CN111408681B - Method for tempering non-quenched and tempered steel connecting rod of engine by using waste heat after forging - Google Patents
Method for tempering non-quenched and tempered steel connecting rod of engine by using waste heat after forging Download PDFInfo
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- CN111408681B CN111408681B CN202010285561.6A CN202010285561A CN111408681B CN 111408681 B CN111408681 B CN 111408681B CN 202010285561 A CN202010285561 A CN 202010285561A CN 111408681 B CN111408681 B CN 111408681B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K1/00—Making machine elements
- B21K1/76—Making machine elements elements not mentioned in one of the preceding groups
- B21K1/766—Connecting rods
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J1/00—Preparing metal stock or similar ancillary operations prior, during or post forging, e.g. heating or cooling
- B21J1/06—Heating or cooling methods or arrangements specially adapted for performing forging or pressing operations
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor
- B21J5/002—Hybrid process, e.g. forging following casting
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor
- B21J5/02—Die forging; Trimming by making use of special dies ; Punching during forging
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K29/00—Arrangements for heating or cooling during processing
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
- C21D1/30—Stress-relieving
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/34—Methods of heating
- C21D1/42—Induction heating
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/009—Pearlite
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
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Abstract
The invention relates to a method for tempering waste heat after forging a non-quenched and tempered steel connecting rod of an engine, which comprises the working procedures of heating, roll forging and die forging, and also comprises the following steps of S1 trimming: cutting off redundant burrs and metal connecting sheets of the forged piece after forging; s2 thermal correction: placing the trimmed forge piece in a correction die for thermal correction; s3 temperature control and cooling: placing the forge piece after thermal correction on a conveying belt, and cooling the forge piece to be below the Ar1 cooling transformation point so as to ensure that the content of ferrite in the forge piece is 20-30%; s4 waste heat tempering: placing the forging with the temperature controlled and cooled in a heat preservation device for tempering and heat preservation of waste heat, wherein the heat preservation temperature is 600-; s5 natural cooling: and (4) placing the forged piece after the residual heat tempering at room temperature for natural cooling to obtain a finished product. The method has the advantages of low energy consumption and low cost, and the prepared engine non-quenched and tempered steel connecting rod has high quality, so that the condition of rework and repair can be effectively reduced, and the production efficiency is improved.
Description
Technical Field
The invention relates to the technical field of non-quenched and tempered connecting rods of engines, in particular to a method for tempering a non-quenched and tempered steel connecting rod of an engine by using waste heat after forging.
Background
The connecting rod is one of main parts in an automobile engine, is mainly used for connecting a piston and a crankshaft of the engine and bears certain alternating loads such as compression, tension and the like, so that the connecting rod of the engine is required to have good mechanical property.
At present, in the process of preparing the connecting rod, a temperature control and cooling treatment process is generally adopted after the connecting rod is forged, and due to the limitation of conditions such as unstable forging process, climate change, temperature entering a fan and the like, the connecting rod is often scrapped due to high hardness, low hardness, uneven hardness, unqualified mechanical performance, large residual stress and the like after the connecting rod is forged, or the problems of high expansion and breakage slag rate of the connecting rod, rework and repair, waste products and the like caused by secondary tempering and the like are required to be carried out, so that the cost of the connecting rod is increased sharply, the production efficiency and the quality of the connecting rod are influenced, great hidden dangers are brought to an engine, and the technical problem which needs to be solved urgently in the connecting rod industry is solved.
Disclosure of Invention
The invention aims to solve the technical problem of providing a method for tempering the forged waste heat of the non-quenched and tempered steel connecting rod of the engine, which has low energy consumption and low cost, can prepare a high-quality connecting rod, thereby reducing the condition of rework and repair and effectively improving the production efficiency.
In order to solve the problems, the technical scheme adopted by the invention is as follows:
in a first aspect, a method for tempering after forging residual heat of a non-quenched and tempered steel connecting rod of an engine is provided, which comprises the following steps: the process comprises the following steps of heating, roll forging and die forging:
s1, trimming: cutting off redundant burrs and metal connecting sheets of the forged piece after forging;
s2, thermal correction: placing the trimmed forge piece in a correction die for thermal correction;
s3, temperature control and cold control: placing the forge piece after thermal correction on a conveying belt, and cooling the forge piece to be below the Ar1 cooling transformation point so as to ensure that the content of ferrite in the forge piece is 20-30%;
s4, tempering by waste heat: placing the forging with the temperature controlled and cooled in a heat preservation device for tempering and heat preservation of waste heat, wherein the heat preservation temperature is 600-;
s5, natural cooling: and (4) placing the forged piece after the residual heat tempering at room temperature for natural cooling to obtain a finished product.
As a further improvement of the invention, in step S3, the temperature of the forge piece after thermal correction is 850-900 ℃.
As a further improvement of the invention, the temperature in the heating process is 1230-.
As a further improvement of the invention, the temperature of the trimming process is 1040-.
As a further improvement of the invention, in the roll forging procedure, a roll forging machine of ZGD-370 or ZGD-460 type is adopted for transverse rolling to obtain the dumbbell-shaped die forging blank with a round rod in the middle and approximately spherical two ends, so that the blank material is distributed reasonably.
As a further improvement of the invention, after the roll forging process, the temperature is reduced to 1110-1130 ℃ and then the die forging process is carried out.
As a further improvement of the invention, the die forging process is to carry out transverse die forging on the dumbbell-shaped die forging blank, and after die forging, the total deformation of the I-shaped rib part of the connecting rod is 75-80%, the total deformation of the large head part is 35-40%, and the total deformation of the small head part is 40-45%.
In a second aspect, there is provided a non-quenched and tempered steel connecting rod for an engine, made by the method of the first aspect.
As a further improvement of the invention, the connecting rod is made of any one of 36MnVS4 and C70S 6.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in:
according to the method for tempering the non-quenched and tempered steel connecting rod of the engine by using the waste heat after forging, the heating temperature and the Ar1 point temperature are determined by using the iron-carbon phase diagram and the steel cooling curve, and alloy elements are fully dissolved into an austenite structure in the heating process, so that the mechanical strength of the prepared connecting rod is improved.
The waste heat after the controlled cooling of the forged connecting rod is utilized to fully preserve heat of the forged connecting rod piece at the temperature of 600-680 ℃, so that the hardness of a workpiece is controlled in a proper range, the uniformity of the hardness is ensured, the structural stress and the thermal stress of the forged connecting rod piece are eliminated, the deformation and the slag dropping of the connecting rod in the cracking process and the machining process are reduced, and the roundness of the connecting rod assembly is ensured.
In the heating process, medium-frequency induction heating is adopted, the heating temperature is controlled at 1230-1255 ℃, alloy elements are fully dissolved in austenite, and a foundation is laid for improving the mechanical strength of the connecting rod; in the roll forging process, a roll forging machine of a ZGD-370 or ZGD-460 model is adopted to manufacture a die forging blank, so that the connecting rod forms a resultant metal streamline; in the die forging process, the metal is formed by adopting a pre-forging mode and a finish forging mode; after the thermal correction process, the deformation in the metal forming process can be eliminated, and the flatness and symmetry of the connecting rod forging are ensured; in the temperature control and control cooling process, an austenite structure can be rapidly transformed into pearlite and ferrite, and the ferrite content is ensured to be 20-30%; in the waste heat tempering process, the structure stress and the thermal stress generated by forging can be removed from the forge piece, and the consistency of hardness is also ensured.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail and fully with reference to the following embodiments.
The following examples 1 and 2 are described with reference to the production of a tie rod of material 36MnVS 4.
Example 1
Heating the blank to 1230 ℃ in a medium-frequency induction heating mode; placing the heated blank in a roll forging machine of ZGD-370 model for transverse rolling to obtain a dumbbell-shaped die forging blank with a round rod in the middle and approximately spherical two ends, and reasonably distributing the blank material, wherein the roll forging process temperature is 1170 ℃; after roll forging, carrying out a die forging process after the temperature of a die forging blank is reduced to 1130 ℃, namely, carrying out transverse die forging on the dumbbell-shaped die forging blank, wherein the die forging process comprises a pre-forging process and a final forging process, wherein the temperature of the pre-forging process is 1130 ℃, the temperature of the final forging process is 1100 ℃, the total deformation of the I-shaped rib part of the connecting rod after die forging is 75-80%, the total deformation of the large head part is 35-40%, and the total deformation of the small head part is 40-45%; trimming the formed forging piece after die forging to cut off redundant burrs and metal connecting skin, wherein the temperature of the trimming process is 1070 ℃; placing the trimmed forge piece in a correction die for thermal correction, wherein the temperature of a thermal correction process is 1020 ℃, and the temperature of the forge piece subjected to thermal correction is 900 ℃; and (3) placing the forge piece subjected to thermal correction on a conveying belt, cooling the forge piece to be below the Ar1 cooling transformation point so that the austenite structure is rapidly transformed into pearlite and ferrite, placing the cooled forge piece in a heat preservation device, preserving the heat at 600 ℃ for 5 hours, and finally naturally cooling to obtain a finished connecting rod.
The heat preservation device comprises a cylinder body with an opening at the upper end and a cover body covering the opening of the cylinder body, heat preservation layers are arranged on the outer side of the cylinder body and the outer side of the cover body, a through hole for the forge piece to pass through is further formed in the cover body, and the forge piece enters the cylinder body through the through hole.
Example 2
Heating the blank to 1255 ℃ by adopting a medium-frequency induction heating mode, then placing the heated blank in a roll forging machine of ZGD-460 model for transverse rolling to obtain a dumbbell-shaped die forging blank with a round rod in the middle and approximately spherical two ends, and leading the blank material to be reasonably distributed, wherein the temperature of the roll forging process is 1170 ℃; after roll forging, carrying out die forging process after the temperature of a die forging blank is reduced to 1110 ℃, namely, carrying out transverse die forging on the dumbbell-shaped die forging blank, wherein the die forging process comprises a pre-forging process and a final forging process, the temperature of the pre-forging process is 1110 ℃, the temperature of the final forging process is 1080 ℃, the total deformation of the I-shaped rib part of the connecting rod after die forging is 75-80%, the total deformation of the large head part is 35-40%, and the total deformation of the small head part is 40-45%; trimming the formed forging piece after die forging to cut off redundant burrs and metal connecting sheets, wherein the temperature of the trimming process is 1040 ℃; placing the trimmed forge piece in a correction die for thermal correction, wherein the temperature of a thermal correction process is 940 ℃, and the temperature of the forge piece subjected to thermal correction is 850 ℃; and (3) placing the forge piece subjected to thermal correction on a conveying belt, cooling the forge piece to be below the Ar1 cooling transformation point so that the austenite structure is rapidly transformed into pearlite and ferrite, placing the cooled forge piece in a heat preservation device, preserving the heat at 650 ℃ for 4.5 hours, and finally naturally cooling to obtain a finished connecting rod.
The heat preservation device comprises a cylinder body with an opening at the upper end and a cover body covering the opening of the cylinder body, heat preservation layers are arranged on the outer side of the cylinder body and the outer side of the cover body, a through hole for the forge piece to pass through is further formed in the cover body, and the forge piece enters the cylinder body through the through hole.
The following examples 3 and 4 are described with reference to the production of a connecting rod made of C70S 6.
Example 3
Heating the blank to 1240 ℃ by adopting a medium-frequency induction heating mode, then placing the heated blank in a roll forging machine of ZGD-370 model for transverse rolling to obtain a dumbbell-shaped die forging blank with a round rod in the middle and approximately spherical two ends, and reasonably distributing the blank material, wherein the temperature of the roll forging process is 1150 ℃; after roll forging, carrying out die forging process after the temperature of a die forging blank is reduced to 1110 ℃, namely, carrying out transverse die forging on the dumbbell-shaped die forging blank, wherein the die forging process comprises a pre-forging process and a final forging process, the temperature of the pre-forging process is 1110 ℃, the temperature of the final forging process is 1080 ℃, the total deformation of the I-shaped rib part of the connecting rod after die forging is 75-80%, the total deformation of the large head part is 35-40%, and the total deformation of the small head part is 40-45%; trimming the formed forging piece after die forging to cut off redundant burrs and metal connecting sheets, wherein the temperature of the trimming process is 1040 ℃; placing the trimmed forge piece in a correction die for thermal correction, wherein the temperature of a thermal correction process is 940 ℃, and the temperature of the forge piece subjected to thermal correction is 850 ℃; and (3) placing the forge piece subjected to thermal correction on a conveying belt, cooling the forge piece to below the Ar1 cooling transformation point so that the austenite structure is rapidly transformed into pearlite and ferrite, placing the cooled forge piece in a heat preservation device, preserving the heat at 680 ℃ for 4 hours, and finally naturally cooling to obtain a finished connecting rod.
The heat preservation device comprises a cylinder body with an opening at the upper end and a cover body covering the opening of the cylinder body, heat preservation layers are arranged on the outer side of the cylinder body and the outer side of the cover body, a through hole for the forge piece to pass through is further formed in the cover body, and the forge piece enters the cylinder body through the through hole.
Example 4
Heating the blank to 1250 ℃ by adopting a medium-frequency induction heating mode, then placing the heated blank in a roll forging machine of ZGD-460 model for transverse rolling to obtain a dumbbell-shaped die forging blank with a round rod in the middle and approximately spherical two ends, and reasonably distributing the blank material, wherein the temperature of the roll forging process is 1160 ℃; after roll forging, carrying out a die forging process after the temperature of a die forging blank is reduced to 1120 ℃, namely carrying out transverse die forging on the dumbbell-shaped die forging blank, wherein the die forging process comprises a pre-forging process and a final forging process, wherein the temperature of the pre-forging process is 1120 ℃, the temperature of the final forging process is 1090 ℃, the total deformation of the I-shaped rib part of the connecting rod after die forging is 75-80%, the total deformation of the large head part is 35-40%, and the total deformation of the small head part is 40-45%; trimming the formed forging piece after die forging to cut off redundant burrs and metal connecting sheets, wherein the trimming process temperature is 1060 ℃; placing the trimmed forge piece in a correction die for thermal correction, wherein the temperature of a thermal correction process is 1000 ℃, and the temperature of the forge piece subjected to thermal correction is 875 +/-25 ℃; and (3) placing the forge piece subjected to thermal correction on a conveying belt, cooling the forge piece to be below the Ar1 cooling transformation point so that the austenite structure is rapidly transformed into pearlite and ferrite, placing the cooled forge piece in a heat preservation device, preserving the heat at 620 ℃ for 4.8 hours, and finally naturally cooling to obtain a finished connecting rod.
The heat preservation device comprises a cylinder body with an opening at the upper end and a cover body covering the opening of the cylinder body, heat preservation layers are arranged on the outer side of the cylinder body and the outer side of the cover body, a through hole for the forge piece to pass through is further formed in the cover body, and the forge piece enters the cylinder body through the through hole.
The following comparative examples 1 and 2 are described by taking the example of producing a tie rod of material 36MnVS 4.
Comparative example 1
Heating the blank to 1255 ℃ by adopting a medium-frequency induction heating mode, then placing the heated blank in a roll forging machine of ZGD-370 type for transverse rolling to obtain a dumbbell-shaped die forging blank with a round rod in the middle and approximately spherical two ends, and leading the blank material to be reasonably distributed, wherein the roll forging process temperature is 1170 ℃; after roll forging, carrying out a die forging process after the temperature of a die forging blank is reduced to 1130 ℃, namely, carrying out transverse die forging on the dumbbell-shaped die forging blank, wherein the die forging process comprises a pre-forging process and a final forging process, wherein the temperature of the pre-forging process is 1130 ℃, the temperature of the final forging process is 1100 ℃, the total deformation of the I-shaped rib part of the connecting rod after die forging is 75-80%, the total deformation of the large head part is 35-40%, and the total deformation of the small head part is 40-45%; trimming the formed forging piece after die forging to cut off redundant burrs and metal connecting skin, wherein the temperature of the trimming process is 1070 ℃; placing the trimmed forge piece in a correction die for thermal correction, wherein the temperature of a thermal correction process is 1020 ℃, and the temperature of the forge piece subjected to thermal correction is 900 ℃; and (3) placing the forge piece after thermal correction on a conveying belt to be cooled to room temperature, finally heating the forge piece to 600 ℃ through an electric furnace, preserving heat for 5 hours, and naturally cooling to obtain a finished connecting rod product.
Comparative example 2
Heating the blank to 1255 ℃ by adopting a medium-frequency induction heating mode, then placing the heated blank in a roll forging machine of ZGD-460 model for transverse rolling to obtain a dumbbell-shaped die forging blank with a round rod in the middle and approximately spherical two ends, and leading the blank material to be reasonably distributed, wherein the temperature of the roll forging process is 1170 ℃; after roll forging, carrying out die forging process after the temperature of a die forging blank is reduced to 1110 ℃, namely, carrying out transverse die forging on the dumbbell-shaped die forging blank, wherein the die forging process comprises a pre-forging process and a final forging process, the temperature of the pre-forging process is 1110 ℃, the temperature of the final forging process is 1080 ℃, the total deformation of the I-shaped rib part of the connecting rod after die forging is 75-80%, the total deformation of the large head part is 35-40%, and the total deformation of the small head part is 40-45%; trimming the formed forging piece after die forging to cut off redundant burrs and metal connecting sheets, wherein the temperature of the trimming process is 1040 ℃; placing the trimmed forge piece in a correction die for thermal correction, wherein the temperature of a thermal correction process is 940 ℃, and the temperature of the forge piece subjected to thermal correction is 850 ℃; and (3) placing the forge piece after thermal correction on a conveyor belt, cooling to room temperature, finally heating the forge piece to 650 ℃ through an electric furnace, preserving heat for 4.5 hours, and naturally cooling to obtain a connecting rod finished product.
The following comparative examples 3 to 5 are described by taking the example of producing a tie rod of the material C70S 6.
Comparative example 3
Heating the blank to 1240 ℃ by adopting a medium-frequency induction heating mode, then placing the heated blank in a roll forging machine of ZGD-370 model for transverse rolling to obtain a dumbbell-shaped die forging blank with a round rod in the middle and approximately spherical two ends, and reasonably distributing the blank material, wherein the temperature of the roll forging process is 1150 ℃; after roll forging, carrying out die forging process after the temperature of a die forging blank is reduced to 1110 ℃, namely, carrying out transverse die forging on the dumbbell-shaped die forging blank, wherein the die forging process comprises a pre-forging process and a final forging process, the temperature of the pre-forging process is 1110 ℃, the temperature of the final forging process is 1080 ℃, the total deformation of the I-shaped rib part of the connecting rod after die forging is 75-80%, the total deformation of the large head part is 35-40%, and the total deformation of the small head part is 40-45%; trimming the formed forging piece after die forging to cut off redundant burrs and metal connecting sheets, wherein the temperature of the trimming process is 1040 ℃; placing the trimmed forge piece in a correction die for thermal correction, wherein the temperature of a thermal correction process is 940 ℃, and the temperature of the forge piece subjected to thermal correction is 850 ℃; and (3) placing the forge piece after thermal correction on a conveyor belt, cooling to room temperature, finally heating the forge piece to 680 ℃ through an electric furnace, preserving heat for 4 hours, and naturally cooling to obtain a connecting rod finished product.
Comparative example 4
Heating the blank to 1250 ℃ by adopting a medium-frequency induction heating mode, then placing the heated blank in a roll forging machine of ZGD-460 model for transverse rolling to obtain a dumbbell-shaped die forging blank with a round rod in the middle and approximately spherical two ends, and reasonably distributing the blank material, wherein the temperature of the roll forging process is 1160 ℃; after roll forging, carrying out a die forging process after the temperature of a die forging blank is reduced to 1120 ℃, namely carrying out transverse die forging on the dumbbell-shaped die forging blank, wherein the die forging process comprises a pre-forging process and a final forging process, wherein the temperature of the pre-forging process is 1120 ℃, the temperature of the final forging process is 1090 ℃, the total deformation of the I-shaped rib part of the connecting rod after die forging is 75-80%, the total deformation of the large head part is 35-40%, and the total deformation of the small head part is 40-45%; trimming the formed forging piece after die forging to cut off redundant burrs and metal connecting sheets, wherein the trimming process temperature is 1060 ℃; placing the trimmed forge piece in a correction die for thermal correction, wherein the temperature of a thermal correction process is 1000 ℃, and the temperature of the forge piece subjected to thermal correction is 875 ℃; and (3) placing the forge piece after thermal correction on a conveying belt, cooling to room temperature, finally heating the forge piece to 620 ℃ through an electric furnace, preserving heat for 4.8 hours, and naturally cooling to obtain a connecting rod finished product.
Experimental example 1: mechanical Property test
The hardness, tensile strength, yield strength, elongation and reduction of area of the finished connecting rods obtained in examples 1 to 4 and comparative examples 1 to 4 were measured, respectively, and the results are shown in table 1.
As can be seen from table 1, the tensile strength, yield strength and elongation of the finished connecting rod obtained by the method of the present invention are all increased and the reduction of area is reduced without changing the hardness, and as for the tensile strength of the finished connecting rod, example 1 is increased by 18.1% compared to example 1, example 2 is increased by 17.5% compared to example 2, example 3 is increased by 16.6% compared to example 3, and example 4 is increased by 15.3% compared to example 4. Therefore, the connecting rod obtained by the method provided by the invention has higher mechanical properties at lower hardness.
Experimental example 2: internal stress value test
The internal stress values of the finished connecting rods obtained in examples 1 to 4 and comparative examples 1 to 4 were measured, respectively, and the results are shown in table 2.
As can be seen from Table 2, after the method provided by the invention is adopted, the internal stress value of the obtained connecting rod finished product is reduced to a value lower than 0.03mm from an initial value of 0.05 mm-0.07 mm, and the condition of expansion fracture deformation of the connecting rod can be effectively reduced.
Experimental example 3: test of cracking and slag dropping rate
The cracking and slag dropping rates of the finished connecting rods obtained in examples 1 to 4 and comparative examples 1 to 4 were measured, respectively, and the results are shown in table 3.
As can be seen from Table 3, after the method provided by the invention is adopted, the cracking and slag dropping rate of the obtained connecting rod finished product is reduced from 0.48% to a value lower than 0.1%, and the rejection rate is reduced.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (8)
1. A method for tempering after forging residual heat of a non-quenched and tempered steel connecting rod of an engine is characterized in that the connecting rod is made of any one of 36MnVS4 and C70S6, and the method comprises the following steps: the process comprises the following steps of heating, roll forging and die forging:
s1, trimming: cutting off redundant burrs and metal connecting sheets of the forged piece after forging;
s2, thermal correction: placing the trimmed forge piece in a correction die for thermal correction;
s3, temperature control and cold control: placing the forge piece after thermal correction on a conveying belt, and cooling the forge piece to be below the Ar1 cooling transformation point so as to ensure that the content of ferrite in the forge piece is 20-30%;
s4, tempering by waste heat: placing the forging with the temperature controlled and cooled in a heat preservation device for tempering and heat preservation of waste heat, wherein the heat preservation temperature is 600-;
s5, natural cooling: and (4) placing the forged piece after the residual heat tempering at room temperature for natural cooling to obtain a finished product.
2. The method for tempering the forged waste heat of the non-quenched and tempered steel connecting rod of the engine according to claim 1, wherein in the step S3, the temperature of the forge piece after thermal correction is 850-900 ℃.
3. The method for tempering the connecting rod of non-quenched and tempered steel of engine with residual heat after forging as claimed in claim 1, wherein the temperature in the heating process is 1230-.
4. The method as claimed in claim 1, wherein the trimming process temperature is 1040 ℃ and the thermal correction process temperature is 940 ℃ and 1020 ℃.
5. The method for tempering the non-quenched and tempered steel connecting rod of the engine by the residual heat after forging according to claim 1, wherein in the roll forging process, a roll forging machine of ZGD-370 or ZGD-460 type is adopted for transverse rolling to obtain a dumbbell-shaped die forging blank with a round rod in the middle and approximately spherical ends.
6. The method for tempering by waste heat after forging of the non-quenched and tempered steel connecting rod of the engine as claimed in claim 5, wherein the step of die forging is performed after the temperature of the die forging blank is reduced to 1110-1130 ℃ after the step of roll forging.
7. The method for tempering the non-quenched and tempered steel connecting rod of the engine by the waste heat after forging according to claim 6, wherein the forging step is transverse forging of the dumbbell-shaped forging blank, and the total deformation of the I-shaped rib part of the connecting rod after forging is 75-80%, the total deformation of the large head part is 35-40%, and the total deformation of the small head part is 40-45%.
8. An engine non-quenched and tempered steel connecting rod made by the method of any one of claims 1-7.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58138537A (en) * | 1982-02-12 | 1983-08-17 | Nippon Steel Corp | Manufacture of hot forging nut |
| CN1523241A (en) * | 2003-02-19 | 2004-08-25 | 日产自动车株式会社 | High-strength connecting rod and method of producing same |
| CN102586559A (en) * | 2011-01-05 | 2012-07-18 | 南京工程学院 | Manufacture technology of high-toughness microalloyed non-quenched and tempered steel forging |
| CN102989982A (en) * | 2012-08-22 | 2013-03-27 | 昌利锻造有限公司 | Forging method of driving shaft for gearbox |
| CN103934408A (en) * | 2014-03-20 | 2014-07-23 | 白城中一精锻股份有限公司 | Air cooling method for forged non-quenched and tempered steel automobile engine connecting rod workblanks |
| CN110756583A (en) * | 2019-09-11 | 2020-02-07 | 南京钢铁股份有限公司 | Preparation method of non-quenched and tempered steel and method for preparing fine-grained forging by using same |
-
2020
- 2020-04-13 CN CN202010285561.6A patent/CN111408681B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58138537A (en) * | 1982-02-12 | 1983-08-17 | Nippon Steel Corp | Manufacture of hot forging nut |
| CN1523241A (en) * | 2003-02-19 | 2004-08-25 | 日产自动车株式会社 | High-strength connecting rod and method of producing same |
| CN102586559A (en) * | 2011-01-05 | 2012-07-18 | 南京工程学院 | Manufacture technology of high-toughness microalloyed non-quenched and tempered steel forging |
| CN102989982A (en) * | 2012-08-22 | 2013-03-27 | 昌利锻造有限公司 | Forging method of driving shaft for gearbox |
| CN103934408A (en) * | 2014-03-20 | 2014-07-23 | 白城中一精锻股份有限公司 | Air cooling method for forged non-quenched and tempered steel automobile engine connecting rod workblanks |
| CN110756583A (en) * | 2019-09-11 | 2020-02-07 | 南京钢铁股份有限公司 | Preparation method of non-quenched and tempered steel and method for preparing fine-grained forging by using same |
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Denomination of invention: A Method for Afterheat Tempering of Engine Non quenched and Tempered Steel Connecting Rods after Forging Effective date of registration: 20230710 Granted publication date: 20220412 Pledgee: Xingtai Branch of Industrial Bank Co.,Ltd. Pledgor: NANGONG JINGQIANG CONNECTING ROD Co.,Ltd. Registration number: Y2023980047948 |