CN115582678B - Manufacturing method of heavy universal joint cross shaft - Google Patents
Manufacturing method of heavy universal joint cross shaft Download PDFInfo
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- CN115582678B CN115582678B CN202211471884.XA CN202211471884A CN115582678B CN 115582678 B CN115582678 B CN 115582678B CN 202211471884 A CN202211471884 A CN 202211471884A CN 115582678 B CN115582678 B CN 115582678B
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Abstract
The invention discloses a manufacturing method of a heavy universal joint cross shaft, which adopts a brand new processing scheme aiming at the heavy universal joint cross shaft, improves the product quality by utilizing twice annealing, and gradually improves the surface precision of the heavy universal joint cross shaft by utilizing normalizing, heat treatment and milligram energy composite energy treatment. The application also discloses above-mentioned transfer mechanism that carries out station conversion to product, including the anchor clamps body, the anchor clamps body holds the opening including adding, be provided with characteristic lazytongs in the centre gripping opening, characteristic lazytongs keep to be less than 50 ℃ with the alloy material temperature difference. The characteristic synchronization mechanism has hardness smaller than that of the alloy material. The transfer mechanism is synchronous with the workpiece (at the stage) in temperature and hardness by adopting a characteristic synchronization mechanism, so that the surface of the workpiece is prevented from microscopic change or being collided and scratched due to local temperature change.
Description
Technical Field
The invention relates to the technical field of universal joint cross shaft manufacturing, in particular to a manufacturing method of a heavy universal joint cross shaft.
Background
In the manufacturing industry of universal joints, a cross shaft is an extremely important part bearing static torsion strength, but the hot forging method is adopted for the adding process of a cross shaft blank at home and abroad, because the hot forging process is a rough type, a forging blank is rough, the material utilization rate is low, in recent years, cold extrusion is adopted to replace hot forging for products with small specification weight of below 1,5kg, but cold extrusion cannot be carried out for products with large specification weight of 1,5-8kg, and the following problems are mainly (1) that the extrusion force of equipment is particularly large, (2) the extrusion force of a large mold is difficult to manufacture, and (3) cracks are generated at a parting line of the extruded product in the process of cooling, so that the product is scrapped and cannot be produced.
For example, patent publication No. CN108284304B, a cold extrusion process for universal joint cross shaft blank, includes the steps of 1) shearing raw materials into material sections, grinding the surface through centerless grinding, spraying qualified material sections, and drying lubricant; 2) First annealing heat treatment: heating the material section to 850 +/-5 ℃, preserving the heat for 10 hours, cooling to 340 ℃ and 10 ℃, and cooling to room temperature; 3) Performing shot blasting treatment on the material section, and then performing phosphating and saponification treatment; 4) Placing the material section on a hydraulic press for cold extrusion to obtain a cross round bar-shaped blank in a die; 5) Using a low-carbon steel bar hammer to grind circular burrs of the cross round bar-shaped blank to form an outward convex bulge; 6) And (4) polishing the convex bulges on the surface of the cross round rod-shaped blank by using sand paper.
Although the scheme avoids sharp edges caused by cutting by using a cutter, the problem that internal materials which are not chemically treated are exposed on the surface is also avoided, and the defects of visible cracks, scabs, folding and sharp edges after the surface of the existing blank is machined are overcome to a certain extent, the method cannot be applied to the machining scheme of the heavy cross shaft which is formed by high extrusion force, and the problems of size deformation, surface cracks and the like caused by high residual stress after extrusion forming cannot be avoided. In order to solve the problems, the blank precision of a product is improved, few cutting is realized, and economic benefits are improved, the application provides a manufacturing method of a heavy universal joint cross shaft and a transfer mechanism for transferring the heavy universal joint cross shaft between machining steps.
Disclosure of Invention
Aiming at the problems of low precision and high production cost of a heavy universal joint cross shaft blank in the prior art mentioned in the background technology, the invention provides a brand new processing scheme aiming at the heavy universal joint cross shaft, improves the product quality by utilizing twice annealing, and gradually improves the surface precision of the heavy universal joint cross shaft by utilizing normalizing, heat treatment and milligram energy composite energy treatment.
The second object of the present invention is: the problem of when adopting cold extrusion technology to make and appear the fracture easily and lead to the product to be scrapped is solved, accurate control temperature in the stress relief annealing process after the shaping, the residual stress after effectively reducing heavy universal joint cross cold extrusion shaping, avoids heavy universal joint cross to lead to size precision to descend or even product fracture because of the high stress problem.
The third object of the present invention: the method solves the problems that local severe temperature changes are easy to occur in the conversion process of each processing step of the product, the surface treatment effect of the product is influenced, and the residual stress is increased to reduce the stress removing effect.
In order to achieve the purpose, the invention adopts the following technical scheme:
a manufacturing method of a heavy universal joint cross shaft comprises the following steps:
s1, cutting an alloy material to be processed into bars according to the required specification and size, and blanking;
s2, transferring the cut bar stock in the S1 by using a transfer clamp and carrying out spheroidizing annealing to ensure that the spheroidization rate of the metallographic structure is more than 90%;
s3, performing shot blasting treatment on the annealed bar stock in the S2, and removing the surface of surface oxide skin; uniformly brushing a lubricant;
s4, coating a lubricant on the bar subjected to shot blasting in the S3;
s5, placing the bar coated with the lubricant in the step S4 in a cold extrusion die for extrusion forming;
s6, placing the product formed in the step S5 in a heat-preservation oven by using a transfer fixture, heating to 550-600 ℃ below Ac1, preserving heat for 3.5-5h, cooling to 200-300 ℃ along with the oven, preserving heat for 2-4h, taking out, cooling to room temperature, and finally transferring to an annealing furnace to finish stress relief annealing;
s7, transferring the product annealed in the step S6 by using a transfer clamp for normalizing, wherein the hardness after normalizing is HB156-207, and the internal structure is equiaxed pearlite plus ferrite;
s8, carrying out shot blasting on the product subjected to normalizing in the step S7, and carrying out turning according to the design size after shot blasting;
s9, performing carburizing and quenching treatment on the product subjected to turning in the S8;
s10, grinding the product subjected to carburizing and quenching treatment in the step S9, wherein the surface roughness of the product after grinding is within Ra0.4;
s11, performing milligram energy composite energy treatment on the product subjected to the grinding processing in the step S10, performing secondary strengthening on the surface of the product by a high-frequency rolling technology, wherein the surface roughness of the rolled product is within Ra0.1, and the surface hardness reaches HRC65-68.
In the method, the heat preservation oven is utilized to immediately preserve heat of the cold extrusion molding, so that the cracking caused by the release of residual stress in the direct cooling process of the product is avoided. Particularly, the blank of the cross shaft after cold extrusion has the residual temperature of 200-300 ℃, so that the energy can be effectively saved by directly heating the temperature to 550-600 ℃ in the heat-insulating oven.
Further, in the spheroidizing annealing process in S1, the hardness of the bar is HRB70 or less, the spheroidization rate is more than 90%, and the metallographic structure is spherical pearlite and ferrite. The hardness of the blank is reduced to be lower than HRB75 through spheroidizing annealing, the plasticity and the fluidity of the blank are improved, the cold extrusion forming is facilitated, and the spheroidization rate of a metallographic structure reaches over 90 percent.
Preferably, the surface hardness of the product after carburization and quenching treatment in the S9 is HRC62-65, the core hardness is HRC28-45, and the surface martensite structure is; 2-4 grade, and the core is laminated low-carbon martensite plus ferrite. The core is subjected to carburizing and quenching treatment to obtain a laminated structure, so that the static torsion strength of the product is improved by more than 15% compared with that of hot forging, and better mechanical properties are obtained.
Preferably, in the S11 milligram energy composite energy treatment process, a double-point type pressure head is adopted to impact the surface of the product for 3 ten thousand times per second, a super wear-resistant layer is formed on the surface of the treated product, the surface roughness of the super wear-resistant layer is within Ra0.1, and the surface hardness is HRC65-68. By installing millienergy on a numerical control lathe and adopting a rolling technology of high-frequency impact of a double-point pressure head for 3 ten thousand times per second, the metal surface is secondarily strengthened, the surface of a shaft neck after rolling reaches a mirror surface, the roughness is within Ra0.1, the surface hardness is improved by more than HRC3 degrees from the carburization quenching basis to reach HRC65-68, and the industrial standard requirement is exceeded; the hardness of the super wear-resistant layer formed on the surface of the shaft neck is obviously improved, so that the wear life of the universal joint cross shaft is prolonged by more than one year.
Further, the grinding processing in the step S10 is divided into two steps, in the first step, two end faces of the product are finely ground on a double-end-face grinding machine so that the tolerance of the two end faces is within 0.02, and the roughness is within Ra0.4; and secondly, finely grinding four-shaft necks of products on a centerless grinder for the cross shaft, automatically finishing to enable the necks to be in smooth transition connection with fillets, and controlling the dimensional tolerance of the necks to be within 0.01 and the surface roughness Ra0.4 after grinding.
The application also discloses above-mentioned transfer mechanism that carries out station conversion to the product, including the anchor clamps body, the anchor clamps body is including the centre gripping opening, be provided with characteristic lazytongs in the centre gripping opening, characteristic lazytongs keeps being less than 50 ℃ with the alloy material temperature difference. The characteristic synchronization mechanism is less hard than the alloy material.
The clamp body is used for carrying out position transfer on a workpiece in each processing stage, the characteristic synchronization mechanism is a direct joint of the clamp body and the workpiece, the temperature of the product is frequently changed in the steps of annealing, normalizing, heat treatment and the like, the surface hardness is lower before the product is cooled, the requirement on the surface roughness of the heavy universal joint cross shaft is extremely high, and mirror-image-level roughness is required after the heavy universal joint is processed, so when the heavy universal joint is subjected to position conversion in each step in the processing process, if a traditional lifting appliance is adopted for displacement, the problem of collision is avoided, when a mechanical claw is adopted for grabbing, when the temperature difference of a contact position is too large, the local surface temperature is suddenly changed to influence the surface quality of an incomplete full-plastic type, and the characteristic synchronization mechanism is used for carrying out position transfer on the product among the processing steps, so that the problems that the local surface temperature suddenly changes to change the microstructure of the product or the surface of the workpiece is frequently clamped and scratched are solved, and the third invention of the application is avoided.
Preferably, the characteristic synchronization mechanism comprises a temperature-resistant part which is detachably arranged on the inner wall of the clamping opening; the edge of the temperature-resistant part is provided with a heat-insulating side wall, the heat-resistant part is covered with a heat-insulating main board, and the edge of the heat-insulating main board is connected with the heat-insulating side wall in a sliding insertion manner. Specifically, the temperature-resistant part is made of a material with a melting point higher than the processing environment of the product, is inserted in the clamping opening in an interference manner and is used as a part of the clamping opening, which is in contact with the product; the heat preservation lateral wall sets up with temperature resistant portion parallel and level, and the terminal surface of heat preservation lateral wall is provided with the mounting groove, be provided with the installation sand grip on the heat preservation mainboard, possess residual temperature and when idle at temperature resistant portion, the accessible heated board covers it and keeps warm, reduces energy dissipation for temperature resistant portion and product surface's the difference in temperature can not be too big and lead to local temperature sudden change, promotion energy utilization before next synchronous operation begins. Specifically, when the workpiece enters different temperature environments such as annealing, normalizing and heat preservation in the machining process according to machining procedures, an operator can add the temperature-resistant part into the machining environment together with the workpiece, so that the temperature of the temperature-resistant part and the temperature of the workpiece are kept in a synchronous state, the temperature allowance of +/-50 ℃ is preset in consideration of the difference between the temperature-resistant part and the workpiece in specific heat capacity, which is different from the material of the workpiece and objectively exists, the temperature influence of the temperature-resistant part on the workpiece can be reduced to be ignored within the range, the characteristic synchronization is realized, and the local microscopic denaturation of the surface of the workpiece is effectively reduced.
The application also discloses an alloy material for processing the heavy universal joint cross shaft, and relates to high-strength alloy steel, wherein the high-strength alloy steel comprises the following components in percentage by mass: 0.15-0.25%, si:0.15-0.25%, mn:0.40-0.70%, cr:0.90-1.40%, S is less than or equal to 0.015%, P is less than or equal to 0.025%, ni is less than or equal to 0.03%, mo: not more than 0.15%, not more than 0.20% of Cu, al:0.02 to 0.05%, ti:0.02 to 0.05%, B:0.001 to 0.003% of Fe and inevitable impurities as the balance. 1) Determination of C content
C is a main element second to iron, and directly influences the strength, plasticity and toughness properties of the steel. However, the excessively high C content is unfavorable for the toughness of steel and unfavorable for cold extrusion molding, and the content of the C content is controlled to be 0.15-0.25%.
2) Determination of the Si content
Si is an important reducing agent and deoxidizing agent in the steel-making process, and improves the hardness and strength of steel in a solid solution strengthening mode. However, when the Si content is high, the toughness of the steel is lowered, and the Si increases the susceptibility to overheating, cracking, and decarburization tendency in the steel. The invention controls the content of Si to be 0.15-0.25%.
3) Determination of Mn content
Mn is an element effective for strengthening steel as a deoxidizing element in the steel-making process, and plays a role in solid solution strengthening. And Mn can improve the hardenability of the steel. Mn can form MnS with a high melting point with S in steel smelting, thereby weakening and eliminating the adverse effect of S. However, the high Mn content lowers the toughness of the steel and increases the cold deformation resistance of the steel. The Mn content of the invention is controlled between 0.40 and 0.70 percent.
4) Determination of the Cr content
Cr is a carbide-forming element and can improve the hardenability and wear resistance of steel. The range of the Cr content of the present invention is determined to be 0.90-1.40%.
5) Determination of Al content
Al is added into steel as a deoxidizer or an alloying element, and the aluminum deoxidation capability is much stronger than that of silicon and manganese. The main functions of aluminum in steel are grain refinement and nitrogen fixation, so that the impact toughness of the steel is remarkably improved, and the cold brittleness tendency and the aging tendency are reduced. The range of the Al content in the present invention is determined to be 0.02-0.05%.
6) Determination of the TI content
Titanium and nitrogen, oxygen and carbon have strong affinity, and the affinity with sulfur is stronger than that of iron, so that the titanium-iron-based oxygen-removing deoxidizing agent is a good deoxidizing and degassing agent and an effective element for fixing nitrogen and carbon. Titanium can improve the plasticity and the toughness in common low alloy steel. The strength of the steel is improved because titanium fixes nitrogen and sulfur and forms titanium carbide. The range of the Ti content of the present invention is determined to be 0.02-0.05%.
7) Determination of the B content
B can improve the hardenability of the steel, can also improve the high-temperature strength of the steel, and can play a role in strengthening grain boundaries in the steel, and the content range of the B is determined to be 0.001-0.003%.
8) Determination of the N content
When supersaturated nitrogen is dissolved in steel, the nitrogen is precipitated in the form of nitride after being placed for a long period of time, and the hardness and strength of the steel are improved, the plasticity is reduced, and the aging is performed. The proper amount of aluminum is added into the steel, stable AlN can be generated, the generation and precipitation of Fe4N can be suppressed, the timeliness of the steel is improved, the growth of austenite grains can be prevented, and the effect of refining the grains is achieved. But nitrogen will form nitride non-metallic inclusions with alloying elements in the steel and more importantly reduce the effect of the alloying elements. When the nitrogen content in the steel is high, the strength of the steel is increased, and the impact toughness is reduced. The N content of the present invention is determined to be 0.005-0.014%.
9) Determination of the O content
The oxygen content represents the total amount of oxide inclusions, the limitation of the oxide brittle inclusions influences the service life of a finished product, and a large number of tests show that the reduction of the oxygen content is obviously beneficial to improving the purity of steel, particularly reducing the content of the oxide brittle inclusions in steel. The oxygen content of the invention is determined to be less than or equal to 0.0010 percent.
10 Determination of P, S content
P is highly segregated in steel during solidification, and P dissolves in ferrite to distort and coarsen crystal grains and increase cold shortness. The range of the P content of the invention is determined to be less than or equal to 0.025 percent. S causes the steel to generate hot brittleness, reduces the ductility and the toughness of the steel, but can improve the cutting performance of the steel, and the range of the S content is determined to be less than or equal to 0.015 percent.
Therefore, the invention has the following beneficial effects: (1) The method adopts a brand new processing scheme aiming at the heavy universal joint cross shaft, improves the product quality by utilizing twice annealing, and gradually improves the surface precision of the universal joint cross shaft by utilizing normalizing, heat treatment and milligram energy composite energy treatment; (2) The core is subjected to carburizing and quenching treatment to obtain a laminated structure, so that the static torsion strength of the product is improved by more than 15% compared with that of hot forging, and better mechanical properties are obtained; (3) The transfer mechanism is synchronous with the workpiece (at this stage) in temperature and hardness by adopting a characteristic synchronization mechanism, so that the surface of the workpiece is prevented from being microscopically changed or scratched due to collision caused by local temperature change; (4) The milligram energy composite energy is utilized to process the heavy universal joint cross shaft, so that the hardness of a super wear-resistant layer formed on the surface of a shaft neck is obviously improved, and the wear life of the universal joint cross shaft is prolonged by more than one time; (5) The heavy universal joint cross shaft is processed by adopting high-strength alloy steel with special components as a raw material, so that the strength, hardness and toughness of the heavy universal joint cross shaft are obviously improved, and the heavy universal joint cross shaft has high purity.
Drawings
FIG. 1 is a process curve of the spheroidizing annealing process of example 1;
FIG. 2 is a process curve of the stress relief annealing process in example 1;
FIG. 3 is a process curve of the carburizing and quenching process in example 1;
FIG. 4 is a process curve of the normalizing process in example 1;
fig. 5 is a schematic structural view of the transfer mechanism disclosed in embodiment 2;
fig. 6 is a partially enlarged view of a point a in fig. 5.
1. The fixture comprises a fixture body, 2, a clamping opening, 3, a temperature-resistant part, 4, a heat-insulating side wall, 5 and a mounting groove.
Detailed Description
Example 1
A manufacturing method of a heavy universal joint cross shaft comprises the following steps of S1, cutting an alloy material to be processed into bars according to required specification and size, and blanking;
s2, transferring the cut bar stock in the S1 by using a transfer clamp and carrying out spheroidizing annealing to ensure that the spheroidization rate of a metallographic structure is more than 90%;
s3, performing shot blasting treatment on the bar stock annealed in the S2, and removing the surface of the surface oxide skin; uniformly brushing a lubricant;
s4, coating a lubricant on the bar subjected to shot blasting in the S3;
s5, placing the bar coated with the lubricant in the step S4 in a cold extrusion die for extrusion forming;
s6, placing the product formed in the S5 in an insulation oven by using a transfer fixture, heating to 550-600 ℃ below Ac1, insulating for 3.5-5h, cooling to 200-300 ℃ along with the oven, insulating for 2-4h, taking out, cooling to room temperature, and finally transferring to an annealing furnace to finish stress relief annealing;
s7, transferring the product annealed in the step S6 by using a transfer fixture for normalizing, wherein the hardness after normalizing is HB156-207, and the internal structure is equiaxed pearlite plus ferrite;
s8, carrying out shot blasting on the product subjected to normalizing in the step S7, and carrying out turning according to the design size after shot blasting;
s9, performing carburizing and quenching treatment on the product subjected to turning in the S8;
s10, grinding the product subjected to carburizing and quenching treatment in the step S9, wherein the surface roughness of the product after grinding is within Ra0.4;
s11, performing milligram energy composite energy treatment on the product subjected to the grinding processing in the step S10, performing secondary strengthening on the surface of the product by a high-frequency rolling technology, wherein the surface roughness of the rolled product is within Ra0.1, and the surface hardness reaches HRC65-68.
In the method, the heat preservation oven is utilized to immediately preserve heat of the cold extrusion molding, so that the cracking caused by the release of residual stress in the direct cooling process of the product is avoided. Particularly, the cold extruded cross shaft blank has residual temperature of 200-300 ℃, so that energy can be effectively saved by directly heating the temperature to 550-600 ℃ in a heat-preservation oven.
As shown in fig. 1-4, the precise cold extrusion manufacturing method of the heavy truck cross shaft comprises the following steps of; designing a special material for the cross shaft; blanking a cross shaft, removing burrs of a fillet at the two ends, spheroidizing annealing, shot blasting, lubricating the surface, carrying out semi-closed cold extrusion molding on a large-scale press die, carrying out heat preservation on a workpiece after discharging, immediately carrying out induced stress annealing, normalizing, shot blasting, turning, carburizing and quenching by a heat treatment machine, carrying out grinding and carrying out milligram energy rolling and super-precision treatment on the workpiece in three minutes; and carrying out the following various process steps;
the six-meter bar stock in the supply state is automatically blanked on an automatic circular sawing machine and cut into material sections with required weight.
Further, the two-end sharp corner of the blank is deburred and is chamfered into a fillet of 2 mm on the double-end automatic chamfering machine, so that the defects of molding, collision damage and the like are avoided.
Further, spheroidizing annealing is carried out in a well type furnace with protective atmosphere; in particular according to the process curve. The hardness is lower than HRB70, the nodularity is more than 90 percent, and the metallographic structure is spherical pearlite and ferrite.
Further, shot blasting is carried out on the blank to remove surface oxide skin.
Further, the blank is subjected to graphite polymer surface treatment on full-automatic control surface lubrication treatment equipment. The method is carried out according to the process steps.
Further, cold extrusion forming is carried out on a 5000-ton press, the workpiece is conveyed into a die cavity for forming by an automatic feeding machine and a robot, the die is released after hydraulic forming of the press, the workpiece is taken out by the robot, conveyed to a 300-DEG heat preservation oven through a conveyor belt for heat preservation, taken out of the heat preservation oven after a basket of the workpiece is full, and lifted into a pit furnace within 3 minutes for stress taking annealing. Effectively preventing the workpiece from cracking caused by stress release in the cooling process. See the stress annealing process for details.
Further, the fully automatic mesh belt furnace is subjected to normalizing treatment, the hardness after the normalizing treatment is HB156-207, the internal structure is equiaxed pearlite and ferrite, and the normalizing process shown in FIG. 4 is detailed. Ensuring the machinability and the lifting value of carburized and quenched tissues to be 2095076.
Further, the workpiece is shot-blasted on a turntable shot-blasting machine to achieve bright surface without black spots, burrs and the like
Further, the blank is positioned on a numerically controlled automatic lathe through an automatic rotary turning clamp to complete the turning process of the four shaft necks, and meanwhile, the processing process of the blind holes is completed at one time. Within the dimensional tolerance of 0.05 and within the roughness Ra0.63
Further, carburizing and quenching treatment is carried out on a push rod type automatic carburizing and quenching device, and the detailed description is a heat treatment process. The surface hardness of the workpiece after heat treatment is HRC62-65, the core hardness is HRC28-45, and the surface martensite structure is; grade 2-4, the core part is; laminated low-carbon martensite plus ferrite. Due to the laminated structure, the static torsional strength is improved by more than 15 percent compared with that of flat hot forging.
Further, automatically feeding, clamping and positioning two end surfaces of the mill on a double-end-surface mill, automatically rotating for 180 degrees, and then milling the two end surfaces to achieve the tolerance of the two end surfaces within 0.02 and the roughness; ra0.4 or less.
Furthermore, the four shaft necks are finely ground on a centerless grinding machine special for the full-automatic cross shaft, the shaft necks are automatically trimmed and connected with the R, and a size tolerance control table of the ground shaft necks is within 0.01. The surface roughness is within 0.4 and the circular arc is smoothly connected.
Furthermore, the four shaft diameter surfaces of the cross shaft are subjected to heat treatment, carburizing and quenching, and the wear resistance of the surface of the cross shaft neck is further improved; treating by using milligram energy composite energy; by installing millienergy on a numerical control lathe and adopting a rolling technology of high-frequency impact of a double-point pressure head for 3 ten thousand times per second, the metal surface is secondarily strengthened, the surface of a shaft neck after rolling reaches a mirror surface, the roughness is within Ra0.1, the surface hardness is improved by more than HRC3 degrees from the carburization quenching, the HRC65-68 is reached, and the requirements of the industry standard are exceeded; the surface of the shaft neck is formed with a superhard wear-resistant layer, so that the wear life of the universal joint cross shaft can be prolonged by more than one time.
The precision cross shaft of the heavy truck cold extrusion is manufactured by the manufacturing method of the technology of stress annealing, heat treatment carburizing and quenching, grinding and milligram energy processing immediately after the precision cold extrusion and the special quick heat preservation of the cross shaft, and is applicable to various heavy trucks, military vehicle transmission shafts, transmission shafts of engineering machinery, ships and the like; the universal joint cross has the advantages of wide application range and good process stability and strength, solves the process bottleneck of cold extrusion of large-size cross shafts at home and abroad, and can effectively control the cracking problem in the cold extrusion process, so that the wear life of the universal joint cross shaft is prolonged by more than one time.
Example 2
As shown in fig. 5 and 6, the embodiment discloses a transfer mechanism for station conversion in product processing, which comprises a fixture body, wherein the fixture body comprises a clamping opening, a characteristic synchronization mechanism is arranged in the clamping opening, and the characteristic synchronization mechanism keeps a temperature difference with an alloy material less than 50 ℃. The characteristic synchronization mechanism has hardness smaller than that of the alloy material. The characteristic synchronization mechanism comprises a temperature-resistant part inserted and arranged on the inner wall of the clamping opening; the temperature resistant part border is provided with heat preservation lateral wall, the temperature resistant part upper cover is provided with the heat preservation mainboard, the border of heat preservation mainboard slides to insert to close connects the heat preservation lateral wall. The temperature resistant part in this embodiment adopts graphite to make, and hardness and melting point accord with the demand, and can not produce the reaction with the product surface.
The fixture body is used for carrying out position transfer on workpieces in various machining stages, the characteristic synchronization mechanism is a direct joint of the fixture body and the workpieces, the temperature of the products in the steps of annealing, normalizing, heat treatment and the like is frequently changed, the surface hardness is lower before the products are not cooled, the requirement on the surface roughness of the heavy universal joint cross shaft is extremely high, and mirror-image-level roughness is required after machining is finished, so when the heavy universal joint is subjected to position conversion in various steps in the machining process, if a traditional lifting appliance is adopted for displacement, the problem of collision is avoided, when a mechanical claw is adopted for grabbing, when the temperature difference of a contact position is too large, the local surface temperature is suddenly changed to influence the surface quality of an incomplete full-plastic type, and the characteristic synchronization mechanism is used for carrying out position transfer on the products among various machining steps, so that the problems that the local surface temperature suddenly changes to change the microstructure of the products or the surfaces of the workpieces are frequently clamped and scratched are solved, and therefore, the characteristic synchronization mechanism is adopted to be synchronized with the workpieces (in the temperature and hardness.
Specifically, the temperature-resistant part is made of a material with a melting point higher than the processing environment of the product, and the temperature-resistant part is inserted into or is fixed on all surfaces of the clamping opening, which are in contact with the product, in a pressing manner; the heat preservation lateral wall sets up with temperature resistant portion parallel and level, and the terminal surface of heat preservation lateral wall is provided with the mounting groove, be provided with the installation sand grip on the heat preservation mainboard, possess residual temperature and when idle at temperature resistant portion, the accessible heated board covers it and keeps warm, reduces energy dissipation for temperature resistant portion and product surface's the difference in temperature can not be too big and lead to local temperature sudden change, promotion energy utilization before next synchronous operation begins.
Example 3
The embodiment discloses an alloy material for processing a heavy universal joint cross shaft, and relates to high-strength alloy steel, wherein the high-strength alloy steel comprises the following components in percentage by mass: 0.15-0.25%, si:0.15-0.25%, mn:0.40-0.70%, cr:0.90-1.40%, S is less than or equal to 0.015%, P is less than or equal to 0.025%, ni is less than or equal to 0.03%, mo: less than or equal to 0.15 percent, less than or equal to 0.20 percent of Cu, al:0.02-0.05%, ti:0.02 to 0.05%, B: 0.001-0.003% of Fe and inevitable impurities as the rest.
1) Determination of C content
C is a main element second to iron, and directly influences the strength, plasticity and toughness properties of the steel. However, the excessively high C content is unfavorable for the toughness of steel and unfavorable for cold extrusion molding, and the content of the C content is controlled to be 0.15-0.25%.
2) Determination of the Si content
Si is an important reducing agent and deoxidizing agent in the steel-making process, and improves the hardness and strength of steel in a solid solution strengthening mode. However, when the Si content is high, the toughness of the steel is lowered, and the Si increases the susceptibility to overheating, cracking, and decarburization tendency in the steel. The invention controls the content of Si to be 0.15-0.25%.
3) Determination of Mn content
Mn is an element effective for strengthening steel as a deoxidizing element in the steel-making process, and plays a role in solid solution strengthening. And Mn can improve the hardenability of steel. Mn can form MnS with a high melting point with S in steel smelting, thereby weakening and eliminating the adverse effect of S. However, the high Mn content reduces the toughness of the steel and increases the cold deformation resistance of the steel. The Mn content of the invention is controlled to be 0.40-0.70%.
4) Determination of the Cr content
Cr is a carbide-forming element and can improve the hardenability and wear resistance of steel. The range of the Cr content of the present invention is determined to be 0.90-1.40%.
5) Determination of Al content
Al is added into steel as a deoxidizer or an alloying element, and the aluminum deoxidation capability is much stronger than that of silicon and manganese. The main functions of aluminum in steel are to refine crystal grains and fix nitrogen in the steel, so that the impact toughness of the steel is obviously improved, and the cold brittleness tendency and the aging tendency are reduced. The Al content of the present invention is determined to be in the range of 0.02 to 0.05%.
6) Determination of TI content
Titanium and nitrogen, oxygen and carbon have strong affinity, and the affinity with sulfur is stronger than that of iron, so that the titanium-iron-based oxygen-removing deoxidizing agent is a good deoxidizing and degassing agent and an effective element for fixing nitrogen and carbon. Titanium can improve the plasticity and the toughness in the common low alloy steel. The strength of the steel is improved because titanium fixes nitrogen and sulfur and forms titanium carbide. The range of the Ti content of the present invention is determined to be 0.02-0.05%.
7) Determination of B content
B can improve the hardenability of steel, can also improve the high-temperature strength of the steel, and can play a role in strengthening grain boundaries in the steel, and the content range of the B is determined to be 0.001-0.003%.
8) Determination of the N content
When supersaturated nitrogen is dissolved in steel, the nitrogen is precipitated in the form of nitride after being placed for a long period of time, and the hardness and strength of the steel are improved, the plasticity is reduced, and the aging is carried out. The proper amount of aluminum is added into the steel, stable AlN can be generated, the generation and precipitation of Fe4N can be suppressed, the timeliness of the steel is improved, the growth of austenite grains can be prevented, and the effect of refining the grains is achieved. But nitrogen will form nitride non-metallic inclusions with the alloying elements in the steel and more importantly reduce the effects of the alloying elements. When the nitrogen content in the steel is high, the strength of the steel is increased, and the impact toughness is reduced. The N content of the present invention is determined to be 0.005-0.014%.
9) Determination of the O content
The oxygen content represents the total amount of oxide inclusions, the limitation of the oxide brittle inclusions influences the service life of a finished product, and a large number of tests show that the reduction of the oxygen content is obviously beneficial to improving the purity of steel, particularly reducing the content of the oxide brittle inclusions in steel. The oxygen content of the invention is determined to be less than or equal to 0.0010 percent.
10 Determination of P, S content
P is highly segregated in steel during solidification, and P dissolves in ferrite to distort and coarsen crystal grains and increase cold shortness. The range of the P content of the invention is determined to be less than or equal to 0.025 percent. S causes the steel to generate hot brittleness, reduces the ductility and the toughness of the steel, but can improve the cutting performance of the steel, and the range of the S content is determined to be less than or equal to 0.015 percent.
In this embodiment, the standard requirements and actual test results of the high-strength alloy steel are as follows.
| C | Si | Mn | Cr | Ti | P | S | Ni | Cu | Mo | |
| Standard requirements | 0.18～0.23 | 0.17～0.37 | 0.80～1.10 | 1.00～1.30 | 0.04～0.10 | ≤0.035 | ≤0.035 | ≤0.30 | ≤0.20 | ≤0.06 |
| Actual detection | 0.21 | 0.32 | 1.02 | 1.06 | 0.06 | 0.012 | 0.009 | 0.05 | 0.03 | 0.001 |
In addition to the above embodiments, the technical features of the present invention can be re-selected and combined to form new embodiments within the scope of the claims and the specification of the present invention, which are all realized by those skilled in the art without creative efforts, and thus, the embodiments of the present invention which are not described in detail should be regarded as the specific embodiments of the present invention and are within the protection scope of the present invention.
Claims (9)
1. A manufacturing method of a heavy universal joint cross shaft is characterized by comprising the following steps:
s1, cutting an alloy material to be processed into bars according to required specification and size, and blanking;
s2, transferring the cut bar stock in the S1 by using a transfer mechanism and carrying out spheroidizing annealing to ensure that the spheroidizing rate of a metallographic structure is more than 90%;
s3, performing shot blasting treatment on the annealed bar stock in the S2, and removing the surface of surface oxide skin; uniformly brushing a lubricant;
s4, coating a lubricant on the bar subjected to shot blasting in the S3;
s5, placing the bar coated with the lubricant in the step S4 in a cold extrusion die for extrusion forming;
s6, placing the product formed in the step S5 in a heat-preservation oven by using a transfer mechanism, heating to 550-600 ℃ below Ac1, preserving heat for 3.5-5h, cooling to 200-300 ℃ along with the oven, preserving heat for 2-4h, taking out, cooling to room temperature, and finally transferring to an annealing furnace to finish stress relief annealing;
s7, transferring the product annealed in the step S6 by using a transfer mechanism for normalizing, wherein the hardness after normalizing is HB156-207, and the internal structure is equiaxed pearlite plus ferrite;
s8, carrying out shot blasting on the product subjected to normalizing in the step S7, and carrying out turning according to the design size after shot blasting;
s9, performing carburizing and quenching treatment on the product subjected to turning in the S8;
s10, grinding the product subjected to carburizing and quenching treatment in the S9, wherein the surface roughness of the product after grinding is within Ra0.4;
s11, performing milligram energy composite energy treatment on the product after the grinding processing in the S10, performing secondary strengthening on the surface of the product through a high-frequency rolling technology, and obtaining the surface roughness of the rolled product: the surface hardness is within Ra0.1 and HRC65-68;
the transfer mechanism comprises a clamp body, the clamp body comprises a clamping opening, a characteristic synchronization mechanism is arranged in the clamping opening, and the characteristic synchronization mechanism comprises a temperature-resistant part which is embedded in the inner wall of the clamping opening.
2. The method for manufacturing the heavy universal joint cross according to claim 1, wherein in the S1 spheroidizing annealing process, the hardness of the bar stock is HRB70 or less, the spheroidization rate is more than 90%, and the metallographic structure is spherical pearlite + ferrite.
3. The method for manufacturing the heavy universal joint cross shaft according to claim 1, wherein the surface hardness of the product after the carburizing and quenching treatment in the S9 is HRC62-65, the core hardness is HRC28-45, and the surface martensite structure is; 2-4 grade, and the core is laminated low-carbon martensite + ferrite.
4. The manufacturing method of the heavy universal joint cross shaft according to claim 1, wherein in the S11 milligram energy composite energy treatment process, the surface of the product is impacted by a double-point pressure head 3 ten thousand times per second, a super wear-resistant layer is formed on the surface of the treated product, and the surface roughness of the super wear-resistant layer is as follows: the Ra0.1 or less and the surface hardness is HRC65-68.
5. The method of claim 1, wherein the grinding in S10 is performed in two steps, and in the first step, both end faces of the product are ground on a double-end-face grinding machine to achieve both end face tolerances within 0.02, and the roughness: ra0.4 or less; and secondly, finely grinding the four-shaft neck of the product on a centerless grinder for the cross shaft, automatically finishing to enable the shaft neck to be in smooth transition connection with a fillet, and controlling the dimensional tolerance of the ground shaft neck within 0.01 and the surface roughness within 0.4.
6. The method of claim 1, wherein the characteristic synchronization mechanism maintains a temperature difference of less than 50 ℃ from the alloy material.
7. The manufacturing method of the heavy universal joint cross shaft according to claim 6, wherein a heat preservation side wall is arranged at the edge of the heat-resistant part, a heat preservation main plate is arranged on the heat-resistant part in a covering mode, and the edge of the heat preservation main plate is connected with the heat preservation side wall in a sliding insertion mode.
8. The method of claim 6, wherein the characteristic synchronization mechanism is less hard than the alloy material.
9. The manufacturing method of the heavy universal joint cross according to claim 1, wherein the alloy material to be processed is high-strength alloy steel, and the high-strength alloy steel comprises the following components in percentage by mass: 0.15-0.25%, si:0.15-0.25%, mn:0.40-0.70%, cr:0.90-1.40%, S is less than or equal to 0.015%, P is less than or equal to 0.025%, ni is less than or equal to 0.03%, mo: less than or equal to 0.15 percent, less than or equal to 0.20 percent of Cu, al:0.02 to 0.05%, ti:0.02 to 0.05%, B:0.001 to 0.003 percent, and the balance of Fe and inevitable impurities.
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| ITPN20030043A1 (en) * | 2003-07-21 | 2005-01-22 | Euroform Srl | PROCEDURE FOR MANUFACTURING A COUPLING ORGAN, |
| CN101862944B (en) * | 2010-04-15 | 2012-05-23 | 南通振华重型装备制造有限公司 | Machining process of planet carrier of differential reduction gearbox |
| CN102773676B (en) * | 2012-08-16 | 2015-04-22 | 玉环普天单向器有限公司 | Manufacture method of overrunning coupler directional sleeve and die thereof |
| CN103042358A (en) * | 2012-09-11 | 2013-04-17 | 昌利锻造有限公司 | Method for manufacturing universal joint for automobile |
| CN103111815B (en) * | 2013-02-28 | 2015-05-20 | 重庆路畅汽车配件有限公司 | Secondary synchronous cold extruding forming production method for cross axles of automobile differentials and planetary reducers |
| CN104476146A (en) * | 2014-10-30 | 2015-04-01 | 江苏威鹰机械有限公司 | Production process of automotive middle-rear axle transmission meshing sleeve |
| CN105729078A (en) * | 2014-12-12 | 2016-07-06 | 重庆晨宇机床制造有限公司 | Cross axle cold extruding technology |
| CN108284304B (en) * | 2017-12-27 | 2019-10-01 | 杭州新世纪万向节有限公司 | Universal-joint cross trunnion blank cold-extruded processing technology |
| CN109352288B (en) * | 2018-12-11 | 2020-11-27 | 岑重英 | Cold extrusion pressing forming process for automobile universal joint fork integral piece |
| CN114959442B (en) * | 2022-03-16 | 2023-03-31 | 江阴兴澄特种钢铁有限公司 | Steel for universal joint cross shaft for cold extrusion and manufacturing method thereof |
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