JP4360721B2

JP4360721B2 - Ring material straightening method

Info

Publication number: JP4360721B2
Application number: JP33198099A
Authority: JP
Inventors: 康男渡辺; 次夫皆川; 忠伸宮川
Original assignee: Dai Ichi High Frequency Co Ltd
Current assignee: Dai Ichi High Frequency Co Ltd
Priority date: 1999-11-22
Filing date: 1999-11-22
Publication date: 2009-11-11
Anticipated expiration: 2019-11-22
Also published as: JP2001150026A

Description

【０００１】
【発明の属する技術分野】
本発明は、直径方向に扁平化したリング材を真円に近づけるように矯正する方法に関する。
【０００２】
【従来の技術】
最近、直径が１〜３ｍに及ぶ大径のリング材の外周面、内周面又は端面に、耐摩耗性等の物性を向上させるために硬質の金属被覆層を形成した構成のリング材が要求されてきた。そこで、本発明者等は、この構成のリング材の製造方法として、まず、鋼製の所定形状のリング材を製造し、そのリング材の外周面、内周面又は端面に、自溶性合金等の金属被覆層形成用の材料を溶射して溶射層を形成し、次いで、その溶射層を加熱、溶融処理することで緻密な組織の金属被覆層を形成する方法を開発した。
【０００３】
【発明が解決しようとする課題】
ところが、この方法で製造したリング材は、微小ではあるが直径方向に扁平化して楕円化していることがあり、例えば、外径２０００ｍｍのリング材において、外径の最大値と最小値の差が１０ｍｍを越えるような扁平が生じることもあった。リング材の外周面又は内周面に形成する金属被覆層は、通常その厚みを２〜５ｍｍ程度としているため、金属被覆層の表面を研削して真円に仕上げようとした時に、上記扁平に起因して一部領域では金属被覆層を全部削り取ってしまうことがあり、良品歩留りを高位に確保しにくくコスト高につながっている。そこで、リング材の扁平を矯正して真円に近づける必要が生じてきた。
【０００４】
本発明はかかる要望に基づいてなされたもので、大径のリング材の扁平を矯正して真円に近づけることの可能なリング材の矯正方法を提供することを目的とする。
【０００５】
【課題を解決するための手段】
【０００６】
本発明の矯正方法は、矯正すべきリング材の内周面側に矯正治具を装着し且つその矯正治具の外形を前記リング材を変形させながら所定形状に設定し、その状態で前記リング材を加熱し次いでそのリング材を冷却してそのリング材に前記矯正治具を締め付けるたが張り力を発生させ、これにより前記リング材を前記矯正治具の外形に倣う形状に拘束してリング材の扁平を矯正する構成としたものである。この構成により、矯正治具の外形設定時に変形させられたリング材の残留応力が加熱で緩和され、その後の冷却でリング材を矯正治具の外形に倣う形状に変形させて拘束でき、これによってリング材を矯正治具から外した後においてもリング材を元の扁平形状よりも矯正治具の外形に近づく形状に矯正でき、従って、矯正治具の外形を適正に設定しておくことで、リング材を矯正治具から外した後においてリング材が所望の真円度になるように矯正することができる。
【０００８】
【発明の実施の形態】
本発明方法で矯正の対象とするリング材は、全体的に中空円筒状をなすものであれば任意であり、代表的なものとしては、図６、図７に示すような、内周面及び外周面を共に単純な円筒状とした母材２の外周面に母材の物性向上のための金属被覆層３を形成したリング材１、或いは母材２の内周面に金属被覆層を形成したもの等を挙げることができる。この構成のリング材は、金属被覆層の溶融処理時の加熱によって微小量ではあるが扁平化して楕円状となることが多く、その後、金属被覆層の表面を真円状に研削加工する必要があることから、研削加工に先立って扁平を矯正して真円に近づけることが必要であり、本発明適用の効果が大きい。
【０００９】
なお、矯正対象のリング材はこの構造に限らず、母材２の外周面、内周面、端面等に溝や段差を設けるとか、フランジを形成する等の変更を施したものでもよいし、また、金属被覆層の形成位置も適宜変更可能であり、更には、金属被覆層を備えていない構成のものでもよい。リング材を構成する母材は、金属材料であれば任意であり、具体的には、炭素鋼、低合金鋼、ステンレス鋼、鋳鋼、鋳鉄、Ｎｉ基合金、Ｃｕ基合金、Ａｌ基合金等を挙げることができる。また、金属被覆層も母材の物性を所望に応じて向上させ得る材料であれば任意であり、例えば、Ｎｉ基合金、Ｃｏ基合金、或いはこれらにＷＣ、Ｃｒ₃ Ｃ₂ 、ＴｉＢ₂ 等の硬質材微粒子を配合したもの等を挙げることができる。リング材の寸法も特に限定されるものではないが、径の大きいもの、例えば外径が１〜３ｍといった大径のものが、扁平量（＝最大径−最小径）が大きくなって金属被覆層の厚さを越えてしまい、扁平矯正の必要性が高いので、本発明方法を適用するメリットが大きい。
【００１０】
以下、本発明の参考例及び実施形態を詳細に説明する。図１は参考例によるリング材の矯正方法を説明するものであり、（ａ）は矯正すべきリング材１を示している。なお、図面では分かりやすくするため、このリング材１の扁平を誇張して示しており、楕円状に扁平化したリング材１の短径軸をＸ−Ｘ、長径軸をＹ−Ｙとしている。リング材１の実際の扁平量（＝最大径−最小径）は、リング材１の外径が２０００ｍｍの場合に、３〜１０ｍｍ程度である。
【００１１】
まず、このリング材１を加熱して拡径させる。この時の加熱温度は、リング材１を加熱して拡径させた時に、あらかじめ所定外形に設定してなる矯正治具（詳細は後述する）をリング材１の内面側に容易に装着しうる程度に拡径させるように定めればよく、具体的には、母材２が鋼材の場合には３００〜７５０°Ｃ程度に選定すればよい。加熱方法は、リング材１を炉に入れて全体を同時に加熱、昇温させてもよいし、リング材１の円周方向の一部領域を誘導加熱コイル等の局部加熱装置で加熱し、その局部加熱装置に対してリング材１を円周方向に相対的に移動させることで、リング材１の全周を加熱してもよい。
【００１２】
リング材１を所定温度に加熱して拡径した後、そのリング材１の内周面側に、図１（ｂ）に示すようにあらかじめ所定外形に設定してなる矯正治具４を装着する。ここで使用する矯正治具は、リング材１を冷却して縮径させる際、冷却中にリング材１の内周面を所定形状に拘束することができるものであれば任意であり、一定の外形に作られたものであってもよいし、外形を所望形状に変更させることができる外形調整機能を備えたものでもよいが、後者の方が利用範囲が広くなるので好ましい。図１の参考例では、外形調整機能を備えた矯正治具４を用いている。
【００１３】
図４はこの矯正治具４の概略平面図、図５はその矯正治具４の概略断面図である。５は円形の治具本体、６はその治具本体５に放射状に且つ放射方向の取り付け位置を調整可能に取り付けられた複数の調整部材であり、ここでは治具本体５にねじ係合して取り付けられたスタッドボルトが使用されている。７はそのスタッドボルトを固定するためのナット、８は各調整部材の先端に取り付けられ、リング材の内周面を支持する当金である。当金８は図４から良く分かるように円弧状の外面８ａを備えており、且つ調整部材６に対して回転自在に保持されている。かくして、当金８は回転させないで調整部材６のみを回転させて当金８の外面８ａの放射方向位置を調整でき、矯正治具４の外形（複数の当金８の外面によって形成される外形）を真円状、楕円状等任意に調整できる。
【００１４】
治具本体５に取り付ける調整部材６及び当金８は、リング材の内周面を円周方向に均等に規制することができるよう、円周方向に一定ピッチで配置することが好ましい。また、調整部材６及び当金８の使用個数は、多い程リング材の内周面の規制位置を多くして内周面規制の均等化が図れるので好ましいが、或る程度以上に多くすると内周面規制の均等化効果はあまり向上せず、一方、部品点数が多くなることによるコストアップ及び調整作業量の増加をもたらすという欠点を生じる。これらを考慮して、調整部材６及び当金８はそれぞれ、１２〜２０個設けることが好ましく、図面では１６個設けた例を示している。
【００１５】
図１（ｂ）に示す矯正治具４は、加熱、拡径したリング材１に取り付ける前に、調整部材６を調整して矯正治具４の外形を所定形状に設定しており、この実施形態では、あらかじめ設定する所定形状として、真円を採用している。真円状に設定した矯正治具４の外径は、リング材１をほぼ真円になるように矯正し且つ常温に冷却した後のリング材１の内径よりも少し大きく（例えば、０．１〜０．２％程度大きく）設定している。
【００１６】
次に、図１（ｃ）に示すように、加熱、拡径したリング材１内に、外形を真円状の所定形状に設定した矯正治具４を装着し、その後、リング材１を冷却して縮径させる。この冷却操作は、水冷、空冷、放冷、断熱材で覆った状態での放冷（徐冷）等の任意の方法を採用できるが、冷却による収縮時にリング材１の母材２と金属被覆層３（図６参照）との間の熱収縮量が異なって金属被覆層３に亀裂が発生する恐れのある場合には、冷却速度が遅くなるように、放冷或いは徐冷することが好ましい。この冷却により、図１（ｄ）に示すように、リング材１は矯正治具４の外面に接触する状態まで縮径し、その後は縮径しようとしても矯正治具４が内周面を拘束するため、縮径できず、このため、リング材１にはその矯正治具４を締め付けるたが張り力が発生し、リング材１は矯正治具４の外面に倣った形状に拘束される。すなわち、扁平状態のリング材１の短径軸Ｘ−Ｘ上の部分１ｘは曲率半径が小さくなるように変形し、長径軸Ｙ−Ｙ上の部分１ｙは曲率半径が大きくなるように変形し、その形状に拘束される。このようにリング材１を変形させ、その状態に拘束して常温に冷却することで、リング材１の上記倣い変形のかなりの部分が固定され、リング材１の扁平が矯正される。その後、リング材１から矯正治具４を取り外すことにより、扁平を矯正されたリング材１が得られる。なお、リング材１から矯正治具４を取り外すと、そのリング材１はたが張り力に起因する残留応力によりスプリングバックして縮径し、且つ縮径の際に扁平が幾分か戻るが、それによって生じる扁平量は元からあった扁平量に比べると小さいため、リング材１は最終的にはかなり真円に近い形状となる。かくして、扁平なリング材１の扁平を矯正できる。
【００１７】
以上の矯正操作において、矯正効果を増すには、矯正治具４の真円状に形成した外形の直径を大きくすることが有効である。すなわち、矯正治具４の外径を大きくしておくと、リング材１が、冷却初期の、かなり高温の状態で矯正治具４を締め付けた状態に変形するので、その変形は大部分が塑性変形となり、しかも、その後の冷却に伴う熱収縮力によってリング材１に生じる矯正治具４に対するたが張り力が大きくなり、大きいたが張り力で矯正治具の外形に拘束されるので、その形状に固定される効果が大きくなり、これによって扁平の矯正効果を増すことができる。しかしながら、矯正治具４の外径を大きくすると、冷却を終わって矯正治具４から取り外した後におけるリング材１の冷間でのスプリングバック縮径量が大きくなる。リング材１に形成している金属被覆層によっては、冷間での伸縮量を大きくすると亀裂が生じる場合があるので、その場合にはその亀裂が生じないように、矯正治具４の外径を設定すればよい。例えば、リング材１の母材２を炭素鋼とし、金属被覆層３を自溶性合金とした場合には、冷間の伸縮量が０．２〜０．２５％程度で亀裂が生じる場合が多いので、矯正治具４の外径を、リング材１の内径よりも０．１〜０．２％程度上回るレベルに留めることが好ましい。
【００１８】
なお、矯正治具４の外径をあまり大きくとれず、このため扁平矯正効果が低い場合、或いはリング材１の初期の扁平量が大きい場合などには、上記した扁平矯正動作を行った後でも、リング材１を所望の真円度まで矯正できない場合がある。その場合には、上記した動作を繰り返すことにより、扁平を更に矯正して真円度を上げることができ、所望の真円度を得ることができる。
【００１９】
図１に示す参考例では、矯正治具４の外形を真円状に設定したが、矯正治具４の外径は真円に限らず、他の形状としてもよく、例えば、リング材１の扁平状態とは逆の扁平状に設定することも可能である。図２はこの場合の参考例を示すものであり、図２（ａ）に示すように、矯正すべきリング材１が、横軸Ｘ−Ｘが短径軸、縦軸Ｙ−Ｙが長径軸となる扁平形状をなしていた場合に、図２（ｂ）に示すように、矯正治具４の外形形状を、リング材１の内面を９０度回転させた逆扁平状態（横軸Ｘ−Ｘが長径軸、縦軸Ｙ−Ｙが短径軸となる形状）とする。そして、図２（ｃ）に示すように、リング材１を加熱して拡径させた後、その内側に逆扁平状の矯正治具４を装着し、リング材１を冷却する。この冷却により、図２（ｄ）に示すように、リング材１は縮径して矯正治具４の外面に接触し且つその内周面が矯正治具４によって拘束され、リング材１には逆扁平状の矯正治具４の外面を締め付けるたが張り力が発生する。これにより、矯正前には曲率半径の大きかったリング材１の短径軸上の部分１ｘが、矯正治具４の外形の曲率半径の小さい長径軸（Ｘ−Ｘ）上の部分に押し付けられて狭められ、一方、矯正前には曲率半径の小さかったリング材１の長径軸上の部分１ｙが、矯正治具４の外形の曲率半径の大きい短径軸（Ｙ−Ｙ）上の部分に押し付けられて広げられ、この状態に拘束される。このようにリング材１を変形させ、その状態に拘束して常温に冷却することで、リング材１の倣い変形の一部が固定される。その後、リング材１を矯正治具４から外すと、リング材１は幾分か元の扁平状態に戻るため、真円に近づくこととなり、所望の真円度に矯正することができる。
【００２０】
矯正治具４の外形を逆扁平状に設定する場合において、その扁平度は通常、リング材１の扁平度にほぼ等しく設定されるが、これに限らず適宜増減可能である。また、逆扁平状に設定した矯正治具外形の平均直径は、扁平状のリング材１の内周面の平均直径にほぼ等しい値としてもよいし、それより少し大きく設定してもよい。矯正治具４の外形の平均直径は大きいほど、図１の参考例で説明したのと同様に矯正効果が増すが、あまり大きくすると真円を通り過ぎて逆扁平状になる恐れがあり、しかもリング材１の加熱、拡径量を大きくせざるを得なくなるので、これらを考慮して適正な値に設定すればよい。
【００２１】
以上に説明したように、リング材１の内周面側に装着する矯正治具４はその外形を真円状に設定しても良いし、逆扁平状に設定してもよい。一般に、矯正治具４の外形を図２に示す参考例のように逆扁平状に設定した方が、図１に示す参考例のように真円状に設定する場合に比べて、扁平矯正効果は大きい。しかしながら、この場合には、リング材１の短径部分を矯正治具４の長径部分に装着する関係上、リング材１の拡径量を大きくする必要がある。従って、これらの得失と、リング材の扁平量、物性等を考慮して、いずれかの方法を採用すればよい。
【００２２】
図３は本発明の実施形態を説明するものである。この実施形態では、図３（ａ）に示すように、リング材１を加熱、拡径する前に、その内周面側に矯正治具４を装着する。この時、矯正治具４はその外形を、リング材１内に装着しうるように小さくしている。次に、矯正治具４の各調整部材６を螺転させて治具本体５から放射方向に延び出させ、矯正治具４の外形を所望の矯正を行うための外形に設定する。この外形としては、図１、図２に示す参考例と同様に真円状としてもよいし、逆扁平状としてもよい。図３（ｂ）は矯正治具４の外形を真円に設定した場合であり、図３（ｃ）は矯正治具４の外形を逆扁平状に設定した場合であり、いずれの場合にも、リング材１は所定形状に設定した矯正治具４の外形に倣う形状に変形する。なお、この時、リング材１は冷間で変形させられるため、ほとんどが弾性変形であり内部には応力が発生している。
【００２３】
次に、図３（ｂ）或いは図３（ｃ）に示すように、矯正治具４を装着した状態のリング材１を加熱し、残留応力を減少させる。この時の加熱温度は、残留応力を緩和させることができるように定めればよく、具体的には、母材２が鋼材の場合には３００〜７５０°Ｃ程度に選定すればよい。加熱方法は、リング材１を炉に入れて全体を同時に加熱、昇温させてもよいし、リング材１の円周方向の一部領域を誘導加熱コイル等の局部加熱装置で加熱し、その局部加熱装置に対してリング材１を円周方向に相対的に移動させることで、リング材１の全周を加熱してもよい。その後、リング材１を冷却する。この冷却により、図１、図２に示す参考例で説明したのと同様に、リング材１が縮径し、図３（ｂ）或いは図３（ｃ）に示すように、リング材１の内周面が矯正治具４によって拘束され、リング材１には矯正治具４の外面を締め付けるたが張り力が発生する。これにより、矯正前には曲率半径の大きかったリング材１の短径軸上の部分１ｘが、矯正治具４によって狭められ、一方、矯正前には曲率半径の小さかったリング材１の長径軸上の部分１ｙが、矯正治具４によって広げられ、これによって、リング材１は真円に近づくように矯正される。その後、リング材１を矯正治具４から外すことでリング材を所望の真円度に矯正することができる。なお、この場合にも１回の矯正動作で所望の真円度が得られない場合には、同様な矯正動作を繰り返せば良い。
【００２４】
【実施例】
〔参考例１〕
図６、図７に示すリング材１を次の仕様で製造した。すなわち、母材２の材質はＳ２０Ｃ、金属被覆層３の材質はＮｉ−Ｃｒ系自溶合金、母材２の半径方向の厚さは３６．５ｍｍ、幅は７２ｍｍ、金属被覆層３の厚さは２．０ｍｍである。このリング材１の内外径を測定して表１に示す結果を得た。なお、表１における測定点は、図７に示す中心を通る各直線上である。表１から分かるように、このリング材１の外径及び内径の扁平量Δｄ（＝最大径−最小径）はそれぞれ、９．７ｍｍ、１０ｍｍであった。
【００２５】
【表１】

【００２６】
次に、図１（ｂ）に示すように、矯正治具４を、当金８で形成する外形が、直径１７６８．７ｍｍの真円となるように調整し、次いで、リング材１を炉によって５００°Ｃに加熱して拡径させ、その内部に矯正治具４を装着した。その後、リング材１を放冷して縮径させ、その内面を矯正治具４で拘束した。この状態で１０時間放置した。その結果、リング材温度は３２°Ｃに低下していた。その後、矯正治具４を外し、内外径を測定して、表２に示す結果を得た。表２より明らかなように、外径、内径の扁平量Δｄはそれぞれ、４．４ｍｍ、４．５ｍｍに低下しており、扁平矯正の効果があった。
【００２７】
【表２】

【００２８】
〔参考例２〕
参考例１と同じ仕様のリング材１を製造し、その内外径を測定して表３に示す結果を得た。表３から分かるように、このリング材１の外径及び内径の扁平量Δｄ（＝最大径−最小径）はそれぞれ、４．４ｍｍ、４．６ｍｍであった。
【００２９】
【表３】

【００３０】
次に、図２（ｂ）に示すように、矯正治具４を、当金８で形成する外形が、リング材１とは逆扁平状となるように、且つ表４で示す直径となるように調整した。この矯正治具４の外径は、リング材１の内径を９０°回転させたものと同一である。
【００３１】
【表４】

【００３２】
次に、リング材１を炉によって６００°Ｃに加熱して拡径させ、その内部に矯正治具４を装着した。その後、リング材１を放冷して縮径させ、その内面を矯正治具４で拘束した。この状態で１２時間放置した。その結果リング材温度は３０°Ｃに低下していた。その後、矯正治具４を外し、内外径を測定して、表５に示す結果を得た。表５より明らかなように、外径、内径の扁平量Δｄはそれぞれ、１．８ｍｍ、１．７ｍｍに低下しており、扁平矯正の効果があった。
【００３３】
【表５】

【００３４】
〔実施例１〕
参考例１と同じ仕様のリング材１を製造し、その内外径を測定して表６に示す結果を得た。表６から分かるように、このリング材１の外径及び内径の扁平量Δｄ（＝最大径−最小径）はそれぞれ、４．２ｍｍ、４．５ｍｍであった。
【００３５】
【表６】

【００３６】
次に、図３（ａ）に示すように、加熱する前のリング材１の内周面側に矯正治具４を装着し、次いで、その矯正治具４の調整部材６を調整して、その矯正治具４の外形を、図３（ｃ）に示すように、リング材１とは逆扁平状となるように設定した。この時の矯正治具４の外径は表７に示す通りであり、リング材１の内径を９０°回転させたものと同一とした。
【００３７】
【表７】

【００３８】
次に、矯正治具４を取り付けた状態のリング材１を炉によって６００°Ｃに加熱し、その後、炉から取り出し、リング材１を放冷して縮径させ、その内面を矯正治具４で拘束した。この状態で１２時間放置した。その結果リング材温度は３０°Ｃに低下していた。その後、矯正治具４を外し、内外径を測定して、表８に示す結果を得た。表８より明らかなように、外径、内径の扁平量Δｄはそれぞれ、１．５ｍｍ、１．３ｍｍに低下しており、扁平矯正の効果があった。
【００３９】
【表８】

【００４０】
【発明の効果】
以上のように、本発明のリング材の矯正方法は、扁平を矯正すべきリング材の内周面側に矯正治具を装着し且つその矯正治具の外形を前記リング材を変形させながら所定形状に設定し、その状態で前記リング材を加熱し次いでそのリング材を冷却することで、縮径するリング材に前記矯正治具を締め付けるたが張り力を発生させ、これにより前記リング材を前記矯正治具の外形に倣う形状に拘束しリング材の扁平を矯正する構成としたことにより、リング材を矯正治具から外した後においてもリング材を元の扁平形状よりも矯正治具の外形に近づく形状に矯正でき、従って、矯正治具の外形を適正に設定しておくことで、リング材を矯正治具から外した後において、リング材が所望の真円度になるように矯正することができるという効果を有している。
【図面の簡単な説明】
【図１】本発明の参考例による矯正方法を説明するものであり、（ａ）は矯正すべきリング材の概略平面図、（ｂ）は所定外形に設定した矯正治具の概略平面図、（ｃ）は加熱、拡径したリング材に矯正治具を装着した状態を示す概略平面図、（ｄ）は矯正治具を装着したリング材を冷却した状態で示す概略平面図
【図２】本発明の他の参考例による矯正方法を説明するものであり、（ａ）は矯正すべきリング材の概略平面図、（ｂ）は所定外形に設定した矯正治具の概略平面図、（ｃ）は加熱、拡径したリング材に矯正治具を装着した状態を示す概略平面図、（ｄ）は矯正治具を装着したリング材を冷却した状態で示す概略平面図
【図３】本発明の実施態様による矯正方法を説明するものであり、（ａ）は矯正すべきリング材の概略平面図、（ｂ）はリング材に装着した矯正治具を真円状の所定形状に設定した状態を示す概略平面図、（ｃ）はリング材に装着した矯正治具を逆扁平状の所定形状に設定した状態を示す概略平面図
【図４】本発明方法に用いる矯正治具の一例を示す概略平面図
【図５】図４に示す矯正治具の概略断面図
【図６】本発明で矯正の対象とするリング材の一例を示す概略断面図
【図７】図６に示すリング材の概略平面図
【符号の説明】
１リング材
２母材
３金属被覆層
４矯正治具
５治具本体
６調整部材
７ナット
８当金[0001]
BACKGROUND OF THE INVENTION
The present invention relates to how to correct so as to approach the flattened the ring member in the diameter direction to a perfect circle.
[0002]
[Prior art]
Recently, a ring material having a structure in which a hard metal coating layer is formed on an outer peripheral surface, an inner peripheral surface or an end surface of a large-diameter ring material having a diameter of 1 to 3 m in order to improve physical properties such as wear resistance is required. It has been. Accordingly, the inventors of the present invention, as a manufacturing method of the ring material having this configuration, first manufactures a ring material having a predetermined shape made of steel, and a self-fluxing alloy or the like on the outer peripheral surface, inner peripheral surface or end surface of the ring material. A method for forming a metal coating layer having a dense structure by spraying a material for forming a metal coating layer to form a sprayed layer and then heating and melting the sprayed layer was developed.
[0003]
[Problems to be solved by the invention]
However, the ring material manufactured by this method may be minute but flattened in the diametrical direction to be elliptical. For example, in a ring material having an outer diameter of 2000 mm, the difference between the maximum value and the minimum value of the outer diameter may be small. Flatness exceeding 10 mm sometimes occurred. The metal coating layer formed on the outer peripheral surface or inner peripheral surface of the ring material usually has a thickness of about 2 to 5 mm. Therefore, when the surface of the metal coating layer is ground and finished in a perfect circle, the above-mentioned flatness is obtained. As a result, the entire metal coating layer may be scraped off in some areas, and it is difficult to ensure a high yield and a high cost. Therefore, it has become necessary to correct the flatness of the ring material and bring it close to a perfect circle.
[0004]
The present invention has been made based on such demands, and an object thereof to provide Hisage corrective how possible ring member of the closer to a true circle correcting a flat large-diameter ring member.
[0005]
[Means for Solving the Problems]
[0006]
矯 positive method of the present invention, while the inner peripheral surface side equipped with a correcting jig and the outer shape of the straightening jig ring material to be corrected deforming said ring member is set to a predetermined shape, wherein in this state The ring material is heated, then the ring material is cooled and the correction jig is tightened on the ring material to generate a tension force, thereby restraining the ring material to a shape that follows the outline of the correction jig. It is configured to correct the flatness of the ring material. With this configuration, the residual stress of the ring material deformed when setting the external shape of the correction jig is relaxed by heating, and the ring material can be deformed and constrained to a shape that follows the external shape of the correction jig by subsequent cooling. Even after the ring material is removed from the correction jig, the ring material can be corrected to a shape that is closer to the outer shape of the correction jig than the original flat shape, and therefore, by appropriately setting the outer shape of the correction jig, After the ring material is removed from the correction jig, the ring material can be corrected to have a desired roundness.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The ring material to be corrected by the method of the present invention is arbitrary as long as it has a hollow cylindrical shape as a whole, and representative examples thereof include an inner peripheral surface as shown in FIGS. Ring material 1 in which metal coating layer 3 for improving the physical properties of the base material is formed on the outer peripheral surface of base material 2 whose outer peripheral surfaces are both simple cylindrical, or a metal coating layer is formed on the inner peripheral surface of base material 2 Can be mentioned. The ring material of this configuration is flattened to become an ellipse although it is a minute amount by heating during the melting treatment of the metal coating layer, and after that, it is necessary to grind the surface of the metal coating layer into a perfect circle For this reason, it is necessary to correct the flatness and bring it closer to a perfect circle before grinding, and the effect of applying the present invention is great.
[0009]
In addition, the ring material to be corrected is not limited to this structure, but may be a groove or a step formed on the outer peripheral surface, inner peripheral surface, end surface, etc. of the base material 2 or a change such as forming a flange, Moreover, the formation position of a metal coating layer can also be changed suitably, Furthermore, the thing of the structure which is not equipped with the metal coating layer may be sufficient. The base material constituting the ring material is arbitrary as long as it is a metal material. Specifically, carbon steel, low alloy steel, stainless steel, cast steel, cast iron, Ni base alloy, Cu base alloy, Al base alloy, etc. Can be mentioned. Further, the metal coating layer may be any material as long as it can improve the physical properties of the base material as desired. For example, a Ni-based alloy, a Co-based alloy, or WC, Cr ₃ C ₂ , TiB ₂ or the like may be used. The thing etc. which mix | blended hard material fine particles can be mentioned. The size of the ring material is not particularly limited, but a metal coating layer having a large diameter, for example, a large diameter such as an outer diameter of 1 to 3 m increases the flatness (= maximum diameter−minimum diameter). Therefore, the necessity of flattening correction is high, so that the merit of applying the method of the present invention is great.
[0010]
Hereinafter, reference examples and embodiments of the present invention will be described in detail. Figure 1 is intended to illustrate a method of correcting ring material with the reference example shows the ring material 1 to be corrected is (a). In addition, in order to make it easy to understand in the drawings, the flatness of the ring material 1 is exaggerated, and the minor axis of the elliptical flattened ring material 1 is XX and the major axis is YY. The actual flattening amount (= maximum diameter−minimum diameter) of the ring material 1 is about 3 to 10 mm when the outer diameter of the ring material 1 is 2000 mm.
[0011]
First, the diameter of the ring material 1 is increased by heating. The heating temperature at this time can be easily mounted on the inner surface side of the ring material 1 when the ring material 1 is heated to expand the diameter, and a correction jig (details will be described later) set in advance to a predetermined external shape is preliminarily set. What is necessary is just to determine so that it may expand to a grade, and, if the base material 2 is steel materials, what is necessary is just to select about 300-750 degreeC. As a heating method, the ring material 1 may be put into a furnace and the whole may be simultaneously heated and heated, or a partial region in the circumferential direction of the ring material 1 may be heated by a local heating device such as an induction heating coil, The entire circumference of the ring material 1 may be heated by relatively moving the ring material 1 in the circumferential direction with respect to the local heating device.
[0012]
After expanding the diameter of the ring material 1 by heating it to a predetermined temperature, a correction jig 4 having a predetermined external shape is set on the inner peripheral surface side of the ring material 1 as shown in FIG. . The correction jig used here is arbitrary as long as the ring material 1 can be cooled to reduce the diameter as long as the inner peripheral surface of the ring material 1 can be constrained to a predetermined shape during cooling. The outer shape may be made, or may be provided with an outer shape adjusting function capable of changing the outer shape to a desired shape, but the latter is preferable because the range of use is widened. In the reference example of FIG. 1, a correction jig 4 having an external shape adjustment function is used.
[0013]
FIG. 4 is a schematic plan view of the correction jig 4, and FIG. 5 is a schematic cross-sectional view of the correction jig 4. Reference numeral 5 denotes a circular jig body, and 6 denotes a plurality of adjustment members attached to the jig body 5 in a radial manner so that the radial attachment positions can be adjusted. Installed stud bolts are used. Reference numeral 7 denotes a nut for fixing the stud bolt, and 8 denotes an abutment that is attached to the tip of each adjustment member and supports the inner peripheral surface of the ring member. As can be clearly understood from FIG. 4, the abutment 8 has an arcuate outer surface 8 a and is held rotatably with respect to the adjustment member 6. Thus, it is possible to adjust the radial position of the outer surface 8a of the metal plate 8 by rotating only the adjusting member 6 without rotating the metal plate 8, and the external shape of the correction jig 4 (the external shape formed by the external surfaces of the plurality of metal plates 8). ) Can be arbitrarily adjusted such as a perfect circle or an ellipse.
[0014]
The adjustment member 6 and the metal plate 8 attached to the jig body 5 are preferably arranged at a constant pitch in the circumferential direction so that the inner circumferential surface of the ring material can be evenly regulated in the circumferential direction. In addition, it is preferable that the number of adjusting members 6 and the abutment 8 used is larger because the restriction position on the inner peripheral surface of the ring material can be increased to equalize the inner peripheral surface restriction. The equalization effect of the circumferential surface regulation is not improved so much, but on the other hand, the disadvantage is that the cost increases due to an increase in the number of parts and the amount of adjustment work increases. In consideration of these, it is preferable to provide 12 to 20 adjustment members 6 and the gold 8 respectively, and the drawing shows an example in which 16

adjustment members

6 and 16 are provided.
[0015]
The correction jig 4 shown in FIG. 1 (b) has the outer shape of the correction jig 4 set to a predetermined shape by adjusting the adjustment member 6 before being attached to the heated and expanded ring material 1. In the embodiment, a perfect circle is adopted as a predetermined shape set in advance. The outer diameter of the correction jig 4 set in a perfect circle is slightly larger than the inner diameter of the ring material 1 after the ring material 1 is corrected to be substantially circular and cooled to room temperature (for example, 0.1 (About 0.2% larger) is set.
[0016]
Next, as shown in FIG.1 (c), the corrective jig 4 which set the external shape to the predetermined shape of a perfect circle is mounted in the ring material 1 heated and expanded, and cooling the ring material 1 after that. To reduce the diameter. This cooling operation can employ any method such as water cooling, air cooling, natural cooling, or natural cooling (slow cooling) in a state covered with a heat insulating material, but the base material 2 of the ring material 1 and the metal coating when shrinking due to cooling. When the amount of heat shrinkage between the layer 3 (see FIG. 6) is different and the metal coating layer 3 may be cracked, it is preferable to cool or gradually cool so that the cooling rate becomes slow. . With this cooling, as shown in FIG. 1 (d), the ring material 1 is reduced in diameter to a state in contact with the outer surface of the correction jig 4, and thereafter, the correction jig 4 restrains the inner peripheral surface even if the diameter is reduced. For this reason, the diameter cannot be reduced. For this reason, the straightening jig 4 is fastened to the ring material 1, but a tension force is generated, and the ring material 1 is constrained to a shape following the outer surface of the straightening jig 4. That is, the portion 1x on the minor axis XX of the flat ring material 1 is deformed so that the radius of curvature is small, and the portion 1y on the major axis YY is deformed so that the radius of curvature is large. Restrained by its shape. As described above, the ring material 1 is deformed, constrained to the state, and cooled to room temperature, so that a substantial part of the ring material 1 is deformed and the flatness of the ring material 1 is corrected. Thereafter, by removing the correction jig 4 from the ring material 1, the ring material 1 whose flatness has been corrected is obtained. When the correction jig 4 is removed from the ring material 1, the ring material 1 springs back due to residual stress caused by the tensile force, and the diameter is reduced, and the flatness is somewhat restored when the diameter is reduced. Since the flatness generated thereby is smaller than the original flattening, the ring material 1 finally has a shape that is substantially close to a perfect circle. Thus, the flatness of the flat ring material 1 can be corrected.
[0017]
In the above correction operation, in order to increase the correction effect, it is effective to increase the diameter of the outer shape of the correction jig 4 formed in a perfect circle. That is, if the outer diameter of the straightening jig 4 is increased, the ring material 1 is deformed into a state in which the straightening jig 4 is fastened at a considerably high temperature in the initial stage of cooling, so that the deformation is mostly plastic. Further, the tension force on the correction jig 4 generated in the ring material 1 due to the heat shrinkage force caused by the subsequent cooling increases, and the large force is constrained to the outer shape of the correction jig by the tension force. The effect of fixing to the shape is increased, and this can increase the flattening correction effect. However, when the outer diameter of the correction jig 4 is increased, the amount of springback diameter reduction in the cold of the ring material 1 after the cooling is finished and removed from the correction jig 4 increases. Depending on the metal coating layer formed on the ring material 1, cracks may occur when the amount of expansion and contraction in the cold state is increased, and in this case, the outer diameter of the correction jig 4 is prevented so that the cracks do not occur. Should be set. For example, when the base material 2 of the ring material 1 is made of carbon steel and the metal coating layer 3 is made of a self-fluxing alloy, cracks often occur when the amount of cold expansion and contraction is about 0.2 to 0.25%. Therefore, it is preferable to keep the outer diameter of the correction jig 4 at a level that exceeds the inner diameter of the ring material 1 by about 0.1 to 0.2%.
[0018]
In addition, when the outer diameter of the correction jig 4 cannot be made so large, and therefore the flattening effect is low, or when the initial flattening amount of the ring material 1 is large, etc., even after performing the flattening operation described above. The ring material 1 may not be corrected to a desired roundness. In that case, by repeating the above-described operation, the flatness can be further corrected to increase the roundness, and a desired roundness can be obtained.
[0019]
In the reference example shown in FIG. 1, the outer shape of the correction jig 4 is set to a perfect circle. However, the outer diameter of the correction jig 4 is not limited to a perfect circle, and may be other shapes. It is also possible to set a flat shape opposite to the flat state. FIG. 2 shows a reference example in this case. As shown in FIG. 2 (a), the ring material 1 to be corrected is such that the horizontal axis XX is a short axis and the vertical axis YY is a long axis. 2B, as shown in FIG. 2B, the outer shape of the correction jig 4 is in an inverted flat state in which the inner surface of the ring material 1 is rotated by 90 degrees (horizontal axis XX). Is the major axis, and the vertical axis Y-Y is the minor axis. Then, as shown in FIG. 2 (c), after the ring material 1 is heated and expanded in diameter, an inverted flat correction jig 4 is mounted on the inside thereof, and the ring material 1 is cooled. Due to this cooling, as shown in FIG. 2 (d), the ring material 1 is reduced in diameter and comes into contact with the outer surface of the correction jig 4, and its inner peripheral surface is restrained by the correction jig 4. Tightening force is generated by tightening the outer surface of the reverse flat-shaped correction jig 4. Thereby, the portion 1x on the minor axis of the ring material 1 having a large curvature radius before correction is pressed against the portion on the major axis (XX) having a small curvature radius of the outer shape of the correction jig 4. On the other hand, the portion 1y on the major axis of the ring material 1 having a small curvature radius before correction is pressed against the portion on the minor axis (YY) having a large curvature radius of the outer shape of the correction jig 4 before being straightened. Is spread and restrained in this state. In this way, by deforming the ring material 1 and constraining the ring material 1 to cool to room temperature, a part of the copying deformation of the ring material 1 is fixed. Thereafter, when the ring material 1 is removed from the correction jig 4, the ring material 1 returns to the original flat state somewhat, so that it approaches a perfect circle and can be corrected to a desired roundness.
[0020]
When the outer shape of the correction jig 4 is set to an inverted flat shape, the flatness is generally set to be approximately equal to the flatness of the ring material 1, but the present invention is not limited to this and can be increased or decreased as appropriate. Moreover, the average diameter of the outer shape of the correction jig set in the reverse flat shape may be set to a value substantially equal to the average diameter of the inner peripheral surface of the flat ring material 1 or may be set slightly larger than that. As the average diameter of the correction jig 4 increases, the correction effect increases as described in the reference example of FIG. 1. However, if it is too large, there is a risk of passing through a perfect circle and becoming an inverted flat shape. Since heating of the material 1 and the amount of diameter expansion must be increased, an appropriate value may be set in consideration of these.
[0021]
As explained above, the outer shape of the correction jig 4 mounted on the inner peripheral surface side of the ring material 1 may be set to a perfect circle or may be set to a reverse flat shape. In general, when the outer shape of the correction jig 4 is set to an inverted flat shape as in the reference example shown in FIG. 2, the flattening effect is improved as compared to the case where it is set to a perfect circle shape as in the reference example shown in FIG. 1. Is big. However, in this case, it is necessary to increase the diameter expansion amount of the ring material 1 because the short diameter portion of the ring material 1 is attached to the long diameter portion of the correction jig 4. Therefore, any one of the methods may be adopted in consideration of these advantages and disadvantages, the flat amount of the ring material, physical properties, and the like.
[0022]
Figure 3 illustrates the implementation of the invention. In this embodiment, as shown in FIG. 3A, before the ring material 1 is heated and expanded in diameter, the correction jig 4 is mounted on the inner peripheral surface side. At this time, the outer shape of the correction jig 4 is reduced so that it can be mounted in the ring material 1. Next, each adjustment member 6 of the correction jig 4 is screwed to extend from the jig main body 5 in the radial direction, and the outer shape of the correction jig 4 is set to an outer shape for performing a desired correction. The outer shape may be a perfect circle shape as in the reference examples shown in FIGS. 1 and 2, or may be an inverted flat shape. FIG. 3B shows a case where the outer shape of the correction jig 4 is set to a perfect circle, and FIG. 3C shows a case where the outer shape of the correction jig 4 is set to an inverted flat shape. The ring material 1 is deformed into a shape that follows the outer shape of the correction jig 4 set to a predetermined shape. At this time, since the ring material 1 is deformed cold, most of the ring material is elastically deformed, and stress is generated inside.
[0023]
Next, as shown in FIG. 3B or FIG. 3C, the ring material 1 with the correction jig 4 attached is heated to reduce the residual stress. What is necessary is just to determine the heating temperature at this time so that a residual stress can be relieved, and what is necessary is just to select about 300-750 degreeC specifically, when the base material 2 is steel materials. As a heating method, the ring material 1 may be put into a furnace and the whole may be simultaneously heated and heated, or a partial region in the circumferential direction of the ring material 1 may be heated by a local heating device such as an induction heating coil, The entire circumference of the ring material 1 may be heated by relatively moving the ring material 1 in the circumferential direction with respect to the local heating device. Thereafter, the ring material 1 is cooled. This cooling reduces the diameter of the ring material 1 in the same manner as described in the reference examples shown in FIGS. 1 and 2, and as shown in FIG. 3B or FIG. The peripheral surface is constrained by the correction jig 4, and a tension force is generated on the ring material 1 because the outer surface of the correction jig 4 is tightened. Thereby, the portion 1x on the short axis of the ring material 1 having a large curvature radius before correction is narrowed by the correction jig 4, while the long axis of the ring material 1 having a small curvature radius before correction. The upper portion 1y is widened by the correction jig 4, whereby the ring material 1 is corrected so as to approach a perfect circle. Thereafter, the ring material 1 can be corrected to a desired roundness by removing the ring material 1 from the correction jig 4. In this case as well, if the desired roundness cannot be obtained by one correction operation, the same correction operation may be repeated.
[0024]
【Example】
[ Reference Example 1]
The ring material 1 shown in FIGS. 6 and 7 was manufactured with the following specifications. That is, the material of the base material 2 is S20C, the material of the metal coating layer 3 is a Ni—Cr self-fluxing alloy, the thickness of the base material 2 in the radial direction is 36.5 mm, the width is 72 mm, and the thickness of the metal coating layer 3 Is 2.0 mm. The inner and outer diameters of the ring material 1 were measured and the results shown in Table 1 were obtained. The measurement points in Table 1 are on each straight line passing through the center shown in FIG. As can be seen from Table 1, the flat amount Δd (= maximum diameter−minimum diameter) of the outer diameter and inner diameter of the ring material 1 was 9.7 mm and 10 mm, respectively.
[0025]
[Table 1]

[0026]
Next, as shown in FIG. 1 (b), the correction jig 4 is adjusted so that the outer shape formed by the metal 8 is a perfect circle having a diameter of 1768.7 mm. The diameter was increased by heating to 500 ° C., and the correction jig 4 was mounted therein. Thereafter, the ring material 1 was allowed to cool to reduce the diameter, and the inner surface thereof was restrained by the correction jig 4. This state was left for 10 hours. As a result, the ring material temperature was lowered to 32 ° C. Then, the correction jig 4 was removed, the inner and outer diameters were measured, and the results shown in Table 2 were obtained. As is clear from Table 2, the flatness Δd of the outer diameter and inner diameter decreased to 4.4 mm and 4.5 mm, respectively, and there was an effect of flattening.
[0027]
[Table 2]

[0028]
[ Reference Example 2]
A ring material 1 having the same specifications as in Reference Example 1 was produced, and the inner and outer diameters thereof were measured to obtain the results shown in Table 3. As can be seen from Table 3, the flat amount Δd (= maximum diameter−minimum diameter) of the outer diameter and inner diameter of the ring material 1 was 4.4 mm and 4.6 mm, respectively.
[0029]
[Table 3]

[0030]
Next, as shown in FIG. 2 (b), the correction jig 4 is formed so that the outer shape formed of the abutment 8 has a reverse flat shape with respect to the ring material 1 and the diameter shown in Table 4. Adjusted. The outer diameter of the correction jig 4 is the same as that obtained by rotating the inner diameter of the ring material 1 by 90 °.
[0031]
[Table 4]

[0032]
Next, the diameter of the ring material 1 was increased by heating to 600 ° C. in a furnace, and the correction jig 4 was mounted therein. Thereafter, the ring material 1 was allowed to cool to reduce the diameter, and the inner surface thereof was restrained by the correction jig 4. This state was left for 12 hours. As a result, the ring material temperature was lowered to 30 ° C. Thereafter, the correction jig 4 was removed, the inner and outer diameters were measured, and the results shown in Table 5 were obtained. As is apparent from Table 5, the flatness Δd of the outer diameter and the inner diameter decreased to 1.8 mm and 1.7 mm, respectively, and there was an effect of flattening.
[0033]
[Table 5]

[0034]
[Example 1 ]
A ring material 1 having the same specifications as in Reference Example 1 was produced, and the inner and outer diameters thereof were measured to obtain the results shown in Table 6. As can be seen from Table 6, the flat amount Δd (= maximum diameter−minimum diameter) of the outer diameter and inner diameter of the ring material 1 was 4.2 mm and 4.5 mm, respectively.
[0035]
[Table 6]

[0036]
Next, as shown in FIG. 3A, the correction jig 4 is mounted on the inner peripheral surface side of the ring material 1 before heating, and then the adjustment member 6 of the correction jig 4 is adjusted, The external shape of the correction jig 4 was set so as to have an inverted flat shape with respect to the ring material 1 as shown in FIG. The outer diameter of the correction jig 4 at this time is as shown in Table 7, and is the same as that obtained by rotating the inner diameter of the ring material 1 by 90 °.
[0037]
[Table 7]

[0038]
Next, the ring material 1 with the correction jig 4 attached is heated to 600 ° C. in a furnace, and then removed from the furnace, the ring material 1 is allowed to cool to reduce the diameter, and the inner surface of the ring material 1 is corrected. Restrained at. This state was left for 12 hours. As a result, the ring material temperature was lowered to 30 ° C. Then, the correction jig 4 was removed, the inner and outer diameters were measured, and the results shown in Table 8 were obtained. As is apparent from Table 8, the flatness Δd of the outer diameter and inner diameter was reduced to 1.5 mm and 1.3 mm, respectively, and there was an effect of flattening.
[0039]
[Table 8]

[0040]
【The invention's effect】
As described above, the method for correcting a ring material according to the present invention includes mounting a correction jig on the inner peripheral surface side of a ring material whose flatness is to be corrected, and changing the outer shape of the correction jig while deforming the ring material. By setting the shape and heating the ring material in that state and then cooling the ring material, the straightening jig is fastened to the ring material to be reduced in diameter, thereby generating a tension force. By constraining to the shape following the outer shape of the correction jig and correcting the flatness of the ring material, even after the ring material is removed from the correction jig, the ring material is more than the original flat shape. It can be corrected to a shape that approximates the outer shape. Therefore, by properly setting the outer shape of the correction jig, the ring material can be corrected to the desired roundness after being removed from the correction jig. Has the effect of being able to To have.
[Brief description of the drawings]
FIG. 1 illustrates a correction method according to a reference example of the present invention, in which (a) is a schematic plan view of a ring material to be corrected, (b) is a schematic plan view of a correction jig set to a predetermined outer shape, (C) is a schematic plan view showing a state in which a correction jig is attached to a heated and expanded ring material, and (d) is a schematic plan view showing a state in which the ring material to which the correction jig is attached is cooled. The correction method by the other reference example of this invention is demonstrated, (a) is a schematic plan view of the ring material which should be corrected, (b) is a schematic plan view of the correction jig set to the predetermined external shape, (c) ) Is a schematic plan view showing a state in which a correction jig is attached to a heated and expanded ring material, and (d) is a schematic plan view showing a state in which the ring material to which the correction jig is attached is cooled. real施態are intended to illustrate the straightening process according to the like, (a) shows the schematic plan of the ring member to be corrected in (B) is a schematic plan view showing a state in which the correction jig mounted on the ring material is set in a predetermined shape of a perfect circle, and (c) is a correction jig mounted on the ring material in a predetermined shape of an inverted flat shape. FIG. 4 is a schematic plan view showing an example of a correction jig used in the method of the present invention. FIG. 5 is a schematic cross-sectional view of the correction jig shown in FIG. 4. FIG. FIG. 7 is a schematic cross-sectional view showing an example of a ring material to be subjected to the inspection.
DESCRIPTION OF SYMBOLS 1 Ring material 2 Base material 3 Metal coating layer 4 Correction jig | tool 5 Jig body 6 Adjustment member 7 Nut 8 Gold

Claims

A method of correcting a ring material flattened in the diameter direction so as to approach a perfect circle, and mounting a correction jig on the inner peripheral surface side of the ring material, and deforming the outer shape of the correction jig The ring material is heated in that state, and then the ring material is cooled and the straightening jig is tightened on the ring material to generate a tension force. A method for correcting a ring material, wherein the flatness of the ring material is corrected by being constrained to a shape that follows the outer shape of the correction jig.

The method for correcting a ring material according to claim 1, wherein the predetermined outer shape set in the correction jig is a perfect circle .

A predetermined outer shape to be set to the correction jig, straightening method of claim 1 Symbol mounting ring member, characterized in that the opposite flat the ring material of the flat.