CN110964898A - Induction quenching process for hardening alloy cast iron camshaft by using compressed air - Google Patents
Induction quenching process for hardening alloy cast iron camshaft by using compressed air Download PDFInfo
- Publication number
- CN110964898A CN110964898A CN201911328950.6A CN201911328950A CN110964898A CN 110964898 A CN110964898 A CN 110964898A CN 201911328950 A CN201911328950 A CN 201911328950A CN 110964898 A CN110964898 A CN 110964898A
- Authority
- CN
- China
- Prior art keywords
- heating
- camshaft
- quenching
- seconds
- induction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/30—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for crankshafts; for camshafts
-
- 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
- C21D1/06—Surface hardening
- C21D1/09—Surface hardening by direct application of electrical or wave energy; by particle radiation
- C21D1/10—Surface hardening by direct application of electrical or wave energy; by particle radiation by electric induction
-
- 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
- C21D1/18—Hardening; Quenching with or without subsequent tempering
-
- 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
- C21D1/56—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
- C21D1/613—Gases; Liquefied or solidified normally gaseous material
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/06—Cast-iron alloys containing chromium
- C22C37/08—Cast-iron alloys containing chromium with nickel
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/10—Cast-iron alloys containing aluminium or silicon
-
- 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
- Y02P10/20—Recycling
-
- 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
Abstract
The invention provides an induction quenching process for hardening an alloy cast iron camshaft by using compressed air, which comprises the following steps of: s1, preheating: in the first stage, after the camshaft is heated to the temperature of 180-210 ℃ by induction, the heating is suspended for 2-5 seconds; in the second stage, after the camshaft is heated to 550-600 ℃, the heating is suspended for 2-5 seconds; in the third stage, after the camshaft is heated to the temperature of 810-850 ℃, the heating is suspended for 2-5 seconds; the heating rate of the three stages is 40-50 ℃/second; s2, heating to a quenching temperature: induction heating the camshaft preheated in the step S1 to 900-940 ℃ at the heating rate of 40-50 ℃/second; s3, quenching: quenching the camshaft by using compressed air with the pressure of 0.4-0.5MPa as a quenching medium, and cooling the camshaft to 300 ℃ below 250 ℃; s4, residual temperature tempering. The alloy cast iron camshaft product quenched by the process method of the invention can not generate cracks in the quenching process, and the hardness index after quenching can meet the technical requirements, thereby reducing the rejection rate of the product and greatly saving the production cost.
Description
Technical Field
The invention relates to an induction quenching process for hardening an alloy cast iron camshaft by using compressed air, belonging to the technical field of heat treatment.
Background
The alloy cast iron camshaft is an important moving part in an internal combustion engine, the market demand is large, and after induction quenching, the wear resistance of the alloy cast iron camshaft is obviously superior to that of a steel product, so that induction quenching of the alloy cast iron camshaft is an indispensable process. However, in the traditional induction quenching heat treatment process, cracks are inevitably generated and are divided into two types, one is heating cracks, and the other is quenching cracks. Both cracks are mainly concentrated at the lift locations on both sides of the cam lobe tip. Statistics shows that when the camshaft is subjected to induction quenching by adopting the traditional process, the rate of cracks generated at the lift position of the camshaft in the heating stage is 35-40%; in the quenching and cooling stage, no matter quenching oil or water-soluble quenching agent is adopted for quenching, quenching stress is too large in the cooling process and exceeds the ultimate strength of workpieces, so that quenching cracks appear on large batches of workpieces, the rejection rate is high due to the adoption of the traditional quenching process, and huge economic loss is caused to enterprises. According to statistics, the crack rate generated by water quenching is 100%, the crack rate generated by quenching with a water-soluble quenching agent with the concentration of 10-15% is 30-35%, the quenching crack rate of 10-15% is also achieved by spraying and cooling with a water-based quenching agent, and after heating, if air cooling quenching is adopted, although the workpiece can not crack, the hardness index requirement in the technical requirement can not be achieved. Therefore, the rejection rate of the traditional induction quenching process is extremely high, the production cost is greatly increased, great trouble is caused to enterprises, uncertain hidden quality troubles still exist even if qualified products are detected, and the quality credit of the enterprises is directly influenced.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide an induction quenching process for quenching an alloy cast iron camshaft by using compressed air, the alloy cast iron camshaft quenched by using the process method cannot generate cracks in the quenching process, the hardness index after quenching can meet the technical requirements, the rejection rate of the product is reduced, and the production cost is greatly saved.
In order to achieve the purpose, the invention adopts the technical scheme that:
an induction hardening process for hardening an alloy cast iron camshaft using compressed air, the alloy cast iron having chemical composition (%): c, 3.10-3.25; mn 0.75-0.95; 2.20-2.40 of Si; p is less than or equal to 0.15; s is less than or equal to 0.20; 0.20-0.35 of Ni; 1.35-1.55 parts of Cr; 0.35-0.55 percent of Mo; the method comprises the following steps:
s1, preheating: in the first stage, the camshaft is induction heated to 180-210 ℃ at the heating rate of 40-50 ℃/second, and then heating is suspended for 2-5 seconds; in the second stage, the camshaft is induction heated to 550-600 ℃ at the heating rate of 40-50 ℃/second, and then heating is suspended for 2-5 seconds; in the third stage, the camshaft is induction heated to 810-850 ℃ at the heating rate of 40-50 ℃/second, and then heating is suspended for 2-5 seconds;
s2, heating to a quenching temperature: induction heating the camshaft preheated in the step S1 to 900-940 ℃ at the heating rate of 40-50 ℃/second;
s3, quenching: quenching the camshaft heated in the step S2 by using compressed air with the pressure of 0.4-0.5MPa as a quenching medium, and cooling the camshaft to 250-300 ℃;
s4, residual temperature tempering: and (4) standing the camshaft quenched in the step S3 for 50-60 minutes at room temperature, and finishing the tempering process by using the residual temperature after quenching.
The technical scheme of the invention is further improved as follows:
the first-stage heating temperature in the step S1 is preferably 190 +/-10 ℃; the heating temperature of the second stage is preferably 570 +/-10 ℃; the heating temperature in the third stage is preferably 830 +/-10 ℃.
The heating temperature in step S2 is preferably 920 ± 10 ℃.
The time for suspending heating in the three stages in step S1 is preferably 3 seconds.
According to the technical scheme provided by the invention, the induction quenching process for quenching the alloy cast iron camshaft by using compressed air is characterized in that the induction quenching process is preheated before the camshaft is heated to the quenching temperature, and the preheating is carried out in three stages, namely a stage of 210 ℃ for 180 DEG, a stage of 600 ℃ for 550 DEG and a stage of 850 ℃ for 810 DEG, and the preheating is carried out in multiple stages, so that the phenomenon that the temperature difference between the inside and the outside of the camshaft is too large due to the fact that the temperature is raised in place once can be avoided, and stress cracks caused by too large temperature difference can be avoided; heating at a heating rate of 40-50 ℃/second during preheating, and also avoiding stress cracks caused by an excessively high heating rate; in order to make the internal and external temperatures of the camshaft more uniform, the invention adopts a pause heating mode at the end of each preheating stage to reduce the temperature difference and reduce the possibility of cracking. When the steel is heated to the quenching temperature, the temperature stress is prevented from generating cracks by controlling the heating rate. In the quenching stage, compressed air with the pressure of 0.4-0.5MPa is used as a quenching medium, the camshaft is cooled to 300 ℃ at the temperature of 250-. The quenched camshaft stands still for 50-60 minutes at room temperature, and the residual heat after quenching is utilized to complete the tempering process, so that the residual heat of the camshaft is completely utilized in the process, no energy is consumed, the cost is saved, and the product has good performance indexes.
Drawings
FIG. 1 is a schematic process flow diagram of the present invention.
Detailed Description
The invention will be further illustrated with reference to specific examples:
the technical requirements of the camshaft of the embodiment of the invention are as follows:
(1) peach tip and lift part hardness: 58HRC MIN; hardness of base circle part: 55HRC MIN.
(2) The depth of the effective hardening layer is required to be more than or equal to 5.5mm, and 50HRC is taken as a boundary.
(3) And martensite 4-5 grade.
Whether the camshaft workpiece after the heat treatment is cracked or not is subject to magnetic powder flaw detection.
Example 1, 30 camshaft workpieces were induction quenched as follows:
s1, preheating: firstly, induction heating the camshaft to 190 +/-10 ℃, stopping heating for 2 seconds to ensure that a heating part is uniformly heated, then induction heating to 560 +/-10 ℃, and stopping heating for 2 seconds; then heating the camshaft to 820 +/-10 ℃ by induction heating, and stopping heating for 2 seconds; the heating rate of the three stages is 40-50 ℃/s;
s2, heating to a quenching temperature: induction heating the camshaft preheated in the step S1 to 900 +/-10 ℃ at the heating rate of 40-50 ℃/second;
s3, quenching: quenching the camshaft heated in the step S2 by using compressed air with the pressure of 0.4-0.5MPa as a quenching medium for 50 seconds, and cooling the camshaft to 250-280 ℃;
s4, residual temperature tempering: and (4) standing the camshaft quenched in the step S3 for 50 minutes at room temperature, and finishing the tempering process by using the residual temperature after quenching.
Example 2, 30 camshaft workpieces were induction quenched as follows:
s1, preheating: firstly, heating the camshaft to 200 +/-10 ℃ by induction for 5 seconds, ensuring that the heating part is heated uniformly, then heating the camshaft to 590 +/-10 ℃ by induction, and stopping heating for 5 seconds; then the camshaft is heated to 840 +/-10 ℃ by induction, and the heating is stopped for 5 seconds; the heating rate of the three stages is 40-50 ℃/s;
s2, heating to a quenching temperature: induction heating the camshaft preheated in the step S1 to 930 +/-10 ℃ at the heating rate of 40-50 ℃/second;
s3, quenching: quenching the camshaft heated in the step S2 by using compressed air with the pressure of 0.4-0.5MPa as a quenching medium for 40 seconds, and cooling the camshaft to 270-300 ℃;
s4, residual temperature tempering: and (4) standing the camshaft quenched in the step S3 for 60 minutes at room temperature, and finishing the tempering process by using the residual temperature after quenching.
Example 3, 30 camshaft workpieces were induction quenched as follows:
s1, preheating: firstly, heating the camshaft to 190 +/-10 ℃ by induction heating, stopping heating for 3 seconds to ensure that a heating part is uniformly heated, then heating to 570 +/-10 ℃ by induction heating, and stopping heating for 3 seconds; then the camshaft is heated to 830 +/-10 ℃ by induction, and the heating is stopped for 3 seconds; the heating rate of the three stages is 40-50 ℃/s;
s2, heating to a quenching temperature: induction heating the camshaft preheated in the step S1 to 920 +/-10 ℃ at the heating rate of 40-50 ℃/second;
s3, quenching: quenching the camshaft heated in the step S2 by using compressed air with the pressure of 0.4-0.5MPa as a quenching medium for 40 seconds, and cooling the camshaft to 260-290 ℃;
s4, residual temperature tempering: and (4) standing the camshaft quenched in the step S3 for 50 minutes at room temperature, and finishing the tempering process by using the residual temperature after quenching.
The process flow diagram of the invention is shown in figure 1, after 90 camshaft products in total in the three embodiments are respectively subjected to induction quenching, no crack is generated through magnetic powder inspection, the performance of all the workpieces meets the technical requirement range of the alloy cast iron camshaft, the hardness reaches the standard, and the performance inspection result of embodiment 3 is taken as the best.
The induction quenching process method for quenching the alloy cast iron camshaft by using the compressed air is finally obtained through a plurality of tests, wherein the test process is as follows:
firstly, directly heating to a quenching temperature:
1. directly heating to 900-;
2. directly heating to 900-940 ℃ for quenching, wherein the heating rate is 60-70 ℃/second, and the product generates cracks;
3. directly heating to 900 ℃ and 940 ℃ for quenching, wherein the heating rate is 80-90 ℃/second, and the product generates cracks;
4. directly heating to 940 ℃ of 900 plus materials without quenching, wherein the heating rate is 40-50 ℃/s, and the product generates cracks;
5. directly heating to 940 ℃ of 900 plus materials without quenching, wherein the heating rate is 60-70 ℃/s, and the product generates cracks;
6. directly heating to 940 ℃ of 900 plus temperature without quenching, wherein the heating rate is 80-90 ℃/s, and the product generates cracks;
according to the test results, the heating process is directly finished by heating once, and cracks can be generated in the heating process.
Preheating, and then heating to a quenching temperature:
7. preheating to 800-;
8. preheating to 800-;
9. preheating to 800-;
10. preheating to 600 ℃ of 550-;
11. preheating to 600 ℃ of 550-;
12. preheating to 600 ℃ of 550-;
according to the above test results, cracks were also generated when the entire heating was completed in two stages.
Thirdly, completing the preheating and temperature rising process in three sections, and reheating to the quenching temperature:
13. firstly heating to 210 ℃ at 180 ℃, then heating to 600 ℃ at 550 ℃, then carrying out induction heating on the camshaft to 850 ℃ at 810 ℃ at 940 ℃, wherein the heating rate is 40-50 ℃/s, and the product cracks are obviously reduced;
14. firstly heating to 210 ℃ at 180 ℃, then heating to 600 ℃ at 550 ℃, then carrying out induction heating on the camshaft to 850 ℃ at 810 ℃ at 940 ℃, wherein the heating rate is 60-70 ℃/s, and the product crack accounts for a relatively large proportion;
15. firstly heating to 210 ℃ at 180 ℃, then heating to 600 ℃ at 550 ℃, then induction heating the camshaft to 850 ℃ at 810 ℃ at 940 ℃ at the heating rate of 80-90 ℃/s, and the product cracks account for a relatively large percentage.
The results of the 13 th test were confirmed to be remarkable, and the test was conducted again in consideration of direct heating each time and no interval time between three sections, which may cause non-uniform heat conduction.
Fourthly, completing the preheating and temperature rising process in three sections, pausing heating at the end of each stage to ensure the uniformity of the heating part, and then rising the temperature to the quenching temperature:
16. heating to 180 ℃ and 210 ℃ first, and stopping heating for 3 seconds; heating to 550-600 ℃, and stopping heating for 3 seconds; then the camshaft is heated to 850 ℃ by induction, and the heating is stopped for 3 seconds; finally heating to 900 ℃ and 940 ℃, setting the heating rate to be 40-50 ℃/second, and ensuring that the product has no crack;
17. heating to 180 ℃ and 210 ℃ first, and stopping heating for 3 seconds; heating to 550-600 ℃, and stopping heating for 3 seconds; then the camshaft is heated to 850 ℃ by induction, and the heating is stopped for 3 seconds; finally heating to 900 ℃ and 940 ℃, wherein the heating rate is 60-70 ℃/s, and the product crack ratio is smaller;
18. heating to 180 ℃ and 210 ℃ first, and stopping heating for 3 seconds; heating to 550-600 ℃, and stopping heating for 3 seconds; then the camshaft is heated to 850 ℃ by induction, and the heating is stopped for 3 seconds; finally heating to 940 ℃ at the temperature of 900 ℃ and the heating rate of 80-90 ℃/second, and the product crack accounts for a relatively large proportion.
In the 16 th test, the step of stopping heating was added to ensure the uniformity of the temperature of the heated part, and in addition, the product had no cracks when the reasonable heating temperature and heating rate were matched.
Fifthly, completing the preheating and temperature rising process in three sections, pausing heating at the end of each stage to ensure the uniformity of a heating part, then rising the temperature to the quenching temperature, and quenching by adopting compressed air:
19. heating to 180 ℃ and 210 ℃ first, and stopping heating for 3 seconds; heating to 550-600 ℃, and stopping heating for 3 seconds; then the camshaft is heated to 850 ℃ by induction, and the heating is stopped for 3 seconds; finally heating to 900 ℃ and 940 ℃, wherein the heating rate is 40-50 ℃/second; quenching the product by using compressed air, wherein the quenching time is 30 seconds, cooling the camshaft to 300 ℃ at the pressure of 0.2-0.3MPa, and the surface hardness of the product is insufficient;
20. heating to 180 ℃ and 210 ℃ first, and stopping heating for 3 seconds; heating to 550-600 ℃, and stopping heating for 3 seconds; then the camshaft is heated to 850 ℃ by induction, and the heating is stopped for 3 seconds; finally heating to 900 ℃ and 940 ℃, wherein the heating rate is 40-50 ℃/second; quenching the product by using compressed air for 30 seconds, cooling the camshaft to 300 ℃ at the temperature of 250 ℃ and the pressure of the compressed air of 0.4-0.5MPa, and ensuring that the surface hardness of the product is insufficient;
21. heating to 180 ℃ and 210 ℃ first, and stopping heating for 3 seconds; heating to 550-600 ℃, and stopping heating for 3 seconds; then the camshaft is heated to 850 ℃ by induction, and the heating is stopped for 3 seconds; finally heating to 900 ℃ and 940 ℃, and setting the heating rate at 40-50 ℃/second; quenching the product by using compressed air for 30 seconds, cooling the camshaft to 300 ℃ at the pressure of 0.6-0.7MPa, and enabling the product to start to generate cracks;
22. heating to 180 ℃ and 210 ℃ first, and stopping heating for 3 seconds; heating to 550-600 ℃, and stopping heating for 3 seconds; then the camshaft is heated to 850 ℃ by induction, and the heating is stopped for 3 seconds; finally heating to 900 ℃ and 940 ℃, and setting the heating rate at 40-50 ℃/second; quenching the product by using compressed air for 40 seconds, cooling the camshaft to 300 ℃ at the temperature of 250 ℃ and 0.2-0.3MPa, wherein the surface hardness of the product is insufficient;
23. heating to 180 ℃ and 210 ℃ first, and stopping heating for 3 seconds; then heating to 550-600 ℃, and stopping heating for 3 seconds; then the camshaft is heated to 850 ℃ by induction, and the heating is stopped for 3 seconds; finally heating to 900 ℃ and 940 ℃, wherein the heating rate is 40-50 ℃/second; quenching the product by using compressed air for 40 seconds, cooling the camshaft to 300 ℃ at the temperature of 250 ℃ and the pressure of the compressed air of 0.4-0.5MPa, and ensuring that the surface hardness of the product is insufficient;
24. heating to 180 ℃ and 210 ℃ first, and stopping heating for 3 seconds; heating to 550-600 ℃, and stopping heating for 3 seconds; then the camshaft is heated to 850 ℃ by induction, and the heating is stopped for 3 seconds; finally heating to 900 ℃ and 940 ℃, wherein the heating rate is 40-50 ℃/second; quenching the product by using compressed air for 40 seconds, cooling the camshaft to 300 ℃ at the temperature of 250 ℃ and the pressure of the compressed air of 0.6-0.7MPa, and generating cracks on the product;
25. heating to 180 ℃ and 210 ℃ first, and stopping heating for 3 seconds; heating to 550-600 ℃, and stopping heating for 3 seconds; then the camshaft is heated to 850 ℃ by induction, and the heating is stopped for 3 seconds; finally heating to 900 ℃ and 940 ℃, wherein the heating rate is 40-50 ℃/second; quenching the product by using compressed air for 50 seconds, cooling the camshaft to 250-300 ℃, wherein the pressure of the compressed air is 0.2-0.3MPa, and the surface hardness of the product is insufficient;
26. heating to 180 ℃ and 210 ℃ first, and stopping heating for 3 seconds; heating to 550-600 ℃, and stopping heating for 3 seconds; then the camshaft is heated to 850 ℃ by induction, and the heating is stopped for 3 seconds; finally heating to 900 ℃ and 940 ℃, wherein the heating rate is 40-50 ℃/second; quenching the product by using compressed air for 50 seconds, cooling the camshaft to the temperature of 250 ℃ and 300 ℃, wherein the pressure of the compressed air is 0.4-0.5MPa, the product has no crack, and the surface hardness is qualified.
The principle of the induction quenching process for hardening the alloy cast iron camshaft by using compressed air provided by the invention is as follows: the traditional induction quenching process is high in heating power and high in workpiece temperature rise speed, an alloy cast iron camshaft is of a structure taking pearlite as a matrix due to extremely high content of carbon and alloy elements and asynchronism of crystallization process during casting, a large amount of flake graphite and alloy carbide with the mass fraction of about 15-20% are distributed on the matrix, the heat conduction performance is poor due to serious stress concentration of the flake graphite and high hardness and brittleness of the alloy carbide, the graphite, high alloy content and non-metallic inclusions in the alloy cast iron, the cross section change of a camshaft lifting part is large, stress concentration is easy to cause, cracks are inevitably generated when the thermal stress is larger than the tensile strength, cracking sound can be heard at about 500 ℃ in the traditional process, and in order to solve the problem, the heating process provided by the invention has the advantages that the heating speed is delayed, the induction heating power is reduced, the total heating time is increased, the temperature of the camshaft workpiece is more uniform, and no crack appears in the heating process of the cam workpiece after the heating is finished in the embodiment.
In the traditional induction quenching process, water, quenching oil or a water-soluble quenching agent is adopted for quenching, the cracking rate of a workpiece is high due to the fact that the casting is poor in heat conduction performance, more undissolved carbides exist in the casting, the plasticity is poor, and when the casting is cooled by a water-based medium, because the cooling speed is too high, austenite on the surface is quickly cooled to M s points, martensite transformation occurs, so that the volume is expanded, and at the moment, the secondary surface is in an austenite plastic state, and cracks cannot be generated. When the cooling is continued, the secondary surface undergoes martensite transformation and volume expansion, the generated structural stress is greater than the tensile strength of the surface martensite, and cracks begin to appear. The reason is also caused by the fact that the cooling medium cooling speed is too high, and the structural transformation of the alloy cast iron camshaft with poor heat conductivity is not synchronous, compressed gas with the pressure of 0.4-0.5MP is used for cooling for 40-50 seconds in the process provided by the invention, the cooling speed of the compressed gas is proper, the technical index can be completely reached, and the problems that air cooling is not hard and cracks are generated by quenching liquid medium are solved. Meanwhile, the temperature of the quenched workpiece is high and is 250-300 ℃, so that the alloy cast iron camshaft can finish self-tempering during air cooling, low-temperature tempering procedures are reduced, product performance is improved, and production cost is saved.
The induction quenching process for hardening the alloy cast iron camshaft by using compressed air can not only prevent the alloy cast iron camshaft product from generating cracks in the quenching process, but also harden the alloy cast iron camshaft and enable the camshaft product to meet the technical requirements. The invention successfully solves the problems of cracks and unqualified hardness in the induction quenching process of the alloy cast iron camshaft in the prior art and equipment; the original equipment is simply modified, so that the method is practical and convenient, and the utilization rate of the equipment is improved; the quality of the alloy cast iron camshaft is guaranteed, waste products are eliminated, the low-temperature tempering process is reduced, the production cost is reduced, the economic benefit is obviously improved, and the production and circulation speed of products is accelerated.
Claims (4)
1. An induction hardening process for hardening an alloy cast iron camshaft using compressed air, the alloy cast iron having chemical composition (%): c, 3.10-3.25; mn 0.75-0.95; 2.20-2.40 of Si; p is less than or equal to 0.15; s is less than or equal to 0.20; 0.20-0.35 of Ni; 1.35-1.55 parts of Cr; 0.35-0.55 percent of Mo; the method is characterized by comprising the following steps:
s1, preheating: in the first stage, the camshaft is induction heated to 180-210 ℃ at the heating rate of 40-50 ℃/second, and then heating is suspended for 2-5 seconds; in the second stage, the camshaft is induction heated to 550-600 ℃ at the heating rate of 40-50 ℃/second, and then heating is suspended for 2-5 seconds; in the third stage, the camshaft is induction heated to 810-850 ℃ at the heating rate of 40-50 ℃/second, and then heating is suspended for 2-5 seconds;
s2, heating to a quenching temperature: induction heating the camshaft preheated in the step S1 to 900-940 ℃ at the heating rate of 40-50 ℃/second;
s3, quenching: quenching the camshaft heated in the step S2 by using compressed air with the pressure of 0.4-0.5MPa as a quenching medium, and cooling the camshaft to 250-300 ℃;
s4, residual temperature tempering: and (4) standing the camshaft quenched in the step S3 for 50-60 minutes at room temperature, and finishing the tempering process by using the residual temperature after quenching.
2. The induction hardening process using compressed air to quench alloy cast iron camshafts as claimed in claim 1, wherein: the first-stage heating temperature in the step S1 is preferably 190 +/-10 ℃; the heating temperature of the second stage is preferably 570 +/-10 ℃; the heating temperature in the third stage is preferably 830 +/-10 ℃.
3. The induction hardening process using compressed air to quench alloy cast iron camshafts as claimed in claim 1, wherein: the heating temperature in step S2 is preferably 920 ± 10 ℃.
4. The induction hardening process using compressed air to quench alloy cast iron camshafts as claimed in claim 1, wherein: the time for suspending heating in the three stages in step S1 is preferably 3 seconds.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911328950.6A CN110964898A (en) | 2019-12-20 | 2019-12-20 | Induction quenching process for hardening alloy cast iron camshaft by using compressed air |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911328950.6A CN110964898A (en) | 2019-12-20 | 2019-12-20 | Induction quenching process for hardening alloy cast iron camshaft by using compressed air |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110964898A true CN110964898A (en) | 2020-04-07 |
Family
ID=70035632
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911328950.6A Pending CN110964898A (en) | 2019-12-20 | 2019-12-20 | Induction quenching process for hardening alloy cast iron camshaft by using compressed air |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110964898A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111270049A (en) * | 2020-04-21 | 2020-06-12 | 河南柴油机重工有限责任公司 | High-frequency heat treatment protection method for thin-wall hole shaft parts |
| CN112080612A (en) * | 2020-08-10 | 2020-12-15 | 南京工业大学 | Metal piece surface residual stress optimization method and device based on electromagnetic induction heating and surface rapid cooling |
| CN113755743A (en) * | 2020-06-04 | 2021-12-07 | 南通华严磨片有限公司 | Sharp edge grinding disc |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102676785A (en) * | 2012-06-08 | 2012-09-19 | 荆州环球汽车零部件制造有限公司 | Induction hardening process capable of hardening hard-alloy cast iron camshaft |
| CN104959793A (en) * | 2015-06-29 | 2015-10-07 | 安庆市吉安汽车零件锻轧有限公司 | Camshaft argon arc remelting production and machining process |
| CN105714028A (en) * | 2014-12-05 | 2016-06-29 | 衡阳风顺车桥有限公司 | Method for reducing deforming and cracking of high-frequency quenching part |
-
2019
- 2019-12-20 CN CN201911328950.6A patent/CN110964898A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102676785A (en) * | 2012-06-08 | 2012-09-19 | 荆州环球汽车零部件制造有限公司 | Induction hardening process capable of hardening hard-alloy cast iron camshaft |
| CN105714028A (en) * | 2014-12-05 | 2016-06-29 | 衡阳风顺车桥有限公司 | Method for reducing deforming and cracking of high-frequency quenching part |
| CN104959793A (en) * | 2015-06-29 | 2015-10-07 | 安庆市吉安汽车零件锻轧有限公司 | Camshaft argon arc remelting production and machining process |
Non-Patent Citations (1)
| Title |
|---|
| 赵欣等: "感应淬火层内的裂纹分析", 《西华大学学报(自然科学版)》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111270049A (en) * | 2020-04-21 | 2020-06-12 | 河南柴油机重工有限责任公司 | High-frequency heat treatment protection method for thin-wall hole shaft parts |
| CN113755743A (en) * | 2020-06-04 | 2021-12-07 | 南通华严磨片有限公司 | Sharp edge grinding disc |
| CN113755743B (en) * | 2020-06-04 | 2022-05-13 | 南通华严磨片有限公司 | Sharp edge grinding disc |
| CN112080612A (en) * | 2020-08-10 | 2020-12-15 | 南京工业大学 | Metal piece surface residual stress optimization method and device based on electromagnetic induction heating and surface rapid cooling |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110964898A (en) | Induction quenching process for hardening alloy cast iron camshaft by using compressed air | |
| CN101476029B (en) | Heat treatment method for diesel engine cam | |
| CN103014283B (en) | Manufacture method of extremely-thick steel plate for hydropower station through continuous-cast billet | |
| CN104946870A (en) | Heat treatment method for strength of 28CrMoNiV steel capable of improving industrial steam turbine rotor forge piece | |
| CN101024870A (en) | Low-temperature high-strength, high-toughness steel and preparing method therefor | |
| CN102899460A (en) | Heat treatment method for martensitic stainless steel forging module | |
| CN104087742A (en) | Differential temperature heat treatment method for centrifugal compound high-chromium steel roller | |
| CN102925903B (en) | Heat treatment method for die-casting die | |
| CN103352108A (en) | H13 molten steel cold and hot treatment process | |
| CN111139345A (en) | Heat treatment method of steel | |
| CN113862434B (en) | Heat treatment process of 35CrNi3MoVR material for thick-wall ultrahigh-pressure container | |
| CN104561504A (en) | Heat treatment method for one-piece casting hot-rolled strip supporting roller | |
| CN102676785A (en) | Induction hardening process capable of hardening hard-alloy cast iron camshaft | |
| CN104593573A (en) | Combined thermomechanical treatment strengthening method for efficiently improving strength and toughness of non-quenched and tempered steel | |
| CN107099767A (en) | A kind of explosion drill bit Technology for Heating Processing | |
| CN102181613B (en) | Heat treatment method for large-scale Cr12Mov workpiece | |
| CN102758068A (en) | Heat treatment method of GCr15 steel | |
| CN101538643A (en) | Process for quenching H13 steel by high-pressure gas stepped quick cooling | |
| CN103993233A (en) | Novel high-service life die-casting mold steel and process method for manufacturing aluminum-magnesium die-casting mold | |
| WO2019223491A1 (en) | Method for manufacturing high-strength crankshaft | |
| CN102212664B (en) | Heat treatment method of stainless steel traction pin | |
| CN104762558A (en) | High-strength impact-resistance type steel used for shelf beam and welding technology thereof | |
| CN111676362B (en) | Novel quenching-partitioning-isothermal quenching heat treatment method capable of obtaining Si-series ultrahigh-strength disc spring | |
| CN111101077B (en) | Low-cost high-wear-resistance stretch reducing roller and heat treatment process thereof | |
| CN114150114A (en) | Improved heat treatment method for welded pipe die steel |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20200407 |
|
| RJ01 | Rejection of invention patent application after publication |