Sink roller shaft sleeve for hot dipping and preparation method of sink roller shaft sleeve

Abstract

The invention relates to the technical field of shaft sleeve production, in particular to a sink roller shaft sleeve for hot dipping and a preparation method thereof. The shaft sleeve comprises a shaft sleeve base body, and a transition layer and a gradient layer are sequentially arranged outwards from the surface of the shaft sleeve base body; the transition layer is made of alloy powder, and the gradient layer is made of composite powder of alloy powder and laminated ceramic powder; when the transition layer raw material alloy powder is nickel alloy powder, the alloy powder in the gradient layer raw material is nickel alloy, and the laminated ceramic powder is ceramic powder plated with a nickel film on the surface; when the transition layer raw material alloy powder is cobalt alloy powder, the alloy powder in the gradient layer raw material is cobalt alloy, and the laminated ceramic powder is ceramic powder plated with a cobalt film on the surface; the percentage content of the alloy powder in the gradient layer is reduced in a stepped mode from inside to outside, and the percentage content of the film-coated ceramic powder in the gradient layer is increased in a stepped mode from inside to outside. The wear resistance and high temperature resistance of the sink roller shaft sleeve are improved, and the service life of the shaft sleeve is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of shaft sleeve production, and in particular to a sinking roller shaft sleeve for hot dip plating and a preparation method thereof. Background Art

[0002] The hot-dip galvanizing sinking roller is the core equipment of the continuous hot-dip galvanizing production line for strip steel. The sinking roller works in molten metals such as zinc, aluminum silicon, zinc aluminum magnesium, etc. at 450~500℃, and rotates with the strip steel under the support of the support arm. The shaft end of the sinking roller is subjected to high temperature and friction, so a replaceable metal sleeve is welded on the shaft end of the sinking roller, and a ceramic bearing is installed in the mounting hole of the sinking roller support arm to withstand high temperature friction movement.

[0003] Due to the large difference in hardness between metal sleeves and ceramic bearings and the fact that they work under high temperature conditions, wear and even surface peeling will occur in a short period of time. The service life of a set of sunken roller sleeves is only 5 to 25 days, affecting production stability and costs.

[0004] Patent CN 108018511A discloses a sunken roller sleeve and a preparation method thereof, which manufactures a wear-resistant layer by surfacing a Co alloy layer on the surface of a steel sleeve. However, the hardness of the Co alloy is still lower than that of the ceramic bearing, and the wear-resistant effect is limited.

[0005] Patent CN 203683643U discloses a hot-dip galvanizing device part, in particular, a sunken roller sleeve, including an axially hollow sunken roller sleeve body, the inner and outer surfaces of which are welded with a corrosion-resistant hardened layer with WC or / and MoB as a hard phase. Although this patent can improve the surface wear resistance of the sleeve, due to the direct cladding of metal ceramics on the surface of the steel sleeve, the thermal expansion coefficient is greatly different, and the cladding process is prone to defects such as pores, which makes it easy to fail under high temperature conditions.

[0006] Patent CN 110923608A discloses a method for preparing a wear-resistant coating for a sunken roller sleeve, which is prepared by spraying and sintering Fe-TiC mixed powder on the surface of a steel sleeve. This method uses an Fe-based metal ceramic coating, which does not have the heat resistance of Ni and Co-based coatings and is prone to failure under the working conditions of the sunken roller. Summary of the invention

[0007] In view of the technical problem that during the hot dip plating process, a sink roller sleeve is prone to failure due to low wear resistance and high temperature resistance, the present invention provides a sink roller sleeve for hot dip plating and a preparation method thereof, which improves the wear resistance and high temperature resistance of the sink roller sleeve and prolongs the service life of the sleeve.

[0008] In a first aspect, the present invention provides a sunken roller sleeve for hot dip plating, comprising a sleeve base body, and having a transition layer and a gradient layer in sequence from the surface of the sleeve base body outward; The raw material of the transition layer is alloy powder, and the raw material of the gradient layer is composite powder of alloy powder and coated ceramic powder; When the alloy powder of the transition layer raw material is nickel alloy powder, the alloy powder in the gradient layer raw material is nickel alloy, and the coated ceramic powder is ceramic powder with a nickel film coated on the surface; When the alloy powder of the transition layer raw material is cobalt alloy powder, the alloy powder in the gradient layer raw material is cobalt alloy, and the coated ceramic powder is ceramic powder with a cobalt film coated on the surface; The percentage of the alloy powder in the gradient layer decreases in a step-like manner from the inside to the outside, and the percentage of the coated ceramic powder in the gradient layer increases in a step-like manner from the inside to the outside.

[0009] Furthermore, the ceramic powder in the coated ceramic powder is at least one of Al2O3, ZrO2, TiO2, SiO2, WC, SiC or BN powder. The above ceramic material has a similar hardness to the ceramic bearing material corresponding to the sleeve, which reduces mutual wear.

[0010] Furthermore, the gradient layer includes the first layer to the fifth layer with equal thickness from the inside to the outside, and the mass ratios of the alloy powder to the coated ceramic powder in the first layer to the fifth layer are 9:1, 8:2, 7:3, 6:4, and 5:5, respectively.

[0011] In a second aspect, the present invention provides a method for preparing a sunken roller sleeve for hot dip plating, comprising the following steps: (1) A layer of alloy powder is sprayed on the surface of the sleeve substrate by direct spraying to form a transition layer; (2) spraying a plurality of layers of composite powder of alloy powder and coated ceramic powder on the surface of the transition layer by layer-by-layer spraying, wherein the percentage of alloy powder decreases and the percentage of coated ceramic powder increases with each layer, and a gradient layer is formed after the layer-by-layer spraying is completed to obtain a shaft sleeve blank; (3) Place the sleeve blank into the hot isostatic pressing equipment for hot isostatic pressing treatment.

[0012] Furthermore, in step (1), the sleeve base material is 316L stainless steel.

[0013] Furthermore, in step (2), the method for obtaining the spraying thickness of the gradient layer is: (1) Design the sleeve engineering drawing according to the dimensions of the sinking roller and support arm of the hot dip galvanizing unit to obtain the sleeve dimensions; (2) According to the size of the sleeve, the hot dip plating process is continuously simulated and analyzed using finite element simulation software to obtain the temperature field and stress field of the sleeve in the thermal equilibrium state; (3) According to the temperature field and stress field of the sleeve, the point where the stress corresponds to the thermal fatigue strength at the temperature is determined as the critical failure point, and all critical failure points form a failure surface; (4) The point on the failure surface that is farthest from the sleeve surface is taken as the critical failure point of the entire sleeve. The distance from this point to the sleeve surface is the failure depth, which is the spray thickness of the gradient layer. Furthermore, the number of layers of the gradient layer is determined by the failure depth. The larger the failure depth, the more layers there are.

[0014] Furthermore, in step (3), the process conditions of hot isostatic pressing treatment are as follows: treatment temperature is 1100° C., pressure is 110 MPa, and holding time is 2 to 3 hours.

[0015] Furthermore, in step (3), the shaft sleeve blank is subjected to grinding and polishing after hot isostatic pressing.

[0016] The beneficial effects of the present invention are: (1) The gradient layer of the present invention serves as the main stress-bearing part of the shaft sleeve. The gradient layer contains a ceramic material composited with a nickel alloy or a cobalt alloy. The ceramic is a partial component of the surface gradient layer. Due to its good high temperature performance and wear resistance, the ability of the shaft sleeve material to resist failure is improved. At the same time, the raw material content of the gradient layer of the present invention is set in a gradient manner. The percentage of the ceramic powder coated in the gradient layer increases from the inside to the outside in a step-by-step manner, so that the surface of the material gradually becomes harder from the inside to the outside and can resist wear. At the same time, the percentage of the alloy powder decreases from the inside to the outside in a step-by-step manner, so that the composition and structure inside the material gradually transition, thereby reducing stress concentration and defects at the interface, which helps to improve the overall strength and stability of the material.

[0017] (2) The coated ceramic powder used in the gradient layer of the present invention is a ceramic powder with a Ni film or a Co film coated on the surface. Since nickel alloy or cobalt alloy powder is a self-fluxing alloy, the Ni film or the Co film on the surface of the ceramic powder enhances the wettability of the ceramic powder and the alloy powder, promotes the fusion of the alloy powder and the ceramic powder in the gradient layer, improves the strength and quality of the gradient layer, overcomes the performance defects of the gradient layer such as easy peeling, and effectively extends the service life of the bushing.

[0018] (3) The nickel alloy or cobalt alloy used in the transition layer of the present invention makes the connection between the sleeve substrate and the gradient layer more tightly, making it less likely to peel off, thereby increasing the service life.

[0019] (4) The transition layer and gradient layer of the present invention are processed by spraying, and the processed surface is smooth and conforms to the surface shape of the sleeve, overcoming a series of defects caused by traditional methods such as plasma spray welding and laser cladding processing technology, such as uneven processing surface, difficulty in achieving continuous gradient changes in metal and ceramic components in surface metal ceramic materials, and inability to effectively process chamfers.

[0020] (5) The hot isostatic pressing technology used in the preparation method of the present invention promotes the bonding of the sleeve spray material and realizes the densification of the sleeve surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 It is a cross-sectional view of a sleeve according to Example 1 of a specific implementation manner of the present invention.

[0023] In the figure, 1-sleeve substrate, 2-transition layer, 3-gradient layer. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0025] Example 1 Example 1 Taking a hot-dip galvanizing sunken roller sleeve (the base is 316L stainless steel) with a diameter of 150 mm and a length of 300 mm as an example, a preparation method of the sleeve is introduced, which specifically includes the following steps: Step 1: Design a hot-dip galvanized sunken roller sleeve engineering drawing with a diameter of 150 mm and a length of 300 mm according to the existing technology.

[0026] Step 2: According to the hot-dip galvanizing process and the engineering drawing of the sunken sleeve, the finite element simulation software is used to continuously simulate and analyze the process of immersion zinc plating of 316L stainless steel at 455°C to obtain the temperature field and stress field of the sleeve under thermal equilibrium; the stress at a certain point of the sleeve is equal to the thermal fatigue strength of 316L stainless steel at the temperature of that point, and this point is the critical failure point; along the surface curve of the sleeve, each critical failure point is connected to form a failure surface of the sleeve, and the area between the failure surface and the sleeve surface is the failure area (the others are non-failure areas); since the depths of the failure areas at different positions on the sleeve surface are different, in order to facilitate processing, the point on the failure surface that is farthest from the sleeve surface is used as the critical failure point of the entire sleeve, and the distance from this point to the sleeve surface is the failure depth. The failure depth of this sleeve is about 4.0mm.

[0027] Step three, such as Figure 1, the sleeve is spatially divided into a sleeve base 1, a transition layer 2 and a gradient layer 3. The thickness of the gradient layer 3 is equal to the failure depth of the sleeve, i.e. 4.0 mm; the total thickness of the transition layer 2 and the sleeve base 1 is the total thickness of the sleeve wall minus the failure depth. The transition layer 2 is between the sleeve base 1 and the gradient layer 3. The thickness of the transition layer 2 is 0.8 mm. The thickness of the sleeve base 1 is the non-failure depth minus the thickness of the transition layer 2: make an engineering drawing of the entire sleeve.

[0028] Step 4, determine the materials of the sleeve substrate 1, transition layer 2 and gradient layer 3: the sleeve substrate 1 is made of heat-resistant and corrosion-resistant 316L stainless steel; the transition layer 2 is made of Ni60 powder; the gradient layer 3 is made of composite powder (a mixture of Ni60 powder and ZrO2 powder coated with Ni film on the surface), and the gradient layer 3 is divided into 5 layers according to its thickness, and each layer is 0.8m thick; the gradient layer 3 is the first to fifth layers from the inside to the outside, and the mass ratios of Ni60 powder to ZrO2 powder coated with Ni film on the surface in the first to fifth layers are 9:1, 8:2, 7:3, 6:4, and 5:5 respectively.

[0029] Step 5: After the materials of the sleeve base 1, the transition layer 2 and the gradient layer 3 are determined, the sleeve base 1 is processed and manufactured using conventional methods.

[0030] Step six: spray Ni60 powder on the surface of the sleeve substrate 1 to form a transition layer 2, and the thickness of the transition layer 2 is 0.8 mm.

[0031] Step seven, spray 5 layers of Ni60 powder and ZrO2 powder coated with Ni film on the transition layer 2 in the mass ratio as in step four, each layer is 0.8mm thick, and each superimposed layer conforms to the shape and size of the corresponding engineering drawing to obtain a sleeve blank.

[0032] Step eight, placing the shaft sleeve blank into a hot isostatic pressing device for hot isostatic pressing treatment at a temperature of 1100° C. and a pressure of 110 MPa for 2 hours.

[0033] Step nine, grinding and polishing the surface of the sleeve after hot isostatic pressing until it meets the roughness requirements.

[0034] The sunken roller sleeve prepared in Example 1 was put into continuous operation in a zinc pot for more than 35 days, and the technical effect of stability without vibration and without surface peeling was obtained.

[0035] Example 2 Example 2 Taking a hot-dip galvanizing sunken roller sleeve (the base is 316L stainless steel) with a diameter of 200 mm and a length of 350 mm as an example, a preparation method of the sleeve is introduced, which specifically includes the following steps: Step 1: Design a hot-dip galvanized sunken roller sleeve engineering drawing with a diameter of 200 mm and a length of 350 mm according to the existing technology.

[0036] Step 2: According to the hot-dip galvanizing process and the engineering drawing of the sunken sleeve, the finite element simulation software is used to continuously simulate and analyze the process of immersion zinc plating of 316L stainless steel at 450°C to obtain the temperature field and stress field of the sleeve under thermal equilibrium; the stress at a certain point of the sleeve is equal to the thermal fatigue strength of 316L stainless steel at the temperature of that point, and this point is the critical failure point; along the surface curve of the sleeve, each critical failure point is connected to form a failure surface of the sleeve, and the area between the failure surface and the sleeve surface is the failure area (the others are non-failure areas); since the depths of the failure areas at different positions on the sleeve surface are different, in order to facilitate processing, the point on the failure surface that is farthest from the sleeve surface is used as the critical failure point of the entire sleeve, and the distance from this point to the sleeve surface is the failure depth. The failure depth of this sleeve is about 5.0mm.

[0037] Step three, divide the sleeve into a sleeve base, a transition layer and a gradient layer in space. The thickness of the gradient layer is equal to the failure depth of the sleeve, that is, 5.0 mm; the total thickness of the transition layer and the sleeve base is the total thickness of the sleeve wall minus the failure depth. The transition layer is between the sleeve base and the gradient layer, and the thickness of the transition layer is 1.0 mm. The thickness of the sleeve base is the non-failure depth minus the thickness of the transition layer: make an engineering drawing of the entire sleeve.

[0038] Step 4, determine the materials of the sleeve substrate, transition layer and gradient layer: the sleeve substrate is made of heat-resistant and corrosion-resistant 316L stainless steel; the transition layer is made of Co40 powder; the gradient layer is made of composite powder (a mixture of Co40 powder and TiO2 powder coated with Co film on the surface), and the gradient layer is divided into 5 layers according to its thickness, and each layer is 1.0m thick; the gradient layers are the first to fifth layers from the inside to the outside, and the mass ratios of Co40 powder to TiO2 powder coated with Co film on the surface in the first to fifth layers are 9:1, 8:2, 7:3, 6:4, and 5:5 respectively.

[0039] Step 5: After the materials of the sleeve base, transition layer and gradient layer are determined, the sleeve base is processed and manufactured using conventional methods.

[0040] Step six, spraying Ni60 powder on the surface of the sleeve substrate to form a transition layer, the thickness of the transition layer is 1.0 mm.

[0041] Step seven, spray the Co40 powder and the TiO2 powder coated with Co film on the transition layer in the mass ratio as in step four in sequence, each layer is 1.0 mm thick, and each superimposed layer conforms to the shape and size of the corresponding engineering drawing to obtain a shaft sleeve blank.

[0042] Step eight, placing the shaft sleeve blank into a hot isostatic pressing device for hot isostatic pressing treatment at a temperature of 1100° C. and a pressure of 110 MPa for 3 hours.

[0043] Step nine, grinding and polishing the surface of the sleeve after hot isostatic pressing until it meets the roughness requirements.

[0044] The sunken roller sleeve prepared in Example 2 was put into continuous operation in a zinc pot for more than 45 days, and a technical effect of stability, no vibration and no surface peeling was obtained.

[0045] Although the present invention has been described in detail with reference to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention.

Claims

1. A sunken roller sleeve for hot dip plating, comprising a sleeve base, characterized in that: A transition layer and a gradient layer are sequentially provided from the surface of the sleeve base to the outside; The raw material of the transition layer is alloy powder, and the raw material of the gradient layer is composite powder of alloy powder and coated ceramic powder; When the alloy powder of the transition layer raw material is nickel alloy powder, the alloy powder in the gradient layer raw material is nickel alloy, and the coated ceramic powder is ceramic powder with a nickel film coated on the surface; When the alloy powder of the transition layer raw material is cobalt alloy powder, the alloy powder in the gradient layer raw material is cobalt alloy, and the coated ceramic powder is ceramic powder with a cobalt film coated on the surface; The percentage of the alloy powder in the gradient layer decreases in a step-like manner from the inside to the outside, and the percentage of the coated ceramic powder in the gradient layer increases in a step-like manner from the inside to the outside.

2. A hot dip coating sink roller sleeve as claimed in claim 1, characterized in that: The ceramic powder in the coated ceramic powder is at least one of Al2O3, ZrO2, TiO2, SiO2, WC, SiC or BN powder.

3. A hot dip coating sink roller sleeve as claimed in claim 1, characterized in that: The gradient layers include the first layer to the fifth layer with equal thickness from the inside to the outside, and the mass ratios of the alloy powder to the coated ceramic powder in the first layer to the fifth layer are 9:1, 8:2, 7:3, 6:4, and 5:5 respectively.

4. A method for preparing a sunken roller sleeve for hot dip coating as claimed in claim 1, characterized in that: The steps include: (1) A layer of alloy powder is sprayed on the surface of the sleeve substrate by direct spraying to form a transition layer; (2) spraying a plurality of layers of composite powder of alloy powder and coated ceramic powder on the surface of the transition layer by layer-by-layer spraying, wherein the percentage of alloy powder decreases and the percentage of coated ceramic powder increases with each layer, and a gradient layer is formed after the layer-by-layer spraying is completed to obtain a shaft sleeve blank; (3) Place the sleeve blank into the hot isostatic pressing equipment for hot isostatic pressing treatment.

5. The method for preparing a sunken roller sleeve for hot dip coating according to claim 4, characterized in that: In step (1), the sleeve base material is 316L stainless steel.

6. The method for preparing a sunken roller sleeve for hot dip coating according to claim 4, characterized in that: In step (2), the method for obtaining the spraying thickness of the gradient layer is: (1) Design the sleeve engineering drawing according to the dimensions of the sinking roller and support arm of the hot dip galvanizing unit to obtain the sleeve dimensions; (2) According to the size of the sleeve, the hot dip plating process is continuously simulated and analyzed using finite element simulation software to obtain the temperature field and stress field of the sleeve in the thermal equilibrium state; (3) According to the temperature field and stress field of the sleeve, the point where the stress corresponds to the thermal fatigue strength at the temperature is determined as the critical failure point, and all critical failure points are connected to form a failure surface; (4) The point on the failure surface that is farthest from the sleeve surface is taken as the critical failure point of the entire sleeve. The distance from this point to the sleeve surface is the failure depth, which is the spray thickness of the gradient layer.

7. The method for preparing a sunken roller sleeve for hot dip coating according to claim 4, characterized in that: In step (3), the process conditions of hot isostatic pressing treatment are as follows: treatment temperature is 1100° C., pressure is 110 MPa, and holding time is 2 to 3 hours.

8. The method for preparing a sunken roller sleeve for hot dip coating according to claim 4, characterized in that: In step (3), the shaft sleeve blank is subjected to hot isostatic pressing and then grinding and polishing.

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