CN116702526A - Modeling and manufacturing method of high-speed turnover plow grid bar capable of improving mechanical property and reducing resistance - Google Patents
Modeling and manufacturing method of high-speed turnover plow grid bar capable of improving mechanical property and reducing resistance Download PDFInfo
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Abstract
The invention relates to the field of manufacture of earth-penetrating parts of turnover plows, in particular to a modeling method of a high-speed turnover plowing grid capable of improving mechanical property and reducing resistance, which determines a plow body width b with the lowest working resistance, a plow shovel mounting angle epsilon and a guide curve upturned angle delta by carrying out parameter optimization, three-dimensional modeling and numerical simulation analysis on a curved surface of the high-speed turnover plowing grid ε And the parameters of the angle theta with the element line, and carrying out component optimization design and machining, normalizing, quenching and tempering treatment on the novel high-speed turnover plow grid base material to obtain the high-speed turnover plow grid with low running resistance, high yield strength, high tensile strength, high toughness and high wear resistance, wherein the high-speed turnover plow grid can haveThe high-speed impact and abrasion of soil and stones are effectively resisted, the energy consumption is reduced, and the high-speed impact and abrasion resistant composite material is expected to be widely applied to the field of agricultural machine manufacturing.
Description
Technical Field
The invention relates to the field of manufacturing of high-speed turnover plow penetration components, in particular to a modeling and manufacturing method of a high-speed turnover plow grid bar capable of improving mechanical properties and reducing resistance.
Background
In recent years, with the continuous acceleration of the running speed of the plow body and the rapid development of new energy tractors, the reduction of the resistance of the plow body and the reduction of the energy consumption become a necessary trend under the condition of keeping the cultivation quality of the heavy high-speed turnover plow. The main plow body is used as a core component of the high-speed turnover plow and mainly comprises a plow tip, a plow shovel, a chest plate and grid bars. Wherein, the grid part mainly plays the soil turning effect, often appears the circumstances of fracture inefficacy because of bearing soil and stone's high-speed impact. Therefore, the turnover plow grid bar in the high-speed service environment not only needs good curved surface parameter design to obtain lower running resistance, but also needs to meet the high-strength and toughness matching performance to resist the impact of soil and stones.
In order to solve the problems, a large number of students adopt a plow body curved surface parameter optimization method for the high-speed turnover plow grid bar so as to reduce the running resistance of the plow body and improve the strength of the grid bar by properly improving the heat treatment process parameters of the materials. The horizontal straight line design method of the plow body curved surface is the most widely used method so far. The principle of forming a plow curved surface by a horizontal straight element line method is to adopt a three-dimensional coordinate system, move the straight element line along a quasi-line (a track line or a lead) and be always parallel to an XOY coordinate plane, and continuously change the included angle (element line angle) between the straight element line and a ZOX coordinate plane to form the curved surface. However, the use of only horizontal and straight line methods to optimize the plow curved surface parameters does not effectively describe the actual soil turning operation process, and it is not possible to quantitatively analyze the optimized plow working resistance due to the lack of interaction parameters between the soil and the plow. In addition, for boron steel widely applied to high-speed turnover plow bars, a quenching-tempering process is generally adopted by turnover plow manufacturing enterprises to carry out strengthening treatment on the boron steel, so that a turnover plow bar component consisting of lath martensite structures with the content of more than 98% can be obtained. Therefore, the phase structure composition of the boron steel for the grid bar cannot be changed only by optimizing the heat treatment process parameters (such as temperature and time), and the improvement of the tensile strength, the toughness and the wear resistance of the grid bar is very limited. In summary, the conventional horizontal straight element line design method and heat treatment process parameter improvement method are adopted to reduce the running resistance of the plow body and improve the tensile strength, toughness and wear resistance of the grid, and the idea that the conventional turnover plow cannot obviously meet the requirements of low running resistance and high service performance (particularly high tensile strength, high toughness and high wear resistance) in a high-speed service environment.
Disclosure of Invention
In view of the above, the present inventors have provided a method of modeling and manufacturing a high-speed turndown plow blade that improves mechanical properties and reduces drag.
Firstly, the invention determines the optimal curved surface parameters of the low-resistance grid through a horizontal straight element line design method, UG modeling and ANSYS simulation analysis. Compared with the traditional grid curved surface optimization method, the method comprehensively considers factors such as soil parameters, grid material parameters, contact relation between a plow body and soil and the like through UG modeling and ANSYS simulation analysis, and greatly improves the working efficiency of the plow body curved surface optimization process and the feasibility of an optimization scheme. On the basis, the invention adds proper amounts of Al, nb and Cu elements on the basis of the component design of the 28MnB5 steel for the prior turnplow grid bars, and the novel 28MnB5-M steel with fine grains and uniform distribution is obtained by smelting by utilizing a vacuum induction smelting furnace. Wherein, al element can generate highly finely divided super-microscopic oxide particles which are dispersed in steel to prevent the growth of grains. The Nb element can produce highly dispersed, strong carbide NbC, which can further prevent grain growth. The Cu element can not only improve the hardenability of steel by enhancing the stability of austenite, but also improve the corrosion resistance of steel. The alloying thinking effectively improves the defects of coarse grains and uneven distribution of the original 28MnB5 steel, and provides high-quality raw material supply for the subsequent manufacture of high-strength turnover plow bars. In addition, the invention adds thermoforming and normalizing processes (machining-thermoforming-normalizing-quenching-tempering-shot-blasting-plastic) to the grid part prepared based on the low resistance grid modeling scheme and the high quality 28MnB5-M steel. The hot forming is a process of synchronously forming the grid blank heated to an austenitizing state by using a stamping die, so that the defect that the grid blank generates microcracks at large deformation positions in cold processing can be effectively avoided, the working load of a press in the grid blank forming process can be greatly reduced, and the energy conservation is facilitated. In addition, the normalizing process can uniformly distribute chemical elements in the 28MnB5-M steel and reduce component segregation, so that the structure of the 28MnB5-M steel is further refined, and the content of the strip-shaped structure in the steel is reduced, so that the good toughness matching and the high wear resistance of the turnover plow grid part are realized. The technical method effectively realizes the manufacture of the novel high-speed turnover plow grid bar with low running resistance, high yield strength, high tensile strength, high toughness and high wear resistance, and is more beneficial to achieving the purpose of reducing the energy consumption of the tractor. The technical method used in the invention has high feasibility, easy popularization and low cost, and is expected to be widely applied in the field of agricultural machinery manufacturing.
The invention relates to the field of manufacturing of high-strength turnover plow components, and provides a modeling and manufacturing method of a high-speed turnover plow grid bar capable of improving mechanical properties and reducing resistance. The grid part prepared by the method has the characteristics of low running resistance, good toughness matching and high wear resistance, can effectively solve the problems of overlarge resistance and easy fracture and failure existing in the operation process of the conventional high-speed turnover plow grid, and is expected to be widely applied to the manufacturing field of soil-contact parts of agricultural machinery.
Drawings
FIG. 1 shows an assembly view of a grid assembly according to one embodiment of the invention;
FIG. 2 shows a photomicrograph of a high-speed inverted plow grid assembly prepared in accordance with a first embodiment of the invention;
FIG. 3 shows an X-ray diffraction pattern of a high-speed turn-down plow grid bar assembly prepared in accordance with a first embodiment of the present invention;
FIG. 4 shows EBSD test results of a high speed flip plow grid assembly prepared in accordance with the first embodiment of the present invention;
FIG. 5 shows the results of mechanical testing of the high speed turndown plow grid assembly prepared in accordance with the first embodiment of the invention;
FIG. 6 shows a mechanical comparison of a high speed turn plow grid assembly prepared in accordance with a first embodiment of the present invention with an existing grid;
FIG. 7 shows a photomicrograph of a high-speed inverted plow grid assembly prepared in accordance with a second embodiment of the invention;
FIG. 8 shows an X-ray diffraction pattern of a high-speed inverted plow grid assembly prepared in accordance with a second embodiment of the invention;
FIG. 9 shows EBSD test results of a high speed flip plow grid assembly prepared in accordance with the second embodiment of the present invention;
FIG. 10 shows the mechanical test results of a high speed turndown plow grid assembly prepared in accordance with a second embodiment of the invention;
FIG. 11 shows a mechanical comparison of a high speed turn plow grid assembly prepared in accordance with a second embodiment of the present invention with an existing grid;
FIG. 12 shows a photomicrograph of a high-speed inverted plow grid assembly prepared in accordance with a third embodiment of the invention;
FIG. 13 shows an X-ray diffraction pattern of a high-speed turn-down plow grid assembly prepared in accordance with a third embodiment of the invention;
FIG. 14 shows EBSD test results of a high speed flip plow grid assembly prepared in accordance with the third embodiment of the present invention;
FIG. 15 shows the results of mechanical testing of a high speed turndown plow grid assembly prepared in accordance with a third embodiment of the invention;
fig. 16 shows the mechanical properties of a high speed turn plow grid assembly prepared in accordance with a third embodiment of the invention in comparison to prior grids.
Detailed Description
According to one aspect of the invention, in order to solve the problems of overlarge resistance and insufficient service life of the existing high-speed turnover plow grid bar in the service process, the invention provides a modeling and manufacturing method of the high-speed turnover plow grid bar capable of improving mechanical properties and reducing resistance. Firstly, the invention determines the optimal curved surface parameters of the low-resistance grid through a horizontal straight element line design method, UG modeling and ANSYS simulation analysis. Compared with the traditional grid curved surface optimization method, the method comprehensively considers factors such as soil parameters, grid material parameters, contact relation between a plow body and soil and the like through UG modeling and ANSYS simulation analysis, and greatly improves the working efficiency of the plow body curved surface optimization process and the feasibility of an optimization scheme. On the basis, the invention adds proper amounts of Al, nb and Cu elements on the basis of the component design of the 28MnB5 steel for the prior turnplow grid bars, and the novel 28MnB5-M steel with fine grains and uniform distribution is obtained by smelting by utilizing a vacuum induction smelting furnace. Wherein, al element can generate highly finely divided super-microscopic oxide particles which are dispersed in steel to prevent the growth of grains. The Nb element can produce highly dispersed, strong carbide NbC, which can further prevent grain growth. The Cu element can not only improve the hardenability of steel by enhancing the stability of austenite, but also improve the corrosion resistance of steel. The alloying thinking effectively improves the defects of coarse grains and uneven distribution of the original 28MnB5 steel, and provides high-quality raw material supply for the subsequent manufacture of high-strength turnover plow bars. In addition, the invention adds thermoforming and normalizing processes (machining-thermoforming-normalizing-quenching-tempering-shot-blasting-plastic) to the grid part prepared based on the low resistance grid modeling scheme and the high quality 28MnB5-M steel. The hot forming is a process of synchronously forming the grid blank heated to an austenitizing state by using a stamping die, so that the defect that the grid blank generates microcracks at large deformation positions in cold processing can be effectively avoided, the working load of a press in the grid blank forming process can be greatly reduced, and the energy conservation is facilitated. In addition, the normalizing process can uniformly distribute chemical elements in the 28MnB5-M steel and reduce component segregation, so that the structure of the 28MnB5-M steel is further refined, and the content of the strip-shaped structure in the steel is reduced, so that the good toughness matching and the high wear resistance of the turnover plow grid part are realized. The technical method effectively realizes the manufacture of the novel high-speed turnover plow grid bar with low running resistance, good toughness matching and high wear resistance, and is more beneficial to achieving the purpose of reducing the energy consumption of the tractor. The method is expected to provide a feasible technical scheme for realizing the safety and long-service life of the soil contact part of the agricultural machinery.
The modeling and manufacturing method of the high-speed turnover plow grid bar capable of improving mechanical property and reducing resistance according to one embodiment of the invention comprises the following steps:
step A): and optimizing the grid curved surface by using a horizontal straight element line design method. In order to improve the soil turning capacity of the plow body, reduce the friction between the grid bars and soil and reduce the loss of the plow body, the key parameters of the curved surface of the grid bars of the turnover plow are calculated according to the invention according to the method 1-3. Wherein, the width b of the plow body is generally 640 mm-700 mm; the value range of the plow shovel installation angle epsilon is 20-30 degrees, and the guide curve upturned soil angle delta is formed ε Generally between 5 and 11 degrees, C 1 Is constant and is generally between 1.0 and 1.8. Calculating the value range of the opening degree l of the guide curve by 1-3 to obtain the value range of 308-458 mm, the value range of the height h of the guide curve is 550-870 mm, and the value range of the included angle omega of the tangent line of the end point is 105-109 degrees;
l＝C 1 b(cosΔε-sinε) (1)
step B): establishing a plow three-dimensional model by UG software, which comprises
B1 Selecting reference planes and respectively drawing a share blade line and a curve sketch;
b2 Combining the grid curved surface parameters in the step A, and drawing a horizontal straight element line according to the element line number in the formula (4) and an element line angle calculation formula corresponding to the element line number;
b3 Drawing a front view of the curved surface of the plow body, and projecting the front view of the curved surface of the plow body to obtain a closed space curve;
B4 Cutting out the curved surface of the plow body by using a cutting command, changing the curved surface of the plow body into a three-dimensional solid shape (shown in figure 1) by using a stretching command, and deriving a stl model file;
wherein:
n is the element wire number; θ is the angle of the element line; θ m And theta n The element line angles when the element line numbers are m and n are respectively; θ 0 For the initial line angle, 36-45 degrees are generally adopted; θ max And theta min Respectively maximum and minimum element line angles; delta z Is the distance between the element lines;
step C): performing ANSYS simulation early-stage preparation, specifically comprising the following steps:
setting soil material attribute parameters: the soil density is 1.76-1.78X103 kg/m 3 The elastic modulus is 4.3-4.5X107 Pa, the Poisson ratio is 0.33-0.35, the yield stress is 8.3-8.5X105 Pa, the tangential modulus is 1.0-1.2X106 Pa, the failure strain is 0.6-0.8, and the strain rate is 4% -6%; setting the characteristic parameters of the turnover plow grid material: the density is 7.79-7.81 multiplied by 10 < -6 > kg/mm 3 The elastic modulus is 2.2-2.4X105N/mm 2 The Poisson ratio is 0.2-0.4;
setting the contact mode between the curved surface of the plow body and the upturned soil to be automatic contact of surface erosion, and the step D): performing an analog simulation, including:
b, importing the stl model file in the step B into the ANSYS simulation environment built in the step C, and setting the running speed of the plow body part to be 0.36-0.38 m/s, wherein the advancing direction is the positive direction of the X axis;
Entering simulation setting, wherein the set time step and the simulation time are 10s in total;
starting simulation, obtaining average resistance value of plow body component after simulation is completed,
step E): preparing a novel 28MnB5-M steel, comprising:
based on the component design of the existing 28MnB5 steel, adding 0.05-0.11% of Nb and 0.04-0.10% of Al (see Table 1 for details), smelting alloy by adopting a vacuum induction furnace, casting into 200kg of cast ingot, and forging into a hot-rolled blank of 500mm multiplied by 1000mm multiplied by 50 mm;
heating the hot rolled blank to 1100-1200 ℃, preserving heat for 1.8-2.0 h, discharging, and performing 3-pass rolling, wherein the finishing temperature is 880-920 ℃, and the plate thickness after rolling is 12mm;
water-cooling the plate after finish rolling to a set coiling temperature of 500-600 ℃, then placing the plate into a heating furnace for heat preservation for 28-30 min, and then cooling along with the furnace;
finally, pickling to remove the oxide scale on the surface of the hot rolled plate,
TABLE 1 chemical composition comparison (mass fraction,%) of novel 28MnB5-M steel and existing 28MnB5 steel
Step F): the grid blank machining method specifically comprises the following steps of:
cutting the 28MnB5-M hot rolled plate in the step E into grid blanks by using an oxygen-acetylene cutting method;
the profile of the grid blank is finished by a milling machine,
Machining a countersunk square hole of the grid blank by using a drilling machine,
step G): carrying out hot forming, normalizing, quenching and tempering treatment on the grid bars, wherein the hot forming, normalizing, quenching and tempering treatment specifically comprises the following steps:
heating the grid blank in the step F to 940-960 ℃, and preserving heat for 1.0-1.2 h;
b, transferring the grid blank into a stamping die after heat preservation is finished, forming the grid blank into the three-dimensional solid shape required in the step B, and cooling the grid blank to room temperature in air after forming is finished;
heating the grid blank to 900-920 ℃ again, preserving heat for 0.5-0.7 h, immersing in water, and quenching to room temperature;
further transferring the quenched grid blank into a tempering furnace with the temperature of 180-200 ℃ for heat preservation for 2.0-2.4 hours, and discharging the quenched grid blank from the furnace for air cooling after heat preservation is finished;
and (3) performing shot blasting and plastic spraying treatment to obtain the high-speed turnover plow grid bar component with low running resistance, high strength, high toughness and high wear resistance.
The advantages of the invention include:
the invention provides a modeling and manufacturing method of a high-speed turnover plow grid bar capable of improving mechanical properties and reducing resistance, which comprehensively adopts a horizontal straight element line design method, UG modeling and ANSYS simulation analysis to determine the optimal curved surface parameters of the low-resistance plow grid bar. Then the components of the 28MnB5 steel for the grid bars and the manufacturing process of the grid bars are purposefully improved, and the invention has the following advantages:
(1) Compared with the prior method for optimizing the grid curved surface only through mathematical model calculation, the method is remarkably different from the prior method for optimizing the grid curved surface only through mathematical model calculation, the design parameters of the high-speed turnover plow grid part are reasonably optimized by combining a horizontal straight line design method, UG modeling and ANSYS simulation analysis method, and meanwhile, factors such as soil parameters, grid material parameters, contact relation between a plow body and soil are introduced, so that the working efficiency of the plow curved surface optimization process and the feasibility of an optimization scheme are greatly improved, the plow body running resistance is effectively reduced, and the impact force of the soil on the grid part and the oil consumption of a tractor are further reduced.
(2) The invention improves the component design of 28MnB5 steel, and the novel 28MnB5-M steel is obtained by compounding and adding 0.05 to 0.11 percent of Nb, 0.04 to 0.10 percent of Al and 0.10 to 0.20 percent of Cu element by mass percent. The characteristic that the high-fine-crushing oxide generated by the composite addition of Nb and Al can prevent the crystal grains from growing when the steel is heated is utilized, so that the strength and toughness matching degree of the novel 28MnB5-M steel after heat treatment is further improved. The Cu element can not only improve the hardenability of steel by enhancing the stability of austenite, but also improve the corrosion resistance of steel. Compared with the method of adding expensive rare earth elements, the price of Nb, al and Cu elements used in the invention is obviously reduced, and the performance also meets the requirements of industry, thus being one of the most economical and effective means for improving the performance of steel.
(3) The thermal forming, normalizing, quenching and tempering heat treatment process adopted by the invention has mature industrialization technology, can be realized on the basis of the existing production equipment, does not need to add other heat treatment equipment, and can greatly reduce the cost. Meanwhile, the structure size and uniformity of the grid part after the hot forming, normalizing, quenching and tempering treatment are obviously better than those of the traditional grid part, so that the grid part has good toughness matching performance, and the grid can be effectively ensured to bear high-speed impact of soil and stones and not to be easy to lose efficacy. Therefore, the heat treatment process adopted by the invention has higher cost performance and wide application prospect in the field of plow body manufacturing.
In summary, the modeling and manufacturing method of the high-speed turnover plow grid bar capable of improving mechanical properties and reducing resistance provided by the invention not only can effectively solve the problems of insufficient toughness matching and larger resistance existing in the operation process of the existing high-speed turnover plow grid bar, but also has the characteristics of high cost performance, and has important and wide application prospects in the field of agricultural machinery manufacturing.
In order to more clearly understand the technical features, objects and advantages of the present invention, the following embodiments will explain the technical solution of the present invention in detail, but the scope of the present invention is not limited to the following embodiments.
Example 1:
the operation steps comprise:
(1) The design and manufacture of the grid comprises:
step 1: and optimizing the grid curved surface by using a horizontal straight element line design method. In order to improve the soil turning capacity of the plow body, reduce the friction between the grid bars and soil and reduce the loss of the plow body, the key parameters of the curved surface of the grid bars of the turnover plow are calculated according to the embodiment of 5-7. Wherein the width b of the plow body is 640mm; the value of the plow shovel installation angle epsilon is 20 DEG, and the guide curve upturned angle delta is formed ε Take the value of 5 degrees, C 1 The value is 1.0. The value of the opening l of the guide curve is 308mm, the value of the height h of the guide curve is 550mm, and the value of the included angle omega of the tangent line of the end point is 105 degrees.
l＝C 1 b(cosΔε-sinε) (5)
Step 2: and establishing a plow body three-dimensional model by utilizing UG software. Firstly, selecting reference planes to respectively draw a share blade line and a curve sketch; then, drawing a horizontal straight element line by combining the element line number in the element line number and the element line angle calculation formula corresponding to the element line number in the element line number and the element line angle calculation formula; and finally, drawing a front view of the curved surface of the plow body, and projecting the front view of the curved surface of the plow body to obtain a closed space curve. On the basis, the curved surface of the plow body is cut out by utilizing a cutting command, and then the curved surface of the plow body is changed into a three-dimensional solid shape by utilizing a stretching command, and a stl model file is exported.
Wherein:
n is the element wire number; θ is the angle of the element line; θ m And theta n The element line angles when the element line numbers are m and n are respectively; θ 0 For the initial line angle, 36-45 degrees are generally adopted; θ max And theta min Respectively maximum and minimum element line angles; delta z Is the distance between the element lines;
step 3: ANSYS simulation pre-preparation. Setting soil material attribute parameters: the soil density is 1.76X103 kg/m 3 The elastic modulus is 4.3×107Pa, the Poisson ratio is 0.33, the yield stress is 8.3×105Pa, the tangent modulus is 1.0×106Pa, the failure strain is 0.6, and the strain rate is 4%; setting the characteristic parameters of the turnover plow grid material: the density is 7.79 multiplied by 10 < -6 > kg/mm 3 Elastic modulus is 2.2X105N/mm 2 Poisson's ratio is 0.2; the contact mode between the curved surface of the plow body and the upturned soil is set as automatic contact of face erosion.
Step 4: simulation is performed. Importing the stl model file in the step 2 into the ANSYS simulation environment built in the step 3, and setting the running speed of the plow body part to be 0.36m/s, wherein the advancing direction is the positive direction of the X axis; entering simulation setting, wherein the set time step and the simulation time are 10s; and (3) starting simulation, and obtaining the average resistance value of the plow body part to be 4.98kN after the simulation is completed.
Step 5: preparing novel 28MnB5-M steel. Based on the component design of the existing 28MnB5 steel, adding 0.05 percent of Nb, 0.04 percent of Al and 0.10 percent of Cu (see Table 2 for details), smelting alloy by adopting a vacuum induction furnace, casting into 200kg of cast ingot, and forging into a hot-rolled blank of 500mm multiplied by 1000mm multiplied by 50 mm; heating the blank to 1100 ℃, preserving heat for 1.8h, discharging, and performing 3-pass rolling, wherein the final rolling temperature is 880 ℃, and the plate thickness after rolling is 12mm; and (3) cooling the finally rolled plate to the set coiling temperature of 500 ℃ by water, then placing the plate into a heating furnace for heat preservation for 28min, and cooling along with the furnace. Finally, pickling to remove the oxide scale on the surface of the hot rolled plate.
Table 2 chemical composition comparison (mass fraction,%) of novel 28MnB5-M steel and existing 28MnB5 steel
Step 6: and (5) machining the grid blank. Cutting the 28MnB5-M hot rolled plate in the step 5 into grid blanks by using an oxygen-acetylene cutting method; and (3) carrying out finish machining on the shape of the grid bar by using a milling machine, and machining countersunk square holes of the grid bar by using a drilling machine.
Step 7: hot forming, normalizing, quenching and tempering the grid bars. Heating the grid blank in the step 6 to 940 ℃, and preserving heat for 1.0h; transferring the grid blank into a stamping die after heat preservation is finished, forming the grid blank into the three-dimensional solid shape required in the step 2, and cooling the grid blank to room temperature in air after forming is finished; heating the grid blank to 900 ℃, preserving heat for 0.5h, immersing in water, and quenching to room temperature; further transferring the quenched grid blank into a tempering furnace with the temperature of 180 ℃ for heat preservation for 2.0h, and discharging the quenched grid blank from the furnace for air cooling after heat preservation is finished. Then shot blasting and plastic spraying treatment are carried out to obtain the high-speed turnover plow grid bar component with low running resistance, high strength, high toughness and high wear resistance.
(2) Alloy detection
The novel 28MnB5-M grid microstructure is observed by using a FEI Nova Nano 450 field emission scanning electron microscope and an optical microscope, and samples are sequentially subjected to mosaic, grinding and polishing before the test. FIG. 2 is a scanning electron microscope photograph of the novel 28MnB5-M grid of this example. It can be seen that the structure of the 28MnB5-M grid consists mainly of lath martensite of small size and uniformly distributed, with an average length of about 4.6 μm.
The phase composition of the novel 28MnB5-M grid material is analyzed by adopting an X-ray diffraction (XRD), the X-ray diffraction is tested by using a Japan-Smartlab XRD instrument, a Co target is selected as a target, the scanning speed is 4 degrees/min, and the scanning angle is 30 degrees-110 degrees. Fig. 3 shows the phase composition of the novel 28MnB5-M grid material of this example. It can be seen that the novel 28MnB5-M grid material consists mainly of the alpha phase.
After mechanical grinding and polishing of the 28MnB5-M grid sample, electropolishing was performed at room temperature using an electropolishing solution with a ratio of perchloric acid: alcohol=1:9 (volume ratio), and martensitic orientation imaging analysis was performed on a Gemini SEM 300-type field emission scanning electron microscope equipped with an Oxford-EBSD imaging system, with a scanning step size of 0.06 μm. FIG. 4 shows the EBSD test results of the 28MnB5-M grid sample, and it can be seen that the interface between the martensite blocks consists essentially of high angle grain boundaries, and the internal structure interface of the Martensitic blocks consists essentially of low angle grain boundaries and subgrain boundaries. The subgrain boundary content therein was as high as 37.8%, which indicates that this example contains a large amount of lath martensite of fine size.
The novel 28MnB5-M grid bar was subjected to room temperature tensile testing on an Instron-8801 tensile testing machine, wherein the tensile sample is a standard 'dog bone shaped' sample cut from the core of the grid bar along the length direction, the gauge length is 25mm, the surface and the section of the tensile sample are required to be polished before the testing to remove oxide scales and cutting marks, the strain value of the sample in the tensile process is measured by an electronic extensometer during the testing, and the strain rate is 1 multiplied by 10 -3 s -1 . Fig. 5 shows the stress-strain curve of the novel 28MnB5-M grid of this example during stretching. It can be seen that the yield strength of the novel 28MnB5-M grid is 1308MPa and the tensile strength is 1608MPa. This shows that the novel 28MnB5-M grid achieves high yield strength and highTensile strength.
The impact room temperature test was performed on the novel 28MnB5-M grid using an NI300 impact tester, using a standard Charpy V-notch specimen cut from the grid core in the length direction, with a specification of 55X 10mm. Fig. 5 shows the impact test results of the novel 28MnB5-M grid of this example. It can be seen that the impact absorption power of the novel 28MnB5-M grid is 56.0J, and the combination tensile strength data analysis shows that the novel 28MnB5-M grid realizes good toughness matching.
Under the room temperature condition, the novel 28MnB5-M grid bar is tested by adopting an MFT-R4000 type high-speed reciprocating frictional wear tester, zrO ceramic balls with the size of phi 4mm are selected as friction pairs, the loading force is 20N, the stroke is 10mm, the time is 0.5h, and a high-precision balance (the precision is ten thousandth) is used for weighing the weight loss of a sample after the frictional wear test is finished as the wear amount. Fig. 5 shows the abrasion loss test results of the novel 28MnB5-M grid material of this example. It can be seen that the abrasion loss of the novel 28MnB5-M grid material is 1.5mg.
Through the above tests and characterization, the novel 28MnB5-M grid part of the present embodiment can be found to have good toughness matching performance. In addition, the novel 28MnB5-M grid bar after the curved surface design parameters are optimized also has the characteristic of low resistance, and is expected to be applied to the fields of agricultural machinery, advanced industry and the like.
The mechanical performance parameter pairs of the novel 28MnB5-M grid and the existing grid of the embodiment are shown in FIG. 6. As can be seen from fig. 6, the novel 28MnB5-M grid of this example was significantly higher in yield strength (fig. 6 a), tensile strength (fig. 6 b) and toughness (fig. 6 c) than the conventional grid, and the running resistance (fig. 6 d) during operation was also reduced.
Example 2:
the operation steps comprise:
(1) The design and manufacture of the grid comprises:
step 1: and optimizing the grid curved surface by using a horizontal straight element line design method. In order to improve the soil turning capacity of the plow body, reduce the friction between the grid bars and soil and reduce the loss of the plow body, the embodiment is based onAnd calculating the key parameters of the curved surface of the turnover plow grid bar according to the formulas 9-11. Wherein the width b of the plow body is 670mm; the value of the plow shovel installation angle epsilon is 25 DEG, and the guide curve upturned angle delta is formed ε The value is 8 degrees, C 1 The value is 1.4. The value of the opening degree l of the guide curve is 383mm, the value of the height h of the guide curve is 710mm, and the value of the included angle omega of the tangent line of the end point is 107 degrees.
l＝C 1 b(cosΔε-sinε) (9)
Step 2: and establishing a plow body three-dimensional model by utilizing UG software. Firstly, selecting reference planes to respectively draw a share blade line and a curve sketch; then, drawing a horizontal straight element line by combining the element line number in the element line number and the element line angle calculation formula corresponding to the element line number in the element line number and the element line angle calculation formula; and finally, drawing a front view of the curved surface of the plow body, and projecting the front view of the curved surface of the plow body to obtain a closed space curve. On the basis, the curved surface of the plow body is cut out by utilizing a cutting command, and then the curved surface of the plow body is changed into a three-dimensional solid shape by utilizing a stretching command, and a stl model file is exported.
Wherein:
n is the element wire number; θ is the angle of the element line; θ m And theta n The element line angles when the element line numbers are m and n are respectively; θ 0 For the initial line angle, 36-45 degrees are generally adopted; θ max And theta min Respectively maximum and minimum element line angles; delta z Is the distance between the element lines;
step 3: ANSYS simulation pre-preparation. Setting soil material attribute parameters: soil density of 1.77×103kg/m 3 The elastic modulus is 4.4X107 Pa, the Poisson ratio is 0.34, the yield stress is 8.4X105 Pa, the tangent modulus is 1.1X106 Pa, the failure strain is 0.7, and the strain rate is 5%; setting the characteristic parameters of the turnover plow grid material: the density is 7.80 multiplied by 10 < -6 > kg/mm 3 Elastic modulus is 2.3X105N/mm 2 Poisson's ratio is 0.3; the contact mode between the curved surface of the plow body and the upturned soil is set as automatic contact of face erosion.
Step 4: simulation is performed. Importing the stl model file in the step 2 into the ANSYS simulation environment built in the step 3, and setting the running speed of the plow body part to be 0.37m/s, wherein the advancing direction is the positive direction of the X axis; entering simulation setting, wherein the set time step and the simulation time are 10s; and starting simulation, and obtaining the average resistance value of the plow body part to be 4.81kN after the simulation is completed.
Step 5: preparing novel 28MnB5-M steel. Based on the component design of the existing 28MnB5 steel, adding 0.08 percent of Nb, 0.07 percent of Al and 0.15 percent of Cu (see Table 3 for details), smelting alloy by adopting a vacuum induction furnace, casting into 200kg of cast ingot, and forging into a hot-rolled blank of 500mm multiplied by 1000mm multiplied by 50 mm; heating the blank to 1150 ℃, preserving heat for 1.9h, discharging, performing 3-pass rolling, wherein the final rolling temperature is 900 ℃, and the plate thickness after rolling is 12mm; and (3) cooling the finally rolled plate to the set coiling temperature of 550 ℃ by water, then placing the plate into a heating furnace for heat preservation for 29min, and cooling along with the furnace. Finally, pickling to remove the oxide scale on the surface of the hot rolled plate.
TABLE 3 chemical composition comparison (mass fraction,%) of novel 28MnB5-M steel and existing 28MnB5 steel
Step 6: and (5) machining the grid blank. Cutting the 28MnB5-M hot rolled plate in the step 5 into grid blanks by using an oxygen-acetylene cutting method; and (3) carrying out finish machining on the shape of the grid bar by using a milling machine, and machining countersunk square holes of the grid bar by using a drilling machine.
Step 7: hot forming, normalizing, quenching and tempering the grid bars. Heating the grid blank in the step 6 to 950 ℃, and preserving heat for 1.1h; transferring the grid blank into a stamping die after heat preservation is finished, forming the grid blank into the three-dimensional solid shape required in the step 2, and cooling the grid blank to room temperature in air after forming is finished; heating the grid blank to 910 ℃ again, preserving heat for 0.6h, immersing in water, and quenching to room temperature; further transferring the quenched grid blank into a tempering furnace with the temperature of 190 ℃ for heat preservation for 2.2 hours, and discharging and air cooling after heat preservation is finished. Then shot blasting and plastic spraying treatment are carried out to obtain the high-speed turnover plow grid bar component with low running resistance, high strength, high toughness and high wear resistance.
(2) Alloy detection
The novel 28MnB5-M grid microstructure is observed by using a FEI Nova Nano 450 field emission scanning electron microscope and an optical microscope, and samples are sequentially subjected to mosaic, grinding and polishing before the test. FIG. 7 is a scanning electron microscope photograph of the novel 28MnB5-M grid of this example. It can be seen that the structure of the 28MnB5-M grid consists mainly of lath martensite of small size and uniformly distributed, with an average length of about 4.3 μm.
The phase composition of the novel 28MnB5-M grid material is analyzed by adopting an X-ray diffraction (XRD), the X-ray diffraction is tested by using a Japan-Smartlab XRD instrument, a Co target is selected as a target, the scanning speed is 4 degrees/min, and the scanning angle is 30 degrees-110 degrees. Fig. 8 shows the phase composition of the novel 28MnB5-M grid material of this example. It can be seen that the novel 28MnB5-M grid material consists mainly of the alpha phase.
After mechanical grinding and polishing of the 28MnB5-M grid sample, electropolishing was performed at room temperature using an electropolishing solution with a ratio of perchloric acid: alcohol=1:9 (volume ratio), and martensitic orientation imaging analysis was performed on a Gemini SEM 300-type field emission scanning electron microscope equipped with an Oxford-EBSD imaging system, with a scanning step size of 0.06 μm. FIG. 9 shows the EBSD test results of the 28MnB5-M grid sample, and it can be seen that the interface between the martensite blocks consists essentially of high angle grain boundaries, and the internal structure interface of the Martensitic blocks consists essentially of low angle grain boundaries and subgrain boundaries. The subgrain boundary content therein was as high as 31.7%, which indicates that this example contains a large amount of lath martensitic structure with a fine size.
Novel 28MnB5 was tested on an Instron-8801 tensile testerThe M bars were subjected to room temperature tensile tests using standard "dog bone" samples cut from the bar core in the length direction at a gauge length of 25mm, the surface and cross section of the tensile samples were polished to remove scale and cut marks prior to testing, the strain values of the samples during stretching were measured by an electronic extensometer during testing, and the strain rate was 1X 10 -3 s -1 . Fig. 10 shows the stress-strain curve of the novel 28MnB5-M grid of this example during stretching. It can be seen that the yield strength of the novel 28MnB5-M grid is 1407MPa and the tensile strength is 1691MPa. This shows that the novel 28MnB5-M grid achieves high yield strength and high tensile strength.
The impact room temperature test was performed on the novel 28MnB5-M grid using an NI300 impact tester, using a standard Charpy V-notch specimen cut from the grid core in the length direction, with a specification of 55X 10mm. Fig. 10 shows the impact test results of the novel 28MnB5-M grid of this example. It can be seen that the impact absorption power of the novel 28MnB5-M grid is 58.0J, and the combination tensile strength data analysis shows that the novel 28MnB5-M grid realizes good toughness matching.
Under the room temperature condition, the novel 28MnB5-M grid bar is tested by adopting an MFT-R4000 type high-speed reciprocating frictional wear tester, zrO ceramic balls with the size of phi 4mm are selected as friction pairs, the loading force is 20N, the stroke is 10mm, the time is 0.5h, and a high-precision balance (the precision is ten thousandth) is used for weighing the weight loss of a sample after the frictional wear test is finished as the wear amount. Fig. 10 shows the abrasion loss test results of the novel 28MnB5-M grid material of this example. It can be seen that the abrasion loss of the novel 28MnB5-M grid material is 1.2mg.
Through the above tests and characterization, the novel 28MnB5-M grid part of the present embodiment can be found to have good toughness matching performance. In addition, the novel 28MnB5-M grid bar after the curved surface design parameters are optimized also has the characteristic of low resistance, and is expected to be applied to the fields of agricultural machinery, advanced industry and the like.
The mechanical performance parameter pairs of the novel 28MnB5-M grid and the existing grid of the embodiment are shown in FIG. 11. As can be seen from fig. 11, the novel 28MnB5-M grid of this example was significantly higher in yield strength (fig. 11 a), tensile strength (fig. 11 b) and toughness (fig. 11 c) than the conventional grid, and the running resistance (fig. 11 d) during operation was also reduced.
Example 3:
the operation steps comprise:
(1) The design and manufacture of the grid comprises:
step 1: and optimizing the grid curved surface by using a horizontal straight element line design method. In order to improve the soil turning capacity of the plow body, reduce the friction between the grid bars and soil and reduce the loss of the plow body, key parameters of the curved surface of the grid bars of the turnover plow are calculated according to the embodiment of 13-15. Wherein the width b of the plow body is 700mm; the value of the plow shovel installation angle epsilon is 30 DEG, and the guide curve upturned angle delta is formed ε Take the value of 11 degrees, C 1 The value is 1.8 as a constant. The value of the opening l of the guide curve is 458mm, the value of the height h of the guide curve is 870mm, and the value of the included angle omega of the tangent line of the end point is 109 degrees.
l＝C 1 b(cosΔε-sinε) (13)
Step 2: and establishing a plow body three-dimensional model by utilizing UG software. Firstly, selecting reference planes to respectively draw a share blade line and a curve sketch; then, drawing a horizontal straight element line by combining the element line number in the element line number formula 16 and the element line angle calculation formula corresponding to the element line number in the element line number formula 16; and finally, drawing a front view of the curved surface of the plow body, and projecting the front view of the curved surface of the plow body to obtain a closed space curve. On the basis, the curved surface of the plow body is cut out by utilizing a cutting command, and then the curved surface of the plow body is changed into a three-dimensional solid shape by utilizing a stretching command, and a stl model file is exported.
Wherein:
n is the element wire number; θ is the angle of the element line; θ m And theta n The element line angles when the element line numbers are m and n are respectively; θ 0 For the initial line angle, 36-45 degrees are generally adopted; θ max And theta min Respectively maximum and minimum element line angles; delta z Is the distance between the element lines;
step 3: ANSYS simulation pre-preparation. Setting soil material attribute parameters: the soil density is 1.78X103 kg/m 3 The elastic modulus is 4.5×107Pa, the Poisson ratio is 0.35, the yield stress is 8.5×105Pa, the tangent modulus is 1.2×106Pa, the failure strain is 0.8, and the strain rate is 6%; setting the characteristic parameters of the turnover plow grid material: the density is 7.81 multiplied by 10 < -6 > kg/mm 3 Elastic modulus is 2.4X105N/mm 2 Poisson's ratio is 0.4; the contact mode between the curved surface of the plow body and the upturned soil is set as automatic contact of face erosion.
Step 4: simulation is performed. Importing the stl model file in the step 2 into the ANSYS simulation environment built in the step 3, and setting the running speed of the plow body part to be 0.38m/s, wherein the advancing direction is the positive direction of the X axis; entering simulation setting, wherein the set time step and the simulation time are 10s; and (3) starting simulation, and obtaining the average resistance value of the plow body part to be 4.90kN after the simulation is completed.
Step 5: preparing novel 28MnB5-M steel. Based on the component design of the existing 28MnB5 steel, adding 0.11 percent of Nb, 0.10 percent of Al and 0.2 percent of Cu (see Table 4 for details), smelting alloy by adopting a vacuum induction furnace, casting into 200kg of cast ingot, and forging into a hot rolled blank of 500mm multiplied by 1000mm multiplied by 50 mm; heating the blank to 1200 ℃, preserving heat for 2.0h, discharging, and performing 3-pass rolling, wherein the final rolling temperature is 920 ℃, and the plate thickness after rolling is 12mm; and (3) cooling the finally rolled plate to the set coiling temperature of 600 ℃ by water, then placing the plate into a heating furnace for heat preservation for 30min, and cooling along with the furnace. Finally, pickling to remove the oxide scale on the surface of the hot rolled plate.
Table 4 chemical composition comparison (mass fraction,%)
Step 6: and (5) machining the grid blank. Cutting the 28MnB5-M hot rolled plate in the step 5 into grid blanks by using an oxygen-acetylene cutting method; and (3) carrying out finish machining on the shape of the grid bar by using a milling machine, and machining countersunk square holes of the grid bar by using a drilling machine.
Step 7: hot forming, normalizing, quenching and tempering the grid bars. Heating the grid blank in the step 6 to 960 ℃, and preserving heat for 1.2h; transferring the grid blank into a stamping die after heat preservation is finished, forming the grid blank into the three-dimensional solid shape required in the step 2, and cooling the grid blank to room temperature in air after forming is finished; heating the grid blank to 920 ℃, preserving heat for 0.7h, immersing in water, and quenching to room temperature; further transferring the quenched grid blank into a tempering furnace with the temperature of 200 ℃ for heat preservation for 2.4 hours, and discharging the quenched grid blank from the furnace for air cooling after heat preservation is finished. Then shot blasting and plastic spraying treatment are carried out to obtain the high-speed turnover plow grid bar component with low running resistance, high strength, high toughness and high wear resistance.
(2) Alloy detection
The novel 28MnB5-M grid microstructure is observed by using a FEI Nova Nano 450 field emission scanning electron microscope and an optical microscope, and samples are sequentially subjected to mosaic, grinding and polishing before the test. FIG. 12 is a scanning electron microscope photograph of the novel 28MnB5-M grid of this example. It can be seen that the structure of the 28MnB5-M grid consists mainly of lath martensite of small size and uniformly distributed, with an average length of about 4.5 μm.
The phase composition of the novel 28MnB5-M grid material is analyzed by adopting an X-ray diffraction (XRD), the X-ray diffraction is tested by using a Japan-Smartlab XRD instrument, a Co target is selected as a target, the scanning speed is 4 degrees/min, and the scanning angle is 30 degrees-110 degrees. Fig. 13 shows the phase composition of the novel 28MnB5-M grid material of this example. It can be seen that the novel 28MnB5-M grid material consists mainly of the alpha phase.
After mechanical grinding and polishing of the 28MnB5-M grid sample, electropolishing was performed at room temperature using an electropolishing solution with a ratio of perchloric acid: alcohol=1:9 (volume ratio), and martensitic orientation imaging analysis was performed on a Gemini SEM 300-type field emission scanning electron microscope equipped with an Oxford-EBSD imaging system, with a scanning step size of 0.06 μm. FIG. 14 shows the EBSD test results of the 28MnB5-M grid sample, and it can be seen that the interface between the martensite blocks consists essentially of high angle grain boundaries, and the internal structure interface of the Martensitic blocks consists essentially of low angle grain boundaries and subgrain boundaries. The subgrain boundary content therein was as high as 37.0%, which indicates that this example contains a large amount of lath martensitic structure with a fine size.
The novel 28MnB5-M grid bar was subjected to room temperature tensile testing on an Instron-8801 tensile testing machine, wherein the tensile sample is a standard 'dog bone shaped' sample cut from the core of the grid bar along the length direction, the gauge length is 25mm, the surface and the section of the tensile sample are required to be polished before the testing to remove oxide scales and cutting marks, the strain value of the sample in the tensile process is measured by an electronic extensometer during the testing, and the strain rate is 1 multiplied by 10 -3 s -1 . Fig. 15 shows the stress-strain curve of the novel 28MnB5-M grid of this example during stretching. It can be seen that the yield strength of the novel 28MnB5-M grid is 1317MPa and the tensile strength is 1632MPa. This shows that the novel 28MnB5-M grid achieves high yield strength and high tensile strength.
The impact room temperature test was performed on the novel 28MnB5-M grid using an NI300 impact tester, using a standard Charpy V-notch specimen cut from the grid core in the length direction, with a specification of 55X 10mm. Fig. 15 shows the impact test results of the novel 28MnB5-M grid of this example. It can be seen that the impact absorption power of the novel 28MnB5-M grid is 57.0J, and the combination tensile strength data analysis shows that the novel 28MnB5-M grid realizes good toughness matching.
Under the room temperature condition, the novel 28MnB5-M grid bar is tested by adopting an MFT-R4000 type high-speed reciprocating frictional wear tester, zrO ceramic balls with the size of phi 4mm are selected as friction pairs, the loading force is 20N, the stroke is 10mm, the time is 0.5h, and a high-precision balance (the precision is ten thousandth) is used for weighing the weight loss of a sample after the frictional wear test is finished as the wear amount. Fig. 15 shows the abrasion loss test result of the novel 28MnB5-M grid material of this example. It can be seen that the abrasion loss of the novel 28MnB5-M grid material is 1.6mg.
Through the above tests and characterization, the novel 28MnB5-M grid part of the present embodiment can be found to have good toughness matching performance. In addition, the novel 28MnB5-M grid bar after the curved surface design parameters are optimized also has the characteristic of low resistance, and is expected to be applied to the fields of agricultural machinery, advanced industry and the like.
The mechanical performance parameter pairs of the novel 28MnB5-M grid and the existing grid of the embodiment are shown in FIG. 16. As can be seen from fig. 16, the novel 28MnB5-M grid of this example was significantly higher in yield strength (fig. 16 a), tensile strength (fig. 16 b) and toughness (fig. 16 c) than the conventional grid, and the running resistance (fig. 16 d) during operation was also reduced.
Claims (4)
1. The modeling method of the high-speed turnover plow grid bar capable of improving mechanical property and reducing resistance is characterized by comprising the following steps of:
step A): optimizing the grid curved surface by using a horizontal straight element line design method, wherein the method comprises the step of obtaining key parameters of the turnover plow grid curved surface according to the following formulas (1) - (3):
l＝C 1 b(cosΔε-sinε) (1)，
wherein:
the width b of the plow body is 640 mm-700 mm,
the value range of the plow shovel installation angle epsilon is 20-30 degrees,
guide curve upturned angle delta ε The value is between 5 degrees and 11 degrees,
C 1 is constant and takes the value between 1.0 and 1.8,
the value range of the opening l of the guide curve determined by the formulas (1) - (3) is 308-458 mm, the value range of the height h of the guide curve is 550-870 mm, and the value range of the included angle omega of the tangent line of the end point is 105-109 degrees;
Step B): establishing a plow body three-dimensional model by utilizing UG software, comprising:
b1 Selecting reference planes and respectively drawing a share blade line and a curve sketch;
b2 Combining the grid curved surface parameters in the step A, and drawing a horizontal straight element line according to the element line number in the formula (4) and an element line angle calculation formula corresponding to the element line number;
b3 Drawing a front view of the curved surface of the plow body, and projecting the front view of the curved surface of the plow body to obtain a closed space curve;
b4 Cutting out the curved surface of the plow body by using a cutting command, changing the curved surface of the plow body into a three-dimensional solid shape by using a stretching command, and exporting a stl model file;
wherein:
n is the element wire number; θ is the angle of the element line; θ m And theta n The element line angles when the element line numbers are m and n are respectively; θ 0 For the initial line angle, 36-45 degrees are generally adopted; θ max And theta min Respectively maximum and minimum element line angles; delta z Is the distance between the element lines;
step C): performing ANSYS simulation pre-preparation, including:
setting soil material attribute parameters: the soil density is 1.76-1.78X103 kg/m 3 The elastic modulus is 4.3-4.5X107 Pa, the Poisson ratio is 0.33-0.35, the yield stress is 8.3-8.5X105 Pa, the tangential modulus is 1.0-1.2X106 Pa, the failure strain is 0.6-0.8, and the strain rate is 4% -6%;
Setting the characteristic parameters of the turnover plow grid material: the density is 7.79-7.81 multiplied by 10 < -6 > kg/mm 3 Modulus of elasticityIs 2.2 to 2.4X105N/mm 2 The Poisson ratio is 0.2-0.4;
setting the contact mode between the curved surface of the plow body and the upturned soil to be automatic contact of surface erosion, and the step D): performing an analog simulation, including:
b, importing the stl model file in the step B into an ANSYS simulation environment built in the step C, and setting the running speed of the plow body part to be 0.36-0.38 m/s, wherein the advancing direction is the positive direction of the X axis;
entering simulation setting, wherein the set time step and the simulation time are 10s in total;
and (5) starting simulation, and obtaining the average resistance value of the plow body component after the simulation is completed.
2. A manufacturing method of a high-speed turnover plow grid bar capable of improving mechanical property and reducing resistance is characterized by comprising the following steps:
step E): preparing a novel 28MnB5-M steel, comprising:
step E1): adding 0.05-0.11% of Nb and 0.04-0.10% of Al element according to the mass fraction shown in table 1 to form 28MnB5-M steel, smelting alloy by adopting a vacuum induction furnace, casting into 200kg cast ingot, and forging into a hot rolled blank with the thickness of 500mm multiplied by 1000mm multiplied by 50 mm; the units in table 1 are mass fraction,
table 1:28MnB5-M steel composition
Step E2): heating the hot rolled blank to 1100-1200 ℃, preserving heat for 1.8-2.0 h, discharging, and performing 3-pass rolling, wherein the finishing temperature is 880-920 ℃, and the plate thickness after rolling is 12mm;
step E3): water-cooling the hot rolled plate after finish rolling to a set coiling temperature of 500-600 ℃, then placing the hot rolled plate into a heating furnace for heat preservation for 28-30 min, and then cooling along with the furnace;
step F): performing a grid blank machining process comprising:
step F1): cutting the 28MnB5-M hot rolled plate in the step E3 into grid blanks by using an oxygen-acetylene cutting method;
step F2): the profile of the grid blank is finished by a milling machine,
step F3): machining a countersunk square hole of the grid blank by using a drilling machine,
step G): performing hot forming, normalizing, quenching and tempering treatment on the grid bars, wherein the hot forming, normalizing, quenching and tempering treatment comprises the following steps of:
step G1): heating the grid blank to 940-960 ℃, and preserving heat for 1.0-1.2 h;
step G2): transferring the grid blank into a stamping die to form the three-dimensional entity required in the step B according to claim 1 after heat preservation, and cooling to room temperature in air after the forming;
step G3): heating the grid blank to 900-920 ℃ again, preserving heat for 0.5-0.7 h, immersing in water, and quenching to room temperature;
step G4): further transferring the quenched grid blank into a tempering furnace with the temperature of 180-200 ℃ for heat preservation for 2.0-2.4 h, and discharging and air cooling after heat preservation is finished.
3. The method of manufacturing a high speed turn plow grid bar of claim 2, further comprising, after step E3:
step E4): pickling to remove the oxide scale on the surface of the hot rolled plate.
4. The method of manufacturing a high speed turn plow grid bar of claim 2, further comprising, after step G4:
step G5): and (3) performing shot blasting and plastic spraying treatment to obtain the high-speed turnover plow grid bar component with low running resistance, high strength, high toughness and high wear resistance.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117668496A (en) * | 2024-01-31 | 2024-03-08 | 泰安市瑞亨建材有限公司 | Geogrid strain testing method and system |
| CN117668496B (en) * | 2024-01-31 | 2024-04-30 | 泰安市瑞亨建材有限公司 | Geogrid strain testing method and system |
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