JP2004073897A

JP2004073897A - Crushing surface part member

Info

Publication number: JP2004073897A
Application number: JP2002233359A
Authority: JP
Inventors: Hajime Kawazu; 河津　肇
Original assignee: ING Shoji Co Ltd
Current assignee: ING Shoji Co Ltd
Priority date: 2002-08-09
Filing date: 2002-08-09
Publication date: 2004-03-11
Anticipated expiration: 2022-08-09
Also published as: JP3807734B2

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the crack of a roller main body caused by a discontinuous clad cross-sectional shape, peeling of a hardened clad metal and fall-out becoming problems when the thickness of the hardened clad metal is changed according to abrasion. <P>SOLUTION: An undercut part 12 continuous in the crushing direction is provided on the part of a base material surface subjected to remarkable abrasion in the direction orthogonal to the crushing direction. Ribs 13 consisting of a material having inferior abrasion resistance to the hardened clad metal are attached in the crushing direction with prescribed spaces. A first abrasion resistant hardened metal 14a is filled for cladding between the adjacent ribs 13 and 13 to bury the undercut part. A second abrasion resistant hardened metallic material is clad over the whole crushing surface on the first metallic material 14a. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、対向する破砕面の間に材料を連続的に噛み込んで粉砕する形式の粉砕機に使用される破砕面部材に関する。この形式の粉砕機として、例えばロール粉砕機、コーンクラッシャー、リングロールミル、竪型ローラミル、エッジランナー等がある。破砕面部材とは、このような粉砕機において破砕面を構成するロール、ローラ、タイヤ、テーブルライナー等を言う。
【０００２】
【従来の技術】
従来、鉄鉱石、石炭、コークス、黒鉛、転炉、高炉スラグ、石灰石、クリンカー、岩石等の各種材料を粉砕するために、ロール、ローラ、タイヤ、テーブルライナー等の破砕面部材を組み合わせた種々の粉砕機が使用されている。その中でもセメント工場におけるセメント原料を粉砕する竪型ローラミルは、非常に苛酷な磨耗環境に晒され、特にその粉砕ローラは、高クロム鋳鉄製ローラを使用した場合、破砕面である外周面におおよそ１００〜１２０ｍｍ程度の磨耗が早期に生じるが、その磨耗はローラ軸方向で極端な偏磨耗となる。材質が同じ鋳鋼ローラ、鋳鉄ローラの場合、この偏磨耗を防止する方法が無く、局部的な磨耗のため、部分的に肉厚が十分残っていてもローラを交換しなくてはならず、非常に不経済であった。
【０００３】
又、高クロム鋳鉄製ローラは、操業中に破損する危険性があり、耐磨耗性を与えるための炭化物を多量析出させると脆くなるので、炭化物の析出量を抑制せざるを得なかった。このため、耐磨耗性に劣り、長期の使用寿命を与えることが出来なかった。
【０００４】
このような偏磨耗を発生し材料効率が悪く短寿命の高クロム鋳鉄製ローラに代わり、肉盛りローラを採用すれば、肉盛りワイヤの選択により磨耗が抑制され、しかも偏磨耗対策が可能になり、使用寿命を延長することが出来るようになる。偏磨耗対策としては、ローラ外径が一定である事から、磨耗が顕著な部分に厚く肉盛りワイヤを溶着する必要があり、その部分で母材金属ローラを深く削り取らねばなら無い。従って、偏磨耗の少ない破砕面に較べ、アンダーカット部は深くなり、かつ深さが変化する部分で段差を伴う。
【０００５】
【発明が解決しようとする課題】
しかし、高クロム鋳鉄製ローラより寿命を延長するためには、優れた耐磨耗性を持つ硬化肉盛りワイヤを３０〜１００ｍｍ程度の厚みに厚肉盛りする必要がある。また、肉盛り断面は厚い部分と薄い部分が隣り合った不連続断面形状となり、セメント原料ミルローラのように硬化肉盛りワイヤを多量に肉盛りする場合、肉盛り量が約２〜３トンにも達するため、溶接肉盛りによる残留応力が莫大になり、母材金属ローラの段差部（不連続断面部）に集中が応力して、操業中の振動や高面圧荷重等が引きがねになって、母材金属に割れや破損が生じる危険性があった。
【０００６】
しかも、硬化肉盛り金属は多数の割れを発生するためにその割れが母材金属に伝播し易いことも影響した。又、硬化肉盛りワイヤを厚く肉盛りするために硬化肉盛り金属がローラ本体から剥離、脱落しやすい問題もあった。
【０００７】
本発明の目的は、肉盛り断面に不連続断面形状が存在するにもかかわらず、操業時の振動、高面圧荷重を受けても母材金属の割れや破損、硬化金属の剥離や脱落を防止できる破砕面部材を提供することにある。
【０００８】
【課題を解決するための手段】
上記目的を達成するめに、本発明の破砕面部材は、対向する破砕面の間に材料を連続的に噛み込んで粉砕する形式の粉砕機に使用され、前記破砕面に耐磨耗性硬化金属材料が肉盛りされた破砕面部材であって、破砕方向に直角な方向において顕著な磨耗を受ける部分の母材表面に、破砕方向に連続するアンダーカット部を設け、該アンダーカット部に、前記耐磨耗性硬化金属材料より耐磨耗性が劣る材料からなり、当該アンダーカット部の深さとほぼ同じ高さのリブを前記破砕方向に所定間隔で取り付け、隣接するリブ間に第１の耐磨耗性硬化金属材料を肉盛り充填し、第１の耐磨耗性硬化金属材料の上から破砕面全体に第２の耐磨耗性硬化金属材料を肉盛りしたものである。
【０００９】
セメント工場におけるセメント原料粉砕ミルローラのような巨大な寸法を持ち、肉盛り厚みが少なくとも３０ｍｍ以上を超える厚肉盛りを行なうローラ式粉砕機の粉砕ローラや粉砕テーブルの肉盛り製作に関して、局部磨耗を受ける粉砕面の母材金属ローラに硬化肉盛り金属を厚く肉盛りし、さほど磨耗を受けにくい破砕面に薄く肉盛りを行なって磨耗速度を合致させ粉砕機部材の使用効率を高める必要がある。
【００１０】
この要求に対しては、ローラ外径が一定であることから母材金属ローラに厚肉盛り部と薄肉盛り部との異なった肉盛り断面を形成しなくてはならず、厚肉盛り部は深くアンダーカットして、薄肉盛り部との肉盛り面に不連続な断面形状が形成される。操業中の高粉砕面圧や振動によりローラの断面不連続部に集中応力が生じてローラ本体に割れや硬化肉盛り金属に剥離，脱落を発生させる危険性が生じる。
【００１１】
このような割れや破損を防止するための簡便な対策として、本発明者は母材金属ローラのアンダーカット部にのみ耐磨耗性の低いリブをローラ周方向に所定間隔で取り付け、隣接するリブ間に耐磨耗性の高い硬化金属を埋め込む。耐磨耗性の低いリブがアンダーカット部内に多数存在することにより、不連続部に集中する応力が分断かつ分散され、これにより母材金属ローラの割れや破損が防止される。
【００１２】
更に、割れを多発する炭化物析出型合金肉盛りワイヤは、非常に耐磨耗性に優れている反面、脆く、多層肉盛りを行うと剥離し易い傾向がある。このような肉盛りワイヤを溶融させながら３０ｍｍを超え１００ｍｍまでローラの外周面に巻き付ける一般的な肉盛り方法を採用すると溶接残留応力が莫大になり、母材金属ローラと硬化金属との融合線に生じる冶金的不連続部に残留応力が集中してその融合線から一気に硬化金属が剥離、脱落する危険がある。このような剥離、脱落を生じない限界肉盛り厚みは、使用するワイヤの化学成分にもよるが、５０ｍｍ以下が安全である。しかるに、本発明を適用すれば、５０ｍｍを超える厚肉盛りが可能になり、剥離、脱落の発生を回避できる。
【００１３】
【発明の実施の形態】
以下に本発明の実施形態を図面に基づいて説明する。図１は本発明の一実施形態を示す粉砕ローラの縦断正面図及び縦断側面図、図２は同粉砕ローラが使用される竪型ローラミルの一部破断立面図である。
【００１４】
本実施形態の破砕面部材は、竪型ローラミルに使用される粉砕ローラである。竪型ローラミルは、セメント工場におけるセメント原料の粉砕等に使用される。この竪型ローラミルは、図２に示すように、テーブル２０上に円周方向に等間隔で配置された３個の粉砕ローラ１０を有する。テーブル２０は下方の駆動機構４０により回転駆動される。粉砕原料はミル中央からテーブル２０上に投入される。テーブル２０の中央部上に投入された粉砕原料は、テーブル２０の回転に伴う遠心力で中央部から外周方向に追いやられ、粉砕ローラ１０との間に噛み込まれる。
【００１５】
一般にスフェリカルローラと呼称されている３個の粉砕ローラ１０は、摩擦力によりテーブル２０に追従して回転しており、外周方向へ追いやられる粉砕原料を噛み込んで粉砕する。各粉砕ローラ１０に弾性機構３０で適切な面圧を加えることにより、必要とする微粉度を得る。粉砕ローラ１０の粉砕面である外周面に加わる面圧が莫大であることは前述したとおりである。
【００１６】
各粉砕ローラ１０は、図１に示すように、破砕面である外周面に、優れた耐磨耗性を持つ硬化金属１４を、幅方向（ローラ軸方向）で異なる厚みに肉盛りした偏厚肉盛りローラである。具体的に説明すると、母材金属ローラ１１の外周面は周方向に直角なローラ軸方向で湾曲した曲率半径Ｒの円弧面である。この外周面の幅方向中央部が幅方向でほぼ同じ厚みにアンダーカットされており、このアンダーカット部１２内に当該アンダーカット部１２の深さＤとほぼ同じ高さのリブ１３が、ローラ周方向に所定の間隔で配列され、母材金属ローラ１１の外周面に固定されている。
【００１７】
リブ１３は、硬化金属１４より耐磨耗性が低い材料からなり、隣接するリブ１３，１３間には第１の硬化金属１４ａが肉盛り充填されている。これにより、アンダーカット部１２内の肉盛りが完了し、その表面と両側の母材表面とが面一になる。そして更に、第１の硬化金属１４ａの上から母材金属ローラ１１の外周面全体に第２の硬化金属１４ｂが目標とする肉厚まで肉盛りされている。
【００１８】
第１の硬化金属１４ａの肉盛りは、フラックス入り硬化肉盛りワイヤを使用するノンガスアーク、炭酸ガスアーク溶接等により施工される。第２の硬化金属１４ｂの肉盛りは、ローラ外周面に同じくフラックス入り硬化肉盛り溶接ワイヤを溶融させながら巻き付ける方法で施工される。
【００１９】
このように２通りの肉盛り方法が適用されることにより、磨耗が顕著な偏磨耗部が厚肉盛りとされるが、アンダーカット部においては、耐磨耗性が低いリブを用いたスリット肉盛り法により、厚肉盛りにより発生する溶接残留応力が無害化される。更にその上に溶接硬化ワイヤによる溶融金属を巻き付け肉盛りすることにより、所定の肉厚分布の硬化金属が形成され長寿命化が図られる。
【００２０】
更なる特徴は、円周巻き付け肉盛り部（第２の硬化金属部）が磨耗消失してから、スリット肉盛り部（リブもつ第１の硬化金属部）が現れ、低下しつつある粉砕能力がスリット肉盛り部の優れた噛み込み性により回復し再度維持されるようになり、結果として全肉盛り厚みに対して粉砕能力が持続するようになる。
【００２１】
耐磨耗性の低いリブの材質には、通常軟鋼、炭素鋼、１４％マンガン鋼、ステンレス鋼等板が選択される。これら材質は、母材金属ローラと同じ材質であるか若しくは優れた靭性を持つ。またリブの板厚は、６〜９ｍｍが望ましく、その高さはアンダーカット深さにほぼ相当する深さが選択される。リブの取り付け間隔は３０〜５０ｍｍが好ましい。これらのリブはアンダーカット部内に溶接で取り付けられる。隣接するリブに囲まれた空間に溶接硬化肉盛りワイヤが充填肉盛りされてアンダーカット部の肉盛り施工が完了する。
【００２２】
溶接残留応力は、もしリブ（隔壁）が存在しないと仮定すれば、肉盛りワイヤはローラ円周上に巻き付ける方法で肉盛りされるようになり、破砕部断面から見れば、アンダーカットされた機械加工線と融合して境界を形成する溶接融合線がローラ円周上に連続して形成され、この融合線は冶金的な不連続部を形成するために、その部分に応力集中を招来するようになる。冶金的な不連続線となる理由としては、母材金属ローラと溶接硬化肉盛りワイヤとが異質材料で、それぞれの物理的性質が圧倒的に異なることと、硬化肉盛り金属には多数の割れが発生しており、この割れが伝播してローラ素材の割れや破壊に繋がる危険性が大きくなることがある。特に溶着金属が厚く肉盛りされればされる程、溶接残留応力が増大して、割れ伝播の危険性が高くなり、硬化金属が一挙にローラ本体から剥離、脱落し易くなる。したがって、連続した冶金的な不連続部の形成は、応力集中の点から絶対避けねばならないことである。
【００２３】
このような観点から、耐磨耗性の低いリブ、代表的には軟鋼壁は、ローラ円周上に等間隔で多数溶接により取り付けられており、軟鋼壁で形成された各空間毎に溶接肉盛りが完了されるために、応力発生は各ブロック内部に閉じ込められ分散されるので、連続肉盛りに較べ応力蓄積が大幅に軽減される。又、軟鋼壁が肉盛り中に変形して溶接残留応力を吸収する点からも、応力蓄積が軽減される。
【００２４】
耐磨耗性の低いリブ、代表的には軟鋼壁は、冶金的な不連続線を断ち切る効果を発揮して応力集中を防止し、操業中には、ローラの粉砕面が受ける繰り返しせん断応力を吸収し、脆い溶着金属の剥離脱落をも防止する。
【００２５】
ローラ円周巻き付け肉盛り方法では、連続した肉盛り線をローラ全周に形成するので、母材金属と溶接肉盛り金属との間の冶金的な不連続線がローラ全周に形成されることになる。そして、その部分に溶接残留応力が集中して、一旦割れが発生すると、割れはその線上を伝播し続けて溶接残留応力が完全に解放されるまで伝播する。
【００２６】
このような集中応力による母材割れや硬化金属の剥離、脱落、破損を防止するためのリブの効果は、（１）その板厚、（２）取り付け本数、（３）その高さなどにより大きな影響を受ける。
【００２７】
（１）リブの板厚ｗは、隣接するリブの間隔、即ちこの間の第１の硬化金属のローラ周方向長さをＷとして、０．１Ｗ≦ｗ≦Ｗの範囲内が好ましい。例えば、Ｗ＝５０ｍｍの場合、ｗの範囲は５．０ｍｍ〜５０ｍｍになる。ｗを大きくすれば、ローラ素材の補強ブロックの効果が増大し、ローラ素材の破損を防止する上で非常に有効になる。しかし、あまり厚くすると、耐磨耗硬化金属の長さが減少して磨耗が促進されるようになる。又、あまり小さくすると補強部材としての効果も無くなる。実際に最も多く適用される板厚ｗの範囲は６．０〜１２ｍｍである。
【００２８】
（２）リブの取り付け本数が多いほど母材ローラや硬化金属の剥離、脱落防止に効果があるが、その取り付け本数は、ｗの大きさ、Ｗの大きさにより決定される。実際面から考慮すれば、板厚ｗは６〜１２ｍｍの範囲にあり、Ｗの大きさ、即ち耐磨耗性に優れた第１の硬化金属の長さは２０〜６０ｍｍの範囲が考慮されるが、実用上、最も多く選択されるＷは３０〜５０ｍｍの範囲である。これらの２因子で取り付け枚数が決定される。
【００２９】
（３）リブの高さは、素材ローラの割れや破損、硬化肉盛り金属の剥離、脱落という２つの問題を解決するための最も有効な因子になる。硬化金属の肉盛り厚が３０ｍｍを超え１００ｍｍまで肉盛りする場合、一般的にローラの肉盛り方法に採用されているローラ円周方向に肉盛りワイヤを溶融させて巻き付ける方法によれば、５０ｍｍを超える溶着金属を肉盛りすると、ローラ母材との境界線から一気に応力解放するための剥離、脱落を生じる危険性が高い。その理由は、素材ローラと硬化肉盛り金属の性質が著しく異なるために、その融合線に一種の冶金的な不連続部が形成され、その部分に多層肉盛りにより生じた溶接残留応力が集中してローラ素材に割れを発生させ、硬化肉盛り金属の剥離や脱落を発生させる。硬化肉盛り金属の場合には５０ｍｍを超えると剥離、脱落の危険性が生じるようになるが、素材ローラに発生する割れや脱落は硬化金属の厚みが３０ｍｍ以上から発生していた。
【００３０】
Ａ）硬化肉盛り金属の脱落を防止できるスリット肉盛り厚み（第１硬化金属厚）は、全硬化金属厚みとの関係で表すと表１のとおりである。円周巻き付け肉盛り（第１硬化金属）の限界厚みは５０ｍｍである。硬化金属の剥離、脱落に関しては、５０ｍｍ以上の肉厚を与えると、これが発生するので、スリット肉盛りの厚みは、全肉厚から剥離肉厚５０ｍｍを差し引いた厚みを適用すれば良い。
【００３１】
【表１】

【００３２】
Ｂ）母材金属の割れ、破損を防止できるスリット肉盛り厚み（第１硬化金属厚）は、全硬化金属厚みとの関係で表すと表２のとおりである。母材金属の割れ、脱落に関しては、硬化金属の厚みが３０ｍｍを超えて発生する。従って、母材の割れや破損を防止するためのスリット肉厚は全硬化金属の厚みの１／３以上となる。
【００３３】
【表２】

【００３４】
Ａ）Ｂ）の両条件を満足する範囲を総括すると表３になる。ここに記載されたスリット肉盛り厚み（第１硬化金属厚）を採用することにより、硬化肉盛り金属の脱落、母材金属の割れ、破損の両方を防止できる。即ち、大きいほうのスリット肉盛り厚み（第１硬化金属厚）、具体的には全硬化金属厚みが８０ｍｍ未満の場合はＢ）を採用し、全硬化金属厚みが８０ｍｍ以上の場合はＡ）を採用することにより、硬化肉盛り金属の脱落、母材金属の割れ、破損の両方を防止できる。
【００３５】
【表３】

【００３６】
従来、一般的に使用されているローラ円周にワイヤを溶融させて巻き付ける肉盛り方法に関しては、硬化金属の肉厚が約３０ｍｍ以上から素材ローラの一部に割れを発生する危険性が増大し、さらに硬化金属の肉厚が５０ｍｍ以上を超えるとその一部の割れを起点として、２０ｍｍ厚く肉盛りしたことによる溶接残留応力の増加により、一気に硬化金属との境界部から引き裂く剥離、脱落が発生した。これは、溶接残留応力が完全に解放されバランスが取れる距離まで亀裂が進展し、その間の溶着金属が剥離、脱落することに繋がった。本実施形態によるとこれが効果的に防止され、３０ｍｍ以上、更には５０ｍｍ以上の硬化金属肉厚が可能になる。
【００３７】
【実施例】
セメント工場におけるスラグ、クリンカー粉砕ローラに関しての実施例を説明する。
【００３８】
粉砕機は、１時間当たり９０〜１００トン／時の粉砕能力を持つ竪型ローラミル（図２）である。粉砕ローラ（図１）は、重量が７〜１０トン、最大直径が約２３００ｍｍ、最大幅が約７００ｍｍという巨大ローラである。ローラ素材肉厚は最大径部で約１６０ｍｍである。粉砕ローラの粉砕面に加わる面圧は莫大であり、外周の破砕面に肉盛りされた硬化金属の断面形状が不連続形状になって場合、高面荷重により不連続部に集中応力が発生してローラ素材に割れが多発する。その割れはローラ素材表面上の無数の不規則な場所から垂直に進展しており、その最大深さは約５０ｍｍにも達し、破壊の危険性もあった。また、ある場合には、ローラの外周面ににほぼ平行な剥離割れを生じることもあった。母材金属ローチの材質は鋳鋼であり、ＪＩＳ炭素鋼鋳鋼品ＳＣ４６０相当品である。
【００３９】
特に鋳鋼品の場合は、結晶の成長に方向性があり、最後に凝固する。粒界に低融点の不純物が集積し易く、高面圧を受ける用途では、上記粒界に沿って割れや破壊を発生し易い性質がある。
【００４０】
このような状況下で、アンダーカット部にスリット方法を適用することにした。硬化金属の全肉厚は６０ｍｍであり、母材金属ローラ表面（アンダーカット部の底面）から３５ｍｍまでリブによるスリット方法を採用した。但し、３５ｍｍのうらの下５ｍｍは下盛り層で耐磨耗性は無い。あくまで割れ伝播防止用として肉盛り層である。
【００４１】
リブは軟鋼壁であり、９ｍｍのフラットバー材を使用し肉厚ｗを９ｍｍとした。その高さは前述したとおり３５ｍｍである。ローラ素材面の幅方向中央部に形成された深さ３５ｍｍのアンダーカット部内に１２０個のリブを約５０ｍｍの等間隔で溶接により取り付けた。アンダーカット部を埋めるリブ間のスリット肉盛りは、ＳＢ−０ワイヤを使用した埋め込み肉盛り施工である。
【００４２】
スリット肉盛り完了後、スリット肉盛り面を含めたローラの外周面全体に約２５ｍｍ厚みにＳＢ−０ワイヤを溶融させながら巻き付けた。ＳＢ−０ワイヤの化学成分はＣ：４．５％、Ｃｒ：２２％、Ｎｂ：７．０％、Ｍｏ：２．０％、Ｖ：１．５％であり、硬度はＨＶ７５０〜８５０、磨耗係数は２．８〜４．０である。
【００４３】
従来、この種の破砕ローラは、耐磨耗性付与のために、アンダーカット部を含め高クロム鋳鉄系ワイヤでローラ円周巻き付け肉盛り施工方法を実施していたが、使用開始から約２，０００時間で母材金属ローラの亀裂発生や硬化金属の剥離、脱落を生じ、交換を余儀なくされていた。しかるに、本実施例のローラは、約４，０００〜６，０００時間を経過しても、硬化金属の剥離やローラ素材の亀裂を発生することが無かった。
【００４４】
【発明の効果】
以上に説明したとおり、本発明の破砕面部材は、セメント工場におけるセメント原料粉砕ミルローラのような巨大な寸法を持ち、肉盛り厚みが少なくとも３０ｍｍ以上を超える厚肉盛りを行なうローラ式粉砕機の粉砕ローラや粉砕テーブルの肉盛り製作に関して、局部磨耗を受ける粉砕面の母材金属ローラに硬化肉盛り金属を厚く肉盛りし、さほど磨耗を受けにくい破砕面に薄く肉盛りを行なって磨耗速度を合致させ粉砕機部材の使用効率を高めるような場合にあって、深くアンダーカットした厚肉盛り部と薄肉盛り部との間に形成される不連続な断面形状の不連続部に操業中の高粉砕面圧や振動により集中応力が生じることによる母材金属ローラの割れや硬化肉盛り金属の剥離、脱落を、簡易な施工法により効果的に防止できる。これにより５０ｍｍを超える厚肉盛りを可能し、母材金属ローラの割れ防止、硬化金属の剥離、脱落の防止と合わせ、従来より格段に長い使用寿命を実現できる。
【図面の簡単な説明】
【図１】（ａ）は本発明の一実施形態を示す粉砕ローラの縦断正面図、（ｂ）は（ａ）中のＡ−Ａ線矢示図で、同粉砕ローラの主要部の縦断側面図である。
【図２】同粉砕ローラが使用される竪型ローラミルの一部破断立面図である。
【符号の説明】
１０　粉砕ローラ
１１　母材金属ローラ
１２　アンダーカット部
１３　リブ
１４　硬化金属
２０　テーブル[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a crushing surface member used in a crusher of a type in which a material is continuously bitten between opposing crushing surfaces and crushed. Examples of this type of crusher include a roll crusher, a cone crusher, a ring roll mill, a vertical roller mill, and an edge runner. The crushing surface member refers to a roll, a roller, a tire, a table liner, or the like that forms a crushing surface in such a crusher.
[0002]
[Prior art]
Conventionally, in order to pulverize various materials such as iron ore, coal, coke, graphite, converter, blast furnace slag, limestone, clinker, and rock, various types of crushing surface members such as rolls, rollers, tires, and table liners are combined. A crusher is used. Among them, a vertical roller mill for crushing cement raw materials in a cement factory is exposed to a very severe wear environment. In particular, when a high chromium cast iron roller is used, the crushing roller is approximately 100 mm on the outer peripheral surface which is a crushing surface. Although abrasion of about 120 mm occurs at an early stage, the abrasion becomes extremely uneven abrasion in the roller axis direction. In the case of cast steel rollers and cast iron rollers of the same material, there is no way to prevent this uneven wear, and due to local wear, the rollers must be replaced even if the wall thickness is still partially sufficient. Was uneconomical.
[0003]
Further, the high chromium cast iron roller has a risk of being broken during operation, and becomes brittle when a large amount of carbide for imparting abrasion resistance is precipitated, so that the amount of carbide deposited has to be suppressed. For this reason, it was inferior in abrasion resistance and could not provide a long service life.
[0004]
If a build-up roller is used instead of a high-chromium cast iron roller that causes such uneven wear and has a low material efficiency and a short life, the wear is suppressed by selecting the build-up wire, and uneven wear countermeasures can be taken. , The service life can be extended. As a countermeasure against uneven wear, since the outer diameter of the roller is constant, it is necessary to weld a thick build-up wire to a portion where wear is remarkable, and the base metal roller must be deeply cut off at that portion. Therefore, as compared with a crushed surface having less uneven wear, the undercut portion becomes deeper and a step is formed at a portion where the depth changes.
[0005]
[Problems to be solved by the invention]
However, in order to extend the service life of the roller made of high chromium cast iron, it is necessary to thicken a hard overlay wire having excellent wear resistance to a thickness of about 30 to 100 mm. In addition, the build-up cross section has a discontinuous cross-sectional shape in which a thick portion and a thin portion are adjacent to each other, and when a large amount of a hardened build-up wire is built up like a cement raw material mill roller, the build-up amount is about 2 to 3 tons. As a result, the residual stress due to the weld build-up becomes enormous, and the stress is concentrated on the step portion (discontinuous section) of the base metal roller, causing vibration and high surface pressure load during operation to be dragged. Thus, there was a risk that the base metal would be cracked or damaged.
[0006]
In addition, the hardfacing metal has a large number of cracks, so that the cracks easily propagate to the base metal. In addition, there is also a problem that the hardened metal is easily peeled off and dropped off from the roller body in order to thickly harden the hardened wire.
[0007]
An object of the present invention is to prevent cracking or breakage of base metal even when subjected to vibration during operation and high surface pressure load, and peeling or falling off of hardened metal, despite the presence of a discontinuous cross-sectional shape in the build-up cross section. An object of the present invention is to provide a crushing surface member that can be prevented.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a crushing surface member of the present invention is used in a crusher of a type in which a material is continuously bitten between opposing crushing surfaces and crushed, and the crushing surface is provided with an abrasion-resistant hardened metal. A crushing surface member in which the material is overlaid, and a base material surface of a portion that is significantly worn in a direction perpendicular to the crushing direction is provided with an undercut portion that is continuous in the crushing direction. It is made of a material having a lower abrasion resistance than the abrasion-resistant hardened metal material, and ribs having substantially the same height as the depth of the undercut portion are attached at predetermined intervals in the crushing direction. An abrasion-hardened metal material is build-up-filled, and a second abrasion-resistant hardened metal material is built-up on the entire crushed surface of the first abrasion-resistant hardened metal material.
[0009]
Large wear, such as a cement raw material grinding mill roller at a cement factory, with a build-up thickness of at least 30 mm or more. It is necessary to thicken the hardened metal on the base metal roller on the crushing surface, and to thinly build the hardened metal on the crushing surface which is not easily worn so as to match the abrasion rate and increase the use efficiency of the crusher member.
[0010]
In order to meet this requirement, since the outer diameter of the roller is constant, it is necessary to form different thick sections and thick sections on the base metal roller. A deep undercut results in a discontinuous cross-sectional shape on the build-up surface with the thin build-up portion. Concentrated stress is generated at the discontinuous section of the roller due to high grinding surface pressure and vibration during operation, and there is a danger that the roller body is cracked and the hardened metal is peeled off or falls off.
[0011]
As a simple countermeasure for preventing such cracking or breakage, the present inventor attaches low wear-resistant ribs only to the undercut portion of the base metal roller at predetermined intervals in the roller circumferential direction, and attaches adjacent ribs. A hard metal with high wear resistance is embedded between them. Since a large number of ribs having low wear resistance exist in the undercut portion, stress concentrated on the discontinuous portion is divided and dispersed, thereby preventing the base metal roller from being cracked or broken.
[0012]
Further, the carbide-precipitated alloy build-up wire, which frequently causes cracking, has excellent wear resistance, but is brittle, and tends to peel off when subjected to multilayer build-up. When a general overlaying method is used in which such an overlaying wire is wound around the outer peripheral surface of the roller from over 30 mm to 100 mm while being melted, the residual welding stress becomes enormous, and a fusion line between the base metal roller and the hardened metal is formed. Residual stress is concentrated on the resulting metallurgical discontinuity, and there is a danger that the hardened metal will peel off and fall off from the fusion line at a stretch. The critical build-up thickness that does not cause such peeling or falling off depends on the chemical composition of the wire used, but is preferably 50 mm or less. However, by applying the present invention, it is possible to form a thick building over 50 mm, and it is possible to avoid occurrence of peeling and falling off.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional front view and a longitudinal sectional side view of a crushing roller showing an embodiment of the present invention, and FIG. 2 is a partially broken elevational view of a vertical roller mill using the crushing roller.
[0014]
The crushing surface member of the present embodiment is a crushing roller used in a vertical roller mill. The vertical roller mill is used for crushing cement raw materials in a cement factory. As shown in FIG. 2, this vertical roller mill has three crushing rollers 10 arranged on a table 20 at equal intervals in a circumferential direction. The table 20 is rotationally driven by a lower drive mechanism 40. The pulverized raw material is put on the table 20 from the center of the mill. The pulverized raw material put on the central portion of the table 20 is driven away from the central portion by a centrifugal force caused by the rotation of the table 20 in the outer peripheral direction, and is bitten between the pulverizing rollers 10.
[0015]
The three crushing rollers 10, which are generally referred to as spherical rollers, rotate following the table 20 by frictional force and bite the crushed raw material repelled in the outer peripheral direction to crush. The required fineness is obtained by applying an appropriate surface pressure to each crushing roller 10 by the elastic mechanism 30. As described above, the surface pressure applied to the outer peripheral surface, which is the crushing surface of the crushing roller 10, is enormous.
[0016]
As shown in FIG. 1, each crushing roller 10 is formed by thickening a hardened metal 14 having excellent abrasion resistance to a different thickness in a width direction (roller axis direction) on an outer peripheral surface which is a crushing surface. It is a build-up roller. More specifically, the outer peripheral surface of the base metal roller 11 is an arc surface having a radius of curvature R curved in a roller axis direction perpendicular to the circumferential direction. A central portion in the width direction of the outer peripheral surface is undercut to substantially the same thickness in the width direction, and a rib 13 having substantially the same height as the depth D of the undercut portion 12 is provided in the undercut portion 12. Are arranged at predetermined intervals in the direction, and are fixed to the outer peripheral surface of the base metal roller 11.
[0017]
The ribs 13 are made of a material having lower abrasion resistance than the hardened metal 14, and the first hardened metal 14 a is filled between

adjacent ribs

13, 13. Thereby, the build-up in the undercut portion 12 is completed, and the surface and the base material surfaces on both sides become flush. Further, the second hardened metal 14b is built up to the target thickness on the entire outer peripheral surface of the base metal roller 11 from above the first hardened metal 14a.
[0018]
The first hardened metal 14a is built up by non-gas arc, carbon dioxide gas arc welding or the like using a flux-hardened hardfacing wire. The build-up of the second hardened metal 14b is performed by a method of winding a flux-hardened build-up welding wire around the outer peripheral surface of the roller while melting the same.
[0019]
By applying the two overlaying methods as described above, the unevenly worn portion where wear is remarkable is made thick, but in the undercut portion, a slit using a low abrasion-resistant rib is used. The welding method makes the welding residual stress generated by the thick build-up harmless. Further, the molten metal formed by the welding hardening wire is wound thereon to build up the hardened metal having a predetermined thickness distribution, thereby extending the life.
[0020]
A further feature is that after the circumferentially wrapped portion (the second hardened metal portion) is worn away, a slit built-up portion (the first hardened metal portion having ribs) appears, and the crushing ability that is decreasing is reduced. Due to the excellent biting properties of the slit overlay, the recovery is maintained again, and as a result, the crushing ability is maintained for the entire overlay thickness.
[0021]
As the material of the rib having low wear resistance, a plate such as a mild steel, a carbon steel, a 14% manganese steel, and a stainless steel is usually selected. These materials are the same as the base metal roller or have excellent toughness. The thickness of the rib is desirably 6 to 9 mm, and the height thereof is selected to be substantially the same as the undercut depth. The attachment interval of the rib is preferably 30 to 50 mm. These ribs are welded into the undercut. The welding hardfacing wire is filled and overlaid in the space surrounded by the adjacent ribs, and the underlaying of the undercut portion is completed.
[0022]
Assuming that no ribs (partition walls) are present, the welding residual stress is increased by a method in which the overlay wire is wound around the circumference of the roller. A weld fusion line that fuses with the working line to form a boundary is continuously formed on the roller circumference, and this fusion line forms a metallurgical discontinuity so that a stress concentration occurs at that portion. become. The metallurgical discontinuities can be explained by the fact that the base metal roller and the weld hardfacing wire are dissimilar materials, their physical properties are overwhelmingly different, and the hardfacing metal has numerous cracks. And the risk of the cracks propagating and leading to cracks or breakage of the roller material may increase. In particular, the thicker the deposited metal is, the greater the residual stress of welding increases, the higher the risk of crack propagation, and the more easily the hardened metal peels off and falls off the roller body at once. Therefore, the formation of continuous metallurgical discontinuities must be avoided in terms of stress concentration.
[0023]
From this point of view, ribs having low wear resistance, typically mild steel walls, are mounted on the circumference of the roller by a large number of welds at equal intervals, and the welding wall is formed in each space formed by the mild steel walls. Since the building is completed, the stress generation is confined and dispersed inside each block, so that the stress accumulation is greatly reduced as compared with the continuous building. Also, the stress accumulation is reduced from the viewpoint that the mild steel wall is deformed during the build-up and absorbs the welding residual stress.
[0024]
Low abrasion resistant ribs, typically mild steel walls, have the effect of breaking metallurgical discontinuities to prevent stress concentrations and reduce the repeated shear stress experienced by the crushed surfaces of the rollers during operation. It also absorbs and prevents the brittle weld metal from peeling off.
[0025]
In the roller circumferential winding overlay method, since a continuous overlay line is formed on the entire circumference of the roller, a metallurgical discontinuous line between the base metal and the weld overlay metal is formed on the entire circumference of the roller. become. Then, when the welding residual stress concentrates on that portion and a crack is once generated, the crack continues to propagate on the line and propagates until the welding residual stress is completely released.
[0026]
The effect of the ribs for preventing the base material crack and the hard metal from peeling, falling off, and breaking due to the concentrated stress is greater depending on (1) the plate thickness, (2) the number of attachments, (3) the height, and the like. to be influenced.
[0027]
(1) The thickness w of the rib is preferably in the range of 0.1 W ≦ w ≦ W, where W is the distance between adjacent ribs, that is, the length of the first hardened metal in the circumferential direction of the roller therebetween. For example, when W = 50 mm, the range of w is 5.0 mm to 50 mm. When w is increased, the effect of the reinforcing block of the roller material increases, which is very effective in preventing the roller material from being damaged. However, if the thickness is too large, the length of the wear-resistant hardened metal is reduced, and wear is promoted. If the size is too small, the effect as a reinforcing member is lost. The range of the thickness w which is actually most frequently applied is 6.0 to 12 mm.
[0028]
(2) The greater the number of attached ribs, the more effective it is in preventing the base material roller and the hardened metal from peeling and falling off, but the number of attached ribs is determined by the size of w and the size of W. From a practical point of view, the plate thickness w is in the range of 6 to 12 mm, and the size of W, that is, the length of the first hardened metal having excellent wear resistance, is in the range of 20 to 60 mm. However, in practice, the most frequently selected W is in the range of 30 to 50 mm. The number of sheets to be attached is determined by these two factors.
[0029]
(3) The height of the rib is the most effective factor for solving the two problems of cracking and breakage of the material roller and peeling and falling off of the hardfacing metal. When the thickness of the hardened metal is increased from 30 mm to 100 mm, according to the method of melting and winding the overlay wire in the circumferential direction of the roller, which is generally employed in the method of overlaying the roller, 50 mm is required. If the deposited metal is exceeded, there is a high risk of peeling and falling off from the boundary line with the roller base material to release stress at a stretch. The reason is that the properties of the material roller and the hardfacing metal are significantly different, so that a kind of metallurgical discontinuity is formed at the fusion line, and the welding residual stress generated by the multilayer overlaying is concentrated on that part. This causes cracks in the roller material, causing peeling and falling off of the hardfacing metal. In the case of a hardened build-up metal, if it exceeds 50 mm, there is a risk of peeling and falling off. However, cracks and shedding occurring on the material roller occurred when the thickness of the hardened metal was 30 mm or more.
[0030]
A) The thickness of the slit overlay (first hardened metal thickness) that can prevent the hardened overlay metal from falling off is shown in Table 1 in relation to the total hardened metal thickness. The limit thickness of the circumferentially wound overlay (first hardened metal) is 50 mm. As for the peeling and falling off of the hardened metal, if a thickness of 50 mm or more is given, this occurs. Therefore, the thickness of the slit overlay may be a thickness obtained by subtracting the peel thickness of 50 mm from the total thickness.
[0031]
[Table 1]

[0032]
B) Table 2 shows the slit overlay thickness (first hardened metal thickness) that can prevent cracking and breakage of the base metal in terms of the total hardened metal thickness. Regarding cracking and falling off of the base metal, the thickness of the hardened metal exceeds 30 mm. Therefore, the thickness of the slit for preventing cracking or breakage of the base material is at least 1/3 of the thickness of the entire hardened metal.
[0033]
[Table 2]

[0034]
Table 3 summarizes the ranges satisfying both conditions A) and B). By adopting the slit build-up thickness (first hardened metal thickness) described here, it is possible to prevent both the hardened build-up metal from falling off and the base metal from cracking and breaking. That is, the larger slit build-up thickness (first cured metal thickness), specifically, B) is adopted when the total cured metal thickness is less than 80 mm, and A) when the total cured metal thickness is 80 mm or more. By adopting this, it is possible to prevent both falling off of the hardfacing metal, cracking and breakage of the base metal.
[0035]
[Table 3]

[0036]
Conventionally, with respect to the overlay method in which a wire is melted and wound around a roller circumference, which is generally used, there is an increased risk that a part of the material roller is cracked when the thickness of the hardened metal is about 30 mm or more. Further, when the thickness of the hardened metal exceeds 50 mm or more, starting from a part of the crack and increasing the welding residual stress due to thickening by 20 mm, peeling and falling off at a stretch from the boundary with the hardened metal occur. did. This led to cracks growing to a distance where the welding residual stress was completely released and the balance was achieved, and the deposited metal during that time was peeled off and dropped off. According to the present embodiment, this is effectively prevented, and a hardened metal thickness of 30 mm or more, or even 50 mm or more, becomes possible.
[0037]
【Example】
An embodiment regarding slag and clinker crushing rollers in a cement factory will be described.
[0038]
The crusher is a vertical roller mill (FIG. 2) having a crushing capacity of 90 to 100 tons / hour per hour. The crushing roller (FIG. 1) is a giant roller weighing 7 to 10 tons, having a maximum diameter of about 2300 mm and a maximum width of about 700 mm. The thickness of the roller material is about 160 mm at the maximum diameter portion. The surface pressure applied to the crushing surface of the crushing roller is enormous, and if the cross-sectional shape of the hardened metal built up on the outer crushing surface becomes discontinuous, concentrated stress occurs at the discontinuous portion due to high surface load. The roller material cracks frequently. The cracks propagated vertically from numerous irregularities on the surface of the roller material, reaching a maximum depth of about 50 mm, and there was a risk of breakage. In some cases, substantially parallel peeling cracks were generated on the outer peripheral surface of the roller. The material of the base metal roach is cast steel, which is equivalent to JIS carbon steel cast steel product SC460.
[0039]
Particularly in the case of cast steel products, the crystal growth is directional and solidifies last. In applications where low-melting impurities easily accumulate at grain boundaries and are subjected to high surface pressure, there is a property that cracks and breakage are likely to occur along the grain boundaries.
[0040]
Under such circumstances, the slit method is applied to the undercut portion. The total thickness of the hardened metal was 60 mm, and a slit method using a rib was adopted from the surface of the base metal roller (the bottom surface of the undercut portion) to 35 mm. However, 5 mm below the back of 35 mm is a lower build layer and has no wear resistance. It is a build-up layer to prevent crack propagation.
[0041]
The rib was a mild steel wall, and the thickness w was 9 mm using a flat bar material of 9 mm. Its height is 35 mm as described above. 120 ribs were attached by welding at equal intervals of about 50 mm in an undercut portion having a depth of 35 mm formed at the center in the width direction of the roller material surface. The slit overlay between the ribs filling the undercut portion is an embedded overlay using an SB-0 wire.
[0042]
After completion of the slit overlay, the SB-0 wire was wound around the entire outer peripheral surface of the roller including the slit overlay while being melted to a thickness of about 25 mm. The chemical composition of the SB-0 wire is C: 4.5%, Cr: 22%, Nb: 7.0%, Mo: 2.0%, V: 1.5%, the hardness is HV750-850, and the abrasion is The coefficient is between 2.8 and 4.0.
[0043]
Conventionally, this type of crushing roller, in order to impart abrasion resistance, has been carrying out a method of overlaying winding around the roller with a high chrome cast iron-based wire including an undercut portion, but from the start of use about 2,2 Cracking of the base metal roller and peeling and falling off of the hardened metal occurred in 2,000 hours, and had to be replaced. However, the roller of the present example did not cause peeling of the hardened metal or cracking of the roller material even after about 4,000 to 6,000 hours had passed.
[0044]
【The invention's effect】
As described above, the crushing surface member of the present invention has a huge size such as a cement raw material crushing mill roller in a cement factory, and the crushing of a roller crusher that performs a thick build-up with a build-up thickness of at least 30 mm or more. Regarding the build-up of rollers and crushing tables, hardened build-up metal is thickened on the base metal roller on the crushed surface that receives local wear, and the wear speed is matched by thinly building up the crushed surface that is less susceptible to wear. In the case where the use efficiency of the pulverizer member is to be increased, the high pulverization during operation is performed at the discontinuous portion having a discontinuous cross-sectional shape formed between the thick underlay portion and the thin underlay portion which are deeply undercut. Cracking of the base metal roller and peeling and falling off of the hardened metal due to the occurrence of concentrated stress due to surface pressure and vibration can be effectively prevented by a simple construction method. As a result, it is possible to increase the thickness to a thickness exceeding 50 mm, and together with preventing the base metal roller from cracking, preventing the hardened metal from peeling off and falling off, it is possible to realize a much longer service life than before.
[Brief description of the drawings]
FIG. 1A is a longitudinal sectional front view of a crushing roller showing an embodiment of the present invention, and FIG. 1B is a sectional view taken along line AA in FIG. FIG.
FIG. 2 is a partially broken elevation view of a vertical roller mill using the grinding roller.
[Explanation of symbols]
REFERENCE SIGNS LIST 10 grinding roller 11 base metal roller 12 undercut 13 rib 14 hardened metal 20 table

Claims

A crushing surface member that is used in a crusher of a type in which a material is continuously bitten between opposing crushing surfaces and crushes, and the crushing surface is overlaid with an abrasion-resistant hardened metal material. The base material surface of a portion which receives significant wear in a direction perpendicular to the base material is provided with an undercut portion which is continuous in the crushing direction, and the undercut portion has a lower wear resistance than the wear-resistant hardened metal material. And ribs having substantially the same height as the depth of the undercut portion are attached at predetermined intervals in the crushing direction, and a first abrasion-resistant hardened metal material is padded between adjacent ribs to form a first rib. A crushing surface member, wherein a second wear-resistant hardened metal material is built up over the entire crushing surface from above the wear-resistant hardened metal material.