Iron-based alloy material for laser manufacturing and remanufacturing of steel long product rolls and its preparation method

Abstract

The present invention belongs to the field of alloy material technology, specifically relating to an iron-based alloy material for laser manufacturing of long steel rolls and a preparation method thereof. The iron-based alloy material of the present invention, the alloy powder material, comprises the following components by weight: La: 0.3-2%, Cr: 5-13%, Ni: 2-6%, Ti: 0.5-4%, B: 2-5%, Nb: 1-3%, and Fe: the balance. The present invention designs a laser composite manufacturing method for small-spot thin-layer cladding, successfully producing a cladding layer with a thickness greater than 10 mm.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloy materials, and in particular relates to an iron-based alloy material for use in laser manufacturing of steel long product rolls and a preparation method thereof. Background Art

[0002] Rollers are one of the main consumable spare parts in steel rolling production, accounting for approximately 5% to 15% of the production cost. Roller quality not only affects steel rolling costs and mill availability, but also significantly impacts rolled product quality. With the advancement of steel rolling technology, increasing mill speeds and automation levels have placed higher demands on roll quality, particularly wear resistance, strength, and toughness. Changing roll material is a key measure to improve roll performance. This is especially true for long products, where automated control is the future trend, leading to a growing demand for composite roll manufacturing to enhance performance.

[0003] According to their main materials, rolls can be divided into cast steel rolls (cast steel and semi-steel rolls), forged rolls (forged alloy steel rolls, forged semi-steel rolls, forged semi-high-speed steel rolls, forged white cast iron rolls) and cast iron rolls (ordinary cast iron rolls, high nickel-chromium infinitely chilled cast iron rolls, high chromium cast iron rolls, alloy ductile iron rolls and multi-alloy white cast iron rolls), as well as carbide rolls on profiles, but none of them can meet the increasingly high-speed rolling needs.

[0004] The application of laser technology to surface modification is a new research field opened up by scientific and technological developments, particularly advancements in laser technology and further research in materials theory. Compared to traditional energy sources, lasers offer more concentrated energy and more precise controllability. Laser cladding technology can form very thin, low-dilution coatings on material surfaces, making it suitable for both large-scale and localized surface modification. Summary of the Invention

[0005] Based on the aforementioned problems with the existing technologies, the present invention aims to provide an iron-based alloy material for laser manufacturing of long steel rolls and its preparation method. Currently, high-speed steel rolls offer excellent performance and meet the requirements of roll operating conditions. High-speed steel rolls offer excellent performance, but their preparation is complex and the cost of long steel rolls is high. The present invention designs an alloy material for laser cladding to produce a wear-resistant coating, which can reduce costs while improving performance. The present invention designs a high-speed steel material with a high alloy content for rolls and completes the preparation of laser cladding powder material.

[0006] Due to the performance requirements of the roll collar, the selected cladding material, when produced using traditional pre-powder cladding methods, suffers from numerous internal pores and macroscopic cracks after cladding. To address these issues, the present invention has designed a laser composite manufacturing method for small-spot, thin-layer cladding, successfully producing cladding layers greater than 10 mm thick.

[0007] The present invention adopts the following technical solutions.

[0008] A laser-made iron-based alloy material for use in steel long product rolls. The alloy powder material comprises the following components in percentage by mass: La: 0.3-2%, Cr: 5-13%, Ni: 2-6%, Ti: 0.5-4%, B: 2-5%, Nb: 1-3%, and Fe: the remainder.

[0009] Furthermore, the alloy powder has a particle size of -100-+325 mesh.

[0010] Furthermore, the alloy powder material is prepared through vacuum melting, vacuum gas atomization, screening and other processes.

[0011] A method for preparing a steel long product roll using laser manufacturing, comprising the following steps:

[0012] Step 1: Dry the powder used for laser cladding at 120°C for 2 hours. After the powder is dried, air cool it in a drying furnace. After cooling to room temperature, add it to the powder feeding chamber of the airborne powder feeder.

[0013] Step 2: Program the stacking strategy of the roller ring, with an inter-layer avoidance distance of 0.2~0.5mm;

[0014] Step 3: Clamp the roller ring on the three-jaw positioner, and use heat insulation material to isolate the roller ring from the positioner jaws;

[0015] Step 4: Adjust the focal length of the laser cladding powder feeding head and the distance between the powder spot and the work surface to ensure that the powder spot of the ring-shaped powder feeding is focused on the work surface to be clad. After the focal length adjustment is completed, adjust the relative position of the induction heater coil and the workpiece to ensure that the induction heating coil and the workpiece do not interfere with each other during the construction process;

[0016] Step 5: Close the atmosphere chamber door and open the inflation valve to gradually reduce the oxygen content in the chamber;

[0017] Step 6: When the oxygen content in the cabin drops to 2% to 6%, turn on the induction heating device to heat the roller ring;

[0018] Step 7: After the roller ring is uniformly preheated to 350°C using induction heating and the oxygen content in the chamber is less than 100 ppm, the laser cladding program is started to begin the roller ring laser composite remanufacturing.

[0019] Furthermore, the cladding process parameters are: power: 1000~2800 W, spot diameter: 1.8~3.6 mm, scanning speed: 45~85 mm / s, and powder feeding rate 6~20 g / min.

[0020] Furthermore, the thickness of the cladding layer is 0.3~0.35mm, and the cladding is performed layer by layer, and the final forming thickness is 10~11mm.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] Ti and Nb are appropriately added to the iron-based alloy of the functional layer: Ti, as a strong reducing element, can form high-melting-point compounds with elements such as C and N in the molten pool, preventing C and N from reacting with oxygen to form gases such as CO and CO2, thereby reducing the generation of pores in the cladding layer (such as Figure 1 As shown in Figure 2), the metal compounds of Nb element can act as nucleation particles to achieve the effect of grain refinement, thereby improving the uniformity of the cladding layer and enhancing the mechanical properties.

[0023] The cladding process is carried out in an argon chamber with an oxygen content of less than 100 ppm. In a low oxygen content environment, the generation of inclusions and pores inside the cladding layer can be avoided, thereby improving the cladding quality.

[0024] Small spot thin layer laser cladding is used. In the field of laser cladding, such a thin cladding layer thickness is relatively rare. The cladding layer thickness is controlled at 0.1~0.5mm. When the cladding layer is thin, the pores generated during the cladding process will be more likely to overflow under the condition of thin cladding layer, thereby reducing the internal pore tendency of the cladding layer and improving the cladding quality.

[0025] Induction heating is used to increase the substrate temperature. The substrate is preheated to 300~500℃ by induction heating. The increase in substrate temperature is beneficial to the convection behavior inside the molten pool, thereby further promoting the elimination of pores. At the same time, the high substrate preheating temperature can reduce the temperature difference between the substrate and the molten pool, thereby reducing the internal stress of the cladding layer and reducing the risk of cracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Comparison of pores in the cladding layer of Example 1 and the cladding layer of the original alloy (a, pores in the cladding layer of Example 1, b, pores in the cladding layer of the original alloy).

[0027] Figure 2 The results of roller ring flaw detection in Example 1. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] A laser-made high-wear-resistant iron-based alloy material for a rolling mill roll comprises the following components in mass percentage: La: 0.3-2%, Cr: 5-13%, Ni: 2-6%, Ti: 0.5-4%, B: 2-5%, Nb: 1-3%, and Fe: the remainder.

[0030] Furthermore, the alloy powder has a particle size of -100-+325 mesh.

[0031] Furthermore, the alloy powder material is prepared through vacuum melting, vacuum gas atomization, screening and other processes.

[0032] A method for preparing a steel long product roll using laser manufacturing, comprising the following steps:

[0033] Step 1: Dry the powder used for laser cladding at 120°C for 2 hours. After the powder is dried, air cool it in a drying furnace. After cooling to room temperature, add it to the powder feeding chamber of the airborne powder feeder.

[0034] Step 2: Program the stacking strategy of the roller ring, with an inter-layer avoidance distance of 0.2~0.5mm;

[0035] Step 3: Clamp the roller ring on the three-jaw positioner, and use heat insulation material to isolate the roller ring from the positioner jaws;

[0036] Step 4: Adjust the focal length of the laser cladding powder feeding head and the distance between the powder spot and the work surface to ensure that the powder spot of the ring-shaped powder feeding is focused on the work surface to be clad. After the focal length adjustment is completed, adjust the relative position of the induction heater coil and the workpiece to ensure that the induction heating coil and the workpiece do not interfere with each other during the construction process;

[0037] Step 5: Close the atmosphere chamber door and open the inflation valve to gradually reduce the oxygen content in the chamber;

[0038] Step 6: When the oxygen content in the cabin drops to 2% to 6%, turn on the induction heating device to heat the roller ring;

[0039] Step 7: After the roller ring is uniformly preheated to 350°C using induction heating and the oxygen content in the chamber is less than 100 ppm, the laser cladding program is started to begin the roller ring laser composite remanufacturing.

[0040] Furthermore, the cladding process parameters are: power: 1000~2800W, spot diameter: 1.8~3.6mm, scanning speed: 45~85mm / s, and powder feeding rate 6~20g / min.

[0041] Furthermore, the thickness of the cladding layer is 0.3~0.35mm, and the cladding is performed layer by layer, and the final forming thickness is 10~11mm.

[0042] Example 1.

[0043] Remove oil stains, oxides, fatigue layers and other factors that affect the cladding quality on the surface of the roller ring.

[0044] The powder used for laser cladding is dried at a temperature of 120°C for 2 hours. After the powder is dried, it is air-cooled in a drying furnace. After cooling to room temperature, it is added to the powder feeding chamber of the airborne powder feeder.

[0045] The stacking strategy of the roller ring is programmed with an inter-layer avoidance distance of 0.25 mm.

[0046] The roller ring is clamped on the three-jaw positioner. In particular, to ensure that the motor does not overheat and affect its operation during the heating process, insulation material is used to isolate the roller ring from the positioner jaws.

[0047] Adjust the focal length of the laser cladding powder feeding head and the distance between the powder spot and the work surface to ensure that the powder spot of the ring-shaped powder feeding is focused on the work surface to be clad. After the focal length adjustment is completed, adjust the relative position of the induction heater coil and the workpiece to ensure that the induction heating coil and the workpiece do not interfere with each other during the construction process.

[0048] Close the atmosphere cabin door and open the inflation valve to gradually reduce the oxygen content in the cabin.

[0049] To prevent oxidation of the roller ring during the preheating process, when the oxygen content in the cabin drops to 5%, the induction heating equipment is turned on to heat the roller ring. The heating process is slow and gentle to ensure uniform preheating.

[0050] After the roller ring is uniformly preheated to 350°C using induction heating and the oxygen content in the chamber is lower than 100 ppm, the laser cladding program is started and the roller ring laser composite remanufacturing begins.

[0051] After the cladding is completed, the surface is inspected and there are no crack defects such as Figure 2 As shown, the thickness of the cladding layer was measured, and the total thickness was 11 mm. The thickness of a single cladding layer was 0.35 mm.

[0052] After cladding is completed, the roller ring is heat treated and the surface of the functional layer is processed to ensure that it meets customer requirements.

Claims

1. A laser-made iron-based alloy material for steel long product rolls, characterized in that: The alloy material is an alloy powder material, and its mass percentage components are: La: 0.3-2%, Cr: 5-13%, Ni: 2-6%, Ti: 0.5-4%, B: 2-5%, Nb: 1-3%, and Fe: balance.

2. The laser manufacturing method for iron-based alloy material for steel long product rolls according to claim 1, characterized in that: The alloy powder material has a particle size of -100-+325 mesh.

3. The laser manufacturing method for iron-based alloy material for steel long product rolls according to claim 1, characterized in that: The alloy powder material is prepared through vacuum melting, vacuum gas atomization and screening processes.

4. A method for preparing a steel long product roll using the laser manufacturing method of claim 1, wherein the method comprises the following steps: Step 1: Dry the powder used for laser cladding at 120°C for 2 hours. After the powder is dried, air cool it in a drying furnace. After cooling to room temperature, add it to the powder feeding chamber of the airborne powder feeder. Step 2: Program the stacking strategy of the roller ring, with an inter-layer avoidance distance of 0.2~0.5mm; Step 3: Clamp the roller ring on the three-jaw positioner, and use heat insulation material to isolate the roller ring from the positioner jaws; Step 4: Adjust the focal length of the laser cladding powder feeding head and the distance between the powder spot and the work surface to ensure that the powder spot of the ring-shaped powder feeding is focused on the work surface to be clad. After the focal length adjustment is completed, adjust the relative position of the induction heater coil and the workpiece to ensure that the induction heating coil and the workpiece do not interfere with each other during the construction process; Step 5: Close the atmosphere chamber door and open the inflation valve to gradually reduce the oxygen content in the chamber; Step 6: When the oxygen content in the cabin drops to 2% to 6%, turn on the induction heating device to heat the roller ring; Step 7: After the roller ring is uniformly preheated to 350°C using induction heating and the oxygen content in the chamber is less than 100 ppm, the laser cladding program is started to begin the roller ring laser composite remanufacturing.

5. The method for preparing a steel long product roll according to claim 4, characterized in that: The cladding process parameters are: power: 1000~2800 W, spot diameter: 1.8~3.6 mm, scanning speed: 45~85 mm / s, and powder feeding rate 6~20 g / min.

6. The method for preparing a steel long product roll according to claim 4, characterized in that: The thickness of the cladding layer is 0.3~0.35mm, and it is clad layer by layer, and the final forming thickness is 10~11mm.

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