Hard alloy powder for wear-resistant layer of heavy-load universal cross shaft and laser cladding method

Abstract

The invention discloses hard alloy powder for a wear-resistant layer of a heavy-load universal cross shaft. The hard alloy powder comprises the following components in percentage by weight: 14-19% of Cr, 1.0-2.1% of Ni, 0.5-1.3% of Mo, 1-2% of B and 1-1.5% of Si, 0.2% C, lt; 0.7% of Mn and the balance Fe; and the particle size is 53-108 [mu] m. Meanwhile, the invention discloses a laser cladding method for the wear-resistant layer of the heavy-load universal cross shaft, which comprises the following specific steps of: treating the shaft neck; preheating: keeping the temperature at 250-300 DEG C for 1 hour; carrying out laser cladding; and slowly cooling. The hard alloy powder is subjected to laser cladding to obtain the wear-resistant layer of the cross shaft, the binding force between the wear-resistant layer and a base body is high, and thermal deformation is small. Meanwhile, the wear-resistant layer is good in hardness, wear resistance, impact resistance and fatigue resistance, so that the service life of the cross shaft is prolonged, and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to a hard alloy powder used for a wear-resistant layer and a laser cladding method for the wear-resistant layer when repairing a heavy-duty universal cross shaft after wear. Background Art

[0002] Heavy-duty and extra-heavy-duty cross-shaft universal couplings are widely used in the main drive devices of heavy machinery such as hot continuous rolling roughing mills, large-section steel rolling mills, piercing mills, medium and heavy plate mills, and coilers. They are huge in size, with a working rotation diameter of 650 mm to 1300 mm and a torque of 2300 KN·m to 19405 KN·m, resulting in a large impact load and torque during operation. On the other hand, the coupling is also subjected to a very high-frequency alternating impact load during operation. Therefore, the key component, the universal cross shaft, in the heavy-duty and extra-heavy-duty cross-shaft universal coupling is extremely prone to wear and the phenomenon of spalling on the shaft head surface.

[0003] According to the different surface spalling conditions of the heavy-duty universal cross shaft, the repair methods are also different, mainly including the following situations: 1. Slight spalling (shallow surface wear): The spalled area is finely ground to restore the surface flatness, which is applicable to the case where the spalling depth < 0.1 mm; 2. Moderate spalling (spalling depth 0.1 - 0.3 mm): There are mainly two repair methods: One is to use the metal spraying technology to repair the spalled position. The wear-resistant alloy layer is sprayed on the journal using the arc spraying or plasma spraying technology, and then the dimensional accuracy is restored through grinding. In this repair method, the wear-resistant alloy layer and the cross shaft body are mechanically combined, and the bonding force is weak, and the repair layer is prone to fall off during use; The other is to use the surfacing of hard alloy layer to repair the spalled position. This method is prone to thermal deformation; 3. Severe spalling (depth exceeding 0.3 mm or cracks appearing): Directly replace the cross shaft, which has a high cost. Summary of the Invention

[0004] The problem to be solved by the present invention is to provide a hard alloy powder for the wear-resistant layer of a heavy-duty universal cross shaft and a laser cladding method. The hard alloy powder is used to obtain the wear-resistant layer of the cross shaft through laser cladding, which has a strong bonding force with the matrix and small thermal deformation. At the same time, the wear-resistant layer has good hardness, wear resistance, impact resistance, and fatigue resistance, thereby prolonging the service life of the cross shaft and reducing the cost.

[0005] The hard alloy powder for the wear-resistant layer of the heavy-duty universal cross shaft of the present invention has the following percentage of components: 14 - 19% Cr, 1.0 - 2.1% Ni, 0.5 - 1.3% Mo, 1 - 2% B, 1 - 1.5% Si, < 0.2% C, < 0.7% Mn, and the balance is Fe; the particle size is 53 - 108 μm.

[0006] Further, the composition of the cemented carbide powder is preferably 18% Cr, 1.8% Ni, 1.1% Mo, 1.5% B, 1.2% Si, <0.2% C, <0.6% Mn, and the balance is Fe.

[0007] Further, the composition of the cemented carbide powder is preferably 17% Cr, 1.8% Ni, 1.2% Mo, 1.5% B, 1.4% Si, <0.2% C, <0.5% Mn, and the balance is Fe.

[0008] Further, the composition of the cemented carbide powder is preferably 17.2% Cr, 1.6% Ni, 1.1% Mo, 1.3% B, 1.2% Si, <0.2% C, <0.5% Mn, and the balance is Fe.

[0009] The laser cladding method for the wear-resistant layer of the heavy-duty universal joint cross shaft of the present invention specifically comprises the following steps: treating the journal; preheating: 250°C - 300°C, holding for 1 h; laser cladding; slow cooling.

[0010] Among them: when the repair dimension of the journal of the heavy-duty universal joint cross shaft is 0.2 mm, the specific steps are as follows: Ⅰ. Grinding the exfoliation part of the journal to remove surface rust and oil, and making the exfoliation part smoothly transition to other positions; Ⅱ. Using a heating tape to wrap for preheating, with a preheating temperature of 250°C and holding for 1 h; Ⅲ. Using a round spot optical head for laser cladding: the spot diameter is 5 mm, the cladding power is 3.0 KW, the scanning speed is 720 mm / min, and the single-layer cladding thickness is 1.1 mm; Ⅳ. After cladding, using an asbestos blanket to wrap the workpiece for slow cooling.

[0011] Among them: when the repair dimension of the journal of the heavy-duty universal joint cross shaft is 1.5 mm, the specific steps are as follows: Ⅰ. Grinding the exfoliation part of the journal to remove surface rust and oil, and making the exfoliation part smoothly transition to other positions; Ⅱ. Using a heating tape to wrap for preheating, with a preheating temperature of 300°C and holding for 1 h; Ⅲ. Using a round spot optical head for laser cladding: the spot diameter is 5 mm, the cladding power is 3.2 KW, the scanning speed is 720 mm / min, and a total of two layers are cladded, with a single-layer cladding thickness of 1.3 mm; Ⅳ. After cladding, using an asbestos blanket to wrap the workpiece for slow cooling.

[0012] Among them: when there are cracks in the journal of the heavy-duty universal joint cross shaft and the repair dimension is 2 mm, the specific steps of the laser cladding method are as follows: Ⅰ. Using a lathe to turn until all cracks are removed; Ⅱ. Using a heating tape to wrap for preheating, with a preheating temperature of 300°C and holding for 1 h; Ⅲ. Using a round spot optical head for laser cladding: the spot diameter is 5 mm, the cladding power is 3.5 KW, the scanning speed is 720 mm / min, and a total of two layers are cladded, with a single-layer cladding thickness of 1.5 mm; Ⅳ. After cladding, using an asbestos blanket to wrap the workpiece for slow cooling.

[0013] The principles and advantages of the cemented carbide powder of the present invention are as follows: I. The iron-based alloy is an iron-based self-fluxing alloy: 0.8-2% B and 1.0-1.8% Si mainly reduce the melting point of the alloy, form eutectics with low melting points, and at the same time form hard phases such as CrB, which improves the hardness and wear resistance of the alloy to a certain extent; II. The Cr element can refine the grains, the Ni element can promote the refinement of the structure, and the phases of the steel containing both Cr and Ni elements are all Fe-Cr-Ni solid solutions, FeC, and Cr3C2, which can refine the grains, thereby improving the impact resistance, and at the same time the increase in hardness also improves the impact resistance; Si can increase the elastic limit, yield strength, and yield ratio (σs / σb) of the steel, as well as the fatigue strength and fatigue ratio (σ-1 / σb), thereby improving the fatigue resistance; III. The carbon content of the alloy is extremely low, preventing intergranular corrosion, increasing the mechanical strength, and making it difficult for cracks and coating peeling to occur on the surface coating and matrix after being impacted.

[0014] The advantages of the cemented carbide powder and the laser cladding method for the wear-resistant layer of the heavy-duty universal cross shaft of the present invention are: 1. Laser cladding makes the wear-resistant alloy layer and the cross shaft matrix metallurgically bonded, with strong bonding force and not easy to fall off; at the same time, the heat input is small, and the thermal deformation of the shaft neck is small; 2. The carbon content of the alloy is extremely low, preventing intergranular corrosion, increasing the mechanical strength, and making it difficult for cracks and coating peeling to occur on the surface coating and matrix after being impacted; 3. Through the setting of the composition and the combination of reasonable percentages of each component of the alloy, the hardness, wear resistance, impact resistance, and fatigue resistance of the wear-resistant layer are all good, thereby extending the service life of the cross shaft and reducing the cost; 4. Through the combination of the alloy material and laser cladding, laser cladding can be used to repair the cross shaft with severe spalling with deep spalling and cracks, with a maximum repair depth of 2.0 mm, reducing the cost. Specific embodiments

[0015] The following further elaborates on the present invention in conjunction with specific embodiments.

[0016] Example 1

[0017] The percentage of the components of the cemented carbide powder for the wear-resistant layer of the heavy-duty universal cross shaft of the present invention is: 14-19% Cr, 1.0-2.1% Ni, 0.5-1.3% Mo, 1-2% B, 1-1.5% Si, <0.2% C, <0.7% Mn, and the balance is Fe; the particle size is 53-108 μm.

[0018] The preferred components of the cemented carbide material are 18% Cr, 1.8% Ni, 1.1% Mo, 1.5% B, 1.2% Si, <0.2% C, <0.6% Mn, and the balance is Fe.

[0019] The composition of the cemented carbide material is preferably 17% Cr, 1.8% Ni, 1.2% Mo, 1.5% B, 1.4% Si, <0.2% C, <0.5% Mn, and the balance is Fe.

[0020] The composition of the cemented carbide material is preferably 17.2% Cr, 1.6% Ni, 1.1% Mo, 1.3% B, 1.2% Si, <0.2% C, <0.5% Mn, and the balance is Fe.

[0021] The principle and advantages of the cemented carbide powder of the present invention are as follows: First, the iron-based alloy is an iron-based self-fluxing alloy: 0.8 - 2% B and 1.0 - 1.8% Si mainly reduce the melting point of the alloy, form a eutectic with a low melting point, and at the same time form hard phases such as CrB, which improves the hardness and wear resistance of the alloy to a certain extent; Second, the Cr element can refine the grains, the Ni element can promote the refinement of the structure, and the phases of the steel containing both Cr and Ni elements are all Fe-Cr-Ni solid solution, FeC, and Cr3C2, which can refine the grains, thereby improving the impact resistance, and at the same time the increase in hardness also improves the impact resistance; Si can increase the elastic limit, yield strength, and yield ratio (σs / σb) of the steel, as well as the fatigue strength and fatigue ratio (σ-1 / σb), thereby improving the fatigue resistance; Third, the carbon content of the alloy is extremely low, preventing intergranular corrosion, improving the mechanical strength, and making it difficult for cracks and coating peeling to occur on the surface coating and matrix after being impacted.

[0022] Example 2

[0023] The laser cladding method for the heavy-duty universal joint cross shaft of the present invention specifically comprises the following steps: treating the journal; preheating: 250°C - 300°C, holding for 1 h; laser cladding; slow cooling.

[0024] In the early manufacturing of the heavy-duty universal joint cross shaft: its surface is generally carburized and quenched, and the hardness is about 58 - 62 HRC. When laser cladding is performed on the surface of such a high-hardness material, high-temperature preheating is generally used, and the preheating temperature is generally 250 - 300°C.

[0025] After the laser cladding is completed, the journal is generally ground by a grinding machine to make its dimensions and surface roughness meet the requirements of the drawing.

[0026] Example 3

[0027] When the repair dimension of the journal of the heavy-duty universal joint cross shaft is 0.2 mm, the specific steps of the laser cladding method are as follows:

[0028] Ⅰ. Grind the spalled part of the journal to remove surface rust and oil, and make the spalled part smoothly transition to other positions;

[0029] Ⅱ. Use a heating tape to wrap for preheating, with a preheating temperature of 250°C and hold for 1 h;

[0030] III. Laser cladding is carried out using a round spot optical head: the spot diameter is 5 mm, the cladding power is 3.0 KW, the scanning speed is 720 mm / min, and the single-layer cladding thickness is 1.1 mm;

[0031] IV. After the cladding is completed, the workpiece is wrapped with asbestos quilts for slow cooling.

[0032] In step III: The chemical composition of the laser cladding cemented carbide material is 18% Cr, 1.8% Ni, 1.1% Mo, 1.5% B, 1.2% Si, <0.2% C, <0.6% Mn, and the balance is Fe.

[0033] Since the spalling defect of the cross shaft is small, it is more convenient to use a round spot optical head.

[0034] Example 4

[0035] When the repaired size of the journal of the heavy-duty universal cross shaft is 1.5 mm, the specific steps of the laser cladding method are as follows:

[0036] I. Grind the spalling part of the journal to remove surface rust and oil, and make the spalling part smoothly transition to other positions;

[0037] II. Preheat by wrapping with a heating tape, the preheating temperature is 300 °C, and keep warm for 1 h;

[0038] III. Laser cladding is carried out using a round spot optical head: the spot diameter is 5 mm, the cladding power is 3.2 KW, the scanning speed is 720 mm / min, a total of two layers are cladded, and the single-layer cladding thickness is 1.3 mm;

[0039] IV. After the cladding is completed, the workpiece is wrapped with asbestos quilts for slow cooling.

[0040] In step II: Since the repaired size is large and the single-layer cladding layer is relatively thick at 1.3 mm, the preheating temperature is the upper limit of 300 °C.

[0041] In step III: The chemical composition of the laser cladding cemented carbide material is 17% Cr, 1.8% Ni, 1.2% Mo, 1.5% B, 1.4% Si, <0.2% C, <0.5% Mn, and the balance is Fe.

[0042] Example 5

[0043] When there are cracks in the journal of the heavy-duty universal cross shaft and the repaired size is 2 mm, the specific steps of the laser cladding method are as follows:

[0044] I. Use a lathe to turn until all the cracks are removed;

[0045] II. Preheat by wrapping with a heating tape, the preheating temperature is 300 °C, and keep warm for 1 h;

[0046] Ⅲ. Laser cladding is carried out using a round spot optical head: the spot diameter is 5 mm, the cladding power is 3.5 KW, the scanning speed is 720 mm / min, and a total of two layers are cladded with a single-layer cladding thickness of 1.5 mm;

[0047] Ⅳ. After the cladding is completed, the workpiece is wrapped with asbestos blankets for slow cooling.

[0048] In step Ⅱ: Since the repair size is large and the single-layer cladding layer is relatively thick at 1.5 mm, the preheating temperature is the upper limit of 300 °C.

[0049] In step Ⅲ: The chemical composition of the laser cladding cemented carbide material is 17.2% Cr, 1.6% Ni, 1.1% Mo, 1.3% B, 1.2% Si, <0.2% C, <0.5% Mn, and the balance is Fe.

[0050] The advantages of the alloy material and the laser cladding method for the wear-resistant layer of the heavy-duty universal cross shaft of the present invention are as follows: 1. Laser cladding makes the wear-resistant alloy layer and the cross shaft matrix metallurgically bonded, with strong bonding force and not easy to fall off; at the same time, the heat input is small and the thermal deformation of the shaft neck is small; 2. The carbon content of the alloy is extremely low, preventing intergranular corrosion, improving the mechanical strength, and the surface coating and matrix are not prone to cracks and coating spalling problems after being impacted; 3. Through the setting of the composition and the combination of reasonable percentages of each component, the hardness, wear resistance, impact resistance, and fatigue resistance of the wear-resistant layer are all good; 4. Through the combination of the alloy material and laser cladding, laser cladding can be used to repair the cross shaft with severe spalling with deep spalling and cracks, with a maximum repair depth of 2.0 mm, reducing the cost.

Claims

1. Cemented carbide powder for wear-resistant layer of overloaded universal cross shaft, characterized in that: The percentages of its components are: 14-19% Cr, 1.0-2.1% Ni, 0.5-1.3% Mo, 1-2% B, 1-1.5% Si, <0.2% C, <0.7% Mn, and the balance is Fe; the particle size is 53-108 μm.

2. The cemented carbide powder according to claim 1, characterized in that: Its components are preferably 18% Cr, 1.8% Ni, 1.1% Mo, 1.5% B, 1.2% Si, <0.2% C, <0.6% Mn, and the balance is Fe.

3. The cemented carbide powder according to claim 1, characterized in that: Its components are preferably 17% Cr, 1.8% Ni, 1.2% Mo, 1.5% B, 1.4% Si, <0.2% C, <0.5% Mn, and the balance is Fe.

4. The cemented carbide powder according to claim 1, characterized in that: Its components are preferably 17.2% Cr, 1.6% Ni, 1.1% Mo, 1.3% B, 1.2% Si, <0.2% C, <0.5% Mn, and the balance is Fe.

5. Laser cladding method for wear-resistant layer of heavy-duty universal joint cross shaft. The specific steps are as follows: process the journal; preheat: 250°C - 300°C, keep warm for 1 h; laser cladding; slow cooling.

6. The laser cladding method according to claim 5, characterized in that: When the repaired size of the journal of the heavy-duty universal joint cross shaft is 0.2 mm, the specific steps are as follows: Ⅰ. Grind the spalled part of the journal to remove surface rust and oil, and make the spalled part smoothly transition with other positions; Ⅱ. Wrap with a heating tape for preheating, the preheating temperature is 250°C, keep warm for 1 h; Ⅲ. Use a round spot optical head for laser cladding: the spot diameter is 5 mm, the cladding power is 3.0 KW, the scanning speed is 720 mm / min, and the single-layer cladding thickness is 1.1 mm; Ⅳ. After cladding, wrap the workpiece with asbestos quilt for slow cooling.

7. The laser cladding method according to claim 5, characterized in that: When the repaired size of the journal of the heavy-duty universal joint cross shaft is 1.5 mm, the specific steps are as follows: Ⅰ. Grind the spalled part of the journal to remove surface rust and oil, and make the spalled part smoothly transition with other positions; Ⅱ. Wrap with a heating tape for preheating, the preheating temperature is 300°C, keep warm for 1 h; Ⅲ. Use a round spot optical head for laser cladding: the spot diameter is 5 mm, the cladding power is 3.2 KW, the scanning speed is 720 mm / min, and a total of two layers are cladded, with a single-layer cladding thickness of 1.3 mm; Ⅳ. After cladding, wrap the workpiece with asbestos quilt for slow cooling.

8. The laser cladding method according to claim 5, characterized in that: When there are cracks in the journal of the heavy-duty universal joint cross shaft and the repaired size is 2 mm, the specific steps of the laser cladding method are as follows: Ⅰ. Use a lathe to turn until all cracks are removed; Ⅱ. Wrap with a heating tape for preheating, the preheating temperature is 300°C, keep warm for 1 h; Ⅲ. Use a round spot optical head for laser cladding: the spot diameter is 5 mm, the cladding power is 3.5 KW, the scanning speed is 720 mm / min, and a total of two layers are cladded, with a single-layer cladding thickness of 1.5 mm; Ⅳ. After cladding, wrap the workpiece with asbestos quilt for slow cooling.