JP3986864B2

JP3986864B2 - Quenching method and quenching apparatus

Info

Publication number: JP3986864B2
Application number: JP2002094301A
Authority: JP
Inventors: 三郎山方; 博充村上; 秀雄横田; 聡須田; 浩之星野
Original assignee: Nippon Oil Corp
Current assignee: Eneos Corp
Priority date: 2002-03-29
Filing date: 2002-03-29
Publication date: 2007-10-03
Anticipated expiration: 2022-03-29
Also published as: JP2003286517A

Description

【０００１】
【発明の属する技術分野】
本発明は、金属の熱処理における焼入れ方法及び焼入れ装置に関し、特に、焼入れ時の変形や歪みを抑えるために有効な技術に関する。
【０００２】
【従来の技術】
一般に、焼入れは、鋼を変態点以上の温度に加熱した後、油、水、水溶性冷却剤などの適当な冷却液中に浸漬して急速に冷却する操作であり、例えば図２１に示すような焼入れ装置が使用される。この焼入れ装置は、焼入れ材である冷却液１を貯えた冷却槽２と、この冷却槽２内に片寄せて配設されたプロペラ攪拌機３と、プロペラ攪拌機３による冷却槽２内の液流（流れ）４を槽底から上部に向かうように整える整流板５とを備えている。もっとも、プロペラ攪拌機３の代わりに噴流用ポンプを用いるものもある。
【０００３】
この焼入れ装置を用いて、鋼製又は特殊鋼製の被処理物（以下、ワークという）を焼入れ処理する方法は次の通りである。
すなわち、予めプロペラ攪拌機３を始動させて冷却槽２内に冷却液１の流れ４を作っておく。別途に加熱炉で変態点以上に加熱された高温のワークをバスケット等の容器６に収納し、これを冷却槽２の冷却液１に浸漬する。かくして冷却液の流れ４にさらすことによりワークは急冷され、硬化する。
【０００４】
【発明が解決しようとする課題】
この場合、容器６内のワークは、エレベータなどの昇降手段で下降させることで冷却液１中に浸漬され、焼入れが行われる。そのため、冷却は容器６の下部から始まり、徐々に上部が冷却される傾向がある。さらに、冷却液の流れ４が槽底部から上部に向かう上昇流であることも関与して、被処理物であるワークの全体を上部及び下部にわたって均一に冷却することは難しい。そのため、ワークが単体の場合は変形が起こり、またワークが多数個のロットの場合は、ロット全体でバラツキが発生してしまう。
【０００５】
それでもワークの数量やサイズが小さければ、プロペラ攪拌機３による冷却液１の流れ４の乱され方が少ないから、バラツキのない良好な焼入れが行われやすい。
しかしながら、一般的な焼入れ装置では、一度に重量で数百ｋｇから千ｋｇ程度のワークを焼入れする。そのため、冷却槽２内の流れ４が遮られてしまい、冷却槽２内におけるワークの位置、特に上部と下部とでは冷却速度が大きく異なり、冷却のバラツキが大きくなってしまう。その結果、ワークの焼入れ硬さや、歪み・曲がりなどの焼入れ変形にバラツキが生じてしまうという不具合があった。
【０００６】
ここで、熱処理に起因する歪み・曲がりなどの焼入れ変形が大きい場合には、熱処理後にワークの切削工程が必要となる。ところが、近年、熱処理部品の高精度化に伴い、歪み・曲がりなどの焼入れ変形を極力抑え、熱処理後の切削工程を省略することが切望されている。
本発明は、上記事情に鑑みてなされたものであり、焼入れ処理における冷却能のバラツキを抑制し、焼入れ時に発生する変形や歪みを抑制可能な焼入れ方法及び焼入れ装置を提供することを課題としている。
【０００７】
【課題を解決するための手段】
このような課題を解決するために、本発明者らが鋭意検討を行った結果、焼入れ時に被処理物の表面に形成される焼入れ油の蒸気膜が、被処理物の形状や位置により不均一に破壊されることで、歪み・曲がりなどの焼入れ変形を大きくしていることを発見し、本発明に至った。
【０００８】
本発明の第一の焼入れ方法は、焼入れ冷却槽内の冷却液に被処理物を浸漬する焼入れ方法において、前記冷却液を振動によって攪拌した後、噴流によって攪拌することを特徴としている。
本発明の第二の焼入れ方法は、焼入れ冷却槽内の冷却液に被処理物を浸漬する焼入れ方法において、前記冷却液を振動及び噴流によって攪拌した後、噴流によって攪拌することを特徴としている。
【０００９】
本発明の第三の焼入れ方法は、焼入れ冷却槽内の冷却液に被処理物を浸漬する焼入れ方法において、前記冷却液を振動によって攪拌した後、振動及び噴流によって攪拌し、さらにその後噴流によって攪拌することで冷却能のバラツキを抑制することを特徴としている。
本発明の第四の焼入れ方法は、焼入れ冷却槽内の冷却液に被処理物を浸漬する焼入れ方法において、前記冷却液を振動によって攪拌した後、振動及び噴流によって攪拌することを特徴としている。
【００１０】
ここで、本発明の第一乃至第四の焼入れ方法において「振動によって攪拌した後、噴流によって攪拌する」とは、振動による攪拌を停止すると同時に、噴流による攪拌を作動させるようにしてもよいし、振動による攪拌を完全に停止させてからしかる後に、噴流による攪拌を作動させるようにしてもよい。また、振動による攪拌を行っている途中から、噴流による攪拌を作動させるようにしてもかまわない。
【００１１】
本発明の第五の焼入れ方法は、焼入れ冷却槽内の冷却液に被処理物を浸漬する焼入れ方法において、前記冷却液の冷却過程である蒸気膜段階において、前記冷却液を振動によって攪拌するとともに、前記冷却液の冷却過程である対流段階において、前記冷却液を噴流によって攪拌することを特徴としている。
また、本発明の第五の焼入れ方法は、前記冷却液の冷却過程である沸騰段階において、前記冷却液の攪拌方法を、振動による攪拌から噴流による攪拌に切り替えることが好ましい。
【００１２】
ここで、本発明の第五の焼入れ方法において、冷却液の冷却過程である「蒸気膜段階」及び「沸騰段階」並びに「対流段階」とは、被処理物を加熱させた後冷却する時に、その温度と時間との変化における冷却液の状態変化を指す。
本発明の第六の焼入れ方法は、焼入れ冷却槽内の冷却液に被処理物を浸漬する焼入れ方法において、前記冷却液を、振動による攪拌及び噴流による攪拌の作動・停止を焼入れ中に個別に制御することで、攪拌することを特徴としている。
【００１３】
また、本発明の第六の焼入れ方法は、前記冷却液を、振動による攪拌及び噴流による攪拌の強さも個別に制御することで、攪拌することが好ましい。
本発明の第一の焼入れ装置は、焼入れ冷却槽内の冷却液に被処理物を浸漬する焼入れ装置において、前記冷却液を所定時間振動によって攪拌した後、噴流によって攪拌するように攪拌方法を制御するようになっていることを特徴としている。
【００１４】
本発明の第二の焼入れ装置は、焼入れ冷却槽内の冷却液に被処理物を浸漬する焼入れ装置において、前記冷却液を所定時間振動及び噴流によって攪拌した後、噴流によって攪拌するように攪拌方法を制御するようになっていることを特徴としている。
本発明の第三の焼入れ装置は、焼入れ冷却槽内の冷却液に被処理物を浸漬する焼入れ装置において、前記冷却液を所定時間振動によって攪拌した後、振動及び噴流によって攪拌し、さらにその後噴流によって攪拌するように攪拌方法を制御するようになっていることを特徴としている。
【００１５】
本発明の第四の焼入れ装置は、焼入れ冷却槽内の冷却液に被処理物を浸漬する焼入れ装置において、前記冷却液を所定時間振動によって攪拌した後、振動及び噴流によって攪拌するように攪拌方法を制御するようになっていることを特徴としている。
また、本発明の第一乃至第四の焼入れ装置において、前記振動を、複数枚の振動板からなる多段式振動攪拌器によって発生させるとともに、当該多段式振動攪拌器は、振動周波数を調整可能となっていることが好ましい。
【００１６】
本発明の第五の焼入れ装置は、焼入れ冷却槽内の冷却液に被処理物を浸漬する焼入れ装置において、前記冷却液の冷却過程である蒸気膜段階において、前記冷却液を振動によって攪拌するとともに、前記冷却液の冷却過程である対流段階において、前記冷却液を噴流によって攪拌するように攪拌方法を制御するようになっていることを特徴としている。
【００１７】
また、本発明の第五の焼入れ装置は、前記冷却液の冷却過程である沸騰段階において、前記冷却液の攪拌方法を、振動による攪拌から噴流による攪拌に切り替えるようになっていることが好ましい。
さらに、本発明の第五の焼入れ装置は、前記振動を、複数枚の振動板からなる多段式振動攪拌器によって発生させるとともに、当該多段式振動攪拌器は、振動周波数を調整可能となっていることが好ましい。
【００１８】
本発明の第一の焼入れ方法によれば、被処理物を冷却する冷却液を振動によって攪拌した後、噴流によって攪拌することによって、焼入れ時に被処理物表面に形成される冷却液（焼入れ油）の蒸気膜を振動攪拌により均一に破壊するとともに、取り除いた蒸気を噴流攪拌により均一に拡散消失させることが可能となる。このため、冷却能のバラツキをなくし、焼入れ時に発生する被処理物の歪み・曲がりなどの焼入れ変形を抑制することが可能となる。
【００１９】
本発明における第二乃至第四の焼入れ方法によれば、被処理物の形状や容器の大きさに合わせて、振動と噴流の組み合わせを変化させることで、被処理物に応じた最適な攪拌を行うことが可能となる。
本発明の第五の焼入れ方法によれば、冷却液の冷却過程である蒸気膜段階において、冷却液を振動によって攪拌するとともに、冷却液の冷却過程である対流段階において、冷却液を噴流によって攪拌することによって、蒸気膜段階において、焼入れ時に被処理物表面に形成される蒸気膜を均一に破壊するとともに、その後の沸騰段階及び対流段階において、被処理物表面から取り除いた蒸気を均一に拡散消失させることができる。よって、強い冷却能のままで、焼入れ時に発生する被処理物の歪み・曲がりなどの焼入れ変形を抑制することが可能となる。
【００２０】
本発明の第六の焼入れ方法によれば、冷却液を、振動による攪拌及び噴流による攪拌の作動・停止を焼入れ中に個別に制御するとともに、振動による攪拌及び噴流による攪拌の強さも個別に制御することで攪拌することによって、被処理物の形状や容器の大きさに応じた最適な攪拌を行うことが可能となる。よって、冷却能のバラツキをなくし、焼入れ時に発生する被処理物の歪み・曲がりなどの焼入れ変形を抑制することが可能となる。
【００２１】
本発明の焼入れ装置によれば、本発明の焼入れ方法を容易に実現することができる。
【００２２】
【発明の実施の形態】
以下、本発明の実施の形態について図面を参照して説明する。
図１は、本発明における焼入れ装置の一実施形態を模式的に示し、（ａ）は正断面図、（ｂ）は図１（ａ）におけるｂ−ｂ線に沿った断面図である。なお、従来と同一部分には、同一符号を付してある。
【００２３】
本実施形態における焼入れ装置は、図１に示すように、冷却液１を貯えた冷却槽２と、この冷却槽２の中央部に配設され、焼入れ処理がなされるワーク（被処理物）を収納する容器６と、この冷却槽２内に片寄せて配置される振動攪拌機１０と、容器６の下方を噴流攪拌管２２が横切るように配置された噴流攪拌機２０と、振動攪拌機１０と噴流攪拌機２０との切り替えやそれぞれの攪拌強度の調整を行う制御器３０とを備えている。
【００２４】
振動攪拌機１０は、等間隔で上下に配列した多段の振動板１０ａを有し、冷却液１を振動によって攪拌する多段式振動装置である。振動板１０ａの段数は、ワークを収納する容器６の高さ（深さ）に合わせて決められる。
これらの振動板１０ａは、共通の軸１０ｂを介して連結され、冷却液１に没入させてある。ここで、軸１０ｂの端部は、振動の周波数を調整する周波数調整手段として周波数調整器（図示せず）を内蔵した駆動装置１１に接続されている。
【００２５】
周波数調整器は、焼入れされるワークの形状や材質に応じて、冷却過程で振動周波数を変化させることで、振動による攪拌の強度を調整可能となっている。
噴流攪拌機２０は、噴流を送り出す噴流ポンプ２１と、噴流を搬送する噴流管２２と、噴流を冷却槽２の内壁に対向して噴出する噴出口２３とを備えている。この噴出口２３から噴出した噴流は、冷却槽２の下部より上部に向かう上昇流となり、冷却液１を噴流によって攪拌する。この噴流の噴出量は、焼入れされるワークの形状や材質に応じて、噴流による攪拌の強度を調整可能となっている。
【００２６】
すなわち、図２１に示した従来例のプロペラ攪拌機３による上昇液流４の代わりに、噴流ポンプ２１により上昇噴流を形成するようにしている。
制御器３０は、焼入れされるワークの形状や材質に応じて、振動攪拌機１０及び噴流攪拌機２０との切り替えを行うタイミングを制御している。また、振動攪拌機１０における攪拌の強度を調整するために、周波数調整器の制御を行うとともに、噴流攪拌機２０における攪拌の強度を調整するために、噴流ポンプ２２から噴出される噴出量の制御を行っている。
【００２７】
次に、上記構成を有する焼入れ装置を用いた焼入れ方法について説明する。図２は、振動攪拌及び噴流攪拌の作動状態を示すタイムチャートである。
まず、振動攪拌機１０を作動させ、冷却槽２内に冷却液１において水平方向の振動流４を形成する。そして、別途に加熱炉で変態点以上に加熱させた高温のワークを容器６内に収納し、例えば、エレベータ（図示せず）で冷却槽２の冷却液１内に浸漬させる。
【００２８】
次いで、図２に示すように、振動攪拌機１０による振動攪拌を所定時間行い、ワーク表面が蒸気膜に覆われた蒸気膜段階が終了し、沸騰段階になった時点で振動攪拌機１０の作動を切り替えて、噴流攪拌機２０を作動させる。ここで、振動攪拌機１０及び噴流攪拌機２０が完全に切り替わるまでには所定時間を要する。このため、この時間を見込んで振動攪拌機１０と噴流攪拌機２０とを切り替えるタイミングを決定する。
【００２９】
ここで、振動攪拌機１０及び噴流攪拌機２０とを切り替えるタイミングは、焼入れするワークの形状、材料、或いは大きさなどによって決定することが望ましい。このタイミングの決定方法としては、例えば、予め振動或いは噴流による攪拌の様々な組み合わせパターンを試行し、焼入れするワークに最適なタイミングを決定するようにしてもよい。また、焼入れするワークに応じて、冷却液の冷却過程における蒸気膜段階、沸騰段階、及び対流段階の発生時間を予め測定しておき、それらの冷却過程発生時間に合わせてタイミングを決定するようにしてもよい。
【００３０】
そして、沸騰段階及び対流段階のワークを噴流攪拌機２０による噴流攪拌により冷却することで、ワークを焼入れする。
本実施形態における焼入れ方法によれば、冷却液１の蒸気膜段階において冷却液１に振動を加えることによって攪拌することで、冷却槽１内の冷却液１には、水平方向の振動流４が形成され、容器６内の上部、中部、下部を横断しつつワークの蒸気膜を均一に破壊することができる。
【００３１】
また、冷却液１の沸騰段階及び対流段階において、冷却液１を噴流によって攪拌することで、振動攪拌によって除去された蒸気を、素早く全体に拡散消失させ、冷却の均一性を向上させることができる。
すなわち、冷却液を振動によって攪拌した後、噴流によって攪拌することで、ワーク全体が均一に硬化し、歪み・曲がりなどの焼入れ変形を抑制することが可能となる。
【００３２】
ここで、本実施形態の焼入れ方法によれば、冷却液１の冷却状態が蒸気膜段階において、振動による攪拌のみを行い、冷却液１の冷却状態が沸騰段階及び対流段階において、噴流による攪拌のみを行うようにしたが、少なくとも冷却開始時に振動攪拌機１０を作動させ、冷却終了時に噴流攪拌機２０を作動させるようにするのであれば、これに限らない。例えば、図３に示すように、冷却開始時に振動攪拌及び噴流攪拌を行い、所定時間経過後、噴流攪拌のみを行うようにしてもよい。また、図４に示すように、冷却開始時に振動攪拌を行い、所定時間経過後、振動攪拌及び噴流攪拌を同時に行い、さらにその後、噴流攪拌のみを行うようにしてもよい。さらに、図５に示すように、冷却開始時に振動攪拌を行い、所定時間経過後、振動攪拌及び噴流攪拌を同時に行うようにしてもよい。
【００３３】
また、振動攪拌及び噴流攪拌の攪拌状況は、焼入れされるワークの形状や材質に応じて変更可能であり、例えば、図６に示すように、冷却開始時には強振動により攪拌を行い、所定時間経過後に弱振動による攪拌に切り替え、さらに所定時間経過後には振動による攪拌は停止し、噴流により攪拌を行うようにしてもよい。また、図７に示すように、冷却開始時には強振動により攪拌を行い、所定時間経過後に弱振動及び強噴流による攪拌に切り替え、さらに所定時間経過後には振動による攪拌は停止し、強噴流のみにより攪拌を行うようにしてもよい。さらに、図８に示すように、冷却開始時には強振動により攪拌を行い、所定時間経過後に弱振動及び強噴流による攪拌に切り替え、さらに所定時間経過後には振動による攪拌は停止し、弱噴流のみによる攪拌に切り替えるようにしてもよい。さらに、図９に示すように、冷却開始時には強振動及び弱噴流により攪拌を行い、所定時間経過後に弱振動及び強噴流による攪拌に切り替え、さらに所定時間経過後には振動による攪拌は停止し、弱噴流のみにより攪拌を行うようにしてもよい。
【００３４】
さらに、本実施形態の焼入れ方法において、振動攪拌機１０及び噴流攪拌機２０の切り替え及びそれらの攪拌強度の調整は制御器３０によって行うようにしたが、これに限らず、手作業で行うようにしてもかまわない。
【００３５】
【実施例】
次に、本発明の効果を、以下の実施例に基づいて検証する。
加熱炉にて、焼入れ温度（８３０℃）まで加熱したＣ型試験片（ＳＵＪ２）を冷却槽中に投入し、以下の条件下において焼入れを行った。
（１）冷却方法
（本発明例）
実施例１）振動攪拌を４秒間行った後、噴流攪拌を行う。
実施例２）振動攪拌を８秒間行った後、噴流攪拌を行う。
実施例３）振動攪拌を１２秒間行った後、噴流攪拌を行う。
実施例４）振動攪拌を１６秒間行った後、噴流攪拌を行う。
【００３６】
ここで、振動攪拌を所望時間行った後、この振動攪拌機の作動を停止し、代わりに噴流攪拌機を作動させ、攪拌機の切り替えが完了するまでに約４秒要した。この切り替えが完了するまでの時間は、振動攪拌及び噴流攪拌が同時に行われていることになる。
（比較例）
比較例１）噴流攪拌のみを行う。
比較例２）振動攪拌のみを行う。
比較例３）振動攪拌と噴流攪拌を同時に行う。
比較例４）噴流攪拌を８秒間行った後、振動攪拌を行う。
（２）冷却条件

振動攪拌の強さについては、予備実験により流量と振動周波数との関係を求めたところ、図１０に示す直線関係が得られた。
【００３７】
冷却速さについては、遅い速いは冷却油の種類により大きく異なってくる。そこで、上記冷却油種ＦＷ２４３について、予備実験により温度８５０℃から３００℃までの冷却速さ（秒数）と振動周波数との関係を求めたところ、図１１の関係が得られた。すなわち、振動周波数が１０Ｈｚから３０Ｈｚまでは冷却秒数が６０秒台に略一定に維持し、周波数３０Ｈｚを超えると、次第に速くなり、周波数４０Ｈｚで冷却秒数４５秒と最も速くなっていることが分かる。一方、周波数４０Ｈｚを超えるとこんどは次第に遅くなり、周波数６０秒を若干上回ってしまう。ところが、周波数６０Ｈｚで冷却秒数は６０秒を超えると、逆に急に早くなる。
【００３８】
このように、振動周波数の変化により冷却速さが変化するが、周波数が１０Ｈｚ未満になると冷却が遅れて良好な焼入れ結果が得られず、一方、周波数６０Ｈｚを超えると油の粘度にもよるが振動が空回りの状態となり、やはり良好な焼入れ結果が得られない。この結果から、冷却油種ＦＷ２４３を冷却液とする本実施例においては、最適な振動周波数として４０Ｈｚを採用した。
【００３９】
これにあわせて、噴流攪拌における噴流の流量を、振動周波数４０Ｈｚに対応すべく５ｍ ^３／Ｈｒとした。
そして、それぞれの冷却方法によって焼入れされた試験片において、焼入れ前後における試験片の歪み量と、内部硬化度とを以下の試験条件に基づいて算出した。図１２は、試験片の歪み量を示す図である。図１３〜図１９はそれぞれの冷却条件で焼入れした試験片の内部硬度を示す図である。なお、図１３〜図１９はいずれも、同一容器内に、振動攪拌機側から順に所定間隔を空けて配置したＮｏ．１〜Ｎｏ．３の試験片についての内部硬度を示している。図２０は、被処理物の冷却時間と、被処理物の冷却状態との関係を示す図である。
（歪み量試験条件）
８３０℃、６０分間の加熱条件で焼入れを行い、その焼入れ前後の試験片の開口部をマイクロメータによって測定し、その寸法の変化を歪み量とした。
（内部硬度測定条件）
８３０℃、６０分間の加熱条件で焼入れを行い、その焼入れ後の試験片における最大厚み部の内部硬度を、ビッカース硬さ計を用いて測定した。
【００４０】
図１２に示す結果より、噴流攪拌のみを行った比較例１及び振動攪拌のみを行った比較例２と比べて、振動攪拌を行った後噴流攪拌を行った実施例１〜４及び振動攪拌と噴流攪拌とを同時に行った比較例３においては、試験片の歪み量が少ないことが分かる。また、実施例とは逆に、噴流攪拌を行った後振動攪拌を行った比較例４においても、比較例１及び比較例２と同様に試験片の歪み量が大きいことが分かる。このことより、振動攪拌及び噴流攪拌の組み合わせを変更することで、歪み量に変化が生じることが分かった。つまり、被処理物の形状、材質に応じて、振動攪拌及び噴流攪拌の組み合わせを調整することによって、歪みを調整可能であることが確認できた。
【００４１】
また、図１３〜図１９に示す結果より、噴流攪拌のみを行った比較例１及び振動攪拌のみを行った比較例２、並びに振動攪拌と噴流攪拌とを同時に行った比較例３においては、内部硬度にバラツキが生じることが確認された。このことより、均一な硬度を確保するためには、冷却液に振動攪拌及び噴流攪拌をともに行うとともに、振動攪拌と噴流攪拌との作動順序が重要であることが分かる。また、振動攪拌を１２秒以上行った後噴流攪拌を行った実施例３及び実施例４においても、内部硬度にバラツキが生じていることが確認された。このことより、均一な硬度を確保するためには、振動による攪拌から噴流による攪拌への切り替えタイミングが重要であることが分かる。
【００４２】
さらに、図２０に示す結果より、冷却液の冷却状態は、いずれの冷却条件の場合であっても、おおむね冷却を開始してから約４秒後に蒸気膜段階から沸騰段階に変化し、さらに、冷却を開始してから約１０秒後には沸騰段階から対流段階に変化していることが分かる。つまり、実施例１及び実施例２を実現するためには、振動攪拌及び噴流攪拌の切り替えにかかる時間を考慮して、冷却液の冷却状態が蒸気膜段階（冷却開始時から約８秒程度まで）においては、振動攪拌を行い、冷却液の冷却状態が沸騰段階及び対流段階の適切なタイミングにおいては、噴流攪拌を行うようにすればよいことが分かる。
【００４３】
すなわち、上記結果より、冷却液の冷却過程が蒸気膜段階においては振動によって攪拌し、冷却液の冷却過程が沸騰段階及び対流段階においては噴流によって攪拌した実施例１及び２において、歪み・曲がりなどの焼入れ変形が抑制され、均一な硬度を有する焼入れ処理がなされたことが確認できた。
【００４４】
【発明の効果】
以上説明したように、本発明の焼入れ方法によれば、振動による攪拌と噴流による攪拌とを組み合わせて、被処理物を冷却する冷却液を振動によって攪拌した後、噴流によって攪拌することによって、焼入れ時に被処理物表面に形成される焼入れ油の蒸気膜を振動攪拌により均一に破壊するとともに、取り除いた蒸気を噴流攪拌により均一に拡散消失させることが可能となる。このため、冷却能のバラツキを抑制し、焼入れ時に発生する被処理物の歪み・曲がりなどの焼入れ変形を抑制することが可能となる。
本発明の焼入れ装置によれば、本発明の焼入れ方法を容易に実現することが可能となる。
【図面の簡単な説明】
【図１】本発明における焼入れ装置の一実施形態を模式的に示し、（ａ）は正断面図、（ｂ）は図１（ａ）におけるｂ−ｂ線に沿った断面図である。
【図２】振動攪拌及び噴流攪拌の一作動状態を示すタイムチャートである。
【図３】振動攪拌及び噴流攪拌の他の作動状態を示すタイムチャートである。
【図４】振動攪拌及び噴流攪拌の他の作動状態を示すタイムチャートである。
【図５】振動攪拌及び噴流攪拌の他の作動状態を示すタイムチャートである。
【図６】被処理物の冷却時間に対する振動攪拌及び噴流攪拌の作動状態の一実施形態を示すタイムチャートである。
【図７】被処理物の冷却時間に対する振動攪拌及び噴流攪拌の作動状態の他の実施形態を示すタイムチャートである。
【図８】被処理物の冷却時間に対する振動攪拌及び噴流攪拌の作動状態の他の実施形態を示すタイムチャートである。
【図９】被処理物の冷却時間に対する振動攪拌及び噴流攪拌の作動状態の他の実施形態を示すタイムチャートである。
【図１０】振動攪拌における噴流の流量と、振動周波数との関係を示すグラフである。
【図１１】本発明における振動周波数と、冷却速度との関係を示すグラフである。
【図１２】焼入れ方法における歪み発生量を示すグラフである。
【図１３】振動攪拌のみによって焼入れを行った場合の内部硬度を示すグラフである。
【図１４】噴流攪拌のみによって焼入れを行った場合の内部硬度を示すグラフである。
【図１５】振動攪拌を４秒間行った後、噴流攪拌を行うようにした焼入れ方法における内部硬度を示すグラフである。
【図１６】振動攪拌を８秒間行った後、噴流攪拌を行うようにした焼入れ方法における内部硬度を示すグラフである。
【図１７】振動攪拌を１２秒間行った後、噴流攪拌を行うようにした焼入れ方法における内部硬度を示すグラフである。
【図１８】振動攪拌を１６秒間行った後、噴流攪拌を行うようにした焼入れ方法における内部硬度を示すグラフである。
【図１９】振動攪拌と噴流攪拌を同時に行うようにした焼入れ方法における内部硬度を示すグラフである。
【図２０】被処理物の冷却時間と、冷却液の冷却状態との関係を示す図である。
【図２１】従来の焼入れ装置の一実施形態を模式的に示す正断面図である。
【符号の説明】
１冷却液
２冷却槽
３プロペラ攪拌機
４振動流（流れ）
６容器
１０振動攪拌機 (振動攪拌手段）
２０噴流攪拌機（噴流攪拌手段）
３０制御器[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a quenching method and a quenching apparatus in heat treatment of metal, and in particular, deformation and distortion during quenching.suppressFor effective technology.
[0002]
[Prior art]
In general, quenching is an operation in which steel is heated to a temperature equal to or higher than the transformation point and then rapidly cooled by dipping in an appropriate coolant such as oil, water, or a water-soluble coolant. For example, as shown in FIG. A quenching device is used. This quenching apparatus includes a cooling tank 2 that stores a cooling liquid 1 that is a quenching material, a propeller stirrer 3 that is arranged in the cooling tank 2 and a liquid flow in the cooling tank 2 by the propeller stirrer 3 ( And a current plate 5 for adjusting the flow 4 from the bottom to the top. However, there is also a pump that uses a jet pump instead of the propeller stirrer 3.
[0003]
A method of quenching a workpiece (hereinafter referred to as a workpiece) made of steel or special steel using this quenching apparatus is as follows.
That is, the propeller stirrer 3 is started in advance to create a flow 4 of the coolant 1 in the cooling tank 2. Separately, a high-temperature work heated above the transformation point in a heating furnace is stored in a container 6 such as a basket, and this is immersed in the coolant 1 of the cooling tank 2. Thus, exposure to the coolant flow 4 quenches and hardens the workpiece.
[0004]
[Problems to be solved by the invention]
In this case, the work in the container 6 is immersed in the cooling liquid 1 by being lowered by lifting means such as an elevator, and quenching is performed. Therefore, cooling starts from the lower part of the container 6 and the upper part tends to be gradually cooled. Further, since the coolant flow 4 is an upward flow from the bottom of the tank to the top, it is difficult to uniformly cool the entire workpiece, which is a workpiece, over the top and the bottom. Therefore, when the work is a single piece, deformation occurs, and when the work is a lot of lots, variation occurs in the entire lot.
[0005]
If the number and size of the workpieces are still small, since the flow 4 of the coolant 1 by the propeller stirrer 3 is less disturbed, good quenching without variations is easily performed.
However, a general quenching apparatus quenches a workpiece of several hundred kg to 1,000 kg in weight at a time. As a result, the flow 4 in the cooling tank 2 is blocked, and the cooling rate differs greatly between the positions of the workpieces in the cooling tank 2, particularly the upper and lower parts, resulting in large variations in cooling. As a result, there has been a problem that variations occur in the quenching hardness of the workpiece and in the quenching deformation such as distortion and bending.
[0006]
Here, when quenching deformation such as distortion and bending caused by heat treatment is large, a workpiece cutting step is required after heat treatment. However, in recent years, with the increase in accuracy of heat-treated parts, there is a strong desire to suppress quenching deformation such as distortion and bending as much as possible and to omit the cutting process after heat treatment.
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a quenching method and a quenching apparatus capable of suppressing variations in cooling ability in quenching processing and suppressing deformation and distortion occurring during quenching. .
[0007]
[Means for Solving the Problems]
In order to solve such problems, the present inventors have conducted intensive studies. As a result, the vapor film of the quenching oil formed on the surface of the workpiece during quenching is uneven depending on the shape and position of the workpiece. It has been found that the quenching deformation such as distortion and bending is increased by being destroyed by the damage to the present invention.
[0008]
The first quenching method of the present invention is characterized in that, in the quenching method in which an object to be treated is immersed in a cooling liquid in a quenching cooling tank, the cooling liquid is stirred by vibration and then stirred by a jet.
The second quenching method of the present invention is characterized in that, in the quenching method in which an object to be treated is immersed in a cooling liquid in a quenching cooling tank, the cooling liquid is stirred by vibration and jet and then stirred by jet.
[0009]
The third quenching method of the present invention is a quenching method in which an object to be treated is immersed in a cooling liquid in a quenching cooling tank. After the cooling liquid is stirred by vibration, it is stirred by vibration and a jet, and further stirred by a jet. This is characterized by suppressing variations in cooling capacity.
A fourth quenching method of the present invention is characterized in that, in the quenching method in which an object to be treated is immersed in a cooling liquid in a quenching cooling tank, the cooling liquid is stirred by vibration and then stirred by vibration and jet flow.
[0010]
Here, in the first to fourth quenching methods of the present invention, “stirring by vibration and then stirring by jet” may stop stirring by vibration and simultaneously activate stirring by jet. The stirring by the jet may be activated after the stirring by the vibration is completely stopped. Further, the agitation by the jet may be activated in the middle of the agitation by vibration.
[0011]
The fifth quenching method of the present invention is a quenching method in which an object to be treated is immersed in a cooling liquid in a quenching cooling tank, and the cooling liquid is stirred by vibration in a vapor film stage which is a cooling process of the cooling liquid. In the convection stage that is the cooling process of the cooling liquid, the cooling liquid is agitated by a jet.
In the fifth quenching method of the present invention, it is preferable that the cooling liquid stirring method is switched from stirring by vibration to stirring by a jet in the boiling stage which is the cooling process of the cooling liquid.
[0012]
Here, in the fifth quenching method of the present invention, the “vapor film stage” and the “boiling stage” and the “convection stage”, which are cooling processes of the cooling liquid, are used when the workpiece is heated and then cooled. It refers to a change in the state of the coolant due to changes in temperature and time.
The sixth quenching method of the present invention is a quenching method in which an object to be treated is immersed in a cooling liquid in a quenching cooling tank, wherein the cooling liquid is individually stirred during quenching operation and stop of stirring by vibration and jet. It is characterized by stirring by controlling.
[0013]
In the sixth quenching method of the present invention, it is preferable to stir the cooling liquid by individually controlling the strength of stirring by vibration and the stirring by jet.
The first quenching apparatus of the present invention controls the stirring method so that the cooling liquid is stirred by vibration for a predetermined time and then stirred by a jet flow in the quenching apparatus in which the workpiece is immersed in the cooling liquid in the quenching cooling tank. It is characterized by being to do.
[0014]
The second quenching apparatus of the present invention is a quenching method in which an object to be treated is immersed in a cooling liquid in a quenching cooling tank. The stirring method is such that the cooling liquid is stirred by vibration and jet for a predetermined time and then stirred by jet. It is characterized by controlling.
The third quenching apparatus according to the present invention is a quenching apparatus in which a workpiece is immersed in a cooling liquid in a quenching cooling tank. After the cooling liquid is stirred by vibration for a predetermined time, the stirring is performed by vibration and jet flow, and then the jet flow is performed. The agitation method is controlled so as to agitate.
[0015]
The fourth quenching apparatus of the present invention is a quenching method in which an object to be treated is immersed in a cooling liquid in a quenching cooling tank, wherein the cooling liquid is stirred by vibration for a predetermined time and then stirred by vibration and jet flow. It is characterized by controlling.
Further, in the first to fourth quenching apparatuses of the present invention, the vibration is generated by a multistage vibration stirrer including a plurality of vibration plates, and the multistage vibration stirrer can adjust a vibration frequency. It is preferable that
[0016]
According to a fifth quenching apparatus of the present invention, in the quenching apparatus in which the workpiece is immersed in the cooling liquid in the quenching cooling tank, the cooling liquid is stirred by vibration in the vapor film stage which is the cooling process of the cooling liquid. In the convection stage, which is the cooling process of the cooling liquid, the stirring method is controlled so that the cooling liquid is stirred by a jet.
[0017]
In the fifth quenching apparatus of the present invention, it is preferable that the cooling liquid stirring method is switched from stirring by vibration to stirring by jet in the boiling stage, which is the cooling process of the cooling liquid.
Furthermore, in the fifth quenching apparatus of the present invention, the vibration is generated by a multistage vibration stirrer including a plurality of vibration plates, and the multistage vibration stirrer can adjust a vibration frequency. It is preferable.
[0018]
According to the first quenching method of the present invention, the cooling liquid (quenching oil) formed on the surface of the workpiece during quenching is obtained by stirring the cooling liquid for cooling the workpiece by vibration and then stirring by a jet. The vapor film can be uniformly broken by vibration stirring, and the removed vapor can be diffused and disappeared uniformly by jet stirring. For this reason, it is possible to eliminate variations in cooling capacity and to suppress quenching deformation such as distortion and bending of the workpiece that occurs during quenching.
[0019]
According to the second to fourth quenching methods of the present invention, the optimum stirring according to the object to be processed is achieved by changing the combination of vibration and jet according to the shape of the object to be processed and the size of the container. Can be done.
According to the fifth quenching method of the present invention, the cooling liquid is stirred by vibration in the vapor film stage that is the cooling process of the cooling liquid, and the cooling liquid is stirred by the jet flow in the convection stage that is the cooling process of the cooling liquid. As a result, in the vapor film stage, the vapor film formed on the surface of the workpiece during quenching is uniformly destroyed, and in the subsequent boiling and convection stages, the vapor removed from the surface of the workpiece is uniformly diffused and lost. Can be made. Therefore, it is possible to suppress quenching deformation such as distortion or bending of the workpiece that occurs during quenching while maintaining strong cooling ability.
[0020]
According to the sixth quenching method of the present invention, the cooling liquid is individually controlled during quenching for the stirring and the stirring by the jet and the stirring, and the strength of the stirring by the jet and the jet is also individually controlled. By doing so, it is possible to perform optimum stirring according to the shape of the object to be processed and the size of the container. Therefore, it is possible to eliminate variations in cooling capacity and to suppress quenching deformation such as distortion and bending of the workpiece that occurs during quenching.
[0021]
According to the quenching apparatus of the present invention, the quenching method of the present invention can be easily realized.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1A and 1B schematically show an embodiment of a quenching apparatus according to the present invention, in which FIG. 1A is a front sectional view and FIG. 1B is a sectional view taken along the line bb in FIG. In addition, the same code | symbol is attached | subjected to the same part as the past.
[0023]
As shown in FIG. 1, the quenching apparatus in the present embodiment includes a cooling tank 2 that stores a coolant 1 and a work (object to be processed) that is disposed in the center of the cooling tank 2 and is subjected to a quenching process. A container 6 to be housed, a vibration stirrer 10 disposed so as to be shifted to the inside of the cooling tank 2, a jet stirrer 20 disposed so that a jet stirrer tube 22 crosses the lower side of the container 6, and the vibration stirrer 10 and the jet stirrer 20 and a controller 30 for adjusting the stirring intensity.
[0024]
The vibration stirrer 10 is a multistage vibration device that has multistage vibration plates 10a arranged vertically at equal intervals and stirs the coolant 1 by vibration. The number of steps of the diaphragm 10a is determined according to the height (depth) of the container 6 that stores the workpiece.
These diaphragms 10 a are connected via a common shaft 10 b and are immersed in the coolant 1. Here, the end of the shaft 10b is connected to a drive device 11 incorporating a frequency adjuster (not shown) as frequency adjusting means for adjusting the frequency of vibration.
[0025]
The frequency adjuster can adjust the strength of stirring by vibration by changing the vibration frequency in the cooling process according to the shape and material of the workpiece to be quenched.
The jet stirrer 20 includes a jet pump 21 that sends out a jet, a jet pipe 22 that carries the jet, and a jet outlet 23 that jets the jet against the inner wall of the cooling tank 2. The jet flow ejected from the jet port 23 becomes an upward flow from the lower portion of the cooling tank 2 toward the upper portion, and the coolant 1 is stirred by the jet flow. The jet amount of the jet can adjust the strength of stirring by the jet according to the shape and material of the workpiece to be quenched.
[0026]
That is, instead of the rising liquid flow 4 by the propeller stirrer 3 of the conventional example shown in FIG. 21, the rising jet flow is formed by the jet pump 21.
The controller 30 controls the timing of switching between the vibration stirrer 10 and the jet flow stirrer 20 according to the shape and material of the workpiece to be quenched. Moreover, in order to adjust the intensity of stirring in the vibration stirrer 10, the frequency adjuster is controlled, and in order to adjust the intensity of stirring in the jet stirrer 20, the amount of ejection ejected from the jet pump 22 is controlled. ing.
[0027]
Next, a quenching method using the quenching apparatus having the above configuration will be described. FIG. 2 is a time chart showing operating states of vibration stirring and jet stirring.
First, the vibration stirrer 10 is operated to form a horizontal vibration flow 4 in the cooling liquid 1 in the cooling tank 2. And the high temperature workpiece | work heated separately more than the transformation point with the heating furnace is accommodated in the container 6, and it is immersed in the cooling fluid 1 of the cooling tank 2 with an elevator (not shown), for example.
[0028]
Next, as shown in FIG. 2, the vibration stirrer 10 is vibrated for a predetermined time, and the operation of the vibration stirrer 10 is switched when the vapor film stage in which the workpiece surface is covered with the vapor film is completed and the boiling stage is reached. Then, the jet stirrer 20 is operated. Here, a predetermined time is required until the vibration stirrer 10 and the jet stirrer 20 are completely switched. For this reason, the timing which switches the vibration stirrer 10 and the jet flow stirrer 20 is determined in consideration of this time.
[0029]
Here, the timing for switching between the vibration stirrer 10 and the jet stirrer 20 is desirably determined by the shape, material, size, or the like of the workpiece to be quenched. As a method for determining this timing, for example, various combinations of vibration or stirring by jetting may be tried in advance to determine the optimal timing for the workpiece to be quenched. In addition, according to the work to be quenched, the generation time of the vapor film stage, boiling stage and convection stage in the cooling process of the coolant is measured in advance, and the timing is determined according to the cooling process generation time. May be.
[0030]
And the workpiece | work is quenched by cooling the workpiece | work of a boiling stage and a convection stage by jet stirring by the jet stirrer 20. FIG.
According to the quenching method in the present embodiment, the cooling liquid 1 in the cooling tank 1 is stirred by applying vibration to the cooling liquid 1 in the vapor film stage of the cooling liquid 1, so that the horizontal vibration flow 4 is generated in the cooling liquid 1 in the cooling tank 1. Thus, the vapor film of the workpiece can be uniformly broken while traversing the upper, middle and lower portions in the container 6.
[0031]
  Moreover, in the boiling stage and convection stage of the cooling liquid 1, the cooling liquid 1 is agitated by a jet, so that the vapor removed by vibration stirring is quickly diffused and disappeared entirely.TheThe uniformity of cooling can be improved.
  That is, after the coolant is stirred by vibration and then stirred by a jet, the entire workpiece is uniformly cured, and quenching deformation such as distortion and bending can be suppressed.
[0032]
Here, according to the quenching method of the present embodiment, only the stirring by vibration is performed in the cooling state of the cooling liquid 1 in the vapor film stage, and only the stirring by the jet is performed in the cooling state of the cooling liquid 1 in the boiling stage and the convection stage. However, the present invention is not limited to this as long as the vibration stirrer 10 is operated at least at the start of cooling and the jet stirrer 20 is operated at the end of cooling. For example, as shown in FIG. 3, vibration stirring and jet stirring may be performed at the start of cooling, and only jet stirring may be performed after a predetermined time has elapsed. Further, as shown in FIG. 4, vibration agitation may be performed at the start of cooling, and after a predetermined time has elapsed, vibration agitation and jet agitation may be performed simultaneously, and then only the jet agitation may be performed. Furthermore, as shown in FIG. 5, vibration agitation may be performed at the start of cooling, and vibration agitation and jet agitation may be simultaneously performed after a predetermined time has elapsed.
[0033]
In addition, the stirring status of vibration stirring and jet stirring can be changed according to the shape and material of the workpiece to be quenched. For example, as shown in FIG. It is possible to switch to agitation by weak vibration later, and to stop the agitation by vibration after a predetermined time, and to perform agitation by jet. Also, as shown in FIG. 7, stirring is performed by strong vibration at the start of cooling, switching to weak vibration and stirring by a strong jet after a predetermined time has passed, and stirring by vibration is stopped after a predetermined time has passed, and only by a strong jet Stirring may be performed. Furthermore, as shown in FIG. 8, stirring is performed by strong vibration at the start of cooling, switching to weak vibration and stirring by a strong jet after a predetermined time has passed, and stirring by vibration is stopped after a predetermined time has passed and only by a weak jet. You may make it switch to stirring. Furthermore, as shown in FIG. 9, stirring is performed by strong vibration and weak jet at the start of cooling, switching to stirring by weak vibration and strong jet after a predetermined time has passed, and stirring by vibration is stopped after a predetermined time has passed. Stirring may be performed only by a jet.
[0034]
Furthermore, in the quenching method of the present embodiment, the switching between the vibration stirrer 10 and the jet flow stirrer 20 and the adjustment of the stirring intensity thereof are performed by the controller 30. However, the present invention is not limited to this and may be performed manually. It doesn't matter.
[0035]
【Example】
Next, the effects of the present invention will be verified based on the following examples.
A C-type test piece (SUJ2) heated to a quenching temperature (830 ° C.) in a heating furnace was put into a cooling bath and quenched under the following conditions.
(1) Cooling method
(Example of the present invention)
Example 1) After stirring for 4 seconds, jet stirring is performed.
Example 2) After stirring for 8 seconds, jet stirring is performed.
Example 3) Vibration stirring is performed for 12 seconds, and then jet stirring is performed.
Example 4) Vibration stirring is performed for 16 seconds, and then jet stirring is performed.
[0036]
Here, after the vibration agitation was performed for a desired time, the operation of the vibration agitator was stopped, and instead, the jet agitator was operated, and it took about 4 seconds to complete the switching of the agitator. For the time until this switching is completed, the vibration stirring and the jet stirring are performed simultaneously.
(Comparative example)
Comparative Example 1) Only jet stirring is performed.
Comparative Example 2) Only vibration stirring is performed.
Comparative Example 3) Vibration stirring and jet stirring are performed simultaneously.
Comparative Example 4) After stirring for 8 seconds, vibration stirring is performed.
(2) Cooling conditions

Regarding the strength of vibration stirring, when the relationship between the flow rate and the vibration frequency was determined by a preliminary experiment, the linear relationship shown in FIG. 10 was obtained.
[0037]
As for the cooling speed, the slow speed is greatly different depending on the kind of the cooling oil. Therefore, when the relationship between the cooling speed (seconds) from the temperature of 850 ° C. to 300 ° C. and the vibration frequency was determined for the cooling oil type FW243 by a preliminary experiment, the relationship of FIG. 11 was obtained. That is, when the vibration frequency is from 10 Hz to 30 Hz, the cooling time is maintained substantially constant on the order of 60 seconds, and when the frequency exceeds 30 Hz, the cooling frequency gradually increases, and at the frequency of 40 Hz, the cooling time is 45 seconds. I understand. On the other hand, when the frequency exceeds 40 Hz, it gradually becomes slower and slightly exceeds the frequency of 60 seconds. However, when the number of cooling seconds exceeds 60 seconds at a frequency of 60 Hz, it is rapidly accelerated.
[0038]
Thus, although the cooling speed changes due to the change of the vibration frequency, if the frequency is less than 10 Hz, the cooling is delayed and a good quenching result cannot be obtained. On the other hand, if the frequency exceeds 60 Hz, it depends on the viscosity of the oil. The vibration becomes idle and a good quenching result cannot be obtained. From this result, 40 Hz was adopted as the optimum vibration frequency in the present example using the cooling oil type FW243 as the coolant.
[0039]
  In accordance with this, the flow rate of the jet flow in jet stirring is set to 5 to correspond to the vibration frequency of 40 Hz.m ³/ Hr.
  And in the test piece hardened by each cooling method, the distortion amount of the test piece before and after quenching and the internal hardening degree were calculated based on the following test conditions. FIG. 12 is a diagram showing the strain amount of the test piece. 13-19 is a figure which shows the internal hardness of the test piece quenched by each cooling condition. 13 to 19 are all No. 1 arranged at predetermined intervals in order from the vibration stirrer side in the same container. 1-No. The internal hardness about the test piece of 3 is shown. FIG. 20 is a diagram illustrating the relationship between the cooling time of the object to be processed and the cooling state of the object to be processed.
(Strain test conditions)
  Quenching was performed at 830 ° C. for 60 minutes, the opening of the test piece before and after the quenching was measured with a micrometer, and the change in the dimension was taken as the amount of strain.
(Internal hardness measurement conditions)
  Quenching was performed at 830 ° C. for 60 minutes, and the internal hardness of the maximum thickness portion of the test piece after quenching was measured using a Vickers hardness meter.
[0040]
From the results shown in FIG. 12, compared with Comparative Example 1 in which only jet stirring was performed and in Comparative Example 2 in which only vibration stirring was performed, Examples 1 to 4 and vibration stirring in which jet stirring was performed after vibration stirring was performed. In Comparative Example 3 in which the jet agitation was performed simultaneously, it can be seen that the amount of distortion of the test piece is small. In contrast to Example, it can be seen that also in Comparative Example 4 in which the vibration stirring was performed after jet stirring, the amount of distortion of the test piece was large as in Comparative Examples 1 and 2. From this, it was found that the amount of distortion changes by changing the combination of vibration stirring and jet stirring. In other words, it was confirmed that the distortion can be adjusted by adjusting the combination of vibration stirring and jet stirring according to the shape and material of the workpiece.
[0041]
Further, from the results shown in FIG. 13 to FIG. 19, in Comparative Example 1 in which only jet stirring was performed, in Comparative Example 2 in which only vibration stirring was performed, and in Comparative Example 3 in which vibration stirring and jet stirring were performed simultaneously, It was confirmed that the hardness varies. From this, it can be seen that in order to ensure uniform hardness, both the vibration agitation and the jet agitation are performed on the coolant, and the operation order of the vibration agitation and the jet agitation is important. In addition, it was confirmed that variations in internal hardness were also caused in Example 3 and Example 4 in which the jet stirring was performed after the vibration stirring was performed for 12 seconds or more. From this, it can be seen that in order to ensure uniform hardness, the switching timing from stirring by vibration to stirring by jet is important.
[0042]
Furthermore, from the results shown in FIG. 20, the cooling state of the cooling liquid changes from the vapor film stage to the boiling stage approximately 4 seconds after the start of cooling, under any cooling conditions, It can be seen that about 10 seconds after the start of cooling, the boiling stage is changed to the convection stage. That is, in order to realize Example 1 and Example 2, the cooling state of the cooling liquid is in the vapor film stage (about 8 seconds from the start of cooling) in consideration of the time required for switching between vibration stirring and jet stirring. ), It is understood that vibration agitation is performed, and jet agitation is performed when the cooling state of the coolant is at an appropriate timing in the boiling stage and the convection stage.
[0043]
That is, from the above results, in Examples 1 and 2 in which the cooling process of the cooling liquid was stirred by vibration in the vapor film stage, and the cooling process of the cooling liquid was stirred by a jet in the boiling stage and the convection stage, distortion and bending, etc. It was confirmed that the quenching deformation having a uniform hardness was performed.
[0044]
【The invention's effect】
As described above, according to the quenching method of the present invention, a combination of vibration agitation and jet agitation is used to stir the cooling liquid that cools the workpiece by vibration and then agitation by the jet to quench. Sometimes the vapor film of the quenching oil formed on the surface of the object to be processed can be uniformly broken by vibration stirring, and the removed vapor can be diffused and disappeared uniformly by jet stirring. For this reason, it is possible to suppress variations in cooling capacity and to suppress quenching deformation such as distortion and bending of the workpiece that occurs during quenching.
According to the quenching apparatus of the present invention, the quenching method of the present invention can be easily realized.
[Brief description of the drawings]
FIG. 1 schematically shows an embodiment of a quenching apparatus according to the present invention, in which (a) is a front sectional view and (b) is a sectional view taken along the line bb in FIG. 1 (a).
FIG. 2 is a time chart showing one operating state of vibration stirring and jet stirring.
FIG. 3 is a time chart showing other operating states of vibration stirring and jet stirring.
FIG. 4 is a time chart showing other operating states of vibration stirring and jet stirring.
FIG. 5 is a time chart showing other operating states of vibration stirring and jet stirring.
FIG. 6 is a time chart showing an embodiment of operating states of vibration stirring and jet stirring with respect to the cooling time of the object to be processed.
FIG. 7 is a time chart showing another embodiment of operating states of vibration stirring and jet stirring with respect to the cooling time of the object to be processed.
FIG. 8 is a time chart showing another embodiment of operating states of vibration stirring and jet stirring with respect to the cooling time of an object to be processed.
FIG. 9 is a time chart showing another embodiment of operating states of vibration stirring and jet stirring with respect to the cooling time of the object to be processed.
FIG. 10 is a graph showing the relationship between the flow rate of a jet and the vibration frequency in vibration stirring.
FIG. 11 is a graph showing the relationship between the vibration frequency and the cooling rate in the present invention.
FIG. 12 is a graph showing the amount of distortion generated in the quenching method.
FIG. 13 is a graph showing the internal hardness when quenching is performed only by vibration stirring.
FIG. 14 is a graph showing the internal hardness when quenching is performed only by jet stirring.
FIG. 15 is a graph showing the internal hardness in a quenching method in which agitation stirring is performed after vibration stirring is performed for 4 seconds.
FIG. 16 is a graph showing the internal hardness in a quenching method in which agitation stirring is performed after vibration stirring is performed for 8 seconds.
FIG. 17 is a graph showing the internal hardness in a quenching method in which agitation stirring is performed after vibration stirring is performed for 12 seconds.
FIG. 18 is a graph showing the internal hardness in a quenching method in which agitation stirring is performed for 16 seconds and then jet stirring is performed.
FIG. 19 is a graph showing internal hardness in a quenching method in which vibration stirring and jet stirring are performed simultaneously.
FIG. 20 is a diagram showing the relationship between the cooling time of the object to be processed and the cooling state of the coolant.
FIG. 21 is a front sectional view schematically showing one embodiment of a conventional quenching apparatus.
[Explanation of symbols]
1 Coolant
2 Cooling tank
3 Propeller stirrer
4 Oscillatory flow (flow)
6 containers
10 Vibration stirrer (vibration stirring means)
20 Jet stirrer (jet stirrer)
30 Controller

Claims

  In the method of immersing the workpiece in the cooling liquid in the quenching cooling tank and quenching,
  Stirring the cooling liquid by vibration in the vapor film stage of the cooling liquid which is a cooling process immediately after immersion of the workpiece,
  When reaching the boiling stage of the coolant that is the next cooling process, the stirring of the coolant is switched from stirring by vibration to stirring by jet,
  A quenching method, wherein the cooling liquid is stirred only by a jet when it reaches the cooling liquid convection stage which is the next cooling process.

  In the method of immersing the workpiece in the cooling liquid in the quenching cooling tank and quenching,
  Stirring the cooling liquid by vibration in the vapor film stage of the cooling liquid which is a cooling process immediately after immersion of the workpiece,
  When the cooling liquid boiling stage, which is the next cooling process, is reached, the stirring of the cooling liquid is stirred by a jet together with stirring by vibration,
  A quenching method characterized by stopping stirring by vibration when the cooling liquid convection stage, which is the next cooling process, is reached, and stirring the cooling liquid only by a jet.

  In the method of immersing the workpiece in the cooling liquid in the quenching cooling tank and quenching,
  The cooling liquid is simultaneously stirred by vibration and a jet at the vapor film stage of the cooling liquid which is a cooling process immediately after immersion of the workpiece,
  When reaching the boiling stage of the cooling liquid, which is the next cooling process, only stirring by the vibration of the cooling liquid is stopped,
  A quenching method, wherein the cooling liquid is stirred only by a jet when it reaches the cooling liquid convection stage which is the next cooling process.

  In a quenching apparatus equipped with a quenching cooling tank in which a coolant for immersing and quenching the workpiece is stored,
  A vibration stirrer that stirs the cooling liquid by vibration; a jet stirrer that stirs the cooling liquid by a jet; and a controller that controls the vibration stirrer and the jet stirrer.
  The controller is
  The vibration stirrer is driven by vibration to stir the cooling liquid in the vapor film stage of the cooling liquid which is a cooling process immediately after immersion of the workpiece,
  When the boiling stage of the cooling liquid that is the next cooling process is reached, the vibration stirrer is stopped and the jet stirrer is driven to switch the stirring of the cooling liquid from stirring by vibration to stirring by jet.
  A quenching apparatus characterized in that when the cooling liquid convection stage, which is the next cooling process, is reached, the jet stirrer is driven so that the cooling liquid is stirred only by the jet flow.

  In a quenching apparatus equipped with a quenching cooling tank in which a coolant for immersing and quenching the workpiece is stored,
  A vibration stirrer that stirs the cooling liquid by vibration; a jet stirrer that stirs the cooling liquid by a jet; and a controller that controls the vibration stirrer and the jet stirrer.
  The controller is
  The vibration stirrer is driven by vibration in the vapor film stage of the cooling liquid which is a cooling process immediately after the immersion of the workpiece, and the cooling liquid is stirred by vibration,
  When the boiling stage of the coolant that is the next cooling process is reached, the jet stirrer is driven together with the vibration stirrer to stir the coolant by vibration and jet,
  When the cooling liquid convection stage, which is the next cooling process, is reached, the jet agitator is driven to A quenching apparatus, wherein the cooling liquid is controlled to be stirred only by a jet.

  In a quenching apparatus equipped with a quenching cooling tank in which a coolant for immersing and quenching the workpiece is stored,
  A vibration stirrer that stirs the cooling liquid by vibration; a jet stirrer that stirs the cooling liquid by a jet; and a controller that controls the vibration stirrer and the jet stirrer.
  The controller is
  The vibration stirrer and the jet flow stirrer are simultaneously driven at the vapor film stage of the cooling liquid which is the cooling process immediately after the immersion of the workpiece, and the cooling liquid is stirred by the vibration and the jet flow.
  When reaching the boiling stage of the cooling liquid which is the next cooling process, only the vibration stirrer is stopped,
  A quenching device characterized in that when the cooling liquid convection stage, which is the next cooling process, is reached, only the jet stirrer is continuously driven so that the cooling liquid is stirred only by the jet flow. .