Fe-based alloy powder for laser cladding, composite guide plate and preparation method of composite guide plate

Abstract

The invention discloses Fe-based alloy powder for laser cladding, a composite guide plate and a preparation method of the Fe-based alloy powder. The Fe-based alloy powder for laser cladding comprises the following components: 70.5-75 wt.% of Fe, 15-20 wt.% of Cr, 2-4 wt.% of Ni, 0.5-1 wt.% of Si, 0.3-0.8 wt.% of Mo and 0.1-0.2 wt.% of C. A preparation method of a high-temperature wear-resistant iron-based composite guide plate comprises the following steps that S1, after a base material is polished, oxide skin on the surface is removed, the surface of the base material is cleaned with absolute ethyl alcohol to remove stains, and the base material is dried with cold air; s2, preheating the base material to 200 DEG C; and S3, under the action of a heat source laser beam, the Fe-based alloy powder is molten and solidified on the surface of the base material, and a high-hardness cladding layer resistant to high temperature and abrasion is formed. The Fe-based alloy powder is cladded to the surface of the guide plate in a laser cladding mode to form the cladding layer, so that the abrasion resistance of the side guide plate is greatly improved, the on-line service life of the side guide plate is greatly prolonged, the replacement frequency of the side guide plate is reduced, the ton steel consumption of the side guide plate is obviously reduced, the rolling efficiency is improved, and the strip steel edge quality and the yield are improved to different degrees.

Description

Technical Field

[0001] The invention relates to the field of laser additive manufacturing, and in particular to an Fe-based alloy powder for laser cladding, a composite guide plate and a preparation method thereof. Background Art

[0002] my country is a major steel producer in the world, with an output of more than 1.3 billion tons in 2023, of which hot-rolled strip accounts for about 150 million tons. The side guide plate on the hot-rolled strip production line is one of the important equipment. Through the clamping of the guide plate, the strip is guided, which can keep the strip in the center during high-speed rolling and coiling, so as not to warp or deviate, improve the stability of rolling and coiling, and smoothly enter and pass through the finishing mill or coiler.

[0003] However, the side guides are subject to high-temperature sliding wear from the deviated strip. And as the degree of wear increases, grooves are formed in the working area of ​​the side guides (the part in contact with the strip), which reduces the edge quality of the strip and reduces the rolling and curling stability. If the relative movement speed between the strip and the guide is too fast, it will cause a large impact on the edge of the strip, damaging the edge. In severe cases, it will clamp the waste pile and even cause a steel pile accident. For some strip products with high requirements for edge quality, the maximum wear threshold of the side guides is specified in the rolling process, and the side guides must be replaced in time. Therefore, the high-temperature wear resistance of the guide is of great significance to the stability and precise control of hot rolling. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem of poor high-temperature wear resistance of existing side guide plates, and to provide an Fe-based alloy powder for laser cladding, a composite guide plate and a preparation method thereof.

[0005] The invention discloses an Fe-based alloy powder for laser cladding, comprising the following components: 70.5-75wt.% Fe, 15-20wt.% Cr, 2-4wt.% Ni, 0.5-1wt.% Si, 0.3-0.8wt.% Mo, and 0.1-0.2wt.% C.

[0006] Furthermore, the Fe-based alloy powder is spherical in shape, with a particle size of 50 to 150 μm, and is prepared by vacuum gas atomization.

[0007] A method for preparing a high-temperature wear-resistant iron-based composite guide plate comprises the following steps:

[0008] S1: After polishing the substrate, remove the oxide skin on the surface, clean the substrate surface with anhydrous ethanol to remove stains, and dry it with cold air;

[0009] S2: preheating the substrate to 200°C;

[0010] S3: Under the action of the heat source laser beam, the Fe-based alloy powder is melted and solidified on the surface of the substrate to form a high-hardness cladding layer that is resistant to high temperature and wear.

[0011] Furthermore, before the laser cladding, the Fe-based alloy powder is placed in a vacuum drying oven and dried at a drying temperature of 120° C. for 2 hours.

[0012] Furthermore, in step S3, the laser cladding process adopts a coaxial powder feeding method, and argon is used as a carrier gas for the powder and a protective gas for the cladding process.

[0013] Furthermore, in step S3, the process parameters of laser cladding are: laser output power 2-4 kW, laser spot size 2-4 mm, laser scanning speed 1500-3000 mm / min, powder feeding rate 20-30 g / min, overlap rate 40-60%, shielding gas flow rate 20 L / min, and carrier gas flow rate 3 NL / min.

[0014] Furthermore, in step S3, the laser scanning path is a linear reciprocating type, and the scanning motion mode is realized by a CNC programming machine tool, and the overlap rate of the laser scanning is 50%.

[0015] A high-temperature wear-resistant iron-based composite guide plate is prepared by any one of the above preparation methods.

[0016] The beneficial effects of the present invention are as follows: by laser cladding Fe-based alloy powder onto the guide plate surface to form a cladding layer, the wear resistance and online service life of the side guide plate are greatly improved, the replacement frequency of the side guide plate is reduced, the consumption of side guide plates per ton of steel is significantly reduced, the rolling efficiency is improved, and the edge quality and yield rate of the strip are improved to varying degrees. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of coaxial powder feeding for laser cladding;

[0018] Figure 2 It is the metallographic structure of laser cladding Fe-based alloy cladding layer;

[0019] Figure 3 is the hardness distribution diagram of the cladding layer;

[0020] Figure 4 is the friction coefficient of the cladding layer and the cross section of the wear scar. DETAILED DESCRIPTION

[0021] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0022] Example 1

[0023] A method for preparing a high-temperature wear-resistant iron-based composite guide plate comprises the following steps:

[0024] S1: After polishing the substrate, remove the oxide skin on the surface, clean the substrate surface with anhydrous ethanol to remove stains, and dry it with cold air;

[0025] S2: preheating the substrate to 200°C; by preheating the substrate, the crack resistance of the cladding layer can be improved;

[0026] S3: Under the action of the heat source laser beam, the Fe-based alloy powder is melted and solidified on the surface of the substrate to form a high-hardness cladding layer resistant to high temperature wear. In step S3, the Fe-based alloy powder is placed in a vacuum drying oven at a drying temperature of 120° C. for 2 hours before laser cladding.

[0027] In step S3, the laser cladding process adopts a coaxial powder feeding method, with argon as the carrier gas of the powder and the protective gas during the cladding process. In step S3, the process parameters of laser cladding are: laser output power 2kw, laser spot size 2mm, laser scanning speed 1500mm / min, powder feeding rate 20g / min, overlap rate 40%, protective gas flow rate 20L / min, carrier gas flow rate 3NL / min. In step S3, the laser scanning path is a linear reciprocating type, and its scanning motion mode is realized by a CNC programming machine tool, and the overlap rate of the laser scanning is 40%.

[0028] In this solution, the Fe-based alloy powder includes the following components: 74.5wt.% Fe, 20wt.% Cr, 4wt.% Ni, 0.5wt.% Si, 0.8wt.% Mo, 0.2wt.% C. The Fe-based alloy powder is spherical in shape, with a particle size of 50-150μm, and is prepared by vacuum gas atomization.

[0029] Example 2

[0030] A method for preparing a high-temperature wear-resistant iron-based composite guide plate comprises the following steps:

[0031] S1: After polishing the substrate, remove the oxide skin on the surface, clean the substrate surface with anhydrous ethanol to remove stains, and dry it with cold air;

[0032] S2: preheating the substrate to 200°C; by preheating the substrate, the crack resistance of the cladding layer can be improved;

[0033] S3: Under the action of the heat source laser beam, the Fe-based alloy powder is melted and solidified on the surface of the substrate to form a high-hardness cladding layer resistant to high temperature wear. In step S3, the Fe-based alloy powder is placed in a vacuum drying oven at a drying temperature of 120° C. for 2 hours before laser cladding.

[0034] In step S3, the laser cladding process adopts a coaxial powder feeding method, and argon is used as the carrier gas of the powder and the protective gas during the cladding process. In step S3, the process parameters of laser cladding are: laser output power 3kw, laser spot size is 3mm, laser scanning speed is 2000mm / min, powder feeding rate is 25g / min, overlap rate is 50%, protective gas flow rate is 20L / min, and carrier gas flow rate is 3NL / min. In step S3, the laser scanning path is a linear reciprocating type, and its scanning motion mode is realized by a CNC programming machine tool, and the overlap rate of laser scanning is 40%.

[0035] In this solution, the Fe-based alloy powder includes the following components: 75wt.% Fe, 20wt.% Cr, 3.5wt.% Ni, 1wt.% Si, 0.3wt.% Mo, 0.2wt.% C. The Fe-based alloy powder is spherical in shape, with a particle size of 50-150μm, and is prepared by vacuum gas atomization.

[0036] Example 3

[0037] A method for preparing a high-temperature wear-resistant iron-based composite guide plate comprises the following steps:

[0038] S1: After polishing the substrate, remove the oxide skin on the surface, clean the substrate surface with anhydrous ethanol to remove stains, and dry it with cold air;

[0039] S2: preheating the substrate to 200°C; by preheating the substrate, the crack resistance of the cladding layer can be improved;

[0040] S3: Under the action of the heat source laser beam, the Fe-based alloy powder is melted and solidified on the surface of the substrate to form a high-hardness cladding layer resistant to high temperature wear. In step S3, the Fe-based alloy powder is placed in a vacuum drying oven at a drying temperature of 120° C. for 2 hours before laser cladding.

[0041] In step S3, the laser cladding process adopts a coaxial powder feeding method, with argon as the carrier gas of the powder and the protective gas during the cladding process. In step S3, the process parameters of laser cladding are: laser output power 4kw, laser spot size 4mm, laser scanning speed 3000mm / min, powder feeding rate 30g / min, overlap rate 50%, protective gas flow rate 20L / min, carrier gas flow rate 3NL / min. In step S3, the laser scanning path is a linear reciprocating type, and its scanning motion mode is realized by a CNC programming machine tool, and the overlap rate of laser scanning is 40%.

[0042] In this solution, the Fe-based alloy powder includes the following components: 75wt.% Fe, 20wt.% Cr, 3wt.% Ni, 1wt.% Si, 0.8wt.% Mo, and 0.2wt.% C. The Fe-based alloy powder is spherical in shape, with a particle size of 50-150μm, and is prepared by vacuum gas atomization.

[0043] In the above-mentioned embodiments 1 to 3, the powder feeding method of laser cladding is pneumatic coaxial powder feeding, and argon gas is used as the protective gas and the carrier gas. The powder is gathered under the action of the Ar2 flow and coupled with the light spot. The schematic diagram of laser cladding is shown in FIG. Figure 1 To improve the crack resistance of the cladding layer, the substrate is prefabricated to 200°C before cladding.

[0044] The composite guide plate obtained in Example 1 was selected, and under the action of a high energy density laser beam, the Fe-based alloy powder and the substrate surface were rapidly melted to form a molten pool. Figure 2 The metallographic structure of the Fe-based alloy cladding layer clad by laser cladding shows that the Fe and Cr atoms in the alloy form a Fe-Cr solid solution. Figure 2 d) and middle ( Figure 2 C) forms columnar crystals, and equiaxed crystals form on the top ( Figure 2 a), the grains gradually become finer from bottom to top.

[0045] The cladding layer was cut to prepare the sample and its hardness distribution was tested. The results are as follows: Figure 3 As shown, the microhardness of the cladding layer is between 950 and 1500 HV, with an average hardness of 992 HV. The hardness of the substrate is between 100 and 250 HV, which is much smaller than the hardness of the cladding layer. Through this method, the hardness of the cladding layer is significantly improved compared with the substrate.

[0046] The friction coefficient and wear scar cross section of the sample were analyzed. The measured data are as follows: Figure 4 As shown, Figure 4(a) is a friction curve, where the average friction coefficient of the substrate is 0.65, and the average friction coefficient of the cladding layer is 0.4. The average friction coefficient of the cladding layer is significantly lower than that of the substrate, and the friction reduction effect is improved. At the same time, compared with the substrate, the fluctuation of the friction coefficient of the cladding layer during the friction process is reduced, and the friction and wear stability is significantly improved.

[0047] Figure 4 The wear scar profile size in (b) shows that the wear scar width and depth of the cladding layer are significantly smaller than those of the substrate, and the wear resistance is excellent.

[0048] The hardness distribution diagram, metallographic structure and friction measurement diagram of the cladding layer of Examples 2 and 3 are the same as those of Example 1.

[0049] Therefore, the technical solution of the present invention can effectively improve the wear resistance and service life of the side guide plate.

[0050] The above-mentioned embodiments only express the specific implementation of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. An Fe-based alloy powder for laser cladding, characterized in that: Includes the following ingredients: 70.5~75wt.%Fe, 15~20wt.%Cr, 2~4wt.%Ni, 0.5~1wt.%Si, 0.3~0.8wt.%Mo, 0.1~0.2wt.%C.

2. The Fe-based alloy powder for laser cladding according to claim 1, characterized in that: The Fe-based alloy powder is spherical in shape, with a particle size of 50 to 150 μm, and is prepared by vacuum gas atomization.

3. A method for preparing a high-temperature wear-resistant iron-based composite guide plate, characterized in that: The following steps are involved: S1: After polishing the substrate, remove the oxide skin on the surface, clean the substrate surface with anhydrous ethanol to remove stains, and dry it with cold air; S2: preheating the substrate to 200°C; S3: Under the action of the heat source laser beam, the Fe-based alloy powder is melted and solidified on the surface of the substrate to form a high-hardness cladding layer that is resistant to high temperature and wear.

4. The method for preparing a high temperature wear-resistant iron-based composite guide plate according to claim 3, characterized in that: Before the laser cladding, the Fe-based alloy powder is placed in a vacuum drying oven and dried at a drying temperature of 120° C. for 2 hours.

5. The method for preparing a high temperature wear-resistant iron-based composite guide plate according to claim 3, characterized in that: In step S3, the laser cladding process adopts a coaxial powder feeding method, and argon is used as a carrier gas for the powder and a protective gas for the cladding process.

6. The method for preparing a high temperature wear-resistant iron-based composite guide plate according to claim 3, characterized in that: In step S3, the process parameters of laser cladding are: laser output power 2-4 kW, laser spot size 2-4 mm, laser scanning speed 1500-3000 mm / min, powder feeding rate 20-30 g / min, overlap rate 40-60%, shielding gas flow rate 20 L / min, and carrier gas flow rate 3 NL / min.

7. The method for preparing a high temperature wear-resistant iron-based composite guide plate according to claim 3, characterized in that: In step S3, the laser scanning path is a linear reciprocating type, and the scanning motion mode is realized by a numerically controlled programming machine tool, and the overlap rate of the laser scanning is 50%.

8. A high temperature wear-resistant iron-based composite guide plate, characterized in that: Prepared by any one of the preparation methods of claims 3 to 7.

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