A valve sealing surface surfacing method

Abstract

The present invention discloses a valve sealing surface surfacing method and tooling and its products, relating to the field of valve technology, the specific steps of the method are as follows: S1, first turning a surfacing groove on the valve sealing surface, and then fixing the valve on a rotating workbench; S2, preparing an alloy powder, the raw material composition of the alloy powder (by mass percentage) being: chromium 13-16%, iron 0-0.2%, manganese 1-2%, molybdenum 14-17%, phosphorus 0-0.01%, sulfur 0-0.01%, silicon 0.3-0.8%, tungsten 3-5%, vanadium 0.5-1%, and the balance being nickel; S3, while rotating the valve on the rotating workbench, using a laser to melt the alloy powder to clad the surfacing groove, and finally surfacing to form an alloy layer. The present invention meets the surfacing demand of the valve sealing surface with an irregular valve body, while improving the hardness of the surfacing layer and its bonding effect with the valve sealing surface made of stainless steel, improving the wear resistance, corrosion resistance and erosion resistance of the surfacing layer, and ultimately improving the surfacing effect.

Description

Technical Field

[0001] The present invention relates to the field of valve technology, and in particular to a valve sealing surface surfacing method and tooling and products thereof. Background Art

[0002] Tank containers, which store corrosive liquid chemicals, often have valves installed at the bottom for unloading. However, even if the valve components are made of austenitic stainless steel with a certain degree of corrosion resistance, and the sealing surfaces between the valve body and valve plate are spherical (such as cage-type foot valves) to ensure sealing performance, after long-term use, the valve's sealing surface will no longer be able to maintain its sealing performance after repeated erosion and corrosion by liquid chemicals, eventually leading to leakage of liquid chemicals. The conventional method of strengthening the sealing surface is to weld hard alloy on the valve sealing surface, generally using cobalt-based alloys. However, the cobalt metal in cobalt-based alloys is difficult to extract and has a low recovery rate, resulting in increased costs.

[0003] Currently, cobalt-free alloys are used for hardfacing. Chinese patent publication number CN106956094A discloses a hardfacing alloy material. The article states, "The alloy material comprises the following elements by weight: Nb: 1.0-2.5Wt%, Ni: 0-2.0Wt%, C: 0.3-0.5Wt%, Si: 0.2-0.5Wt%, Mn: 1.0-1.5Wt%, Cr: 3.0-4.0Wt%, Mo: 1.5-2.0Wt%, W+V+Ti: 2.0-2.5Wt%, and the balance is Fe. A method for welding the alloy material comprises depositing the alloy material onto the surface of a steel plate using a tungsten inert gas arc heat source." Although this prior art utilizes a cobalt-free alloy for hardfacing, the improvements in hardness, wear resistance, and corrosion resistance after hardfacing are limited. Furthermore, this method of depositing the alloy material using a tungsten inert gas arc heat source is not suitable for thin-walled sealing surfaces and still faces challenges such as significant post-weld deformation.

[0004] The Chinese patent, publication number CN108326428A, discloses a preparation and surfacing method of nuclear-grade valve surfacing material. The article proposes "using a gas atomization process to prepare an alloy powder with a composition of Fe-(3-5)wt.%Ni-(23-27)wt.%Cr-(1-2)wt.%C, selecting the alloy powder with a particle size of 30 to 80μm and mixing it with BC powder with a particle size of 1-5μm, V powder with a particle size of 5-10μm, Ti powder with a particle size of 5-10μm, and Mo powder with a particle size of 1-5μm to obtain the final surfacing powder. The content of the four powders, BC powder, V powder, Ti powder, and Mo powder is 0.7-1% of the weight of the alloy powder. The five powders are mixed by ball milling. The mixed powder after ball milling is then surfacing-welded on the valve surface by laser cladding." This prior art uses laser cladding to weld nickel-based alloy onto the valve sealing surface, which can meet the welding requirements of thin-walled sealing surfaces. However, the hardness, wear resistance and corrosion resistance of the weld layer formed in this prior art are still average, the media applicable to the valve are limited, and the bonding effect between the weld layer and the valve sealing surface is also average, which ultimately affects the welding effect. At the same time, this prior art does not disclose the path method of laser cladding, and cannot ensure that it is suitable for welding on the valve sealing surface with an irregular valve body.

[0005] Therefore, a new technical solution is needed to solve the above technical problems. Summary of the Invention

[0006] The purpose of the present invention is to provide a valve sealing surface surfacing method and tooling and products thereof, so as to solve the current valve sealing surface surfacing method proposed in the above-mentioned background technology. After the alloy material is surfacing on the valve sealing surface by laser cladding to form a surfacing layer, the hardness, wear resistance and corrosion resistance of the surfacing layer are still average, the medium applicable to the valve is limited, and the bonding effect between the surfacing layer and the valve sealing surface is also average, which ultimately affects the surfacing effect. At the same time, this surfacing method cannot ensure the technical problem of being applicable to surfacing of valve sealing surfaces with irregular valve bodies.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a valve sealing surface surfacing method, the specific steps of which are as follows:

[0009] S1. First, turn the valve sealing surface to form a surfacing groove, and then fix the valve on the rotating workbench;

[0010] S2. Prepare alloy powder, the alloy powder consisting of the following raw materials in percentage by mass: 13-16% chromium, 0-0.2% iron, 1-2% manganese, 14-17% molybdenum, 0-0.01% phosphorus, 0-0.01% sulfur, 0.3-0.8% silicon, 3-5% tungsten, 0.5-1% vanadium, and the balance nickel, the raw materials all having a particle size of 53-150 mesh;

[0011] S3. While rotating the valve on the rotary worktable, use laser to melt alloy powder to clad the cladding groove at a cladding speed of 1.8-2.2 mm / s, and finally form an alloy layer by cladding. Specifically, first, after the alloy powder prepared in step S2 is loaded into the powder bin, the alloy powder in the powder bin is fed into the nozzle of the laser cladding welding gun by using an inert gas. Then, the valve is rotated by the rotary worktable. At the same time, the laser cladding welding gun is operated to move by an articulated robot, and alloy powder and laser beam are synchronously ejected from the nozzle, so that the alloy powder is melted into a liquid state and then drips onto the cladding groove to form an alloy layer. Finally, the alloy layer is machined to form a cladding layer.

[0012] Furthermore, the inert gas is compressed inert gas, the laser beam is a 20-24 kW laser beam, the thickness of the alloy layer is 1.8-2.2 mm, and the thickness of the surfacing layer is 0.8-1.2 mm.

[0013] In the second aspect, the present invention provides a cladding tool for the above-mentioned valve sealing surface cladding method, comprising a laser cladding welding gun, a powder bin, an articulated robot, and a rotary worktable for driving the valve to rotate, wherein the powder bin is connected to the nozzle of the laser cladding welding gun, and the laser cladding welding gun is arranged at the end of the articulated robot, and the powder bin is also connected to an inert gas delivery pipe, wherein the diameter of the nozzle is 5.8-6.2 mm.

[0014] In a third aspect, the present invention further provides a valve obtained by surfacing welding using the above-mentioned valve sealing surface surfacing method and surfacing welding tooling.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. In the present invention, a surfacing groove is first formed by turning on the valve sealing surface, and then the laser is used to melt the alloy powder to clad the surfacing groove while the valve is rotated by a rotary worktable, thereby completing the surfacing. During the entire process, the welding path is realized by the rotation of the valve, thereby meeting the surfacing requirements of the irregular valve sealing surface of the valve body, greatly improving the adaptability of the surfacing method. At the same time, the alloy powder is composed of the following raw materials in terms of mass percentage: chromium 13-16%, iron 0-0.2%, manganese 1-2%, molybdenum 14-17%, phosphorus 0-0.01%, The setting of sulfur 0-0.01%, silicon 0.3-0.8%, tungsten 3-5%, vanadium 0.5-1%, and the balance of nickel makes the alloy of the final cladding layer a nickel-based alloy. On the basis of nickel accounting for more than half of the alloy, forming a stable austenite structure and solid dissolving more alloying elements, chromium, nickel and molybdenum are used as the main elements of the alloy. The elements iron, manganese, phosphorus, sulfur, silicon, tungsten and vanadium work synergistically with chromium, nickel and molybdenum to greatly improve the hardness of the cladding layer and its bonding effect with the valve sealing surface of stainless steel, improve the wear resistance, corrosion resistance and erosion resistance of the cladding layer, effectively improve the cladding effect, and make the valve after cladding meet the sealing requirements of various media;

[0017] 2. In the present invention, while using laser to melt alloy powder to clad the cladding groove, the operation of the rotary valve on the rotary table effectively ensures the uniformity of the composition and structure of the formed cladding layer, thereby improving the cladding effect;

[0018] 3. The cladding welding tooling of the present invention consists of a laser cladding welding gun, a powder bin, an articulated robot, and a rotary worktable. The laser cladding welding gun is located at the end of the articulated robot. The coordinated arrangement of the powder bin and the nozzle of the laser cladding welding gun, combined with the existing control mechanism, ensures smooth implementation of the welding path during valve rotation, thereby further ensuring the cladding applicability to the irregular sealing surface of the valve body and the uniformity of the cladding layer's structure.

[0019] 4. The provision of the inert gas delivery pipe in the present invention not only plays the role of delivering the alloy powder in the powder bin into the nozzle of the laser cladding welding gun, but also effectively avoids the oxidation of the alloy powder, thereby further ensuring the cladding effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the working principle of the present invention;

[0021] Figure 2 for Figure 1 A partial enlarged view of point A in the middle;

[0022] Figure 3 Valves with weld overlay grooves formed for turned pins (valve plates omitted);

[0023] Figure 4 This is a schematic diagram of the surfacing welding state of the valve sealing surface of the present invention;

[0024] In the figure: 1. Powder bin, 2. Inert gas delivery pipe, 3. Articulated robot, 4. Rotary worktable, 5. Laser cladding welding gun, 51. Nozzle, 6. Overlay welding tank. DETAILED DESCRIPTION

[0025] The following examples are used to further illustrate the present invention but are not intended to limit its application. Example 1:

[0026] Surfacing welding of valve sealing surface:

[0027] like Figure 1-4 As shown, first, a build-up welding groove 6 is formed by turning on the sealing surface of the valve (valve body), and then the valve is fixed on the rotary table 4 (the basic structures such as the clamping mechanism and the rotating mechanism of the existing rotary table are not described in detail here, but this should not limit its functional realization);

[0028] Then, first, a laser cladding welding gun 5 (the function and structure of the laser cladding welding gun are well known in the art, and the connection setting is also common knowledge, so no further explanation is given here, and it is not shown in detail in the accompanying drawings) is installed on the end of the articulated robot 3 (the basic structures such as the control mechanism and drive mechanism of a normal articulated robot are not described in detail here, but this should not limit the function realization), and then the powder bin 1 is connected to the inert gas delivery pipe 2 and the nozzle 51 of the laser cladding welding gun 5 at the same time (the diameter is 5.8-6.2 mm, and the basic structures such as the powder nozzle and laser nozzle of the nozzle of a normal laser cladding welding gun are not described in detail here, but this should not limit the function realization), after the alloy powder is loaded into the powder bin 1, the alloy powder in the powder bin 1 is fed into the nozzle 51 of the laser cladding welding gun 5 through the inert gas delivery pipe 2 using inert gas;

[0029] Then, the valve is rotated by the rotary table 4, and the laser cladding welding gun 5 is operated by the articulated robot 3 to move. The alloy powder and a 20-24 kW laser beam are simultaneously ejected from the nozzle 51 of the laser cladding welding gun 5, causing the alloy powder to melt into a liquid state and then drip onto the cladding groove. The liquid alloy powder combines with the surface of the cladding groove 6 at a high temperature to form an alloy layer with a thickness of 1.8-2.2 mm (at a speed of 1.8-2.2 mm / s).

[0030] Finally, the alloy layer is machined to form a 0.8-1.2mm thick overlay layer.

[0031] In addition, the raw material composition of the above-mentioned alloy powder is (by mass percentage): chromium powder 14.5%, iron powder 0.1%, manganese powder 1.5%, molybdenum powder 15.5%, phosphorus powder 0.005%, sulfur powder 0.005%, silicon powder 0.55%, tungsten powder 4%, vanadium powder 0.75%, nickel powder 63.09%, and the particle size of each raw material is 53-150 mesh. Example 2:

[0032] Surfacing welding of valve sealing surface:

[0033] The raw material composition of the alloy powder in this embodiment is (by mass percentage) as follows: chromium powder 13%, manganese powder 1%, molybdenum powder 14%, silicon powder 0.3%, tungsten powder 3%, vanadium powder 0.5%, and nickel powder 68.2%.

[0034] The rest of the surfacing method is the same as in Example 1. Example 3:

[0035] Surfacing welding of valve sealing surface:

[0036] The raw material composition of the alloy powder in this embodiment is (by mass percentage) as follows: chromium powder 16%, iron powder 0.2%, manganese powder 2%, molybdenum powder 17%, phosphorus powder 0.01%, sulfur powder 0.01%, silicon powder 0.8%, tungsten powder 5%, vanadium powder 1%, and nickel powder 57.98%.

[0037] The rest of the surfacing method is the same as in Example 1.

[0038] The hardness of the cladding layers of the valves prepared in Examples 1-3 was tested using a Rockwell hardness tester. The hardness of the cladding layers obtained by the test was between HRC180-198.

Claims

1. A valve sealing surface surfacing method, characterized in that: The specific steps are as follows: S1. First, turn the valve sealing surface to form a surfacing groove, and then fix the valve on the rotating workbench; S2. Prepare an alloy powder composed of the following raw materials in percentage by mass: 13-16% chromium, 0-0.2% iron, 1-2% manganese, 14-17% molybdenum, 0-0.01% phosphorus, 0-0.01% sulfur, 0.3-0.8% silicon, 3-5% tungsten, 0.5-1% vanadium, and the balance nickel; S3. While the valve is being rotated on the rotary table, the laser is used to melt the alloy powder to clad the cladding groove at a speed of 1.8-2.2 mm / s, and finally the alloy layer is formed by cladding. The specific operation process of S3 is as follows: First, after the alloy powder prepared in step S2 is loaded into the powder bin, the alloy powder in the powder bin is fed into the nozzle of the laser cladding welding gun using compressed inert gas. Then, the valve is rotated by the rotary worktable. At the same time, the laser cladding welding gun is operated by the articulated robot to move, and the alloy powder and the 20-24KW laser beam are synchronously ejected from the nozzle, so that the alloy powder is melted into a liquid state and then drips onto the cladding groove, forming an alloy layer with a thickness of 1.8-2.2mm. Finally, the alloy layer is machined to form a cladding layer with a thickness of 0.8-1.2mm.

2. A valve sealing surface surfacing method according to claim 1, characterized in that: In step S2, the particle size of the raw materials is 53-150 mesh.

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