High-speed extrusion forming process for GH6159 spline bolt matched with water-cooling constant-temperature mold frame

Abstract

The invention discloses a high-speed extrusion forming process for a GH6159 spline bolt matched with a water-cooling constant-temperature die frame. The high-speed extrusion forming process comprises the steps that a constant-temperature environment is constructed in a contact area of a hot upsetting die and the upper part of the die frame, and extrusion forming is conducted on the head of a blank rod body. As the temperature of the contact area of the hot upsetting die and the upper part of the die frame is within a constant range of 20-90 DEG C, the influence of thermal expansion and cold contraction caused by severe temperature change can be avoided, and the hot upsetting die and the upper part of the die frame are matched and seized, so that the hot upsetting die and the upper part of the die frame are convenient to detach, separate and replace; the problems that when the temperature of the contact area of the hot upsetting die and the die frame rises due to heat, matching seizure occurs, and disassembly, separation and replacement cannot be conducted are solved.

Description

Technical Field

[0001] This invention relates to a high-speed extrusion molding process for GH6159 spline bolts adapted to a water-cooled constant temperature mold frame, belonging to the field of bolt forming technology. Background Technology

[0002] When the plate screw head of the GH6159 spline bolt is extruded using a hot upsetting die (see Chinese patent application publication number CN119819857A), the hot upsetting die, mounted on the upper part of the die set, is moved downwards. Because the billet rod head carries a large amount of heat after heating, this heat causes the temperature of the area where the hot upsetting die contacts the die set to rise. This drastic temperature change leads to thermal expansion and contraction, which can easily cause the hot upsetting die to seize up with the die set, making it impossible to remove and replace the hot upsetting die from the upper part of the die set. Summary of the Invention

[0003] To solve the above technical problems, the present invention provides a high-speed extrusion molding process for GH6159 spline bolts adapted to a water-cooled constant temperature mold frame.

[0004] The present invention is achieved through the following technical solutions.

[0005] The present invention provides a high-speed extrusion molding process for GH6159 spline bolts adapted to a water-cooled constant temperature mold frame, comprising: constructing a constant temperature environment in the upper contact area between the hot upsetting die and the mold frame, and performing a high-speed molding process for extruding the head of the blank rod.

[0006] The high-speed forming steps are as follows: the spiral electric heating coil is energized to induction heat the head of the blank rod with electromagnetic eddy current; the rod part of the blank rod is installed in the lower part of the mold frame, and the hot upsetting die is supported and installed in the upper part of the mold frame by a support plate; the upper part of the mold frame moves down together with the hot upsetting die to extrude and form the head of the blank rod; cooling water flows through the cooling water channel in the upper part of the mold frame to exchange heat and control the temperature, ensuring that the temperature of the area in contact between the hot upsetting die and the upper part of the mold frame is constant; after the head of the blank rod is filled and extruded into a twelve-spline structure in the hot upsetting die, it is cooled by the cooling water channel in the upper part of the mold frame.

[0007] The head of the blank rod is heated to 870℃~980℃, and the heating rate is controlled at 0.8 min / mm~1.2 min / mm.

[0008] The forming rate for extruding the head is 300 mm / s to 500 mm / s.

[0009] The temperature of the area where the hot forging die contacts the upper part of the die frame is constant at 20°C to 90°C.

[0010] The cooling rate of the head of the billet rod in the hot upsetting die is 50°C / s to 150°C / s.

[0011] Before the high-speed forming step, a lubrication step is also included; the lubrication step is a spray lubrication system that sprays lubrication onto the hot upsetting mold in the upper part of the mold frame.

[0012] The spray lubrication system includes a high-pressure tank for storing nitrogen nitride and a nozzle connected to the high-pressure tank via an electrically controlled valve, which is controlled by an electronic control system; the hot upsetting die is made of silicon nitride ultrahard ceramic.

[0013] When the head of the billet rod is heated, the rod part of the billet rod is inside the support sleeve. The support sleeve is provided with a water flow cooling space, through which cooling water is introduced to cool the rod part.

[0014] The beneficial effects of this invention are as follows: Since the temperature of the area in contact between the hot upsetting die and the upper part of the die frame is in a constant range of 20 to 90°C, the effects of thermal expansion and contraction caused by drastic temperature changes can be avoided. Furthermore, the hot upsetting die and the upper part of the die frame are locked together, which facilitates disassembly and replacement of the hot upsetting die and the upper part of the die frame. This solves the problem that when the temperature of the area in contact between the hot upsetting die and the die frame rises due to heat, the engagement becomes locked, making disassembly and replacement impossible. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the GH6159 spline bolt structure with twelve splines of the present invention; Figure 2 This is a cross-sectional schematic diagram of the spiral electric heating coil and the blank rod of the present invention during heating distribution; Figure 3 This is a cross-sectional schematic diagram of the hot forging die of the present invention; Figure 4 This is a schematic diagram of the distribution of the spray lubrication system of the present invention; Figure 5 This is a cross-sectional schematic diagram of the upper and lower parts of the mold frame when they are closed. Figure 6 This is a vertical cross-sectional schematic diagram of the upper part of the mold frame, the lower part of the mold frame, the hot upsetting mold, and the blank rod of the present invention; In the diagram: 1-Spray lubrication system; 11-Nitrogen phosphate high-pressure tank; 12-Nozzle; 13-Electrical control system; 2-Upper part of mold frame; 21-Lower part of mold frame; 22-Plate; 23-Water cooling channel; 24-Temperature control system; 3-Hot forging die; 31-Die sleeve; 32-Die core; 33-Cavity spline area; 4-Spiral electric heating coil; 5-Blank rod body; 51-Head; 52-Rod section; 53-Support sleeve; 54-Water flow cooling space. Detailed Implementation

[0016] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0017] See Figures 1 to 6 As shown.

[0018] This application discloses a high-speed extrusion molding process for GH6159 spline bolts adapted to a water-cooled constant temperature mold frame, comprising the following steps.

[0019] Step 1, Material Preparation: Procurement of materials according to specific requirements to improve the quality of material procurement and strictly control the composition and surface condition of incoming materials; Step 2, material cutting: Control the dimensions and appearance according to the process, and require the end face to be flat. This process involves fine control of the rounding dimensions. Step 3, Lubrication: A spray lubrication system 1 is used to spray lubricate the hot upsetting mold 3 in the upper part 2 of the mold frame. The spray lubricant is BN spray lubricant. The spray lubrication system 1 includes a high-pressure tank 11 for storing BN and a nozzle 12 connected to the high-pressure tank 11 via an electrically controlled valve. The electrically controlled valve is controlled by an electrically controlled system 13. The electrically controlled system 13 precisely controls the degree of lubrication through a PLC program to ensure that the lubricating layer sprayed from the nozzle 12 is evenly distributed in the cavity of the hot upsetting mold 3, which is beneficial to the smooth flow of material during the plastic forming process. The hot upsetting mold 3 is made of silicon nitride ultra-hard ceramic with a mold hardness of HRA91~94.

[0020] The BN spray lubricant is composed of (mass fraction): BN (25%–40%), deionized water (40%–60%), and polyethylene glycol dispersant (2%–4%). Due to the hexagonal structure and high-temperature resistance of BN, it forms a lubricating layer on the mold. During high-speed molding, it reduces the coefficient of friction between the material and the mold, which is beneficial for the flow and filling of metal materials and can effectively improve the fullness of the twelve splines. Furthermore, the BN-containing lubricant can be quickly dissolved by acid in the subsequent cleaning process, and the boron nitride powder is washed off with the acid, resulting in no environmental pollution and low cleaning costs.

[0021] Step 4, High-Speed ​​Forming: The spiral electric heating coil 4 is energized to induction heat the head 51 of the blank rod 5 to 870℃~980℃ using electromagnetic eddy current, with the heating rate controlled at 0.8 min / mm~1.2 min / mm. The rod portion 52 of the blank rod 5 is installed on the lower part 21 of the mold frame, and the hot upsetting die 3 is supported and installed in the upper part 2 of the mold frame by the support plate 22. The hot upsetting die 3 adopts a segmented combination structure, changing the spline structure to 6~12 segments, which are then combined together by hot pressing. The upper part 2 of the mold frame moves down with the hot upsetting die 3 to extrude and form the head 51 of the blank rod 5, with a forming rate of 300~500mm / s. This high-speed forming process is conducive to the rapid flow of material and filling of the cavity. During this process, cooling water flows through the cooling water channel 23 in the upper part 2 of the mold frame to exchange heat and control the temperature, ensuring that the temperature of the area in contact between the hot upsetting die 3 and the upper part 2 of the mold frame is within a constant range of 20~90℃. The flow of cooling water in the cooling water channel 23 is controlled by the temperature control system 24, which can be composed of a pump, solenoid valve, and PLC system. After the head 51 of the billet rod 5 is filled and extruded into a twelve-spline structure in the hot upsetting mold 3, the cooling rate is controlled by the cooling water channel 23 in the upper part 2 of the mold frame. The cooling rate is 50℃ / s to 150℃ / s, which helps to maintain the twisted shape and prevents the dimensions from deforming due to cooling stress.

[0022] Since the temperature of the area where the hot upsetting die 3 contacts the upper part 2 of the die frame is in a constant range of 20 to 90°C, it can avoid the influence of thermal expansion and contraction. The hot upsetting die 3 and the upper part 2 of the die frame are locked together, which makes it easy to disassemble and replace the hot upsetting die 3 and the upper part 2 of the die frame. This solves the problem that when the temperature of the area where the hot upsetting die contacts the die frame rises due to heat, the fit will lock together and it will be impossible to disassemble and replace it.

[0023] When the head 51 of the billet rod 5 is heated, the rod portion 52 of the billet rod 5 is located inside the support sleeve 53. The support sleeve 53 is provided with a water flow cooling space 54. Cooling water is introduced into the water flow cooling space 54 to cool the rod portion 52, so as to avoid the rod portion 52 from heating up too quickly, which would weaken the original strengthening effect of the material and result in insufficient final strength after forming.

[0024] The hot forging mold 3 is composed of a mold sleeve 31, a mold core 32 and a cavity spline region 33 on the mold core 32, and the twelve spline structure on the head 51 is filled and formed in the cavity spline region 33.

Claims

1. A high-speed extrusion molding process for GH6159 spline bolts adapted to a water-cooled constant-temperature mold frame, characterized in that, include: A high-speed forming process in which a constant temperature environment is created in the contact area between the hot forging die (3) and the upper part (2) of the die frame, and the head (51) of the blank rod (5) is extruded and formed.

2. The high-speed extrusion molding process for GH6159 spline bolts adapted to a water-cooled constant-temperature mold frame as described in claim 1, characterized in that, The high-speed forming steps are as follows: the spiral electric heating coil (4) is energized to induction heat the head (51) of the blank rod (5) with electromagnetic eddy current; the rod part (52) of the blank rod (5) is installed on the lower part (21) of the mold frame, and the hot upsetting mold (3) is supported and installed in the upper part (2) of the mold frame by the support plate (22); the upper part (2) of the mold frame moves down together with the hot upsetting mold (3) to extrude and form the head (51) of the blank rod (5); the cooling water flows through the cooling water channel (23) in the upper part (2) of the mold frame to exchange heat and control the temperature, so as to ensure that the temperature of the area in contact between the hot upsetting mold (3) and the upper part (2) of the mold frame is constant; after the head (51) of the blank rod (5) is filled and extruded into a twelve-spindle structure in the hot upsetting mold (3), the cooling is controlled by the cooling water channel (23) in the upper part (2) of the mold frame.

3. The high-speed extrusion molding process for GH6159 spline bolts adapted to a water-cooled constant-temperature mold frame as described in claim 2, characterized in that: The head (51) of the blank rod (5) is heated to 870℃~980℃, and the heating rate is controlled at 0.8 min / mm~1.2 min / mm.

4. The high-speed extrusion molding process for GH6159 spline bolts adapted to a water-cooled constant-temperature mold frame as described in claim 2, characterized in that: The forming rate of the head (51) being extruded is 300 mm / s to 500 mm / s.

5. The high-speed extrusion molding process for GH6159 spline bolts adapted to a water-cooled constant-temperature mold frame as described in claim 2, characterized in that: The temperature of the area where the hot forging die (3) contacts the upper part (2) of the die frame is constant at 20°C to 90°C.

6. The high-speed extrusion molding process for GH6159 spline bolts adapted to a water-cooled constant-temperature mold frame as described in claim 2, characterized in that: The cooling rate of the head (51) of the blank rod (5) in the hot upsetting mold (3) is 50°C / s to 150°C / s.

7. The high-speed extrusion molding process for GH6159 spline bolts adapted to a water-cooled constant-temperature mold frame as described in claim 2, characterized in that: Before the high-speed forming step, a lubrication step is also included; the lubrication step is that the spray lubrication system (1) sprays lubrication onto the hot upsetting mold (3) in the upper part (2) of the mold frame.

8. The high-speed extrusion molding process for GH6159 spline bolts adapted to a water-cooled constant-temperature mold frame as described in claim 7, characterized in that: The spray lubrication system (1) includes a nitrogen-containing high-pressure tank (11) for storing nitrogen nitride and a nozzle (12) connected to the nitrogen-containing high-pressure tank (11) via an electrically controlled valve. The electrically controlled valve is controlled by an electrically controlled system (13). The hot upsetting mold (3) is made of silicon nitride ultrahard ceramic.

9. The high-speed extrusion molding process for GH6159 spline bolts adapted to a water-cooled constant-temperature mold frame as described in claim 2, characterized in that: When the head (51) of the billet rod (5) is heated, the rod part (52) of the billet rod (5) is inside the support sleeve (53). The support sleeve (53) is provided with a water flow cooling space (54). Cooling water is introduced into the water flow cooling space (54) to cool the rod part (52).

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