Surface treatment of a metal surface of a metal part, such as a glassmaking mould, by cold spraying of a metal powder

Abstract

The present disclosure relates to a surface treatment method for treating a moulding surface (2) of a glassmaking mould (1). This surface treatment method comprises a step of cold spraying a metal powder (4) in the solid state onto the moulding surface (2) of the glassmaking mould (1) so as to obtain a solid deposit (5). It also comprises a step of machining the solid deposit (5) so as to obtain a coating. The present disclosure also relates to a metal powder, to a surface treatment machine and to a surface treatment facility for implementing such a method, as well as to a glassmaking mould obtained by means of such a method.

Description

[0001] DESCRIPTION

[0002] TITLE: Surface treatment of a metal surface of a metal part, such as a glassware mold, by cold spraying of a metal powder

[0003] TECHNICAL FIELD

[0004] This application generally concerns metal castings in the field of glassmaking, in particular cast iron, brass, bronze (and other alloys including copper and tin) or steel molds used to make glass objects such as bottles or, in general, any metal part likely to come into contact with the parison.

[0005] The present application relates more particularly to the surface treatment of the metal surface of these metal parts which comes into contact with the glass parison (or gob) during the manufacture of glass objects. It finds a particular, but not limiting, application in the surface treatment of the molding surfaces of the molds in order to improve the thermal and / or mechanical properties of the molds during the roughing and finishing phase.

[0006] STATE OF THE ART

[0007] The manufacture of a glass object, particularly hollow glass such as a bottle, is done in several stages.

[0008] During a first stage called roughing, viscous glass is melted (at a temperature between 700 °C and 1200 °C), poured in the form of a parison (drop), fed via a deflector and a distribution channel, into a mold, called a roughing mold. The viscous glass undergoes compression in the roughing mold and is then pierced in order to bring it into contact with the walls of the roughing mold and obtain a roughing. The roughing then has a temperature of up to 900 °C, depending on the area and thickness of the roughing.

[0009] Then, during a second stage called finishing, the blank thus formed is transferred into a finishing mold to be blown and give it its final shape. During contact between the blank and the finishing mold, a significant drop in temperature occurs as well as an elongation of the glass. The final product is obtained after this blowing stage. It then has a temperature of around 600°C.

[0010] Glassware molds thus have several functions.

[0011] First of all, glass molds have a thermal function by allowing the glass to cool. It is necessary that, upon leaving the blank mold, the blank is sufficiently cooled to retain its shape. To this end, the blank should remain in the blank mold for a sufficient time to allow the dissipation of a quantity of heat allowing the glass to reach the desired viscosity. It is easy to understand that this quantity of heat increases with the weight of the blank, which, at constant thermal conductivity, normally leads to an extension of the residence time in the blank mold. Added to this is the fact that, during the finishing stage, the molding surface of the mold will heat up via the heat transfer between the core of the blank and its surface.To avoid both the cooling time in the roughing mold becoming excessive and incompatible with an industrial production rate and the surface temperature of the finishing mold becoming excessive and leading to a modification of its structure, it is therefore advisable to carefully choose the mold material so that it has sufficient thermal conductivity.

[0012] For large objects such as sparkling wine and champagne bottles, molds made of copper and tin alloys, particularly bronze, have been proposed, which have good thermal conductivity. However, these molds are very expensive.

[0013] It is therefore desirable to have glass molds which, while exhibiting good thermal conductivity, are less expensive than molds made of copper and tin alloys.

[0014] Then, glassware molds have a geometric function since they give the article its final shape. This function is however undermined by problems of mold wear. These molds, most often made of cast iron, bronze (and other alloys including copper and tin), or steel (notably iron-carbon steels, stainless steels, refractory steels), tend to wear quickly, particularly in areas such as the joint plane (or seam), the bottom, the ring or even the neck of the mold, due to abrasion and / or corrosion due to the presence of silica in the glass. In order to avoid having to change the entire mold, techniques of recharging with a torch, Plasma Transferred Arc (PTA) or laser have been proposed, during which a layer of metal alloy is fused onto the surface of a mold, at the edges.The mold thus obtained is then machined after cooling in order to obtain the desired geometry.

[0015] However, known resurfacing techniques are not entirely satisfactory, as they only treat the edges and not the entire molding surface. Treating the entire molding surface with these known techniques carries a high risk of mold cracking. Therefore, known resurfacing techniques do not completely prevent mold wear, which means that molds must be replaced regularly.

[0016] It is therefore desirable to have new reloading techniques that can treat the entire casting surface.

[0017] One aim of the present application is to remedy at least in part the aforementioned drawbacks.

[0018] To this end, the invention relates, according to a first aspect, to a surface treatment method for treating a metal surface of a metal part configured to come into contact with a parison, for example a molding surface of a glassware mold, the surface treatment method comprising the following steps: cold projection of a metal powder in the solid state onto the metal surface so as to obtain a solid deposit; and machining the solid deposit so as to obtain a coating.

[0019] Some preferred but non-limiting features of the surface treatment method according to the first aspect are the following, taken individually or in combination:

[0020] - the metal powder is projected using a projection gas subjected to a pressure greater than thirty bars, for example between forty bars and seventy bars, for example around fifty bars;

[0021] - the metal powder is projected using a projection gas heated to a temperature greater than or equal to 750°C, in particular greater than or equal to 800°C, for example between 900°C and 1150°C;

[0022] - during the projection step, a projection distance, corresponding to a distance between a nozzle for projection of the metal powder and the metal surface, is between 15 millimeters and 60 millimeters, preferably between 15 and 35 millimeters, for example equal to approximately 20 millimeters or approximately 30 millimeters;

[0023] - during the projection step, a speed of movement of a nozzle for projection of the metal powder during projection is between 200 millimeters per second and 1000 millimeters per second, for example between 200 and 450 millimeters per second;

[0024] - the projection step is carried out for a sufficient time to obtain a solid deposit having a thickness of between 0.3 millimeters and 3 millimeters, preferably between 0.5 millimeters and 2.5 millimeters;

[0025] - an injection flow rate of the metal powder into the projection gas is between 1 and 10 cm 3 / min, preferably between 2 and 3 cm 3 / min, for example of the order of 2.5 cm 3 / min ;

[0026] - the coating has better mechanical resistance than the metal surface, in particular better resistance to abrasion;

[0027] - the coating has a thermal conductivity higher than that of the metal surface;

[0028] - the metal powder consists essentially of NiCr powder; and / or - the metal powder consists essentially of, by mass relative to the total mass of the powder:

[0029] • between 60 and 70%, preferably between 62 and 68%, of copper;

[0030] • between 7 and 17%, preferably between 10 and 15%, of nickel;

[0031] • between 5 and 15%, preferably between 8 and 12%, of aluminum;

[0032] • between 5 and 15%, preferably between 8 and 12%, of zinc, it being understood that the sum of the components is equal to 100%.

[0033] According to a second aspect, there is provided a metal part, for example a glassware mold, comprising: a metal surface configured to come into contact with a parison; and a coating covering all or part of the metal surface and comprising a metal alloy resulting from the cold projection of a metal powder onto the metal surface in accordance with a surface treatment method according to the first aspect.

[0034] Some preferred but non-limiting features of the metal part according to the second aspect are the following, taken individually or in combination:

[0035] - the metal surface comprises at least one of the following materials: graphite cast iron with a lamellar, vermicular or spheroidal micrographitic structure, a copper and tin-based alloy such as bronze, iron-carbon steel, refractory steel or stainless steel, brass;

[0036] - the metal powder is made up mainly of nickel and chromium;

[0037] - the coating is obtained by cold spraying of a metal powder essentially consisting of NiCr powder or of a metal powder essentially consisting of, by mass relative to the total mass of the powder:

[0038] • between 60 and 70%, preferably between 62 and 68%, of copper;

[0039] • between 7 and 17%, preferably between 10 and 15%, of nickel;

[0040] • between 5 and 15%, preferably between 8 and 12%, of aluminum; and

[0041] • between 5 and 15%, preferably between 8 and 12%, of zinc; it being understood that the sum of the components is equal to 100%;

[0042] - the part comprises a glassware mold, the metal surface corresponding to the molding surface of the glassware mold and comprising at least one of the following materials: graphite cast iron with a lamellar, vermicular or spheroidal micrographitic structure, iron-carbon steel, refractory steel or stainless steel. According to a third aspect, an installation is proposed comprising:

[0043] - a machine for surface treatment of a glassware mold comprising: a support configured to receive a metal part, for example a glassware mold, having a metal surface configured to come into contact with a parison; and a projection nozzle configured to cold project a metal powder in the solid state onto the metal surface so as to obtain a solid deposit, and a machining station configured to machine the solid deposit and obtain a coating.

[0044] DESCRIPTION OF FIGURES

[0045] Other characteristics, aims and advantages will emerge from the following description, which is purely illustrative and non-limiting and is given with reference to the appended drawings, in which: Figure 1 schematically illustrates an example of an installation for the metal surface treatment of a metal part according to an embodiment; Figure 2 is a flowchart illustrating steps of a method for surface treatment of a metal part according to an embodiment; and Figure 3 is a schematic sectional view of a glassware mold comprising a coating according to an embodiment.

[0046] Throughout the figures, similar elements have identical references.

[0047] DETAILED DESCRIPTION

[0048] In the following, the present disclosure will be more particularly described in the case of the surface treatment of the molding surface 2 of a glassware mold 1. This is not, however, limiting, the present disclosure applying to the surface treatment of any metal surface of a metal part configured to come into contact with the parison.

[0049] With reference to Figure 1, the present application relates to the surface treatment of all or part of the molding surface 2 of a glassware mold 1. The glassware mold 1 may in particular comprise a blank mold 1 configured to receive a drop of glass (parison) and form a blank. The molding surface 2 corresponds to the surface of the mold 1 likely to come into contact with the parison during the molding process. The molding surface 2 may in particular comprise at least one of the following materials: graphite cast iron with a lamellar, vermicular or spheroidal micrographitic structure, bronze (and other alloys comprising copper and tin), steel of the iron-carbon steel type, refractory steel or stainless steel, brass. Preferably, the glassware mold 1 is integrally formed from the same constituent material as the molding surface 2.In order to treat the molding surface 2 of a glassware mold 1, it is proposed to cold-project and at a very high speed, by a projection gas 3 under high pressure transporting it, a metal powder 4 onto all or part of the molding surface 2.

[0050] Cold and high-pressure projection, known by its English name "cold spray", makes it possible to obtain a deposit density very close to the theoretical density of the solid metallic material constituting the powder, without heating the molding surface 2 during deposition, which avoids modifying the metallurgical quality of the molding surface 2 and the solid deposit 5. It also makes it possible to obtain high thicknesses of deposits (up to several millimeters) with low roughness and a material yield of more than 90%, as well as high interparticle cohesion. In addition, the implementation of this cold projection does not require a prior step of preparing the molding surface 2 or masking the mold 1 to be treated.

[0051] SURFACE TREATMENT FACILITY 9

[0052] An installation 9 intended for this treatment of all or part of the molding surface 2 of a glassware mold 1 is shown in Figure 1. This installation 9 comprises a surface treatment machine 10 and a machining station 11.

[0053] The surface treatment machine 10 is configured to cold spray the metal powder 4, in solid form, onto the molding surface 2 of the mold 1. For this purpose, it comprises a spray nozzle 7, preferably made of ceramic, comprising:

[0054] - a system for heating and pressurizing a projection gas 3, typically nitrogen or helium, in a pressurization chamber 12;

[0055] - a powder dispenser 13 for supplying the metal powder 4;

[0056] - an injection system 18 for injecting the metal powder 4 into the projection gas 3 downstream of the pressurization chamber 12 so that it is not heated by the surface treatment machine 10 and therefore remains in the solid state;

[0057] - a transport system 19 for transporting the metal powder 4 from the powder distributor 13 to the injection system 18 by means of a carrier gas (typically identical to the projection gas 3);

[0058] - a convergent-divergent nozzle 8 placed downstream of the injection system 18 and configured to accelerate the projection gas 3 when it transports the metal powder 4, the divergent part of the nozzle 8 forming a deposition tube 14; and

[0059] - a cooling system 15 which may comprise a conduit which surrounds the deposition tube 14 in order to cool the projection gas 3, which transports the metal powder 4, by conduction by circulating a cooling fluid around the deposition tube 14; the cooling fluid may in particular comprise distilled water at a temperature lower than the temperature of the projection gas 3, typically at a temperature between 8 and 20°C.

[0060] The projection nozzle 7 has an outlet diameter (at the free end of the deposition tube 14) of between two and ten millimeters, for example of the order of six millimeters.

[0061] The surface treatment machine 10 further comprises a support 17 configured to fix the glassware mold 1 relative to the projection nozzle and actuators (not shown) configured to move the projection nozzle 7 relative to the molding surface 2 in the three spatial directions. These actuators can move the projection nozzle 7, the support 17 on which the mold 1 is mounted or both the projection nozzle 7 and the support 17. The actuators are configured to move the nozzle 7 relative to the molding surface 2 at a speed of between 200 millimeters per second (mm / s) and 1000 millimeters per second (mm / s). Preferably, in order to limit premature wear of the installation, and in particular of the injection head, the scanning speed is between 200 and 450 mm / s (to within 5%).The actuators are further configured to shift the impact zone by a distance between 0.5 millimeters and 2.5 millimeters (no sweep between two adjacent cords), for example in the order of one or two millimeters (to within 10%).

[0062] The heating system is configured to heat the projection gas 3 to a temperature greater than or equal to 750°C, in particular greater than or equal to 800°C, for example between 900°C and 1150°C. The projection gas 3 is furthermore pressurized in the pressurization chamber to a pressure greater than or equal to thirty-five bars, preferably between forty bars and seventy bars, for example of the order of fifty bars.

[0063] The projection nozzle 7 can be controlled by a remote control station 16, placed near the surface treatment machine 10 or remotely.

[0064] The machining station 11 comprises a support configured to receive the mold 1 coated with the solid deposit 5 and a machining tool, such as a milling machine, configured to machine the solid deposit 5 and obtain the coating 6. The machining tool can be handled by an operator or mounted on the installation 8 and controlled by a remote control station, for example the same control station 16 of the projection nozzle 7.

[0065] SURFACE TREATMENT PROCESS 100

[0066] A method 100 for treating the molding surface 2, implemented by the surface treatment installation 9, is shown in Figure 2. It comprises the following steps:

[0067] - cold projection 110 of a metal powder 4 in the solid state onto the molding surface 2 of the glassware mold 1 so as to obtain a solid deposit 5; and

[0068] - machining 120 of the solid deposit 5 so as to obtain a coating 6 (Figure 3).

[0069] The method 100 can be applied to the entire molding surface 2 of the mold 1 or to only a part of this surface 2.

[0070] During the projection step 110, a high-temperature (typically nitrogen or helium) and high-pressure projection gas 3 is used to propel the metal powder 4 at a supersonic speed (greater than 300 m / s) onto the molding surface 2 in order to create a solid deposit 5 intended to form the coating 6 by impact of the metal powder 4 on the molding surface 2, the impact force ensuring the quality of the deposit. In the present application, the deposit is said to be “solid” insofar as the grains of the metal powder 4 remain in the solid state throughout the projection and adhesion step 110 to the molding surface 2, as opposed to processes during which the temperature of the metal powder 4 exceeds its melting temperature so that all or part of the powder 4 melts at some point during the process.When the metal powder 4 comes into contact at high speed with the molding surface 2, it mechanically adheres to the molding surface 2 by plastic deformation with strong adhesion, which makes it possible to avoid defects linked to high temperatures such as oxidation, residual stresses, phase transformations, etc. The solid deposit 5 is then integral with the molding surface 2, that is to say that it can only be separated from the molding surface 2 by being completely or partially damaged.

[0071] The projection step 110 is said to be cold insofar as the metal powder 4 is not heated before or during deposition, other than by its contact with the projection gas 3 or the molding surface 2.

[0072] During the projection step 110, the projection gas 3 is heated and pressurized in order to ensure that the metal powder 4 is projected at a projection speed (speed of the metal powder 4 at the outlet of the nozzle 7) capable of allowing the plastic deformation of the metal powder 4 during its impact against the contact surface. It will be noted that the gas is heated and pressurized before injecting the solid powder into the gas and its projection onto the molding surface 2 in order to ensure that the metal powder 4 remains in the solid state. For this purpose, said projection speed is greater than or equal to the critical speed of the metal powder 4.This critical speed corresponds to the speed from which the attachment (adhesion) of the solid deposit 5 is possible: when the impact speed is lower than the critical speed of the material, then the particles of metal powder 4 do not deform plastically and can rebound and / or erode the molding surface 2. The critical speed depends on the nature of the material and the size of the grains of the metal powder 4. The critical speed is for example higher in the case of a metal powder 4 comprising a hard material, such as a titanium dioxide-based material (above 1250 m / s), than in the case of a metal powder 4 comprising a ductile material, such as a copper-based material (of the order of 600 m / s). An equation E1 for determining the critical speed of a material was demonstrated by T. Schmidt, F. Gartner, H. Assadi, H. Kreye, “Development of a generalized parameter window for cold spray deposition”, Acta Mater.54 (2006) 729-742 ; https: / / doi.Org / 10.1016 / j.actamat.2005.10.005) :. where: Or is the breaking stress of the material; p is the density of the material to be characterized;

[0073] Tj is the initial temperature of the material to be characterized;

[0074] T m is the melting temperature of the material to be characterized; c p is the specific heat;

[0075] T r is a reference temperature equal to 293 K; and

[0076] Fi and F2 are calibration coefficients used to recalibrate the calculated value to measured speed values.

[0077] The pressure applied to the projection gas 3 is therefore chosen so as to exceed the critical speed of the metal powder 4 used for the solid deposition 5. A pressure greater than or equal to thirty-five bars, preferably greater than or equal to forty bars, for example equal to fifty bars, is suitable for most metal powders which can be used in the surface treatment of a glassware mold.

[0078] Furthermore, the temperature to which the projection gas 3 is heated is typically greater than or equal to 750°C, in particular greater than or equal to 800°C, for example between 900°C and 1150°C. This heating temperature is advantageously at least 300°C below the melting temperature of the constituent of the metal powder 4 with the lowest melting temperature and for example between 300 and 700°C below this melting temperature.

[0079] If necessary, the projection gas 3 can further be accelerated by the configuration of the projection nozzle 7 (modification of the gas passage section, for example in a convergent-divergent nozzle 8, etc.).

[0080] For a nickel-chromium powder as described below, the critical speed is, for example, of the order of 574 m / s.

[0081] If necessary, the projection gas 3 can be cooled downstream of the injection point of the metal powder 4 into the gas in order to ensure that the metal powder 4 remains solid without reducing the projection speed of the powder. The projection step 110 is carried out so as to obtain a solid deposit 5 whose thickness is sufficient to allow machining of the solid deposit 5 and obtaining of the coating 6. This thickness of the solid deposit 5 is typically between 0.3 millimeters and 3 millimeters, preferably between 0.5 millimeters and 2.5 millimeters. The thickness of the coating 6 (after machining) can thus be between 0.1 millimeters and 1.5 millimeters.

[0082] For this purpose, the molding surface 2 is moved relative to the surface treatment machine 10 during the projection step 110 in order to carry out a deposit on all or part of the molding surface 2. The projection nozzle 7 can be moved while the glassware mold 1 is fixed, or alternatively the glassware mold 1 can be moved while the projection nozzle 7 is fixed, or both the projection nozzle 7 and the glassware mold 1 are moved. The relative movement speed and the number of passes over a given surface determine the thickness of the deposit. For example, the relative displacement speed of the projection nozzle 7 and the molding surface 2 of the glassware mold 1 may be between 200 millimeters per second (mm / s) and 1000 millimeters per second (mm / s), for example of the order of 200 millimeters per second (mm / s) to 450 millimeters per second (mm / s) (to within 5%).

[0083] The flow rate of supply of the metal powder 4 by the distributor 13 is between 1 and 10 cm 3 / min, preferably between 2 and 3 cm 3 / min, for example of the order of 2.5 cm 3 / min. The metal powder 4 thus supplied is entirely transported by the carrier gas to the injection system 18, so that this supply flow rate also constitutes an injection flow rate of the metal powder 4 into the projection gas 3 by the injection system 18. For this purpose, the flow rate of carrier gas is typically between 2.0 and 6.0 cubic meters per hour (m 3 / h), for example of the order of 4.0 or 4.5 cubic meters per hour (m 3 / h).

[0084] The size (width of the bead) of the solid deposit 5 is preferably between 0.5 millimeters and two millimeters, for example of the order of one millimeter (to within 10%). This size depends on the distance between the outlet of the projection nozzle 7 of the surface treatment machine 10 and the molding surface 2 and on the outlet diameter of the projection nozzle 7. In order to obtain the aforementioned solid deposit size, said distance is typically between fifteen millimeters and sixty millimeters, preferably between fifteen millimeters and thirty-five millimeters, for example equal to approximately twenty millimeters or approximately thirty millimeters, for an outlet diameter of the projection nozzle 7 of between two and ten millimeters, for example of the order of six millimeters.

[0085] The scanning pitch (distance between the centers of two adjacent solid deposit beads 5) is between 0.5 millimeters and two millimeters, for example of the order of one millimeter (to within 10%). It is preferably substantially equal to the size of the solid deposit 5. METAL POWDER 4

[0086] The metal powder 4 preferably comprises 75% by mass or more, advantageously at least 80% by mass, of spherical grains, relative to the total mass of the powder.

[0087] Laser particle size is measured according to ISO 13320:2019.

[0088] The diameter of the grains of the powder is advantageously between 10 and 50 pm, in particular between 12 and 45 pm, and preferably has a D50 value between 20 and 30 pm.

[0089] The melting temperature of the powder components is typically higher than the parison temperature - which can reach 1100°C - in order to avoid thermal degradation of the coating 6 during molding. Preferably, the melting temperature of the powder component having the lowest melting temperature is 300°C higher than the parison temperature.

[0090] The "packed density" is evaluated according to the basis of the NF EN ISO 3923 (2018) standard relating to "Metal powders - Determination of the apparent density after packing". Typically, a test tube with a volume of 25 cm is used. 3 and a KERN SEAL balance with a maximum capacity of 6000 g and a resolution of 0.1 g. The compaction is stopped after 3000 strokes.

[0091] The "yray density" is evaluated according to the basis of the standard NF EN ISO 8130-2 (2011) relating to "Powders for coating - Determination of the density using a gas pycnometer (reference method)". A helium pycnometer (Quantachrome Upyc 1200 e) with a 10 cm cell is used. 3 The mass of the powder is measured with a balance, for example METTLER TOLEDO AB104 with a maximum capacity of 110 g and a resolution of 0.1 mg.

[0092] The tapped density of metal powder is typically between 3 and 7 g / cm 3 .

[0093] True density is typically between 6 and 10 g / cm 3 , preferably with a low standard deviation, for example 0.001. Metal powders having such a true density in fact make it possible to obtain a denser solid deposit 5.

[0094] For the purposes of this disclosure, a powder is “essentially composed” of a compound A when the powder comprises at least 98% by mass, preferably at least 99% by mass of the compound A, relative to the total mass of the powder.

[0095] Metal powder comprising a NiCr alloy

[0096] According to a first embodiment, the metal powder 4 is essentially composed of an alloy of nickel and chromium (called a nickel-chromium alloy and denoted NiCr). By essentially composed, it will be understood here that at least 98% by mass of the NiCr powder is composed of the alloy of nickel and chromium, the remainder being able to comprise at most 2% by mass of another component. Preferably, the matrix powder comprises at least 99% by mass of NiCr. The other component may for example comprise at least one of the following elements: carbon, silicon, manganera, oxygen, nitrogen. This makes it possible to obtain a coating 6 comprising NiCr which gives the mold 1 thermomechanical protection. In particular, a coating 6 comprising NiCr gives the mold 1 better abrasion resistance, which is particularly useful in the case of molds for borosilicate glasses and in the case of molds made of copper and tin alloy.Indeed, borosilicate glasses are particularly abrasive and generally lead to premature wear of the molds. As for molds made of copper and tin alloy, they have good thermal conductivity and are generally very expensive, so it is advantageous to lose some of the thermal conductivity of the mold if it allows it to be preserved longer.

[0097] Thus, according to an advantageous variant of this first embodiment, the glassware mold 1 is a mold for borosilicate glass or a mold made of a copper and tin alloy, for example bronze.

[0098] The nickel content in the NiCr alloy is advantageously between 40% and 85% by mass, preferably between 45 and 80% by mass, relative to the total mass of the NiCr alloy, the remainder being essentially made up of chromium.

[0099] According to a first variant, the nickel content in the NiCr alloy is between 40 and 50% by mass, while the chromium content is between 50% and 60% by mass, relative to the total mass of the NiCr alloy (i.e. the complement necessary to reach essentially 100% of the mass of NiCr alloy). For example, the nickel content in the NiCr alloy is substantially equal to 50% by mass, the chromium content also being substantially equal to 50% by mass, relative to the total mass of the NiCr alloy (i.e. the complement necessary to reach essentially 100% of the mass of NiCr alloy). According to a second variant, the nickel content in the NiCr alloy is about 80% by mass, while the chromium content is about 20% by mass, relative to the total mass of the NiCr alloy (i.e. the complement necessary to reach essentially 100% of the NiCr alloy mass).

[0100] The particle size of the NiCr powder is advantageously between 10 and 50 pm. The D50 value of the NiCr powder is typically between 20 and 30 pm, preferably between 25 and 27 pm, for example substantially equal to 26.1 pm. The D10 value of the NiCr powder is typically between 10 and 20 pm, preferably between 14 and 16 pm, for example substantially equal to 14.7 pm. The D90 value of the NiCr powder is typically between 40 and 50 pm, preferably between 43 and 45 pm, for example substantially equal to 44.0 pm. The tapped density of the NiCr powder is typically between 4 and 5 g / cm 3 , notably between 4.3 and 4.8 g / cm 3 , for example of the order of 4.7 g / cm 3 The true density of NiCr powder is typically between 7.5 and 8.5 g / cm 3 , notably between 7.6 and 8.0 g / cm 3 , for example of the order of 7.71 g / cm 3 .

[0101] Metal powder comprising a cupronickel type alloy

[0102] According to a second embodiment, the metal powder 4 comprises or is essentially made up of an alloy of copper, nickel, aluminum and zinc, which for the sake of simplification will be called “cupronickel” in the following or CuNiAIZn. This makes it possible to obtain a coating 6 comprising a so-called “cupronickel” alloy which gives the mold better thermal conductivity, which makes it possible to cool the glass more homogeneously during contact with the coated mold. Such a coating is particularly advantageous in the case of molds for soda-lime glasses.

[0103] Thus, according to an advantageous variant of this first embodiment, the glassware mold 1 is a mold for soda-lime glasses. The material of the mold 1 is typically a cast iron, for example a graphite cast iron with a lamellar, vermicular or spheroidal micrographitic structure, an iron-carbon steel, a refractory steel or a stainless steel.

[0104] According to this second embodiment, the metal powder 4 is essentially made up of a powder of an alloy comprising, by mass relative to the total mass of the alloy:

[0105] • between 60 and 70%, preferably between 62 and 68%, of copper;

[0106] • between 7 and 17%, preferably between 10 and 15%, of nickel;

[0107] • between 5 and 15%, preferably between 8 and 12%, of aluminum;

[0108] • between 5 and 15%, preferably between 8 and 12%, of zinc; and

[0109] • the possible complement preferably being essentially made up of chromium, manganese and / or iron; it being understood that the sum of the components is equal to 100%.

[0110] By essentially consisting, it will be understood here that the matrix powder comprises at least 97%, preferably at least 99%, of copper, nickel, aluminum and zinc. Typically, the other component represents at most 3% by mass, preferably at most 1% by mass, relative to the total mass of the alloy. Preferably, the other component may comprise, by mass relative to the total mass of the alloy:

[0111] • at most 1% chromium;

[0112] • at most 1% manganese; and / or

[0113] • at most 1% iron. By way of non-limiting example, the “cupronickel” matrix powder may comprise (relative to the total mass of the matrix powder):

[0114] • 68.1% by mass (± 0.4%) of copper;

[0115] • 15.4% by mass (± 0.1%) of nickel;

[0116] • 9.02% by mass (± 0.06%) of aluminum;

[0117] • 7.5% by mass (± 0.1%) of zinc; And

[0118] • 640 ppm (m) of oxygen; provided that the sum of the components is equal to 100%.

[0119] The tapped density of cupronickel powder is typically between 1 and 6 g / cm 3 , notably between 4.5 and 5.5 g / cm 3 The true density of cupronickel powder is typically between 4 and 9 g / cm 3 , especially between 7.5 and 9.0 g / cm 3 .

[0120] The particle size of the “cupronickel” powder is advantageously between 15 and 45 pm. The D50 value of the “cupronickel” powder is typically between 20 and 30 pm.

[0121] BENEFITS

[0122] Thus, thanks to the invention described above, it is possible to improve both the abrasion resistance and the thermal conductivity of the glassware mold 1. It is therefore possible to reduce the frequency of replacement of the glassware molds, by completely coating their molding surface with a coating having good abrasion resistance, such as a NiCr coating, or to use for the molding of large volumes of glass or soda-lime glasses less expensive molds whose molding surface is simply coated with a coating having good thermal conductivity, such as a “cupronickel” alloy coating.

[0123] This can reduce the cost of purchasing and replacing molds.

[0124] EXAMPLES OF THE TREATMENT OF THE METAL SURFACE OF A METAL PART 1

[0125] Examples of carrying out the treatment of the metal surface of a metal part will now be described.

[0126] EXAMPLE 1

[0127] Preparation of metal powder 4

[0128] The metal powder 4 is obtained by mixing a matrix powder of NiCr with a lubricating powder of TiO2, in the following proportions: - 95% by mass of NiCr powder comprising 50% by mass of nickel and 50% by mass of chromium (i.e., in the total powder, 47.5% by mass of nickel and 47.5% by mass of chromium); and

[0129] - 5% by mass of titanium dioxide powder.

[0130] These powders are mixed for 17.5 hours to obtain a homogeneous metal 4 powder, which is placed in an airtight container until use.

[0131] The NiCr powder used consists of an alloy comprising approximately 50% by mass of Nickel and approximately 50% by mass of Chromium. It is marketed by SANDVIK OSPREY.

[0132] The melting temperature of the NiCr compound is 1345 °C.

[0133] The NiCr powder comprises at least 75% by mass, advantageously at least 80% by mass of spherical grains, relative to the total weight of the NiCr powder.

[0134] The average value of the packed density after three measurements is 4.7 g / cm 3 .

[0135] The powder test sample for true density measurement was 30.8561 g. The average true density value after five measurements was 7.71 g / cm 3 with a standard deviation of 0.001.

[0136] Three measurements were carried out to determine the parameters D10, D50 and D90 (laser granulometry). The average of these parameters is as follows:

[0137] - D10 = 14.7 pm;

[0138] - D50 = 26.1 pm; and

[0139] - D90 = 44.0 pm.

[0140] The TiC>2 powder used is marketed by Saint Gobain under the name “TiC>2 anastase nanostructured powder”.

[0141] The TiC>2 powder comprises at least 95% by mass, advantageously at least 98% by mass of spherical grains, relative to the total weight of the TiC>2 powder. The surface appearance of the grains is very smooth. At least 80% by weight of the grains have internal porosities, relative to the total weight of the TiC>2 powder.

[0142] The average value of the packed density after three measurements is 1.2 g / cm 3 .

[0143] The true density was measured under the same conditions as for the NiCr compound, with a powder sample of 7.3359 g. The average true density value after five measurements was 4.16 g / cm 3 with a standard deviation of 0.002.

[0144] The laser granulometry was carried out under the same conditions as for the NiCr compound: the average of these parameters is as follows:

[0145] - D10 = 8.80 pm;

[0146] - D50 = 17.8 pm; and

[0147] - D90 = 33.9 pm. Preparation of plates representative of the metal surface of a metal part

[0148] Five flat plates are prepared. Each plate has a free surface representative of the metal surface of the metal part, for example the molding surface 2 of a glass mold 1, intended to receive a drop of glass.

[0149] The five plates 22 are made of graphite cast iron with a lamellar micrographitic structure of the same composition.

[0150] Each plate has its free surface covered with a coating obtained according to the method 100 of the present disclosure. Each plate 22 has its free surface 21 covered with a lubricating coating 6 obtained according to the method 100 of the present disclosure, with the following parameters:

[0151] Pressure Temperature ace of Speed

[0152] P of gas of gas of of

[0153] Plate sweep projection projection projection sweep (mm) ' 1 )

[0154] For each of these plates, the following parameters were used: Laval type 7 ceramic projection nozzle (convergent divergent) with an outlet diameter of 6 mm; powder flow rate: 2.89 cm 3 / min; projection gas 3: nitrogen; projection gas flow rate: 4 m 3 / h; cooling fluid: distilled water; metal powder 4: consisting of nickel-chromium and titanium dioxide, as described above in example 1, at room temperature (20°C); and number of passes: 10

[0155] The effectiveness of the cold spray parameters can be evaluated in particular by measuring the thickness of the deposits obtained:

[0156] Thickness j Deposition plate j (mm) 0.84 0.60 0159 0.72 1.02 Plate 5 has an optimal thickness. The deposition efficiency of plate 1 is also satisfactory.

[0157] The porosity of the coatings was assessed by making a slice of the coating.

[0158] Comparison of plates 3 and 4 shows equivalent efficiency and similar porosity by increasing the pressure and temperature parameters (40 bar - 900°C to 50 bar - 1000°C). Plate 3 was made with a scanning pitch of 2 mm and a speed of 200 mm / s while the coating of plate 1 was made with a pitch of 1 mm and a speed of 400 mm / s. As a result, reducing the pitch and increasing the projection speed allows to increase the deposited thickness and to decrease the porosity (evaluated by image analysis at 1.0% ± 0.5 for plate 1 against 2.3% ± 0.3 for plate 3).

[0159] The comparison of plates 1 and 5 demonstrates a gain in efficiency (ratio between the mass of the coating obtained and the mass of powder projected onto the plate) by increasing the temperature of the projection gas from 1000°C (plate 1) to 1100°C (plate 2). The efficiency (%DE, acronym for deposition efficiency) of plates 1 and 5 is 52% and 68% respectively.

[0160] The projection distance is optimized at 20 mm because we observe a slight reduction in the thickness deposited on plates 3 and 2 (20 mm and 35 mm).

[0161] Plate 5 leads to the thickest coating and above all a very good compactness of the coating which displays very little porosities. The quantification of the porosity rate by image analysis evaluates the porosity rate of the coating of plate 5 at 0.3% ± 0.05 and that of plate 3 at 2.3 ± 0.3.

[0162] The following table gives the porosity size indices (equivalent diameters in area) of the coatings of plates 3 and 5 calculated by image analysis. The minimum size of the porosities considered is 0.99 pm 2 .

[0163] D(A)io D(A)50 D(A)90

[0164] Plate (pm) (pm) (pm)

[0165] The median size (equivalent in area) of the porosity is three times smaller in the coating of plate 5 than in the coating of plate 3. Note that these porosity size values ​​are satisfactory for application to glassware molds.

[0166] The binding rate of the coating of plate 3 is evaluated by image analysis at 83.7% and that of plate 5 at 98.4% demonstrating the excellent performance of the parameterization of plate 5.

[0167] No cracks were found in all plates and cross-sections analyzed. The coating of plate 5 is optimal in terms of thickness, porosity, yield and bonding rate. The roughness of coating 5 is 7.0 pm (measured with a Mitutoty SJ210 roughness tester).

[0168] For NiCr powder, the optimized projection parameters are as follows:

[0169] EXAMPLE 2

[0170] Preparation of metal powder 4

[0171] Metal powder 4 is obtained by mixing a matrix powder of NiCr with a lubricating powder of TiC>2, in the following proportions:

[0172] - 95% by mass of NiCr powder comprising 78.7% by mass of nickel (± 0.6%) and 20.10% by mass of chromium (± 0.05%) (i.e., in the total powder, 39.35% by mass of nickel and 10.1% by mass of chromium); and

[0173] - 5% by mass of titanium dioxide powder.

[0174] The NiCr powder used is Metco 43VF-NS powder marketed by SANDVIK OSPREY.

[0175] The exact composition of the powder is listed below:

[0176] These powders are mixed for 17.5 hours to obtain a homogeneous metal powder 4, which is placed in an airtight container until use. The melting temperature of the NiCr compound is 1345 °C.

[0177] NiCr powder comprises irregularly shaped particles.

[0178] The average value of the packed density after three measurements is 4.6 g / cm 3 .

[0179] The average true density value after five measurements was 8.30 g / cm 3 .

[0180] Three measurements were carried out to determine the parameters D10, D50 and D90 (laser granulometry). The average of these parameters is as follows:

[0181] - D10 = 11.7 pm;

[0182] - D50 = 21.6 pm; and

[0183] - D90 = 36.6 pm.

[0184] The TiC>2 powder is identical to that used in example 1.

[0185] Preparation of plates representative of the molding surface of a glassware mold

[0186] Seven 22-plane plates are prepared identically to Example 1, using NiCr 80 / 20 powder.

[0187] The seven plates 22 are made of graphite cast iron with a lamellar micrographitic structure of the same composition.

[0188] Each plate 22 has its free surface 21 covered with a lubricating coating 6 obtained according to the method 100 of the present disclosure, with the following parameters: Distance Pressure Temperature Speed

[0189] No of gas of gas of of

[0190] Plate scanning projection projection projection scanning (mm)

[0191] _ ' 1 )

[0192] For each of these plates, the following parameters were used: Laval type 7 ceramic projection nozzle (convergent divergent) with an outlet diameter of 6 mm; powder flow rate: 2.45 cm 3 / min; projection gas 3: nitrogen; projection gas flow rate: 4 m 3 / h; cooling fluid: distilled water; metal powder 4: consisting of nickel-chromium and titanium dioxide, as described above in example 2, at room temperature (20°C); and number of passes: 10 The effectiveness of the cold spray parameters is evaluated by measuring the thicknesses of the deposits obtained:

[0193] Thickness of the deposit plate (mm)

[0194] The coating of plates 1, 5 and 7 has an optimal thickness. The coatings were obtained with a pitch of 1 mm and a speed of 400 mm / s. This pair of projection pitch and scanning speed parameters are therefore relevant.

[0195] Analysis of plate coatings 1, 2, 3, 4 and 7 shows that it is advantageous to use lower pressure / temperature parameters for spraying NiCr 80 / 20 powder.

[0196] The yield obtained is satisfactory for all plates (88% for plate 5 and 65% for plate 2 for example). The yield of plate 1 is calculated at 80%.

[0197] The porosity of the coatings was assessed by taking a slice of the coating. The coatings have very good metallurgical quality, with a porosity rate between 1.5% and 4%.

[0198] The porosity of the coatings was assessed by taking a slice of the coating. The coatings of plates 1 to 6 have very good metallurgical quality, with a porosity rate between 1.5% and 3%.

[0199] The bonding rate of the coatings is higher than 95% for each plate. The coating of plate 7 has a lower bonding rate and a higher porosity rate which translate into a lower metallurgical quality: this is due to the low temperature and pressure values ​​of the projection gas (800 °C and 40 bar).

[0200] The following table gives the porosity size indices (equivalent diameters in area) of the coatings of plates 1 and 7 calculated by image analysis. The minimum size of the porosities considered is 0.99 pm 2 .

[0201] Plate

[0202] M EU

[0203] No cracks were found in all plates and cross-sections analyzed. The coating of plate 1 is optimal in terms of thickness, porosity, yield and bonding rate. The roughness of coating 1 is equal to 6.5 pm (measured with a Mitutoty SJ210 roughness tester).

[0204] EXAMPLE 3

[0205] Preparation of metal powder 4

[0206] Metal powder 4 is obtained by mixing a cupronickel type matrix powder with a TiC>2 lubricating powder, in the following proportions:

[0207] - 95% by mass of Cupronickel powder; and

[0208] - 5% by mass of titanium dioxide powder.

[0209] The Cupronickel powder used is marketed by NANOVAL. The exact composition of the powder is listed below:

[0210] These powders are mixed for 17.5 hours to obtain a homogeneous metal 4 powder, which is placed in an airtight container until use.

[0211] The melting temperature of the powder is 1235°C.

[0212] Cupronickel powder consists of spherical particles, except for a few clusters that are very irregular. The grains do not have many satellites.

[0213] The average value of the packed density after three measurements is 4.6 g / cm 3 .

[0214] The average true density value after five measurements was 7.44 g / cm 3 .

[0215] Three measurements were carried out to determine the parameters D10, D50 and D90 (laser granulometry). The average of these parameters is as follows:

[0216] - D10 = 14.8 pm;

[0217] - D50 = 24.4 pm; and

[0218] - D90 = 40.0 pm.

[0219] The TiC>2 powder is identical to that used in example 1.

[0220] Preparation of plates representative of the molding surface of a glassware mold

[0221] Eight 22-plane plates are prepared identically to Example 1, using NiCr 80 / 20 powder.

[0222] The eight plates 22 are made of graphite cast iron with a lamellar micrographitic structure of the same composition.

[0223] Each plate 22 has its free surface 21 covered with a lubricating coating 6 obtained according to the method 100 of the present disclosure, with the following parameters:

[0224] For each of these plates, the following parameters were used: Laval type 7 ceramic projection nozzle (convergent divergent) with an outlet diameter of 6 mm; powder flow rate: 2.5 cm 3 / min; projection gas 3: nitrogen; projection gas flow rate: 4 m 3 / h; cooling fluid: distilled water; metal powder 4: consisting of cupronickel and titanium dioxide, as described above in example 3, at room temperature (20°C); and number of passes: 10

[0225] The effectiveness of the cold spray parameters is evaluated by measuring the thickness of the deposits obtained:

[0226] Thickness j Deposition plate

[0227] The coating of plates 1 to 3 is too thin, which shows that the temperature of the projection gas must be at least 800 °C. The efficiency gain is also very significant when the projection temperature increases from 800 °C to 900 °C. The efficiency is then stable for projection temperatures greater than or equal to 900 °C. The porosity of the coatings was evaluated by making a slice of the coating. The coatings have a very good metallurgical quality, with a porosity rate between 0.3% and 2%. The porosity rate of the coating of plate 7 is for example 0.3%, that of plates 5 and 8 1.4% and 1.0% respectively.

[0228] The porosity of the coatings was assessed by taking a slice of the coating. The coatings of plates 1 to 6 have very good metallurgical quality, with a porosity rate between 1.5% and 3%.

[0229] The following table gives the porosity size indices (equivalent diameters in area) of the coatings of plates 1 and 7 calculated by image analysis. The minimum size of the porosities considered is 0.99 pm 2 .

[0230] Pla

[0231] The binding rate of plates 5 and 7 is 72% and 88% respectively, which is very good.

[0232] No cracks were found in all plates and cross-sections analyzed.

[0233] The coating of plate 7 is optimal in terms of thickness, porosity, yield and bonding rate. The roughness of coating 7 is equal to 7.6 pm (measured with a Mitutoty SJ210 roughness meter).

[0234] For cupronickel powder, the optimized projection parameters are as follows:

Claims

CLAIMS 1. Surface treatment method (100) for treating a metal surface of a metal part configured to come into contact with a parison, for example a molding surface (2) of a glassware mold (1), the surface treatment method (100) comprising the following steps: cold projection (110) of a metal powder (4) in the solid state onto the metal surface so as to obtain a solid deposit (5); and machining (120) of the solid deposit (5) so as to obtain a coating (6).

2. Surface treatment method (100) according to claim 1, in which the metal powder (4) is projected using a projection gas (3) subjected to a pressure greater than thirty bars, for example between forty bars and seventy bars, for example approximately fifty bars.

3. Surface treatment method (100) according to one of claims 1 or 2, in which the metal powder (4) is projected using a projection gas (3) heated to a temperature greater than or equal to 750°C, in particular greater than or equal to 800°C, for example between 900°C and 1150°C.

4. Surface treatment method (100) according to one of claims 1 to 3, wherein during the projection step (110), a projection distance, corresponding to a distance between a projection nozzle (7) of the metal powder (4) and the metal surface (2), is between 15 millimeters and 60 millimeters, preferably between 15 and 35 millimeters, for example equal to approximately 20 millimeters or approximately 30 millimeters.

5. Surface treatment method (100) according to one of claims 1 to 4, wherein during the projection step (110), a speed of movement of a projection nozzle (7) of the metal powder (4) during the projection is between 200 millimeters per second (mm / s) and 1000 millimeters per second (mm / s), for example between 200 and 450 millimeters per second (mm / s).

6. Surface treatment method (100) according to one of claims 1 to 5, in which the projection step (110) is carried out for a sufficient time to obtain a solid deposit (5) having a thickness of between 0.3 millimeters and 3 millimeters, preferably between 0.5 millimeters and 2.5 millimeters.

7. Surface treatment method (100) according to one of claims 1 to 6, in which an injection flow rate of the metal powder (4) into the projection gas (3) is between 1 and 10 cm 3 / min, preferably between 2 and 3 cm3 / min, for example of the order of 2.5 cm 3 / min.

8. Surface treatment method (100) according to one of claims 1 to 7, wherein the coating (6) has better abrasion resistance than the metal surface (2).

9. Surface treatment method (100) according to one of claims 1 to 7, in which the coating (6) has a thermal conductivity greater than that of the metal surface (2).

10. Surface treatment method (100) according to one of claims 1 to 9, in which the metal powder (4) consists essentially of NiCr powder.

11. Surface treatment method (100) according to one of claims 1 to 9, in which the metal powder (4) consists essentially of, by mass relative to the total mass of the powder: • between 60 and 70%, preferably between 62 and 68%, of copper; • between 7 and 17%, preferably between 10 and 15%, of nickel; • between 5 and 15%, preferably between 8 and 12%, of aluminum; and • between 5 and 15%, preferably between 8 and 12%, of zinc; it being understood that the sum of the components is equal to 100%.

12. Metal part (1), for example a glassware mold, comprising: a metal surface (2) configured to come into contact with a parison; and a coating (6) covering all or part of the metal surface (2) and comprising a metal alloy resulting from the cold projection of a metal powder (4) onto the metal surface (2) in accordance with a surface treatment method (100) according to one of claims 1 to 9.

13. Metal part (1) according to claim 12, in which the metal surface (2) comprises at least one of the following materials: graphite cast iron with a lamellar, vermicular or spheroidal micrographitic structure, an alloy based on copper and tin Such as bronze, iron-carbon steel, refractory steel or stainless steel, brass.

14. Metal part (1) according to one of claims 12 and 13, in which the metal powder (4) consists essentially of nickel and chromium.

15. Metal part (1) according to one of claims 12 and 13, in which the coating (6) is obtained by cold spraying of a metal powder consisting essentially of NiCr powder or of a metal powder consisting essentially of, by mass relative to the total mass of the powder: • between 60 and 70%, preferably between 62 and 68%, of copper; • between 7 and 17%, preferably between 10 and 15%, of nickel; • between 5 and 15%, preferably between 8 and 12%, of aluminum; and • between 5 and 15%, preferably between 8 and 12%, of zinc, it being understood that the sum of the components is equal to 100%.

16. A metal part according to claim 15, said metal part comprising a glassware mold, the metal surface corresponding to the molding surface of the glassware mold and comprising at least one of the following materials: graphite cast iron with lamellar, vermicular or spheroidal micrographitic structure, iron-carbon steel, refractory steel or stainless steel.

17. Installation including: - a surface treatment machine (10) for a metal part, for example a glassware mold (1), comprising: a support (17) configured to receive a metal part (1) having a metal surface (2) configured to come into contact with a parison; and a projection nozzle (7) configured to cold-project a metal powder (4) in the solid state on the metal surface (2) so as to obtain a solid deposit (5), and - a machining station (11) configured to machine the solid deposit (5) and obtain a coating (6).

Images