Forging equipment and forging method for large bucket teeth

Abstract

The forging equipment comprises a bucket tooth mold, a charging barrel and a mold cavity, the mold cavity is formed in the bucket tooth mold, a bucket cavity core is arranged in the mold cavity, the bucket cavity core is a water-cooling metal core, a cooling water channel is formed in the bucket cavity core, and the bucket cavity core and the bucket tooth mold are connected in a drawable mode; in the bucket tooth manufacturing process, the bucket cavity core is used for assisting in forming the bucket cavity shape of the bucket tooth and can be pulled out of the die cavity after the bucket tooth is formed, and the charging barrel is perpendicular to the die cavity and used for containing a liquid bucket tooth material so that the material can be loaded into the die cavity under the action of gravity and rheological pressure. Wherein the bucket tooth mold is externally connected with a plurality of pressurizing oil cylinders, so that a plurality of vertical and horizontal pressures are provided for the bucket tooth mold.

Description

Technical Field

[0001] The present application relates to the technical field of bucket tooth forging, and in particular to a forging device and a forging method for large bucket teeth. Background Art

[0002] Currently in the field of engineering machinery, bucket teeth, as key wear-resistant and consumable parts of excavators, bulldozers and other equipment, are mainly composed of tooth roots and tooth tips. Their performance directly affects the operating efficiency and service life of the equipment.

[0003] At present, small bucket teeth can be manufactured by forging or casting, but large bucket teeth with a unit weight of more than 100kg can usually only be produced by casting. Although cast bucket teeth are more flexible in material selection, covering a variety of processes such as sand casting, precision casting, and lost foam casting, they all have obvious disadvantages. During the casting process, the liquid bucket tooth material that has been smelted in a smelting furnace and meets the standards is injected into a disposable sand mold by gravity for cooling and solidification. The shape of the bucket tooth, the pin hole, and the tooth cavity are shaped by the sand mold and the sand core respectively, but this also leads to its process yield rate of less than 70%. Since a large riser that accounts for about 50-80% of the weight of the bucket tooth must be set to prevent casting defects, the material and energy consumption is greatly increased. At the same time, sand casting will produce serious dust pollution in the preparation and grinding and cleaning of sand molds and sand cores, which is easy to cause silicosis; the wax pressing and shell making processes of precision casting will emit a large amount of wastewater and pungent odors; lost foam casting will have plastic mold gasification waste gas discharged during pouring, and the overall working environment is poor. Moreover, the microstructure of cast bucket teeth is coarse, the impact toughness is poor, the performance is unstable, and the broken tooth rate during use is as high as 10% - 20%. In addition, the tooth cavity and pin hole formed by sand core have low precision, and they are often scrapped due to poor fit with the tooth seat or pin.

[0004] Forged bucket teeth are an emerging manufacturing technology. They are made by heating the continuous casting or rolling steel billet to 100-200℃ below the solidus, placing it in a metal mold cavity, and using a forging machine for plastic deformation. They have a fine structure, and the V-notch impact energy at room temperature of the same material is 5-10J higher than that of cast bucket teeth, and the tooth breakage rate is generally below 5%. However, due to the shortage of large-tonnage forging machines and large-size billets, it is difficult to forge large bucket teeth with existing technology.

[0005] Previously, someone studied the liquid die forging process of D11 bucket teeth and proposed direct liquid forging under pressure in a single-cavity upright position. Although the direct liquid forging adopts a concave-convex die structure, it is prone to cold shut defects and the tooth cavity accuracy is difficult to guarantee. In summary, the existing technology for manufacturing large bucket teeth faces the difficulties of high tooth breakage rate and short service life. It is urgent to solve the impact performance and tooth breakage rate problems of cast large bucket teeth, and to break through the limitations of forging methods in materials and production of large bucket teeth. Summary of the invention

[0006] The purpose of the present application is to provide a forging device and a forging method for large bucket teeth, so as to solve the problems of high tooth breakage rate and short service life faced by the existing technology for manufacturing large bucket teeth.

[0007] To achieve the above purpose, the technical solution adopted in the present application is: a forging equipment for large bucket teeth, comprising: a bucket tooth mold, a barrel and a mold cavity, the mold cavity is arranged in the bucket tooth mold, a bucket cavity core is arranged in the mold cavity, the bucket cavity core is a water-cooled metal core, a cooling water channel is arranged inside the bucket cavity core, and the connection method between the bucket cavity core and the bucket tooth mold is a removable connection. During the bucket tooth manufacturing process, the bucket cavity core is used to assist in forming the bucket cavity shape of the bucket tooth, and the bucket cavity core can be pulled out from the mold cavity after the bucket tooth is formed. The barrel is arranged perpendicular to the mold cavity, and the barrel is used to hold liquid bucket tooth material so that the material can be loaded into the mold cavity under the action of gravity and rheological pressure; wherein, a plurality of pressurized cylinders are connected to the bucket tooth mold to provide multiple vertical and horizontal pressures to the bucket tooth mold.

[0008] As a preferred embodiment, the pressurizing cylinder includes a main cylinder providing vertical downward pressurization, an extrusion cylinder for vertical downward pressurization, a lower top cylinder for vertical upward pressurization, a mold clamping cylinder for vertical downward pressurization, a horizontally pressurized mold locking cylinder, a horizontally pressurized bucket cavity or notch core pulling cylinder, and a horizontally pressurized pin hole core pulling cylinder.

[0009] As another preferred embodiment, the bucket tooth mold is also connected to a push rod, an upper pressure head and a lower pressure head. The push rod is located above the mold cavity, and is used to assist the flow of liquid bucket tooth material during the forging process and to eject the bucket tooth after forming; and the barrel is arranged close to the push rod, and the upper pressure head is located above the barrel. The upper pressure head is connected to the pressurized cylinder, and the liquid bucket tooth material in the barrel can be pressed into the mold cavity through pressure. The lower pressure head is located at the bottom of the mold cavity relative to the upper pressure head, and cooperates with the push rod to fill the mold cavity with liquid bucket tooth material.

[0010] Further preferably, a forging method for large bucket teeth is provided, and the forging method is applicable to a forging device for large bucket teeth as described in any one of the above, and the forging method comprises: step S10: using a variety of metals as raw materials to melt and cast liquid bucket tooth material; step S20: loading the liquid bucket tooth material into a mold cavity with a removable bucket tooth core, or into a barrel under gravity and rheological pressure; step S30: pressurizing the liquid bucket tooth material in the mold cavity or barrel to a first set pressure determined according to the bucket tooth size within a first set time after loading, so that the liquid bucket tooth material rheologically fits the mold cavity wall and cools and solidifies; step S40: increasing the pressure to a second set pressure determined according to the bucket tooth size and maintaining the pressure for a second set time, so that the bucket tooth material rheologically solidifies and the bucket cavity core is pulled out after shrinkage compensation, and the bucket tooth is opened to take out the bucket tooth; step S50: performing preliminary heat treatment and tempering heat treatment on the bucket tooth after demolding to obtain a large forged bucket tooth.

[0011] Preferably, step S20 further includes: the weight of the liquid bucket tooth material is between 1.05 and 1.2 times the weight of the bucket tooth, the shape of the mold cavity is consistent with the shape of the bucket tooth, and the size of the mold cavity has a shrinkage allowance of 1.3 to 1.5%.

[0012] Preferably, step S30 also includes: monitoring the loading speed of the material during the loading process; when the loading speed deviates from the preset speed by more than a first set value; immediately stopping the loading and checking the loading system.

[0013] Further preferably, step S30 also includes: monitoring the temperature change of the liquid bucket tooth material during the pressurization process and the fit with the mold cavity wall; if the material temperature drops by more than the second set value within a certain period of time, detecting whether the mold preheating system is normal; if it is judged as no, reducing the pressurization speed and issuing an alarm; if it is judged as yes, appropriately increasing the mold preheating temperature according to the material characteristics, and judging whether the displacement deviation of the liquid bucket tooth material and the mold cavity wall exceeds the third set value; if it is judged as yes, gradually increasing the pressure, each time increasing the fourth set value, until the displacement deviation is within the allowable range; if it is judged as no, operating normally.

[0014] Further preferably, monitoring the temperature change of the liquid bucket tooth material during the pressurization process also includes: real-time detection to determine whether an abnormal temperature increase or decrease occurs in a local area of ​​the mold; if it is determined to be no, normal pressurization is performed; if it is determined to be yes, the working parameters of the pressurization cylinder are adjusted to make the pressure evenly distributed, and at the same time, checking to determine whether the cooling water pipeline is blocked or the cooling water flow rate is abnormal; if it is blocked, the pipeline is cleaned, and if the flow rate is abnormal, it is adjusted to an appropriate range to ensure uniform and stable cooling effect of the mold.

[0015] Further preferably, in the process of gradually increasing the pressure, after each increase of the fourth set value, it is necessary to wait for the fifth set time interval and re-check whether the displacement deviation between the liquid bucket tooth material and the mold cavity wall is within the allowable range; if it is still beyond the allowable range, continue to increase the pressure until the displacement deviation is within the allowable range or the cumulative number of pressure increases reaches the sixth set number; if the displacement deviation still does not meet the requirement after the cumulative number of pressure increases reaches the sixth set number, it is determined that the forging process is abnormal, an alarm is issued and the operation is stopped, and relevant data is recorded for subsequent analysis and improvement.

[0016] Further preferably, when it is necessary to gradually increase the pressure, the fluidity of the liquid bucket tooth material is detected before each pressure increase; if the fluidity is within the seventh setting range, the pressure is increased; if the fluidity is lower than the lower limit of the seventh setting range, the pressure increase operation is suspended, and the material is heated or a suitable amount of flux is added to restore its fluidity to an acceptable range before continuing the pressure increase operation.

[0017] Compared with the prior art, the beneficial effects of this application are: By melting steel materials by ourselves, we are no longer limited by the standard materials of steel mills. We can flexibly adjust the composition, temperature and heat treatment process of bucket tooth materials according to actual working conditions and service conditions, give full play to the material potential and meet the performance requirements of large bucket teeth. Multiple pressurized oil cylinders are used to provide multi-directional pressure on bucket tooth molds. During the pressurized solidification process, high pressure uses almost all the process surplus materials to compensate for shrinkage. There are no cast risers and traditional forging flash, making the process yield rate as high as 92-98%, greatly improving material utilization and reducing costs.

[0018] The high pressure during the forging process and automated production make the internal structure of the bucket teeth fine, strong, coordinated, highly consistent in performance, and with a low tooth breakage rate, thus improving the performance of the bucket teeth. Even when working under low temperature and high impact conditions of -40°C, the tooth breakage rate is no more than 2%. Compared with the existing casting and forging large bucket tooth technologies, the reliability and service life of the bucket teeth have been significantly improved.

[0019] Regarding the forming accuracy of bucket teeth, a removable water-cooled metal bucket cavity core and other structures are set in the bucket tooth mold, which helps to ensure the dimensional accuracy of the bucket teeth, avoids problems such as low precision of tooth cavity and pin hole caused by sand core molding, and reduces the situation of scrapping due to poor fit.

[0020] It breaks through the limitation of existing forging technology that cannot produce large bucket teeth due to the shortage of large-tonnage forging machines and large-size billets, and is suitable for the manufacture of various large bucket teeth to meet the market demand for large bucket teeth. At the same time, detailed monitoring and control methods are set for the loading, pressurization, solidification and other links of liquid bucket tooth materials during the forging process, further ensuring the forging quality of large bucket teeth. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the structure of the forging equipment for large bucket teeth from the main perspective.

[0022] Figure 2 This is a schematic diagram of the structure of the forging equipment for large bucket teeth from a top view.

[0023] In the figure: 1. Forging equipment for large bucket teeth; 10. Bucket tooth mold; 20. Cylinder; 30. Cavity; 40. Cavity core; 50. Pressurizing cylinder; 51. Main cylinder; 52. Extrusion cylinder; 53. Lower ejector cylinder; 54. Clamping cylinder; 55. Locking cylinder; 56. Notch core-pulling cylinder; 57. Pin hole core-pulling cylinder; 60. Ejector rod; 70. Upper pressure head; 80. Lower pressure head; 81. Pressure head sleeve. DETAILED DESCRIPTION

[0024] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0025] In the description of the present application, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of narrating the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific scope of protection of the present application.

[0026] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0027] The terms "including" and "having" and any variations thereof in the specification and claims of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0028] In a preferred embodiment, see Figure 1 to Figure 2The present application provides a forging device 1 for a large bucket tooth, comprising: a bucket tooth mold 10, a barrel 20 and a mold cavity 30, wherein the mold cavity 30 is arranged in the bucket tooth mold 10, and a bucket cavity core 40 is arranged in the mold cavity 30, the bucket cavity core 40 is a water-cooled metal core, and a cooling water channel is arranged inside the bucket cavity core 40, and the bucket cavity core 40 is connected to the bucket tooth mold 10 in a removable manner. During the bucket tooth manufacturing process, the bucket cavity core 40 is used to assist in forming the bucket cavity shape of the bucket tooth, and the bucket cavity core 40 can be pulled out from the mold cavity 30 after the bucket tooth is formed. The barrel 20 is arranged perpendicular to the mold cavity 30, and the barrel 20 is used to contain liquid bucket tooth material so that the material can be loaded into the mold cavity 30 under the action of gravity and rheological pressure; wherein, a plurality of pressurized oil cylinders 50 are externally connected to the bucket tooth mold 10 to provide a plurality of vertical and horizontal pressures to the bucket tooth mold 10.

[0029] As a preferred embodiment, the pressurizing cylinder 50 includes a main cylinder 51 for providing vertical downward pressurization, an extrusion cylinder 52 for vertical downward pressurization, a lower push cylinder 53 for vertical upward pressurization, a mold closing cylinder 54 for vertical downward pressurization, a locking cylinder 55 for horizontal pressurization, a bucket cavity or notch core pulling cylinder 56 for horizontal pressurization, and a pin hole core pulling cylinder 57 for horizontal pressurization, wherein the main cylinder 51 provides pressure P1, the extrusion cylinder 52 provides pressure P2, the locking cylinder 55 provides pressure P3, the lower push cylinder 53 provides pressure P4, the bucket cavity or notch core pulling cylinder 56 provides pressure P5, the pin hole core pulling cylinder 57 provides pressure P6, and the mold closing cylinder 54 provides pressure P7, and the various cylinder bodies cooperate to complete functions such as mold closing, mold locking, pushing, extrusion, and core pulling.

[0030] As another preferred embodiment, the bucket tooth mold 10 is also connected with a push rod 60, an upper pressure head 70 and a lower pressure head 80. The push rod 60 is located above the mold cavity 30, and is used to assist the flow of liquid bucket tooth material and eject the bucket tooth after forming during the forging process; and the barrel 20 is arranged close to the push rod 60, and the upper pressure head 70 is located above the barrel 20. The upper pressure head 70 is connected to the pressurized cylinder 50, and the liquid bucket tooth material in the barrel 20 can be pressed into the mold cavity 30 through pressure. The lower pressure head 80 is located at the bottom of the mold cavity 30 relative to the upper pressure head 70, and the lower pressure head 80 is also covered with a pressure head cover 81 to reduce the operating loss of the lower pressure head 80. The lower pressure head 80 cooperates with the push rod 60 to fill the mold cavity 30 with liquid bucket tooth material.

[0031] Preferably, the forging equipment in the present application document does not use solid billets, but rather liquid bucket tooth materials melted online, whose temperature is higher than the liquidus temperature, and whose chemical composition is flexibly designed and configured, and then the bucket teeth are liquid die forged using the forging equipment in the present application document.

[0032] Further preferably, a forging method for a large bucket tooth is provided, the forging method is applicable to the forging device 1 for a large bucket tooth as described in any one of the above, the forging method comprising: step S10: using a variety of metals as raw materials to melt and cast liquid bucket tooth materials, and in this stage of melting and casting bucket tooth materials, using scrap steel, ferrochrome, ferromanganese, ferromolybdenum, ferrotitanium, ferrosilicon, aluminum rare earth and other alloy materials and recycled materials as raw materials, according to the content requirements of the alloy elements, and using a smelting furnace to melt the chemical composition and temperature The liquid tooth material having a temperature higher than the liquidus temperature; Step S20: rheological loading process, the liquid tooth material is loaded into the mold cavity 30 with a removable tooth core under gravity and rheological pressure, or loaded into the barrel 20, the mold cavity 30 includes a single mold cavity 30 and a multi-mold cavity 30, the mold cavity 30 is made of hot working die steel, and at the same time, a removable water-cooled metal core is placed at the pin hole, bucket cavity and notch of the tooth, the water-cooled metal core is made of hot working die steel, and the inner The temperature of the bucket tooth is regulated by cooling water, and the water-cooled metal core is also the bucket cavity core 40; the barrel 20 is a cylinder made of mold steel or high-aluminum refractory material; step S30: pressurizing and filling the mold cavity 30, and pressurizing the liquid bucket tooth material in the mold cavity 30 or the barrel 20 to a first set pressure determined according to the bucket tooth size within the first set time after loading, so that it rheologically fits the inner wall of the mold cavity 30 and cools and solidifies. Preferably, the first set pressure is determined according to the bucket tooth size to ensure that the pressure acting on the liquid bucket tooth material is 20-60MPa, and the first set time is within the range of 5 to 20 seconds according to the bucket tooth weight; step S40: pressurization and solidification stage, increase the pressure to a second set pressure determined according to the bucket tooth size and maintain the second set time, so that the bucket tooth material rheologically solidifies and compensates for shrinkage, then the bucket cavity core 40 is pulled out, the mold is opened and the bucket tooth is taken out. Specifically, when the second set time is reached, the pin hole core, the bucket cavity core 40 and the notch core are pulled out, the bucket tooth mold 10 is opened, and the bucket tooth is taken out. The second set pressure is determined according to the bucket tooth size, which means that the pressure acting on the liquid bucket tooth material is 120-200MPa, and the second set time is equal to 1.10-1.30 times the total solidification time of the bucket tooth; Step S50: Perform preliminary heat treatment and tempering heat treatment on the bucket tooth after demolding to obtain a large forged bucket tooth.

[0033] Preferably, in step S20, the weight of the liquid bucket tooth material is between 1.05 and 1.2 times the weight of the bucket tooth, and the shape of the mold cavity 30 is consistent with the shape of the bucket tooth, and the size of the mold cavity 30 allows for a shrinkage of 1.3 to 1.5%.

[0034] Furthermore, in the forging method of large bucket teeth in the present application document, the entire manufacturing process is controlled by a fully automatic PLC, and the PLC program flow is as follows: the main cylinder 51 is quickly lowered, and then the main cylinder 51 is slowly lowered to the mold closing position, and then the mold closing cylinder 54 is pushed to the set pressure, and then the mold closing cylinder 54 returns, and the mold locking cylinder 55 is connected to advance, and the mold locking cylinder 55 is connected to increase the pressure to the set pressure, and then the lower top cylinder 53 is pushed to the pouring position, and the pouring machine is connected to advance, so as to quantitatively pour the set amount, and then the lower top cylinder 53 returns, and continues to pour to a certain amount until the pouring machine exits, and then The main cylinder 51 moves down quickly to the switching position, and then the main cylinder 51 moves down slowly to increase the pressure to the set pressure. Then the extrusion cylinder 52 moves down quickly, and then the extrusion cylinder 52 moves down slowly to increase the pressure, until the extrusion cylinder 52 increases the pressure to the first set pressure and holds the pressure. After that, the extrusion cylinder 52 continues to increase the pressure to the second set pressure and holds the pressure, entering the pressure holding delay stage. After the delay, the extrusion cylinder 52 returns, and then the locking cylinder 55 returns to relieve the pressure, and then the main cylinder 51 is connected to relieve the pressure, and then the main cylinder 51 returns to the mold opening position, the pick-up machine is put into place, and the main cylinder 51 continues to return to the punching position, and then the pick-up machine returns, thus entering the next cycle.

[0035] Preferably, step S30 also includes: monitoring the loading speed of the material during the loading process; when the loading speed deviates from the preset speed by more than a first set value; immediately stopping the loading and checking the loading system.

[0036] Further preferably, step S30 also includes: monitoring the temperature change of the liquid bucket tooth material during the pressurization process and the fit with the inner wall of the mold cavity 30; if the material temperature drops by more than the second set value within a certain period of time, detecting whether the mold preheating system is normal; if it is judged as no, reducing the pressurization speed and issuing an alarm; if it is judged as yes, appropriately increasing the mold preheating temperature according to the material characteristics, and at the same time judging whether the displacement deviation of the liquid bucket tooth material and the inner wall of the mold cavity 30 exceeds the third set value; if it is judged as yes, gradually increasing the pressure, each time increasing the fourth set value, until the displacement deviation is within the allowable range; if it is judged as no, operating normally.

[0037] Further preferably, monitoring the temperature change of the liquid bucket tooth material during the pressurization process also includes: real-time detection to determine whether an abnormal temperature increase or decrease occurs in a local area of ​​the mold; if it is determined to be no, normal pressurization is performed; if it is determined to be yes, the working parameters of the pressurization cylinder 50 are adjusted to make the pressure evenly distributed, and at the same time, checking to determine whether the cooling water pipeline is blocked or the cooling water flow rate is abnormal; if it is blocked, the pipeline is cleaned, and if the flow rate is abnormal, it is adjusted to an appropriate range to ensure uniform and stable cooling effect of the mold.

[0038] Further preferably, in the process of gradually increasing the pressure, after each increase of the fourth set value, it is necessary to wait for the fifth set time interval and check again whether the displacement deviation between the liquid bucket tooth material and the inner wall of the mold cavity 30 is within the allowable range; if it is still beyond the allowable range, continue to increase the pressure until the displacement deviation is within the allowable range or the cumulative number of pressure increases reaches the sixth set number; if the displacement deviation still does not meet the requirement after the cumulative number of pressure increases reaches the sixth set number, it is determined that there is an abnormality in the forging process, an alarm is issued and the operation is stopped, and relevant data is recorded for subsequent analysis and improvement.

[0039] Further preferably, when it is necessary to gradually increase the pressure, the fluidity of the liquid bucket tooth material is detected before each pressure increase; if the fluidity is within the seventh setting range, the pressure is increased; if the fluidity is lower than the lower limit of the seventh setting range, the pressure increase operation is suspended, and the material is heated or a suitable amount of flux is added to restore its fluidity to an acceptable range before continuing the pressure increase operation.

[0040] Among them, in a preferred embodiment, the material weight ratio parameter is as follows: the weight of the liquid bucket tooth material is 1.1 times the weight of the bucket tooth. The shrinkage parameter is as follows: the size of the mold cavity 30 leaves a 1.4% shrinkage. Loading speed parameter: The preset loading speed is 8L / min, and the first setting value (allowable speed deviation) is 15%. That is, when the loading speed is lower than 6.8L / min or higher than 9.2L / min, the abnormal processing is triggered. Temperature parameter: The second setting value (the temperature drop rate allowed for the material during the pressurization process) is 6℃ / min, the third setting value (the allowable displacement deviation with the inner wall of the mold cavity 30) is 0.3mm, and the seventh setting range (the acceptable range of the fluidity of the liquid bucket tooth material) is preferably 5-8. Pressure parameter: The fourth setting value (the pressure value increased each time) is 8MPa, the fifth setting time interval (the waiting time for detection after each pressure increase) is 5s, and the sixth setting number (the maximum number of cumulative pressure increases) is 5 times.

[0041] Furthermore, during the loading process, the material loading speed is monitored by the flow sensor module. When the control system detects that the loading speed deviates from the preset speed of 8L / min by more than 15%, the loading is stopped immediately. Subsequently, check whether the barrel 20 or the mold cavity entrance is blocked by impurities. If there is a blockage, use special tools to clean it; at the same time, check whether the pressure system pipeline is leaking or the pressure regulating valve is faulty. If there is a problem, repair or replace the parts in time, and restart loading after the problem is solved.

[0042] The temperature detection module monitors the temperature change of the liquid bucket tooth material in real time during the pressurization process. If the temperature detection module detects that the material temperature drops by more than 6°C within 1 minute, it will detect whether the mold preheating system is working properly. If the mold preheating system is abnormal, the control system will automatically reduce the pressurization speed and issue an alarm to prompt the operator to check the preheating system; if the mold preheating system is normal, the mold preheating temperature will be appropriately increased according to the material characteristics, but the maximum temperature will not exceed the upper limit allowed by the material.

[0043] At the same time, the temperature detection module also detects in real time whether the temperature in the local area of ​​the mold is abnormally increased or decreased. If no abnormality is found, normal pressure is applied; if the local temperature is found to be abnormally increased or decreased, the working parameters of the pressurized oil cylinder 50 are adjusted to make the pressure evenly distributed, and at the same time, it is checked to determine whether the cooling water pipeline is blocked or the cooling water flow rate is abnormal. If the cooling water pipeline is blocked, it is cleaned; if the flow rate is abnormal, it is adjusted to an appropriate range (such as 2.5L / min) to ensure uniform and stable cooling of the mold.

[0044] The displacement sensor is used to monitor the fit of the liquid tooth material and the inner wall of the die cavity 30. When it is determined that the displacement deviation of the liquid tooth material and the inner wall of the die cavity 30 exceeds 0.3mm, the pressure is gradually increased by 8MPa each time, and after each pressure increase, wait for 5s to check again whether the displacement deviation is within the allowable range. If it is still beyond the allowable range, the pressure is continued to be increased until the displacement deviation is within the allowable range or the cumulative pressure increase times reaches 5 times. If the displacement deviation still does not meet the requirements after the cumulative pressure increase times reaches 5 times, it is determined that the forging process is abnormal, an alarm is issued, and the operation is stopped, and the relevant data is recorded for subsequent analysis and improvement.

[0045] Before increasing the pressure each time, use a special fluidity testing device to test the fluidity of the liquid bucket tooth material. If the fluidity is between 5 and 8, increase the pressure; if the fluidity is lower than 5, stop increasing the pressure, heat the material (such as by adjusting the mold preheating temperature or using an external heating device) or add an appropriate amount of flux, etc., to restore its fluidity to an acceptable range before continuing to increase the pressure.

[0046] Among them, in this application, large bucket teeth of different specifications and materials are successfully manufactured through unique forging equipment and processes. Taking the KT390gy tooth seat as an example, its single weight reaches 117kg. According to the process of this application, the loading amount is 245Kg, and 20CrMnSi material is selected for double-cavity die forging. In the manufacturing process, firstly, a smelting furnace is used to melt the liquid bucket tooth material that meets the component requirements, and then the liquid bucket tooth material is loaded into a double-cavity mold cavity 30 with a removable bucket tooth core under the action of gravity and rheological pressure. The shape of the mold cavity 30 is consistent with the shape of the tooth seat and the size reserves 1.3-1.5% of the shrinkage. After loading, the liquid bucket tooth material in the mold cavity 30 is pressurized to the first set pressure determined according to the tooth seat size within a specific time, so that it rheologically fits the inner wall of the mold cavity 30 and cools and solidifies. During this process, the material loading speed, temperature changes during pressurization, and the fit with the inner wall of the mold cavity 30 are strictly monitored to ensure the stability of the forging process. Then the pressure is increased to the second set pressure and maintained for a corresponding time, so that the bucket tooth material rheologically solidifies and compensates for shrinkage, the bucket cavity core 40 is pulled out, the mold is opened, and the tooth seat is taken out. Finally, the tooth seat after demolding is subjected to residual heat quenching and tempering heat treatment. The resulting tooth seat can reach an impact toughness of 60J at -40℃, a hardness of 40-46HRC, and a tooth breakage rate of only 1.2%.

[0047] Similarly, the FM950RC tooth tip is similar, with a unit weight of 104kg, a loading volume of 215Kg, and a material of 30CrMnSiMoNi. It also undergoes double-cavity die forging and corresponding heat treatment processes. The impact toughness can reach 25-30J at -40℃, the hardness is 50-53HRC, and the tooth breakage rate is 1.1%.

[0048] For bucket teeth with a unit weight of 260kg and 300kg, the loading amount is 550Kg and 650Kg respectively, and the materials are all CrMnSiMoNi. They are also subjected to double-cavity die forging and appropriate heat treatment processes, and show good impact toughness and hardness at -40°C, and the tooth breaking rate is as low as 0.9% and 0.5% respectively. These embodiments fully prove that the large bucket tooth forging method of the present application can effectively improve the performance of bucket teeth and reduce the tooth breaking rate when producing large bucket teeth, and is suitable for the manufacture of large bucket teeth of different weights and materials, and has strong practicality and reliability.

[0049] Among them, there is no restriction on the material of the bucket teeth in this application document, and the composition, temperature and heat treatment process method can be flexibly adjusted according to the working conditions and service conditions, so that the material potential can be fully utilized. And the bucket teeth in this application document have fine internal structure, strong and coordinated, high performance consistency and low tooth breakage rate due to high pressure and automated production; even if working under low temperature and high impact conditions of -40℃, the tooth breakage rate is no more than 2%. The specifications of the bucket teeth are not limited, and they are suitable for various large bucket teeth in the existing technology; at the same time, the process yield is high, because the high pressure uses almost all the process surplus materials to compensate for shrinkage, there is no casting riser, and there is no flash of the existing forging technology, and the process yield is as high as 92~98%.

[0050] The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and the specification only describe the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the attached claims and their equivalents.

Claims

1. A forging device for large bucket teeth, characterized in that: include: A bucket tooth mold, a barrel and a mold cavity, wherein the mold cavity is arranged in the bucket tooth mold, a bucket cavity core is arranged in the mold cavity, the bucket cavity core is a water-cooled metal core, a cooling water channel is arranged inside the bucket cavity core, and the bucket cavity core is connected to the bucket tooth mold in a removable manner. During the bucket tooth manufacturing process, the bucket cavity core is used to assist in forming the bucket cavity shape of the bucket tooth, and the bucket cavity core can be pulled out from the mold cavity after the bucket tooth is formed. The barrel is arranged perpendicular to the mold cavity, and the barrel is used to contain liquid bucket tooth material so that the material can be loaded into the mold cavity under the action of gravity and rheological pressure; Wherein, the bucket tooth mold is externally connected to a plurality of pressurized oil cylinders to provide a plurality of vertical and horizontal pressures to the bucket tooth mold.

2. The forging equipment for large bucket teeth according to claim 1, characterized in that: The pressurizing cylinders include a main cylinder providing vertical downward pressurization, an extrusion cylinder for vertical downward pressurization, a lower top cylinder for vertical upward pressurization, a mold clamping cylinder for vertical downward pressurization, a horizontally pressurized mold locking cylinder, a horizontally pressurized bucket cavity or notch core pulling cylinder, and a horizontally pressurized pin hole core pulling cylinder.

3. The forging equipment for large bucket teeth according to claim 2, characterized in that: The bucket tooth mold is also connected to a push rod, an upper pressure head and a lower pressure head. The push rod is located above the mold cavity and is used to assist the flow of liquid bucket tooth material during the forging process and to eject the bucket tooth after forming; and the barrel is arranged close to the push rod, the upper pressure head is located above the barrel, and the upper pressure head is connected to the pressurized oil cylinder. The liquid bucket tooth material in the barrel can be pressed into the mold cavity through pressure. The lower pressure head is located at the bottom of the mold cavity relative to the upper pressure head, and cooperates with the push rod to fill the mold cavity with liquid bucket tooth material.

4. A forging method for large bucket teeth, characterized in that: The forging method is applicable to the forging equipment of the large bucket teeth as claimed in any one of claims 1 to 3, and the forging method comprises: Step S10: using a variety of metals as raw materials to melt and cast liquid bucket tooth materials; Step S20: loading the liquid bucket tooth material into a mold cavity with a removable bucket tooth core or into a barrel under gravity and rheological pressure; Step S30: within a first set time after loading, pressurizing the liquid bucket tooth material in the mold cavity or barrel to a first set pressure determined according to the bucket tooth size, so that the liquid bucket tooth material can flow and fit the mold cavity wall and cool and solidify; Step S40: increasing the pressure to a second set pressure determined according to the bucket tooth size and maintaining the second set time, so that the bucket tooth material is rheologically solidified and compensated for shrinkage, and then the bucket cavity core is pulled out, the mold is opened, and the bucket tooth is taken out; Step S50: performing preliminary heat treatment and quenching and tempering heat treatment on the bucket teeth after demoulding to obtain large forged bucket teeth.

5. The forging method of large bucket teeth according to claim 4, characterized in that: In step S20, it also includes: the weight of the liquid bucket tooth material is between 1.05 and 1.2 times the weight of the bucket tooth, and the shape of the mold cavity is consistent with the shape of the bucket tooth, and the size of the mold cavity has a shrinkage amount of 1.3% to 1.5%.

6. The forging method of large bucket teeth according to claim 4, characterized in that: The step S30 also includes: monitoring the loading speed of the material during the loading process; When the loading speed deviates from the preset speed by more than a first set value; Stop charging immediately and check the charging system.

7. The forging method of large bucket teeth according to claim 4, characterized in that: Step S30 also includes: Monitor the temperature change of liquid tooth material during pressurization and its fit with the mold cavity wall; If the material temperature drops by more than the second set value within the set time, the mold preheating system is checked to see if it is normal; If the judgment is no, the pressurization speed is reduced and an alarm is issued; If the answer is yes, the mold preheating temperature is appropriately increased according to the material properties, and at the same time, it is determined whether the displacement deviation between the liquid bucket tooth material and the mold cavity wall exceeds a third set value; If the judgment is yes, the pressure is gradually increased, each time by the fourth set value, until the displacement deviation is within the allowable range; If the judgment is no, it runs normally.

8. The forging method of large bucket teeth according to claim 7, characterized in that: Monitoring the temperature change of the liquid bucket tooth material during the pressurization process also includes: real-time detection and judgment of whether the temperature in a local area of ​​the mold is abnormally increased or decreased; If the judgment is no, then pressurize normally; If the answer is yes, adjust the working parameters of the pressurized oil cylinder to make the pressure evenly distributed, and check whether the cooling water pipeline is blocked or the cooling water flow rate is abnormal; If there is blockage, clean the pipeline. If the flow rate is abnormal, adjust it to the set range to ensure uniform and stable mold cooling effect.

9. The forging method of large bucket teeth according to claim 7, characterized in that: In the process of gradually increasing the pressure, after each increase of the fourth set value, it is necessary to wait for the fifth set time interval to detect again whether the displacement deviation between the liquid bucket tooth material and the mold cavity wall is within the allowable range; If it still exceeds the allowable range, continue to increase the pressure until the displacement deviation is within the allowable range or the cumulative number of pressure increases reaches the sixth set number; If the displacement deviation still does not meet the requirement after the cumulative pressure increase times reaches the sixth set times, it is determined that the forging process is abnormal, an alarm is issued and the operation is stopped, and relevant data is recorded for subsequent analysis and improvement.

10. The forging method of large bucket teeth according to claim 9, characterized in that: When it is necessary to increase the pressure gradually, check the fluidity of the liquid tooth material before each increase in pressure; If the fluidity is within the seventh setting range, increase the pressure; If the fluidity is lower than the lower limit of the seventh setting range, the pressure increase operation is suspended, and the material is heated or a proper amount of flux is added to restore the fluidity to an acceptable range before the pressure increase operation is continued.

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