series 622 MicroSCALEMASTER® nozzles. Series 6P3 MiniSCALEMASTER® HP Superior nozzles are preferred, for example model 6P3.767.27.

The apparatus is arrangeable in:

the first configuration, wherein the first set of nozzles and the opposed second set of nozzles are spaced apart; and the second configuration, wherein the first set of nozzles and the opposed second set of nozzles are spaced together.

That is, the first set of nozzles and/or the opposed second set of nozzles are adjustable such that a spacing therebetween may be changed, for example controlled, as described below in more detail.

In this way, two opposed lateral surfaces of the heated semi-finished steel product may be descaled. Hence, in order to descale four lateral surfaces of the heated semi-finished steel product, the heated semi-finished steel product may be turned once 90° about its longitudinal axis and the descaling repeated after the turn, so as to descale the remaining two opposed lateral surfaces.

Alternatively, the apparatus may comprise a single set of nozzles, for example the first set of nozzles. Hence, in order to descale four lateral surfaces of the heated semi-finished steel product, the heated semi-finished steel product may be turned three times by 90° about its longitudinal axis and the descaling repeated after each turn.

Alternatively, as described below, the apparatus may comprise four sets of nozzles, enabling all four lateral surfaces of the heated semi-finished steel product to be descaled at the same time. In this way, processing efficiency is improved.

Water pump system

The apparatus comprises the water pump system arranged to pump the water through the first set of nozzles and the second set of nozzles. In one example, the water pump system is arranged to pump the water through a first nozzle of the first set of nozzles at a rate in a range from 10 L/min to 400 L/min and/or at a pressure in a range from 100 bar to 400 bar. In one example, the water pump system is arranged to pump the water through each nozzle of the first set of nozzles and the second set of nozzles at such rates and/or pressures.

In one example, the water has a pH of at least 7, a chloride content of at most 250 mg/kg and /or a chlorine content of at most 0.6 mg/kg. In this way, the chlorine/chloride, if present, may act as an antibacterial agent, thereby reducing blockage of nozzles otherwise caused by bacteria in the water. By controlling the chlorine/chloride levels to below the maximum levels set out, corrosion of the pipework of the water pumping system is reduced. Cameras may be used to monitor for nozzle blockage in use.

Controller

The apparatus comprises the controller arranged to determine the cross-sectional dimension, for example a width and/or a height, of the heated semi-finished steel product based, at least in part, on the sensed respective positions of the opposed first and second surfaces. In one example, the sensed respective positions are distances between the opposed first and second surfaces and respective sensors of the set of sensors. In one example, the controller is arranged to determine the cross-sectional dimension by calculation. For example, if a first distance between a first sensor of the set of sensors and the first surface is sensed as D1, a second distance between a second sensor of the set of sensors and the second surface is sensed as D2 and a third distance between the first sensor and the second sensor of the set of sensors is fixed as D12, then the cross-sectional dimension DO of the heated semi-finished steel product may be calculated by the controller to be DO = D12 - D1 - D2.

In one example, the controller is arranged to receive the sensed positions and/or distances from the first and second sensors of the set of sensors, for example a rate of less than 1 Hz, such as every 6 seconds, 1 Hz, 5 Hz, 10 Hz, 20 Hz, 30 Hz or more. In this way, the controller may repeatedly determine the cross-sectional dimension, for example a width and/or a height, of the heated semi-finished steel product.

The controller is arranged to control the apparatus to move from the first configuration to the second configuration based, at least in part, on the determined cross-sectional dimension of the heated semi-finished steel product, whereby respective spacings of the first set of nozzles and the opposed second set of nozzles from the opposed first and second surfaces of the heated semi-finished steel product, respectively, are controlled.

In this way, a spacing between the first set of nozzles and the opposed second set of nozzles may be controlled, for example adjusted according to the cross-sectional dimension of the heated semi-finished steel product. In this way, a first spacing between the first set of nozzles and the first surface of the heated semi-finished steel product and/or a second spacing between the opposed second set of nozzles and the second surface of the heated semifinished steel product may be controlled so as improve, for example optimise, jetting and hence descaling of the first surface and/or the second surface, respectively, of the heated semi-finished steel products. In this way, an efficiency of descaling of heated semi-finished steel products having different cross-sectional dimensions, for example widths, may be improved. For example, the respective efficiencies of descaling of two different heated semifinished steel products having different cross-sectional dimensions, for example widths, may be similar, for example the same since the spacings of the sets of nozzles from the respective surfaces are controlled to be similar, for example the same. In contrast, corresponding spacings for conventional descaling apparatuses are not controlled and/or not adjusted, such that efficiencies of descaling two different heated semi-finished steel products having different cross-sectional dimensions, for example widths, are different. For example, conventionally, an efficiency of descaling a first heated semi-finished steel product having a relatively smaller cross-sectional dimension, for example width, may be less than an efficiency of descaling a second heated semi-finished steel product having a relatively larger cross-sectional dimension, since an absolute position of a conventional set of nozzles is fixed.

Particularly, the efficiency of descaling may be determined, at least in part, by an impact pressure of the water on the scale and/or a thermal shock (i.e. rapid cooling) due to the water contacting the scale. The impact pressure may be dependent, at least in part, on appropriate nozzle selection combined with appropriate water flow rates and pressures. Furthermore, the impact pressure may be dependent, at least in part, on a spacing (also known as standoff distance) of a nozzle from the scale. Hence, by controlling the first spacing between the first set of nozzles and the first surface of the heated semi-finished steel product and/or the second spacing between the opposed second set of nozzles and the second surface of the heated semi-finished steel product, the impact pressure of the water may be controlled to be similar, for example the same, for heated semi-finished steel products having different cross-sectional dimensions, for example widths.

In one example, the controller is arranged to compare the determined cross-sectional dimension with a set of pre-determined cross-sectional dimensions. In one example, the controller is arranged to control the apparatus to move from the first configuration to the second configuration based, at least in part, on a result of the comparison. For example, the set of pre-determined cross-sectional dimensions may include nominal widths of expected semi-finished steel products and the determined cross-sectional dimension may be compared with these nominal widths, so as to identify a type of the semi-finished steel product, for example.

In one example, the controller is arranged to selectively control the apparatus to move from the first configuration to the second configuration based, at least in part, on an error condition caused by the determined cross-sectional dimension of the heated semi-finished steel product. For example, if the controller determines that the determined cross-sectional dimension of the heated semi-finished steel product is greater or less than an expected cross-sectional dimension by a pre-determined amount, for example 10 mm, preferably 25 mm, more preferably 50 mm, the controller may determine that the heated semi-finished steel product is over-width or under-width, respectively. If the controller determines that the heated semifinished steel product is over-width or under-width, the controller may selectively control the apparatus to remain in the first configuration, wherein the first set of nozzles and the opposed second set of nozzles are spaced apart. In this way, the controller may prevent damage to the apparatus caused by up-turned blooms, for example. Conversely, if the controller determines that the determined cross-sectional dimension of the heated semi-finished steel product is within a pre-determined amount, for example 10 mm, preferably 25 mm, more preferably 50 mm, of the expected cross-sectional dimension, the controller may selectively control the apparatus to move from the first configuration to the second configuration.

In one example, the controller is arranged to control the apparatus to move from the first configuration to the second configuration wherein a first spacing of the first set of nozzles from the first surface and/or a second spacing of the second set of nozzles from the second surface is in a range from 60 mm to 160 mm, preferably in a range from 85 to 135 mm, more preferably in a range from 100 mm to 120 mm, for example 110 mm. It should be understood that the first spacing of the first set of nozzles from the first surface is defined as a distance from a nozzle tip (also known as mouthpiece) of a first nozzle of the first set of nozzles to the first surface, measured orthogonally thereto. Spacings of each of the nozzles of the first set of nozzles may be the same, for example nominally the same. The second spacing is defined similarly.

In one example, the controller is arranged to control a pumping speed of the pumping system based, at least in part, on the determined cross-sectional dimension of the heated semifinished steel product. For example, the controller may be arranged to increase the pumping speed in response to determination of the cross-sectional dimension of the heated semifinished steel product i.e. indicating that the heated semi-finished steel product is received on the first set of rollers. For example, the controller may be arranged to decrease the pumping speed in response to determination of no cross-sectional dimension of the heated semifinished steel product i.e. indicating that the heated semi-finished steel product is not received on the first set of rollers.

Third set of nozzles

In one example, the apparatus comprises: a third set of nozzles, opposed to the first set of rollers, arranged transversely to the first and second set of nozzles, and arranged to jet water therethrough towards at least a part of a third surface, transverse to the first and second surfaces of the heated semi-finished steel product; wherein the water pump system is arranged to pump water through the third set of nozzles; and wherein the apparatus is arrangeable in:

the first configuration, wherein the third set of nozzles and the first set of rollers are spaced apart; and the second configuration, wherein the third set of nozzles and the first set of rollers are spaced together.

In this way, the third surface of the heated semi-finished steel product may be descaled simultaneously with the descaling of the first and second surfaces. In use, the third surface may be the upper, horizontal surface of the heated semi-finished steel product. Hence, the third set of nozzles may be arranged horizontally so as to jet water downwards, in use.

In one example, the third set of nozzles is arranged to move, for example translate, relative to the first set of rollers. In this way, an efficiency of descaling of heated semi-finished steel products having different heights may be improved.

In one example, the controller is arranged to control the apparatus to move from the first configuration to the second configuration wherein a third spacing of the third set of nozzles from the third surface is in a range from 80 mm to 190 mm, preferably in a range from 105 to

165 mm, more preferably in a range from 120 mm to 150 mm, for example 135 mm. The third spacing is defined similarly to the first spacing. The third spacing may be relatively greater than the first spacing and/or the second spacing.

The third set of nozzles may be otherwise as described with respect to the first set of nozzles. The water pump system may be arranged for the third set of nozzles similarly as described with respect to the first set of nozzles.

In one example, the first set of nozzles is mechanically coupled to the third set of nozzles thereby defining a first plane. In this way, the first set of nozzles and the third set of nozzles are moved together, for example vertically and/or horizontally, in use. In this way, actuation and/or control of movement is simplified.

Fourth set of nozzles

In one example, the apparatus comprises:

a fourth set of nozzles, arranged transversely to the first and second set of nozzles, and arranged to jet water therethrough towards at least a part of a fourth surface, transverse to the first and second surfaces of the heated semi-finished steel product; and wherein the water pump system is arranged to pump water through the fourth set of nozzles.

In this way, the fourth surface of the heated semi-finished steel product may be descaled simultaneously with the descaling of the first and second surfaces. In use, the fourth surface may be the lower, horizontal surface of the heated semi-finished steel product. Hence, the fourth set of nozzles may be arranged horizontally so as to jet water upwards, in use.

In one example, the fourth set of nozzles is arranged between adjacent rollers of the first set of rollers. In one example, a position of the fourth set of nozzles is fixed such that a fourth spacing between the fourth set of nozzles and the fourth surface is constant, in use. The fourth spacing may be relatively greater or less than the first spacing and/or the second spacing.

The fourth set of nozzles may be otherwise as described with respect to the first set of nozzles. The water pump system may be arranged for the fourth set of nozzles similarly as described with respect to the first set of nozzles.

In one example, the second set of nozzles is mechanically coupled to the fourth set of nozzles thereby defining a second plane. In this way, the second set of nozzles and the fourth set of nozzles are moved together, for example horizontally, in use. In this way, actuation and/or control of movement is simplified.

In one example, the first set of nozzles and the second set of nozzles are coplanar, for example arranged in a same vertical plane, in use. In one example, the first first set of nozzles and the second set of nozzles are arranged in mutually parallel vertical planes, which are not coplanar, in use.

In one example, the first set of nozzles is mechanically coupled to the third set of nozzles thereby defining a first plane, the second set of nozzles is mechanically coupled to the fourth set of nozzles thereby defining a second plane, and the first set of nozzles and the second set of nozzles are arranged in mutually parallel vertical planes, in use i.e. the first plane and the second plane are mutually parallel but not coplanar. In this way, collision between the sets of nozzles during movement thereof, between the first configuration and the second configuration, is avoided.

Method of processing steel - descaling

According to the second aspect, there is provided a method of processing steel, the method comprising:

The first set of nozzles, the first spacing, the jetting and the water may be as described with respect to the first aspect.

The heated first semi-finished steel product, the first scale, the first surface and the first crosssectional dimension may be as described with respect to the heated semi-finished steel product, the scale, the first surface and the cross-sectional dimension of the first aspect, respectively.

The method may include any of the steps as described with respect to the first aspect.

In one example, the method comprises:

descaling a heated second semi-finished steel product by jetting water through at least the first set of nozzles towards at least a part of a second scale on a second surface thereof;

wherein descaling the heated second semi-finished steel product comprises: determining a second cross-sectional dimension of the heated second semi-finished steel product;

controlling a second spacing ofthe first set of nozzles from the second surface based, at least in part, on the determined second cross-sectional dimension of the heated second semifinished steel product; and descaling the heated second semi-finished steel product by jetting water through the first set of nozzles spaced apart from the second surface according to the controlled second spacing; wherein the second cross-sectional dimension and the first cross-sectional dimension are different; and wherein the controlled second spacing corresponds with the controlled first spacing.

That is, the controlled second spacing is substantially equal to the controlled first spacing, despite a difference between the second cross-sectional dimension and the first crosssectional dimension, such that an efficiency of descaling the second semi-finished steel product is substantially equal to an efficiency of descaling the first semi-finished steel product.

In one example, a difference between the controlled second spacing and the controlled first spacing is at most 50 mm, preferably at most 40 mm, more preferably at most 30 mm, most preferably at most 25 mm.

Method of processing steel - forming

According to the third aspect, there is provided a method of processing steel, the method comprising:

receiving a first semi-finished steel product;

heating the first semi-finished steel product in air to a temperature of at least 1150 °C, whereby a first scale is formed on at least a first surface thereof; and descaling the heated first semi-finished steel product by jetting water through at least a first set of nozzles towards at least a part ofthe first scale on the first surface thereof;

wherein descaling the heated first semi-finished steel product comprises: determining a first cross-sectional dimension ofthe heated first semi-finished steel product; controlling a first spacing ofthe first set of nozzles from the first surface based, at least in part, on the determined first cross-sectional dimension of the heated first semi-finished steel product; and descaling the heated first semi-finished steel product by jetting water through the first set of nozzles spaced apart from the first surface according to the controlled first spacing.

In this way, an efficiency of descaling of heated first semi-finished steel products having different cross-sectional dimensions, for example widths, may be improved, as described above with respect to the first aspect. Particularly, a surface quality of the second semifinished steel product may be improved since the first semi-finished steel product is descaled efficiently prior to forging, as described above with respect to the first aspect, since the first set of nozzles are spaced apart from the first surface according to the controlled first spacing.

The first semi-finished steel product, the heated first semi-finished steel product, the temperature, the first scale, the first surface and the first cross-sectional dimension may be as described with respect to the semi-finished steel product, the heated semi-finished steel product, the temperature, the scale, the first surface and the cross-sectional dimension of the first aspect, respectively.

In one example of this aspect, the method may further include providing a plurality of heated second semi-finished steel products by rolling the descaled, heated first semi-finished steel product and dividing the rolled, descaled, heated first semi-finished steel product into the plurality of heated second semi-finished steel products.

By providing relatively larger first semi-finished steel products and forming relatively smaller second semi-finished steel products therefrom, a manufacturing efficiency may be improved and/or a cost reduced.

The forging may be as described with respect to the first aspect. Generally, types of forging includes roll forging, swaging, cogging, open-die forging, impression-die forging, press forging, automatic hot forging and upsetting. In one example, the forging comprises and/or is cogging. In one example, dividing comprises dividing into 1 to 5, preferably 2 to 4, heated second semifinished steel products.

In one example, dividing the forged, descaled, heated first semi-finished steel product comprises shearing the forged, descaled, heated first semi-finished steel product. For example, the forged, descaled, heated first semi-finished steel product may be sheared longitudinally and/or transversely.

In one example, the method comprises:

reheating a heated second semi-finished steel product of the plurality of second semi-finished steel products in air to a temperature of at least 1150 °C, whereby a second scale is formed on at least a second surface thereof;

descaling the reheated second semi-finished steel product by jetting water through at least the first set of nozzles towards at least a part of the second scale on the second surface thereof; and providing a hot rolled steel profile by rolling the descaled, reheated second semi-finished steel product;

wherein descaling the reheated second semi-finished steel product comprises: determining a second cross-sectional dimension of the reheated second semi-finished steel product;

controlling a second spacing of the first set of nozzles from the second surface based, at least in part, on the determined second cross-sectional dimension of the reheated second semifinished steel product; and descaling the reheated second semi-finished steel product by jetting water through the first set of nozzles spaced apart from the second surface according to the controlled second spacing.

In this way, an efficiency of descaling of heated second semi-finished steel products having different cross-sectional dimensions, for example widths, may be improved, as described above with respect to the first aspect. By providing relatively larger first semi-finished steel products, forming relatively smaller second semi-finished steel products therefrom and in turn, forming the hot rolled steel profile therefrom, a manufacturing efficiency may be improved and/or a cost reduced. Particularly, a surface quality of the hot rolled steel profile may be improved since the second semi-finished steel product is descaled efficiently prior to rolling, as described above with respect to the first aspect, since the first set of nozzles are spaced apart from the second surface according to the controlled second spacing.

In one example, the method comprises heating the first semi-finished steel product in a first furnace. In one example, the method comprises reheating the second semi-finished steel product in a second furnace (also known as interfurnace). In one example, the method comprises moving the heated second semi-finished steel product to the second furnace.

In one example, the first cross-sectional dimension is in a range from 20 cm to 50 cm, preferably in a range from 25 to 45 cm, more preferably in a range from 28 to 40 cm.

In one example, the received first semi-finished steel product is cuboidal, having a length of at most 8 m, a width in a range from 20 cm to 50 cm and a height in a range from 15 cm to 60 cm. In one example, first semi-finished steel product has a mass in a range from 3 T to 19 T kg, preferably in a range from 3 T to 9 T, more preferably in a range from 4 T to 9 T. In one example, first semi-finished steel product has a mass in a range from 3,000 to 19,000 kg, preferably in a range from 3,000 to 9,000 kg, more preferably in a range from 4,000 to 9,000 kg.

In one example, determining the first cross-sectional dimension of the heated first semifinished steel product comprises:

sensing respective positions of the first surface and an opposed surface thereto of the heated semi-finished steel product; and determining the first cross-sectional dimension of the heated first semi-finished steel product based, at least in part, on the sensed respective positions of the first surface and the opposed surface.

In one example, descaling the heated first semi-finished steel product is by jetting water through a plurality of sets of nozzles towards a respective plurality of surfaces of the heated first semi-finished steel product.

In one example, the method comprises controlling respective spacings of at least two of the plurality of sets of nozzles from at least two of the respective plurality of surfaces based, at least in part, on the determined first cross-sectional dimension of the heated first semi-finished steel product.

In one example, descaling the heated first semi-finished steel product by jetting water through the first set of nozzles spaced apart from the first surface according to the controlled first spacing comprises moving the heated first semi-finished steel product through the jetted water at a speed in a range from 0.1 ms'¹ to 10 ms'¹, preferably in a range from 0.5 ms'¹to 5 ms'¹, more preferable in a range from 0.75 ms'¹ to 2.5 ms'¹, for example 1 ms'¹.

In one example, the descaled, heated first semi-finished steel product has a scale on at most 1%, preferably at most 0.1%, more preferably at most 0.01% by area of a surface thereof and/or wherein a part of the scale has an area of at most 10 cm², preferably at most 8 cm², more preferably at most 6 cm², most preferably at most 5 cm² and/or wherein a part of the scale has a thickness of at most 0.5 mm, preferably at most 0.4 mm, more preferably at most 0.3 mm. In this way, an amount of residual scale remaining on the descaled, heated first semifinished steel product is reduced such that degradation of surface quality due, at least in part, to the residual scale during forging is reduced. In this way, a surface quality of the hot rolled steel profile is improved.

In one example, the descaled, heated second semi-finished steel product has a scale on at most 1%, preferably at most 0.1%, more preferably at most 0.01% by area of a surface thereof and/or wherein a part of the scale has an area of at most 10 cm², preferably at most 8 cm², more preferably at most 6 cm², most preferably at most 5 cm² and/or wherein a part of the scale has a thickness of at most 0.5 mm, preferably at most 0.4 mm, more preferably at most 0.3 mm. In this way, an amount of residual scale remaining on the descaled, heated second semi-finished steel product is reduced such that degradation of surface quality due, at least in part, to the residual scale during rolling is reduced. In this way, a surface quality of the hot rolled steel profile is improved.

In one example, the hot rolled steel profile has a surface quality index of at least 6, preferably at least 7, more preferably at least 8.

The surface quality index may be defined according to a proportion, a distribution and a size of surface defects (also known as discontinuities) of the hot rolled steel profile, as shown in Table 1. Rolled in scale may result in surface defects including ‘snake skin effect’, ‘tiger scale’, ‘salt and pepper’, ‘drag or comet’ and/or banding defects.

Surface quality index	Area of surface defects as a percentage of total surface area	Distribution of surface defects	Depth of surface defects	Comments
10	At most 0.1%	Uniform	At most 0.2 mm	No scale marks
9	At most 1 %	Uniform	At most 0.2 mm
8	At most 2%	Uniform	At most 0.3 mm
7	At most 3.5%	Uniform	At most 0.3 mm
6	At most 5%	Uniform	At most 0.3 mm
5	At most 7.5%	Uniform	At most 0.3 mm
4	At most 10%	Uniform	At most 0.5 mm
3	At most 15%	Uniform	At most 0.5 mm
2	At most 20%	Uniform	At most 0.5 mm
1	More than 20%	Uniform	At most 0.5 mm
0	More than 5%	Banding	At most 0.5 mm

Table 1: Surface quality index

According to the fourth aspect, there is provided a semi-finished steel product having a mass in a range from 3,000 to 19,000 kg and a cross-sectional area in a range from 300 cm² to 3000 cm², wherein the product has a scale on at most 1%, preferably at most 0.1%, more preferably at most 0.01% by area of a surface thereof and/or wherein a part of the scale has an area of at most 10 cm², preferably at most 8 cm², more preferably at most 6 cm², most preferably at most 5 cm² and/or wherein a part of the scale has a thickness of at most 0.5 mm, preferably at most 0.4 mm, more preferably at most 0.3 mm.

By providing relatively larger semi-finished steel products and forming relatively smaller semifinished steel products therefrom, a manufacturing efficiency may be improved and/or a cost reduced. Particularly, a surface quality of the semi-finished steel product may be improved since the semi-finished steel product is descaled efficiently prior to subsequent hot working, as described above with respect to the first aspect.

According to the fifth aspect, there is provided a hot rolled steel profile having a surface quality index of at least 6, preferably at least 7, more preferably at least 8.

It should be understood that the hot rolled steel profile is assessed as hot rolled (also known as as-received) - i.e. before and subsequent surface treatment and/or machining.

The surface quality index may be as described with respect to the third aspect.

In this way, quality control acceptance of the hot rolled steel profile is improved, resulting in reduced scrapping and/or remedial work of quality control rejected hot rolled steel profiles. Surface quality may be particularly important for hot rolled steel profiles included in vehicles, quality control acceptance of which is relatively more demanding. Furthermore, adhesion of and/or protection due to surface coatings applied to the hot rolled steel profile is improved, resulting in improved protection and/or surface finish, as described previously.

In one example the hot rolled steel profile has a unit mass of at least 20 kg/m, at least 30 kg/m, or at least 40 kg/m.

In one example, the hot rolled steel profile has a unit mass of at most 400 kg/m, at most 300 kg/m, or at most 270 kg/m, for example 260 kg/m.

In one example, the hot rolled steel profile has a symmetrical cross-section, having at least one line of symmetry. In one example, the hot rolled steel profile has an asymmetrical crosssection, having no lines of symmetry.

In one example, the hot rolled steel profile is formed by a rolling reduction ratio in a range from 2:1 to 50:1, preferably in a range from 3:1 to 27:1.

In one example, the hot rolled steel profile is a bulb flat profile, a crane rail profile, a forklift profile, a track shoe profile, a cathode collector bar profile, a cutting edge profile, a top hat profile, a conveyor channel section or a bull wheel profile.

Generally, bulb flats are used for plate stiffening, having widths in a range from 100 mm to 430 mm, thicknesses in a range from 7 mm to 20 mm and lengths in a range from 6 m to 18 m. Grades of steel for bulb flats include normal strength grades A, B, D and E and high strength grades A32, D32, E32, A36, D36 and E36. Grades of steel for bulb flats also include ASTM grade A572 Gr50, EN10025-2 grades S235JR+AR, S235J0+AR, S235J2+AR, S275JR+AR, S275J0+AR, S275J2+AR, S355JR+AR, S355J0+AR and S355J2+AR, EN10025-4 grade S355M and EN10225 grades G11 and G12.

Generally, crane rail is used for overhead gantry and floor-mounted cranes in ports, warehouses and shipyards. Grades of steel for crane rail may be according to DIN 536-1, for example 690, 880 and 90V, as shown in Table 2.

Grade	wt.%	C	Si	Mn	P	S	V
690	Min	0.40	-	0.80	-	-	-
Max	0.60	0.35	1.20	0.045	0.045	-
880	Min	0.60	-	0.80	-	-	-
Max	0.80	0.50	1.30	0.045	0.045	-
90V	Min	0.50	-	0.80	-	-	0.06
Max	0.70	0.50	1.40	0.030	0.030	0.20
110CrV	Min	0.05	-	0.80	-	-	-
Max	1.00	0.50	1.00	0.30	0.30	1.00

Table 2: Compositions of steels for crane rail (ladle analysis)

Generally, forklift profiles include profiles for mast assemblies, for example mast profiles (including U, I, J and offset J profiles), carriage (also known as hanger) bar profiles and flats for manufacturing fork arms.

Generally, track shoe profiles include single, double and triple grouser (spike) designs, having widths in a range from 170 mm to over 350 mm. Grades of steel for track shoe profiles include standard steels, for example boron-treated steels having a nominal carbon content of 0.3 wt.% and optionally Cr in a range from 0 to 0.50 wt.% such as C30Cr0, C30Cr15, C30Cr50 and lower carbon steels, for example boron-treated steels having low sulphur (LS) and/or a lower carbon content of 0.25 wt.% and optionally Cr in a range from 0 to 0.75 wt.% such as C25Cr10, C25Cr40, C25Cr45-LS and C25Cr75-LS.

Generally, cathode collector bars have section widths in a range from 122 mm to 279 mm, thicknesses in a range from 90 mm to 160 mm and cold-sawn lengths in a range from 1.5 m to 10 m. Steel grades for cathode collector bars include ultra low carbon grades, having improved resistivity compared with other grades.

Generally, cutting edge profiles provide additional wear resistance and extended life for excavator bucket applications and include single bevel flats, double bevel flats, grader bars and arrowhead flats. Grades of steel for cutting edge profiles include standard boron-treated steels having a nominal carbon content of 0.3 wt.% such as SK-15-A, SK-15-B and SK-15-C and lower carbon boron-treated steels having a lower nominal carbon content of 0.25 wt.% such as SK1335K, SK1341K and SK1361K. Grades of steel for arrowhead flats include SK1335K and 41B18M. Non-heat treated grades of steel for cutting edge profiles include SAE1572, SAE1084 and SAE1084.

Generally, mining profiles include tophat shaft guide sections for guiding cages and skips in mine shafts and conveyor channel sections used for manufacturing long wall or chain conveyors. Grades of steel for mining profiles include EN 10025-2: 2004 grades S275J0+AR, S355JR+AR and S355J2+AR, SANS grades 50025-2: 2009 S275J0+AR, S355JR+AR and S355J2+AR, CSA grades G40.21-04: 2004, 300W, 350W and 350WT and AS/NZS 3679.1 grade 350.

Generally, bull wheel profiles may be used for bull wheels to drive cables, such as cables on ski-lifts or cablecars for example.

According to the sixth aspect, there is provided a semi-finished steel product formed according to the method of the second aspect.

According to the seventh aspect, there is provided a hot rolled steel profile formed according to the method of the second aspect.

According to the eighth aspect, there is provided a method of determining an amount of a scale on a heated semi-finished steel product. The method may comprise acquiring an image of the heated semi-finished steel product and may comprise analysing the acquired image to determine the amount of scale.

According to the ninth aspect, there is provided a method of determining a surface quality index of a hot rolled steel profile. The method may comprise acquiring an image of the heated semi-finished steel product and may comprise analysing the acquired image to determine the surface quality index. The surface quality index may be assessed as described in relation to the third aspect wet out hereinbefore.

Brief description of the drawings

For a better understanding of the invention, and to show how exemplary embodiments of the same may be brought into effect, reference will be made, by way of example only, to the accompanying diagrammatic Figures, in which:

Figure 1 schematically depicts a descaling apparatus according to an exemplary embodiment;

Figures, 2A and 2B schematically depict partial cross-sections through the descaling apparatus of Figure 1, in use;

Figure 3 schematically depicts a part of a steel mill including the descaling apparatus of Figure 1;

Figure 4 schematically depicts another part of the steel mill including another descaling apparatus of Figure 1;

Figure 5 schematically depicts a method of processing steel according to an exemplary embodiment;

Figure 6 schematically depicts a method of processing steel according to an exemplary embodiment;

Figure 7 schematically depicts a method of processing steel according to an exemplary embodiment;

Figures 8A and 8B schematically depict semi-finished steel products having scale on surfaces thereof;

Figures 9A to 9C are photographs of heated semi-finished steel products having scale on surfaces thereof and Figure 9D is a photograph of a heated semi-finished steel product according to an exemplary embodiment;

Figure 10 schematically depicts a surface quality index of a hot rolled steel profile;

Figures 11 A, 11B and 11C are photographs of hot rolled steel profiles having surface defects in surfaces thereon

Figures 12 is a photograph of a hot rolled steel profile according to an exemplary embodiment;

Figures 13A is a photograph of a hot rolled steel profile having surface defects in a surface thereof and Figure 13B is a photograph of a hot rolled steel profile according to an exemplary embodiment;

Figure 14 schematically depicts a cross-section of a bulb flat according to an exemplary embodiment;

Figure 15 schematically depicts a cross-section of a crane rail according to an exemplary embodiment;

Figures 16A to 16C schematically depict cross-sections of track shoe profiles according to exemplary embodiments;

Figures 17A to 17D schematically depict cross-sections of cutting edge profiles according to exemplary embodiments;

Figure 18 schematically depicts a cross-sections of a top hat profile according to exemplary embodiment.

Detailed Description of the Drawings

Figure 1 schematically depicts a descaling apparatus 10 according to an exemplary embodiment. Figures 2A and 2B schematically depict partial cross-sections through the descaling apparatus of Figure 1 in use.

The descaling apparatus 10 is for descaling heated semi-finished steel products by water jetting. The apparatus 10 comprises a first set of rollers 100 (100A - 100E) arranged to receive a heated semi-finished steel product P thereon. The apparatus 10 comprises a set of sensors 200 (200A - 200E), not shown, arranged transversely to the first set of rollers 100, for sensing respective positions of opposed first and second surfaces S1 - S2 of the heated semi-finished steel product P. The apparatus 10 comprises a second set of rollers 300 (300A - 300D), arranged transversely to the first set of rollers 100, and arranged to guide the heated semifinished steel product P received on the first set of rollers 100 by contacting at least one of the opposed first and second surfaces S1 - S2. The apparatus 10 comprises a first set of nozzles 400A and an opposed second set of nozzles 400B, arranged transversely to the first set of rollers 100, and arranged to jet water therethrough towards at least a part of the opposed first and second surfaces S1 - S2 of the heated semi-finished steel product P, respectively. The apparatus 10 comprises a water pump system 500 arranged to pump water through the first set of nozzles 400A and the second set of nozzles 400B. The apparatus 10 comprises a controller 600 (not shown) arranged to determine a cross-sectional dimension DO of the heated semi-finished steel product P based, at least in part, on the sensed respective positions of the opposed first and second surfaces S1 - S2. The apparatus 10 is arrangeable in a first configuration, wherein the first set of nozzles 400A and the opposed second set of nozzles 400B are spaced apart. The apparatus 10 is arrangeable in a second configuration, wherein the first set of nozzles 400A and the opposed second set of nozzles 400B are spaced together. The controller 600 is arranged to control the apparatus 10 to move from the first configuration to the second configuration based, at least in part, on the determined crosssectional dimension DO of the heated semi-finished steel product P, whereby respective spacings s1 & s2 of the first set of nozzles 400A and the opposed second set of nozzles 400B from the opposed first and second surfaces S1 & S2 of the heated semi-finished steel product P, respectively, are controlled.

In this way, removal of scale from surfaces of heated semi-finished steel products is improved since respective spacings of the water jetting nozzles from the surfaces are controlled. This is particularly advantageous for heated semi-finished steel products having different crosssectional dimensions, as described previously.

The apparatus 10 comprises the first set of rollers 100 arranged to receive the heated semifinished steel product P thereon. In use, axes of the first set of rollers 100 are arranged horizontally and the heated semi-finished steel product P contacts respective upper regions of the first set of rollers 100. In this example, the first set of rollers 100 comprises five rollers 100A - 100E (i.e. a plurality of rollers). In this example, axes of the first set of rollers 100 are arranged mutually parallel, mutually coplanar and mutually aligned. In this example, axes of the first set of rollers 100 are not mutually equispaced. In this example, a first roller 100Α of the first set of rollers 100 is arranged on a first side A of the first set of nozzles 400Α and the opposed second set of nozzles 400B and a second roller 100E of the first set of rollers 100 is arranged on a second side B thereof. In this example, the two rollers 100Α - 100B of the first set of rollers 100 are arranged before the water jetting nozzles 400Α - 400B and the three rollers 100C - 100E of the first set of rollers 100 are arranged after the water jetting nozzles 400Α - 400B. In this example, each roller 100Α - 100E of the first set of rollers 100 is a driven roller. In this example, each roller 100A - 100E of the first set of rollers 100 is cylindrical, having a diameter of 400 mm, and a width of 1200 mm and thus greater than a maximum expected width ofthe semi-finished steel product P.

The apparatus 10 comprises the set of sensors 200, arranged transversely to the first set of rollers 100, for sensing respective positions of opposed first and second surfaces S1 - S2 of the heated semi-finished steel product P. In this example, the sensed respective positions are distances between the opposed first and second surfaces S1 - S2 and respective sensors 200A - 200B of the set of sensors 200. In this example, the first sensor 200A of the set of sensors 200 is arranged to sense a position ofthe first surface S1 ofthe heated semi-finished steel product P by sensing a first distance D1 of the first surface S1 of the heated semifinished steel product P from the first sensor 200A. In this example, the second sensor 200B of the set of sensors 200 is arranged to sense a position ofthe second opposed side S2 ofthe heated semi-finished steel product P by sensing a second distance D2 ofthe second surface S2 of the heated semi-finished steel product from the second sensor 200B. In this example, the first sensor 200A and the second sensor 200B are arranged to respectively sense positions of opposed lateral surfaces S1 - S2 ofthe heated semi-finished steel product. In this example, the first sensor 200A ofthe set of sensors 200 is a non-contact sensor, specifically a laser distance sensor, having millimetre accuracy. Five (i.e. a plurality) of such sensors 200A 200E are provided. The sensors 200A to 200E are Delta Dilas FT1507-JC L=8M

In this example, the first sensor 200A of the set of sensors 200 is arranged to transmit a position ofthe first surface S1 every 6 seconds.

The apparatus 10 comprises the second set of rollers 300, arranged transversely to the first set of rollers 100, and arranged to guide the heated semi-finished steel product P received on the first set of rollers 100 by contacting at least one ofthe opposed first and second surfaces S1 - S2. In this example, the second set of rollers 300 urge the heated semi-finished steel product P centrally on the first set of rollers 100. Axes of the second set of rollers 300 are arranged orthogonally to axes ofthe first set of rollers 100. In use, the axes ofthe second set of rollers 100 are arranged vertically. In this example, the second set of rollers 200 is arranged to guide the heated semi-finished steel product P received on the first set of rollers 100 by contacting the opposed first and second surfaces S1 - S2. In this example, each roller 300A 300D of the second set of rollers 300 is an idler roller. In this example, each roller 300A 300D ofthe second set of rollers 300 is cylindrical, having a diameter of 300 mm and a width of 400 mm.

In this example, the second set of rollers 300 comprises the first roller 300A and the opposed second roller 300C for contacting the opposed first and second surfaces S1 - S2 respectively.

In this example, the apparatus 10 is arrangeable in the first configuration, wherein the first roller 300A and the opposed second roller 300C are spaced apart; and the second configuration, wherein the first roller 300A and the opposed second roller 300C are spaced together.

The apparatus comprises a pair of pivotable guides, as described above, arranged transversely to the first set of rollers and arranged to guide the heated semi-finished steel product by contacting at least one of the opposed first and second surfaces.

In this example, the second set of rollers 300 comprises two pairs of rollers: a first pair of rollers including the first roller 300A and the roller 300E3 and an opposed second pair of rollers including the second roller 300C and the roller 300D.

The apparatus 10 comprises the first set of nozzles 400A and the opposed second set of nozzles 400E3, arranged transversely to the first set of rollers 100, and arranged to jet water therethrough towards at least a part of the opposed first and second surfaces S1 - S2 of the heated semi-finished steel product P, respectively. The first set of nozzles 400A and the opposed second set of nozzles 400E3 are arranged vertically, in use, to jet water therethrough towards at least a part of opposed lateral surfaces S1 - S2 of the heated semi-finished steel product P.

In this example, the first set of nozzles 400 A comprises 5 (i.e. a plurality of) nozzles. In this example, the plurality of nozzles of the first set of nozzles 400A are mutually equispaced and mutually coplanar. In this example, the second set of nozzles 400E3 comprises 5 (i.e. a plurality of) nozzles. In this example, the plurality of nozzles of the second set of nozzles 400B are mutually equispaced and mutually coplanar.

In this example, the first set of nozzles 400A is coupled to a first header 410A. In this example, the second set of nozzles 400B is coupled to a second header 410B. The first header 410A and the second header 410B are arranged to translate.

In this example, the first set of nozzles 400A and the second set of nozzles 400B are Series 6P3 MiniSCALEMASTER® HP Superior nozzles, specifically 6P3.767.27 nozzles.

The apparatus 10 is arrangeable in the first configuration, wherein the first set of nozzles 400A and the opposed second set of nozzles 400B are spaced apart; and the second configuration, wherein the first set of nozzles 400A and the opposed second set of nozzles 400B are spaced together.

The apparatus 10 comprises the water pump system 500 arranged to pump the water through the first set of nozzles 400A and the second set of nozzles 400B. In this example, the water pump system 500 is arranged to pump the water through a first nozzle of the first set of nozzles 400A at a rate in a range from 10 L/min to 400 L/min and/or at a pressure in a range from 100 bar to 400 bar. In this example, the water pump system 500 is arranged to pump the water through each nozzle of the first set of nozzles 400A and the second set of nozzles 400B at such rates and/or pressures.

In this example, the water has a pH of at least 7, a chloride content of at most 250 mg/kg and a chlorine content of at most 0.6 mg/kg.

The apparatus 10 comprises the controller 600 arranged to determine the cross-sectional dimension DO, specifically a width DO, of the heated semi-finished steel product P based, at least in part, on the sensed respective positions of the opposed first and second surfaces S1 S2. In this example, the sensed respective positions are distances D1 & D2 between the opposed first and second surfaces S1 - S2 and respective sensors 200A - 200B of the set of sensors 200. In this example, the controller 600 is arranged to determine the cross-sectional dimension by calculation. A third distance between the first sensor 200A and the second sensor 200B of the set of sensors 200 is measured as D12, then the cross-sectional dimension DO of the heated semi-finished steel product is be calculated by the controller to be D0 = D12-D1 -D2.

In this example, the controller 600 is a programmable logic controller (PLC). In this example, the controller 600 is arranged to receive the sensed distances D1 & D2 from the first and second sensors 200A - 200B of the set of sensors 200 a rate of 1/6 Hz.

The controller 600 is arranged to control the apparatus 10 to move from the first configuration to the second configuration based, at least in part, on the determined cross-sectional dimension DO of the heated semi-finished steel product P, whereby respective spacings D1 & D2 of the first set of nozzles 400A and the opposed second set of nozzles 400B from the opposed first and second surfaces S1 - S2 of the heated semi-finished steel product P, respectively, are controlled.

In this way, a spacing between the first set of nozzles and the opposed second set of nozzles is adjusted according to the cross-sectional dimension DO of the heated semi-finished steel product P. In this way, an efficiency of descaling of heated semi-finished steel products having different cross-sectional dimensions, for example widths, may be improved, as described previously.

In this example, the controller 600 is arranged to compare the determined cross-sectional dimension DO with a set of pre-determined cross-sectional dimensions. In this example, the controller 600 is arranged to control the apparatus 10 to move from the first configuration to the second configuration based, at least in part, on a result of the comparison.

In this example, the controller 600 is arranged to selectively control the apparatus 10 to move from the first configuration to the second configuration based, at least in part, on an error condition caused by the determined cross-sectional dimension DO of the heated semi-finished steel product.

In this example, the controller 600 is arranged to control the apparatus 10 to move from the first configuration to the second configuration wherein a first spacing s1 of the first set of nozzles 200A from the first surface S1 and a second spacing s2 of the second set of nozzles 200B from the second surface is approximately 110 mm.

In this example, the controller 600 is arranged to control a pumping speed of the pumping system 500 based, at least in part, on the determined cross-sectional dimension DO of the heated semi-finished steel product P.

In this example, the apparatus 10 comprises a third set of nozzles 400C, comprising 9 (i.e. a plurality of) nozzles, opposed to the first set of rollers 100, arranged transversely to the first and second set of nozzles 400A - 400B, and arranged to jet water therethrough towards at least a part of a third surface S3, transverse to the first and second surfaces S1 - S2 of the heated semi-finished steel product P. In this example, the water pump system 600 is arranged to pump water through the third set of nozzles 400C. In this example, the apparatus 10 is arrangeable in the first configuration, wherein the third set of nozzles 400C and the first set of rollers 100 are spaced apart; and the second configuration, wherein the third set of nozzles 400C and the first set of rollers 100 are spaced together.

In this example, the third set of nozzles 400C is arranged to translate relative to the first set of rollers 100.

In this example, the controller 600 is arranged to control the apparatus 10 to move from the first configuration to the second configuration wherein a third spacing s3 of the third set of nozzles from the third surface S3 is approximately 135 mm.

The third set of nozzles 400C is otherwise as described with respect to the first set of nozzles 400A.

In this example, the apparatus 10 comprises a fourth set of nozzles 400D, comprising 9 (i.e. a plurality of) nozzles, arranged transversely to the first and second set of nozzles 400A - 400B, and arranged to jet water therethrough towards at least a part of a fourth surface S4, transverse to the first and second surfaces S1 - S2 of the heated semi-finished steel product P. In this example, the water pump system 500 is arranged to pump water through the fourth set of nozzles 400D.

In this example, the fourth set of nozzles 400D is arranged between adjacent rollers 100B 100C of the first set of rollers 100. In this example, a position of the fourth set of nozzle 400D is fixed.

The fourth set of nozzles 400D is otherwise as described with respect to the first set of nozzles 400A. The water pump system 500 may be arranged for the fourth set of nozzles 400D similarly as described with respect to the first set of nozzles 400A.

In this example, the first set of nozzles 400A is mechanically coupled to the third set of nozzles 400C thereby defining a first plane, the second set of nozzles 400B is mechanically coupled to the fourth set of nozzles 400D thereby defining a second plane, and the first set of nozzles 400A and the second set of nozzles 400B are arranged in mutually parallel vertical planes, in use (i.e. the first plane and the second plane are mutually parallel).

In this example, the apparatus 10 includes a housing 11 arranged to shroud the sets of nozzles 400A - 400E. In this way, water and/or scale are substantially contained within the housing 11 while the nozzles 400A - 400E are protected from the mill.

In use, the heated semi-finished steel product P is received firstly on the roller 100A. The sensors 200A - 200B sense respective distances D1 & D2 of the opposed first and second surfaces S1 - S2 therefrom, which are sent to the controller 600. The controller 600 determines the width DO of the heated semi-finished steel product P, compares the determined cross-sectional dimension DO with the set of pre-determined cross-sectional dimensions and controls the apparatus 10 to move from the first configuration to the second configuration based, at least in part, on the determined cross-sectional dimension DO of the heated semifinished steel product P. The controller 600 controls the first set of nozzles 400A and the second set of nozzles 400B to translate such that the first spacing s1 of the first set of nozzles 400A from the first surface S1 and the second spacing s2 of the second set of nozzles 400B from the second surface S2 to be approximately 110 mm. The controller 600 controls the third set of nozzles 400C to translate such that the third spacing s3 of the third set of nozzles 400C from the third surface S3 to be approximately 135 mm. The controller 600 controls the first roller 300A and the opposed second roller 300C to move together such that the first roller 300A and the opposed second roller 300C contact at least one of the opposed first and second surfaces S1 - S2. The heated semi-finished steel product P moves on the roller 100A and is urged centrally thereon by the second set of rollers 300. The heated semi-finished steel product P is received subsequently also on the roller 100B and continues to move forwards towards the sets of nozzle 400, whereupon the heated semi-finished steel product P is progressively descaled along its length as the heated semi-finished steel product P moves through the jetting water. The descaled portion of the heated semi-finished steel product P is received on the rollers 100C - 100E in turn.

Figures 2A and 2B schematically depict cross-sections through the descaling apparatus 10 of Figure 1, in use.

Particularly, Figure 2A schematically depicts a cross-section through the apparatus 10 arranged in the first configuration and Figure 2B schematically depicts a cross-section through the apparatus 10 arranged in the second configuration.

In Figure 2A, a heated first semi-finished steel product P1, having a relatively larger width D01 (i.e. cross-sectional dimension), is received on the first set of rollers 100. The controller 600 controls the first set of nozzles 400A and the second set of nozzles 400B to translate, based, at least in part, on the determined relatively larger width D01, such that the first set of nozzles 400A is at a first spacing s1 from a first surface S1 of the heated first semi-finished steel product P1 and that the second set of nozzles 400B is at a second spacing s2 from a second surface S2 of the heated first semi-finished steel product P1. The controller 600 controls the third set of nozzles 400C to translate such that third set of nozzles 400C is at a third spacing s3 from the third surface S3 of the heated first semi-finished steel product P1.

In Figure 2B, a heated second semi-finished steel product P2, having a relatively smaller width D02 (i.e. cross-sectional dimension), where D02 is less than D01, is received on the first set of rollers 100. The controller 600 controls the first set of nozzles 400A and the second set of nozzles 400B to translate, based, at least in part, on the determined relatively smaller width D02, such that the first set of nozzles 400A is at the same first spacing s1 from a first surface S1 of the heated second semi-finished steel product P2 and that the second set of nozzles 400B is at the same second spacing s2 from a second surface S2 of the heated second semifinished steel product P2. The controller 600 controls the third set of nozzles 400C to translate such that third set of nozzles 400C is at the same third spacing s3 from the third surface S3 of the heated second semi-finished steel product P2.

Figure 3 schematically depicts a first part of a steel mill 1 including a first descaling apparatus 10A, such as that described with respect to Figure 1. The first part of the steel mill 1 includes a first furnace 2A (also known as a bloom furnace) arranged to heat blooms (i.e. first semifinished steel products) therein. The first part of the steel mill 1 includes an extractor 3 arranged to extract heated blooms from the first furnace 2 onto a first roller table 4A. The first roller table 4A is arranged to move a heated bloom thereon to the apparatus 10A for descaling. A second roller table 4B is arranged to receive a descaled heated bloom from the descaling apparatus 10 and move the descaled heated bloom to a cogging mill stand 5 (not shown), arranged to cog the descaled heated bloom before shearing the descaled heated bloom into bars (i.e. second semi-finished steel products) in a shearing mill stand 6 (not shown).

Figure 4 schematically depicts a second part of the steel mill 1 including a second descaling apparatus 10B, such as that described with respect to Figure 1. The second part of the mill 1 includes a second furnace 2B (also known as an interfurnace) arranged to heat the bars formed by shearing the cogged, descaled heated bloom. A peel bar 7 is arranged to move a reheated bar from the second furnace 2B to the second descaling apparatus 10B for descaling before hot rolling to form a hot rolled steel profile therefrom in rolls 8 (not shown).

Figure 5 schematically depicts a method of processing steel according to an exemplary embodiment. Particularly, the method comprises descaling a heated first semi-finished steel product by jetting water through at least a first set of nozzles towards at least a part of a first scale on a first surface thereof.

At S501, a first cross-sectional dimension of the heated first semi-finished steel product is determined.

At S502, a first spacing of the first set of nozzles from the first surface is controlled based, at least in part, on the determined first cross-sectional dimension of the heated first semi-finished steel product.

At S503, the heated first semi-finished steel product is descaled by jetting water through the first set of nozzles spaced apart from the first surface according to the controlled first spacing.

The method may include any of the steps described herein.

Figure 6 schematically depicts a method of processing steel according to an exemplary embodiment.

At S601, a first semi-finished steel product is received.

At S602, the first semi-finished steel product is heated in air to a temperature of at least 1150 °C, whereby a first scale is formed on at least a first surface thereof.

At S603, the heated first semi-finished steel product is descaled by jetting water through at least a first set of nozzles towards at least a part of the first scale on the first surface thereof, wherein descaling the heated first semi-finished steel product comprises steps S604 to S606, as described below.

At S604, a first cross-sectional dimension of the heated first semi-finished steel product is determined.

At S605, a first spacing of the first set of nozzles from the first surface is controlled based, at least in part, on the determined first cross-sectional dimension of the heated first semi-finished steel product.

At S606, the heated first semi-finished steel product is descaled by jetting water through the first set of nozzles spaced apart from the first surface according to the controlled first spacing.

At S607, a plurality of heated second semi-finished steel products is optionally provided by rolling the descaled, heated first semi-finished steel product and dividing the rolled, descaled, heated first semi-finished steel product into the plurality of heated second semi-finished steel products.

The method may include any of the steps described herein.

Figure 7 schematically depicts a method of processing steel according to an exemplary embodiment.

At S701, a first semi-finished steel product is received.

At S702, the first semi-finished steel product is heated in air to a temperature of at least 1150 °C, whereby a first scale is formed on at least a first surface thereof.

At S703, the heated first semi-finished steel product is descaled by jetting water through at least a first set of nozzles towards at least a part of the first scale on the first surface thereof, wherein descaling the heated first semi-finished steel product comprises steps S704 to S705, as described below.

At S704, a first cross-sectional dimension of the heated first semi-finished steel product is determined.

At S705, a first spacing of the first set of nozzles from the first surface is controlled based, at least in part, on the determined first cross-sectional dimension of the heated first semi-finished steel product.

At S706, the heated first semi-finished steel product is descaled by jetting water through the first set of nozzles spaced apart from the first surface according to the controlled first spacing.

At S707, a plurality of heated second semi-finished steel products is provided by rolling the descaled, heated first semi-finished steel product and dividing the rolled, descaled, heated first semi-finished steel product into the plurality of heated second semi-finished steel products.

At S708, a heated second semi-finished steel product of the plurality of second semi-finished steel products is reheated in air to a temperature of at least 1150 °C, whereby a second scale is formed on at least a second surface thereof.

At S709, the reheated second semi-finished steel product is descaled by jetting water through at least the first set of nozzles towards at least a part of the second scale on the second surface thereof, wherein descaling the reheated second semi-finished steel product comprises steps S710 to S712, as described below.

At S710, a second cross-sectional dimension of the reheated second semi-finished steel product is determined.

At S711, a second spacing of the first set of nozzles from the second surface is controlled based, at least in part, on the determined second cross-sectional dimension of the reheated second semi-finished steel product.

At S712, the reheated second semi-finished steel product is descaled by jetting water through the first set of nozzles spaced apart from the second surface according to the controlled second spacing.

At S713, a hot rolled steel profile is provided by rolling the descaled, reheated second semifinished steel product.

The method may include any of the steps described herein.

Figures 8A and 8B schematically depict semi-finished steel products, P1 and P2 respectively, having scale SC on surfaces thereof.

Figures 9A to 9C are photographs of heated semi-finished steel products having scale on surfaces thereof and Figure 9D is a photograph of a heated semi-finished steel product according to an exemplary embodiment.

Particularly, Figures 9A to 9C shows hot (approximately 1250 °C) blooms B1 to B3 respectively, having relatively large areas of scale SC on surfaces thereof, contrary to the acceptance criteria described herein.

In contrast, Figure 9D shows a hot (approximately 1250 °C) blooms B4, having no visible scale S on surfaces thereof, in compliance with the acceptance criteria described herein.

Figure 10 schematically depicts a surface quality index of a hot rolled steel profile.

As described previously, with reference to Table 1, the surface quality index may be defined according to a proportion, a distribution and a size of surface defects (also known as discontinuities) of the hot rolled steel profile, as shown schematically in Figure 10.

Figures 11A to 11C are photographs of hot rolled steel profiles having surface defects in surfaces thereof and Figure 12 is a photograph of a hot rolled steel profile according to an exemplary embodiment.

Particularly, Figures 11A to 11C show fork flats F1 to F3, respectively, having surface quality indices of at most 2, due to rolled in scale S and impressions I due to scale.

In contrast, Figure 12 shows a fork flat F4 having a surface quality index of at least 8.

Figure 13A is a photograph of a hot rolled steel profile having surface defects in a surface thereof and Figure 13B is a photograph of a hot rolled steel profile according to an exemplary embodiment.

Particularly, Figure 13A shows a fork flat F5 having a surface quality index of at most 4, due to rolled in scale S and impressions I due to scale.

In contrast, Figure 13B shows a fork flat F6 having a surface quality index of at least 8.

Figure 14 schematically depicts a cross-section of a bulb flat according to an exemplary embodiment.

The cross-section is asymmetric, being generally rectangular and having a bulb at one side. A width b is in a range from 160 mm to 430 mm and a thickness t is in a range from 7 mm to 20 mm. Bulb flats may have lengths in a range from 6 m to 18 m.

Figure 15 schematically depicts a cross-section of a crane rail according to an exemplary embodiment. Other sizes may be provided.

Figures 16A to 16C schematically depict cross-sections of track shoe profiles according to exemplary embodiments.

Particularly, Figures 16A to 16C show cross-sections of single, double and triple grouser track shoe profiles, typically having widths W in a range from 173 mm to 369 mm. The crosssections are asymmetric, having one, two and three protrusions upstanding from generally rectangular cross-sections, respectively. Opposed sides are arranged to mate with adjacent similar track shoes, having a male convex part and a female concave part, respectively.

Grouser heights H may typically be in a range from 19 to 102mm. Track shoe thickness T may typically be in a range from 7.9 to 30 mm.

Figures 17A to 17D schematically depict cross-sections of cutting edge profiles according to exemplary embodiments.

Particularly, Figures 17A to 17D show cross-sections of a single bevel flat, a double bevel flat, a grader bars and an arrowhead flat, respectively.

W may typically be from 152 to 480 mm, T typically from 12.7 to 60 mm, A typically from 22.5 to 25° and B typically from 23.6 to 98.7 mm.

Figure 18 schematically depicts a cross-section of a top hat profile according to an exemplary embodiment. Various sizes may be provided.

Although a preferred embodiment has been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims and as described above.

In summary, the invention provides a descaling apparatus for descaling heated semi-finished steel products by water jetting has a first set of rollers to receive a heated semi-finished steel product, a set of sensors for sensing opposed first and second surfaces the product, a second set of rollers arranged to guide the product, a first set of nozzles and an opposed second set of nozzles arranged to jet water towards the opposed first and second surfaces and a water pump system arranged to pump water through the nozzles. The apparatus has a controller arranged to determine a cross-sectional dimension of the product based on the sensed positions of surfaces. The first set of nozzles and the opposed second set of nozzles are spaced apart or together. The controller is arranged to control the apparatus move the nozzles apart or together based on the determined cross-sectional dimension of the product whereby respective spacings between the nozzles are controlled. Also provided are methods using the apparatus and semi-finished and hot rolled steel profile made using the apparatus. Hence, the invention provides a descaling apparatus, a method of processing steel, a semi-finished steel product and a hot rolled steel profile. By determining a size of a heated semi-finished steel product, positions of descaling water jet nozzles may be controlled, thereby improving an efficiency of descaling, particularly for different heated semi-finished steel products having different sizes. In this way, a surface quality of the hot rolled steel profile may be improved, having fewer and/or smaller surface defects due, at least in part, to residual scale.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at most some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A hot rolled steel profile having a surface quality index of at least 6, preferably at least 7, more preferably at least 8, wherein the surface quality index is defined according to a proportion, a distribution and a size of surface defects ofthe hot rolled steel profile.

2. The hot rolled steel profile according to claim 1, wherein an area ofthe surface defects as a percentage of total surface area ofthe hot rolled steel profile is at most 5 %, preferably at most 3.5 %, more preferably at most 2 %.

3. The hot rolled steel profile according to any previous claim, wherein the distribution of surface defects is uniform.

4. The hot rolled steel profile according to any previous claim, wherein a distribution of depth of the surface defects is at most 0.3 mm.

5. The hot rolled steel profile according to any previous claim, having no surface defects including ‘snake skin effect’, ‘tiger scale’, ‘salt and pepper’, ‘drag or comet’ and/or banding defects.

6. The hot rolled steel profile according to any previous claim, wherein the hot rolled steel profile is as hot rolled or as-received.

7. The hot rolled steel profile according to any previous claim, wherein the hot rolled steel profile has a unit mass of at least 20 kg/m, at least 30 kg/m, or at least 40 kg/m.

8. The hot rolled steel profile according to any previous claim, wherein the hot rolled steel profile has a unit mass of at most 400 kg/m, at most 300 kg/m, or at most 270 kg/m, for example 260 kg/m.

9. The hot rolled steel profile according to any previous claim, wherein the hot rolled steel profile is formed by a rolling reduction ratio in a range from 2:1 to 50:1, preferably in a range from 3:1 to 27:1.

10. The hot rolled steel profile according to any previous claim, wherein the hot rolled steel profile has a symmetrical cross-section, having at least one line of symmetry.

11. The hot rolled steel profile according to any of claims 1 to 9, wherein the hot rolled steel profile has an asymmetrical cross-section, having no lines of symmetry.

12. The hot rolled steel profile according to any previous claim, wherein the hot rolled steel profile is a bulb flat profile, a crane rail profile, a forklift profile, a track shoe profile, a cathode collector bar profile, a cutting edge profile, a top hat profile, a conveyor channel section or a bull wheel profile.

13. The hot rolled steel profile according to claim 12, wherein the hot rolled steel profile is a bulb flat profile, having a width in a range from 100 mm to 430 mm, a thicknesses in a range from 7 mm to 20 mm and a length in a range from 6 m to 18 m.

14. The hot rolled steel profile according to claim 12, wherein the hot rolled steel profile is a crane rail profile according to DIN 536-1, for example 690, 880 and 90V.

15. The hot rolled steel profile according to claim 12, wherein the hot rolled steel profile is a forklift profile, for example a mast profile (including U, I, J and offset J profiles), a carriage (also known as hanger) bar profile or a flat for manufacturing fork arms.

16. The hot rolled steel profile according to claim 12, wherein the hot rolled steel profile is a track shoe profile of a single, double or triple grouser (spike) design, having a width in a range from 170 mm to over 350 mm.

17. The hot rolled steel profile according to claim 12, wherein the hot rolled steel profile is a cathode collector bar profile having a section width in a range from 122 mm to 279 mm and a thickness in a range from 90 mm to 160 mm.

18. The hot rolled steel profile according to claim 12, wherein the hot rolled steel profile is a cutting edge profile, for example a single bevel flat, a double bevel flat, a grader bar or an arrowhead flat.

19. The hot rolled steel profile according to claim 12, wherein the hot rolled steel profile is a top hat profile or a conveyor channel section according to EN 10025-2: 2004 grade S275J0+AR, S355JR+AR or S355J2+AR, SANS grade 50025-2: 2009 S275J0+AR, S355JR+AR or S355J2+AR, CSA grade G40.21-04: 2004, 300W, 350W or 350WT or AS/NZS 3679.1 grade 350.

20. The hot rolled steel profile according to claim 12, wherein the hot rolled steel profile is a bull wheel profile for a bull wheel to drive a cable.