CN104164541A - Heat treatment method beneficial to core tenacity of auto screw - Google Patents

Heat treatment method beneficial to core tenacity of auto screw Download PDF

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Publication number
CN104164541A
CN104164541A CN201410402738.0A CN201410402738A CN104164541A CN 104164541 A CN104164541 A CN 104164541A CN 201410402738 A CN201410402738 A CN 201410402738A CN 104164541 A CN104164541 A CN 104164541A
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China
Prior art keywords
screw
automobile screw
automobile
cooling
quenching
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CN201410402738.0A
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Chinese (zh)
Inventor
吴光武
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Chengdu Hengtong Zhaoye Precision Machinery Co Ltd
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Chengdu Hengtong Zhaoye Precision Machinery Co Ltd
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Priority to CN201410402738.0A priority Critical patent/CN104164541A/en
Publication of CN104164541A publication Critical patent/CN104164541A/en
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Abstract

The invention discloses a heat treatment method beneficial to core tenacity of an auto screw. Heat treatment is carried out on the auto screw of which the material is 30# steel. The heat treatment method comprises a quenching step and a tempering step, wherein the quenching step comprises a warming procedure, a heat preservation procedure and a shock chilling procedure, which are sequentially carried out on the auto screw to be treated; the warming procedure is to heat the auto screw at normal temperature to 780-790 DEG C; the heat preservation procedure is to perform heat preservation on the auto screw for 8-10 minutes; the tempering step is to heat the auto screw obtained in a shock chilling manner to 500-520 DEG C and cool after heat preservation for no less than 4 hours; the heating rate for heating to 500-520 DEGC is not greater than 2 DEG C/s; and cooling is air cooling. The surface hardness of an existing 35# steel auto screw after heat treatment can be up to HRC27-30 by the heat treatment, the core tenacity is good, meanwhile, the texture and hardness uniformity is good, and the ratio of a heat treatment crack is smaller than 1%.

Description

A kind of heat treating method that is conducive to automobile screw center toughness
Technical field
The present invention relates to screw thermal treatment process field, particularly relate to a kind of heat treating method that is conducive to automobile screw center toughness.
Background technology
Screw is web member indispensable in automotive industry, is widely used the screw that a kind of physical dimension is standardized component on automobile, and its material is 35# steel, and hardness requirement value is HRC24-29, uses maximum M6 of being of a size of, M8 and M10.
Owing to applying on automobile with screwing, its quality directly affects by bus personnel's life safety, and in process of production, its specification of quality is very high, and specification of quality wherein mainly comprises to be organized uniformity of hardness, whether have crackle etc.In prior art, applying to thermal treatment process with screwing is generally and adopts 820-840 ℃ of insulation to be no less than quenching in 10 minutes, then carry out 500-550 ℃ of insulation and be no less than 4h tempering, yet the product that existing thermal treatment process obtains occurs that the possibility of cracking defect is larger, while is due to the limitation of size of screw itself, occur that undetected possibility is also larger, so a set of solid thermal treatment process is the key that guarantees automobile screw quality.
Summary of the invention
The possibility that occurs cracking defect for the product that in above-mentioned prior art, existing thermal treatment process obtains is larger, a set of solid thermal treatment process is the crucial problem that guarantees automobile screw quality, the invention provides a kind of heat treating method that is conducive to automobile screw center toughness.
For the problems referred to above, a kind of heat treating method that is conducive to automobile screw center toughness provided by the invention reaches goal of the invention by following technical essential: a kind of heat treating method that is conducive to automobile screw center toughness, for the automobile screw that is 30# steel to material, heat-treat, comprise quench in sequence step and tempering step, described quenching step comprises the heating process that pending automobile screw is carried out successively, insulation operation and quenching operation, described heating process is for to be heated to 780-790 ℃ by the automobile screw of normal temperature, and automobile screw temperature rests on 650 ℃ to the sands are running out between upper temperature limit in 15min, and temperature-rise period temperature rise rate is not more than 2 ℃/s,
Described insulation operation will be for being incubated 8-10min with the screw of getting on the car;
Described cooling process is cooling for adopting salt solution to carry out quenching to automobile screw;
Described tempering step is no less than after 4h coolingly for the cooling automobile screw obtaining of quenching being heated to 500-520 ℃ of insulation, and be heated to above the heat temperature raising speed of 500-520 ℃ and be not more than 2 ℃/s, described in be cooled to air cooling.
In above operation, being limited with of temperature rise rate in heating process is beneficial to the severe degree that slows down the accumulation of automobile screw built-in thermal stress, automobile screw temperature is beneficial to the thickness that reduces screw Decarburized layer in being limited with of more than 650 ℃ time, be beneficial to the oeverall quality of automobile screw, to the restriction of soaking time and heat-eliminating medium, make screw there is good tissue, uniformity of hardness.
In above drawing process, pass through the control to tempering step temperature rise rate, be conducive to prevent that tempering from adding the generation of thermal crack, the selection of tempering temperature is conducive to prevent, in automobile screw, recrystallize occurs, and the parameter of tempering temperature, time and the type of cooling selects to make the centre hardness of automobile screw to remain on HB150 left and right.
Further technical scheme is:
For further optimizing quenching quality, be lifted at the cleaning capacity that in quench process, cooling fluid changes into automobile screw Surface Oxygen, described salt solution is that concentration is the sodium chloride solution of 7-10%.
For further optimizing quenching quality, make the various piece of each screw in automobile screw is produced by batch all can obtain uniform speed of cooling, improve the surface cleaning quality of automobile screw in quenching operation, in quenching step, go back agitating procedure, described agitating procedure is synchronizeed and is carried out with cooling process, agitating procedure, for stirring at least one in automobile screw and salt solution, makes automobile screw and salt solution generation relative movement in cooling process.
For elimination or weakening, the impact of the internal stress of enrichment in quenching step on tempering step, also comprises ageing treatment step between described quenching step and tempering step.
For protection automobile screw surface quality, be beneficial to the bright and clean degree of screw thread working face, described cold sky is cooling in protective gas.
The present invention has following beneficial effect:
1, this operational path is simple, being limited with of temperature rise rate in heating process is beneficial to the severe degree that slows down the accumulation of automobile screw built-in thermal stress, automobile screw temperature is beneficial to the thickness that reduces screw Decarburized layer in being limited with of more than 650 ℃ time, be beneficial to the oeverall quality of automobile screw, to the restriction of soaking time and heat-eliminating medium, make screw there is good tissue, uniformity of hardness.The restriction of above thermal treatment process route and processing parameter, makes existing 35# steel automobile screw can reach HRC27-30 through Overheating Treatment rear surface hardness, and microstructure and hardness good uniformity, occurs that the ratio of heat treatment crack is less than 1% simultaneously.
2, in above drawing process, pass through the control to tempering step temperature rise rate, be conducive to prevent that tempering from adding the generation of thermal crack, the selection of tempering temperature is conducive to prevent, in automobile screw, recrystallize occurs, the parameter of tempering temperature, time and the type of cooling selects to make the centre hardness of automobile screw to remain on HB150 left and right, the toughness that is conducive to the product that this technique obtains, the shock resistance that is beneficial to product, is beneficial to product life.
Embodiment
Below in conjunction with embodiment, the present invention is described in further detail, but structure of the present invention is not limited only to following examples.
Embodiment 1:
A kind of heat treating method that is conducive to automobile screw center toughness, for the automobile screw that is 30# steel to material, heat-treat, comprise quench in sequence step and tempering step, described quenching step comprises heating process, insulation operation and the quenching operation that pending automobile screw is carried out successively, described heating process is for to be heated to 780-790 ℃ by the automobile screw of normal temperature, and automobile screw temperature rests on 650 ℃ to the sands are running out between upper temperature limit in 15min, and temperature-rise period temperature rise rate is not more than 2 ℃/s;
Described insulation operation will be for being incubated 8-10min with the screw of getting on the car;
Described cooling process is cooling for adopting salt solution to carry out quenching to automobile screw;
Described tempering step is no less than after 4h coolingly for the cooling automobile screw obtaining of quenching being heated to 500-520 ℃ of insulation, and be heated to above the heat temperature raising speed of 500-520 ℃ and be not more than 2 ℃/s, described in be cooled to air cooling.
In above operation, being limited with of temperature rise rate in heating process is beneficial to the severe degree that slows down the accumulation of automobile screw built-in thermal stress, automobile screw temperature is beneficial to the thickness that reduces screw Decarburized layer in being limited with of more than 650 ℃ time, be beneficial to the oeverall quality of automobile screw, to the restriction of soaking time and heat-eliminating medium, make screw there is good tissue, uniformity of hardness.
In above drawing process, pass through the control to tempering step temperature rise rate, be conducive to prevent that tempering from adding the generation of thermal crack, the selection of tempering temperature is conducive to prevent, in automobile screw, recrystallize occurs, and the parameter of tempering temperature, time and the type of cooling selects to make the centre hardness of automobile screw to remain on HB150 left and right.
Embodiment 2:
The present embodiment is further qualified on the basis of embodiment 1: for further optimizing quenching quality, be lifted at the cleaning capacity that in quench process, cooling fluid changes into automobile screw Surface Oxygen, described salt solution is that concentration is the sodium chloride solution of 7-10%.
For further optimizing quenching quality, make the various piece of each screw in automobile screw is produced by batch all can obtain uniform speed of cooling, improve the surface cleaning quality of automobile screw in quenching operation, in quenching step, go back agitating procedure, described agitating procedure is synchronizeed and is carried out with cooling process, agitating procedure, for stirring at least one in automobile screw and salt solution, makes automobile screw and salt solution generation relative movement in cooling process.
For elimination or weakening, the impact of the internal stress of enrichment in quenching step on tempering step, also comprises ageing treatment step between described quenching step and tempering step.
For protection automobile screw surface quality, be beneficial to the bright and clean degree of screw thread working face, described cold sky is cooling in protective gas.
Above content is the further description of the present invention being done in conjunction with concrete preferred implementation, can not assert that the specific embodiment of the present invention is confined to these explanations.For general technical staff of the technical field of the invention, not departing from other embodiments that draw under technical scheme of the present invention, all should be included in protection scope of the present invention.

Claims (5)

1. a heat treating method that is conducive to automobile screw center toughness, for the automobile screw that is 30# steel to material, heat-treat, comprise quench in sequence step and tempering step, it is characterized in that, described quenching step comprises heating process, insulation operation and the quenching operation that pending automobile screw is carried out successively, described heating process is for to be heated to 780-790 ℃ by the automobile screw of normal temperature, and automobile screw temperature rests on 650 ℃ to the sands are running out between upper temperature limit in 15min, and temperature-rise period temperature rise rate is not more than 2 ℃/s;
Described insulation operation will be for being incubated 8-10min with the screw of getting on the car;
Described cooling process is cooling for adopting salt solution to carry out quenching to automobile screw;
Described tempering step is no less than after 4h coolingly for the cooling automobile screw obtaining of quenching being heated to 500-520 ℃ of insulation, and be heated to above the heat temperature raising speed of 500-520 ℃ and be not more than 2 ℃/s, described in be cooled to air cooling.
2. a kind of heat treating method that is conducive to automobile screw center toughness according to claim 1, is characterized in that, described salt solution is that concentration is the sodium chloride solution of 7-10%.
3. a kind of heat treating method that is conducive to automobile screw center toughness according to claim 1, it is characterized in that, in quenching step, go back agitating procedure, described agitating procedure is synchronizeed and is carried out with cooling process, agitating procedure, for stirring at least one in automobile screw and salt solution, makes automobile screw and salt solution generation relative movement in cooling process.
4. a kind of heat treating method that is conducive to automobile screw center toughness according to claim 1, is characterized in that, between described quenching step and tempering step, also comprises ageing treatment step.
5. a kind of heat treating method that is conducive to automobile screw center toughness according to claim 1, is characterized in that, described cold sky is cooling in protective gas.
CN201410402738.0A 2014-08-17 2014-08-17 Heat treatment method beneficial to core tenacity of auto screw Pending CN104164541A (en)

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Application Number Priority Date Filing Date Title
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107586935A (en) * 2017-10-30 2018-01-16 四川圣亚凯紧固器材有限公司 The heat treatment method of screw
CN108723702A (en) * 2018-04-04 2018-11-02 海宁市丁桥镇永畅知识产权服务部 The manufacture craft of screw

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102051453A (en) * 2010-12-29 2011-05-11 西安航天精密机电研究所 Method for quenching small-size No. 45 steel parts
JP2012149304A (en) * 2011-01-19 2012-08-09 Nsk Ltd Heat treatment method of track member
CN102644647A (en) * 2012-04-23 2012-08-22 徐尚仁 Martensite stainless steel anti-theft screw manufactured by quenching hardness-increasing and brittle non-increasing process

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102051453A (en) * 2010-12-29 2011-05-11 西安航天精密机电研究所 Method for quenching small-size No. 45 steel parts
JP2012149304A (en) * 2011-01-19 2012-08-09 Nsk Ltd Heat treatment method of track member
CN102644647A (en) * 2012-04-23 2012-08-22 徐尚仁 Martensite stainless steel anti-theft screw manufactured by quenching hardness-increasing and brittle non-increasing process

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
《现代制造工程》 *
李安铭等: "45钢亚温淬火工艺的研究", 《金属热处理》 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107586935A (en) * 2017-10-30 2018-01-16 四川圣亚凯紧固器材有限公司 The heat treatment method of screw
CN108723702A (en) * 2018-04-04 2018-11-02 海宁市丁桥镇永畅知识产权服务部 The manufacture craft of screw

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Application publication date: 20141126