A chemical vapor deposition processing method for reducing product distortion

Abstract

The present application relates to a chemical vapor deposition processing method for reducing product deformation rate, steps comprising: rough machining processing, first quenching processing, a plurality of first tempering processing, finishing processing, chemical vapor deposition processing, second quenching processing and a plurality of second tempering processing for the parts in turn; wherein, the first quenching processing condition is same with the second quenching processing condition; the first tempering processing condition is same with the second tempering processing condition. The chemical vapor deposition processing method of the present application carries out the same quenching processing and tempering processing before and after the chemical vapor deposition processing for the parts, to avoid the deformation caused by microstructure difference; the chemical vapor deposition processing method of the present application also adjusts the heating rate, holding temperature, holding time, cooling rate and the like to make the parts uniformly distribute heat in the processing process, to improve the product deformation rate.

Description

Technical Field

[0001] This invention relates to the field of chemical vapor deposition technology, and more particularly to a chemical vapor deposition method for reducing product deformation rate. Background Technology

[0002] Chemical vapor deposition (CVD) coating is a coating technology with high hardness and good wear resistance, widely used in cutting tools, molds, and other fields. However, CVD treatment requires high temperatures, typically around 1000℃, exceeding the austenitic transformation temperature of most alloy tool and die steels. Therefore, during the coating process, tool and die steel parts re-enter the austenitic state, and the parts need to be cooled to lower temperatures after CVD, resulting in annealing. Their microstructure is usually in a pearlitic state, which cannot meet the mechanical performance requirements of mold products. Therefore, CVD-coated parts usually require re-heat treatment to obtain the desired mechanical properties. However, repeated heat treatment leads to significant heat treatment deformation, affecting the dimensional accuracy of the product. Generally, the deformation rate of tool and die steel parts after CVD coating and heat treatment is about 0.1%-0.2%, which cannot meet the precision requirements of high-precision products. Therefore, there is an urgent need for a technology that can effectively reduce heat treatment deformation of CVD-coated products to improve product accuracy. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies. The technical solution adopted by this invention is as follows:

[0004] The first aspect of the present invention is to provide a chemical vapor deposition method for reducing product deformation rate, the steps of which include:

[0005] The parts are subjected to rough machining, first quenching, several first tempering processes, finish machining, chemical vapor deposition, second quenching, and several second tempering processes in sequence; among which,

[0006] The conditions for the first quenching treatment are the same as those for the second quenching treatment;

[0007] The conditions for the first tempering process are the same as those for the second tempering process.

[0008] Preferably, the first quenching treatment or the first quenching treatment comprises the following sequential processes:

[0009] The process includes a first heating stage, a first holding stage, a second heating stage, a second holding stage, a third heating stage, a third holding stage, and a first cooling stage; among which,

[0010] The first heating stage to the third holding stage are carried out under vacuum conditions.

[0011] Preferably, the first heating stage involves heating to 480℃-540℃ at a heating rate of 11℃ / min-14℃ / min.

[0012] Preferably, the first holding stage is to hold at a temperature of 480°C-540°C for 30-40 minutes.

[0013] Preferably, the second heating stage involves heating to 780℃-840℃ at a heating rate of 11℃ / min-14℃ / min.

[0014] Preferably, the second holding stage is to hold at a temperature of 780°C-840°C for 30-40 minutes.

[0015] Preferably, the third heating stage involves heating to 1030℃-1050℃ at a heating rate of 7℃ / min-9℃ / min.

[0016] Preferably, the third holding stage is to hold at a temperature of 1030℃-1050℃ for 120min-150min.

[0017] Preferably, the first cooling stage involves cooling to 70℃-90℃ at a cooling rate of 30℃ / s-35℃ / s.

[0018] Preferably, the first tempering process or the second tempering process is performed 2-3 times.

[0019] Preferably, the first tempering process or the second tempering process comprises the following sequential steps:

[0020] The process includes a fourth heating stage, a fourth holding stage, a fifth heating stage, a fifth holding stage, and a second cooling stage; among which,

[0021] The fourth heating stage to the fifth holding stage are carried out under vacuum conditions.

[0022] Preferably, the fourth heating stage involves heating to 300℃-350℃ at a heating rate of 11℃ / min-14℃ / min.

[0023] Preferably, the fourth holding stage is to hold at a temperature of 300℃-350℃ for 30min-40min.

[0024] Preferably, the fifth heating stage involves heating to 530℃-550℃ at a heating rate of 11℃ / min-14℃ / min.

[0025] Preferably, the fifth holding stage is to hold at a temperature of 530℃-550℃ for 200min-240min.

[0026] Preferably, the second cooling stage involves cooling to room temperature at a cooling rate of 3°C / s-4°C / s.

[0027] Preferably, the chemical vapor deposition process comprises the following sequential steps:

[0028] The sixth heating stage, the sixth holding stage, the seventh heating stage, the seventh holding stage, the eighth heating stage, the eighth holding stage, and the third cooling stage.

[0029] Preferably, the eighth holding stage is held at a temperature of 990°C-1010°C.

[0030] Preferably, the third cooling stage is a natural cooling to 70℃-90℃.

[0031] Preferably, the total duration from the sixth heating stage to the third cooling stage is 18-20 hours.

[0032] A second aspect of the present invention is to provide a chemical vapor deposition coating product, which is prepared by the chemical vapor deposition process described above.

[0033] Preferably, the deformation rate of the chemical vapor deposition coating product is not higher than 1.8 × 10⁻⁶. -4 .

[0034] The present invention adopts the above technical solution and has the following technical effects compared with the prior art:

[0035] The chemical vapor deposition (CVD) method of the present invention performs the same quenching and tempering treatments on the parts before CVD as the quenching and tempering treatments performed after CVD, in order to avoid deformation caused by differences in microstructure. The CVD method of the present invention also improves the deformation rate of the parts by adjusting the heating rate, holding temperature, holding time, cooling rate, etc., so as to make the heat evenly distributed on the parts during the processing. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the chemical vapor deposition process in this invention. Detailed Implementation

[0037] The specific embodiments of the present invention will be described in detail below.

[0038] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0039] The word "comprising" or similar terms used in the specification and claims of this patent application mean that the objects preceding "comprising" include the objects listed after "comprising" or their equivalents, and do not exclude other objects.

[0040] The numerical values ​​mentioned in this invention include all values ​​increasing one unit at a time from low to high, assuming that there is at least a two-unit interval between any lower and higher value. For example, if it is said that a component quantity or a physical quantity is better from 1 to 100, 10 to 90, and 20 to 80, it means that values ​​such as 5 to 95, 14 to 76, 23 to 67, 32 to 58, and 41 to 49 are clearly listed in this specification; for values ​​less than 1, 0.0001, 0.001, 0.01, or 0.1 are considered to be a suitable unit. The foregoing examples are for illustrative purposes only; in practice, all combinations of values ​​between the lowest and highest listed values ​​are considered to be clearly listed in this specification in a similar manner.

[0041] Example 1

[0042] This embodiment provides a chemical vapor deposition method for reducing product deformation rate, the steps of which include:

[0043] S1. Provide a part, the part is cylindrical, the length of the part is 50mm, the outer diameter of the part is 31mm, the inner diameter of the part is 16mm, the material of the part is SKD61, and the inner working surface of the part needs to be treated by chemical vapor deposition.

[0044] S2. Roughly machine the parts to the appropriate dimensions, leaving an appropriate machining allowance;

[0045] S3. Transfer the part to an air pressure of 10. -3 In a vacuum quenching furnace, the temperature was increased to 500℃ at a heating rate of 12℃ / min and held for 30 min; then increased to 800℃ at a heating rate of 12℃ / min and held for 30 min; then increased to 1030℃ at a heating rate of 8℃ / min for austenitization and held for 120 min; and finally decreased to 80℃ at a cooling rate of 32℃ / s for gas quenching.

[0046] S4-1, Transfer the part to an air pressure of 10. -3 In a vacuum tempering furnace with a temperature of Pa, the temperature is increased to 320°C at a heating rate of 12°C / min and held for 30 min; then increased to 530°C at a heating rate of 12°C / min and held for 240 min; and finally cooled to room temperature at a cooling rate of 4°C / s.

[0047] S4-2, Repeat S4-1 once;

[0048] S5. Perform precision machining on the parts to the required dimensions;

[0049] S6. Transfer the part to a chemical vapor deposition furnace, heat to 500°C for a first preheating treatment; heat to 800°C for a second preheating treatment; heat to 1000°C for chemical vapor deposition; and allow to cool naturally to 80°C; wherein...

[0050] The total duration of S6 is 18-20 hours;

[0051] S7. Transfer the part to the vacuum quenching furnace, heat it to 500°C at a heating rate of 12°C / min, hold for 30 min; heat it to 800°C at a heating rate of 12°C / min, hold for 30 min; heat it to 1030°C at a heating rate of 8°C / min for austenitization, hold for 120 min; and cool it to 80°C at a cooling rate of 32°C / s for gas quenching.

[0052] S8-1. Transfer the part to the vacuum tempering furnace, heat it to 320°C at a heating rate of 12°C / min, hold for 30 min; heat it to 530°C at a heating rate of 12°C / min, hold for 240 min; and cool it to room temperature at a cooling rate of 4°C / s.

[0053] S8-2, Repeat S8-1 once.

[0054] Example 2

[0055] This embodiment provides a chemical vapor deposition method for reducing product deformation rate, the steps of which include:

[0056] S1. Provide a part, the part is cylindrical, the length of the part is 50mm, the outer diameter of the part is 31mm, the inner diameter of the part is 16mm, the material of the part is SKD61, and the inner working surface of the part needs to be treated by chemical vapor deposition.

[0057] S2. Roughly machine the parts to the appropriate dimensions, leaving an appropriate machining allowance;

[0058] S3. Transfer the part to an air pressure of 10. -3 In a vacuum quenching furnace, the temperature was increased to 500℃ at a heating rate of 12℃ / min and held for 30 min; then increased to 800℃ at a heating rate of 12℃ / min and held for 30 min; then increased to 1030℃ at a heating rate of 8℃ / min for austenitization and held for 120 min; and finally decreased to 80℃ at a cooling rate of 32℃ / s for gas quenching.

[0059] S4-1, Transfer the part to an air pressure of 10.-3 In a vacuum tempering furnace with a temperature of Pa, the temperature is increased to 320°C at a heating rate of 12°C / min and held for 30 min; then increased to 530°C at a heating rate of 12°C / min and held for 240 min; and finally cooled to room temperature at a cooling rate of 4°C / s.

[0060] S4-2, Repeat S4-1 twice;

[0061] S5. Perform precision machining on the parts to the required dimensions;

[0062] S6. Transfer the part to a chemical vapor deposition furnace, heat to 500°C for a first preheating treatment; heat to 800°C for a second preheating treatment; heat to 1000°C for chemical vapor deposition; and allow to cool naturally to 80°C; wherein...

[0063] The total duration of S6 is 18-20 hours;

[0064] S7. Transfer the part to the vacuum quenching furnace, heat it to 500°C at a heating rate of 12°C / min, hold for 30 min; heat it to 800°C at a heating rate of 12°C / min, hold for 30 min; heat it to 1030°C at a heating rate of 8°C / min for austenitization, hold for 120 min; and cool it to 80°C at a cooling rate of 32°C / s for gas quenching.

[0065] S8-1. Transfer the part to the vacuum tempering furnace, heat it to 320°C at a heating rate of 12°C / min, hold for 30 min; heat it to 530°C at a heating rate of 12°C / min, hold for 240 min; and cool it to room temperature at a cooling rate of 4°C / s.

[0066] S8-2, Repeat S8-1 twice.

[0067] Example 3

[0068] This embodiment provides a chemical vapor deposition method for reducing product deformation rate, the steps of which include:

[0069] S1. Provide a part, the part is cylindrical, the length of the part is 50mm, the outer diameter of the part is 31mm, the inner diameter of the part is 16mm, the material of the part is SKD61, and the inner working surface of the part needs to be treated by chemical vapor deposition.

[0070] S2. Roughly machine the parts to the appropriate dimensions, leaving an appropriate machining allowance;

[0071] S3. Transfer the part to an air pressure of 10. -3In a vacuum quenching furnace, the temperature was increased to 500℃ at a heating rate of 12℃ / min and held for 30 min; then increased to 800℃ at a heating rate of 12℃ / min and held for 30 min; then increased to 1030℃ at a heating rate of 8℃ / min for austenitization and held for 120 min; and finally decreased to 80℃ at a cooling rate of 32℃ / s for gas quenching.

[0072] S4-1, Transfer the part to an air pressure of 10. -3 In a vacuum tempering furnace with a temperature of Pa, the temperature is increased to 320°C at a heating rate of 12°C / min and held for 30 min; then increased to 550°C at a heating rate of 12°C / min and held for 240 min; and finally cooled to room temperature at a cooling rate of 4°C / s.

[0073] S4-2, Repeat S4-1 once;

[0074] S5. Perform precision machining on the parts to the required dimensions;

[0075] S6. Transfer the part to a chemical vapor deposition furnace, heat to 500°C for a first preheating treatment; heat to 800°C for a second preheating treatment; heat to 1000°C for chemical vapor deposition; and allow to cool naturally to 80°C; wherein...

[0076] The total duration of S6 is 18-20 hours;

[0077] S7. Transfer the part to the vacuum quenching furnace, heat it to 500°C at a heating rate of 12°C / min, hold for 30 min; heat it to 800°C at a heating rate of 12°C / min, hold for 30 min; heat it to 1030°C at a heating rate of 8°C / min for austenitization, hold for 120 min; and cool it to 80°C at a cooling rate of 32°C / s for gas quenching.

[0078] S8-1. Transfer the part to the vacuum tempering furnace, heat it to 320°C at a heating rate of 12°C / min, hold for 30 min; heat it to 550°C at a heating rate of 12°C / min, hold for 240 min; and cool it to room temperature at a cooling rate of 4°C / s.

[0079] S8-2, Repeat S8-1 once.

[0080] Example 4

[0081] This embodiment provides a chemical vapor deposition method for reducing product deformation rate, the steps of which include:

[0082] S1. Provide a part, the part is cylindrical, the length of the part is 50mm, the outer diameter of the part is 31mm, the inner diameter of the part is 16mm, the material of the part is SKD61, and the inner working surface of the part needs to be treated by chemical vapor deposition.

[0083] S2. Roughly machine the parts to the appropriate dimensions, leaving an appropriate machining allowance;

[0084] S3. Transfer the part to an air pressure of 10. -3 In a vacuum quenching furnace, the temperature was increased to 500℃ at a heating rate of 12℃ / min and held for 30 min; then increased to 800℃ at a heating rate of 12℃ / min and held for 30 min; then increased to 1050℃ at a heating rate of 8℃ / min for austenitization and held for 120 min; and finally decreased to 80℃ at a cooling rate of 32℃ / s for gas quenching.

[0085] S4-1, Transfer the part to an air pressure of 10. -3 In a vacuum tempering furnace with a temperature of Pa, the temperature is increased to 320°C at a heating rate of 12°C / min and held for 30 min; then increased to 530°C at a heating rate of 12°C / min and held for 240 min; and finally cooled to room temperature at a cooling rate of 4°C / s.

[0086] S4-2, Repeat S4-1 once;

[0087] S5. Perform precision machining on the parts to the required dimensions;

[0088] S6. Transfer the part to a chemical vapor deposition furnace, heat to 500°C for a first preheating treatment; heat to 800°C for a second preheating treatment; heat to 1000°C for chemical vapor deposition; and allow to cool naturally to 80°C; wherein...

[0089] The total duration of S6 is 18-20 hours;

[0090] S7. Transfer the part to the vacuum quenching furnace, heat it to 500°C at a heating rate of 12°C / min, hold for 30 min; heat it to 800°C at a heating rate of 12°C / min, hold for 30 min; heat it to 1050°C at a heating rate of 8°C / min for austenitization, hold for 120 min; and cool it to 80°C at a cooling rate of 32°C / s for gas quenching.

[0091] S8-1. Transfer the part to the vacuum tempering furnace, heat it to 320°C at a heating rate of 12°C / min, hold for 30 min; heat it to 530°C at a heating rate of 12°C / min, hold for 240 min; and cool it to room temperature at a cooling rate of 4°C / s.

[0092] S8-2, Repeat S8-1 once.

[0093] Detection Examples

[0094] This test example provides the rate of change in the pore size of chemical vapor deposition coating products prepared using the chemical vapor deposition treatment method described in Examples 1-X. The results are shown in the table below:

[0095]

[0096]

[0097] In summary, the chemical vapor deposition (CVD) method of the present invention performs the same quenching and tempering treatments on the parts before CVD as those performed after CVD, in order to avoid deformation caused by differences in microstructure. The CVD method of the present invention also improves the deformation rate of the parts by adjusting the heating rate, holding temperature, holding time, cooling rate, etc., so as to ensure uniform heat distribution on the parts during the processing.

[0098] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A chemical vapor deposition method for reducing product deformation rate, characterized in that the steps include... include: The parts are subjected to rough machining, first quenching, several first tempering processes, finish machining, chemical vapor deposition, second quenching, and several second tempering processes in sequence; among which, The conditions for the first quenching treatment are the same as those for the second quenching treatment, and the first quenching treatment or the second quenching treatment includes sequential processing: The process includes a first heating stage, a first holding stage, a second heating stage, a second holding stage, a third heating stage, a third holding stage, and a first cooling stage; among which, The first heating stage to the third holding stage are carried out under vacuum conditions; The first heating stage involves heating to 480℃-540℃ at a heating rate of 11℃ / min-14℃ / min. The first holding phase is to hold at a temperature of 480℃-540℃ for 30min-40min; The second heating stage involves heating to 780℃-840℃ at a heating rate of 11℃ / min-14℃ / min. The second holding stage is to hold at a temperature of 780℃-840℃ for 30-40 minutes; The third heating stage involves heating to 1030℃-1050℃ at a heating rate of 7℃ / min-9℃ / min. The third holding stage is to hold at a temperature of 1030℃-1050℃ for 120min-150min; The first cooling stage involves cooling down to 70℃-90℃ at a cooling rate of 30℃ / s-35℃ / s. The conditions for the first tempering process are the same as those for the second tempering process, and the first tempering process or the second tempering process includes the following sequential steps: The process includes a fourth heating stage, a fourth holding stage, a fifth heating stage, a fifth holding stage, and a second cooling stage; among which, The fourth heating stage to the fifth holding stage are carried out under vacuum conditions; The fourth heating stage involves heating to 300℃-350℃ at a heating rate of 11℃ / min-14℃ / min. The fourth holding stage is to hold at a temperature of 300℃-350℃ for 30min-40min; The fifth heating stage involves heating to 530℃-550℃ at a heating rate of 11℃ / min-14℃ / min. The fifth holding stage is to maintain a temperature of 530℃-550℃ for 200min-240min. The second cooling stage involves cooling down to room temperature at a rate of 3℃ / s-4℃ / s.

2. The chemical vapor deposition method according to claim 1, characterized in that, The first tempering process or the second tempering process is performed 2-3 times.

3. The chemical vapor deposition method according to claim 1, characterized in that, The chemical vapor deposition process includes the following sequential steps: The sixth heating stage, the sixth holding stage, the seventh heating stage, the seventh holding stage, the eighth heating stage, the eighth holding stage, and the third cooling stage.

4. The chemical vapor deposition method according to claim 3, characterized in that, The eighth holding stage is to hold at a temperature of 990℃-1010℃; The third cooling stage is a natural cooling to 70℃-90℃; The total duration from the sixth heating stage to the third cooling stage is 18-20 hours.

5. A chemical vapor deposition coating product, characterized in that, It is prepared by the chemical vapor deposition process as described in any one of claims 1-4.

6. The chemical vapor deposition coating product according to claim 5, characterized in that, The deformation rate of the chemical vapor deposition coating product is no higher than 1.8 × 10⁻⁶. -4 .

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