JPS6411687B2 - - Google Patents
Info
- Publication number
- JPS6411687B2 JPS6411687B2 JP56186618A JP18661881A JPS6411687B2 JP S6411687 B2 JPS6411687 B2 JP S6411687B2 JP 56186618 A JP56186618 A JP 56186618A JP 18661881 A JP18661881 A JP 18661881A JP S6411687 B2 JPS6411687 B2 JP S6411687B2
- Authority
- JP
- Japan
- Prior art keywords
- quenching
- rolled material
- temperature
- induction heating
- frequency induction
- 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
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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
- C21D1/34—Methods of heating
- C21D1/42—Induction heating
-
- 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
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- 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)
- Control Of Heat Treatment Processes (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Description
この発明は、熱間圧延ライン上で圧延材の焼入
を行なう直接焼入方法に関する。
通常、熱間圧延材の焼入装置は圧延ライン外に
設置されており、仕上圧延後の圧延材はローラー
コンベヤテーブル等によつて焼入設備まで搬送さ
れ、ここで搬送中自然放冷した圧延材を所定の焼
入温度（830〜900℃）まで再加熱した後、焼入さ
れる。
これに対し、直接焼入は焼入装置を熱間圧延ラ
インの仕上圧延機出側に設置し、仕上圧延機を通
過した直後の800〜920℃の高温を保持する圧延材
をオンラインで直ちに焼入装置に装入し、焼入を
行なうもので、前記通常の焼入における圧延材の
搬送、再加熱工程等を省略することができ、従つ
て再加熱用熱処理炉等の設備費や再加熱に要する
燃料費もかからず生産コストを大巾に低減できる
等の優れた利点を有する。
しかしながら従来、直接焼入によつて焼入した
圧延材はその長手方向トツプ、ボトム間における
機械的性質が均一とならず、バラツキを生じる欠
点があつた。
第１図は従来方法による直接焼入を行なつた60
キロ級高張力鋼板（20mm厚×20000mm長）の引張
強度を調査し、トツプ、ボトム間の強度差をグラ
フで表わしたものであるが、図に示すように３〜
４Kg／mm程度までの強度差を生じているものが多
いことがわかる。
このように従来直接焼入を行なつた圧延材がト
ツプ、ボトム間で機械的性質に差異を生じる原因
は焼入開始時点での圧延材の表面温度の差異によ
るものと考えられる。
すなわち、圧延機で圧延された圧延材とりわけ
薄肉圧延材は同一ラインに設置した焼入装置で連
続的に焼入れてゆくと、同一圧延材内のトツプ側
とボトム側とで焼入温度が異なる結果となるから
である。
第１表は、本発明者が条件の異なる圧延材
ABCについて、直接焼入開始時点でのトツプと
ボトムの温度差を調査した結果であるが、いずれ
の場合でも相当の温度差を生じていることが判明
した。
The present invention relates to a direct quenching method for quenching a rolled material on a hot rolling line. Usually, the quenching equipment for hot-rolled materials is installed outside the rolling line, and the rolled materials after finish rolling are transported to the quenching equipment by a roller conveyor table, etc., where they are cooled naturally during transportation. After the material is reheated to a predetermined quenching temperature (830-900°C), it is quenched. On the other hand, in direct quenching, the quenching equipment is installed on the exit side of the finishing mill of the hot rolling line, and the rolled material, which maintains a high temperature of 800 to 920°C immediately after passing through the finishing mill, is immediately quenched online. It is loaded into the charging equipment and hardened, and the transportation of the rolled material and the reheating process in the normal hardening can be omitted, and therefore the cost of equipment such as a heat treatment furnace for reheating and reheating can be omitted. It has excellent advantages such as the fact that it does not require much fuel and can significantly reduce production costs. However, conventionally, rolled materials quenched by direct quenching have had the disadvantage that mechanical properties are not uniform between the top and bottom in the longitudinal direction, resulting in variations. Figure 1 shows the result of direct quenching using the conventional method60
The tensile strength of a kilo-class high-tensile steel plate (20 mm thick x 20,000 mm long) was investigated, and the difference in strength between the top and bottom is shown in a graph.
It can be seen that there are many cases where the strength difference is up to about 4 kg/mm. The reason for the difference in mechanical properties between the top and bottom of a rolled material that has been conventionally directly quenched is thought to be due to the difference in surface temperature of the rolled material at the start of quenching. In other words, when a rolled material, especially a thin-walled rolled material, is continuously quenched in a quenching device installed on the same line, the quenching temperature will differ between the top and bottom sides of the same rolled material. This is because. Table 1 shows the inventor's rolling materials under different conditions.
The results of investigating the temperature difference between the top and bottom of ABC at the start of direct quenching revealed that there was a considerable temperature difference in both cases.
【表】
また、第２図は圧延材（25mm厚×20m長）の直
接焼入開始時点での表面温度をトツプからボトム
まで連続的に測定した結果であるが、図に見る如
く圧延材の表面温度はトツプ側ほど高く、ボトム
側ほど放冷によつて次第に低下している。
斯かる状況に鑑み、本発明者はこの種直接焼入
において焼入装置の入側直前に急速加熱の可能な
高周波誘導加熱装置を設けて前記第２図に見るよ
うな圧延材ボトム側の温度降下を補償することを
考え、種々実験、研究の結果、本発明を完成し
た。
すなわち本発明は、仕上圧延機の出側に焼入装
置を設け、熱間圧延ラインで圧延材の焼入を行な
う直接焼入において、上記焼入装置の入側の前に
高周波誘導加熱装置を設けるとともに、仕上圧延
機を出て高周波誘導加熱装置に入る前の段階で圧
延材の温度を測定し、該測定温度を演算器に入力
し、演算器に接続した加熱制御装置により焼入
時、圧延材のトツプからボトムまで一定の焼入温
度となるよう前記高周波誘導加熱装置の高周波電
流を制御する熱間圧延材の直接焼入方法を要旨と
する。
以下、掲げた図面に基づき本発明の構成を説明
する。
第３図は従来の直接焼入を説明する図で、熱間
圧延ラインの最終部分を示し、図中１はランアウ
ト・テーブル、２は仕上圧延機、３はレベラー、
４は直接焼入装置、５は圧延材である。
仕上圧延機２にて所望厚まで圧延された圧延材
５は、ランアウト・テーブル１上をレベラー３へ
と移送され、ここで平坦に矯正された後、ランア
ウト・テーブル１によつて直接焼入装置４へ送り
込まれる。
直接焼入装置４は第４図に示す如く、圧延材５
の走行ラインを挾んで上下に対峙するフレーム
６，６′と該フレーム６，６′を支承する門型架台
７よりなり、上部側フレーム６が門型架台７に設
けたボールジヤツキ８，８の昇降機構により上下
に昇降可能であつて、圧延材５の厚さの変化に対
応できるようになつている。
上下のフレーム６，６′には圧延材５の入側
（矢印）にピンチロール９，９′が設けてあり、該
ピンチロール９，９′に続いて圧延材５の出側に
かけて冷却剤噴出ノズル１０…と圧延材の押えロ
ール１１…とが交互に取付けられている。
矢印方向から上下フレーム６，６′間に送り込
まれた圧延材５は、入側から出側まで走行を停止
することなく連続的に移動し、その間に上記ノズ
ル１０…から噴射される冷却剤によつて焼入れさ
れて装置４から送り出される。
本発明方法は、第５図のブロツク図に示すよう
に直接焼入装置４の直前に高周波誘導加熱装置１
２を設け、該高周波誘導加熱装置１２と仕上圧延
機２との間の所定位置（図示例ではレベラー３の
後方）に圧延材５の表面温度を検出する温度セン
サー１３を設ける。
さらに、演算器１４、上記高周波誘導加熱装置
１２の加熱制御器１５等の計装類を付帯設置す
る。
温度センサー１３は、仕上圧延機２を出て高周
波誘導加熱装置１２へ向かう圧延材５の表面温度
をトツプからボトムまで連続的に測定し、その測
定温度を演算器１４へ出力する。
演算器１４には圧延材５の図示Ｌ間移動時間
すなわちｔ＝Ｌ／Ｓ（但し、Ｌ：温度センサー１
３と高周波誘導加熱装置１２との距離、Ｓ：ラン
アウト・テーブル１の送り速度）の算式と第６図
に示すような放冷曲線、すなわち圧延材５の表面
温度と放冷時間との関係が予めデータとして貯蔵
してあり、例えば圧延材５のトツプ部(A)温度を前
記温度センサー１３が750℃と測定し、該温度を
演算器１４に出力すると、演算器１４はその温度
と前記圧延材のＬ間移動時間（ｔ）から、例えば
（ｔ）が５分であれば圧延材トツプ部(A)が高周波
誘導加熱装置１２に到達した時点の圧延材トツプ
部（A′）の温度700℃を瞬時に算出する。
続いて演算器１４は上記算出温度を演算器に貯
蔵してある所定の焼入温度まで上昇せしめるに
必要な誘導加熱装置１２の高周波電流量（Ｙ）を
算出し、誘導加熱装置１２のコイルに流す高周波
電流量をコントロールしている加熱制御器１５に
対し、高周波電流量を前記（Ｙ）にコントールす
る信号Y′を出力する。
加熱制御器１５は、圧延材５のトツプ部(A)が実
際に高周波誘導加熱装置１２に到達した時点で、
誘導加熱装置１２のコイルに流す高周波電流量を
前記演算器１４からの入力信号に基づいて自動制
御する。
同様にして圧延材５のトツプ部からボトム部に
到るまでの時々刻々の高周波電流量が自動制御さ
れ、圧延材５のトツプ部からボトム部まで、表面
温度はAc1またはAc3変態点以上の所定の焼入温
度（Ｐ）に再加熱される。
このようにして、トツプからボトムまで均一な
焼入温度に高周波誘導加熱された圧延材５は、
次いで直接焼入装置４に入り、上記の加熱表面に
水、油等の適当な冷却剤の噴射を受けて急冷さ
れ、焼入れられる。
次に実施例について記載する。
Ｃ：0.15％、Si：0.36％、Mn：1.28％、Ｐ：
0.015％、Ｓ：0.002％、Ｖ：0.03％、Al：0.05％
残部実質的にFeよりなるC.Cスラブを熱間圧延ラ
インで25mm厚×3m巾×28m長の鋼板に仕上げた。
この時の仕上圧延温度は930℃であつた。次いで、
この鋼板を本発明方法に従つて870℃に高周波誘
導加熱した後、直ちに下記条件で焼入を行なつ
た。
（焼入条件）
焼入速度 20m／min
比水量 ２m3／secm2
水 圧 ５Kg／cm2
水 温 20℃
上記焼入条件にて焼入を行なつた鋼板を680℃
で焼戻し、第７図に示す如く鋼板のトツプ部、ミ
ドル部、ボトム部より試験片を採取し、各試験片
に引張試験を実施した。
従来例として、前記同様の成分からなるC.Cス
ラブを熱間圧延ラインにて仕上圧延温度930℃で
前記同様の寸法の鋼板に仕上げ、高周波誘導加熱
を行なわず、そのまま前記同様の焼入条件で直接
焼入を行なつた後、680℃で焼戻し、該鋼板のト
ツプ部、ミドル部、ボトム部より採取した試験片
に同様の引張試験を行なつた。
結果は第２表に見る如く、本発明法による試験
片は降伏点、抗張力、伸び、衝撃値がいずれもト
ツプ部、ミドル部、ボトム部で均等しており、鋼
板長手方向に均一な機械的性質を有することが明
らかとなつた。
一方、従来例の試験片では降伏点、抗張力、伸
び、衝撃値の各数値がトツプ部、ミドル部、ボト
ム部で大きく異なり、鋼板長手方向の機械的性質
にバラツキが発生していた。[Table] Figure 2 shows the results of continuous measurement of the surface temperature of a rolled material (25mm thick x 20m long) at the start of direct quenching from top to bottom. The surface temperature is higher toward the top, and gradually decreases toward the bottom due to cooling. In view of this situation, the present inventor installed a high-frequency induction heating device capable of rapid heating immediately before the entry side of the quenching device in this type of direct quenching to increase the temperature on the bottom side of the rolled material as shown in FIG. The present invention was completed after various experiments and research to compensate for the drop. That is, the present invention provides a hardening device on the exit side of a finishing rolling mill, and in direct hardening in which the rolled material is hardened in a hot rolling line, a high-frequency induction heating device is installed before the entry side of the hardening device. At the same time, the temperature of the rolled material is measured at the stage before it exits the finishing mill and enters the high-frequency induction heating device, the measured temperature is input to a computing device, and a heating control device connected to the computing device is used to measure the temperature of the rolled material during quenching. The gist of the present invention is a direct quenching method for hot-rolled materials, in which the high-frequency current of the high-frequency induction heating device is controlled so that the quenching temperature is constant from the top to the bottom of the rolled material. Hereinafter, the configuration of the present invention will be explained based on the accompanying drawings. Figure 3 is a diagram explaining conventional direct quenching, showing the final part of the hot rolling line, in which 1 is a runout table, 2 is a finishing mill, 3 is a leveler,
4 is a direct hardening device, and 5 is a rolled material. The rolled material 5 rolled to a desired thickness by the finishing mill 2 is transferred onto the runout table 1 to the leveler 3, where it is flattened and then transferred directly to the quenching device. Sent to 4. As shown in FIG. 4, the direct hardening device 4
It consists of frames 6, 6' that face each other vertically across the running line of the frame, and a gate-shaped frame 7 that supports the frames 6, 6'. It can be moved up and down by a mechanism, and can respond to changes in the thickness of the rolled material 5. The upper and lower frames 6, 6' are provided with pinch rolls 9, 9' on the inlet side (arrow) of the rolled material 5, and following the pinch rolls 9, 9', a coolant is spouted to the outlet side of the rolled material 5. Nozzles 10 and press rolls 11 for rolling material are attached alternately. The rolled material 5 fed between the upper and lower frames 6, 6' in the direction of the arrow moves continuously from the inlet side to the outlet side without stopping, and during that time, it is affected by the coolant injected from the nozzles 10. It is then hardened and sent out from the device 4. In the method of the present invention, as shown in the block diagram of FIG.
2, and a temperature sensor 13 for detecting the surface temperature of the rolled material 5 is provided at a predetermined position between the high frequency induction heating device 12 and the finishing rolling mill 2 (in the illustrated example, behind the leveler 3). Furthermore, instrumentation such as a computing unit 14 and a heating controller 15 of the high-frequency induction heating device 12 are additionally installed. The temperature sensor 13 continuously measures the surface temperature of the rolled material 5 leaving the finishing mill 2 and heading toward the high-frequency induction heating device 12 from top to bottom, and outputs the measured temperature to the computing unit 14 . The calculation unit 14 calculates the moving time of the rolled material 5 between L as shown in the figure, that is, t=L/S (L: temperature sensor 1
3 and the high-frequency induction heating device 12, S: the feed speed of the runout table 1) and the cooling curve as shown in FIG. 6, that is, the relationship between the surface temperature of the rolled material 5 and the cooling time. For example, when the temperature sensor 13 measures the temperature of the top part (A) of the rolled material 5 at 750°C and outputs the temperature to the computing unit 14, the computing unit 14 stores that temperature and the temperature of the rolled material 5 in advance as data. For example, if (t) is 5 minutes, the temperature of the top part (A') of the rolled material at the time when the top part (A) of the rolled material reaches the high-frequency induction heating device 12 is 700. Instantly calculate ℃. Subsequently, the computing unit 14 calculates the amount of high-frequency current (Y) of the induction heating device 12 necessary to raise the above-mentioned calculated temperature to a predetermined quenching temperature stored in the computing device, and applies it to the coil of the induction heating device 12. A signal Y' for controlling the amount of high frequency current to the above (Y) is output to the heating controller 15 which controls the amount of high frequency current flowing. When the top part (A) of the rolled material 5 actually reaches the high frequency induction heating device 12, the heating controller 15
The amount of high-frequency current flowing through the coil of the induction heating device 12 is automatically controlled based on the input signal from the arithmetic unit 14. Similarly, the amount of high-frequency current from the top to the bottom of the rolled material 5 is automatically controlled, and the surface temperature from the top to the bottom of the rolled material 5 is maintained at the Ac 1 or Ac 3 transformation point or higher. is reheated to a predetermined quenching temperature (P). In this way, the rolled material 5 is heated by high frequency induction to a uniform quenching temperature from top to bottom.
Then, it enters a direct quenching device 4, where it is rapidly cooled and quenched by spraying a suitable coolant such as water or oil onto the heated surface. Next, examples will be described. C: 0.15%, Si: 0.36%, Mn: 1.28%, P:
0.015%, S: 0.002%, V: 0.03%, Al: 0.05%
The CC slab, the remainder of which was essentially Fe, was finished on a hot rolling line into a steel plate with a thickness of 25 mm, width of 3 m, and length of 28 m.
The finish rolling temperature at this time was 930°C. Then,
After this steel plate was high-frequency induction heated to 870°C according to the method of the present invention, it was immediately quenched under the following conditions. (Quenching conditions) Quenching speed: 20 m/min Specific water amount: 2 m 3 /secm 2 Water pressure: 5 Kg/cm 2 Water temperature: 20°C A steel plate quenched under the above quenching conditions was heated to 680°C.
After tempering, test pieces were taken from the top, middle, and bottom parts of the steel plate as shown in FIG. 7, and a tensile test was conducted on each test piece. As a conventional example, a CC slab made of the same components as above was finished into a steel plate with the same dimensions as above at a finishing rolling temperature of 930°C on a hot rolling line, and then directly processed under the same quenching conditions as above without high-frequency induction heating. After quenching, the steel plate was tempered at 680°C, and a similar tensile test was conducted on test pieces taken from the top, middle, and bottom parts of the steel plate. As shown in Table 2, the yield point, tensile strength, elongation, and impact value of the test specimens produced by the method of the present invention were all uniform at the top, middle, and bottom parts, and the mechanical strength was uniform in the longitudinal direction of the steel plate. It has become clear that it has the following properties. On the other hand, in the conventional test specimen, the values of yield point, tensile strength, elongation, and impact value differed greatly between the top, middle, and bottom parts, and variations occurred in the mechanical properties in the longitudinal direction of the steel plate.
第１図は、従来の直接焼入方法による圧延材の
トツプ、ボトム間の引張強度差を表わしたグラ
フ、第２図は従来の直接焼入における焼入開始時
点での圧延材をトツプからボトムまで連続的に測
定した結果を示す温度曲線図、第３図は従来の直
接焼入のラインを示す説明図、第４図は直接焼入
装置の構造図、第５図は本発明の直接焼入方法の
ブロツク説明図、第６図は圧延材の放冷曲線図、
第７図は試験片の採取位置を示す説明図である。
４：直接焼入装置、１２：高周波誘導加熱装
置、１３：温度センサー、１４：演算器、１５：
加熱制御器。
Figure 1 is a graph showing the difference in tensile strength between the top and bottom of the rolled material obtained by the conventional direct quenching method. Figure 3 is an explanatory diagram showing the conventional direct quenching line, Figure 4 is a structural diagram of the direct quenching equipment, and Figure 5 is the direct quenching system of the present invention. A block explanatory diagram of the feeding method, Figure 6 is a cooling curve diagram of the rolled material,
FIG. 7 is an explanatory diagram showing the sampling position of the test piece. 4: Direct quenching device, 12: High frequency induction heating device, 13: Temperature sensor, 14: Arithmetic unit, 15:
Heating controller.
Claims (1)
延ライン上で圧延材の焼入を行なう直接焼入にお
いて、上記焼入装置の入側の前に高周波誘導加熱
装置を設けるとともに、仕上圧延機を出て高周波
誘導加熱装置に入る前の段階で圧延材の温度を測
定し、該測定温度を演算器に入力し、演算器に接
続した加熱制御装置により、圧延材がトツプから
ボトムまで一定の焼入温度となるよう前記高周波
誘導加熱装置の高周波電流を制御することを特徴
とする熱間圧延材の直接焼入方法。1. In direct quenching in which a quenching device is provided on the exit side of a finishing rolling mill and the rolled material is quenched on a hot rolling line, a high frequency induction heating device is provided in front of the entry side of the quenching device, and The temperature of the rolled material is measured before it leaves the finishing mill and enters the high-frequency induction heating device, and the measured temperature is input to a computer, and the heating control device connected to the computer controls the temperature of the rolled material from the top to the bottom. 1. A method for directly quenching hot-rolled materials, comprising controlling the high-frequency current of the high-frequency induction heating device so as to maintain a constant quenching temperature.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56186618A JPS5887216A (en) | 1981-11-19 | 1981-11-19 | Direct hardening method for hot rolled material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56186618A JPS5887216A (en) | 1981-11-19 | 1981-11-19 | Direct hardening method for hot rolled material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5887216A JPS5887216A (en) | 1983-05-25 |
| JPS6411687B2 true JPS6411687B2 (en) | 1989-02-27 |
Family
ID=16191725
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56186618A Granted JPS5887216A (en) | 1981-11-19 | 1981-11-19 | Direct hardening method for hot rolled material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5887216A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100471244B1 (en) * | 2002-07-12 | 2005-03-08 | 현대자동차주식회사 | A high frequency heat treatment device and control method thereof |
-
1981
- 1981-11-19 JP JP56186618A patent/JPS5887216A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5887216A (en) | 1983-05-25 |
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