JP3627650B2

JP3627650B2 - Ring rolling molding condition optimization method and apparatus

Info

Publication number: JP3627650B2
Application number: JP2000387211A
Authority: JP
Inventors: 欣弘平瀬; 孝有泉; 貞和升田
Original assignee: JFE Steel Corp
Current assignee: JFE Steel Corp
Priority date: 2000-12-20
Filing date: 2000-12-20
Publication date: 2005-03-09
Anticipated expiration: 2020-12-20
Also published as: JP2002178009A

Description

【０００１】
【発明の属する技術分野】
本発明は、リングローリング圧延を行うに際し、予めシミュレーションして成形条件を適正化する方法および装置に関する。
【０００２】
【従来の技術】
図６は一般的なリングローリング圧延機の構成を概略的に示すもので、（ａ）は一部断面表示を含む側面図、（ｂ）は平面図である。図において、１はリング状被圧延材（以下、単に被圧延材という）、２はメインロール、３はマンドレル、４はエッジャーロール（以下、単にエッジャーという）、５はトレーサである。
【０００３】
リングローリング圧延においては、トレーサ５により被圧延材１の径を検出しながら、被圧延材１をメインロール２とマンドレル３により半径方向の肉厚圧延を行い、上下の円錐形状エッジャー４，４により軸方向の高さ圧延を行う。メインロール２は、固定されており、一定速度で回転しながら圧延材１を一定外周速度で回転させる機能を有している。マンドレル３は、従動で、被圧延材１の内径側に配置され、メインロール２と共にリング状被圧延材１を挟み付け、メインロール方向に移動して肉厚方向の圧下を行うようになっている。
【０００４】
エッジャー４，４は、一般にメインロール２とは１８０度異なる位置において、円錐状のロールが上下に配置されて片方または両方が駆動され、通常、上ロールが下方に移動して被圧延材１に対し高さ方向の圧下を行うようになっている。エッジャー４，４を円錐形状としているのは、圧延対象である被圧延材１の周速が、その内周側と外周側で異なり（内周側＜外周側）、その周速差を吸収させる必要があるためである。従って、エッジャー４，４は、円錐状ロールの先端が被圧延材１の中心に一致するように配置され、被圧延材１の径の成長とともにロール周面における被圧延材１に対する圧下位置が水平方向（拡径側）に移動していくようになっている。
【０００５】
このようなリングローリング圧延機の制御方法については、例えば特開昭５４−１５５９７７号公報（以下、第１従来例という）や、特開昭５４−１６１５６０号公報（以下、第２従来例という）のものを挙げることができる。
【０００６】
第１従来例に示されている制御方法は、被圧延材の外径成長速度が、予め格納してある被圧延材の外径成長速度と一致するように制御するものである。
【０００７】
また、第２従来例に示されている制御方法は、被圧延材に対する半径方向の圧下工程を複数の工程から構成し、被圧延材の温度や半径方向寸法に基づいて圧下力を各工程の区間内で一定になるように制御するものである。
【０００８】
【発明が解決しようとする課題】
しかしながら、前述の第１及び第２従来例に記載されている手法では、いずれも被圧延材の最終形状に対する初期形状の設定の仕方や初期形状から最終形状へどのような経路でどのような時間で圧下するかの検証がされていない。
【０００９】
本発明者の実験によれば、被圧延材の成形状態には優劣があり、ひどい場合には図７に示すような被圧延材１の上下面へこみ（高さ方向へこみ）１ａ，１ｂや両側面へこみ（肉厚方向へこみ）１ｃ，１ｄが発生することが判明している。
【００１０】
本発明の技術的課題は、リング状被圧延材にへこみ等の形状不良が発生するのを未然に防止し得るようにすることにある。
【００１１】
【課題を解決するための手段】
本発明の請求項１に係るリングローリング成形条件適正化方法は、リング状被圧延材の外径寸法をトレーサロールにより検知しながら、被圧延材の半径方向の肉厚圧下を行うメインロール及びマンドレルと、被圧延材の軸方向の高さ圧下を行う上下一対のエッジャーロールとにより、被圧延材を目標とする外径、内径、高さとなるようにリングローリング圧延を行うに際し、予めシミュレーションして成形条件を適正化する方法であって、
ａ．前記被圧延材を複数のリング状弧要素に分割し、
ｂ．この時の分割数とリング状被圧延材の外径寸法とから前記各弧要素の初期弧長を算出し、
ｃ．算出した前記各弧要素の弧長と圧延速度とから、メインロール及びマンドレルによる各弧要素の肉厚方向圧延および上下エッジャーによる各弧要素の高さ方向圧延の時刻を、一方の弧要素が肉厚方向圧延を受ける時刻に他方の弧要素が高さ方向圧延を受けるように計算して求め、
ｄ．求めた時刻に、一方の弧要素の肉厚方向圧延による変形形状と、他方の弧要素の高さ方向圧延による変形形状とを、それぞれ計算して、各弧要素の圧延後の肉厚、高さ、弧長、へこみ量を算定し、
ｅ．得られた各弧要素の弧長を合計して被圧延材の周長を求め、その周長を円周率で除すことにより直径を求め、
ｆ．得られた直径値を基に、次の弧要素を圧延する時刻とマンドレル、エッジャーの圧下量を求め、
ｇ．得られた時刻および圧下量を基に、その時刻における圧延状態をシミュレートしていき、
ｈ．前記ｃ〜ｆの手順を順次繰り返すことにより、目標とする外径に達した時刻におけるリング状被圧延材のへこみ量を求め、
ｉ．前記ｃ〜ｇの手順をマンドレル、エッジャーの圧延条件および被圧延材の初期形状を変更して順次繰り返し行うことにより、へこみ量をより小さくできる圧延条件を導き出すことを特徴としている。
【００１２】
また、この方法に用いられる請求項２の装置は、リング状被圧延材の外径寸法をトレーサロールにより検知しながら、被圧延材の半径方向の肉厚圧下を行うメインロール及びマンドレルと、被圧延材の軸方向の高さ圧下を行う上下一対のエッジャーロールとにより、被圧延材を目標とする外径、内径、高さとなるようにリングローリング圧延を行うに際し、予めシミュレーションして成形条件を適正化する装置であって、
前記被圧延材を複数のリング状弧要素に分割する分割手段と、
この時の分割数とリング状被圧延材の外径寸法とから前記各弧要素の初期弧長を算出する初期弧長算出手段と、
前記各弧要素の初期弧長と圧延速度とから、メインロール及びマンドレルによる各弧要素の肉厚方向圧延および上下エッジャーによる各弧要素の高さ方向圧延の時刻を、一方の弧要素が肉厚方向圧延を受ける時刻に他方の弧要素が高さ方向圧延を受けるように算出する圧延時刻算出手段と、
前記圧延時刻算出手段が算出した各時刻に、一方の弧要素の肉厚方向圧延による肉厚、高さ、弧長、高さ方向へこみ量を算出する第１の変形形状算出手段と、
前記第１の変形形状算出手段による算出時刻と同時刻に、他方の弧要素の高さ方向圧延による肉厚、高さ、弧長、肉厚方向へこみ量を算出する第２の変形形状算出手段と、
前記第１及び第２の変形形状算出手段により得られた各弧要素の弧長を合計して被圧延材の周長を求める周長算出手段と、
前記周長算出手段により得られた被圧延材の周長を円周率で除すことにより直径を求める直径算出手段と、
得られた直径値と、前記分割数、前記圧延速度、及び圧延条件に基づき、次の弧要素を圧延する時刻までのマンドレル、エッジャーの圧下量を求める圧下量算出手段と、
前記直径算出手段の算出結果を設定値と比較することで目標外径か否かを判定する目標外径判定手段と、
前記第１及び第２の変形形状算出手段により得られた各弧要素のへこみ量をみて、目標とする外径に達した時刻におけるリング状被圧延材のへこみ量を判定するへこみ量判定手段と、
を有してなるものである。
【００１３】
【発明の実施の形態】
以下、本発明の実施形態に係るリングローリング成形条件適正化方法およびこの方法に用いられる装置を図１乃至図５に基づき説明する。図１は本実施形態に係るリングローリング成形条件適正化装置の構成を示すブロック図、図２はリング状被圧延材の分割例（１６分割）の説明図、図３は分割された弧要素の説明図、図４及び図５はリングローリング成形条件適正化方法を説明するためのフローチャートである。なお、説明にあたっては前述の図６及び図７を参照するものとする。
【００１４】
本実施形態のリングローリング成形条件適正化装置は、被圧延材１の外径寸法をトレーサロール５により検知しながら、被圧延材１の半径方向の肉厚圧下を行うメインロール２及びマンドレル３と、メインロール２とは１８０度異なる位置に配置されて被圧延材１の軸方向の高さ圧下を行う上下一対のエッジャーロール４，４とにより、被圧延材１を目標とする外径、内径、高さとなるようにリングローリング圧延を行うに際し、予めシミュレーションして成形条件を適正化するもので、図１の構成を有する。
【００１５】
すなわち、被圧延材１を、オペレータが入力した分割数に基づいて図２及び図３のように複数（ここでは１６分割）のリング状弧要素１Ａ，１Ｂ，１Ｃ，…１Ｐに分割する分割手段１１と、この時の分割数と被圧延材１の外径寸法とから前記各弧要素１Ａ，１Ｂ，１Ｃ，…１Ｐの初期弧長Ｌを算出する初期弧長算出手段１２と、圧延開始時に例えばメインロール２側に弧要素１Ａがあり、上下エッジャー４，４側に弧要素１Ｉがあるとした場合における各弧要素１Ａ，１Ｉの前記初期弧長Ｌとオペレータにより入力された圧延速度とから、メインロール２及びマンドレル３による弧要素１Ａの肉厚方向圧延および上下エッジャー４，４による弧要素１Ｉの高さ方向圧延の時刻を、一方の弧要素１Ａが肉厚方向圧延を受ける時刻に他方の弧要素１Ｉが高さ方向圧延を受けるように算出する圧延時刻算出手段１３と、圧延時刻算出手段１３が算出した各時刻に、オペレータにより予め入力された圧延条件または後述の圧下量算出手段より入力する圧下量に基づき、一方の弧要素１Ａの肉厚方向圧延による肉厚、高さ、弧長、高さ方向へこみ量を算出する第１の変形形状算出手段１４と、第１の変形形状算出手段１４による算出時刻と同時刻に、前記圧延条件または後述の圧下量算出手段より入力する圧下量に基づき、他方の弧要素１Ｉの高さ方向圧延による肉厚、高さ、弧長、肉厚方向へこみ量を算出する第２の変形形状算出手段１５と、を有する。
【００１６】
また、第１及び第２の変形形状算出手段１４，１５により得られた各弧要素１Ａ，１Ｉの弧長を含む１Ａ〜１Ｐまでの弧長を合計して、被圧延材１の周長を求める周長算出手段１６と、周長算出手段１６により得られた被圧延材１の周長を円周率πで除すことにより直径を求める直径算出手段１７と、得られた直径値と、前記分割数、前記圧延速度、及び前記圧延条件に基づき、次の弧要素を圧延する時刻までのマンドレル３、エッジャー４の圧下量を求める圧下量算出手段１８と、直径算出手段１７の算出結果を設定値と比較することで目標外径か否かを判定する目標外径判定手段１９と、第１及び第２の変形形状算出手段１４，１５により得られた各弧要素１Ａ，１Ｉのへこみ量、つまり図３および図７に示す高さＨ方向のへこみ１ａ，１ｂの量や肉厚Ｔ方向のへこみ１ｃ，１ｄの量をみて、目標とする外径に達した時刻におけるリング状被圧延材のへこみ量を判定するへこみ量判定手段２１と、各種の入力データやシミュレーションの経過（動画）および結果（弧要素形状等）を表示する表示手段２２と、プリンタ２３と、から構成され、マンドレル、エッジャーの圧延条件の値を変更してシミュレーションを順次繰り返し行うことにより、へこみ１ａ，１ｂ，１ｃ，１ｄの量をより小さくできる圧延条件を導き出すものである。
【００１７】
次に、本実施形態装置を用いてリングローリング成形条件を適正化する方法について、メインロール及びマンドレルと上下一対のエッジャーロールとが１８０度異なる位置に配置されているものとして、図４および図５に基づき図１乃至図３を参照しながら説明する。
【００１８】
まず、シミュレータを起動させるために、初期設定としてプレス形状データ（外径、内径、高さなど）、圧延速度、被圧延材分割数（ここでは１６分割）、を入力する（ステップ１）。次いで、圧延条件（マンドレル圧下条件、エッジャー圧下条件）を入力し（ステップ２）、シミュレータを起動させる。
【００１９】
シミュレータでは、まず被圧延材を１６のリング状弧要素に分割し（ステップ３）、この時の分割数（例えば１６分割）と被圧延材の外径寸法とから各弧要素の初期弧長Ｌを算出し（ステップ４）、次いで算出した各弧要素の弧長Ｌと圧延速度とから、メインロール及びマンドレルによる弧要素１Ａの肉厚方向圧延および上下エッジャーによる弧要素１Ｉの高さ方向圧延の時刻を、一方の弧要素１Ａが肉厚方向圧延を受ける時刻に他方の弧要素１Ｉが高さ方向圧延を受けるように計算して求める（ステップ５）。
【００２０】
圧延時刻が求まると、一方の弧要素１Ａの肉厚方向圧延による肉厚、高さ、弧長、高さ方向へこみ量が算出される（ステップ６）と同時に、他方の弧要素１Ｉの高さ方向圧延による肉厚、高さ、弧長、肉厚方向へこみ量が算出される（ステップ７）。
【００２１】
次に、算出された変形形状の中から各弧要素１Ａ，１Ｉの弧長が取り出され（ステップ８）、取り出された各弧要素１Ａ，１Ｉの弧長を含む１Ａ〜１Ｐまでの弧長が合計されて被圧延材の周長が算出され（ステップ９）、さらに被圧延材の直径が算出される（ステップ１０）。次いで、次の各弧要素１Ｂ，１Ｊの弧長と圧延速度とからこれら弧要素１Ｂ，１Ｊが圧延を終了する時刻が算出されるとともに（ステップ１１）、前記直径値と圧延条件とから次の弧要素１Ｂ，１Ｊが圧延された時刻までのマンドレル、エッジャーの圧下量が算出され（ステップ１２）、算出された時刻と圧下量が設定される（ステップ１３）。
【００２２】
次いで、被圧延材が目標外径となったか否かが判定され（ステップ１４）、目標外径でなければ、ステップ６，７に戻り、ステップ１３にて設定された時刻と圧下量に基づく次の一方の弧要素１Ｂの肉厚方向圧延による肉厚、高さ、弧長、高さ方向へこみ量、及び次の他方の弧要素１Ｊの高さ方向圧延による肉厚、高さ、弧長、肉厚方向へこみ量が算出される。
【００２３】
このようにして、得られた時刻および圧下量を基に、その時刻における圧延状態がシミュレートされ、ステップ６〜ステップ１４の手順が順次繰り返えされ、目標とする外径に達した時刻におけるリング状被圧延材のへこみ量が求められる。そして、ステップ１４にて被圧延材が目標外径となったと判定されると、へこみ量が許容範囲内であるか否かが判定され（ステップ１５）、許容範囲内でなければ、オペレータによりマンドレル、エッジャーの圧延条件および被圧延材の初期形状が変更され、ステップ２〜ステップ１５の手順が順次繰り返えされ、へこみ量をより小さくできる圧延条件が導き出される。
【００２４】
ところで、本実施形態のリングローリング成形条件適正化方法において、へこみ量ｄＢは、幅広がり量ｄＨの経験式を拡張して以下のような式を構築して求めた。
幅広がり量ｄＨ＝α・（ｌｄ／（Ｔ＋２Ｈ））・（ｄＴ／Ｔ）
へこみ量ｄＢ＝β・ｄＨ
Ｄ＝２＊（ＤＬ＊ＤＴ１＋（ｄＴ^２／４−ＤＴ１^２））／ｄＴ
ＤＴ１＝（ＤＳ＊ｄＴ−ｄＴ^２）／（ＤＬ＋ＤＳ−ｄＴ／２）
ここで、α，β：係数
ｌｄ：接触弧長（＝（Ｄ・ｄＴ／２）^０．５）
Ｔ：分割要素における肉厚
ｄＴ：肉厚圧下量
ｄＴ／Ｔ：肉厚圧下率
Ｄ：等価ロール径
Ｈ：分割要素における高さ
ＤＬ：メインロール直径
ＤＳ：マンドレル直径
この経験式における係数α、βを有限要素法解析（ＦＥＭ：ｆｉｎｉｔｅｅｌｅｍｅｎｔｍｅｔｈｏｄ）により求め、その結果を実験結果と比較し補正した。ここでは、α＝２．０、β＝５．０を用いた。
【００２５】
また、圧延時刻は以下のようにして求めた。
リングローリング成形においては、メインロールが一定速度で回転して圧延していく。ここで、メインロールの外周速度をＶ（ｍｍ／ｓ）とすると、ｎ番目の分割要素がメインロールとマンドレルにより肉厚圧延されるのに要する時間は、ｎ番目の分割要素における弧長をＬｎ（ｍｍ）とすると、
Δｎ＝Ｌｎ／Ｖ（ｓｅｃ）
よって１番目の分割要素の圧延開始時刻を０とすると、終了時刻はΔＴ１、２番目の分割要素の圧延終了時刻はΔＴ１＋ΔＴ２というように求められる。なお、解析の上では、各分割要素は圧延される毎に弧長が変化しているので、その変化を考慮して各圧延時刻毎の変形を追跡した。
【００２６】
本発明のリングローリング成形条件適正化方法による成形条件適正化の結果を下表１に示す。
【００２７】
【表１】

【００２８】
表１の成形条件適正化の結果求めた成形条件として、リングローリング前の素材形状として外径５４１．３ｍｍ、内径１４０ｍｍ、高さ１３５ｍｍを選定し、外径５４１．３ｍｍから１４３０ｍｍまでの成形初期、中期においては外径成長速度を６ｍｍ／ｓｅｃになるように直線的に制御し、外径が１４３０ｍｍから１４５０ｍｍまでの終期には外径成長速度が１．５ｍｍ／ｓｅｃになるように制御し、かつ外径が５４１．３ｍｍ時の高さ１３５ｍｍから外径１４５０ｍｍ時の高さ８４ｍｍまでを２次曲線的に制御した。２次曲線的な制御としては、以下の手法を用いた。
Ｈ＝Ｃ１／Ｄｗ^ｎ＋Ｃ２
ここで、Ｈ：分割要素における高さ
Ｃ１，Ｃ２：係数
ｎ：次数
このケースではｎ＝２（２次）で、この２次曲線が初期外径Ｄｗが
Ｄｗ＝５４１．３ｍｍの時にＨ＝１３５ｍｍ
初期外径Ｄｗが
Ｄｗ＝１４５０ｍｍの時にＨ＝８４ｍｍ
を満たすように係数Ｃ１，Ｃ２を決定し、この曲線にしたがって高さを制御した。
【００２９】
本発明による実施結果を、従来の圧力一定制御による成形品および従来の外径成長速度制御による成形品と比較して下表２に示す。
【００３０】
【表２】

【００３１】
表２において、使用した鋼種はＳ４８Ｃで、最終製品形状は外径１４５０ｍｍ、内径１２９０ｍｍ、高さ８４ｍｍである。従来の圧力一定制御では、リングローリング前の素材形状として外径５７２ｍｍ、内径１４０ｍｍ、高さ１２０ｍｍを用い、圧力が６５ｋｇ／ｃｍ^２一定になるように制御し、トレーサ検知の外径が１４５０ｍｍになった時点で終了した。また、従来の外径成長速度制御では、リングローリング前の素材形状として外径５７２ｍｍ、内径１４０ｍｍ、高さ１２０ｍｍを用い、外径が５７２ｍｍから１４３０ｍｍまでは外径成長速度が７ｍｍ／ｓｅｃになるように制御し、外径が１４３０ｍｍから１４５０ｍｍまでは外径成長速度が１．５ｍｍ／ｓｅｃになるように制御し、かつリング状被圧延材の高さを外径に対する位置制御した。外径５７２ｍｍ時の初期高さ１２０ｍｍから外径１４５０ｍｍ時の高さ８４ｍｍまで直線的に高さを外径に対して制御した。
【００３２】
表２から明らかなように、本発明は寸法精度が良く、かつへこみがなく、従来方式に比べ優れていた。
【００３３】
【発明の効果】
以上述べたように、本発明の請求項１のリングローリング成形条件適正化方法およびこの方法に用いられる請求項２の装置によれば、適正な成形条件を試圧延を数多く行うことなく見出すことができ、試圧延の時間、材料費を省略できた。また、適正化された成形条件で圧延したリングローリング成形品は、寸法精度が良く、かつ表面のへこみがないため、成形品の仕上げ工程を省略でき、製品の歩留り、生産性が向上した。
【図面の簡単な説明】
【図１】本発明の一実施形態に係るリングローリング成形条件適正化装置の構成を示すブロック図である。
【図２】リング状被圧延材の分割例（１６分割）の説明図である。
【図３】分割された弧要素の説明図である。
【図４】本発明のリングローリング成形条件適正化方法を説明するためのフローチャートである。
【図５】本発明のリングローリング成形条件適正化方法を説明するためのフローチャートである。
【図６】一般的なリングローリング圧延機の概略構成図である。
【図７】従来手法による問題点（へこみ発生）の説明図である。
【符号の説明】
１リング状被圧延材
１Ａ〜１Ｐリング状弧要素
１ａ，１ｂ高さ方向へこみ
１ｃ，１ｄ肉厚方向へこみ
２メインロール
３マンドレル
４エッジャーロール
５トレーサロール
１１リング状被圧延材分割手段
１２初期弧長算出手段
１３圧延時刻算出手段
１４第１の変形形状算出手段
１５第２の変形形状算出手段
１６周長算出手段
１７直径算出手段
１８圧下量算出手段
１９目標外径判定手段
２１へこみ量判定手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for optimizing molding conditions by performing simulation in advance when performing ring rolling rolling.
[0002]
[Prior art]
FIG. 6 schematically shows a configuration of a general ring rolling mill, in which (a) is a side view including a partial cross-sectional display, and (b) is a plan view. In the figure, 1 is a ring-shaped rolled material (hereinafter simply referred to as a rolled material), 2 is a main roll, 3 is a mandrel, 4 is an edger roll (hereinafter simply referred to as an edger), and 5 is a tracer.
[0003]
In the ring rolling rolling, while the diameter of the material 1 to be rolled is detected by the tracer 5, the material 1 is rolled in the radial direction by the main roll 2 and the mandrel 3, and the upper and lower

conical edgers

4 and 4 are used. Axial height rolling is performed. The main roll 2 is fixed and has a function of rotating the rolled material 1 at a constant outer peripheral speed while rotating at a constant speed. The mandrel 3 is driven and arranged on the inner diameter side of the material 1 to be rolled, sandwiches the ring-shaped material 1 together with the main roll 2, moves in the main roll direction, and performs reduction in the thickness direction. Yes.
[0004]
In the

edgers

4 and 4, generally, at a position different from the main roll 2 by 180 degrees, conical rolls are arranged one above the other and one or both are driven, and usually the upper roll moves downward to the material 1 to be rolled. On the other hand, a reduction in the height direction is performed. The

edgers

4 and 4 have a conical shape because the peripheral speed of the material 1 to be rolled is different between the inner peripheral side and the outer peripheral side (inner peripheral side <outer peripheral side), and the peripheral speed difference is absorbed. This is necessary. Therefore, the

edgers

4 and 4 are disposed so that the tip of the conical roll coincides with the center of the material 1 to be rolled, and the rolling position with respect to the material 1 to be rolled on the roll peripheral surface is horizontal as the diameter of the material 1 to be rolled grows. It moves in the direction (expanded side).
[0005]
As for the control method of such a ring rolling mill, for example, Japanese Patent Laid-Open No. 54-155777 (hereinafter referred to as a first conventional example) and Japanese Patent Laid-Open No. 54-161560 (hereinafter referred to as a second conventional example). Can be mentioned.
[0006]
The control method shown in the first conventional example is to control the outer diameter growth rate of the material to be rolled so as to coincide with the outer diameter growth rate of the material to be rolled that has been stored in advance.
[0007]
Further, the control method shown in the second conventional example comprises a plurality of radial reduction steps for the material to be rolled, and the reduction force of each step is determined based on the temperature and radial dimensions of the material to be rolled. It is controlled so as to be constant within the section.
[0008]
[Problems to be solved by the invention]
However, in the methods described in the first and second conventional examples, the initial shape is set with respect to the final shape of the material to be rolled, and the route from the initial shape to the final shape and what time and what time. It has not been verified whether or not it is rolled down.
[0009]
According to the experiment of the present inventor, the shape of the material to be rolled is superior or inferior, and in a severe case, the material to be rolled 1 is dented (indented in the height direction) 1a, 1b or both sides as shown in FIG. It has been found that surface dents (thickness direction dents) 1c and 1d occur.
[0010]
The technical problem of the present invention is to prevent the occurrence of shape defects such as dents in the ring-shaped rolled material.
[0011]
[Means for Solving the Problems]
The ring rolling forming condition optimizing method according to claim 1 of the present invention includes a main roll and a mandrel that perform thickness reduction in the radial direction of the material to be rolled while detecting the outer diameter of the ring-shaped material to be rolled by the tracer roll. And a pair of upper and lower edger rolls that reduce the height of the material to be rolled in the axial direction, a ring roll rolling is performed in advance so that the material to be rolled has a target outer diameter, inner diameter, and height. A method for optimizing molding conditions,
a. Dividing the material to be rolled into a plurality of ring-shaped arc elements;
b. Calculate the initial arc length of each arc element from the number of divisions at this time and the outer diameter of the ring-shaped rolled material,
c. From the calculated arc length and rolling speed of each arc element, the thickness direction rolling of each arc element by the main roll and mandrel and the height direction rolling of each arc element by the upper and lower edgers are used. Calculated so that the other arc element undergoes height direction rolling at the time of undergoing thickness direction rolling,
d. At the obtained time, the deformation shape by rolling in the thickness direction of one arc element and the deformation shape by rolling in the height direction of the other arc element are respectively calculated, and the thickness and height after rolling of each arc element are calculated. Calculate arc length, dent amount,
e. Obtain the perimeter of the material to be rolled by totaling the arc length of each arc element obtained, and obtain the diameter by dividing the perimeter by the circumference,
f. Based on the obtained diameter value, the time to roll the next arc element and the mandrel, the amount of reduction of the edger,
g. Based on the obtained time and reduction amount, we simulated the rolling state at that time,
h. By sequentially repeating the steps c to f, the amount of dent of the ring-shaped rolled material at the time when the target outer diameter is reached is obtained,
i. It is characterized by deriving rolling conditions that can further reduce the amount of dents by sequentially repeating the steps c to g while changing the mandrel and edger rolling conditions and the initial shape of the material to be rolled.
[0012]
Further, the apparatus of claim 2 used in this method includes a main roll and a mandrel that perform thickness reduction in the radial direction of the material to be rolled while detecting the outer diameter of the ring-shaped material to be rolled by the tracer roll, When performing ring rolling rolling to achieve the target outer diameter, inner diameter, and height of the material to be rolled with a pair of upper and lower edger rolls that reduce the height of the rolled material in the axial direction, forming conditions are simulated in advance. Is a device that optimizes
A dividing means for dividing the material to be rolled into a plurality of ring-shaped arc elements;
Initial arc length calculation means for calculating the initial arc length of each arc element from the number of divisions at this time and the outer diameter dimension of the ring-shaped rolled material,
From the initial arc length and rolling speed of each arc element, the time of the thickness direction rolling of each arc element by the main roll and the mandrel and the height direction rolling of each arc element by the upper and lower edgers, one arc element is the thickness Rolling time calculation means for calculating the other arc element to receive height direction rolling at the time of receiving direction rolling;
At each time calculated by the rolling time calculating means, a first deformed shape calculating means for calculating a thickness, height, arc length, and dent amount in the height direction by rolling in the thickness direction of one arc element;
Second deformation shape calculation means for calculating the thickness, height, arc length, and dent amount in the thickness direction due to height direction rolling of the other arc element at the same time as the calculation time by the first deformation shape calculation means. When,
A circumference calculating means for calculating the circumference of the material to be rolled by summing the arc lengths of the respective arc elements obtained by the first and second deformed shape calculating means,
Diameter calculation means for obtaining a diameter by dividing the circumference of the material to be rolled obtained by the circumference calculation means by the circumference, and
Based on the obtained diameter value, the number of divisions, the rolling speed, and rolling conditions, a mandrel up to the time of rolling the next arc element, a rolling amount calculation means for obtaining a rolling amount of the edger,
Target outer diameter determining means for determining whether or not the target outer diameter by comparing the calculation result of the diameter calculating means with a set value;
A dent amount judging means for judging the dent amount of the ring-shaped rolled material at the time when the target outer diameter is reached by looking at the dent amount of each arc element obtained by the first and second deformed shape calculating means; ,
Is provided.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a method for optimizing ring rolling molding conditions and an apparatus used in the method according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing the configuration of a ring rolling forming condition optimizing apparatus according to the present embodiment, FIG. 2 is an explanatory diagram of a division example (16 divisions) of a ring-shaped rolled material, and FIG. 3 is an illustration of divided arc elements FIG. 4 and FIG. 5 are flowcharts for explaining a method for optimizing ring rolling molding conditions. In the description, reference is made to FIG. 6 and FIG.
[0014]
The ring rolling molding condition optimizing device of the present embodiment includes a main roll 2 and a mandrel 3 that perform wall thickness reduction in the radial direction of the material 1 while the outer diameter of the material 1 is detected by the tracer roll 5. The outer diameter targeted for the material 1 to be rolled by the pair of upper and lower edger rolls 4, 4 arranged at a position 180 degrees different from the main roll 2 and performing the axial height reduction of the material 1 to be rolled. When performing ring rolling rolling so as to have an inner diameter and a height, simulation is performed in advance to optimize the molding conditions, and the configuration shown in FIG. 1 is provided.
[0015]
That is, the dividing means for dividing the material 1 to be rolled into a plurality (here, 16 divisions) of ring-shaped

arc elements

1A, 1B, 1C,... 1P as shown in FIGS. 11 and the initial arc length calculating means 12 for calculating the initial arc length L of each

arc element

1A, 1B, 1C,... 1P from the number of divisions at this time and the outer diameter dimension of the material 1 to be rolled, For example, when the arc element 1A is provided on the main roll 2 side and the arc element 1I is provided on the upper and

lower edgers

4 and 4, the initial arc length L of each arc element 1A, 1I and the rolling speed input by the operator. The time of the thickness direction rolling of the arc element 1A by the main roll 2 and the mandrel 3 and the time of the height direction rolling of the arc element 1I by the upper and

lower edgers

4, 4 are the same as the time when one arc element 1A receives the thickness direction rolling. Arc elements Rolling time calculation means 13 for calculating I so as to undergo height direction rolling, and rolling conditions previously input by the operator or rolling reduction input described later, at each time calculated by rolling time calculation means 13 Based on the amount, first deformed shape calculating means 14 for calculating the thickness, height, arc length, and dent amount in the height direction by rolling in the thickness direction of one arc element 1A, and first deformed shape calculating means 14 The thickness, height, arc length, and wall thickness indented in the height direction rolling of the other arc element 1I based on the rolling conditions or the amount of reduction input from the reduction amount calculation means described later at the same time Second deformation shape calculation means 15 for calculating the amount.
[0016]
Moreover, the arc length of 1A-1P including the arc length of each arc element 1A, 1I obtained by the 1st and 2nd deformation shape calculation means 14 and 15 is totaled, and the perimeter of the material 1 to be rolled is obtained. The required circumference calculating means 16, the diameter calculating means 17 for obtaining the diameter by dividing the circumference of the material 1 to be rolled obtained by the circumference calculating means 16 by the circumference ratio π, and the obtained diameter value, Based on the number of divisions, the rolling speed, and the rolling conditions, the rolling amount calculation means 18 for obtaining the rolling amount of the mandrel 3 and the edger 4 until the time of rolling the next arc element, and the calculation result of the diameter calculation means 17 are calculated. Depression amount of each arc element 1A, 1I obtained by the target outer diameter determining means 19 for determining whether or not the target outer diameter is compared with the set value, and the first and second deformed shape calculating means 14, 15 That is, the indentation 1a in the height H direction shown in FIGS. The amount of b and the amount of dents 1c and 1d in the thickness T direction are used to determine the amount of dent of the ring-shaped rolled material at the time when the target outer diameter is reached, and various input data And display means 22 for displaying the progress (movie) and results (arc element shape, etc.) of the simulation and the printer 23, and by changing the values of the rolling conditions of the mandrel and edger and repeating the simulation sequentially. The rolling conditions that can reduce the amounts of the dents 1a, 1b, 1c, and 1d are derived.
[0017]
Next, regarding the method for optimizing the ring rolling molding conditions using the apparatus of the present embodiment, it is assumed that the main roll and the mandrel and the pair of upper and lower edger rolls are arranged at positions different from each other by 180 degrees. 5 will be described with reference to FIGS.
[0018]
First, in order to activate the simulator, press shape data (outer diameter, inner diameter, height, etc.), rolling speed, and the number of parts to be rolled (here, 16 divisions) are input as initial settings (step 1). Next, rolling conditions (mandrel reduction conditions, edger reduction conditions) are input (step 2), and the simulator is activated.
[0019]
In the simulator, first, the material to be rolled is divided into 16 ring-shaped arc elements (step 3), and the initial arc length L of each arc element is determined from the number of divisions (for example, 16 divisions) and the outer diameter of the material to be rolled. (Step 4), and from the calculated arc length L and rolling speed of each arc element, the thickness direction rolling of the arc element 1A by the main roll and mandrel and the height direction rolling of the arc element 1I by the upper and lower edgers The time is calculated and calculated so that one arc element 1A undergoes thickness direction rolling and the other arc element 1I undergoes height direction rolling (step 5).
[0020]
When the rolling time is obtained, the thickness, height, arc length, and dent amount in the height direction of one arc element 1A by rolling in the thickness direction are calculated (step 6), and at the same time, the height of the other arc element 1I is calculated. Thickness, height, arc length, and dent amount in the thickness direction due to directional rolling are calculated (step 7).
[0021]
Next, the arc length of each arc element 1A, 1I is extracted from the calculated deformed shape (step 8), and the arc length from 1A to 1P including the arc length of each arc element 1A, 1I extracted is The circumference of the material to be rolled is calculated (step 9), and the diameter of the material to be rolled is further calculated (step 10). Next, the time at which these arc elements 1B and 1J end rolling is calculated from the arc length and rolling speed of each of the following arc elements 1B and 1J (step 11), and the next value is calculated from the diameter value and rolling conditions. The mandrel and edger reduction amounts up to the time when the arc elements 1B and 1J are rolled are calculated (step 12), and the calculated time and reduction amount are set (step 13).
[0022]
Next, it is determined whether or not the material to be rolled has a target outer diameter (step 14). If the target outer diameter is not the target outer diameter, the process returns to

steps

6 and 7, and the next based on the time set in step 13 and the amount of reduction. Thickness, height, arc length, amount of indentation in the height direction of one arc element 1B, and thickness, height, arc length of the other arc element 1J in height direction rolling, The amount of dent in the thickness direction is calculated.
[0023]
In this way, based on the obtained time and the amount of reduction, the rolling state at that time is simulated, and the procedures of Step 6 to Step 14 are sequentially repeated, and at the time when the target outer diameter is reached. The amount of dents in the ring-shaped rolled material is required. If it is determined in step 14 that the material to be rolled has reached the target outer diameter, it is determined whether or not the dent amount is within an allowable range (step 15). The rolling conditions of the edger and the initial shape of the material to be rolled are changed, and the procedure from step 2 to step 15 is sequentially repeated to derive the rolling conditions that can further reduce the amount of dents.
[0024]
By the way, in the ring rolling molding condition optimization method of the present embodiment, the dent amount dB is obtained by expanding the empirical formula of the width spread amount dH and constructing the following formula.
Widening amount dH = α · (ld / (T + 2H)) · (dT / T)
Depression amount dB = β · dH
D = 2 * (DL * DT1 + (dT ² / 4−DT1 ² )) / dT
DT1 = (DS * dT−dT ² ) / (DL + DS−dT / 2)
Where α, β: coefficient ld: contact arc length (= (D · dT / 2) ^0.5 )
T: Wall thickness dT: thickness reduction amount dT / T: Wall thickness reduction ratio D: Equivalent roll diameter H: Height of division element DL: Main roll diameter DS: Mandrel diameter Coefficient α, β in this empirical formula Was obtained by a finite element method analysis (FEM) and the result was compared with the experimental result and corrected. Here, α = 2.0 and β = 5.0 were used.
[0025]
Moreover, the rolling time was calculated | required as follows.
In ring rolling molding, the main roll rotates at a constant speed and is rolled. Here, when the outer peripheral speed of the main roll is V (mm / s), the time required for the n-th division element to be thick-rolled by the main roll and the mandrel is the length of the arc in the n-th division element as Ln. (Mm)
Δn = Ln / V (sec)
Therefore, when the rolling start time of the first division element is 0, the end time is obtained as ΔT1, and the rolling end time of the second division element is obtained as ΔT1 + ΔT2. In the analysis, the arc length of each divided element changes every time it is rolled, and the deformation at each rolling time is traced in consideration of the change.
[0026]
The results of optimization of the molding conditions by the ring rolling molding condition optimization method of the present invention are shown in Table 1 below.
[0027]
[Table 1]

[0028]
As molding conditions obtained as a result of optimization of molding conditions in Table 1, an outer diameter of 541.3 mm, an inner diameter of 140 mm, and a height of 135 mm are selected as a material shape before ring rolling, and an initial molding from an outer diameter of 541.3 mm to 1430 mm, In the middle period, the outer diameter growth rate is linearly controlled to be 6 mm / sec, and in the final period from 1430 mm to 1450 mm, the outer diameter growth rate is controlled to be 1.5 mm / sec. The height from 135 mm when the outer diameter was 541.3 mm to 84 mm when the outer diameter was 1450 mm was controlled in a quadratic curve. As a quadratic curve control, the following method was used.
H = C1 / Dw ⁿ + C2
Here, H: Height C1, C2 in the division element: Coefficient n: Order In this case, n = 2 (second order), and when this quadratic curve has an initial outer diameter Dw of Dw = 541.3 mm, H = 135 mm
H = 84mm when initial outer diameter Dw is Dw = 1450mm
The coefficients C1 and C2 were determined so as to satisfy the above, and the height was controlled according to this curve.
[0029]
The results of implementation according to the present invention are shown in Table 2 below in comparison with a conventional molded product with constant pressure control and a conventional molded product with outer diameter growth rate control.
[0030]
[Table 2]

[0031]
In Table 2, the steel type used is S48C, and the final product shape is an outer diameter of 1450 mm, an inner diameter of 1290 mm, and a height of 84 mm. In the conventional constant pressure control, an outer diameter of 572 mm, an inner diameter of 140 mm, and a height of 120 mm are used as the material shape before ring rolling, and the pressure is controlled to be constant at 65 kg / cm ² , and the outer diameter of the tracer detection becomes 1450 mm. It was finished at the time. Further, in the conventional outer diameter growth rate control, an outer diameter of 572 mm, an inner diameter of 140 mm, and a height of 120 mm are used as the material shape before ring rolling, and the outer diameter growth rate is 7 mm / sec from 572 mm to 1430 mm. The outer diameter growth rate was controlled to 1.5 mm / sec when the outer diameter was from 1430 mm to 1450 mm, and the height of the ring-shaped rolled material was controlled relative to the outer diameter. The height was linearly controlled from the initial height of 120 mm when the outer diameter was 572 mm to the height of 84 mm when the outer diameter was 1450 mm.
[0032]
As is apparent from Table 2, the present invention has a good dimensional accuracy and no dent, and is superior to the conventional method.
[0033]
【The invention's effect】
As described above, according to the method for optimizing the ring rolling forming condition of claim 1 of the present invention and the apparatus of claim 2 used in this method, it is possible to find an appropriate forming condition without performing many trial rollings. The test rolling time and material cost could be omitted. In addition, a ring rolling molded product rolled under optimized molding conditions has good dimensional accuracy and no surface dents, so that the finishing process of the molded product can be omitted, and the product yield and productivity are improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a ring rolling molding condition optimization device according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram of a division example (16 divisions) of a ring-shaped rolled material.
FIG. 3 is an explanatory diagram of divided arc elements.
FIG. 4 is a flowchart for explaining a method for optimizing ring rolling molding conditions according to the present invention.
FIG. 5 is a flowchart for explaining a method for optimizing ring rolling molding conditions according to the present invention.
FIG. 6 is a schematic configuration diagram of a general ring rolling mill.
FIG. 7 is an explanatory diagram of problems (depression occurrence) caused by a conventional method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ring-shaped rolled material 1A-1P Ring-shaped arc element 1a, 1b Height direction dent 1c, 1d Thickness direction dent 2 Main roll 3 Mandrel 4 Edger roll 5 Tracer roll 11 Ring-shaped rolled material dividing means 12 Initial arc Length calculating means 13 Rolling time calculating means 14 First deformed shape calculating means 15 Second deformed shape calculating means 16 Perimeter length calculating means 17 Diameter calculating means 18 Reduction amount calculating means 19 Target outer diameter determining means 21 Indentation amount determining means

Claims

While detecting the outer diameter dimension of the ring-shaped rolled material with the tracer roll, the main roll and mandrel that perform the thickness reduction in the radial direction of the rolled material, and the upper and lower that perform the height reduction in the axial direction of the rolled material When performing ring rolling rolling so that the material to be rolled has a target outer diameter, inner diameter, and height with a pair of edger rolls, a method of optimizing molding conditions by performing simulation in advance,
a. Dividing the material to be rolled into a plurality of ring-shaped arc elements;
b. Calculate the initial arc length of each arc element from the number of divisions at this time and the outer diameter of the ring-shaped rolled material,
c. From the calculated arc length and rolling speed of each arc element, the thickness direction rolling of each arc element by the main roll and mandrel and the height direction rolling of each arc element by the upper and lower edgers are used. Calculated so that the other arc element undergoes height direction rolling at the time of undergoing thickness direction rolling,
d. At the obtained time, the deformation shape by rolling in the thickness direction of one arc element and the deformation shape by rolling in the height direction of the other arc element are respectively calculated, and the thickness and height after rolling of each arc element are calculated. Calculate arc length, dent amount,
e. Obtain the perimeter of the material to be rolled by totaling the arc length of each arc element obtained, and obtain the diameter by dividing the perimeter by the circumference,
f. Based on the obtained diameter value, the time to roll the next arc element and the mandrel, the amount of reduction of the edger,
g. Based on the obtained time and reduction amount, we simulated the rolling state at that time,
h. By sequentially repeating the steps c to f, the amount of dent of the ring-shaped rolled material at the time when the target outer diameter is reached is obtained,
i. Appropriate ring rolling forming conditions characterized by deriving rolling conditions that can reduce the amount of dents by sequentially repeating the steps c to g by changing the rolling conditions of the mandrel and edger and the initial shape of the material to be rolled. Method.

While detecting the outer diameter dimension of the ring-shaped rolled material with the tracer roll, the main roll and mandrel that perform the thickness reduction in the radial direction of the rolled material, and the upper and lower that perform the height reduction in the axial direction of the rolled material When performing ring rolling rolling so that the material to be rolled has a target outer diameter, inner diameter, and height with a pair of edger rolls, an apparatus that simulates in advance and optimizes the molding conditions,
A dividing means for dividing the material to be rolled into a plurality of ring-shaped arc elements;
Initial arc length calculation means for calculating the initial arc length of each arc element from the number of divisions at this time and the outer diameter dimension of the ring-shaped rolled material,
From the arc length and rolling speed of each arc element, the thickness direction rolling of each arc element by the main roll and mandrel and the height direction rolling of each arc element by the upper and lower edgers, one arc element in the thickness direction Rolling time calculating means for calculating the other arc element to receive height direction rolling at the time of receiving rolling;
At each time calculated by the rolling time calculating means, a first deformed shape calculating means for calculating the thickness, height, arc length, and dent amount in the height direction by rolling in the thickness direction of one arc element;
Second deformation shape calculation means for calculating the thickness, height, arc length, and dent amount in the thickness direction due to height direction rolling of the other arc element at the same time as the calculation time by the first deformation shape calculation means. When,
A circumference calculating means for calculating the circumference of the material to be rolled by summing the arc lengths of the respective arc elements obtained by the first and second deformed shape calculating means,
Diameter calculation means for obtaining a diameter by dividing the circumference of the material to be rolled obtained by the circumference calculation means by the circumference, and
Based on the obtained diameter value, the number of divisions, the rolling speed, and rolling conditions, a mandrel up to the time of rolling the next arc element, a rolling amount calculation means for obtaining a rolling amount of the edger,
Target outer diameter determining means for determining whether or not the target outer diameter by comparing the calculation result of the diameter calculating means with a set value;
A dent amount judging means for judging the dent amount of the ring-shaped rolled material at a time when the target outer diameter is reached by looking at the dent amount of each arc element obtained by the first and second deformed shape calculating means; ,
An apparatus for optimizing ring rolling molding conditions, comprising: