KR930002544B1 - Matrix coating flexible casting belts, method and apparatus for making matrix coatings - Google Patents

Abstract

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Description

Matrix coatings Flexible casting belts and methods and apparatus for forming matrix coatings

1 is a side view showing one of a casting zone, a casting belt and a pulley and a casting side dam of a twin belt continuous casting machine;

2 is an enlarged cross-sectional view of the casting space and its periphery taken along line 2-2 of FIG.

3 is a perspective view of a single belt covering machine viewed from an idling end.

4 is an enlarged perspective view of the steering mechanism of the single belt coater of FIG. 3 taken along line 4-4 of FIG.

5 is a perspective view of a modification of the coating machine of FIG.

FIG. 6 is an enlarged perspective view of the preferred lateral "floating" thermal spray gun assembly seen from the working end of the belt covering machine, showing an improved version of the belt covering machine shown in FIGS.

The present invention first relates to a flexible belt for use in a continuous casting machine for casting ferrous or nonferrous metals. More specifically, the present invention is directed to protective and thermally insulated matrix coatings, coating formation methods, coating compositions, and coated belts so produced. Casting belts are usually made of mild steel. Secondly, the present invention also applies to the coating of other molten metal contact surfaces in continuous casting machines, such as the coating of side dam blocks.

Various mixtures of oils, graphite, soot, diatoms, silica, organic binders, etc. protect the metal casting belts or insulate the metal casting belts and / or prevent them from adhering to the belt of continuous casting machines for molten metal castings. It acted as a separating agent. These conventional sheaths were inherently temporary or temporary and had to be continuously provided or supplemented during the casting process. Providing such coatings during the casting process needs to be accurately maintained and controlled in the sense that continued thermal conductivity is required.

Continuous coating and replacement of temporary insulating coatings is a difficult and inaccurate technique. For example, if excess solution or solvent binder is in the insulating coating material, it generates enough gas to destroy the firmness of the casting and eventually create pores. The gas so liberated is often hydrogen and this can adversely alter the metallurgical properties of the cast metal. In addition, an excessive amount of temporary insulating coating material itself may accumulate near the edges of the casting and intrude some of the continuously moving mold space, causing defects in the casting.

Two-layer belt coatings used for continuous casting of relatively low melting metals such as aluminum, zinc and lead and containing thermosetting resins and solvents are disclosed in US Pat. No. 3,871,905. Resin-containing coatings are generally not suitable for continuous casting of metals with much higher melting points than aluminum.

Casting belts made of soft-kilted steel containing 0.2 to 0.8 weight percent titanium are multi-layered as described in US Pat. No. 4,298,053. The belt surface is first covered with a "primer" layer of nickel-aluminum alloy (80% by weight Ni and 20% by weight Al), which is described as 0.005 mm thick but claims only 0.05 mm thick. It became.

The primer layer is coated with chromium, chromium alloys, nickel, nickel alloys, or other layers of 0.01 to 0.5 mm in thickness made of stainless steel.

Next, a third layer, which is a closed graphite anti-adhension agent, is provided again on the second layer.

However, experience of the present cause requires greater thermal insulation and additional non-wetting than can be obtained according to the above patents as described below.

Shim and Gonzago's Canadian Patent No. 1,062,877 is an endless casting of multiple layers (80-100 μm, preferably 50-70 μm) on an endless cast belt until the ceramic layer has the desired thickness to provide the necessary heat resistance. The coating of the belt is described.

Forming multiple ceramic layers is laborious, time consuming and expensive.

The built-up coating thus obtained is subjected to machining, such as grinding, for the wetting behavior and uniform surface finish between the multilayer ceramic coating and the cast aluminum. The laminated ceramic coating is composed of A1 ₂ O ₃ .CaZrO ₃ , A1 ₂ O ₃ .MgO, ZrSiO ₄ or A1 ₂ O ₃ .TiO ₂ .

The thickness is applied until it provides heat resistance in the range of 10 ⁻⁴ to 10 ⁻³ m ² · h · C / kca 1. Laminated coatings are usually relatively thick and fragile. Lack of durability to withstand thermal shock, mechanical elongation and relaxation, and flexibility and wear, a common feature of continuous casting machines employing one or more moving belts as molten metal contact cooling surfaces.

Durability to withstand such mechanical and thermal stresses is important, without which the pieces of ceramic coating are peeled off during the work required for continuous casting of molten metal.

Falling pieces are inevitable to get into cast metal products.

Such incorporation can be a serious problem, for example in the case of copper to be drawn into fine wires. This mixing leads to a decrease in productivity, such as breaking the wire at the die and requiring the wire to be reconnected.

Ceramic coatings are usually inflexible and tend to break.

The problems associated with chipping, delamination and contamination of castings with ceramic particles are highlighted in Deobald's German Patent No. 2411448, which provides a second protective wear resistant metal layer with a higher melting point than the metal to be cast during aluminum casting. Attempts to solve this problem by providing on relatively thick ceramics are described in this patent.

Partially metallic, single layer on endless flexible metal casting belts for continuous casting machines, the deposition matrix coating having adequate adhesion, mechanical and thermal durability and non-wetting.

The deposition matrix coating is also useful for covering other molten metal contact surfaces of the continuous casting machine, for example, side dam blocks that define the moving side walls of the mold cavity.

The deposition matrix (or reticulated) coating provides a useful accessible porosity throughout the coating and is a nonmetal refractory material that is substantially uniformly interspersed in a matrix of heat-resistant metals or metal alloys, such as nickel or nickel alloys. These metals or metal alloys are deposited on the grit-blasted surface of the belt to adhere and support the nonmetallic material.

The coating is achieved by thermally thermal spraying the powder mixture directly onto the rough surface.

The resulting coating insulates and protects the belt from direct contact of molten metal, thermal stress and resulting torsional shear deformation, and stress corrosion behavior or chemical corrosion by molten metal or its oxides or slags.

The nonmetallic material is at least partly in the form of an isolated particle surrounded by a metal network and / or a second network structure intertwined with the metal network. The life of the coated belt is significantly increased, and the surface material and properties of the cast are significantly improved.

The coating more uniformly controls the rate of solidification of the metal being cast, resulting in improved metallurgical properties.

The construction and formation method of the coating by thermal spraying will be described.

1 and 2 illustrate the casting zones and adjacent components of a twin belt casting machine comprising a lower casting belt 10 which rotates around the pulleys 12 and 14, and the pulleys 12 and 14 are provided with a lower carriage ( It is a member combined with L).

The pulley 12 is located at the inlet or upstream end of the casting machine and the pulley 14 is at the outlet or downstream end of the casting machine.

The continuous moving casting mold C is defined between the lower casting belt 10 and the upper casting belt 20 in combination with a pair of spaced side dams 16 and 18 (FIG. 2), and the upper and lower casting belts are Move together along the casting zone (C).

Lateral dams are guided by rollers 22. The lateral dams are composed of a plurality of dam blocks 24 each of which are grooves in which the straps 25 are fitted.

The seal 26 prevents water from penetrating between the belts and prevents water from seeping into the casting zone C.

The fixed guide 27 guides the moving side dam. The upper casting belt 20 rotates around the pulleys 28 and 30 and is a member of the upper carriage U.

A finned backup roller 32 defines the position of the belt in the casting zone C and allows the coolant to flow quickly along the back of each belt. Molten metal is fed into the casting machine at the upstream end as indicated by arrow 31 in FIG. The casting P is discharged from the lower end.

In the present invention, each of the belts 10 and 20 is covered before being installed on the respective belt carriers L and U.

As can be seen from Figures 1 and 2, the molten metal contact surface of each belt is the outer surface and sometimes called the front surface, while the inner surface is called the rear surface. The flexible cast belts 10 and 20 are typically made of low carbon steel rolled to moderate hardening and have a thickness of 0.035 to 0.065 inches, although thinner or thicker ones may be used. Occasionally, at the request of the consumer, a belt may be made of steel containing work hardened titanium that is sufficiently rolled to maximum hardening, as described in Tompars, US Pat. No. 4,092,155.

In order to coat the belt 10 or 20, the oil remaining on the outer surface of the belt must first be washed with an alkaline cleaner and then wiped off with a clean solvent.

The outer surface of the belt is then grit-blasted to roughen it.

Grit-blasting, for example, is performed with 20-grit aluminum oxide at an air pressure of 40-100 psi (300-700 kpa).

20-grit size refers to aluminum oxide particles that pass through a screen with 20 lines of wire per inch.

Air pressures belonging to the lower range of the above air pressure ranges are used when grit blasting thinner belts belonging to the thinner part of the aforementioned belt thickness range, because otherwise the impact of the grit roughens the back of the belt.

Air pressures in the lower range of the range are also recommended when the belt is not flattened by a roller stretcher.

Typically, the belt is flattened by roller extension after grit-blasting to control the torsional shear deformation within the tolerances as described below.

The blasted surface roughness is preferably in the range between 0.002 inches and 0.003 inches (2000-3000 μinch or 52-76 μm), which is an easily obtained range, although the useful range of roughness can sometimes extend from about 0.001 inch to 0.005 inch.

The surface roughness as described above is determined by the value measured by the surface polishing method by a preferred method. In this preferred method, the thickness of the blasted belt specimen is usually measured using a micrometer caliper.

Place the specimen on the magnetic chuck of the surface polisher and carefully polish the surface until the polished surface is smooth.

The belt specimen is again measured with a micrometer caliper to regard the difference in measurements as roughness.

In comparison, the maximum roughness of the grit blasted surface obtained by vertical measurement with a microscope of × 400 is, in our experience, 150% conduction of measurements obtained by surface polishing and micrometer methods.

Grit-blasting processes usually require roller elongation by torsional shear deformation of the belt.

Leveling is for example seed. W. Bending and ironing is performed by passing the back of the belt through a multi-tight roller, as described in Hegelet, US Patent No. 2,904,860.

Next, a thermal spray is used to provide a welding matrix protection and insulation coating, which is a single-sided coating, directly on the grit-blasted rough belt surface.

Spacing: At least 5 inches (127 mm), traverse speed: 30 to 50 feet per minute (9 to 15 meters) is a good way to thermally spray the coating material by combustion flame (oxygen acetylene flame).

If the material to be sprayed is not overburned in the flame, oxygen acetylene spray coating is successful.

Large nonmetallic particles will not melt completely.

Moreover, the oxygen acetylene salt is not sufficient to keep the nonmetal particles in a molten state for a time necessary for depositing the nonmetal particles on other particles of the same kind as those deposited on the belt surface.

If there are more metal particles mixed with the nonmetal, this is not a good condition for mixing the nonmetal components. Thus, in such a case, at least in part the nonmetallic material will be in the form of isolated particles surrounded by or contained within the metal mesh.

Plasma spraying is another thermal spraying method that uses electricity.

Combustion (oxyacetylene) sprays are often called flame spraying. This nomenclature is often confused with the use of plasma flames by the use of plasma flames. Both types of warriors use fire.

The term "thermal spray" is a term herein that includes oxygen acetylene flame sprays and electrically energized plasma sprays.

Plasma sprays usually operate at higher temperatures than oxygen acetylene sprays, resulting in less porosity.

The higher high temperatures provided by electrically energized (plasma) sprays can more quickly melt metals and nonmetallic materials provided in coarse form, such as sticks, rods or wires (unlike phases) and thus I think coarse metals and nonmetallic materials can be adopted.

However, whether or not this is actually true, as described below, a mixture of suitable metal and nonmetallic components can be used to successfully provide a deposition matrix coating having an appropriate rate of accessible pores.

When using most conventional thermal sprays, pores were avoided as much as possible. In the present invention, the applicant has found that the fact is the opposite.

It is desirable and important to control the porosity characteristics in the deposition matrix coating. Porosity controlled to an appropriate level substantially contributes to the insulation of the matrix coating.

On the other hand, an appropriate level of porosity also improves non-wetting properties for molten metals, which is a desirable property. We believe that this improvement in non-wetting is largely due to air in the pores of the porous coating.

When molten metal is introduced adjacent to the covering belt, the air in the pores is heated out of the pores to form a gas film between the molten metal and the belt coating to form a solidified metal film on the product cast in the continuous casting process. Prevents wetting of the cover belt by molten metal during the period.

It is important to note that the controlled porosity in the matrix coating has the advantage of acting as an absorber or disperser for moisture on the surface of the casting belt, which is generated by the condensation or the flow of coolant droplets.

This absorption or dispersion of moisture prevents bubbles, rosettes or needles from appearing on the surface of the cast product P adjacent to the liquid contamination.

This aspect of dispersing or absorbing moisture, for example, is important in the casting of aluminum sheet P having a high quality suitable for anodization as opposed to a low surface quality suitable for painting.

Moreover, there are two more reasons why controlled porosity is important.

One is that it improves thermal shock resistance.

The other is to increase the resistance to delamination under rough machining. All of these properties are important for coatings which are composed mainly of ceramic material, i.e. weak material.

Under thermal shock, because there are already a myriad of potentials as pores, the pores allow internal adjustments without generating relatively many potentials, each of which has a myriad of needs for internal adjustments to accommodate thermal shock and mechanical flexibility and elongation. I think it contributes a little.

Therefore, the controlled porosity does not reduce the effective strength of the matrix coating but actually increases the strength.

It seems that the desired porosity is extended over the entirety of the deposition matrix, which is a single layer.

The fact that this porosity extends throughout the matrix coating is evidenced by the fact that the coating is rusted if moisture remains.

In summary, the significant but controlled porosity in the deposition matrix coating, which is monolayer on the belt of a continuous casting machine, has four advantages that are important for the present invention. There is an upper limit of ubiquitous porosity.

The upper limit in a given configuration is reached when the integrity of the coating is broken. In the case where the metal component prevails (determined by weight) in the matrix coating, the upper limit is when the accessible porosity is at least 35% by volume.

For coatings where the nonmetallic component is predominant (judged by weight), the upper limit is where the accessible porosity is about 12-20% by volume.

There is a lower limit of the desired accessible porosity by volume in the matrix. The reason is that the lack of porosity may not have the four advantages described above. The lower limit is about 4-8%.

As described below, the accessible void space, that is, the effective porosity, was tested and measured as a ratio with respect to the volume of the matrix coating. These tests and measurements were performed to better understand the variables contributing to the desired porosity.

The thermal sprayed material is about 0.050 inch (1.3 mm) thick on specimens of about 14 square inches of mild steel belts. The specimen was dried and weighed. Then briefly immersed in water to which Kodak Photo-Flo was added; Then I took it out and wiped out any water that wasn't absorbed. The specimens were weighed again to divide the weight increase by the coating volume in cm ³ to obtain the proportion of accessible voids in water and the weight gain was absorbed into the coating. There are pores in a given specimen that are closed or not measured by water absorption.

However, an accessible cavity that is heated to release gas and absorbs water is more important for the favorable behavior of the matrix coating during the casting process. Thus, a method for measuring effective pores, which only counts fluid-exclusive or especially water-exceptible pores, is particularly suitable for the purposes herein.

Table A below shows the water-excessible pores obtained by measuring several specimens thermally thermally sprayed with the dispersion mixture of the configurations reported in the table under the conditions described as a percentage of the total volume of the matrix coating.

TABLE A

[Composition]

Preferred single layer deposition protection matrix coatings are of the same composition throughout their thickness.

This matrix coating is composed of a non-metallic refractory that is substantially uniformly dispersed throughout the matrix of heat-resistant metal components or components. This metal component is a metal or metal alloy and must exhibit five critical properties:

1) Metal components shall have heat resistance and resistance to heat cycles. In other words, the metal component must have a sufficiently high melting point relative to the temperature of the molten metal that is cast to withstand excessive degradation during the life of the belt in continuous casting and is due to excessive and repeated heat cycles that occur during continuous casting. It must be able to withstand excessive degradation.

The melting point of the metal component need not be higher than the temperature at which the molten metal enters the continuous casting machine, but at least near that temperature.

2) Metallic components shall be heat weldable with flexible cast steel belts to which the matrix coating is welded.

3) Metallic components shall have at least some ductility to withstand the rough machining experienced by matrix-coated belts during continuous casting. The twin belts are repeatedly bent and stretched around the pulley rolls. In addition, the twin belts are subjected to high stresses during use.

4) Metallic components shall have a coefficient of thermal expansion not different from that of non-metallic components contained in the matrix coating in order to withstand repeated extreme thermal cycles occurring during continuous casting without delamination into pieces.

5) Metallic components should have sufficient oxidation resistance under thermal spraying conditions and under continuous casting conditions to avoid excessive oxidation.

We have found that nickel and nickel alloys are particularly suitable for forming the metal components of the matrix coating of the present invention.

Cobalt, iron and titanium have also been shown to have the five critical properties described above which are useful as metals or alloys for forming the metal components of the matrix coating. Those skilled in the art will find that other metals or alloys may be used as appropriate.

The matrix coating of the present invention is made by thermal spraying of mixed metal and nonmetallic components according to the configuration within the following ranges:

Metal component: about 38 to about 90 weight percent

Non-metallic component: about 62 to about 10 weight percent

The cause is that the volume of metal components present in the matrix coating to form an integral, molten mesh, network or matrix of metal components to secure or retain the non-metallic components on the belt must be sufficiently large relative to the non-metallic components. I concluded that When the nonmetallic component is also in the upper region of the range, it will form intertwined network throughout the metal network.

The nonmetallic component, when in the lower region of the range, will be at least partially in the form of an isolated particle enclosed in or encased in the mesh. Therefore, the metal component forms a fixation / holding matrix or a network, and the non-metallic component is uniformly distributed throughout the network as a second network or as separate particles.

The metal component typically has a specific gravity of about 1.5 to about 4 times the specific weight of the nonmetal component. Therefore, when two components are present in the coating at 50% by weight, the volume ratio of the nonmetallic particles to the metal particles is about 2.5. On the other hand, when the metal component constitutes 85% by weight of the coating composition, the volume ratio of the nonmetal to the metal is about 1 / 2.5.

Recent preferred compositions use nickel and graphite powder mixtures, which are at least partly metallic and nonmetallic components, with nickel crystals surrounding the graphite powder and graphite consisting of 15 to 25% of the mixed weight. Nickel and graphite mixtures are commercially available, for example, from Bay State Ables, West Borough, Massachusetts.

Preliminary tests for pouring molten steel (1010) molten metal at about 1530 ° C (2786 ^o F) on a steel casting belt specimen with a coating of the coating matrix according to the present invention were obtained commercially containing 8% aluminum and about 5% molybdenum. Possible nickel alloys have been shown to be suitable metal alloys for use with powdered zirconia or graphite as a suitable nonmetallic component to form a durable matrix coating.

Other metal, alloy or nonmetal refractories such as silica or alumina are suitable as components of the deposition liquid porous matrix coating provided by the present invention.

The critical properties required for metals and alloys have been described in more detail and clearly above. Metallic components have adequate heat resistance and resistance to heat cycles, low carbon steel belt bonds, some ductility, and thermal expansion coefficients that are not significantly different (compatibility) with the non-metallic components they contain. If thermal spraying is used, it also has oxidation resistance.

Current preferred insulating materials for use as at least part of the nonmetallic component are zirconium oxide, ie, ZrO ₂ , zirconia, in the form of fractions of 0.0005 to 0.0014 inches (12 to 36 μm) in size.

Zirconia-based nonmetallic components have the advantage of having an expansion coefficient closer to that of steel and nickel than other useful metal oxides having a low coefficient of expansion.

Yttria (yttrium oxide, Y ₂ O ₃ ) added in various amounts up to about 20% stabilizes the structure of the zirconia crystals exposed to high temperatures, thereby preventing premature relaxation of crystal grains due to minor changes in mechanical properties during the thermal cycle. prevent.

Other metal oxides, such as magnesia (MgO) and lime (CaO), can also be used for this thermal stabilization purpose.

Lime (CaO) is economical and in our experience yielded desirable results. Economical lime (calcium oxide) is therefore currently preferred as a heat stabilized compound. Lime is a component of commercial zirconia and contains from 4 to 5% by weight of zirconia.

The nonmetallic particles or powder are thoroughly mixed with the powdered metal and the mixture is thermally sprayed directly on the grit-blasted surface of the belt. Separation of the powder mixture during the thermal spraying process should be avoided.

As described above, zirconia alone or other non-metallic materials alone may lose adhesion under adverse circumstances and release the nonmetallic fragments into the coagulated metal product. This peeling problem should be minimized or avoided in the matrix coating of the present invention by paying attention to the following requirements.

The zirconia powder should preferably be fine enough to pass through the screen with fine particles of 300 or more wires per inch as fine particles.

The metal components in the powder phase mixture are sufficient to form an integral molten network or network in the belt capable of firmly securing the zirconia particles in a relatively discontinuous arrangement and / or a second network intertwined with the metal network as described above. There should be a lot.

Furthermore, the finished single layer deposition matrix coating should be brushed, dedusted or vacuumed before use.

Graphite is a high heat resistant separator that sublimes without melting at 3700 ° C. This is a useful nonmetallic component because it is not wetted for almost all molten metals. Moreover, if the graphite particles are in the metal product, most of the problems caused by the accidental incorporation of foreign substances can be prevented by the flexibility, brittleness, lubricity and inertness of the product.

Under the pressure of rolling or drawing, graphite particles break or break into finer particles.

According to the experience of the present application, in the case where the appropriate powdered metal phase and the powdered nonmetallic material are completely mixed, the mixture thus obtained (particularly containing very fine powder) may not flow freely and uniformly through the path of the thermal spray gun. The result is a non-uniform coating.

In many cases, the flow of the powder mixture in the powder mixture is substantially improved with at least 0.25% by weight of spherical fumed silica (SiO ₂ ) in order to freely flow the mixed powder and the thermal spray coating becomes uniform. . The amount of this fumed silica lubricant is not critical and good results have been obtained for most powder mixtures.

Fourteen silica particles on the order of 0.014 μm (14 milli microns) allow the powder mixture to flow freely successfully. The 0.014μm size is less than a millionth of an inch and is nominal.

Examples of suitable configurations for forming the matrix coating of the present invention are described below.

Example I

Example II

Example III

Example IV

Example V-III

Similar configurations for forming the matrix coating of the present invention can be obtained by partially or completely replacing cobalt with respect to the corresponding weight percentages of nickel in the four embodiments described above.

Example IX

In Example IX above, although the weight percentage of aluminum is 0 to 35, the upper limit of this range is subject to the limit that the ratio of aluminum to nickel does not greatly exceed the atomic ratio of 1: 1. The atomic weight ratio of aluminum to nickel is about 41%, and the weight percentage of the aluminum in this example does not significantly exceed about 41%, which is the weight percentage of nickel in this configuration.

Example X-IX

Magnesium zirconate can be replaced in part or in whole with respect to both the proportional weight percentage of calcium oxide and the corresponding weight percentage of zirconia that are thermally stable in each of Examples I-IX described above.

Example XIX-XX '

Configurations a, b, e and f of Table A, each modified to include at least about 0.25% of the spherical fused silica weight as lubricant, are suitable examples for forming a deposition matrix coating on a flexible cast belt.

The preferred minimum deposition thickness of the deposited matrix protective insulation coating for use in flexible metal continuous casting belts 10 and 20 (FIG. 2) is about 0.002 inches (0.05 mm), which is the grit-blasted problem. This is the average thickness of the peaks on the belt surface and is usually measured by a magnetic thickness gauge in this way. However, an advantage can be obtained by using a matrix coating of about 0.0015 inches (0.038 mm) thick.

Thermal spray coatings less than 0.002 inches (0.05 mm) thick are useful when non-wetting is more important than thermal insulation. Therefore, the practical lower limit for the thickness is not clear. Several times the thickness of 0.002 inches is sometimes useful for extraordinary insulation because the coating of the present invention is uneven and can withstand many bends in the pulley (roller) circumference of the continuous casting machine.

However, thicker thicknesses are dependent on the casting process, so thicker thicknesses do not depend on processes where coating debris significantly degrades the quality of the casting, such as in continuous casting of flexible belts, particularly copper wire bars, for fine wire drawing. It is not necessarily better. The 0.015 inch (0.4 mm) thickness is easily produced and the surface is uneven. However, the manufacturing cost of such thickness coatings is also a limiting factor.

The insulation can be adjusted with the thermally welded matrix belt sheath and the accuracy that can be provided by itself is desirable, as well as allowing the planned ratio of insulation between the belts 10 and 20 and the edge dams 16 and 18 to be planned. do. In other words, an optimal comparative heat flux density comparable to the heat flux to the edge dams 16 and 18 can be clouded through the belts 10 and 20. On the one hand, the precise balance of heat flux density on a wide belt surface with heat flux density on a relatively narrow moving edge dam is more than 1/4 inch (6 mm) thick and is important for producing cast metal slabs of first-class metallic quality: See US Patent Application No. 493,359, filed May 10, 1983, which is incorporated herein by reference.

This publication explains the importance of the balance of heat flux density between a wide belt mold surface and a narrow edge dam mold surface. To achieve a relative balance of heat dissipation (heat flux), the thickness of the coating on the belt must be adjusted to match the coating of the same composition on the edge dam block. Metals are usually better thermal conductors than nonmetals; The ratio of metal to nonmetal in the deposition matrix coating should be adjusted to control the conductivity. For example, the thermal conductivity of nichrome (80 wt% Ni, 20 wt% Cr) is about 10 times that of zirconia. In addition, the metal component itself in the matrix coating should also be selected according to the thermal conductivity or insulation value and the concentration of the relatively low conductivity metal should be adjusted for the metal concentration of high conductivity. The thermal conductivity of nichrome is about one quarter of that of nickel or some low nickel alloys.

The invention is applied to edge dam blocks in order to obtain similar advantages to those obtained for belts. However, according to the above patent application relating to the insulation of the edge dam block, more insulation is required at the edge dam block than at the belt periphery. This difference (greater thermal insulation) is achieved by providing a larger thickness of the thermal spray deposition matrix coating insulation, although compositional ratios can be used to adjust and balance heat flux.

[Machine for Forming Coating of Weld Matrix on Belt]

3 and 4 show a machine for employing a method of providing a sheath. The two circular cylindrical pulleys or rolls 34 and 36 have parallel horizontal axes. This horizontal axis lies on the same horizontal plane for convenience.

The idle pulley 34 is installed on the support 38 which is movable on the wheels 40 and 41 rolling on the rails 42 and 44 to adjust the belts of different lengths. The rail 42 is an inverted V-shaped steel angle having a downward leg, and the wheel 40 has an outer circumferential groove engaged with the ridge of the rail. Rail 44 is a flat bar. This rail is mounted on the bed structure 46. This rail is long enough to accommodate the longest belt to be covered.

The belt 10 is located around these pulleys and is subjected to tension. This tensile force is exerted by the double acting hydraulic cylinder 48 in line with the rigid tubular spacer 50. The spacer 50 is removed and replaced with a longer or shorter spacer depending on the range of belt lengths to be covered. The cylinder 48 is fixed on the center line in the horizontal length direction between the pulleys 34 and 36 to avoid rotational torque on the idle pulley and its support rail. The cylinder 48 is fixedly mounted on a rigid arm 58 protruding from the support 52. The tubular spacer 50 is secured to a similar rigid arm (not shown) that protrudes from the support 38.

Since one side of the machine must be open for belt fastening and removal, the pulleys 34 and 36 are driven by two bearings 54 and 56 on each pulley shaft 57 to absorb the overhung load. It is a cantilever beam from the supports 38 and 52. Although tensile stress is not a critical factor, the purpose of tensile stress is only to (1) drive and steer the belt and (2) process the machine to allow the belt to cool where the thermal spray flames strike the belt. Since the belt was pressed against the pulley 36 at the end, a stress of approximately 2200 pounds (1000 kg) per rich (upper and lower limit) of the belt was applied to achieve a total stress of 4400 pounds (2000 kg). The side of the machine where the belt is inserted and removed is called the "outer plate" side and the side near the supports 38 and 52 is called the "inner plate" side.

The four-way hydraulic valve (60) controls the stress. Under pressure, hydraulic oil emerges from pump 62. The limit switch 64 with the upright probe 65 senses the edge of the belt and emits a beep when the belt is stretched too far towards the inner plate, ie too close to the support.

While the traverse of the thermal spray gun 66 is slow, the belt 10 usually rotates relatively fast, and thus the boundary of the path overlaps, resulting in a pattern of a deposition path such as a screw thread or a spiral pattern.

This spiral feed passage is the preferred method because the start and end of the feed can be advantageously carried out outside the casting belt's margin, i.e. outside the casting zone, but the position and effect of the start and end of the feed is not critical. (36) is a statue of 30 to 50 feet per minute (9-15 m) in oxygen acetylene thermal spraying and approximately 100 feeds per minute in plasma thermal spraying by means of several drives inside the support (52) at the process end. Is rotated at a predetermined circumferential speed. However, speeds beyond much of this above range may be appropriate in some circumstances.

For example, the thermal spray gun 66 can reciprocate quickly across the belt like a shuttle while the belt rotates slowly or preferably the belt advances forward with each pass of the “shuttle”. However, uniformly covering the belt circumference in the case of start and stop can be easily achieved by this shuttle method.

Current preferred methods involving relatively rapid rotation of the belt as described above result in belt sagging to the inner or outer plate on the pulley without proper adjustment or delivery. A preferred countermeasure against current belt sagging is to allow the shaft 68 to tilt slightly upward or downward in a plate perpendicular to the belt's vertical richness, slightly obliquely turning the cantilever's idle pulley 34 in the vertical plate. The Row Inclination Adjuster is described in US Pat. No. 3,123,874, which is incorporated herein by reference. In the roll inclination adjustment, the manual adjustment screw 70 is provided to move the bearing 54 upward or downward to incline the shaft as necessary to prevent the belt from excessively sagging to either side.

Details of the fixing of the idle pulley 34 is as follows. The moment due to tension of the belt on the cantilever pulley 34 inside the battery underground housing 38 is absorbed from the pulley shaft 57 by two self-aligning pulley shaft bearings 54 and 56. do. The bearing 54 closest to FIG. 4 is enclosed in a right angle block 74 which is slidable up and down between the jibs 76.

The movable block 74 tends to be lifted by the weight of the cantilever pulley 34 axially supported by the bearing 56 fixed to the block 77, but the above-mentioned manual threaded thread is connected to the yoke 78. The adjusting screw 70 limits the rise of the block 74.

The hardening wear plate 80 on the block 74 prevents abrasion at the end of the adjustment screw 70. The jib 76 is fixed to the support frame plates 85 and 87 which are welded to the block 77. The plates 85 and 87 are also welded to the yoke 78 and the pair of angle members 89. The arrangement of the pulley shaft 68 in the horizontal plate, i.e. the arrangement of the pulley shaft in the plate parallel to the vertical reach of the belt, is screwed to a firmly fixed angle 84 which is in turn fixed to the base plate 86 which is part of the support 38. This is achieved by means of four specialized screws (only three are shown; 81, 82, 83). Angle members 89 on plates 85 and 87 include studs welded to the base plate and extend up through slots extending to the flanges of angle members 89, each with studs and washers and nuts. The stud assembly 91 is fixed to the base plate 86.

The thermal spray gun 66 is mounted toward the belt 10 in which the belt 10 turns and contacts the pulley 36 at the process end of the machine. This pulley is cooled, which is controlled by water flowing through the pulley by means of an axially mounted connector 88 (only one is shown) and hoseline 93. It is convenient to cool both pulleys, but not up to idle pulley 34. Cooling the work pulley 36 in this way prevents the pulley and belt from overheating. When the coolant is supplied at a cool and very high flow rate, the work pulley 36 is too cold, eventually condensing atmospheric moisture on the belt to form water. Such condensation should always be avoided by preventing the adhesion of the sprayed material. It is advantageous to allow the coolant to flow through the hoseline 93 only when power is transmitted to the pulley. Controlling the coolant to flow only when the belt rotates is controlled by placing a solenoid control valve (not shown) in the hoseline 93 which supplies the pulley coolant. The solenoid valve receives power from the same switch that transmits power to the pulley drive.

The thermal spray gun 66 traverses the full width or part of the belt by the nut 90 engaged with the lead screw 92 rotating at a predetermined speed by the drive device 94 of variable speed. The assemblies 92, 94 are supported by upright racks 96 and the transfer nut 90 is guided by a carriage 98 which moves along a guideway 99, such as a guide rod. The preferred traverse speed is determined by the width of the spray sprayed in one pass, the feed rate of the belt and the overall length of the belt. Naturally, longer belts require more time to pass through the pull lead, and therefore require a slower movement of the thermal gun 66 than shorter belts. The general range of travel speeds per revolution of the belt is 3/4 to 11/4 inches (38 to 63 mm) per belt revolution, but a wide range of useful feed rates should be provided for the gun 66.

For example, to adopt the above scheme of making a fire brigade a kind of shuttle, traverse speeds per minute and feet are required. There are several reasons why there is no strict speed limit of belt rotation or total traverse. Motes caused by overuse are effectively picked up. The machine is equipped with drainage and cleaning equipment to collect these dusts. Air containing dust oversprayed through the hood 100 extending over the entire traverse range of the spray gun 66 near the work pulley 36 is sucked out by a suction blower driven by a motor 102. . This air is sent out through a perforated and continuously wet metal baffle device installed in the housing 104. The hole in this wet baffle device is about 1/16 inch (1.5 mm). The filtered and washed air is finally discharged through the discharge duct 106. The hood 100 has a lip 107 projecting downward from the rear of the work pulley 36. The downwardly projected drip 107 is several inches above the top of the housing 105 of the traversing thermal gun 66.

At the point of thermal spray impact, the belt expands enough to float away from the pulley due to heating, resulting in a local separation between the belt and the cooled pulley 36. This loss of cooling contact may eventually result in local overheating of the belt.

Another method of cooling the belt is to surround the pulley 36 with a jacket, which is a suitably heat resistant material which is continuously moistened and is preferably of some elasticity (e.g. silicone rubber mat, glass fiber mat or a combination thereof). It is a wrap. The purpose is to provide a fibrous or porous surface having a controlled amount of water or aqueous coolant on the back of the cast belt. The moisture barrier so attached to the back of the belt cools the belt to prevent overheating. This cooling effect is believed to be mainly due to the water acting as a heat transfer medium between the belt and the water cooling pulley 36. A presently preferred method of providing belt cooling by the cooled work pulley 36 is a mop-like cloth or fiber bundle 109 which is about the same as the width of the belt and is in contact with the belt and is wet. ). This wet, porous fibrous bundle 109 is positioned in contact with the lower rich of the belt, which the belt approaches to an uncoated work pulley 36 made of steel. The belt conveying direction and the pulley rotation direction and the third and fourth figures are shown by arrows 111 and 115. The fibrous belt cooler 109 is continuously wetted as necessary to ensure that the belt does not reach temperatures above 450 ^° F.

Another belt coater, a machine with four pulleys, is shown in FIG. This improved machine employs two idle pulleys 108 and 110 extending from the support 38 'and a pair of work pulleys 112 and 114 extending from the support 52'. At least one of the pulleys 112 and 114 is a drive pulley. The machine belt with four pulleys does not come into contact with the pulleys, but because they are covered at the flat part of the casting belts where the casting belts can be adjacent to other cooling means from the back or to a coolant such as an aqueous solution, Allows for more reliable cooling of the belt. Excessive cooling by methods such as adding a large amount of cooling water is undesirable because of the result of condensation of atmospheric moisture on the belt surface to be flame sprayed. Condensed moisture prevents adhesion of the coating. In addition, treatment of excess water will be a problem if a significant amount of water is used. Water should not be allowed to come into contact with the belt surface to be thermally sprayed on the belt.

For this reason, water or aqueous solution is preferably applied by means of a nozzle 116 that produces fine thermal spraying or a porous wiping device such as a fibrous bundle or " muff " These fine spray nozzles 116 or porous wiping bundles or muffs are arranged in parallel with the thermal spray gun 66 and on the thermal spray gun 66 by means of a second screw 118 in order to always face the gun 66. It is preferable to act on the back of the belt via a restricted area moved by the carriage 117 which is arranged to be opposed to and conveyed. The spray from the nozzle 116 should not be fine enough to form a fog unless a second suction hood is installed to prevent the fog from running around the front of the belt. The carriage 117 for the nozzle 116 is synchronous with that driven from the other screw shaft 92 for the gun 66, which in turn is driven by the chain sprocket 122 so that the chiller 116 is always a traverse gun. It is fixedly mounted on a nut 120 on a screw 118 which stays against 66. The branched guide 124 sliding along the frame member 126 prevents the nozzle carriage 117 from rotating.

In this machine, four, not three, pulleys are usually needed to provide uniform steering effects at both ends of the machine. The steering method is similar to the principle described in US Pat. No. 3,310,849, which is incorporated herein by reference.

Referring to FIG. 3, it has been found that the wet, porous, wiping coolant 109 is very successful in avoiding overheating of the belt. The work pulley 36 is not covered with a surface and is appropriately cooled by the cooling water flowing through the connecting device 88 with the hose line 93. Moreover, the coating of water is applied to the inner belt surface by a wet, porous, fibrous bundle 109. In order to form such a thin and sprayed water coating on the back, as much aqueous detergent as necessary is added to the porous bundle (109). This system and method using wet, porous, belt wiping bundles 109 added to a suitably cooled uncoated work pulley 36 has been found to work very successfully and is considered optimal at present.

Variable speed drive 94 includes an electric motor 128 (shown most clearly in FIG. 6) that drives at a variable speed and includes, for example, a reversible mechanical transmission 130, such as a cone drive. The handle 132 is used to adjust the output speed and to reverse the direction of the output drive. The dial 134 represents the adjusted speed and direction. This mechanical transmission 130 includes a right angle gear and the output from the transmission operates to drive the sprocket and chain drive 136 located in the protective housing and to drive the sprocket fixed to the end of the lead screw 92. Moreover, the speed and direction of the lead screw 92 can be adjusted by the handle 132. After the adjustment is made, the lead screw 92 rotates constantly in the adjusted direction at the adjusted speed until the next adjustment is made. Such variable speed reversible drive 94 is manufactured industrially, for example, by Graham, Milwaukee, Wisconsin.

3 and 5 show that the drive device 94 is mounted on a shelf fixed to the upright red 140 of the fixed rack 96 with the base frame 142.

Metallic and nonmetallic powder components are capable of, for example, screw locking or latch locking and are thoroughly mixed with a stirring impeller in a closed vessel with a removable lid. The purpose is to obtain a complete and uniform mixture and to prevent segregation before feeding the mixture into the powder feed passage leading to the nozzle of the thermal spray gun 66.

3 and 5, this thermal spray gun 66 represents an oxygen acetylene rifles and oxygen and acetylene are supplied through a pair of hose lines 144 and 146, respectively. Oxygen and acetylene are mixed in the gun 66 and with a powder mixture to be sprayed out from the axial outlet, in an annular nozzle 148 having multiple spouts arranged around the central axial outlet facing forward. Supplied. One way in which the powder is fed to the gun 66 is to mount a hopper (not shown) on top of the gun housing 105.

The hopper has a retractable lid and includes an electric motor driven mixing stirrer impeller member for maintaining a complete and uniformly mixed powder. The hopper wall is vibrated by an electrically driven vibrator to prevent the powder mixture from "bridging" or "compacting" in the hopper. The metering discharge mechanism measures the flow rate of the powder mixture which is fed from the bottom outlet of the hopper to the powder feed passage leading to the nozzle 148 of the gun, which metering discharge consists of a feed screw with a variable speed drive, for example. The presently preferred method of supplying the powder mixture to the gun 66 is to use powder mixtures and feeders that are spaced apart as shown at 150 in FIGS. 3 and 5. The device includes a control console 152 and includes a container 154 into which the powder mixture is loaded by removing screws on the lid 156. The powdered ingredients are thoroughly mixed before being loaded into the container 154 and stirred and vibrated to prevent layering, segregation, compacting or bridging in the container.

The interior of this vessel 154 is adjustablely pressurized to the vessel pressure indicated by the dial 158 on the console 152 by an inert gas such as nitrogen. This pressure pushes the powder mixture from the vessel towards the outlet.

This outlet is in communication with the powder feed hoseline 160 connected to the gun 66 and in axial passageway leading to the central outlet of the nozzle 148. Increasing the vessel pressure indicated by the dial 158 increases the powder feed rate, i.e. the amount of powder mixture supplied to the vessel outlet through the hoseline 160, on the contrary, decreasing the vessel pressure decreases the powder feed rate. .

The speed of the powder mixture through the powder feed hose line 160 can be controlled independently of the feed rate and is indicated by the gas flow meter 159. The gas flow meter 159 represents the speed at which the inert gas flows through the powder supply line 160. This inert gas flow makes the powder mixture close to the vessel outlet into a fluidized bed and conveys the fluidized powder mixture through the line 160 of the central axial outlet to the nozzle 148 of the gun 66.

The oxygen and acetylene feed tanks (not shown) each have a conventional shut-off valve, each with a manually adjustable flow meter for independently adjusting the feed rate of oxygen and acetylene through the respective lines 144 and 146. Located downstream of the shutoff valve.

Manually operated valves in the gun 66 simultaneously open and close flow through both lines 144 and 146. The gun 66 is manually ignited by the spike striker. The electrical switch in the gun 66 is connected via an electrical cable 162 and a control console for opening and closing the mixing and feeding device 150 according to the wishes of the operator located behind the gun housing 105. The operator can therefore open and ignite the gun. Next, when desired, the operator activates the electrical switch of the mixing and feeding device 150 such that the mixing and feeding device supplies the powder mixture to the gun. One example of a suitable oxygen acetylene flame spray 66 and mixing and feeding device 150 is the product of Eutectic-Castrin, Flushing, New York, under the trademark TERODYN System 3000. Another example of a suitable oxygen acetylene flame spray gun 66 and mixing and feeding device is an oxygen acetylene flame spray gun with a hopper mixing and feeding device mounted directly to the total housing 105 as described above.

This hopper requires the powder mixture to be reloaded at intervals of about 10 minutes during operation; On the other hand, the container 154 requires the powder mixture to be reloaded at about one hour intervals during operation, so it is now preferred to use a spaced device 150.

As described above, the coated belt 10 or 20 may be rotated on one side or while it is rotated around the pulley rolls 34 and 36 (FIG. 3) or pulley rolls 108, 110, 112 and 114 (FIG. 5). There is a tendency to arise or rise to the other side (corner direction). Therefore, as described above, it is necessary to turn the steering screw 70 to take measures against the rising by the steering belt.

Lateral sagging or rise of such belts and steering devices cause problems with the uniformity requirements of the matrix coating to be applied.

If the thermal spray gun traverses uniformly and uniformly over the frame of the applicator, as the lead screw 92 is originally forced to do, non-uniform traverse behavior of the gun to the belt will occur. The nonuniform relative behavior between the gun and the belt is that more coverage is done in one area on the belt and less in the other area.

The presently preferred device and system shown in FIG. 6 has been advantageously employed to ensure that the thermal spray gun traverses uniformly and continuously uniformly over the belts 10 and 20 to be covered despite lateral (corner) belt behavior. .

The upright lag 140 of the rack 96 shown in FIG. 3 and FIG. 5 forms a rack assembly 94 'which has been blocked by the shelf 138 and is laterally floating; In other words, the assembly can move freely back and forth in a direction parallel to the axis of the lead screw 92 so that any side (corner direction) behavior of the belt can be followed as described later.

The entire thermal screw is a lead screw 92; Its drive 94, support frame 96 'thermal spray gun and its carriage 98 and float to accommodate lateral movement. In other words, this float allows the lead screw and the gun to move freely transversely with respect to the surface of the cast belt to be coated; In other words, it is allowed to move in the horizontal direction parallel to the axis of the lead screw 92.

There is a fixed horizontal track frame 164 extending parallel to the axis of the lead screw 92 and the working roller 36. The track frame 164 is supported and fixed to the fixed hood 100 by brackets 166 and 168, for example by welding of these brackets.

This track frame 164 has a hollow rectangular shape as shown at the left end in FIG. On the top surface of the track frame 164 is an extended blocking cavity or slot 170 which extends to the left (outer) end of the track frame. The removable plate 172 is connected across the gap at the left end of the throat 170 and is secured by four machine screws, washers and nuts 174.

The track frame 164 has a track parallel to the axis of the lead screw 92, and a pair of parallel inward bending flange tracks 176 and 178 located on the same horizontal plane that acts as a track and spaced apart. have.

Moving along these parallel track paths is a pair of carriages 180 and 182 with wheels protruding outwards on both sides forming a plate welded to the top of the floating frame 96 '. Each carriage 180 and 182 has four support wheels 184 having axes parallel to a plane perpendicular to the axis of the lead screw 92. There are two wheels 184 on each side of each pallet so that each pallet has two wheels rolling along the respective trackways 176 and 178 to support the floating frame 96 '.

In addition to these four support wheels 184, each carriage 180 and 182 is provided with one guide wheel 186 about a vertical axis. The guide wheels 186 guide the movable frame 96 'for directing the carriage to move parallel to the surface of the belt in the area to be thermally thermally sprayed, to guide the corners of the respective trackways 176 and 178. It is installed under each carriage 180 and 182 to roll along.

The inner plate (right) end of the lead screw 92 is fixed to the bearing assembly 190 bolted to the lower surface of the movable frame 96 'as shown in FIG. The movable frame 96 'extends just behind the position of the bearing 190.

Thus, as a whole, the movable frame 96 'has an "L" shape, with the long portions of the L-shape extending horizontally and the short portions extending vertically downward so that the lower end of the vertical lag and the platform or shelf 138 Sticks with.

In order to detect the edges of the belt 10 or 20 to be covered, a movable frame 96 'between the carriages 180 and 182 is mounted on the footpad and inverted " U " support member 192 fixed at 193 on top. There is a sensing roller 196 which is fixed to the arm member 194 carried by it and has a vertical axis.

This inverted " U " shaped support member 192 has a width and height sufficient to clean and fully reach the hood 100 in all positions and its upright lag 195 is capable of opening the clearance slot 170. Stretched over. The tension spring 188 extends between the fixing bracket 168 and the support member 192 so that the sensing roller 196 maintains contact with the inner plate (right side) of the belt (and follows the inner plate). Make sure 96 'is facing to the left (outer plate direction).

As a result, the spring 188 and the sensing roller 196 allow the thermal spray assembly to follow the belt despite any edge sagging or rising of the belt upon rotation of the belt. If there is no turning of the lead screw, the thermal spray path on the belt surface will be aligned at a fixed distance from the detected edge of the belt despite the transverse (edge) movement of the belt.

Now, when a uniform lead screw that causes the movement of the spray gun is superimposed on the above-mentioned auto-sensed belt edges, the result is a uniform covering behavior despite any lateral (edge) movement of the belt on both sides. Serve In other words, when the belt rotates and the lead screw 92 moves the gun in relation to the floating frame 97 ', the resulting thermal spray root movement is always at a uniform distance from each other and on the belt surface. In a foreseeable aspect, the thermal sprays are mixed with each other to eventually provide a uniform thickness coating despite any transverse (edge) movement on the belt, i.e. despite any transverse shaking of the rotating belt.

Uniform provision of this desired coating is conveniently achieved regardless of the side lift of the belt or the steering of the belt to correct the rise. This uniformity is conveniently achieved in spite of any camber that may be inadvertently present at the edge of the belt. All that is required for the close pass of the spray is that they are spaced apart from each other by a uniform predetermined distance for proper mixing. Because they are straight, that is, they are in a complete spiral passage on the belt surface is not a requirement.

In order to allow the fork-shaped gun carriage 98 to move exactly in proportion to the floating frame 96 ', the carriage carriage 98 is a chassis 199 with a pair of wheels 198 having a vertical axis. It includes. This wheel 198 rolls along a track 99 or a guide machined accurately on the side of the horizontal leg of the movable frame 96 '.

A pair of wheels (not shown) on the other side of the chassis 199 roll along a similarly processed guideway on the opposite side of the horizontal leg of the movable frame 96 '. Therefore, the wheel 198 of the carriage 98 keeps the carriage 98 correctly aligned to keep the total housing 105 accurately spaced from the belt surface as the lead screw 92 rotates. Is in a straddle relationship with the frame 96 '. The other pair of wheels 200 (only one shown) attached to the opposite side of the chassis 199 on the horizontal axis is movable frame 96 'to stabilize the total carrier 98 to prevent the total carrier from oscillating. Roll along the guideway precisely machined on the lower surface of the horizontal leg of the machine.

The brace 202 extends down from the pallet and is adjustable in the 204 position on the side of the total housing 105. In FIG. 6, the observer sees the back side of the total housing 105 because the nozzle of the total housing is directed at the belt.

Although the thermal spray gun is directed at the belt when the belt passes through the roller 36 in FIG. 6, the transverse floating belt sensing thermal spray apparatus in FIG. 6 is also applied to an applicator with four pulleys as shown in FIG. It should be appreciated that it can be conveniently adopted.

The roller 196 acts as a detector at the belt edge position and the spring 188 acts as a synchronous means for moving the movable frame 96 'in response to the sensing activity of the roller 196. Other belt edge sensing means such as, for example, sliders, electrical grounding, light beams, photocells or pneumatic thermal spray position detectors, magnetic sensors, etc., are responsive to the sensing means, e. It can be used in parallel with other synchronization means such as synchronization means.

Furthermore, instead of detecting the belt edges, it is possible to apply or paint a narrow band of contrasting colors along the margin near the belt edges and then detect the bands. However, since the edges of the steel belt are very clear in nature, it has been found that this complete mechanical sensing and synchronous means for performing automatic belt detection of the entire transverse floating thermal spray collector is very practical, durable and very reliable. .

The present invention, which thermally sprays heat-resistant metals and refractory non-metals on a single layer deposition matrix protective coating of a powder mixture, can satisfy all of the following essential and desirable conditions. The deposition matrix coating is (1) adhesive to the flexible base metal or side dam blocks of the belt; (2) provide adequate thermal insulation; (3) resistant to mechanical damage, ie delamination or wear; (4) resistant to thermal shock; (5) provide a desired finish surface for the casting; (6) has good non-wetting properties for molten metal castings; (7) provide the correct ratio of insulation between the belt and the lateral dams; (8) there is a desirable porosity throughout the matrix coating; (9) because of its surface properties, it is coordinated with an additional and minimal temporary top coat such as oil or carbon or mixtures thereof; (10) It may be practically implemented by means of easy construction and easily operated machines as described.

In accordance with conventional relationships in the use of belt casting machines, the user has found that it is desirable and desirable to apply a temporary top coat on the weld matrix coating belt. For example, it has been found that temporary coatings provided with colloidal graphite and dried with an aqueous or solvent solution are suitable for use in matrix coated belts for casting copper products (P).

Judging from previous experiments, it is thought that amorphous carbon or assays performed temporarily with colloidal suspension can replace graphite normal coating.

If the article P is a cast aluminum slab, diatom silica may be contained in this temporary top coat. In the casting of copper, a small amount of oil may be desired and may not be sprayed onto the deposition matrix coating of the new belt, not so much as to appear wet or cause decomposition of the oil. In casting copper rods to be used for drawing wires, the life of the top and bottom is almost doubled when the belt is coated with a weld matrix according to the invention. Surface quality is considerably improved over the prior art, in part due to the use of much less oil or normal coating, reducing the porosity associated with hydrogen in the casting. The improved metallization of the copper rods indicates that there is improved drawability.

In an early test of copper rod casting, the matrix coating of the first embodiment was used only on the top belt 20. It was about 0.002 inches thick on a strongly rolled low carbon titanium steel belt that was 0.044 inches thick. This casting was stopped after 3 hours for reasons not related to belt coating which are still under excellent conditions. Initially no graphite precoat was used, and copper was slightly raised. The next casting on this belt was carried out 24 hours with two interruptions not related to belt covering. The amount of oil applied to the belts in casting copper rods in twin belt machines was reduced compared to the conventional ones with good results. The test was terminated after 24 hours for reasons not related to belt coating.

The copper rod casting test was repeated with the matrix-coated low carbon steel upper belt 20 of the first embodiment without the titanium of the second tumbler. The results were as good as with titanium steel belts, and such good results were not expected because of the opposite results from previous tests that attempted to cast copper rods on titanium-free steel belts. Conventional experience suggests that micro cracks will occur in the titanium free belt after 8 to 10 hours of repeated contact with molten copper and repeated bending. Such cracking did not appear in the titanium-free matrix coatings tested for 8-10 hours.

Another copper rod casting test was conducted with the deposition matrix coating according to the third embodiment. This coating was applied on a strongly rolled low carbon titanium steel belt that was 0.044 inches thick. This time, the welding matrix covering belt was used as the upper and lower belts. Initially, after applying some oil to the top belt, it was necessary to wipe the top belt about 3 times per hour to rule out slight swelling. The results were also excellent, including the longest belt life we observed in copper casting. The lifespan of the upper and lower belts is almost doubled.

An example of the advantages of the specific invention is the experimental casting of aluminum alloys. The surface improvement of the metal to be cast is remarkable. Rosettes and streaks previously observed during the casting process are removed from the top and bottom surfaces of the casting slab. Rejected materials are greatly reduced. The weld matrix cladding belts are in good condition beyond the useful life of conventional belts. The edges of the cast slab were excellent due to the harmonious heat transfer between the edges and the belts by using insulating coating. Experience has shown that, for ease of use, an endless flexible cast belt having a deposition matrix coating thereon according to the present invention is repeatedly bent around a pulley roll having a diameter of 20 inches (508 mm) without peeling of the coating. You must be able to lose.

Although the examples and observations described herein result from the practice of the experimental field of matrix coated belts in which molten copper or molten aluminum and aluminum and alloy are cast thereon and casting 14 inches vertically before molten steel impacts the coated belt Although the results of the experiment with molten steel tapping the fixed floating portion of the belt is shown, the present invention can be applied to continuous casting of any metal or alloy with a melting temperature equal to or lower than the steel.

Although preferred embodiments of the present invention have been described in detail herein, it should be understood that embodiments of the present invention have been described for purposes of illustration. This disclosure is not intended to limit the scope of the invention.

Claims (41)

A method of providing protection and insulating coating on the metal surface of a continuous casting machine in contact with molten metal during casting, ie on the clean and rough surface of an endless flexible metal casting belt for a continuous casting machine, comprising: a) at the temperature of the molten metal to be cast; Heat resistance and resistance to heat cycles, b) thermal adhesion to the metal surface, c) slight ductility to withstand repeated bending around pulley rolls, d) thermal spray conditions and continuous to avoid inadvertent oxidation Oxidation resistance under casting conditions, e) providing both a metallic material having a coefficient of thermal expansion compatible with a predetermined nonmetallic refractory and a predetermined nonmetallic refractory in a readily heat-melt state, and uniformly mixed with the nonmetallic refractory. At least 4% of the total volume of the coating to improve the non-wetting properties of the coating by molten metal by thermally welding a coating made of a metallic material to the metal surface Protection on the clean and rough surface of the metal surface of the continuous casting machine or the endless flexible metal casting belt for the continuous casting machine, which is in contact with molten metal during casting, characterized by forming a protective and insulating coating having a desirable accessible porosity. How to provide insulation coating. The nonmetallic refractory according to claim 1, wherein the nonmetallic refractory is formed by the thermal spraying of the powder mixture containing (1) a heat resistant metal material and (2) an insulating nonmetallic refractory, and subsequent thermal spraying of the powder mixture onto the surface. The metal material is dispersed in a continuous matrix of the metal material and the nonmetal refractory is held in the continuous matrix of the metal material and fixed to the surface of the endless flexible metal casting belt to form a continuous matrix of the metal material. A method of protection and insulation, characterized by being contained in a mixture. The composition of claim 2, comprising 38 to 90% by weight of the coating, the metal material selected from the group consisting of nickel, cobalt, iron and titanium or mixtures thereof, and 10 to 62% by weight of the coating. Characterized in that the nonmetallic refractory selected from the group consisting of graphite, zirconia, magnesia, zirconate, silica and alumina or mixtures thereof is made into a powder, and the powder is uniformly mixed before the welding process to the surface made of thermal spraying. Way. 4. The metallurgical material of claim 3, wherein the metallic material contains nickel as a main component, the nonmetallic refractory comprises powdered zirconia as the main component, and the thermal spraying is carried out at a distance of at least 3 inches (76 mm) at 30 to 50 feet per minute (9 to 15). Meter) traverse speed. The method of claim 2, wherein the protective, insulating coating has a matrix structure comprising a continuous network of metal material, non-metal refractory is dispersed throughout the matrix, the thickness range of the coating is 0.0015 inches (0.04mm) ) To about 0.015 inch (0.4 mm). The method of claim 5, wherein the specific gravity ratio of the metal material to the non-metal refractory is in the range of 1: 1 to 4: 1. 7. The method of claim 6, wherein the homogeneous mixture of metallic material and nonmetallic refractory comprises a heat stabilizer selected from the group consisting of itrima, magnesia and lime. 8. The method of claim 7, wherein the homogeneous mixture of metallic material and non-metallic refractory comprises spherical fused silica as a fluidity enhancing lubricant. The method of claim 2 wherein the powder mixture consists of one composition selected from the following compositions (% by weight): Composition I 4 to 5 aluminum, 2 to 3 molybdenum, 55 to 57.5 nickel (including trace impurities), 35 Zirconia, Calcium oxide in 1.5 to 2 zirconia; Composition II 6 aluminum, 4 molybdenum, 52 nickel (with trace impurities), 22 to 23 zirconia, Calcium oxide in 1 to 1.5 zirconia, 13 to 14.8 graphite, 0.2 to 0.5 spherical fumed silica; Composition III 14 chrome, 54 nickel (with trace impurities), 54 nickel (with trace impurities), 29.8 to 30.4 zirconia, Calcium oxide in 1.4 to 1.6 zirconia, 0.2 to 0.6 spherical fumed silica; or Composition IV 38 to 90 metals containing less than 35 aluminum and residual nickel (including trace impurities) and 40 or less graphite, 0.3 to 0.8 spherical fumed silica, 4 to 20 limes and residues in total amount of zirconia and lime 10-62 nonmetallic components including zirconia. 2. The moving mold of the casting machine according to claim 1, wherein the upper and lower portions are determined by the upper and lower matrix coated endless flexible metal belts, and the side surfaces are determined by the first and second matrix coated side dams whose main components are metals. A process for relatively distributing a heat flux density between the belt surface and the side dams in a casting machine for continuously casting a metal product directly from the molten metal into which the molten metal is introduced; The side dam of the endless flexible belt is covered with a matrix coating, and the process of relatively distributing the density of the heat flux determines the density of the heat flux through the belt, and the next process, i. Adjusting the thickness of the matrix coating provided on the belt in comparison with, b) adjusting the content of the metallic material relative to the content of the nonmetallic material in at least one of the matrix coatings, and c) at least one of the matrix coatings. For the heat flux density to the lateral dam by at least one of the steps of adjusting the content of at least one metal having a relatively low thermal conductivity to the content of at least one metal having a higher thermal conductivity in the coating, And distributing the heat flux density through. In an endless flexible cast belt for use in a continuous metal casting machine for continuous casting of molten metal having protective and insulating coating deposited on its surface, the coating is uniformly dispersed in the metal material and the metal material. It consists of a non-metal refractory, the metal material is in the form of a matrix for holding, supporting and fixing the non-metal refractory on the belt surface, the protective and insulating coating is a total of the coating to improve the non-wetting of the coating to the molten metal Endless flexible cast belt, characterized by having an accessible porosity of more than 4% of the volume. 12. The method of claim 11, wherein the sheath is a) heat resistant to the temperature of the metal to be cast and resistance to heat cycles, b) heat adhesion to the belt surface, c) slightly to withstand repeated bending around the pulley roll. Ductility, d) oxidation resistance under thermal spraying conditions and continuous casting process conditions to avoid inadvertent oxidation, and e) a metallic material having a thermal expansion coefficient compatible with a predetermined nonmetallic refractory, Refractory is uniformly dispersed throughout the metal material and the metal material is an endless flexible cast belt, characterized in that in the form of a matrix for holding, supporting and fixing the non-metal refractory on the belt. 13. A metal material according to claim 12, selected from the group consisting of nickel, cobalt, iron and titanium or mixtures thereof and comprising 38 to 90% by weight of the coating, graphite, zirconia, magnesia, zirconate, silica and alumina or Non-metallic refractory selected from the group consisting of the mixture and constituting 10 to 62% by weight of the coating is made of powder and mixed with the powder prior to the welding process to the surface consisting of thermal spraying. belt. The metal material of claim 13, wherein the metallic material contains nickel as the main component, the nonmetallic refractory includes powdered zirconia as the main component, and the thermal spraying is at least 3 inches (7 mm) apart and 30 to 50 feet per minute (9 to 50 m / s). Endless flexible casting belt, characterized in that carried out at the traverse speed of min). The method of claim 12, wherein the coating has a matrix structure comprising a continuous network of metal material, non-metal refractory is dispersed throughout the matrix, the thickness range of the coating is 0.0015 inches (0.04mm) to 0.015 Endless flexible cast belt, characterized in that the inch (0.4mm). The range of specific gravity ratio of metal material to nonmetal refractory according to claim 15

: 1 to 4: 1 endless soluble cast belt, characterized in that. 17. The endless flexible cast belt of claim 16 wherein the homogeneous mixture of metallic material and nonmetallic refractory comprises a heat stabilizer selected from the group consisting of yttria, magnesia and lime. 18. The endless flexible cast belt of claim 17 wherein the homogeneous mixture of metallic material and non-metallic refractory comprises spherical fused silica as an improved flow lubricant. 13. The endless flexible cast belt according to claim 12, wherein the powder mixture is composed of one composition selected from the following compositions (wt%). Composition I 4 to 5 aluminum, 2 to 3 molybdenum, 55 to 57.5 nickel (including trace impurities), 35 Zirconia, Calcium oxide in 1.5 to 2 zirconia; Composition II 6 aluminum, 4 molybdenum, 52 nickel (with trace impurities), 22 to 23 zirconia, Calcium oxide in 1 to 1.5 zirconia, 13 to 14.8 graphite, 0.2 to 0.5 spherical fumed silica; Composition III 14 chrome, 54 nickel (with trace impurities), 29.8 to 30.4 zirconia, Calcium oxide in 1.4 to 1.6 zirconia, 0.2 to 0.6 spherical fumed silica; or Composition IV 38 to 90 metals containing less than 35 aluminum and residual nickel (including trace amounts of anhydrous) and 40 or less graphite, 0.3 to 0.8 spherical fumed silica, 4 to 20 limes in total amount of zirconia and lime; 10-62 nonmetallic component containing remainder zirconia. A method of casting molten metal in a continuous casting machine having an endless flexible metal casting belt, the method comprising casting between molten metal between the coated surfaces of the endless flexible metal belt according to claim 12 in the continuous casting machine. Method for casting molten metal in a continuous casting machine having an endless flexible metal casting belt, characterized in that. The method of claim 20 wherein the molten metal is selected from the group consisting of mild steel, copper and aluminum. A flowable composition for being deposited as a coating on a metal surface to provide protection and insulation coating on a metal surface of a continuous casting machine, comprising: a) heat resistance to the temperature of the metal to be cast and resistance to heat cycles; b C) a slight ductility to withstand repeated bending around the pulley roll; d) oxidation resistance under thermal spray conditions and continuous casting process conditions to avoid inadvertent oxidation; and e) Uniformly composed of 38 to 90% by weight of a metal material in an easily heat soluble form having a thermal expansion rate compatible with a predetermined nonmetallic refractory, and 2) 10 to 62% by weight of a nonmetal refractories in an easily heat meltable form. Flowable composition, characterized in that consisting of a mixed composition. 23. The flowable composition of claim 22 wherein the uniformly mixed composition is a powder mixture consisting of one composition selected from the following compositions (% by weight). Composition I 4 to 5 aluminum, 2 to 3 molybdenum, 55 to 57.5 nickel (including trace impurities), 35 Zirconia, Calcium oxide in 1.5 to 2 zirconia; Composition II 6 aluminum, 4 molybdenum, 52 nickel (with trace impurities), 22 to 23 zirconia, Calcium oxide in 1 to 1.5 zirconia, 13 to 14.8 graphite, 0.2 to 0.5 spherical fumed silica; Composition III 14 chrome, 54 nickel (with trace impurities), 29.8 to 30.4 zirconia, Calcium oxide in 1.4 to 1.6 zirconia, 0.2 to 0.6 spherical fumed silica; or Composition IV 38 to 90 metals containing less than 35 aluminum and residual nickel (including trace impurities) and 40 or less graphite, 0.3 to 0.8 spherical fumed silica, 4 to 20 limes and residues in total amount of zirconia and lime 10-62 nonmetallic components containing zirconia. A device for providing insulation and protective coating on an endless flexible cast belt, the apparatus comprising: a plurality of spaced cylindrical pulleys having parallel axes, at least one of the pulley rolls for rotating the cast belt around the pulley rolls; A driving device for rotating, a device for tightening the belt rotating the roll circumference, a device for steering the belt rotating the roll circumference, a thermal spray gun, and the gun to direct the belt from a predetermined distance And a device for supporting the gun and traversing the gun forward and backward with respect to the rotating belt. 25. The machine of claim 24, wherein the thermal spray gun is at least 5 inches away from the rotating belt. The apparatus according to claim 24, wherein the support and traverse device reverses the front and rear traverses of the thermal spray gun near the outer edge of the belt, which is an area intended to face molten metal. 26. The liquid spray gun of claim 25 wherein one of the cylindrical pulley rolls is a working roll, wherein the thermal spray gun is directed at the belt when the belt partially moves around the working roller circumference, and retains a controlled amount of liquid solution. And a continuously wetted heat-resistant jacket or sheath of porous or sponge material is fixed around the working roller for the purpose of cooling the back of the belt in the thermal spray impingement zone. 25. The bundle of fibers of claim 24 wherein one of the cylindrical pulley rolls is a work roll, and wherein the thermal spray gun is directed at the belt when the belt partially moves around the work roll, and the bundle of fibers continuously moistened and fixed Extending in the width of the casting belt to contact the back surface of the belt before contacting the working roller with the belt. 25. The system of claim 24, wherein there are at least four cylindrical pulley rolls, wherein the thermal spray gun is directed at the casting belt as the belt moves between a pair of the pulley rollers, and a cooling device cools the back of the casting belt. And a device for synchronously supporting and traversing the cooling nozzle with the thermal spray gun so as to face the thermal spray collision point. 25. The cooling bundle of claim 24, wherein there are at least four cylindrical pulley rolls, wherein the thermal spray gun is of a fibrous material that is directed at the cast belt and continuously wetted when the belt moves between the pair of pulley rolls. Is pressed against the back of the cast belt, which is opposite the thermal spray impact zone from the thermal spray gun. 30. The apparatus of claim 29, wherein the cooling device is a nozzle for applying coolant liquid or mist to the inner surface of the belt opposite to the heat-splashing zone from the gun. 32. The method of claim 31, wherein a lead screw traverses the thermal spray gun transversely with respect to a belt, another lead screw traverses the cooling nozzle, and the two lead screws synchronously move the nozzle with respect to the thermal spray gun. Apparatus which is mechanically interconnected for traversing the system. 31. The thermal spray gun of claim 30, wherein a lead screw traverses the thermal spray gun transverse to the belt, another lead screw traverses the wet fibrous mass, and the two lead screws traverse the wet spray gun and the wetting. Characterized in that they are mechanically interconnected to synchronously traverse the cold bundles of the material. 30. The apparatus of claim 29, wherein the cooling device is operatively associated with the driving device to stop cooling activity whenever the driving device is stopped. 30. The drive system of claim 29 wherein the drive rotates the belt at a relatively high speed around the pulley roll circumference, and the traverse device transverses at a relatively slow speed so that the path of thermal spray collision on the belt is spiraled. And traversing the thermal spray gun. 25. The apparatus of claim 24, wherein the sensing means senses the transverse position of the rotating belt, and wherein the device for supporting the gun and traversing back and forth is uniformly associated with the rotating belt regardless of the transverse movement of the rotating belt. And controlled by the sensing device to traverse a thermal spray gun. 37. The apparatus of claim 36, wherein the device for holding and traversing the gun is at least one track extending across the belt such that the thermal spray from the gun is parallel to the area of the belt where the thermal bombardment collides, transversely with respect to the belt. A conveying device freely movable along the track, a lead screw rotatably mounted on the conveying device extending parallel to the track, the lead screw for moving the gun so as to traverse the gun transversely with respect to the belt And a synchronizing means for moving the conveying device along the track in response to the sensed lateral position of the belt rotating under the control of the sensing device. 38. The device of claim 37, wherein the sensing means is a member for contacting the edge of the rotating belt, the supporting means extending from the sensing means to the conveying device to maintain the sensing means in a fixed position relative to the conveying device. And said synchronizing means pressurizes said conveying means in a direction along said track such that the sensing member is in contact with the edge of the rotating belt despite the lateral vibration of the rotating belt. 39. A spring according to claim 38, wherein said synchronization means is attached to said conveying means, one side of which is attached at a fixed position relative to the entire apparatus and the other side to press the conveying means in the direction along the track. And a member. 40. The roller of claim 39, wherein the sensing member is a roller having an axis extending perpendicular to the belt surface near the roller so that the roller can roll along an edge of the belt, wherein the spring member rotates in both directions. And the roller acts to roll in contact with the belt edge in order to track any lateral vibration of the belt. 37. The apparatus of claim 36, wherein the conveying means has a precise guide surface extending parallel to the lead screw and spaced apart from the lead screw, the gun having a carrier associated with the lead screw, the carrier having at least installed thereon. And a wheel, wherein the wheel rolls in contact with the precision surface to guide and stabilize the gun carrier when the gun carrier is traversed by the rotation of the lead screw.

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