CN114686648A - Forging heat treatment processing method - Google Patents
Forging heat treatment processing method Download PDFInfo
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- CN114686648A CN114686648A CN202210158872.5A CN202210158872A CN114686648A CN 114686648 A CN114686648 A CN 114686648A CN 202210158872 A CN202210158872 A CN 202210158872A CN 114686648 A CN114686648 A CN 114686648A
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- processing method
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- 238000010438 heat treatment Methods 0.000 title claims abstract description 51
- 238000005242 forging Methods 0.000 title claims abstract description 34
- 238000003672 processing method Methods 0.000 title claims abstract description 19
- 238000005422 blasting Methods 0.000 claims abstract description 69
- 238000001816 cooling Methods 0.000 claims abstract description 39
- 229910000734 martensite Inorganic materials 0.000 claims abstract description 23
- 238000000034 method Methods 0.000 claims abstract description 17
- 238000010791 quenching Methods 0.000 claims abstract description 14
- 230000000171 quenching effect Effects 0.000 claims abstract description 14
- 239000013078 crystal Substances 0.000 claims abstract description 13
- 229910001566 austenite Inorganic materials 0.000 claims abstract description 11
- 238000005496 tempering Methods 0.000 claims abstract description 11
- 230000001131 transforming effect Effects 0.000 claims abstract description 3
- 229910000831 Steel Inorganic materials 0.000 claims description 21
- 239000010959 steel Substances 0.000 claims description 21
- 239000002480 mineral oil Substances 0.000 claims description 5
- 235000010446 mineral oil Nutrition 0.000 claims description 5
- 238000004321 preservation Methods 0.000 claims description 3
- 239000002184 metal Substances 0.000 abstract description 3
- 238000002425 crystallisation Methods 0.000 abstract description 2
- 230000008025 crystallization Effects 0.000 abstract description 2
- 230000003647 oxidation Effects 0.000 abstract description 2
- 238000007254 oxidation reaction Methods 0.000 abstract description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 4
- 229910000954 Medium-carbon steel Inorganic materials 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 238000005480 shot peening Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 229910000746 Structural steel Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
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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
- 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
- C21D7/00—Modifying the physical properties of iron or steel by deformation
- C21D7/02—Modifying the physical properties of iron or steel by deformation by cold working
- C21D7/04—Modifying the physical properties of iron or steel by deformation by cold working of the surface
- C21D7/06—Modifying the physical properties of iron or steel by deformation by cold working of the surface by shot-peening or the like
-
- 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
- C21D2211/008—Martensite
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Forging (AREA)
Abstract
The invention discloses a heat treatment processing method for a forging, belongs to the technical field of metal heat treatment, and solves the problem that an existing blank oxidation layer of the forging prevents a blank from being cooled. Which comprises the following steps: forging; shot blasting: removing an oxide layer on the surface of the blank; quenching and heating: all crystal grains in the blank are converted into austenite; and (3) cooling: cooling the blank at a speed greater than the critical cooling speed to convert all austenite into martensite; high-temperature tempering; transforming the martensite into a tempered martensite; and air cooling. The method can remove oxide skin on the surface of the forging, promote the cooling crystallization of the forging, and ensure that austenite grains are completely converted into martensite grains.
Description
Technical Field
The invention relates to the technical field of metal heat treatment, in particular to a heat treatment processing method for a forge piece.
Background
At present, in the process of producing ferrous metal parts to be forged and formed, the forged blank of medium carbon steel and alloy steel needs to be subjected to quenching and tempering (quenching and high-temperature tempering), the conventional method is to directly heat the forged blank to austenitize internal crystal grains of the blank, and then, the blank is subjected to heat preservation and cooling (medium) to obtain a martensite structure required by quenching.
However, in the forging process, the high-temperature blank is directly exposed to the air during forging and forming, and an oxide layer is formed on the surface of the blank, wherein the thickness of the oxide layer reaches 0.1-0.5 mm. In the process of austenitizing the crystal grains of the quenching heating blank, the oxide layer is continuously oxidized and decarburized to form an isolation layer with a heat insulation effect, and in the quenching cooling process, the isolation layer can reduce the cooling speed of the surface of the blank so as to inhibit the formation of a quenched martensite structure of the blank, so that the depth and the percentage of the quenched martensite structure in the blank are not up to the standard. Can not meet the sampling requirement of quenching and tempering of medium carbon structural steel GB 13320-2007.
Disclosure of Invention
In view of the above, it is necessary to provide a method for heat treatment of a forging to solve the problem that the blank is prevented from cooling by the conventional blank oxidation layer of the forging.
The invention provides a heat treatment processing method of a forge piece, which comprises the following steps:
forging;
shot blasting: removing an oxide layer on the surface of the blank;
quenching and heating: all crystal grains in the blank are converted into austenite;
and (3) cooling: cooling the blank at a speed greater than the critical cooling speed to convert all austenite into martensite;
high-temperature tempering; transforming the martensite into a tempered martensite;
and (6) air cooling.
Furthermore, when in shot blasting, steel shots with the diameter of 0.2 mm-0.6 mm are adopted, the shot blasting speed of the impeller type shot blasting machine is 1400 r/min-1800 r/min, and the blank is shot blasted for 4 min-12 min.
Furthermore, steel shots with the diameter of 0.2mm, 0.3mm, 0.4mm, 0.5mm or 0.6mm are adopted during shot blasting, the shot blasting speed is 1600r/min, and the blank is shot blasted for 8 min.
Furthermore, during shot blasting, steel shots with the diameter of 0.4mm are adopted, the shot blasting speed is 1000r/min, 1200r/min, 1400r/min, 1600r/min or 1800r/min, and the blank is shot blasted for 8 min.
Furthermore, during shot blasting, steel shots with the diameter of 0.4mm are adopted, the shot blasting speed is 1600r/min, and the blank is subjected to shot blasting for 4min, 6min, 8min, 10min or 12 min.
Furthermore, the blank needs to be heated to 1150-1250 ℃ during forging, and the blank is forged and formed.
Further, in the forging process, a press is used for carrying out die forging forming on the blank to be processed, and the pressure range of the press is 500t-1000 t.
Further, in the quenching and heating process, the blank is heated to be more than 800 ℃, and the temperature is kept for 1 to 2 hours.
Further, in the cooling process, the blank is immersed in mineral oil at normal temperature for rapid cooling.
Further, in the high-temperature tempering process, the blank is heated to 500-650 ℃, and then is subjected to heat preservation for 1.5-2.5 h.
Compared with the prior art, the invention has the beneficial effects that:
according to the heat treatment processing method for the forge piece, the shot blasting process is added between the forging and the adjusting processing of the forge piece, oxide skin on the surface of the forge piece is removed, cooling crystallization of the forge piece is promoted, and austenite grains are completely converted into martensite grains.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:
FIG. 1 is a process flow diagram provided by the present invention;
FIG. 2 is a data chart of example 1 of the present invention;
FIG. 3 is a data chart of example 2 of the present invention;
FIG. 4 is a data chart of example 3 of the present invention;
Detailed Description
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the invention and together with the description, serve to explain the principles of the invention and not to limit the scope of the invention.
Embodiment 1, the heat treatment processing method for the forged piece in this embodiment includes the following steps;
forging, heating the medium carbon steel or alloy steel blank to 1150-1250 ℃ in a heating furnace, placing the blank in a forging die, and forging the forging die by a press machine at 500-1000 t so that the blank is forged and molded into a corresponding blank. In the specific implementation process, the press is generally used for 800t, and the regular blank is forged into a blank with a rough part shape.
Shot blasting: and conveying the forged blank to a shot blasting machine, wherein the shot blasting machine is an impeller type shot blasting machine, and shot blasting treatment is respectively carried out on the blank by the shot blasting machine by adopting steel shots with the thickness of 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm or 0.7mm, the shot blasting speed is 1600r/min, and shot blasting is carried out on the blank for 8 min.
Quenching and heating: and conveying the blank into a heating furnace, heating to over 800 ℃, preserving heat for 1-2 h, and converting all crystal grains in the blank into austenite.
And (3) cooling: and immersing the blank in mineral oil at normal temperature for rapid cooling, so that the crystal grains in the blank are converted into martensite.
High-temperature tempering: and (3) putting the blank into a heating furnace, heating to 500-650 ℃, preserving heat for 1.5-2.5 h, and converting martensite into tempered martensite.
Air cooling: and (4) placing the blank in the air, and naturally cooling the blank.
Finally, the obtained blank material is cut off from the middle, a sample is taken at a position 10cm deep from the surface of the blank piece, the sample is ground, polished and eroded, and the obtained sample is observed under a microscope of 100 times and compared with picture 3 in GB 13320-2007.
Embodiment 2, the heat treatment processing method for the forged piece in this embodiment includes the following steps;
forging, heating the medium carbon steel or alloy steel blank to 1150-1250 ℃ in a heating furnace, placing the blank in a forging die, and forging the forging die by a press machine at 500-1000 t so that the blank is forged and molded into a corresponding blank. In the specific implementation process, the press is generally used for 800t, and the regular blank is forged into a blank with a rough part shape.
Shot blasting: and conveying the forged blank to a shot blasting machine, wherein the shot blasting machine is an impeller type shot blasting machine, the shot blasting machine is used for carrying out shot blasting treatment on the blank by respectively adopting 0.4mm steel shots, the shot blasting speed is respectively 800r/min, 1000r/min, 1200r/min, 1400r/min, 1600r/min, 1800r/min or 2000r/min, and the blank is shot blasted for 8 min.
Quenching and heating: and conveying the blank into a heating furnace, heating to over 800 ℃, preserving heat for 1-2 h, and converting all crystal grains in the blank into austenite.
And (3) cooling: and immersing the blank in mineral oil at normal temperature for rapid cooling, so that the crystal grains in the blank are converted into martensite.
High-temperature tempering: and (3) putting the blank into a heating furnace, heating to 500-650 ℃, preserving heat for 1.5-2.5 h, and converting martensite into tempered martensite.
Air cooling: and (5) placing the blank in the air, and naturally cooling the blank.
Finally, the obtained blank material is cut off from the middle, a sample is taken at a position 10cm deep from the surface of the blank piece, the sample is ground, polished and eroded, and the obtained sample is observed under a microscope of 100 times and compared with picture 3 in GB 13320-2007.
Embodiment 3, the heat treatment processing method for a forging in this embodiment includes the following steps;
forging, heating the medium carbon steel or alloy steel blank to 1150-1250 ℃ in a heating furnace, placing the blank in a forging die, and forging the forging die by a press machine at 500-1000 t so that the blank is forged and molded into a corresponding blank. In the specific implementation process, the press is generally used for 800t, and the regular blank is forged into a blank with a rough part shape.
Shot blasting: and conveying the forged blank to a shot blasting machine, wherein the shot blasting machine is an impeller type shot blasting machine, and the shot blasting machine is used for carrying out shot blasting treatment on the blank by respectively adopting 0.4mm steel shots, the shot blasting speed is 1600r/min, and the blank is subjected to shot blasting for 2min, 4min, 6min, 8min, 10min, 12min or 14 min.
Quenching and heating: and conveying the blank into a heating furnace, heating to over 800 ℃, preserving heat for 1-2 h, and converting all crystal grains in the blank into austenite.
And (3) cooling: and immersing the blank in mineral oil at normal temperature for rapid cooling, so that the crystal grains in the blank are converted into martensite.
High-temperature tempering: and (3) putting the blank into a heating furnace, heating to 500-650 ℃, preserving heat for 1.5-2.5 h, and converting martensite into tempered martensite.
Air cooling: and (5) placing the blank in the air, and naturally cooling the blank.
Finally, the obtained blank material is cut off from the middle, a sample is taken at a position 10cm deep from the surface of the blank piece, the sample is ground, polished and eroded, the obtained sample is observed under a microscope with the power of 100 times, and the obtained sample is compared and analyzed with a comparison picture 3 in GB 13320-2007.
Referring to fig. 1 to 4, in practical experiments, after the green part without shot blasting to remove oxide layer is processed, the crystal grains of the sample wafer are consistent with the grade 5 of the e-diagram, the national standard requirement is grade 1-4, and the green part without shot blasting can not meet the national standard.
Referring to fig. 2, in example 1, the shot blasting speed is controlled to 1600r/min, the shot blasting time for the blank is 8min, steel shots with different diameters are used for shot blasting the blank part, and test data shows that when the diameter of the steel shot is less than 0.2mm, the intensity of shot blasting is insufficient, the oxide layer on the surface of the blank part is difficult to completely remove, and the blank part does not meet the national standard requirement. When the diameter of the steel shot is between 0.4mm and 0.5mm, the quality of the blank part is the best, and reaches a level of 2. However, when the diameter of the steel shot is increased, the quality of the blank part is reduced, and the excessive shot blasting causes a compact hardened layer to be formed on the surface of the blank, which also hinders the cooling of the blank, so that the grains in the blank cannot be transformed normally. When the steel shot exceeds 0.6mm, the internal quality of the blank part becomes 5 grades, and the requirements of national standards are not met any more.
Referring to fig. 3, in example 2, the size of the steel shot is 0.4mm, the shot blasting time for the blank is 8min, shot blasting is performed on the blank part by using steel shots with different diameters, and it can be known from experimental data that when the shot blasting speed is lower than 1000r/min, the intensity of shot blasting is insufficient, the oxide layer on the surface of the blank part is difficult to completely remove, so that the blank part cannot meet the national standard. When the shot blasting speed is about 1600r/min, the quality of the blank part is the best, and reaches the level of 2. However, as the peening speed is increased, the quality of the blank part is reduced, and excessive peening causes a dense hardened layer to be formed on the surface of the blank, which also hinders cooling of the blank, so that the grains inside the blank cannot be transformed normally. When the shot blasting speed exceeds 1800r/min, the internal quality of the blank part becomes 5 grades and does not conform to the national standard.
Referring to FIG. 4, in example 3, the size of the steel shot is 0.4mm, the shot blasting speed is 1600r/min, and the blank part is shot-blasted for different time periods. According to test data, when the shot blasting time is less than 2min, the intensity of shot blasting is insufficient, an oxide layer on the surface of the blank part is difficult to completely remove, the heat treatment of the blank part is influenced, and the blank part cannot meet the national standard requirement. When the shot blasting time is about 8min, the quality of the blank part is the best, and the level of 2 is reached. However, when the shot peening duration is increased, the quality of the blank part is reduced, and excessive shot peening causes a dense hardened layer to be formed on the surface of the blank, which also hinders the cooling of the blank, so that the grains inside the blank cannot be transformed normally. When the shot blasting time exceeds 12min, the internal quality of the blank part becomes 5 grades, and the requirements of national standards are not met any more.
In conclusion, the purposes of removing oxide scale and promoting blank cooling can be basically achieved by adopting steel shots with the diameter of 0.2-0.6 mm, the shot blasting speed of the impeller type shot blasting machine is 1400-1800 r/min, and the blank is shot-blasted for 4-12 min. Preferably, the best heat treatment effect is obtained when the diameter of the steel shot is 0.5mm, the shot blasting speed is 1600r/min and the shot blasting time is 8 min. However, the combination of conditions is also noted, and when the shot blasting is excessive, a dense hardened layer is formed on the surface of the blank, and the cooling of the blank is also hindered, so that the crystal grains in the blank cannot be normally transformed.
While the invention has been described with reference to specific preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.
Claims (10)
1. A forging heat treatment processing method is characterized by comprising the following steps:
forging;
shot blasting: removing an oxide layer on the surface of the blank;
quenching and heating: all crystal grains in the blank are converted into austenite;
and (3) cooling: cooling the blank at a speed greater than the critical cooling speed to convert all austenite into martensite;
high-temperature tempering; transforming the martensite into a tempered martensite;
and air cooling.
2. The heat treatment processing method for the forged piece, according to claim 1, is characterized in that during shot blasting, a steel shot with the diameter of 0.2 mm-0.6 mm is adopted, the shot blasting speed of the impeller type shot blasting machine is 1400 r/min-1800 r/min, and the blank is shot blasted for 4 min-12 min.
3. The heat treatment processing method for the forged piece, according to claim 2, is characterized in that steel shots with the diameter of 0.2mm, 0.3mm, 0.4mm, 0.5mm or 0.6mm are adopted during shot blasting, the shot blasting speed is 1600r/min, and the blank is shot blasted for 8 min.
4. The heat treatment processing method for the forged piece, according to claim 2, is characterized in that a steel shot with the diameter of 0.4mm is adopted during shot blasting, the shot blasting speed is 1000r/min, 1200r/min, 1400r/min, 1600r/min or 1800r/min, and the blank is shot blasted for 8 min.
5. The heat treatment processing method for the forged piece, according to claim 2, is characterized in that a steel shot with the diameter of 0.4mm is adopted during shot blasting, the shot blasting speed is 1600r/min, and the blank is shot-blasted for 4min, 6min, 8min, 10min or 12 min.
6. The heat treatment processing method for the forged piece according to claim 1, wherein the blank is heated to 1150-1250 ℃ during forging, and the blank is forged and formed.
7. The heat treatment processing method for the forged piece according to claim 1, wherein in the forging process, a press is used for carrying out die forging forming on the blank to be processed, and the pressure range of the press is 500t-1000 t.
8. The heat treatment processing method for the forged piece according to claim 1, wherein in the quenching and heating process, the blank is heated to above 800 ℃ and kept warm for 1-2 h.
9. The heat treatment processing method for the forged piece according to claim 1, wherein in the cooling process, the blank is immersed in mineral oil at normal temperature for rapid cooling.
10. The heat treatment processing method for the forged piece according to claim 1, wherein in the high-temperature tempering process, the blank is heated to 500-650 ℃ and then is subjected to heat preservation for 1.5-2.5 h.
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| CN202210158872.5A CN114686648A (en) | 2022-02-21 | 2022-02-21 | Forging heat treatment processing method |
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| CN202210158872.5A CN114686648A (en) | 2022-02-21 | 2022-02-21 | Forging heat treatment processing method |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1001043A1 (en) * | 1998-11-09 | 2000-05-17 | Daido Tokushuko Kabushiki Kaisha | Martensitic stainless steel parts and method for producing the same |
| CN101058886A (en) * | 2007-03-21 | 2007-10-24 | 中国重汽集团济南技术中心有限公司 | Surface treating and strengthening process for heavy vehicle bevel gear pair |
| CN104368755A (en) * | 2014-10-28 | 2015-02-25 | 盐城丰工机械有限公司 | Casting process of motor car driving arm |
| CN105331874A (en) * | 2015-09-26 | 2016-02-17 | 山东惠宇精密机械有限公司 | Spheroidal graphite cast iron cast gear and machining process thereof |
| CN109622706A (en) * | 2018-12-11 | 2019-04-16 | 吉林省正轩车架有限公司 | The process of auto parts is manufactured with middle thick boron alloyed steel plate heat stamping and shaping |
-
2022
- 2022-02-21 CN CN202210158872.5A patent/CN114686648A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1001043A1 (en) * | 1998-11-09 | 2000-05-17 | Daido Tokushuko Kabushiki Kaisha | Martensitic stainless steel parts and method for producing the same |
| CN101058886A (en) * | 2007-03-21 | 2007-10-24 | 中国重汽集团济南技术中心有限公司 | Surface treating and strengthening process for heavy vehicle bevel gear pair |
| CN104368755A (en) * | 2014-10-28 | 2015-02-25 | 盐城丰工机械有限公司 | Casting process of motor car driving arm |
| CN105331874A (en) * | 2015-09-26 | 2016-02-17 | 山东惠宇精密机械有限公司 | Spheroidal graphite cast iron cast gear and machining process thereof |
| CN109622706A (en) * | 2018-12-11 | 2019-04-16 | 吉林省正轩车架有限公司 | The process of auto parts is manufactured with middle thick boron alloyed steel plate heat stamping and shaping |
Non-Patent Citations (2)
| Title |
|---|
| 劳动人事部培训就业局: "锻工工艺学", 31 March 1988, 劳动人事出版社, pages: 80 - 81 * |
| 武振华;: "AF1410钢零件表面喷丸处理工艺的研究", 装备机械, no. 02, pages 134 - 135 * |
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