JP3993289B2

JP3993289B2 - Continuous casting mold

Info

Publication number: JP3993289B2
Application number: JP36564497A
Authority: JP
Inventors: 隆志津沢; 正昭松尾
Original assignee: JFE Steel Corp; Mishima Kosan Co Ltd
Current assignee: JFE Steel Corp; Mishima Kosan Co Ltd
Priority date: 1997-12-22
Filing date: 1997-12-22
Publication date: 2007-10-17
Anticipated expiration: 2017-12-22
Also published as: JPH11179491A

Description

【０００１】
【発明の属する技術分野】
本発明は、連続鋳造設備に用いる連続鋳造用鋳型に係り、更に詳しくは、短片が摺動当接する部位に擦り疵や局部摩耗疵が発生するのを防止できると共に、溶鋼注入初期に浸漬ノズルから注湯される溶鋼を受ける受湯領域にヒートクラックが発生するのを防止できる連続鋳造用鋳型に関する。
【０００２】
【従来の技術】
従来、溶鋼の連続鋳造が広汎に実施されており、最近では、２．０ｍ／分以上の高速度で鋳造する高速鋳造も盛んになっている。このような連続鋳造では、溶鋼を鋳込む鋳型の耐摩耗性が重要課題となっている。
そこで、例えば、図９（ａ）、（ｂ）に示すように、母材となる銅板５０の内側下部、即ち、鋳片殻（又は鋳片）が当接する部位にＮｉめっき５１を形成してなる長片５２を有する鋳型が提案されている。
しかし、この鋳型でも、内側下部、特に、下端近傍に摩耗が生じる。また、短片をスライドさせる幅可変の鋳型の場合、この短片が摺動する部位に擦り疵が発生する。
そこで、▲１▼前記内側下部、特に、下端近傍の摩耗を防止するため、図１０に示すように、Ｎｉめっき５１ａの下端近傍に、更に、Ｎｉ系合金めっき５３を形成してなる長片５４を有する鋳型が提案されている。
また、▲２▼前記短片が摺動する部位の摩耗を防止するため、図１１に示すように、銅板５０ａの内側上部にも薄いＮｉめっき５５を形成してなる長片５６を有する鋳型が提案されている。
【０００３】
【発明が解決しようとする課題】
しかしながら、前記▲１▼の鋳型においては、前記内側下部、特に、下端近傍の耐摩耗性を向上させることはできるものの、短片が摺動する部位の擦り疵を防止することができない。また、前記▲２▼の鋳型においては、受湯領域の上方に位置する内側上部、特に、溶鋼を連続鋳造する際、この鋳型内に貯溜される溶鋼のメニスカス近傍のめっき層にヒートクラックが発生するという問題がある。
本発明はかかる事情に鑑みてなされたもので、短片が摺動当接する長片の両内側側部に擦り疵が発生するのを防止することができると共に、溶鋼を連続鋳造する際、鋳型内に貯溜される溶鋼のメニスカス近傍域にヒートクラックが発生するのを防止することができる連続鋳造用鋳型を提供することを目的とする。
【０００４】
【課題を解決するための手段】
前記目的に沿う請求項１記載の連続鋳造用鋳型は、溶鋼注入初期に浸漬ノズルから注湯される溶鋼を受ける受湯領域を有する第１の長片、及び、該第１の長片に対向して平行に配置された第２の長片と、前記第１及び第２の長片の間に平行に配置された対となる短片を備えた枠状の連続鋳造用鋳型において、前記第１の長片の前記受湯領域に、Ｎｉめっきを形成すると共に、前記各短片が摺動当接する前記第１の長片の両内側側部、及び、凝固した鋳片殻が当接する前記第１の長片の内側下部であって、前記受湯領域を除く部分に、Ｎｉを０又は０を超え１５ｗｔ％以下含有する第１のＣｏ系めっきを形成し、更に、前記各短片が摺動当接する前記第２の長片の両内側側部、及び、前記鋳片殻が当接する前記第２の長片の内側下部に、Ｎｉを０又は０を超え１５ｗｔ％以下含有する第２のＣｏ系めっきを形成している。
請求項２記載の連続鋳造用鋳型は、請求項１記載の連続鋳造用鋳型において、前記Ｎｉめっき、及び、前記第１のＣｏ系めっきの厚みは同一であって、０．１〜２ｍｍの範囲にあり、しかも、前記第２のＣｏ系めっきの厚みは０．１〜２ｍｍの範囲にある。
【０００５】
本発明者等は、連続鋳造用鋳型について鋭意検討と実験を重ねた結果、以下のような知見を得た。
即ち、図５、図６に示すように、Ｃｏ系めっき中のＮｉ含有量が約６０ｗｔ％程度になるまでの範囲においては、このＮｉ含有量が高くなるにつれ、Ｃｏ系めっきの硬度は高くなるが、高温における摩耗減量は多くなる。これは、Ｃｏ金属が有する特有の高温摩耗性がＮｉが混入することによって損なわれると考えられる。従って、前記Ｎｉ含有量が約１５ｗｔ％以下、好ましくは１０ｗｔ％以下のときでは、その摩耗減量は比較的軽微である。
また、たとえ、上述したＣｏ系めっきであっても、長片の内面全面に施すと、溶鋼のメニスカス近傍のめっき層にヒートクラックが生じ、仮に、この部位の母材を露出するとヒートクラックを防止できることを知見し得た。
また、図７に示すように、溶鋼を連続鋳造する際、浸漬ノズル５７から注湯される溶鋼を片方の長片５２の内面に当てているため、溶鋼が当たる部位、即ち、受湯領域の熱衝撃が著しい。
従って、たとえ、上述したメニスカス近傍を避けて長片の内側下部にＣｏ系めっきを形成しても、図８に示すように、母材となるＣｕの伸び率と、Ｃｏ系めっき（Ｃｏ−１０ｗｔ％Ｎｉ）との伸び率が異なることに起因して、前記受湯領域にヒートクラックが生じる。なお、図中、符号５８はダミーバーである。
【０００６】
そこで、上述した受湯領域、即ち、長片の内側上部で露出される母材のＣｕと、長片の内側下部に皮膜されるＣｏ系めっきとの境界部に、これらの中間の伸び率を有するＮｉをめっきすると、上述したＣｕとＣｏ系めっきの伸び率の相違に依るヒートクラックの発生を防止することができることも知見し得た。
なお、上述した図５はＣｏ系めっき中のＮｉ含有量とＣｏ系めっきの硬度との関係を示す特性図、図６は３００℃におけるＣｏ系めっき中のＮｉ含有量とＣｏ系めっきの摩耗減量との関係を示す特性図、図８は材料の温度と伸び率の関係を示す特性図である。また、図６は高温摩耗試験の結果であり、Ｃｏ系めっきで作製されたテストピースにＳ４５Ｃ製のリングを約１０ｋｇ／ｃｍ²の面圧をかけた状態で、恒温炉内にセットし、約３００℃で、約３０分間、５０ｒｐｍのスピードで回転させた後の、テストピースの摩耗減量とリングの摩耗減量の総和を求めたものである。
【０００７】
従って、請求項１、２記載の連続鋳造用鋳型においては、第１の長片の各短片が摺動当接する両内側側部、及び、鋳片殻が当接する内側下部で、しかも、受湯領域を除く部分、そして、第２の長片の各短片が摺動当接する両内側側部、及び、鋳片殻が当接する内側下部に、Ｎｉを０又は０を超え１５ｗｔ％以下含有する硬い第１、第２のＣｏ系めっきを形成したので、擦り疵の発生を防止できると共に、鋳片殻に対する耐摩耗性を向上することができ、長寿命の鋳型を提供できる。また、浸漬ノズルから注湯される溶鋼を受ける第１の長片の受湯領域に、Ｎｉめっきを形成したので、母材の銅板が露出される内側上部と、第１のＣｏ系めっきを形成した内側下部との間で、伸び率の相違に依るヒートクラックの発生を防止することができる。
なお、Ｃｏ系めっき中のＮｉ含有量を、０又は０を超え１５ｗｔ％以下（以下、０〜１５ｗｔ％とする）、好ましくは０又は０を超え１０ｗｔ％以下としたのは、上述した如く（図５、図６参照）、前記Ｎｉ含有量が１０ｗｔ％を超えると、Ｃｏ系めっきの硬度は高くなるものの、耐摩耗性が低下し、特に、１５ｗｔ％を超えると、その傾向が著しくなるからである。
特に、請求項２記載の連続鋳造用鋳型においては、Ｃｏ系めっきやＮｉめっきの厚みを上述した範囲とすることにより、鋳型の内側にＣｏ系めっきやＮｉめっきを簡単に皮膜することができ、生産性を向上できると共に、鋳型が早期に使用できなくなるのを防止できる。
なお、ここで、Ｃｏ系めっきやＮｉめっきの厚みを０．１ｍｍ未満にすると、短期間のうちに擦り減って、早期に鋳型の寿命が尽きてしまい、逆に、２ｍｍを超えて皮膜することは製造上困難であるという欠点を有する。
【０００８】
また、Ｃｏ系めっきが形成される内側下部は、鋳造条件等にも依るが、長片の下端より、全高（Ｌ₁）の約１／５〜３／５程度、好ましくは約２／５〜３／５程度とする。これは、Ｃｏ系めっきの形成範囲が、全高の３／５を超えると、最も高温となる溶鋼のメニスカスに近づき過ぎてヒートクラックが生じ、逆に、全高の２／５未満になると、摩耗防止効果が低下して、早期に使用できなくなり、特に、全高の１／５未満になると、その傾向が著しくなるからである。
また、第１の長片の受湯領域にＮｉめっきを形成する場合、このＮｉめっきの形成範囲は、特に、溶鋼注入初期に浸漬ノズルから注湯される溶鋼を受ける受湯領域であれば、特に、規定されるものではない。
また、溶鋼注入初期に浸漬ノズルから注湯される溶鋼を第２の長片にも当てる場合は、この第２の長片の受湯領域にＮｉめっきを形成してもよい。また、短片の内側下部にＣｏ系めっきを形成してもよく、更に、溶鋼注入初期に溶鋼を短片に当てる場合は、この短片の受湯領域にＮｉめっきを形成してもよい。
更に、Ｃｏ系めっきやＮｉめっきは、長片の下端側に向かって、その厚みを厚くすると、更に耐摩耗性を向上することもできる。また、本発明の連続鋳造用鋳型は、幅固定の鋳型、又は、幅可変の鋳型のいずれであってもよい。
【０００９】
【発明の実施の形態】
続いて、添付した図面を参照しつつ、本発明を具体化した実施の形態につき説明し、本発明の理解に供する。
まず、図１〜図３を参照して、本発明の一実施の形態に係る連続鋳造用鋳型Ａについて説明する。
図１に示すように、連続鋳造用鋳型Ａは、適当間隔を開けて平行に配置した第１、第２の長片Ｂ、Ｃと、この第１、第２の長片Ｂ、Ｃの間に適当間隔を開けて平行に、しかも、第１、第２の長片Ｂ、Ｃと直交状に配置した一対の短片Ｄとを有している。なお、この連続鋳造用鋳型Ａを用いて連続鋳造する場合、この鋳型Ａの第１の長片Ｂの受湯領域に、溶鋼注入初期に浸漬ノズルから注湯される溶鋼を当てつつ、連続鋳造する。
従って、図２（ａ）、（ｂ）に示すように、第１の長片Ｂにおいては、銅又は銅合金からなる母材１１の両内側側部１１ａ、受湯領域（本実施の形態では、母材１１の内側下部１１ｂで、しかも、内側上部１１ｃとの境界部１１ｄの一部１１ｅとした）１１ｅ、更に、内側下部１１ｂであって、受湯領域１１ｅを除く部位１１ｆに、それぞれ、第１のＣｏ系めっきの一例であるＮｉを０〜１５ｗｔ％含み厚さ（ｔ₂）０．１〜２ｍｍの第１のＣｏ系合金めっき１２、厚さ（ｔ₃）０．１〜２ｍｍのＮｉめっき１３、第１のＣｏ系めっきの一例であるＮｉを０〜１５ｗｔ％含む厚さ（ｔ₂）０．１〜２ｍｍの第１のＣｏ系合金めっき１４が、それぞれ形成されている。
また、図３（ａ）、（ｂ）に示すように、第２の長片Ｃにおいては、溶鋼注入初期に浸漬ノズルから注湯される溶鋼を当てないため、銅又は銅合金からなる母材１５の両内側側部１５ａ、及び、内側下部１５ｂに、第２のＣｏ系めっきの一例であるＮｉを０〜１５ｗｔ％含む厚さ（ｔ₄）０．１〜２ｍｍの第２のＣｏ系合金めっき１６、１７が、それぞれ形成されている。
【００１０】
次に、本実施の形態に係る連続鋳造用鋳型Ａの製造方法について説明する。
まず、母材１１の両内側側部１１ａ、及び、内側下部１１ｂを、図示しない平面研削機で０．１〜２ｍｍ研削した後、この両内側側部１１ａ、及び、内側下部１１ｂに、それぞれ、母材１１の内側上部１１ｃと面一になるよう、厚さ０．１〜２ｍｍのＮｉめっきを形成する。
そして、両内側側部１１ａ、及び、内側下部１１ｂでしかも受湯領域１１ｅを除く部位１１ｆを、前記と同様、図示しない平面研削機で研削して、Ｎｉめっき１３を形成した後、この研削した両内側側部１１ａ、及び、内側下部１１ｂでしかも受湯領域１１ｅを除く部位１１ｆに、前記と同様、母材１１の内側上部１１ｃと面一になるよう、第１のＣｏ系合金めっき１２、１４を形成し、第１の長片Ｂを完成する。なお、母材１１の両内側側部１１ａ、及び、内側下部１１ｂを、図示しない平面研削機で０．１〜２ｍｍ研削した後、両内側側部１１ａ、及び、内側下部１１ｂに、それぞれ、母材１１の内側上部１１ｃと面一になるよう、厚さ０．１〜２ｍｍの第１のＣｏ系合金めっきを形成した後、受湯領域１１ｅを研削し、その部分にＮｉめっき１３を形成してもよい。
一方、第２の長片Ｃを製造する場合は、母材１５の両内側側部１５ａ、及び、内側下部１５ｂを、前記と同様、図示しない平面研削機を用いて０．１〜２ｍｍ研削した後、この研削した両内側側部１５ａ、及び、内側下部１５ｂに、それぞれ、母材１５の内側上部１５ｃと面一になるよう、第２のＣｏ系合金めっき１６、１７を形成する。
【００１１】
以上のように本実施の形態に係る連続鋳造用鋳型によれば、第１、第２の長片Ｂ、Ｃの両内側側部１１ａ、１５ａにそれぞれ、第１、第２のＣｏ系合金めっき１２、１６が形成されているので、たとえ、短片Ｄをスライドして鋳片の幅換えを行っても、この短片Ｄの摺動部である両内側側部１１ａ、１５ａに擦り疵が発生するのを防止できる。
また、第１の長片Ｂの内側下部１１ｂの受湯領域１１ｅを除く部位１１ｆ、第２の長片Ｃの内側下部１５ｂに、それぞれ、第１、第２のＣｏ系合金めっき１４、１７が形成されているので、溶鋼を連続鋳造する際、鋳片殻が接しても、摩耗して早期に寿命が尽きるのを防止することができる。
更に、溶鋼を連続鋳造する際、図示しない浸漬ノズルから注湯される溶鋼を受ける受湯領域１１ｅに、Ｎｉめっき１３を形成したので、高温の溶鋼によって母材１１と第１のＣｏ系合金めっき１４の伸び率の相違に依ってヒートクラックが発生するのを防止することができる。
【００１２】
【実施例】
次に、本実施の形態に係る連続鋳造用鋳型Ａの確認試験を行った結果について説明する。
まず、図１〜図３に示すような第１、第２の長片Ｂ、Ｃを有する連続鋳造用鋳型Ａを用意する。なお、第１、第２の長片Ｂ、Ｃの縦幅（Ｌ₁）は９４５ｍｍ、横幅（Ｌ₂）は２４８０ｍｍ、厚さ（ｔ₁）は４５ｍｍとした。
また、第１、第２のＣｏ系合金めっき１２、１６の横幅（Ｌ₅）はそれぞれ２００ｍｍ、第１、第２のＣｏ系合金めっき１４、１７の縦幅（Ｌ₃）は５００ｍｍ、その横幅（Ｌ₄）は２０８０ｍｍ、非めっき面である内側上部１１ｃ、１５ｃの縦幅（Ｌ₈）は４４５ｍｍとした。
また、Ｎｉめっき１３の縦幅（Ｌ₆）は２００ｍｍ、その横幅（Ｌ₇）は１４００ｍｍ、各めっき１２〜１４、１６、１７の厚さ（ｔ₂〜ｔ₄）は１ｍｍとした。また、母材１１、１５にはＣｕ−Ｃｒ−Ｚｒを使用した。
また、第１、第２のＣｏ系合金めっき１２、１４、１６、１７は、Ｎｉを１０ｗｔ％含有するＣｏ系合金めっきとした。また、図示しないが、短片Ｄには、Ｃｕ−Ｃｒ−Ｚｒからなる母材の内側下部に、Ｎｉを１０ｗｔ％含有するＣｏ系合金めっきを形成したものを使用した。
【００１３】
また、比較例として、図９に示すような内側下部にＮｉめっき５１を形成した長片５２を準備する。なお、前記と同様、長片５２の縦幅（Ｌ₁）は９４５ｍｍ、横幅（Ｌ₂）は２４８０ｍｍ、厚さ（ｔ₁）は４５ｍｍ、Ｎｉめっき５１の縦幅（Ｌ₃）は５００ｍｍ、厚さ（ｔ₅）は１ｍｍとした。また、母材にはＣｕ−Ｃｒ−Ｚｒを使用した。また、短片には、Ｃｕ−Ｃｒ−Ｚｒからなる母材の内側下部にＮｉめっきを形成したものを使用した。
この仕様で実機に使用したところ、比較例である長片５２を有する連続鋳造用鋳型は、８００チャージで交換する必要があったが、本実施の形態に係る連続鋳造用鋳型Ａでは、１３００チャージも連続して使用することができ、約１．６倍も寿命延長できた。
また、比較例において、短片をスライドさせて連続鋳造を行うと、鋳片のサイズやチャージ数等にもよるが、両サイドより１９５ｍｍ位置に局部摩耗が発生し、この局部摩耗減量が２ｍｍ以上にも達していたが、本実施の形態に係る連続鋳造用鋳型Ａでは、同じ鋳造条件で使用しても、この局部摩耗量を１ｍｍ以下に抑えることができた。
また、同じチャージ数連続鋳造した後で、第１、第２のＣｏ系合金めっきの摩耗減量を測定したところ、比較例の長片５２のＮｉめっきの摩耗量（例えば、１．５ｍｍ）に比較して、１／２以下（０．５ｍｍ程度）となった。
【００１４】
以上、本発明の実施の形態を説明したが、本発明は上記した実施の形態に限定されるものではなく、要旨を逸脱しない条件の変更等は全て本発明の適用範囲である。
例えば、本実施の形態では、第１の長片Ｂの母材１１の内側下部１１ｂで、しかも、内側上部１１ｃとの境界部１１ｄの一部を受湯領域１１ｅとしたが、例えば、図４に示すように、第１の長片Ｋの母材１９の両内側側部１９ａを除く内側下部１９ｂで、しかも、内側上部１９ｃとの境界部を受湯領域１９ｄとしてもよい。
なお、図４中、符号１８は受湯領域１９ｄに形成されたＮｉめっき、符号２０は母材１９の内側下部１９ｂで、受湯領域１９ｄを除く部位１９ｅに形成された第１のＣｏ系めっきの一例であるＮｉを０を超え１５ｗｔ％以下含有する第１のＣｏ系合金めっきである。
また、本実施の形態では、幅可変の鋳型Ａについて説明したが、幅固定の鋳型であってもよい。また、本実施の形態では、垂直型連続鋳造機に適用される鋳型Ａについて説明したが、湾曲型連続鋳造機に適用されるものであってもよい。
この場合、長片の内面を、鋳片が引き抜かれるストランドの曲率半径に応じた曲面状にすると共に、短片の両側面を、長片の内面形状に応じた曲面状にすればよい。
また、本実施の形態では、スラブを連続鋳造する鋳型Ａについて説明したが、ブルームを連続鋳造するものであってもよい。また、本実施の形態では、冷却水を通すスリットを省略したが、このスリットを設けたものであってもよい。
また、本実施の形態では、第１、第２の長片Ｂ、Ｃの両内側側部１１ａ、１５ａに、それぞれ第１、第２のＣｏ系合金めっき１２、１６を設けたが、この両内側側部１１ａ、１５ａの横幅（Ｌ₅）を、若干広め（例えば１０〜２０ｍｍ余分）に設けてもよい。
【００１５】
【発明の効果】
以上の説明から明らかなように、請求項１、２記載の連続鋳造用鋳型においては、擦り疵の発生を防止できると共に、鋳片殻に対する耐摩耗性を向上することができ、長寿命の連続鋳造用鋳型を提供できる。
また、浸漬ノズルから注湯される溶鋼を受ける受湯領域にＮｉめっきを形成したので、ヒートクラックの発生を防止することができる。
特に、請求項２記載の連続鋳造用鋳型においては、鋳型の内側に第１、第２のＣｏ系めっきを簡単に皮膜することができ、この結果、生産性を向上できると共に、短期間で鋳型の寿命が尽きてしまうのを防止できる。
【図面の簡単な説明】
【図１】本発明の一実施の形態に係る連続鋳造用鋳型の斜視図である。
【図２】（ａ）は同連続鋳造用鋳型の第１の長片の斜視図である。
（ｂ）は図２（ａ）の矢視Ｇ−Ｇ図である。
【図３】（ａ）は同連続鋳造用鋳型の第２の長片の斜視図である。
（ｂ）は図３（ａ）の矢視Ｈ−Ｈ図である。
【図４】同連続鋳造用鋳型の変形例の第１の長片の斜視図である。
【図５】Ｃｏ系めっき中のＮｉ含有量とＣｏ系めっきの硬度との関係を示す特性図である。
【図６】３００℃におけるＣｏ系めっき中のＮｉ含有量とＣｏ系めっきの摩耗減量との関係を示す特性図である。
【図７】連続鋳造の説明図である。
【図８】材料の温度と伸び率の関係を示す特性図である。
【図９】（ａ）は従来の連続鋳造用鋳型の長片の斜視図である。
（ｂ）は図９（ａ）の矢視Ｊ−Ｊ図である。
【図１０】従来の連続鋳造用鋳型の長片の斜視図である。
【図１１】従来の連続鋳造用鋳型の長片の斜視図である。
【符号の説明】
Ａ連続鋳造用鋳型Ｂ第１の長片
Ｃ第２の長片Ｄ短片
Ｋ第１の長片１１母材
１１ａ内側側部１１ｂ内側下部
１１ｃ内側上部１１ｄ境界部
１１ｅ受湯領域１１ｆ部位
１２第１のＣｏ系合金めっき（第１のＣｏ系めっき）
１３Ｎｉめっき
１４第１のＣｏ系合金めっき（第１のＣｏ系めっき）
１５母材１５ａ内側側部
１５ｂ内側下部１５ｃ内側上部
１６第２のＣｏ系合金めっき（第２のＣｏ系めっき）
１７第２のＣｏ系合金めっき（第２のＣｏ系めっき）
１８Ｎｉめっき１９母材
１９ａ内側側部１９ｂ内側下部
１９ｃ内側上部１９ｄ境界部（受湯領域）
１９ｅ部位
２０第１のＣｏ系合金めっき（第１のＣｏ系めっき）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a continuous casting mold used for continuous casting equipment. More specifically, the present invention can prevent generation of rubbing and local wear flaws at a portion where a short piece is slidably contacted, and also from an immersion nozzle at the beginning of molten steel injection. The present invention relates to a continuous casting mold that can prevent heat cracks from occurring in a hot water receiving region that receives molten steel to be poured.
[0002]
[Prior art]
Conventionally, continuous casting of molten steel has been widely carried out, and recently, high-speed casting in which casting is performed at a high speed of 2.0 m / min or more has become popular. In such continuous casting, the wear resistance of a mold into which molten steel is cast is an important issue.
Therefore, for example, as shown in FIGS. 9A and 9B, Ni plating 51 is formed on the inner lower portion of the copper plate 50 that is the base material, that is, the portion where the cast shell (or cast piece) contacts. A mold having a long piece 52 is proposed.
However, even in this mold, wear occurs in the inner lower part, particularly in the vicinity of the lower end. Further, in the case of a mold having a variable width for sliding the short piece, a rubbing crease is generated at a portion where the short piece slides.
Therefore, (1) in order to prevent wear in the inner lower part, particularly in the vicinity of the lower end, as shown in FIG. 10, a long piece 54 formed by further forming a Ni-based alloy plating 53 in the vicinity of the lower end of the Ni plating 51a. A mold has been proposed.
(2) In order to prevent wear of the portion where the short piece slides, as shown in FIG. 11, a mold having a long piece 56 formed by forming a thin Ni plating 55 on the inner upper portion of the copper plate 50a is proposed. Has been.
[0003]
[Problems to be solved by the invention]
However, in the mold of (1), although it is possible to improve the wear resistance of the inner lower part, particularly in the vicinity of the lower end, it is not possible to prevent scuffing at the site where the short piece slides. Further, in the mold of the above (2), when the molten steel is continuously cast, especially in the upper part located above the hot water receiving region, a heat crack is generated in the plating layer near the meniscus of the molten steel stored in the mold. There is a problem of doing.
The present invention has been made in view of such circumstances, and it is possible to prevent the occurrence of rubbing flaws on both inner side portions of the long piece with which the short piece comes into sliding contact. It is an object of the present invention to provide a continuous casting mold capable of preventing heat cracks from occurring in the vicinity of the meniscus of molten steel stored in the steel.
[0004]
[Means for Solving the Problems]
The continuous casting mold according to claim 1, which meets the above object, has a first long piece having a hot water receiving region for receiving molten steel poured from an immersion nozzle in the initial stage of pouring of the molten steel, and is opposed to the first long piece. In the frame-like continuous casting mold comprising the second long piece arranged in parallel and the pair of short pieces arranged in parallel between the first and second long pieces, In the hot water receiving area of the long piece, Ni plating is formed, both inner side portions of the first long piece that the short pieces slide and come into contact with, and the solidified cast piece shell that comes into contact with the first piece. A first Co-based plating containing Ni or more than 0 and not more than 15 wt% is formed on the inner lower part of the long piece except for the hot water receiving region, and each of the short pieces is slid Ni is applied to both inner side portions of the second long piece in contact with each other and to an inner lower portion of the second long piece in contact with the cast shell. Or forming a second Co-based plating containing less 15 wt% greater than 0.
The continuous casting mold according to claim 2 is the continuous casting mold according to claim 1, wherein the Ni plating and the first Co-based plating have the same thickness and are in a range of 0.1 to 2 mm. In addition, the thickness of the second Co plating is in the range of 0.1 to 2 mm.
[0005]
As a result of intensive studies and experiments on the continuous casting mold, the present inventors have obtained the following knowledge.
That is, as shown in FIG. 5 and FIG. 6, in the range until the Ni content in the Co-based plating reaches about 60 wt%, the hardness of the Co-based plating increases as the Ni content increases. However, wear loss at high temperatures increases. This is considered that the characteristic high temperature abrasion property which Co metal has is impaired by Ni mixing. Therefore, when the Ni content is about 15 wt% or less, preferably 10 wt% or less, the wear loss is relatively small.
Moreover, even if it is the Co-based plating described above, if it is applied to the entire inner surface of the long piece, a heat crack occurs in the plating layer near the meniscus of the molten steel, and if the base material in this part is exposed, the heat crack is prevented. I have learned that I can do it.
Further, as shown in FIG. 7, when continuously casting the molten steel, the molten steel poured from the immersion nozzle 57 is applied to the inner surface of one of the long pieces 52. Thermal shock is remarkable.
Therefore, even if Co-based plating is formed on the inner lower portion of the long piece while avoiding the vicinity of the meniscus described above, as shown in FIG. 8, the elongation percentage of Cu as a base material and Co-based plating (Co-10 wt. % Ni), the heat cracking occurs in the hot water receiving region. In the figure, reference numeral 58 denotes a dummy bar.
[0006]
Therefore, at the boundary between the hot water receiving region described above, that is, the base material Cu exposed at the inner upper portion of the long piece and the Co-based plating filmed at the inner lower portion of the long piece, an intermediate elongation ratio between them is set. It has also been found that when the Ni containing is plated, it is possible to prevent the occurrence of heat cracks due to the difference in elongation between Cu and Co-based plating described above.
5 is a characteristic diagram showing the relationship between the Ni content in the Co-based plating and the hardness of the Co-based plating, and FIG. 6 is the Ni content in the Co-based plating at 300 ° C. and the wear loss of the Co-based plating. FIG. 8 is a characteristic diagram showing the relationship between material temperature and elongation. FIG. 6 shows the result of the high temperature wear test. An S45C ring is applied to a test piece made of Co-based plating with a surface pressure of about 10 kg / cm ² and set in a constant temperature furnace. This is the sum of the wear loss of the test piece and the wear loss of the ring after rotating at 300 ° C. for about 30 minutes at a speed of 50 rpm.
[0007]
Therefore, in the casting mold for continuous casting according to claims 1 and 2, both the inner side portions where the short pieces of the first long piece are in sliding contact and the inner lower portion where the cast piece shell is in contact, Hardness containing Ni in excess of 0 or 0 and not more than 15 wt% in the portion excluding the region, both inner side portions where each short piece of the second long piece comes into sliding contact, and the inner lower portion where the cast piece shell comes into contact Since the first and second Co-based platings are formed, it is possible to prevent generation of scratches, improve wear resistance against the cast shell, and provide a long-life mold. Moreover, since Ni plating was formed in the hot water receiving area | region of the 1st long piece which receives the molten steel poured from the immersion nozzle, the inner upper part where the copper plate of a base material is exposed, and 1st Co type plating are formed. It is possible to prevent the occurrence of heat cracks due to the difference in elongation rate between the lower part and the inner lower part.
Note that the Ni content in the Co-based plating is 0 or more than 0 and 15 wt% or less (hereinafter referred to as 0 to 15 wt%), preferably 0 or more than 0 and 10 wt% or less as described above ( 5 and 6), when the Ni content exceeds 10 wt%, the hardness of the Co-based plating increases, but the wear resistance decreases. Particularly, when the Ni content exceeds 15 wt%, the tendency becomes remarkable. It is.
In particular, in the continuous casting mold according to claim 2, by setting the thickness of the Co plating or Ni plating in the above-described range, the Co plating or Ni plating can be easily coated on the inside of the mold, Productivity can be improved, and the mold can be prevented from becoming unusable early.
Here, if the thickness of the Co plating or Ni plating is less than 0.1 mm, it will be worn out in a short period of time, and the mold life will be exhausted at an early stage, and conversely, the coating will exceed 2 mm. Has the disadvantage of being difficult to manufacture.
[0008]
The inner lower portion where the Co-based plating is formed depends on casting conditions and the like, but is about 1/5 to 3/5 of the total height (L ₁ ) from the lower end of the long piece, preferably about 2/5 to 5/5. About 3/5. This is because if the formation range of Co plating exceeds 3/5 of the total height, it will be too close to the meniscus of the molten steel, which will be the hottest, and heat cracks will occur. This is because the effect is reduced and the device cannot be used at an early stage. In particular, when the total height is less than 1/5, the tendency becomes remarkable.
Moreover, when forming Ni plating in the hot water receiving region of the first long piece, the formation range of this Ni plating is particularly a hot water receiving region that receives molten steel poured from an immersion nozzle in the initial stage of molten steel injection. In particular, it is not specified.
Further, when the molten steel poured from the immersion nozzle is applied to the second long piece at the initial stage of the molten steel injection, Ni plating may be formed in the hot water receiving region of the second long piece. Further, Co-based plating may be formed on the inner lower portion of the short piece, and when the molten steel is applied to the short piece at the initial stage of molten steel injection, Ni plating may be formed in the hot water receiving region of the short piece.
Further, the wear resistance can be further improved by increasing the thickness of the Co plating or Ni plating toward the lower end side of the long piece. Further, the continuous casting mold of the present invention may be either a fixed width mold or a variable width mold.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
First, with reference to FIGS. 1-3, the casting mold A for continuous casting which concerns on one embodiment of this invention is demonstrated.
As shown in FIG. 1, the continuous casting mold A includes a first and second long pieces B and C arranged in parallel at an appropriate interval, and the first and second long pieces B and C. The first and second long pieces B and C are paired with a pair of short pieces D arranged at an appropriate interval in parallel with each other. In the case of continuous casting using this continuous casting mold A, continuous casting is performed while the molten steel poured from the immersion nozzle is applied to the hot water receiving region of the first long piece B of the casting mold A at the initial stage of molten steel injection. To do.
Accordingly, as shown in FIGS. 2A and 2B, in the first long piece B, both inner side portions 11a of the base material 11 made of copper or a copper alloy, a hot water receiving region (in this embodiment) In addition, the inner lower portion 11b of the base material 11 and a part 11e of the boundary portion 11d with the inner upper portion 11c), and the inner lower portion 11b, which is a portion 11f excluding the hot water receiving region 11e, respectively, An example of the first Co-based plating is a first Co-based alloy plating 12 containing 0 to 15 wt% of Ni and having a thickness (t ₂ ) of 0.1 to ₂ mm, and a thickness (t ₃ ) of 0.1 to 2 mm. An Ni plating 13 and a first Co alloy plating 14 having a thickness (t ₂ ) of 0.1 to ₂ mm containing 0 to 15 wt% of Ni, which is an example of the first Co plating, are formed.
Further, as shown in FIGS. 3 (a) and 3 (b), in the second long piece C, the molten steel poured from the immersion nozzle at the initial stage of molten steel injection is not applied, so that the base material made of copper or a copper alloy is used. The second Co-based alloy having a thickness (t ₄ ) of 0.1 to 2 mm containing Ni, which is an example of the second Co-based plating, on both the inner side portions 15a and the inner lower portion 15b. Plating 16 and 17 are formed respectively.
[0010]
Next, a method for manufacturing the continuous casting mold A according to the present embodiment will be described.
First, after both inner side parts 11a and inner lower part 11b of base material 11 were ground by 0.1-2 mm with a surface grinder (not shown), both inner side parts 11a and inner lower part 11b were respectively Ni plating with a thickness of 0.1 to 2 mm is formed so as to be flush with the inner upper portion 11 c of the base material 11.
Then, both the inner side portion 11a and the inner lower portion 11b and the portion 11f excluding the hot water receiving region 11e were ground with a surface grinder (not shown) to form the Ni plating 13 and then ground. Both the inner side portion 11a and the inner lower portion 11b, and the portion 11f excluding the hot water receiving region 11e, the first Co-based alloy plating 12, so as to be flush with the inner upper portion 11c of the base material 11, as described above. 14 is formed, and the first long piece B is completed. In addition, after both inner side parts 11a and inner lower parts 11b of the base material 11 are ground by 0.1 to 2 mm using a surface grinder (not shown), both inner side parts 11a and inner lower parts 11b are respectively formed on the mother parts 11a and 11b. After forming the first Co-based alloy plating having a thickness of 0.1 to 2 mm so as to be flush with the inner upper portion 11c of the material 11, the hot water receiving region 11e is ground, and the Ni plating 13 is formed in that portion. May be.
On the other hand, when manufacturing the 2nd long piece C, both the inner side part 15a and the inner lower part 15b of the base material 15 were ground 0.1-2 mm using the surface grinder which is not illustrated like the above. Thereafter, second Co-based alloy platings 16 and 17 are formed on the ground inner side portions 15a and the inner lower portion 15b so as to be flush with the inner upper portion 15c of the base material 15, respectively.
[0011]
As described above, according to the continuous casting mold according to the present embodiment, the first and second Co-based alloy platings are provided on the inner side portions 11a and 15a of the first and second long pieces B and C, respectively. 12 and 16 are formed, even if the short piece D is slid to change the width of the cast piece, scuffing occurs on both inner side portions 11a and 15a which are sliding portions of the short piece D. Can be prevented.
Further, the first and second Co-based alloy platings 14 and 17 are provided on the portion 11f of the inner lower portion 11b of the first long piece B excluding the hot water receiving region 11e and the inner lower portion 15b of the second long piece C, respectively. Since it is formed, even when the slab shell comes into contact with the continuous casting of the molten steel, it can be prevented from being worn out and having an end of its life at an early stage.
Furthermore, when continuously casting the molten steel, since the Ni plating 13 is formed in the hot water receiving region 11e that receives the molten steel poured from an immersion nozzle (not shown), the base material 11 and the first Co-based alloy plating are formed by the hot molten steel. Heat cracks can be prevented from occurring due to the difference in the elongation ratio of 14.
[0012]
【Example】
Next, the result of the confirmation test of the continuous casting mold A according to the present embodiment will be described.
First, a continuous casting mold A having first and second long pieces B and C as shown in FIGS. 1 to 3 is prepared. The vertical width (L ₁ ) of the first and second long pieces B and C was 945 mm, the horizontal width (L ₂ ) was 2480 mm, and the thickness (t ₁ ) was 45 mm.
The first and second Co-based alloy platings 12 and 16 have a lateral width (L ₅ ) of 200 mm, and the first and second Co-based alloy platings 14 and 17 have a vertical width (L ₃ ) of 500 mm. (L ₄ ) was 2080 mm, and the vertical widths (L ₈ ) of the inner upper portions 11c and 15c, which are non-plated surfaces, were 445 mm.
Moreover, the vertical width (L ₆ ) of the Ni plating 13 was 200 mm, the horizontal width (L ₇ ) was 1400 mm, and the thicknesses (t ₂ to t ₄ ) of the platings 12 to 14, 16 and 17 were 1 mm. Further, Cu—Cr—Zr was used for the base materials 11 and 15.
The first and second Co-based alloy platings 12, 14, 16, and 17 were Co-based alloy platings containing 10 wt% Ni. Moreover, although not shown in figure, the short piece D used what formed Co type alloy plating containing 10 wt% of Ni in the inner lower part of the base material which consists of Cu-Cr-Zr.
[0013]
Further, as a comparative example, a long piece 52 having Ni plating 51 formed on the inner lower portion as shown in FIG. 9 is prepared. As described above, the longitudinal width (L ₁ ) of the long piece 52 is 945 mm, the lateral width (L ₂ ) is 2480 mm, the thickness (t ₁ ) is 45 mm, and the vertical width (L ₃ ) of the Ni plating 51 is 500 mm, thick. The thickness (t ₅ ) was 1 mm. Further, Cu—Cr—Zr was used as a base material. Moreover, what used Ni plating in the inner lower part of the base material which consists of Cu-Cr-Zr was used for the short piece.
When this specification was used in an actual machine, the continuous casting mold having the long piece 52 as a comparative example had to be replaced with 800 charges. However, with the continuous casting mold A according to the present embodiment, 1300 charges were used. Can also be used continuously, extending the life by about 1.6 times.
In the comparative example, when continuous casting is performed by sliding a short piece, local wear occurs at a position of 195 mm from both sides, depending on the size of the slab and the number of charges, and the local wear loss is 2 mm or more. However, in the continuous casting mold A according to the present embodiment, the amount of local wear could be suppressed to 1 mm or less even when used under the same casting conditions.
Moreover, after the same number of charges were continuously cast, the wear loss of the first and second Co-based alloy plating was measured, and compared with the wear amount (for example, 1.5 mm) of the Ni plating of the long piece 52 of the comparative example. And it became 1/2 or less (about 0.5 mm).
[0014]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and all changes in conditions and the like that do not depart from the gist are within the scope of the present invention.
For example, in the present embodiment, a part 11d of the boundary portion 11d with the inner lower portion 11b of the base material 11 of the first long piece B and the inner upper portion 11c is used as the hot water receiving region 11e. As shown in FIG. 5, the inner lower portion 19b excluding both inner side portions 19a of the base material 19 of the first long piece K, and the boundary portion with the inner upper portion 19c may be used as a hot water receiving region 19d.
In FIG. 4, reference numeral 18 denotes Ni plating formed in the hot water receiving area 19 d, and reference numeral 20 denotes an inner lower part 19 b of the base material 19, and the first Co-based plating formed in the portion 19 e excluding the hot water receiving area 19 d. 1 is a first Co-based alloy plating containing more than 0 and not more than 15 wt%.
In the present embodiment, the variable width mold A has been described, but a fixed width mold may be used. Moreover, although this Embodiment demonstrated the casting_mold | template A applied to a vertical type continuous casting machine, you may apply to a curved type continuous casting machine.
In this case, the inner surface of the long piece may be curved according to the radius of curvature of the strand from which the cast piece is drawn, and both side surfaces of the short piece may be curved according to the inner surface shape of the long piece.
In the present embodiment, the mold A for continuously casting a slab has been described. However, the bloom may be continuously cast. Moreover, in this Embodiment, although the slit which lets cooling water pass was abbreviate | omitted, what provided this slit may be used.
In the present embodiment, the first and second Co-based alloy platings 12 and 16 are provided on the inner side portions 11a and 15a of the first and second long pieces B and C, respectively. The lateral width (L ₅ ) of the inner side portions 11a and 15a may be provided slightly wider (for example, an extra 10 to 20 mm).
[0015]
【The invention's effect】
As is apparent from the above description, in the continuous casting mold according to claims 1 and 2, it is possible to prevent the occurrence of rubbing and to improve the wear resistance against the slab shell, and to have a long service life. A casting mold can be provided.
Moreover, since Ni plating was formed in the hot water receiving area | region which receives the molten steel poured from the immersion nozzle, generation | occurrence | production of a heat crack can be prevented.
In particular, in the continuous casting mold according to claim 2, the first and second Co platings can be easily coated on the inside of the mold. As a result, the productivity can be improved and the mold can be formed in a short period of time. It is possible to prevent the end of the service life.
[Brief description of the drawings]
FIG. 1 is a perspective view of a continuous casting mold according to an embodiment of the present invention.
FIG. 2A is a perspective view of a first long piece of the continuous casting mold.
(B) is an arrow GG figure of Fig.2 (a).
FIG. 3A is a perspective view of a second long piece of the continuous casting mold.
(B) is a HH figure of the arrow of FIG. 3 (a).
FIG. 4 is a perspective view of a first long piece of a variation of the continuous casting mold.
FIG. 5 is a characteristic diagram showing the relationship between the Ni content in Co-based plating and the hardness of Co-based plating.
FIG. 6 is a characteristic diagram showing the relationship between the Ni content in Co-based plating at 300 ° C. and the wear loss of Co-based plating.
FIG. 7 is an explanatory diagram of continuous casting.
FIG. 8 is a characteristic diagram showing the relationship between the temperature and elongation rate of a material.
FIG. 9A is a perspective view of a long piece of a conventional continuous casting mold.
(B) is an arrow JJ figure of Fig.9 (a).
FIG. 10 is a perspective view of a long piece of a conventional continuous casting mold.
FIG. 11 is a perspective view of a long piece of a conventional continuous casting mold.
[Explanation of symbols]
A continuous casting mold B first long piece C second long piece D short piece K first long piece 11 base material 11a inner side part 11b inner lower part 11c inner upper part 11d boundary part 11e hot water receiving area 11f part 12 first Co-based alloy plating (first Co-based plating)
13 Ni plating 14 First Co-based alloy plating (first Co-based plating)
15 Base material 15a Inner side portion 15b Inner lower portion 15c Inner upper portion 16 Second Co-based alloy plating (second Co-based plating)
17 Second Co-based alloy plating (second Co-based plating)
18 Ni plating 19 Base material 19a Inner side part 19b Inner lower part 19c Inner upper part 19d Boundary part (hot water receiving area)
19e part 20 1st Co system alloy plating (1st Co system plating)

Claims

A first long piece having a hot water receiving region for receiving molten steel poured from an immersion nozzle at an initial stage of molten steel injection, and a second long piece arranged in parallel to face the first long piece, In a frame-shaped continuous casting mold provided with a pair of short pieces arranged in parallel between the first and second long pieces,
In the hot water receiving area of the first long piece, Ni plating is formed, both inner side portions of the first long piece, which the short pieces slide and abut, and solidified cast piece shells abut. Forming a first Co-based plating containing Ni in a lower portion of the first long piece, excluding the hot water receiving region, containing 0 or more than 0 and 15 wt% or less;
Further, Ni is 0 or more than 0 and exceeds 15 wt. On both inner side portions of the second long piece with which each short piece comes into sliding contact and with the inner lower portion of the second long piece with which the cast shell comes into contact. A casting mold for continuous casting, characterized in that a second Co-based plating containing not more than 50% is formed.

The thickness of the Ni plating and the first Co plating is in the range of 0.1 to 2 mm, and the thickness of the second Co plating is in the range of 0.1 to 2 mm. The continuous casting mold according to claim 1.