Soaking-type stamping method and apparatus for hot-formed steel

Abstract

The present invention relates to the technical field of hot stamping steel. Disclosed is a soaking-type stamping method and apparatus for hot-formed steel, comprising the following steps: step 1: transporting a prepared blank into a furnace chamber for austenitizing heating, the blank being made of a hot-formed steel material; and step 2: immersing a lower forming punch into a liquid medium within a tank assembly, and placing the heated blank onto a material support frame by means of a loading manipulator, the tank assembly being internally provided with the liquid medium. A soaking-type stamping method is used in the present invention, which, compared to the direct hot-forming method in the prior art, optimizes the structure of a mold, reduces the machining of water channels in hot stamping devices of the prior art, and shortens the processing cycle and reduces costs while broadening the applicable range of materials, solving the issue of oxide scale on uncoated plates and the lime problem of galvanized steel plates, and having low investment costs and being easily controlled for automation.

Description

A soaking stamping method and device for hot-formed steel TECHNICAL FIELD

[0001] The present application relates to the technical field of hot stamping steel, in particular to a soaking stamping method and device for hot-formed steel. BACKGROUND

[0002] In the field of automobile manufacturing, galvanized sheets are widely used due to their excellent corrosion resistance and strength. Galvanized sheets can be found in the body panels, chassis, and internal structural components of automobiles. Through hot forming processes, galvanized sheets can be processed into complex shapes to meet various design requirements of automobiles. This not only improves the appearance quality of automobiles but also enhances their rigidity and durability.

[0003] Currently, the commercial production adopts an indirect hot stamping process, which involves pre-cooling the sheet on a cold mold to more than 95%, then austenitizing, and finally achieving complete deformation and quenching on another mold. The entire process is completed on two sets of molds.

[0004] However, the technicians in this field found the following defects during production: 1. The cost of mold manufacturing and supporting equipment for producing hot-formed steel is high; 2. The temperature control of the sheet is not uniform during production, making it difficult to ensure complete pre-cooling; 3. Systematic production and manufacturing are not achieved, the application is narrow, and the efficiency is low.

[0005] In view of this, we propose a soaking stamping method and device for hot-formed steel to solve the above problems. SUMMARY

[0006] The purpose of the present application is to provide a soaking stamping method and device for hot-formed steel to solve the problems in the background.

[0007] The purpose of the present application can be achieved through the following technical solutions:

[0008] A soaking stamping method and device for hot-formed steel, comprising the following steps: Step 1: transporting the prepared sheet to the furnace for austenitizing heating; wherein the sheet material is hot-formed steel material; Step 2: immersing the lower forming male into the liquid medium of the container assembly, and placing the sheet obtained in Step 1 on the material holder by the feeding manipulator; the top of the material holder is below the liquid level; Step 3: the upper mold is pressed and combined with the lower mold, and the sheet is formed under pressure; Step 4: after the pressure holding is completed, the hot-formed part is ejected from the liquid surface of the liquid medium by the ejection module, and the hot-formed part is taken out.

[0009] As a further solution of the present application, the sheet is transported to the furnace by the material taking manipulator, the heated sheet is placed on the material holder by the feeding manipulator, and the hot-formed part is taken out by the discharging manipulator.

[0010] As a further scheme of the present application, oil is added on the surface of the liquid medium, the oil including industrial rust-proof oil and lubricating oil, and the oil content being set to 100-200 ml.

[0011] As a further scheme of the present application, a plurality of groups of heating rods are arranged inside the tank assembly, and the groups of heating rods are arranged equidistantly.

[0012] As a further scheme of the present application, an error-proof system is arranged in the blanking area, and the error-proof system includes a weight sensing system arranged on the blanking manipulator.

[0013] As a further scheme of the present application, the thickness of the sheet metal of the blank is 1-14 mm.

[0014] As a further scheme of the present application, the liquid level of the liquid medium is controlled to be 0-300 mm above the upper forming surface of the die.

[0015] As a further scheme of the present application, the liquid medium includes water and a solution of water and slow cooling liquid, and the ratio of the slow cooling liquid to the water is controlled to be between 1:5 and 1:10.

[0016] As a further scheme of the present application, in step two, the sheet metal after heating is partially soaked in the liquid medium.

[0017] As a further scheme of the present application, in step two, the soaking time of the sheet metal in the tank is 3-5 s.

[0018] As a further scheme of the present application, in step three, the speed of the upper die when being pressed down is fast first and then slow.

[0019] As a further scheme of the present application, in step three, the holding pressure of the sheet metal when being formed is between 4000-20000 KN, and the holding time is determined according to the following formula: T2=t*5+1, wherein T2 is the holding time and t is the thickness of the sheet metal.

[0020] As a further scheme of the present application, the water level during the stamping process is monitored by a water level monitoring system, and automatic water replenishment is performed based on the monitoring result, and the steps are as follows:

[0021] The real-time water level value of the liquid medium is obtained: the water level value data of a plurality of positions inside the tank assembly are obtained by a sensor, the water level value data are summed and averaged to obtain the real-time water level value HA of the liquid medium;

[0022] The water level influence data are obtained: the water level influence data include the volume influence of the sheet metal and the heat influence of the sheet metal.

[0023] Wherein, the volume influence of the material sheet is the height of the water level rising after the material sheet enters the liquid medium, and the heat influence of the material sheet is the height of the water level falling caused by the evaporation rate increasing when the material sheet enters the liquid medium, and the liquid leaves the water surface in the form of steam;

[0024] The water level influence data acquisition process is:

[0025] The size of the material sheet is acquired, including the length value, width value and height value of the material sheet, and the length value, width value and height value acquired are used to calculate the volume value VX of the material sheet through the volume formula;

[0026] The length value and width value of the container assembly are acquired, and the bottom area SX of the container assembly is calculated through the area formula;

[0027] The formula HX=VX / SX is substituted to obtain the height HX of the influence of the volume of the material sheet on the water level of the liquid medium;

[0028] The heat of the material sheet after austenitizing heating is acquired through the heat formula Q=C*M*Δt, wherein Q is the absorbed heat, M is the mass of the object, C is the specific heat capacity of the substance, and ΔT is the temperature change amount;

[0029] The formula Q=M1*L is used, wherein Q is the total energy, M1 is the mass of the liquid medium evaporation, and L is the latent heat of evaporation of the liquid;

[0030] The mass M1 of the liquid medium evaporation can be obtained through the above-mentioned formulas Q=C*M*Δt and Q=M1*L, the density of the liquid medium is calculated and processed, and the evaporation volume VY of the liquid medium can be obtained;

[0031] The formula HY=VY / SX is substituted to obtain the height HY of the influence of the heat of the material sheet on the water level of the liquid medium;

[0032] The formula HH=HA+HX-HY is used to obtain the water level estimation value HH;

[0033] The water level estimation value HH is compared with the water level threshold range [HM-HN], wherein the water level threshold range is 0-300mm above the lower forming public top surface;

[0034] If HH∈[HM-HN], a production normal signal is generated;

[0035] If HH<HM, a water replenishment signal is generated;

[0036] If HH>HN, a water drainage signal is generated;

[0037] Based on the above-mentioned water drainage signal, the electromagnetic valve drives the water pump to pump out the liquid medium from the inside of the container assembly, so that the water level of the liquid medium is kept within the water level threshold range [HM-HN];

[0038] Based on the above water replenishment signal, the electromagnetic valve drives the water pump to supplement the liquid medium to the inside of the tank assembly, while analyzing the influence factor of the water replenishment time, and based on the influence factor, the speed of water replenishment is regulated to control the water replenishment time within the time period from the completion of heating to the transfer of the material sheet to the material support;

[0039] The minimum value of the height of the liquid medium required to be supplemented is Hmin=HM-HH, and the maximum value of the height of the liquid medium required to be supplemented is Hmax=HN-HH;

[0040] The influence factor of the water replenishment time is obtained by processing the material sheet space transfer time ratio and the material sheet water body transfer time ratio;

[0041] The material sheet space transfer time ratio is the ratio of the time T1 required by the loading manipulator to transfer the heated material sheet to the upper side of the tank assembly to the space transfer standard value T2;

[0042] The material sheet water body transfer time ratio is the ratio of the time T3 required by the loading manipulator to place the material sheet on the material support to the water body transfer standard value T4;

[0043] The influence factor of the water replenishment time is K=T1 / T2+T3 / T4, K is recorded as the influence factor of the water replenishment time;

[0044] According to the formula And Where Tx is the standard time of the time period from the completion of heating to the placement of the material sheet into the liquid medium by the loading manipulator, which is the experience value of the worker;

[0045] Based on the above formula, when the influence factor of the water replenishment time changes, the minimum value of the water replenishment speed is Vx, and the maximum value of the water replenishment speed is Vy, by regulating the water replenishment speed, the water replenishment time is close to the standard time Tx.

[0046] As a further scheme of the present application, it comprises a soaking module, a forming module, a die module and an ejection module;

[0047] The soaking module comprises a tank assembly, and a plurality of heating rods are arranged in the inside of the tank assembly;

[0048] The forming module comprises a lower forming male die arranged on the upper side of the tank bottom plate, and a material support is arranged on both sides of the lower forming male die.

[0049] As a further scheme of the present application, the soaking module comprises a tank assembly, and a plurality of heating rods are arranged in the inside of the tank assembly;

[0050] The tank assembly comprises four groups of tank side plates, and the four groups of tank side plates are arranged in a rectangular shape, two groups of tank upper cover plates are arranged on the upper side of the four groups of tank side plates, and a tank bottom plate is arranged on the lower side of the four groups of tank side plates.

[0051] As a further scheme of the present application, the soaking module further comprises a heat insulation plate assembly comprising heat insulation side plates arranged on the outer surfaces of the tank side plates, a heat insulation bottom plate arranged on the lower side of the heat insulation side plates, and the heat insulation bottom plate is arranged on the lower side of the tank bottom plate.

[0052] The outer surface of the heat insulation side plate is fixedly connected with a junction box.

[0053] The junction box is connected with a temperature control electric cabinet box through a connecting line.

[0054] As a further scheme of the present application, the forming module comprises two groups of lower forming male dies arranged on the upper side of the tank bottom plate, material supporting frames are arranged on the two sides of the two groups of lower forming male dies, and a plurality of positioning pins are arranged on the outer side of the end portions of the two groups of lower forming male dies.

[0055] As a further scheme of the present application, the die seat module comprises a lower die seat and a supporting block, and a liquid pipe opening is arranged on one side of the lower die seat, and the liquid pipe opening is in communication with the inside of the tank assembly.

[0056] As a further scheme of the present application, the ejection module comprises a plurality of ejecting pins arranged on the top surface of the lower forming male die, the ejecting pins are controlled to ascend and descend through an oil cylinder ejection assembly, and the oil cylinder ejection assembly comprises a plurality of oil cylinders and a soft spring oil pipe.

[0057] The present application has the following beneficial effects:

[0058] (1) The present application adopts a soaking stamping method, compared with the direct hot forming method in the prior art, the structure of the die is optimized, the water channel processing of the existing hot stamping equipment is reduced, the processing cycle and cost are reduced, the material application range is widened, the LIME problem of the oxide scale of the non-plated layer plate and the galvanized plate is solved, the investment cost is low, and the automation is easy to control;

[0059] (2) The lower forming male die of the die is immersed in the liquid medium in the inside of the tank assembly, so that the lower forming male die of the die does not need to increase the water channel cooling, thereby reducing the water channel processing of the existing hot stamping equipment, reducing the processing cycle and cost;

[0060] (3) The lower forming male die of the die is soaked in the liquid medium of the tank assembly, and then the temperature of the lower forming male die can be indirectly adjusted by adjusting the temperature of the liquid medium, the possibility of warping of the material sheet after stamping and forming is reduced, and the production qualified rate can be increased;

[0061] (4) The present application has small deformation and small warping degree of the material sheet, and high forming resistance, by locally immersing the material sheet in the liquid medium;

[0062] (5) The present application has the speed fast and then slow during the pressing of the upper mold, which can ensure the production rhythm and prevent the cracking of the part during the forming. BRIEF DESCRIPTION OF DRAWINGS

[0063] The present application will be further described below in combination with the drawings.

[0064] Fig. 1 is a schematic view of the overall structure from the shaft side in the present application;

[0065] Fig. 2 is a schematic view of the overall structure from the bottom in the present application;

[0066] Fig. 3 is a schematic view of the overall structure from the top in the present application;

[0067] Fig. 4 is a schematic view of the metallography of the part in one specific example in the present application;

[0068] Fig. 5 is a schematic view of the strength of the part in one specific example in the present application;

[0069] Fig. 6 is a schematic view of the elongation of the part in one specific example in the present application.

[0070] In the drawings:

[0071] 1, soaking module; 11, container assembly; 111, container side plate; 112, container upper cover plate; 113, container bottom plate; 12, heating rod; 13, junction box; 14, heat insulation plate assembly; 141, heat insulation side plate; 142, heat insulation bottom plate; 15, liquid pipe; 16, temperature control electric cabinet box;

[0072] 2, forming module; 21, lower forming male; 22, material supporting frame; 23, positioning needle;

[0073] 3, mold base module; 31, lower mold base; 32, supporting block;

[0074] 4, ejection module; 41, ejector pin; 42, oil cylinder ejection assembly; 421, soft spring oil pipe; 422, oil cylinder assembly. DETAILED DESCRIPTION

[0075] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0076] Embodiment one

[0077] Referring to FIGS. 1-3, the present application is a hot forming steel immersion stamping method, comprising the following steps:

[0078] Step one: austenitizing;

[0079] Step two: immersion precooling;

[0080] Step three: rapid forming;

[0081] Step four: pick error proofing;

[0082] The immersion stamping method is adopted, compared with the direct hot forming method in the prior art, the structure of the die is optimized, the water channel processing of the existing hot stamping equipment is reduced, the processing cycle and cost are reduced, the material application range is widened, the oxidation scale of the non-coated plate is solved, the LIME problem of the galvanized plate is solved, the investment cost is low, and the automation is easy to control.

[0083] Example two

[0084] Referring to FIGS. 1-3, based on the above example one, the present application is a hot forming steel immersion stamping method, further comprising:

[0085] In step one:

[0086] The sheet material is set as a hot forming steel material, the sheet thickness is 1-14 mm, the prepared sheet is transported to the furnace by the material taking manipulator for austenitizing heating;

[0087] The hot forming steel material includes but is not limited to non-coated plate, aluminum-silicon coated plate, and galvanized plate;

[0088] The heating time is determined according to the formula: T1=100*t+150;

[0089] The above formula is an empirical formula summarized through production experience during the forming process;

[0090] In step two:

[0091] After the sheet is austenitized, the material taking manipulator transports the sheet to the material supporting frame 22 according to the debugged program;

[0092] Compared with the immersion precooling forming method in the prior art, the lower forming male die 21 of the die is immersed in the liquid medium inside the container assembly, so that the lower forming male die 21 of the die does not need to be increased with a water channel cooling, thereby reducing the water channel processing of the existing hot stamping equipment, reducing the processing cycle and cost;

[0093] The container assembly 11 contains liquid medium, the liquid level is controlled at 0-300 mm above the top surface of the forming male die, and the top end of the material supporting frame 22 is ensured to be below the liquid level.

[0094] It should be noted that the water level of the liquid medium is controlled below the top end of the material holder 22 to ensure that the lower die is inside the liquid medium during stamping, pre-cooling is performed by temperature control of the lower die, and the material sheet is ensured not to be inside the liquid before forming, so that after forming, the formed part can be quickly taken out, and at the same time, water will not overflow during stamping, and it is safer during processing;

[0095] Further, the liquid medium includes but is not limited to water and a solution of water and slow cooling liquid, the ratio of the slow cooling liquid to water is controlled between 1:5 and 1:10, and oil is added to the upper surface of the liquid medium,

[0096] The oil includes but is not limited to industrial antirust oil and lubricating oil, and the oil content is controlled between 100-200 ml;

[0097] The purpose of the above ratio is to control the evaporation of water, reduce the heating time of the liquid medium, and stabilize the temperature change, so as to ensure the formation of the gas film;

[0098] The temperature of the liquid medium is controlled in the range of 80-100℃, and the heating form includes but is not limited to the heating rod 12 arranged inside the container assembly 11, and the temperature control form includes but is not limited to the temperature measurement rod feedback control;

[0099] Due to the Leidenfrost effect, when the temperature of the material sheet is too high, the liquid near the surface of the material sheet will form film boiling and form a layer of gas film to wrap the material sheet, which can reduce the heat exchange between the material sheet and the liquid and reduce the heat exchange coefficient, so as to ensure that the temperature of the material sheet is far above the martensite transformation temperature before the upper die is pressed to form;

[0100] According to the above process, after austenitizing the material sheet, the lower forming male 21 of the die is soaked in the liquid medium, the lower forming male 21 is temperature controlled, and then the material sheet is stamped, so as to reduce the dimensional deformation of the material sheet during processing and improve the production efficiency and yield;

[0101] In step three:

[0102] The pressing speed needs to be fast first and then slow, and the holding pressure during forming is between 4000-20000KN;

[0103] The holding time is determined according to the material thickness formula: T2=t*5+1;

[0104] When the die is pressed to contact the material sheet, the gas film on the surface of the material sheet will be destroyed, the heat exchange form between the material sheet and the liquid will change from film boiling to excessive boiling, and the heat exchange will gradually increase;

[0105] During the period of the blank forming to the pressure maintaining, the heat exchange finally becomes the nucleate boiling, the heat exchange increases the cooling rate, and the material structure of the formed part finally becomes the martensite.

[0106] In step four:

[0107] After the pressure maintaining, the hot press formed part is ejected from the water surface by the mold ejecting module 4, and then is taken out by the blanking manipulator according to the set program.

[0108] Further, the parts on the mold are prevented from not being taken out in time to cause the mold damage and the beat production, and an error proofing system is arranged in the blanking area.

[0109] The error proofing system includes but is not limited to the following two forms:

[0110] A weight sensing system is additionally arranged on the blanking manipulator, and the weight sensing error proofing is set during the production.

[0111] A visual system is additionally arranged above the blanking manipulator, and the error proofing is detected by the visual counting mode.

[0112] Embodiment three

[0113] Based on the above embodiment two, in step two of the soaking type stamping method of the hot formed steel, the blank is partially soaked in the liquid medium. The thickness of the blank soaked in the liquid is not more than 80% of the thickness of the plate. Since the blank is partially soaked in the liquid, compared with the full soaking scheme, the instantaneous cooling rate of the blank will be reduced, which avoids the warping and deformation of the blank caused by the sharp cooling. At the same time, since the cooling is less, the temperature of the blank during forming is higher, the forming performance of the material is better, and thus the forming resistance during partial soaking is also reduced.

[0114] Embodiment four

[0115] Based on the liquid level control above 0-300mm of the forming top surface, while ensuring that the top pin conical surface is exposed to the liquid surface, the soaking time of the blank in the container is the time from the blanking of the manipulator to the pressing of the upper mold, and the time is usually 3-5s. The pressing speed is fast first and then slow, the pressure maintaining pressure during forming is between 4000-20000KN, and the pressure maintaining time is according to the formula: T2=t*5+1.

[0116] If the soaking time is too short, the surface coating cannot be converted from liquid to solid, which may cause liquid induced crack defects during subsequent forming. If the soaking time is too long, the temperature of the blank (blank) will drop too much, which will cause the transformation of the structure of the blank from austenite to martensite, making the subsequent forming become extremely difficult or impossible. The soaking time is set to 3-5s, which can prevent the liquid induced crack defects during subsequent forming, and also will not cause the temperature of the blank to drop too much.

[0117] When the pressing is performed, the initial speed is 1000-1500 mm / s, and the speed after contacting the blank is 100-150 mm / s. The initial speed is fast to ensure the rapid descent of the press and the production rhythm. The speed is slowed down after contacting the blank to ensure the formability, because too fast forming speed will cause the part to crack.

[0118] The embodiment also has the following specific embodiments, which include:

[0119] During the stamping process, the liquid medium is controlled at the upper side of the lower forming punch 21 and the lower side of the top end of the material supporting frame 22. Placing the material sheet to the upper side of the lower forming punch 21 by the material loading manipulator will collide with the liquid medium and cause the loss of the liquid. After multiple stamping, the liquid will continue to be lost, causing the water level of the liquid medium to change, which will affect the production process.

[0120] Therefore, a water level monitoring system is needed to monitor the water level during the stamping process and automatically supplement water based on the monitoring results.

[0121] The water level monitoring system includes a real-time monitoring module, an analysis and identification module, a water level control module, an automatic water supplement module, and a cloud server.

[0122] Real-time monitoring module: monitor the real-time water level of the liquid medium before the material sheet is added to the liquid medium, and obtain water level influence data, and send these data to the cloud server.

[0123] Analysis and identification module: based on the data received by the cloud server, the water level change and the medium loss are obtained by analysis and processing, and the water level estimation value is calculated and identified to generate a control signal.

[0124] Water level control module: based on the generated control signal, dynamically control the water level.

[0125] Automatic water supplement module: control the electromagnetic valve to drive the water pump to work to supplement and discharge the liquid medium in the container assembly 11.

[0126] The specific monitoring steps of the water level monitoring system are as follows:

[0127] Obtain the real-time water level of the liquid medium: obtain the water level value data of multiple positions in the container assembly 11 through the sensor, sum the water level value data to obtain the average value, and obtain the real-time water level HA of the liquid medium.

[0128] Obtain the water level influence data: the water level influence data includes the volume influence of the material sheet and the heat influence of the material sheet.

[0129] Wherein, the volume influence of the material sheet is the height of the water level rising after the material sheet enters the liquid medium, and the heat influence of the material sheet is the height of the water level falling when the material sheet enters the liquid medium and increases the evaporation rate, and the liquid leaves the water surface in the form of steam;

[0130] The water level influence data acquisition process is:

[0131] The size of the material sheet is acquired, including the length value, width value and height value of the material sheet, and the acquired length value, width value and height value are calculated into the volume value VX of the material sheet through the volume formula;

[0132] The length value and width value of the container assembly 11 are acquired, and the bottom area SX of the container assembly 11 is calculated through the area formula;

[0133] The formula HX=VX / SX is substituted to obtain the height HX of the influence of the volume of the material sheet on the water level of the liquid medium;

[0134] The heat of the material sheet after austenitizing heating is acquired through the heat formula Q=C*M*Δt, wherein Q is the absorbed heat, M is the mass of the object, C is the specific heat capacity of the substance, and ΔT is the temperature change amount;

[0135] The formula Q=M1*L is substituted, wherein Q is the total energy, M1 is the mass of the liquid medium evaporation, and L is the evaporation latent heat of the liquid;

[0136] The evaporation latent heat is a physical property of a substance, which is not only related to the nature of the substance itself, but also a function of temperature, and the evaporation latent heat value at a specific temperature is usually given in the physical property data table of the substance;

[0137] The mass M1 of the liquid medium evaporation can be obtained through the above formulas Q=C*M*Δt and Q=M1*L, the density of the liquid medium is calculated and processed, and the evaporation volume VY of the liquid medium is obtained;

[0138] The formula HY=VY / SX is substituted to obtain the height HY of the influence of the heat of the material sheet on the water level of the liquid medium;

[0139] The formula HH=HA+HX-HY is substituted to obtain the water level estimation value HH;

[0140] The water level estimation value HH is compared with the water level threshold range [HM-HN], wherein the water level threshold range is 0-300mm above the top surface of the lower forming die 21;

[0141] If HH∈[HM-HN], a normal production signal is generated;

[0142] If HH<HM, a water replenishment signal is generated;

[0143] If HH>HN, a drainage signal is generated;

[0144] Based on the above drainage signal, the electromagnetic valve drives the water pump to pump out the liquid medium from the inside of the container assembly 11, so that the water level of the liquid medium is kept within the water level threshold range [HM-HN];

[0145] Based on the above water replenishment signal, the electromagnetic valve drives the water pump to replenish the liquid medium to the inside of the container assembly 11, while analyzing the influence factor of the water replenishment time, and based on the influence factor, the speed of water replenishment is adjusted to control the water replenishment time within the time period from the completion of heating to the transfer of the material sheet to the material support 22;

[0146] The minimum value of the height of the liquid medium required to be replenished is Hmin=HM-HH, and the maximum value of the height of the liquid medium required to be replenished is Hmax=HN-HH;

[0147] The influence factor of the water replenishment time is obtained by processing the material sheet space transfer time ratio and the material sheet water body transfer time ratio;

[0148] The longer the material sheet space transfer time, the greater the heat consumption of the material sheet, causing the water level to change due to evaporation factors, affecting the estimated water level. The shorter the material sheet water body transfer time, the greater the speed at which the material sheet is placed by the material loading manipulator, the greater the force of the material sheet on the liquid, resulting in a slower time for the water level to stabilize, affecting the start time of the soaking;

[0149] The material sheet space transfer time ratio is the ratio of the time T1 required by the material loading manipulator to transfer the heated material sheet to the upper side of the container assembly 11 to the space transfer standard value T2;

[0150] The material sheet water body transfer time ratio is the ratio of the time T3 at which the material loading manipulator places the material sheet on the material support 22 to the water body transfer standard value T4;

[0151] The influence factor of the water replenishment time is K=T1 / T2+T3 / T4, K is the influence factor of the water replenishment time;

[0152] According to the formula And Where Tx is the standard time of the time period from the completion of heating of the material sheet by the material loading manipulator to the placement of the material sheet into the liquid medium, which is an experienced value of the worker;

[0153] Based on the above formula, when the influence factor of the water replenishment time changes, the minimum value of the water replenishment speed is Vx, and the maximum value of the water replenishment speed is Vy, so that the water replenishment time is close to the standard time Tx by adjusting the water replenishment speed.

[0154] Example Five

[0155] Referring to FIG. 1-6, based on the above-mentioned embodiment one and embodiment two, the present application is a kind of hot forming steel's immersion stamping method, and the present embodiment is one of the examples:

[0156] The galvanized sheet material is selected, the substrate is conventional 22MnB5, the plate thickness is 1.8mm, and the galvanized layer thickness is 15μm;

[0157] The prepared galvanized sheet is grabbed by the material taking manipulator and is sent to the furnace for heating at 900 DEG C, and the heating time is 330s, and the nitrogen protection is closed during heating;

[0158] After the sheet is heated, the material taking manipulator is operated according to the debugging program to transport the sheet into the container;

[0159] The container contains water and 100ml rust-proof oil, and the water level is controlled at 50mm of the forming top surface, and the immersion precooling is 4s;

[0160] Meanwhile, the press is pressed, first fast and then slow, the holding pressure during forming is 800 tons, the holding time is 10s, and after the holding is finished;

[0161] The galvanized sheet hot-pressed part is ejected from the water surface by the mold ejection system, and the discharging manipulator equipped with the visual error prevention system is taken out according to the set program.

[0162] The produced part result is as follows:

[0163] The metallographic observation is as shown in the following FIG. 4, the substrate is martensite structure, the plating layer thickness is between 20-30μm, and no microcrack is found;

[0164] Three positions are taken on the part, and the strength result is as shown in the following FIG. 5, and the elongation is as shown in the following FIG. 6, which meets the requirements of tensile strength >1300Mpa and elongation >5%.

[0165] Embodiment six

[0166] Referring to FIG. 1-3, the present application is a kind of hot forming steel's immersion stamping device, comprising:

[0167] The immersion module 1, the forming module 2, the die seat module 3 and the ejection module 4;

[0168] The lower forming public 21 of the mold is immersed by the immersion module 1, and the temperature of the lower forming public 21 of the mold is adjusted by adjusting the temperature of the liquid medium;

[0169] The immersion module 1 includes a container assembly 11, and a plurality of heating rods 12 are arranged in the container assembly 11.

[0170] The tank assembly 11 comprises four groups of tank side plates 111, which are arranged in a rectangular shape, and two groups of tank upper cover plates 112 are arranged on the upper side of the four groups of tank side plates 111, and a tank bottom plate 113 is arranged on the lower side of the four groups of tank side plates 111;

[0171] It should be noted that, as shown in FIG. 1, the four tank side plates 111 and the tank bottom plate 113 form a box structure, the tank upper cover plates 112 are symmetrically arranged and fixed on the tank side plates 111, so that liquid medium can be placed inside for soaking the lower forming male 21;

[0172] The heat insulation plate assembly 14 comprises heat insulation side plates 141 arranged on the outer surface of the tank side plates 111, and a heat insulation bottom plate 142 is arranged on the lower side of the tank bottom plate 113;

[0173] By arranging the heat insulation plate assembly 14, the heat insulation side plates 141 are arranged on the outer side of the tank side plates 111, and the heat insulation bottom plate 142 is arranged on the lower side of the tank bottom plate 113, so as to insulate the tank assembly 11 and reduce the harm to workers and other workpieces caused by the high temperature of the tank assembly 11;

[0174] The outer surface of the heat insulation side plate 141 is fixedly connected with the junction box 13;

[0175] The junction box 13 is arranged in multiple groups and arranged in a linear array;

[0176] The junction box 13 is connected with the temperature control electric cabinet box 16 through a connecting line;

[0177] The temperature control system is arranged in the temperature control electric cabinet box 16, and the liquid medium in the tank assembly 11 is temperature-controlled by the temperature control system during production, so that the temperature can be maintained within the range of 80-100℃;

[0178] The forming module 2 comprises two groups of lower forming males 21 arranged on the upper side of the tank bottom plate 113, and a material supporting frame 22 is arranged on both sides of the two groups of lower forming males 21, and a plurality of positioning pins 23 are arranged on the outer side of the end portion of the two groups of lower forming males 21;

[0179] The two groups of lower forming males 21 are symmetrically arranged, the material supporting frame 22 is arranged at equal intervals and used for supporting the material sheet, and the positioning pins 23 are used for limiting the material sheet;

[0180] The mold base module 3 comprises a lower mold base 31 and a supporting block 32, and a liquid pipe 15 is arranged on one side of the lower mold base 31 and communicates with the inside of the tank assembly 11;

[0181] Liquid port 15, for putting liquid medium into the inside of the tank assembly 11, and when it is needed to change the liquid medium, it is extracted through the liquid port 15 again;

[0182] The ejection module 4 includes a plurality of sets of ejector pins 41 arranged on the top surface of the lower forming punch 21, the ejector pins 41 are controlled to rise and fall by the oil cylinder ejection assembly 42, the oil cylinder ejection assembly 42 includes a plurality of sets of oil cylinder assemblies 422 and soft spring oil pipes 421;

[0183] The ejection module 4 is arranged to eject the formed material sheet after the material sheet is punched, by controlling the oil cylinder assemblies 422 to press the soft spring oil pipes 421, the elastic deformation of the soft spring oil pipes 421 and the transmission of the internal fluid pressure are used to apply force to the ejector pins 41, so that the formed material sheet on the ejector pins 41 is ejected from the lower forming punch 21, which is convenient for the material loading robot to take the material.

[0184] The above has carried on the detailed description to one embodiment of the application, but the content described is only the preferred embodiment of the application, and cannot be considered to limit the implementation range of the application. Any equivalent change and improvement made according to the application scope should still belong to the patent coverage range of the application.

Claims

1. A dip-pressing method for hot-formed steel, characterized in that, Includes the following steps: Step 1: Transport the prepared sheet material into the furnace for austenitizing heating, wherein the sheet material is hot-formed steel material; Step 2: Immerse the lower forming part (21) in the liquid medium of the container assembly, and place the material sheet obtained in Step 1 on the material support frame (22), with the top of the material support frame (22) below the liquid surface of the liquid medium; Step 3: The upper mold presses down to fit the lower mold, and the material sheet is pressed and formed. Step 4: After the pressure holding is completed, the hot-pressed part is ejected from the liquid medium by the ejection module (4) and the hot-pressed part is taken out.

2. The immersion stamping method for hot-formed steel according to claim 1, characterized in that, The material sheet is transported into the furnace by the material handling robot, the heated material sheet is placed on the material support frame (22) by the material loading robot, and the hot-pressed part is taken out by the material unloading robot.

3. The immersion stamping method for hot-formed steel according to claim 1, characterized in that, Oil is added to the surface of the liquid medium. The oil includes industrial rust-preventive oil and lubricating oil, and the oil content is set to 100-200ml.

4. The immersion stamping method for hot-formed steel according to claim 1, characterized in that, The container assembly (11) is provided with multiple sets of heating rods (12), and the multiple sets of heating rods (12) are arranged at equal intervals.

5. The immersion stamping method for hot-formed steel according to claim 1, characterized in that, An error prevention system is installed in the unloading area, which includes a weight sensing system installed on the unloading robot arm.

6. The immersion stamping method for hot-formed steel according to claim 1, characterized in that, The thickness of the sheet material is 1-14mm.

7. The immersion stamping method for hot-formed steel according to claim 1, characterized in that, The liquid level of the liquid medium is controlled to be 0-300mm above the top surface of the lower forming male.

8. The immersion stamping method for hot-formed steel according to claim 1, characterized in that, The liquid medium includes water or a mixture of water and a slow coolant, with the ratio of slow coolant to water controlled between 1:5 and 1:

10.

9. The immersion stamping method for hot-formed steel according to claim 1, characterized in that, In step two, the material sheet is partially immersed in the liquid medium.

10. The immersion stamping method for hot-formed steel according to claim 9, characterized in that, In step two, the soaking time of the material in the container is 3-5 seconds.

11. The immersion stamping method for hot-formed steel according to claim 1, characterized in that, In step three, the speed at which the upper mold presses down is initially fast and then slows down.

12. The immersion stamping method for hot-formed steel according to claim 1, characterized in that, In step three, the holding pressure during the sheet forming process is between 4000-20000KN, and the holding time is based on the following formula: T2=t*5+1, where T2 is the holding time and t is the sheet thickness.

13. The immersion stamping method for hot-formed steel according to claim 1, characterized in that, The water level during the stamping process is monitored by a water level monitoring system, and automatic water replenishment is performed based on the monitoring results. The steps are as follows: Check and obtain the real-time water level value of the liquid medium: The water level data of multiple locations inside the tank assembly are obtained through sensors, and the average value of these water level data is summed to obtain the real-time water level value HA of the liquid medium. Obtaining water level impact data: Water level impact data includes the impact of material volume and material heat; Among them, the volume effect of the material sheet is the height by which the water level rises after the material sheet enters the liquid medium, and the heat effect of the material sheet is the height by which the water level drops when the material sheet enters the liquid medium, as the liquid leaves the water surface in the form of steam. The process of obtaining water level impact data is as follows: Obtain the dimensions of the material sheet, including its length, width, and height. Calculate the volume VX of the material sheet using the volume formula based on the obtained length, width, and height values. Obtain the length and width values ​​of the container assembly, and calculate the bottom area SX of the container assembly using the area formula; Substituting into the formula: HX=VX / SX, we can obtain the height HX, which shows the influence of the material volume on the liquid medium water level; The heat absorbed by the material after austenitizing heating is obtained using the formula Q = C * M * Δt, where Q is the absorbed heat, M is the mass of the material, C is the specific heat capacity of the material, and ΔT is the change in temperature. The formula Q = M1 * L is used, where Q is the total energy, M1 is the mass of the liquid medium evaporating, and L is the latent heat of vaporization of the liquid. The mass M1 of the liquid medium evaporating can be obtained by using the above formulas Q=C*M*Δt and Q=M1*L. The density of the liquid medium can be calculated and processed to obtain the evaporation volume VY of the liquid medium. Substituting into the formula: HY=VY / SX, we can obtain the effect of the material's heat on the liquid medium's water level, HY. The estimated water level HH can be obtained using the formula: HH=HA+HX-HY; Compare the estimated water level HH with the water level threshold range [HM-HN], where the water level threshold range is 0-300mm above the bottom surface of the lower forming male. If HH∈[HM-HN], then a normal production signal is generated; If HH < HM, then a water replenishment signal is generated; If HH > HN, then a drainage signal is generated; Based on the above drainage signal, the control solenoid valve drives the water pump to extract the liquid medium from the inside of the tank assembly, so that the water level of the liquid medium is maintained within the water level threshold range [HM-HN]. Based on the above water replenishment signal, the solenoid valve is controlled to drive the water pump to replenish the liquid medium into the tank assembly. At the same time, the influencing factors of the water replenishment time are analyzed, and the water replenishment speed is adjusted based on the influencing factors so that the water replenishment time is controlled within the time period after the material is heated and transferred to the material rack. The minimum height of the liquid medium to be replenished, Hmin = HM - HH, and the maximum height of the liquid medium to be replenished, Hmax = HN - HH; The influencing factor of water replenishment time was obtained by processing the ratio of material space transfer time to material water transfer time; The material sheet space transfer time ratio is the ratio of the time T1 required for the loading robot to transfer the heated material sheet to the upper side of the container assembly to the standard value T2 of space transfer. The material sheet water transfer time ratio is the ratio of the time T3 when the feeding robot places the material sheet on the support frame to the standard value T4 of water transfer. The influencing factor of water replenishment time: K = T1 / T2 + T3 / T4, where K is denoted as the influencing factor of water replenishment time; According to the formula and Where Tx is the standard time from when the feeding robot moves the material from the point of heating to when it is placed into the liquid medium. This time is the experience value of the staff. Based on the above formula, when the factors affecting the water replenishment time change, the minimum value of the water replenishment speed is Vx, and the maximum value of the water replenishment speed is Vy. By adjusting the water replenishment speed, the water replenishment time can be made close to the standard time Tx.

14. A hot-forming steel immersion stamping apparatus, characterized in that, It includes an immersion module (1), a molding module (2), a mold base module (3), and an ejection module (4); The soaking module (1) includes a container assembly (11), and the container assembly (11) is provided with multiple sets of heating rods (12); The molding module (2) includes a lower molding man (21) disposed on the upper side of the bottom plate (113) of the container, and material support racks (22) are provided on both sides of the lower molding man (21).

15. The immersion stamping apparatus for hot-formed steel according to claim 14, characterized in that, The container assembly (11) includes four sets of container side plates (111), and the four sets of container side plates (111) are arranged in a rectangular enclosure. Two sets of container top cover plates (112) are provided on the upper side of the four sets of container side plates (111), and a container bottom plate (113) is provided on the lower side of the four sets of container side plates (111).

16. The immersion stamping apparatus for hot-formed steel according to claim 15, characterized in that, The soaking module (1) also includes a heat insulation plate assembly (14) including a heat insulation side plate (141) on the outer surface of the provided container side plate (111), and a heat insulation bottom plate (142) is provided on the lower side of the heat insulation side plate (141), and the heat insulation bottom plate (142) is provided on the lower side of the container bottom plate (113). A junction box (13) is fixedly connected to the outer surface of the heat insulation side plate (141); The junction box (13) is connected to the temperature control cabinet box (16) via a connecting line.

17. The immersion stamping apparatus for hot-formed steel according to claim 14, characterized in that, The forming module (2) includes two sets of lower forming males (21) arranged on the upper side of the bottom plate (113) of the container. Both sides of the two sets of lower forming males (21) are provided with material support racks (22), and multiple sets of positioning pins (23) are provided on the outer side of the ends of the two sets of lower forming males (21).

18. The immersion stamping apparatus for hot-formed steel according to claim 14, characterized in that, The mold base module (3) includes a lower mold base (31) and a support block (32). A liquid port (15) is provided on one side of the lower mold base (31), and the liquid port (15) is connected to the interior of the container assembly (11).

19. The immersion stamping apparatus for hot-formed steel according to claim 14, characterized in that, The ejection module (4) includes multiple sets of ejector pins (41) disposed on the top surface of the lower forming die (21). The ejector pins (41) are controlled to rise and fall by a hydraulic cylinder ejection assembly (42). The hydraulic cylinder ejection assembly (42) includes multiple sets of hydraulic cylinder assemblies (422) and soft spring oil pipes (421).

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