CN117123782B - Steam treatment process of iron-based powder metallurgy part - Google Patents

Steam treatment process of iron-based powder metallurgy part

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Publication number
CN117123782B
CN117123782B CN202311065951.2A CN202311065951A CN117123782B CN 117123782 B CN117123782 B CN 117123782B CN 202311065951 A CN202311065951 A CN 202311065951A CN 117123782 B CN117123782 B CN 117123782B
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steam treatment
steam
temperature
introducing
treatment process
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CN117123782A (en
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朱烨彪
包崇玺
陈志东
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Mbtm New Materials Group Co ltd
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Mbtm New Materials Group Co ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/10—Oxidising
    • C23C8/16—Oxidising using oxygen-containing compounds, e.g. water, carbon dioxide
    • C23C8/18—Oxidising of ferrous surfaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/24—After-treatment of workpieces or articles
    • B22F2003/241—Chemical after-treatment on the surface
    • B22F2003/242—Coating

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Powder Metallurgy (AREA)

Abstract

A steam treatment process for iron-based powder metallurgy parts comprises the steps of loading the parts to be treated into a steam treatment furnace, introducing nitrogen atmosphere for protection, heating to a low-temperature permeation temperature, preserving heat, introducing steam for steam treatment, vacuumizing at intervals in the heat preservation process, requiring that the relative atmospheric vacuum degree is lower than-10 kPa, introducing steam again for steam treatment, circulating times are more than or equal to 1 time, heating to the formation temperature of a steam treatment layer, preserving heat, vacuumizing at intervals in the heat preservation process, requiring that the relative atmospheric vacuum degree is lower than-10 kPa, introducing steam again for steam treatment, circulating times are more than or equal to 1 time, introducing nitrogen again after the steam treatment is finished, and taking out after cooling. The invention has simple process and easy operation, greatly improves the preparation efficiency of the steam treatment process on the premise of keeping the cost advantage, and the steam treatment layer on the surface of the treated part is compact and uniform, thereby effectively improving the wear resistance and the air tightness of the part.

Description

Steam treatment process of iron-based powder metallurgy part
Technical Field
The invention belongs to the technical field of surface protection of iron-based powder metallurgy parts, and relates to a steam treatment process of iron-based powder metallurgy parts.
Background
The requirements on wear resistance and air tightness of iron-based powder metallurgical parts are continuously improved by upgrading industries such as automobile engines, gear boxes and air-conditioning compressors, the existing steam treatment process is low in preparation efficiency, parts are easy to wear and air is leaked frequently, the requirements of the existing industry cannot be met, and the problem of how to improve the performance of the iron-based steam treatment parts under the low-cost condition is to be solved urgently at present.
The steam treatment process is a chemical reaction generated between superheated steam and an iron matrix, and is represented by the following formula:
3Fe+4H2O＝＝Fe3O4+4H2
Wherein, the generation of Fe 3O4 is a key factor affecting the hardness, wear resistance and air tightness of the iron-based powder metallurgy part, and the temperature, atmosphere (steam and hydrogen ratio) and charging amount can greatly influence the progress of the steam treatment process. It can be observed from the chemical equation that the consumption and generation ratio of the water vapor to the hydrogen is 1:1, and when the hydrogen in the steam treatment furnace is accumulated to a certain concentration, the reaction dynamics process is slowed down, so that the preparation efficiency is greatly influenced. The existing steam treatment process is to directly and continuously introduce steam into the furnace at a specific temperature for oxidation reaction, directly exhaust the gas in the furnace through a bypass, the ratio of the steam to the hydrogen in the furnace is not controllable, and the exhaust mode can not effectively exhaust the hydrogen in the furnace according to the actual production process, so that the steam treatment reaction rate can be gradually reduced along with the time. In addition, hydrogen cannot be smoothly discharged out of the furnace body, and defects in the steam treatment layer can be caused, so that the quality of the film layer is reduced.
Therefore, a new steam treatment process for iron-based powder metallurgy parts needs to be developed, and the requirements of high preparation effect, good wear resistance and good air tightness are met.
Disclosure of Invention
The invention aims to solve the technical problem of providing a steam treatment process of an iron-based powder metallurgy part, which is simple to operate and high in efficiency, wherein a steam treatment layer on the surface of the treated part is uniform and compact, and the wear resistance and the air tightness of the part are effectively improved.
The invention solves the technical problems by adopting the technical scheme that the steam treatment process of the iron-based powder metallurgy part is characterized by comprising the following steps of:
1) Filling the part to be treated into a steam treatment furnace, and introducing nitrogen atmosphere for protection;
2) Heating to low-temperature permeation temperature, preserving heat, introducing steam to perform steam treatment, vacuumizing at regular intervals in the heat preservation process, requiring the vacuum degree to be lower than-10 kPa relative to atmospheric pressure, and introducing steam again to perform steam treatment, wherein the cycle number is more than or equal to 1;
3) Then heating to the formation temperature of the steam treatment layer, preserving heat, vacuumizing at intervals in the heat preservation process, requiring the vacuum degree of the relative atmospheric pressure to be lower than-10 kPa, and introducing steam again for steam treatment, wherein the cycle number is more than or equal to 1;
4) And (5) introducing nitrogen again after the steam treatment is finished, and taking out after cooling.
Further, the low-temperature permeation temperature in the step 2) is 480-530 ℃.
Further, the formation temperature of the steam treatment layer in the step 3) is 530-600 ℃.
Further, depending on the usage requirements of the part, either step 2) or step 3) may be implemented separately.
Finally, the interval time of the vacuumizing treatment in the step 2) and the step 3) is 10-60 minutes.
Compared with the prior art, the invention has the advantages that:
(1) Compared with the existing steam treatment process, the steam treatment coating prepared by the steam treatment process has compact surface, uniform film thickness, higher compressive stress, lower friction coefficient (oil lubrication friction coefficient is about 0.11) and lower wear rate, can effectively improve the wear resistance and fatigue resistance of the steam treatment layer, and can prolong the service life of the parts;
(2) The steam treatment process can timely discharge generated hydrogen, so that the reaction is promoted to continuously proceed forward, and compared with the traditional steam treatment process, the steam treatment process has higher preparation efficiency and the quality of a steam treatment layer is improved in an omnibearing manner;
(3) The steam treatment process is simple to operate, equipment upgrading can be realized by simply modifying the existing equipment, the steam treatment process is suitable for mass production, and a standardized flow with strong execution performance can be formed;
The invention has simple process and easy operation, greatly improves the preparation efficiency of the steam treatment process on the premise of keeping the cost advantage, and the steam treatment layer on the surface of the treated part is compact and uniform, thereby effectively improving the wear resistance and the air tightness of the part.
Drawings
FIG. 1 is a flow chart of a steam treatment process provided by the present invention;
FIG. 2 is a surface topography of a steaming layer prepared in example 1 of the present invention;
FIG. 3 is a cross-sectional golden phase diagram of a vapor-treated layer prepared in example 1 of the present invention;
FIG. 4 is a chart showing XRD stress test results of the steam treated layer prepared in example 1 of the present invention;
FIG. 5 is a graph showing the friction coefficient of the steam treated layer prepared in example 1 of the present invention under oil lubrication conditions;
FIG. 6 shows the wear scar morphology of the steam treated layer prepared in example 1 of the present invention under oil lubrication conditions;
FIG. 7 is a cross-sectional golden phase diagram of a vapor-treated layer produced in example 2 of the present invention.
FIG. 8 is a surface topography of a steam treated layer prepared in comparative example 1 of the present invention;
FIG. 9 is a sectional golden phase diagram of a steam treated layer produced in comparative example 1 of the present invention;
FIG. 10 is a chart showing XRD stress test results of the steam treated layer prepared in comparative example 1 of the present invention;
FIG. 11 is a graph showing the friction coefficient of the steam treated layer prepared in comparative example 1 according to the present invention under oil lubrication conditions;
FIG. 12 is a wear scar morphology of the steam treated layer of comparative example 1 of the present invention under oil lubrication conditions;
FIG. 13 is a sectional golden phase diagram of a steam treated layer produced in comparative example 2 of the present invention.
Detailed Description
The invention is described in further detail below with reference to the embodiments of the drawings.
The steam treatment process flow of the present invention is shown in fig. 1.
Example 1:
(1) Charging the part to be treated, and introducing nitrogen atmosphere for protection;
(2) Heating to 500 ℃, preserving heat, introducing steam for steam treatment, carrying out vacuum treatment once every 30 minutes in the heat preservation process, requiring the vacuum degree of relative atmospheric pressure to be lower than-15 kPa, and introducing steam again for steam treatment, wherein the cycle number is 2 times, and the total time is half an hour;
(3) Heating to 560 ℃ again, preserving heat, carrying out vacuum treatment once every 30 minutes in the heat preservation process, requiring the vacuum degree of the relative atmospheric pressure to be lower than-15 kPa, and introducing water vapor again to carry out steam treatment, wherein the cycle times are 2 times, and the total time is half an hour;
(4) And (5) introducing nitrogen again after the steam treatment process is finished, and taking out after cooling.
The surface morphology of the steam treatment layer is shown in fig. 2, the section metallographic phase of the steam treatment layer is shown in fig. 3, the steam treatment layer shows 400-700 MPa compressive stress (fig. 4), the friction coefficient curve graph under the oil lubrication working condition (10N load, 50mm/s speed) is shown in fig. 5, the friction coefficient curve graph is about 0.11, and the abrasion mark morphology is shown in fig. 6.
Example 2:
(1) Charging the part to be treated, and introducing nitrogen atmosphere for protection;
(2) Heating to 520 ℃, preserving heat, introducing steam for steam treatment, carrying out vacuum treatment once every 20 minutes in the heat preservation process, requiring the vacuum degree of relative atmospheric pressure to be lower than-10 kPa, introducing steam again for steam treatment, and carrying out circulation times for 3 times for half an hour;
(3) After the temperature is raised to 590 ℃ again, vacuum treatment is carried out every 40 minutes in the heat preservation process, the vacuum degree of the relative atmospheric pressure is required to be lower than-10 kPa, steam is again introduced to carry out steam treatment, the cycle times are 2 times, and the total treatment time is two hours and 20 minutes;
(4) And (5) introducing nitrogen again after the steam treatment process is finished, and taking out after cooling.
The cross-sectional metallographic phase of the above-mentioned steaming layer is shown in FIG. 7.
Example 3:
(1) Charging the part to be treated, and introducing nitrogen atmosphere for protection;
(2) After the temperature is raised to 480 ℃, introducing steam to perform steam treatment, performing vacuum treatment once every 20 minutes in the heat preservation process, requiring the vacuum degree of relative atmospheric pressure to be lower than-10 kPa, introducing steam again to perform steam treatment, and performing circulation times for 2 times, wherein the total treatment time is 40 minutes;
(3) After the temperature is raised to 540 ℃ again, vacuum treatment is carried out every 30 minutes in the heat preservation process, the vacuum degree of the relative atmospheric pressure is required to be lower than-10 kPa, steam is again introduced to carry out steam treatment, the cycle times are 1 time, and the total treatment time is one hour;
(4) And (5) introducing nitrogen again after the steam treatment process is finished, and taking out after cooling.
Comparative example 1:
(1) Charging the part to be treated, and introducing nitrogen atmosphere for protection;
(2) Heating to 500 ℃, preserving heat, introducing steam for steam treatment, and treating for half an hour;
(3) Heating to 560 ℃ again, preserving heat, and treating for half an hour;
(4) And (5) introducing nitrogen again after the steam treatment process is finished, and taking out after cooling.
The surface morphology of the steam treatment layer is shown in fig. 8, the section metallographic phase of the steam treatment layer is shown in fig. 9, the steam treatment layer shows 300-500 MPa tensile stress (fig. 10), the friction coefficient curve graph under the oil lubrication working condition (10N load, 50mm/s speed) is shown in fig. 11, the friction coefficient curve graph is about 0.125, and the abrasion mark morphology is shown in fig. 12.
Comparative example 2:
(1) Charging the part to be treated, and introducing nitrogen atmosphere for protection;
(2) Heating to 520 ℃, preserving heat, introducing steam for steam treatment, and treating for half an hour;
(3) Heating to 590 ℃ again, preserving heat, and treating for three half hours;
(4) And (5) introducing nitrogen again after the steam treatment process is finished, and taking out after cooling.
The cross-sectional metallographic phase of the above-mentioned steaming layer is shown in FIG. 13.
From the experimental data of fig. 2 to 13, it can be seen that:
(1) The steam treatment coating prepared in the embodiment 1 of the invention has compact surface, uniform film thickness, high compressive stress, low friction coefficient (oil lubrication friction coefficient is about 0.11) and low wear rate. The steam treatment process can timely discharge generated hydrogen, so that the reaction is promoted to continuously proceed forward, and compared with the traditional steam treatment process, the steam treatment process has higher preparation efficiency and the quality of a steam treatment layer is improved in an omnibearing manner;
(2) As a result of comparative example 1 and comparative example 1, it was found that the conventional steam treatment process was low in preparation efficiency, had many pores on the surface, and exhibited a large tensile stress and poor abrasion resistance.
(3) As a result of comparative example 2 and comparative example 2, it was found that the novel steam treatment process can greatly shorten the steam treatment time and improve the production efficiency.
In conclusion, the steam treatment process has higher preparation efficiency, improves the preparation efficiency by more than 30 percent compared with the traditional process, ensures that the prepared steam treatment part has uniform surface layer and compact coating, can effectively improve the air tightness of the part, and further ensures that the prepared steam treatment layer shows larger compressive stress, thereby effectively improving the wear resistance and fatigue resistance of the steam treatment layer and prolonging the service life of the part. The steam treatment process is simple, equipment upgrading can be realized by simply modifying the existing equipment, and the method is suitable for mass production.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that it will be apparent to those skilled in the art that several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the scope of the invention.

Claims (3)

1.一种铁基粉末冶金零件的蒸汽处理工艺，其特征在于包括以下步骤：1. A steam treatment process for iron-based powder metallurgy parts, characterized by comprising the following steps: 1）将待处理的零件装入蒸汽处理炉，并通入氮气气氛保护；1) Load the parts to be treated into the steam treatment furnace and introduce nitrogen atmosphere for protection; 2）升温至低温渗透温度后保温，同时通入水蒸气进行蒸汽处理，在保温过程中每隔一定时间进行抽真空处理，要求相对大气压真空度低于-10 kPa，并再次通入水蒸气进行蒸汽处理，循环次数≥1次；2) After heating to the low-temperature infiltration temperature, keep the temperature and introduce water vapor for steam treatment. During the insulation process, vacuum treatment is carried out at regular intervals. The vacuum degree relative to atmospheric pressure is required to be lower than -10 kPa. Water vapor is introduced again for steam treatment. The number of cycles is ≥1; 所述低温渗透温度为480~530℃；The low-temperature infiltration temperature is 480-530°C; 3）接着升温到蒸汽处理层形成温度后保温，在保温过程中每隔一定时间进行抽真空处理，要求相对大气压真空度低于-10 kPa，并再次通入水蒸气进行蒸汽处理，循环次数≥1次；3) Then, the temperature is raised to the temperature at which the steam treatment layer is formed and then kept warm. During the warming process, vacuum treatment is performed at regular intervals, with the vacuum degree relative to atmospheric pressure being required to be lower than -10 kPa, and water vapor is introduced again for steam treatment. The number of cycles shall be ≥ 1; 所述蒸汽处理层形成温度为530~600℃；The steam treatment layer is formed at a temperature of 530-600°C; 4）蒸汽处理结束后再次通入氮气，待冷却取出。4) After the steam treatment is completed, introduce nitrogen again and take it out after cooling. 2.根据权利要求1所述的蒸汽处理工艺，其特征在于：所述步骤2）、步骤3）中的抽真空处理的间隔时间为10~60分钟。2. The steam treatment process according to claim 1, characterized in that the interval time of the vacuum treatment in step 2) and step 3) is 10 to 60 minutes. 3.根据权利要求1所述的蒸汽处理工艺，其特征在于：根据零件的使用要求，单独实施步骤2）或步骤3）。3. The steam treatment process according to claim 1, wherein step 2) or step 3) is performed separately according to the use requirements of the parts.
CN202311065951.2A 2023-08-23 2023-08-23 Steam treatment process of iron-based powder metallurgy part Active CN117123782B (en)

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CN1904322A (en) * 2006-08-05 2007-01-31 河南省西峡汽车水泵股份有限公司 Cast iron exhaust branch pipe having oxidized layer on surface and its surface oxidation method
CN212583901U (en) * 2020-07-06 2021-02-23 宁波市天瑞压缩机配件有限公司 Refrigerator compressor connecting rod and equipment for carrying out water vapor treatment on same

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JPH06287604A (en) * 1993-04-05 1994-10-11 Mitsubishi Materials Corp Manufacturing method of highly airtight sealed Fe-based sintered alloy parts
JP2006226561A (en) * 2005-02-15 2006-08-31 Muramatsu Fuusou Setsubi Kogyo Kk Heat treatment equipment
CN102828142B (en) * 2012-08-28 2014-05-21 东睦(江门)粉末冶金有限公司 Steam treatment method for piston products
CN113604772A (en) * 2021-08-18 2021-11-05 盛瑞传动股份有限公司 Workpiece steam treatment process

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1904322A (en) * 2006-08-05 2007-01-31 河南省西峡汽车水泵股份有限公司 Cast iron exhaust branch pipe having oxidized layer on surface and its surface oxidation method
CN212583901U (en) * 2020-07-06 2021-02-23 宁波市天瑞压缩机配件有限公司 Refrigerator compressor connecting rod and equipment for carrying out water vapor treatment on same

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