A multi-directional asynchronous loading upsetting forging method for special-shaped shaft components

Abstract

The present invention provides a multi-directional asynchronous loading upsetting forging method for a special-shaped shaft component, comprising the following steps: blanking; heating, heating the blank obtained in step 1 to 1000°C and holding the temperature for 40±10 minutes; placing the heated blank into a mold, closing the mold, using a loading device to perform asynchronous loading upsetting forging on the blank according to a set loading curve, and placing the formed component in air for cooling; wherein the loading device includes an axial left punch, a radial punch, and an axial right punch located at the upper portion of the mold cavity, with a push rod provided below the radial punch. The present invention can form large-sized, complex special-shaped shaft components using a simple process. The resulting components have high mechanical properties and good internal quality. In particular, the problem of low grain size in the center portion of special-shaped shaft components prepared by existing methods is solved. The method also has the advantages of high material utilization, short production cycle, low production cost, and ease of operation.

Description

Technical Field

[0001] The invention belongs to the technical field of precision plastic forming, and in particular relates to a multi-directional asynchronous loading upsetting forging method for a special-shaped shaft component. Background Art

[0002] Special-shaped shaft (complex) components are mostly used as the main load-bearing and important parts of equipment or instruments. They are subject to complex stresses in various environments and have very high performance requirements. The materials involve various types of structural steel, aluminum alloys and other fields. Its traditional preparation method is generally to use large-diameter bar machining, but this method has huge material waste, extremely low efficiency, poor component performance, and cannot be mass-produced for large-sized complex components; another way is to use a horizontal extruder for extrusion, but this method is generally for rotating regular components. For complex irregular components, it is necessary to first use a horizontal extruder to make the blank, and then use a die forging process for multiple forming steps to prepare it. The process is long, the process is complex, the equipment requirements are high, the key points are difficult to control, the efficiency is low, and the manufacturing cycle is long.

[0003] For large-sized (length greater than 1300mm or diameter greater than 200mm) special-shaped shaft-like complex components (such as 40CrNiMo steel special-shaped shafts with two non-standard annular protrusions arranged at intervals, a connecting section between the two non-standard annular protrusions, the axis of the connecting section deviates from the axis of the main body of the special-shaped shaft component, and the two axes are parallel), usually only the casting process can be used. However, in the actual production process, considering the problem of low performance of cast components, the blanks are generally first made through the casting process, and then forged with a large-tonnage die forging hammer to forge the approximate shape, and finally completed by machining. However, due to the small amount of plastic deformation of the parts made by this process, their internal structure still retains the cast structure (the internal grain size is usually level 5, which just meets the qualified requirements), and the performance of the resulting components is still not ideal. Summary of the Invention

[0004] The object of the present invention is to provide a multi-directional asynchronous loading upsetting forging method for a special-shaped shaft component, which can at least solve the problem of low grain size grade in the central part of the special-shaped shaft component prepared by the existing method.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solution.

[0006] A multi-directional asynchronous loading upsetting forging method for a special-shaped shaft component, characterized in that the steps include:

[0007] Step 1: Cutting the structural steel bar into blanks;

[0008] Step 2: heating the blank obtained in step 1 to 1000° C. and keeping the temperature for 40±10 minutes;

[0009] Step 3: Place the heated blank into the mold, close the mold, and use a loading device to perform asynchronous loading and upsetting on the blank according to a set loading curve, and place the formed component in the air to cool;

[0010] The loading device includes an axial left punch, a radial punch and an axial right punch located at the upper part of the mold cavity, and a push rod is provided below the radial punch;

[0011] The loading curve satisfies the following requirements: in the first 0-2 seconds, the loading speeds of the axial left punch and the axial right punch are respectively increased from zero to 6 mm / s, and then maintained at a loading speed of 6 mm / s for 9-10 seconds. In the next 2 seconds, the loading speeds of the two punches are reduced to zero; in the second 2-4 seconds, the loading speed of the radial punch is increased from zero to 2 mm / s; in the fourth to sixth seconds, the loading speed of the radial punch is maintained at 2 mm / s; in the sixth to seventh seconds, the loading speed of the radial punch is increased from 2 mm / s to 4 mm / s; in the seventh to ninth seconds, the loading speed of the radial punch is maintained at 4 mm / s; in the ninth to tenth seconds, the loading speed of the radial punch is increased from 4 mm / s to 5 mm / s, and then maintained at a loading speed of 5 mm / s for 2 seconds, and then the loading speed of the radial punch is reduced to zero.

[0012] Furthermore, in step 3, the component formed by asynchronous loading upsetting is first held at pressure for 30±5 seconds and then placed in air for cooling.

[0013] As a preferred solution, the loading curve satisfies the following requirements: in the 0th to 1st second, the loading speeds of the axial left punch and the axial right punch are respectively increased from zero to 6 mm / s, and then maintained at a loading speed of 6 mm / s for 9 seconds. In the next 1 second, the loading speeds of the two punches are reduced to zero; in the 3rd to 4th seconds, the loading speed of the radial punch is increased from zero to 2 mm / s; in the 4th to 6th seconds, the loading speed of the radial punch is maintained at 2 mm / s; in the 6th to 7th seconds, the loading speed of the radial punch is increased from 2 mm / s to 4 mm / s; in the 7th to 9th seconds, the loading speed of the radial punch is maintained at 4 mm / s; in the 9th to 10th seconds, the loading speed of the radial punch is increased from 4 mm / s to 5 mm / s; in the 11th to 12th seconds, the loading speed of the radial punch is reduced to zero.

[0014] In order to further improve the forming quality of special-shaped shaft components, the axial left punch and the axial right punch both use punches with electric heating wires, and the temperature of the punches is maintained at 400±10℃ during loading.

[0015] In the present invention, the special-shaped shaft component has two non-standard annular protrusions arranged at intervals, a connecting section is provided between the two non-standard annular protrusions, the axis of the connecting section deviates from the axis of the special-shaped shaft component, and the two axes are parallel.

[0016] As another preferred solution, the loading curve satisfies:

[0017] In the first 0-1 seconds, the loading speed of the center punch is increased from zero to 6 mm / s, and then maintained at a loading speed of 6 mm / s for 1 second. In the next 1 second, the loading speeds of the two punches are reduced to zero. Then, in the next 1 second, the loading speeds of the center punch are further increased from zero to 6 mm / s, and then maintained at a loading speed of 6 mm / s for 6 seconds. In the next 1 second, the loading speeds of the two center punches are reduced to zero.

[0018] In the first 1-2 seconds, the loading speeds of the axial left punch and the axial right punch were increased from zero to 6 mm / s, and then maintained at a loading speed of 6 mm / s for 8 seconds. In the next 1 second, the loading speeds of the two punches were reduced to zero;

[0019] In the 3rd to 4th seconds, the loading speed of the radial punch increases from zero to 2 mm / s; in the 4th to 6th seconds, the loading speed of the radial punch is maintained at 2 mm / s; in the 6th to 7th seconds, the loading speed of the radial punch increases from 2 mm / s to 4 mm / s; in the 7th to 9th seconds, the loading speed of the radial punch is maintained at 4 mm / s; in the 9th to 10th seconds, the loading speed of the radial punch increases from 4 mm / s to 5 mm / s; in the 11th to 12th seconds, the loading speed of the radial punch is reduced to zero.

[0020] Beneficial effects: The present invention can form large-sized special-shaped shaft-like complex components with a simple process. The components produced have high mechanical properties and good internal quality. In particular, it solves the problem of low grain size in the central part of special-shaped shaft-like components prepared by existing methods. It also has the advantages of high material utilization, short production cycle, low production cost, and easy operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the special-shaped shaft component prepared in Example 1 (main direction and side view);

[0022] Figure 2 This is a schematic diagram of the asynchronous loading route in Example 1;

[0023] Figure 3 This is a schematic diagram of the state of preparing the special-shaped shaft component in Example 1;

[0024] Figure 4 This is a schematic diagram of the state of preparing the special-shaped shaft component in Example 2;

[0025] Figure 5 This is a schematic diagram of the asynchronous loading route in Example 2;

[0026] Figure 6 This is a schematic diagram of the special-shaped shaft component prepared in Example 2. Its shape is the same as the special-shaped shaft component in Example 1, but the size is different. DETAILED DESCRIPTION

[0027] The following embodiments are only intended to help understand the principles and core concepts of the present invention and are not intended to limit the scope of protection of the present invention. It should be noted that, for those skilled in the art, improvements made to the present invention without departing from the principles of the present invention also fall within the scope of protection of the claims of the present invention.

[0028] Example 1

[0029] A multi-directional asynchronous loading upsetting method for a long shaft (heteromorphic shaft) component, wherein the heteromorphic shaft component is Figure 1 As shown, there are two non-standard annular protrusions arranged at intervals, and a connecting section is provided between the two non-standard annular protrusions. The axis of the connecting section deviates from the axis of the main body of the special-shaped shaft component, and the two axes are parallel.

[0030] The steps of the method include:

[0031] Step 1, cutting, 40CrNiMo structural steel bar sawn into of blanks;

[0032] Step 2: heating the blank obtained in step 1 to 1000° C. and keeping the temperature for 40 minutes;

[0033] Step 3: Place the heated billet into the mold, close the mold, and use a loading device to perform asynchronous loading upsetting on the billet according to the set loading curve. After the asynchronous loading upsetting, the component is first held at pressure for 30±5 seconds and then placed in air to cool.

[0034] The loading device includes an axial left punch 1, a radial punch 3 and an axial right punch 5 located at the upper part of the mold cavity, and a push rod 4 is provided below the radial punch 3; during the loading process, Figure 3 As shown, number 2 represents the blank, and the arrow represents the loading direction. The middle area of ​​the blank passes through the middle holes of the axial left punch 1 and the axial right punch 5. The axial left punch and the axial right punch are both punches with electric heating wires. The temperature of the punches is always maintained at 400±5℃ during the loading process.

[0035] Among them, the loading curve / route is as follows Figure 2As shown in FIG, specifically: in the 0th to 1st second, the loading speeds of the axial left punch and the axial right punch are respectively increased from zero to 6 mm / s, and then maintained at a loading speed of 6 mm / s for 9 seconds. In the next 1 second, the loading speeds of the two punches are reduced to zero; in the 3rd to 4th seconds, the loading speed of the radial punch is increased from zero to 2 mm / s; in the 4th to 6th seconds, the loading speed of the radial punch is maintained at 2 mm / s; in the 6th to 7th seconds, the loading speed of the radial punch is increased from 2 mm / s to 4 mm / s; in the 7th to 9th seconds, the loading speed of the radial punch is maintained at 4 mm / s; in the 9th to 10th seconds, the loading speed of the radial punch is increased from 4 mm / s to 5 mm / s; in the 11th to 12th seconds, the loading speed of the radial punch is reduced to zero.

[0036] Example 2

[0037] A multi-directional asynchronous loading upsetting method for a short shaft (heteromorphic shaft) component, wherein the heteromorphic shaft component is Figure 6 As shown, there are two non-standard annular protrusions arranged at intervals, and there is a connecting section between the two non-standard annular protrusions. The axis of the connecting section deviates from the axis of the main body of the shaft-shaped component, and the two axes are parallel

[0038] The steps of the method include:

[0039] Step 1, cutting, 40CrNiMo structural steel bar sawn into of blanks;

[0040] Step 2: heating the blank obtained in step 1 to 1000° C. and keeping the temperature for 45 minutes;

[0041] Step 3: Place the heated billet into the mold, close the mold, and use a loading device to perform asynchronous loading upsetting on the billet according to the set loading curve. After the asynchronous loading upsetting, the component is first held at pressure for 30±5 seconds and then placed in air to cool.

[0042] The loading device includes an axial left punch 1 (referred to as the left punch), a radial punch 3 (also referred to as the upper punch) and an axial right punch 5 (referred to as the right punch) located at the upper part of the mold cavity. A center punch 6 is provided in the middle of the axial left punch 1 and the axial right punch 5, respectively, and a push rod 4 is provided below the radial punch 3. During the loading process, Figure 4 As shown, number 2 represents the blank, the arrow represents the loading direction, the left end of the blank is completely located in the cavity of the axial left punch 1, and the right end of the blank is completely located in the cavity of the axial right punch 5; the axial left punch 1 and the axial right punch 5 are both punches with electric heating wires, and the temperature of the punches is always maintained at 400±5℃ during the loading process;

[0043] Among them, the loading curve / route is as follows Figure 5As shown, specifically:

[0044] In the first 0-1 seconds, the loading speed of the center punch is increased from zero to 6 mm / s, and then maintained at a loading speed of 6 mm / s for 1 second. In the next 1 second, the loading speeds of the two punches are reduced to zero. Then, in the next 1 second, the loading speeds of the center punch are further increased from zero to 6 mm / s, and then maintained at a loading speed of 6 mm / s for 6 seconds. In the next 1 second, the loading speeds of the two center punches are reduced to zero.

[0045] In the first 1-2 seconds, the loading speeds of the axial left punch and the axial right punch were increased from zero to 6 mm / s, and then maintained at a loading speed of 6 mm / s for 8 seconds. In the next 1 second, the loading speeds of the two punches were reduced to zero;

[0046] In the 3rd to 4th seconds, the loading speed of the radial punch increases from zero to 2 mm / s; in the 4th to 6th seconds, the loading speed of the radial punch is maintained at 2 mm / s; in the 6th to 7th seconds, the loading speed of the radial punch increases from 2 mm / s to 4 mm / s; in the 7th to 9th seconds, the loading speed of the radial punch is maintained at 4 mm / s; in the 9th to 10th seconds, the loading speed of the radial punch increases from 4 mm / s to 5 mm / s; in the 11th to 12th seconds, the loading speed of the radial punch is reduced to zero.

[0047] Comparative Example 1: The aforementioned 40CrNiMo special-shaped shaft component of the same material and the same specifications was prepared by conventional / conventional forging process.

[0048] Comparative Example 2: The aforementioned 40CrNiMo special-shaped shaft component of the same material and the same specifications was prepared using a traditional / conventional forging process.

[0049] The special-shaped shaft components obtained in Example 1 and Example 2 were cleaned and sandblasted before being measured. The dimensional measurement results are shown in Table 1. The measurement positions are combined with the Figure 1 As shown; the conventional hot die forging process (Comparative Example 1, Comparative Example 2) was used to prepare special-shaped shaft components of the same specifications, and their dimensions are shown in Table 1.

[0050] Table 1 Dimensional measurement results of Example 1 and Comparative Example

[0051]

[0052] When the scheme in Example 1 is used to prepare the 40CrNiMo special-shaped shaft component, the upsetting forging force of the loading equipment is measured to be 1200KN. When the scheme in Example 2 is used to prepare the 40CrNiMo special-shaped shaft component, the upsetting forging force of the loading equipment is measured to be 1680KN. During the loading process, the mold cavity is fully filled and easy to load. In comparison with Example 1, the die forging force is measured to be 2000KN, and in comparison with Example 2, the die forging force is measured to be 2500KN, and there is still a situation where the mold is not fully filled.

[0053] The grain size of the special-shaped shaft component obtained in Example 1 is not less than level 8 (wherein, the E part is level 8, the F part is level 8.5, and the G part is level 8), which meets the technical requirements of high-precision forgings; while the average grain size of the special-shaped shaft component obtained in Comparative Example 1 is level 5.5 (wherein, the E part is level 6, the F part is level 5.5, and the G part is level 5).

[0054] The grain size of the special-shaped shaft component obtained in Example 2 was no less than grade 8.5 (with grade 8.5 for part E, grade 9 for part F, and grade 9 for part G), meeting the technical requirements for high-precision forgings. In contrast, the average grain size of the special-shaped shaft component obtained in Comparative Example 2 was grade 5 (with grade 5 for part E, grade 5 for part F, and grade 5 for part G). In contrast, the present invention enables the formation of defect-free special-shaped shaft components through a single heat treatment, with low forming forces during the loading process, significantly improving the internal structure and pass rate of the resulting special-shaped shaft components.

[0055] By adopting the scheme of the present invention, complex and difficult-to-deform shaft-like components can be formed smoothly and quickly. The internal structure and quality of the obtained components are good, the forming force during loading is small, and it has the advantages of high material utilization and high processing efficiency. By adopting the scheme of the present invention, the processing cycle of complex special-shaped shaft-like components can be greatly shortened, and the production process can be simplified (the processing cycle of the scheme in Example 1 is about 4 hours, and the processing cycle in Comparative Example 1 is about 16 hours). It is highly operational and low in cost (the total processing and manufacturing costs of adopting the schemes in Example 1 and Example 2 are respectively about 500 yuan, which is suitable for large-scale production; while the total processing and manufacturing costs of adopting the schemes in Comparative Example 1 and Comparative Example 2 are respectively about 2,400 yuan).

Claims

1. A multi-directional asynchronous loading upsetting forging method for a special-shaped shaft component, characterized in that the steps include: Step 1: Cutting the structural steel bar into blanks; Step 2: heating the blank obtained in step 1 to 1000° C. and keeping the temperature for 40±10 minutes; Step 3: Place the heated blank into the mold, close the mold, and use a loading device to asynchronously load and form the blank according to a set loading curve, and place the formed component in the air to cool; The loading device includes an axial left punch, a radial punch, and an axial right punch located at the upper part of the die cavity. A center punch is provided in the middle of each of the axial left punch and the axial right punch, and a push rod is provided below the radial punch. During the loading process, the left end of the blank is completely located in the cavity of the axial left punch, and the right end of the blank is completely located in the cavity of the axial right punch. Both the axial left punch and the axial right punch are punches with electric heating wires, and the temperature of the punches is always maintained at 400±5℃ during the loading process. The loading curve satisfies: In the first 0-1 seconds, the loading speed of the center punch is increased from zero to 6 mm / s, and then maintained at a loading speed of 6 mm / s for 1 second. In the next 1 second, the loading speeds of the two punches are reduced to zero. Then, in the next 1 second, the loading speeds of the center punch are further increased from zero to 6 mm / s, and then maintained at a loading speed of 6 mm / s for 6 seconds. In the next 1 second, the loading speeds of the two center punches are reduced to zero. In the first 1-2 seconds, the loading speeds of the axial left punch and the axial right punch were increased from zero to 6 mm / s, and then maintained at a loading speed of 6 mm / s for 8 seconds. In the next 1 second, the loading speeds of the two punches were reduced to zero; In the 3rd to 4th seconds, the loading speed of the radial punch is increased from zero to 2 mm / s; in the 4th to 6th seconds, the loading speed of the radial punch is maintained at 2 mm / s; in the 6th to 7th seconds, the loading speed of the radial punch is increased from 2 mm / s to 4 mm / s; in the 7th to 9th seconds, the loading speed of the radial punch is maintained at 4 mm / s; in the 9th to 10th seconds, the loading speed of the radial punch is increased from 4 mm / s to 5 mm / s; in the 11th to 12th seconds, the loading speed of the radial punch is reduced to zero; The special-shaped shaft component is a 40CrNiMo special-shaped shaft component, having two non-standard annular protrusions arranged at intervals, a connecting section between the two non-standard annular protrusions, an axis of the connecting section deviates from the axis of the special-shaped shaft component, and the two axes are parallel.

2. The multi-directional asynchronous loading upsetting method according to claim 1, characterized in that: In step 3, the component formed by asynchronous loading is first held under pressure for 30±5 seconds and then placed in air for cooling.

3. The multi-directional asynchronous loading upsetting method according to any one of claims 1 to 2, characterized in that: The axial left punch and the axial right punch both use punches with electric heating wires, and the temperature of the punches is maintained at 400±10°C during the loading process.

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