JPH0237406B2 - - Google Patents
Info
- Publication number
- JPH0237406B2 JPH0237406B2 JP57028477A JP2847782A JPH0237406B2 JP H0237406 B2 JPH0237406 B2 JP H0237406B2 JP 57028477 A JP57028477 A JP 57028477A JP 2847782 A JP2847782 A JP 2847782A JP H0237406 B2 JPH0237406 B2 JP H0237406B2
- Authority
- JP
- Japan
- Prior art keywords
- heating
- cooling
- temperature
- present
- induction hardening
- 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.)
- Expired - Lifetime
Links
- 238000010438 heat treatment Methods 0.000 claims description 33
- 238000001816 cooling Methods 0.000 claims description 27
- 230000006698 induction Effects 0.000 claims description 19
- 238000000034 method Methods 0.000 claims description 17
- 238000010791 quenching Methods 0.000 description 12
- 230000000171 quenching effect Effects 0.000 description 12
- 238000007796 conventional method Methods 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 238000005266 casting Methods 0.000 description 4
- 239000000498 cooling water Substances 0.000 description 4
- 238000003303 reheating Methods 0.000 description 4
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 229910001018 Cast iron Inorganic materials 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 229910001141 Ductile iron Inorganic materials 0.000 description 1
- 229910001060 Gray iron Inorganic materials 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005496 eutectics Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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
- C21D1/06—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
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
Description
【発明の詳細な説明】
本発明は、材質的に高周波焼入が比較的困難で
ある鋳物部品について、焼入時の加熱−冷却方式
を改良することによつて焼入可能とした高周波焼
入方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention provides induction hardening, which makes it possible to harden cast parts whose material is relatively difficult to induction harden by improving the heating-cooling method during hardening. It is about the method.
鋳物部品の高周波焼入に関しては、従来は焼入
かたさを得るため加熱速度をゆるやかにし加熱時
間も長くし、また放冷時間をも長く取つていた。
しかし、この従来方法では、放冷時間が長いため
焼入ひずみが生じ、また薄い硬化層を得にくいこ
とから、靭性の面でも問題となつていた。さらに
上記のように加熱時間が長くかつ放冷時間が長い
ことより、処理時間も他の高周波焼入に比べて長
い等の欠点があつた。 Regarding induction hardening of cast parts, conventionally, in order to obtain hardening hardness, the heating rate was slow and the heating time was long, and the cooling time was also long.
However, in this conventional method, quenching distortion occurs due to the long cooling time, and it is difficult to obtain a thin hardened layer, which also poses problems in terms of toughness. Furthermore, as mentioned above, since the heating time and cooling time are long, the processing time is also longer than other induction hardening methods.
本発明は上記問題を解決するためのもので、鋳
物部品において高周波焼入時の加熱放冷時間が長
いために生じていた焼入ひずみを低減させ、放冷
時間の縮少により熱影響が内部まで達することを
防ぎ、硬化層を薄くして強い靭性を確保し、また
高周波焼入の処理時間の大幅な縮少を図つた鋳物
部品の高周波焼入方法を提供することを目的とす
る。 The present invention is intended to solve the above-mentioned problems, and reduces the quenching distortion that occurs in cast parts due to the long heating and cooling time during induction hardening. The purpose of the present invention is to provide a method for induction hardening of cast parts, which prevents the hardening from reaching the maximum level, makes the hardened layer thinner, ensures strong toughness, and significantly reduces the processing time for induction hardening.
本発明は、鋳物部品を1050〜1100℃まで100〜
300℃／秒の加熱速度で加熱した後、800〜850℃
まで強制空冷し、ついで放冷による内部からの復
熱により850〜900℃とした後冷却することを特徴
とする鋳物部品の高周波焼入方法である。 The present invention allows casting parts to be heated to 1050 to 1100℃.
800-850℃ after heating at a heating rate of 300℃/second
This is an induction hardening method for cast parts, which is characterized by forced air cooling to a temperature of 850 to 900°C by recuperation from the inside by air cooling, and then cooling.
本発明方法において用いられる鋳物部品は、材
質的にはマトリツクス中の炭素量が一定でないた
め高周波焼入が比較的困難である材質のものなら
その種類は問わない。例えば、ねずみ鋳鉄、球状
黒鉛鋳鉄、合金鋳鉄等があげられる。 The cast parts used in the method of the present invention may be of any material as long as the amount of carbon in the matrix is not constant and induction hardening is relatively difficult. Examples include gray cast iron, spheroidal graphite cast iron, alloy cast iron, and the like.
本発明方法は、通常の高周波焼入機を用いて実
施される。高周波加熱は、まず鋳物部品を加熱用
コイル中に保持し、加熱用コイルに電流を流し、
鋳物部品の焼入部分表面に高周波電流によつて誘
導加熱して実施される。高周波加熱は、遊離炭素
の拡散が迅速になる温度すなわち鉄と炭素の共晶
点に達しない合理的な温度範囲1050〜1100℃まで
通常の加熱速度100〜300℃／秒で行う。 The method of the present invention is carried out using a conventional induction hardening machine. In high-frequency heating, first the cast part is held in a heating coil, and a current is passed through the heating coil.
It is carried out by induction heating the hardened surface of a cast part using a high-frequency current. High frequency heating is carried out at a normal heating rate of 100-300°C/sec to a reasonable temperature range of 1050-1100°C, at which the diffusion of free carbon is rapid, that is, the eutectic point of iron and carbon is not reached.
この加熱速度は、従来法が自然による放冷時間
の長いことを考慮して加熱速度をゆるやかに行う
必要があつたのに対し、本発明方法では強制空冷
を行うのにあわせて従来法より速めることができ
る。なお、加熱速度が100℃／秒より遅い場合熱
が内部まで達し、焼入ひずみが大きくなり、300
℃／秒より速い場合加熱時の熱応力による内部割
れの発生がおこることから、上記加熱速度で行う
のは合理的である。 This heating rate was required to be slow in the conventional method due to the long natural cooling time, but in the method of the present invention, it is faster than the conventional method in conjunction with forced air cooling. be able to. Note that if the heating rate is slower than 100°C/sec, the heat will reach the inside and the quenching strain will increase.
If the heating rate is faster than .degree. C./second, internal cracks will occur due to thermal stress during heating, so it is reasonable to carry out the heating at the above heating rate.
加熱後の冷却は、まず加熱処理表面にエアーを
送つて強制空冷を行い800〜850℃まで冷却し、そ
の後放冷による内部からの復熱で表面温度850〜
900℃まで放冷後、水焼入等の冷却を行つて焼入
をする。 For cooling after heating, air is first sent to the heated surface to perform forced air cooling to cool it to 800-850℃, and then the surface temperature is reduced to 850-850℃ by recuperating heat from the inside by air cooling.
After cooling to 900℃, it is hardened by cooling by water quenching etc.
ここで強制空冷して降下させる温度は、A3変
態点（720℃）より80〜130℃高い温度が後述の復
熱による温度上昇言いかえれば最適焼入温度の点
から好ましく、800℃より低い温度では復熱後の
温度が低く十分なかたさを得られない焼入温度で
あり、850℃より高い温度では復熱後の温度が高
く残留オーステナイトを生成する焼入温度である
ことから、上記温度範囲が合理的である。 Here, the temperature to be lowered by forced air cooling is preferably 80 to 130 degrees Celsius higher than the A3 transformation point (720 degrees Celsius) in terms of the temperature increase due to reheating, which will be described later. Regarding the temperature, the temperature after reheating is low and is the quenching temperature where sufficient hardness cannot be obtained, and the temperature higher than 850℃ is the quenching temperature where the temperature after reheating is high and residual austenite is generated. The range is reasonable.
また復熱によつて温度上昇させるのは、深サ方
向の温度の均一化からであり、最適焼入温度
（860〜880℃）を考慮して上記温度範囲が合理的
である。 Moreover, the temperature is increased by reheating to make the temperature uniform in the depth direction, and the above temperature range is reasonable considering the optimum quenching temperature (860 to 880°C).
以下、本発明の一実施例を図面に従つて説明す
る。 An embodiment of the present invention will be described below with reference to the drawings.
第１図は本発明方法の実施に使用される高周波
焼入装置の主要部分の断面図を示す。この装置を
用いて本発明方法を行うには、まず加熱用コイル
１の中心に合金鋳鉄からなる鋳物部品２を保持
し、前述の加熱用コイル１に周波数10KHzの高周
波電流を流すことにより鋳物部品２の焼入部分２
ａ（第１図中、斜線で示す。）を100〜300℃／秒の
加熱速度で主に加熱した。 FIG. 1 shows a sectional view of the main parts of an induction hardening apparatus used to carry out the method of the present invention. To carry out the method of the present invention using this device, first, a cast part 2 made of alloy cast iron is held in the center of the heating coil 1, and a high frequency current with a frequency of 10 KHz is passed through the heating coil 1, whereby the cast part is heated. Quenched part 2 of 2
a (indicated by diagonal lines in FIG. 1) was mainly heated at a heating rate of 100 to 300° C./sec.
所望加熱温度1050〜1100℃に加熱後、所要冷却
温度800〜850℃まで加熱用コイル１に設けた冷却
水及びエアー噴射孔３からエアーを鋳物部品２に
噴射して強制放冷した後すなわち放冷時間をとつ
て表面が所望焼入温度850〜900℃に達した後、冷
却水及びエアー噴射孔３から冷却水を噴射して鋳
物部品２を冷却し、高周波焼入を完了した。この
焼入処理によつて、焼入ひずみが少なく、硬化層
が薄くて強い靭性を有する鋳物部品を得た。 After heating to a desired heating temperature of 1050 to 1100°C, air is injected to the casting part 2 from the cooling water and air injection holes 3 provided in the heating coil 1 to a required cooling temperature of 800 to 850°C, and then the casting part 2 is forced to cool. After the surface reached the desired quenching temperature of 850 to 900° C. after a cooling period, cooling water was injected from the cooling water and air injection holes 3 to cool the cast part 2, and the induction hardening was completed. Through this quenching treatment, a cast part with little quenching strain, a thin hardened layer, and strong toughness was obtained.
第２図には、上記鋳物部品２に対して施される
従来法及び上記本発明方法の場合の高周波焼入時
の温度サイクルを、横軸を焼入処理時間（秒）、
縦軸を鋳物部品の焼入部分の表面温度（℃）とし
た関係で表わす。第２図より明らかなように、本
発明方法の場合の温度変化は、従来法の温度変化
に比べて所望加熱温度すなわち本発明方法では
1050〜1100℃及び従来例では900〜950℃まで加熱
した後の放冷時間が大幅に縮少されている。 FIG. 2 shows the temperature cycles during induction hardening in the conventional method and the method of the present invention applied to the cast part 2, with the horizontal axis representing the hardening treatment time (seconds) and
It is expressed in relation to the surface temperature (°C) of the hardened part of the cast part on the vertical axis. As is clear from FIG. 2, the temperature change in the method of the present invention is at the desired heating temperature, which is the temperature change in the method of the present invention, compared to the temperature change in the conventional method.
The cooling time after heating to 1050 to 1100°C (or 900 to 950°C in the conventional example) is significantly reduced.
以上説明したように本発明方法は、加熱後の放
冷時間を短くするために強制空冷を行い、ついで
放冷による復熱により一旦温度を上げた後、冷却
するので、従来、鋳物部品の放冷時間が長いため
生じていた焼入ひずみを低減し、そして熱影響が
内部まで達することを防ぎ硬化層を薄くすること
により強い靭性を確保でき、高周波焼入時の加熱
冷却時間を従来より大幅に縮少してその分サイク
ルアツプを達成できる。したがつて、本発明は、
鋳物部品の様にマトリツクス中の炭素量が一定で
ないため高周波焼入方法が比較的困難であつた製
品についての最適な高周波焼入方法といえる。 As explained above, in the method of the present invention, forced air cooling is performed in order to shorten the cooling time after heating, and then the temperature is raised once by heat recovery by the cooling, and then cooled. By reducing the quenching strain that occurs due to long cooling times, and by making the hardened layer thinner by preventing heat effects from reaching the inside, strong toughness can be ensured, and heating and cooling times during induction hardening are significantly longer than before. It is possible to achieve cycle up by that amount. Therefore, the present invention
This can be said to be the optimal induction hardening method for products such as cast parts, where the amount of carbon in the matrix is not constant and therefore induction hardening is relatively difficult.
第１図は高周波焼入装置を用いて実施される本
発明方法の一実施例を示す説明図、第２図は本発
明方法と従来法との鋳物部品に対する焼入時間と
鋳物部品の表面温度との関係を示すグラフであ
る。
図中、１……加熱用コイル、２……鋳物部品、
２ａ……焼入部分、３……冷却水及びエアー噴射
孔。
Fig. 1 is an explanatory diagram showing an example of the method of the present invention carried out using an induction hardening device, and Fig. 2 shows the quenching time and surface temperature of cast parts using the method of the present invention and the conventional method. It is a graph showing the relationship between In the figure, 1... Heating coil, 2... Casting parts,
2a...Quenched portion, 3...Cooling water and air injection holes.
Claims (1)
の加熱速度で加熱した後、800〜850℃まで強制空
冷し、ついで放冷による内部からの復熱により
850〜900℃とした後、冷却することを特徴とする
鋳物部品の高周波焼入方法。1. After heating the cast parts to 1050-1100℃ at a heating rate of 100-300℃/second, forced air cooling to 800-850℃, and then by recuperation from the inside by air cooling.
A method for induction hardening of cast parts, characterized by heating to 850-900°C and then cooling.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57028477A JPS58147515A (en) | 1982-02-24 | 1982-02-24 | Induction hardening method of casting parts |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57028477A JPS58147515A (en) | 1982-02-24 | 1982-02-24 | Induction hardening method of casting parts |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58147515A JPS58147515A (en) | 1983-09-02 |
| JPH0237406B2 true JPH0237406B2 (en) | 1990-08-24 |
Family
ID=12249721
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57028477A Granted JPS58147515A (en) | 1982-02-24 | 1982-02-24 | Induction hardening method of casting parts |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58147515A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61213320A (en) * | 1985-03-15 | 1986-09-22 | Daihatsu Motor Co Ltd | Induction hardening method for alloyed cast iron |
-
1982
- 1982-02-24 JP JP57028477A patent/JPS58147515A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58147515A (en) | 1983-09-02 |
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