JPH0436447A - Production of hot-dip metal-coated steel sheet - Google Patents
Production of hot-dip metal-coated steel sheetInfo
- Publication number
- JPH0436447A JPH0436447A JP13968390A JP13968390A JPH0436447A JP H0436447 A JPH0436447 A JP H0436447A JP 13968390 A JP13968390 A JP 13968390A JP 13968390 A JP13968390 A JP 13968390A JP H0436447 A JPH0436447 A JP H0436447A
- Authority
- JP
- Japan
- Prior art keywords
- steel sheet
- plated
- steel plate
- opening
- hot
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 124
- 239000010959 steel Substances 0.000 title claims abstract description 124
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 34
- 239000002184 metal Substances 0.000 title claims abstract description 34
- 238000004519 manufacturing process Methods 0.000 title claims description 14
- 238000007747 plating Methods 0.000 claims abstract description 27
- 238000000034 method Methods 0.000 claims description 19
- 230000001590 oxidative effect Effects 0.000 claims description 19
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- 229910052739 hydrogen Inorganic materials 0.000 claims description 4
- 239000001257 hydrogen Substances 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 125000004435 hydrogen atom Chemical class [H]* 0.000 claims 1
- 229910052725 zinc Inorganic materials 0.000 abstract description 89
- 239000011701 zinc Substances 0.000 abstract description 89
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 abstract description 88
- 229910052582 BN Inorganic materials 0.000 abstract description 6
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 abstract description 6
- 238000007789 sealing Methods 0.000 abstract description 5
- 230000015572 biosynthetic process Effects 0.000 abstract description 3
- 239000011248 coating agent Substances 0.000 abstract description 3
- 238000000576 coating method Methods 0.000 abstract description 3
- 230000001105 regulatory effect Effects 0.000 abstract 2
- 229910001335 Galvanized steel Inorganic materials 0.000 description 13
- 239000008397 galvanized steel Substances 0.000 description 13
- 239000007789 gas Substances 0.000 description 8
- 230000007547 defect Effects 0.000 description 5
- 210000003128 head Anatomy 0.000 description 5
- 238000005246 galvanizing Methods 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 238000007598 dipping method Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 238000000137 annealing Methods 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 210000004894 snout Anatomy 0.000 description 2
- 230000002459 sustained effect Effects 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 229910001297 Zn alloy Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 230000005499 meniscus Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000004382 potting Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 239000007779 soft material Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野１
本発明は、溶融亜鉛めっき鋼板および合金化溶融亜鉛め
っき鋼板などの溶融金属めっき鋼板を連続的に製造する
方法に関するものであって、殊に溶融亜鉛（溶融亜鉛合
金を含む。以下同じ）を薄鋼板表面上に連続的に、安定
にめっきするための操業性に優れためつき鋼板の製造方
法に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a method for continuously producing hot-dip metal-coated steel sheets such as hot-dip galvanized steel sheets and alloyed hot-dip galvanized steel sheets. The present invention relates to a method for manufacturing a hot-dipped steel sheet with excellent operability, for continuously and stably plating molten zinc (including molten zinc alloy; the same applies hereinafter) on the surface of a thin steel sheet.
［従来の技術Ｊ
溶融亜鉛めっき鋼板は耐食性に優れ、また比較的安価で
あることから建材及び家電の分野では広く用いられてい
る。また合金化溶融亜鉛めっき鋼板は耐食性に優れると
ともに、加工度の大きいプレス加工にも耐えられること
から、自動車用鋼板としての需要が近年急速に拡大して
いる。[Prior Art J Hot-dip galvanized steel sheets have excellent corrosion resistance and are relatively inexpensive, so they are widely used in the fields of building materials and home appliances. In addition, alloyed hot-dip galvanized steel sheets have excellent corrosion resistance and can withstand heavy press working, so their demand as steel sheets for automobiles has increased rapidly in recent years.
溶融亜鉛めっき鋼板及び合金化溶融亜鉛めっき鋼板の一
般的な製造方法は次のようなものである。すなわち冷間
圧延後の薄鋼板を前処理工程で表面を清浄化してから、
無酸化性あるいは還元性の雰囲気中で焼鈍することによ
って表面酸化膜を除去し、次いで鋼板を酸化させること
なく冷却して、はぼ亜鉛浴の温度まで板温を下げてから
亜鉛洛中に侵入させる。亜鉛浴中で鋼板面に付着した過
剰の溶融亜鉛をガスワイパーで除去して亜鉛目付量を調
整し、そのまま冷却したものが溶融亜鉛めっき鋼板であ
り、溶融亜鉛目付量を調整してから、さらに亜鉛めっき
層の合金化のための加熱処理を施したものが合金化溶融
亜鉛めっき鋼板である。A general method for manufacturing hot-dip galvanized steel sheets and alloyed hot-dip galvanized steel sheets is as follows. In other words, after cleaning the surface of the thin steel plate after cold rolling in a pretreatment process,
The surface oxide film is removed by annealing in a non-oxidizing or reducing atmosphere, and then the steel sheet is cooled without oxidizing to lower the sheet temperature to the temperature of the zinc bath before entering the zinc bath. . Hot-dip galvanized steel sheets are produced by removing excess molten zinc that adhered to the surface of the steel sheet with a gas wiper in a zinc bath to adjust the zinc coating weight, and cooling it as is.After adjusting the molten zinc coating weight, Alloyed hot-dip galvanized steel sheets are those that have undergone heat treatment to alloy the galvanized layer.
従来型のジンクロールを有する溶融亜鉛めっき装置を第
３図に示す。鋼板２はスナウト１１から亜鉛浴６中に引
き込まれ、ジンクロール１０に巻きついで鉛直方向に引
上げられる。亜鉛浴中のジンクロールｌＯは、溶融亜鉛
の付着した鋼板２の通板を垂直方向に方向変換させるこ
とによって、鋼板面上の溶融亜鉛が凝固するまでロール
に無接触で鋼板２を搬送して、擦り疵などの表面欠陥の
発生を防止するための重要な装置である。なお、３はサ
ポートロール、７はガスワイパーである。A hot-dip galvanizing apparatus with a conventional zinc roll is shown in FIG. The steel plate 2 is drawn into the zinc bath 6 through the snout 11, wrapped around a zinc roll 10, and pulled up in the vertical direction. The zinc roll lO in the zinc bath is produced by conveying the steel plate 2 without contacting the rolls until the molten zinc on the surface of the steel plate solidifies by changing the direction of the steel plate 2 to which molten zinc has adhered in the vertical direction. This is an important device for preventing the occurrence of surface defects such as scratches. Note that 3 is a support roll and 7 is a gas wiper.
ジンクロール１０は約４６０℃の溶融亜鉛浴６中に常時
保持されるので、耐溶損性に優れでいることが必要なの
は当然である。ジンクロール１０表面に付着物が形成さ
れると、鋼板面に押し疵を作ったり、付着物が鋼板面に
移行し表面欠陥となることがある。また多くの場合、ジ
ンクロールＩＯは駆動系を有しないので、鋼板がスリッ
プしてジンクロールｌＯの回転が不連続になると、鋼板
面には擦り疵を形成することになる。さらに、長時間に
わたってめっき操業を続けるとジンクロール表面には凹
凸ができるので、亜鉛浴から取り出して手入れを行う必
要があるなど、浴中機器の存在のために操業性が悪くな
る欠点があった。Since the zinc roll 10 is constantly kept in the molten zinc bath 6 at about 460°C, it is natural that it must have excellent erosion resistance. When deposits are formed on the surface of the zinc roll 10, they may cause scratches on the surface of the steel plate, or the deposits may migrate to the surface of the steel plate, resulting in surface defects. Further, in many cases, the zinc roll IO does not have a drive system, so if the steel plate slips and the rotation of the zinc roll IO becomes discontinuous, scratches will be formed on the steel plate surface. Furthermore, if plating operations are continued for a long period of time, the surface of the zinc roll becomes uneven, so it is necessary to take it out of the zinc bath and clean it, and the presence of equipment in the bath reduces operability. .
またジンクロールなどの浴中機器の存在のために溶融亜
鉛の容器は極めて大きくなり、溶融亜鉛量が多くなるこ
とから、めっき種類の変更などに際して自由度が小さく
なるというような問題があった。このような問題を解決
するために、これまでにもジンクロールを使わない方法
が提案されてきた。Furthermore, due to the presence of in-bath equipment such as zinc rolls, the container for molten zinc becomes extremely large, and the amount of molten zinc increases, resulting in a problem that the degree of freedom in changing the type of plating is reduced. In order to solve these problems, methods that do not use zinc roll have been proposed.
ロールコータ法、メニスカス法及びカーテンフロー法な
どが代表的なジンクロールレス型の溶融めっき方法であ
る。しかし、これらは片面めっきには適しているが、鋼
板の両面に溶融めっきを施す場合には、めっき前の熱処
理が重複し鋼板の機械的性質を確保できないから適切な
めっき方法ではない。The roll coater method, the meniscus method, the curtain flow method, and the like are typical zinc roll-less hot-dip plating methods. However, although these are suitable for single-sided plating, they are not appropriate plating methods when hot-dipping both sides of a steel plate because the heat treatment before plating is redundant and the mechanical properties of the steel plate cannot be ensured.
ジンクロールを使わずに、また両面めっきにも通用が可
能な方法として空中ポットが提案されている。すなわち
溶融亜鉛を比較的小さな容器に保持し、容器の底部から
鋼板を侵入させて、溶融亜鉛を鋼板面に付着させる製造
方法である。この製造方法における眼目は鋼板が侵入す
る容器底部での溶融亜鉛の漏出を防止する手段と、鋼板
に付着する過剰の溶融亜鉛を除去する手段にある。Aerial potting has been proposed as a method that does not require the use of zinc rolls and is also applicable to double-sided plating. That is, this is a manufacturing method in which molten zinc is held in a relatively small container, a steel plate is introduced from the bottom of the container, and the molten zinc is adhered to the surface of the steel plate. The key points in this manufacturing method are a means for preventing leakage of molten zinc at the bottom of the container into which the steel plate enters, and a means for removing excess molten zinc adhering to the steel plate.
特開昭６３−１０９１４９号公報や特開昭６３−３１０
９４９号公報では容器底部での亜鉛浴の保持に電磁力を
利用しており、特開昭６３−１０９１４８号公報や特開
昭６３−３０３０４５号公報では容器底部での亜鉛浴の
保持に電磁力と静圧シールを併用している。電磁力をう
まく使うことができれば鋼板面への機械的な接触がない
ので、鋼板表面に欠陥を生成することもなく理想的な装
置となるが、溶融亜鉛の流出を完全に抑えようとすると
、励磁電源の容量がきわめて太き（なるばかりでなく、
磁力によって鋼板に吸弓力や反発力が作用するため鋼板
の安定な通板を損なう問題があった。また特開昭６３−
１６２８４７号公報や特開平１−１３９７４４号公報で
は鋼板をシールロール間に挟持して、溶融金属の流出を
抑える方法を提案しているが、シールロール表面に付着
物が堆積し、鋼板面に疵をつける問題があった。さらに
、本出願人は、特願平２−９７７７８号で、鋼板との間
にわずかの隙間をあけてシール板を配置し、溶融金属の
表面張力と移動する鋼板面での粘性流を利用して溶融金
属の流出を抑える手段を提案している。しかし、被めっ
き鋼板とシール板との隙間が大きくなった場合でも、鋼
板の通板が不安定に変動した場合でも容器底部の開口部
から溶融亜鉛の漏出を生じないような技術が必要とされ
るのはいうまでもない。JP-A-63-109149 and JP-A-63-310
No. 949 uses electromagnetic force to hold the zinc bath at the bottom of the container, and JP-A-63-109148 and JP-A-63-303045 use electromagnetic force to hold the zinc bath at the bottom of the container. and static pressure seals are used together. If electromagnetic force can be used effectively, there will be no mechanical contact with the surface of the steel plate, so it will not create defects on the surface of the steel plate, making it an ideal device.However, if you try to completely suppress the outflow of molten zinc, The capacity of the excitation power supply is extremely large (not only
There is a problem in that the stable threading of the steel plate is impaired because the magnetic force causes bow absorption and repulsive force to act on the steel plate. Also, JP-A-63-
162847 and JP-A-1-139744 propose a method of suppressing the outflow of molten metal by sandwiching a steel plate between seal rolls, but deposits accumulate on the seal roll surface and cause scratches on the steel plate surface. There was a problem with attaching the . Furthermore, in Japanese Patent Application No. 2-97778, the applicant placed a seal plate with a slight gap between it and the steel plate, and utilized the surface tension of the molten metal and the viscous flow on the surface of the moving steel plate. We are proposing a method to suppress the outflow of molten metal. However, even if the gap between the steel plate to be plated and the seal plate becomes large, or the threading of the steel plate fluctuates unstablely, a technology is needed that will prevent molten zinc from leaking from the opening at the bottom of the container. Needless to say,
［発明が解決しようとする課題］
溶融亜鉛めっき鋼板及び合金化溶融亜鉛めっき鋼板の製
造に際して、亜鉛浴周辺での従来技術における問題点を
検討した結果、本発明ではジンクロールを省略しながら
両面めっきすることを目標にして、空中ポットを製造装
置として採用することとした。空中ポットにおける重要
課題である容器底部での溶融亜鉛の漏出防止方法として
、本発明では次のような方法を提案する。[Problems to be Solved by the Invention] As a result of studying the problems in the conventional technology around the zinc bath when manufacturing hot-dip galvanized steel sheets and alloyed hot-dip galvanized steel sheets, the present invention has solved the problem of double-sided plating while omitting the zinc roll. With this goal in mind, we decided to use an aerial pot as the manufacturing device. The present invention proposes the following method to prevent leakage of molten zinc from the bottom of the container, which is an important issue in aerial pots.
［課題を解決するための手段］
本発明は、溶融めっき金属浴を保持した容器の底部の開
口部から被めっき鋼板を連続的に該浴中に侵入させた後
、めっき金属層の付着した鋼板を該浴の上方に引き上げ
、ついで余剰のめつき金属を払拭して溶融金属めっき鋼
板を製造するにあたり、
前記容器の開口部に設けられるシール板の開口の鋼板厚
さ方向の寸法を被めっき鋼板厚さより大きくすると共に
、すくなくとも被めっき鋼板の侵入する容器底部の開口
部近傍の溶融金属の表面張力を大きくする手段を講じて
、該シール板と被めっき鋼板の間隙から溶融金属の漏洩
を防止しながらめっきを行うことを特徴とする。[Means for Solving the Problems] The present invention involves continuously introducing a steel plate to be plated into a hot-dip metal bath through an opening at the bottom of a container holding a hot-dipping metal bath, and then removing a steel plate with a plated metal layer attached thereto. When manufacturing a hot-dip metal-plated steel sheet by lifting the metal above the bath and then wiping off the excess plating metal, the dimensions of the opening of the seal plate provided at the opening of the container in the thickness direction of the steel sheet are the dimensions of the plated steel sheet. In addition to increasing the surface tension of the molten metal near the opening at the bottom of the container into which the steel plate to be plated enters, prevent the leakage of molten metal from the gap between the seal plate and the steel plate to be plated. It is characterized by performing plating while
この場合、溶融金属の表面張力を大きくする手段は、被
めっき鋼板の侵入する容器底部の開口部外部周辺の雰囲
気を溶融金属に対して酸化性とすることによるのがよい
。In this case, the means for increasing the surface tension of the molten metal is preferably to make the atmosphere around the outside of the opening at the bottom of the container into which the steel plate to be plated enters oxidizing to the molten metal.
被めっき鋼板の侵入する容器底部の開口部外部周辺の雰
囲気が溶融金属に対して酸化性であり、かつ被めっき鋼
板に対しては非酸化性とするのが層好ましい。It is most preferable that the atmosphere around the outside of the opening at the bottom of the container into which the steel plate to be plated enters is oxidizing to the molten metal and non-oxidizing to the steel plate to be plated.
また、被めっき鋼板の侵入する容器底部の開口部外部周
辺の雰囲気として具体的には、実質的に水素、窒素およ
び水蒸気の混合雰囲気を使用するのが有利である。Further, specifically, it is advantageous to use a mixed atmosphere of substantially hydrogen, nitrogen, and water vapor as the atmosphere around the outside of the opening at the bottom of the container into which the steel sheet to be plated enters.
〔作用］
本発明の作用についで次に説明する。第１図は本発明を
好適に実施できる装置を示したものである。本発明では
溶融亜鉛の容器として、第１図に示すような空中ポット
８を用いる。すなわち溶融亜鉛浴６を保持する容器の底
部９の開口部４から、デフレクタロールｌで進行方向を
変化させサポートロール３で支持した鋼板２をシール板
５を介して連続的に侵入させ、鋼板面に溶融亜鉛を付着
させてからほぼ垂直方向に通板し、亜鉛浴６上方に設け
たガスワイパー７によって鋼板面に付着した過剰の溶融
亜鉛を除去して亜鉛めっき鋼板を製造するのであるが、
本発明では、容器の底部９に固定したシール板５と鋼板
２は無接触としている。すなわち、シール板５と鋼板２
との間に微小隙間を有する固定式のシール板を用いてい
るので鋼板面に表面疵を生しることはない。然もシル板
５と鋼板２の間から溶融亜鉛の漏出を防止している。溶
融亜鉛の漏出防止には、鋼板が侵入する容器底部の開口
部近傍の溶融亜鉛の表面張力を高くする、或は鋼板が侵
入する容器底部９の開口外部周辺を溶融亜鉛にとって酸
化性雰囲気にする方法を採っている。[Function] The function of the present invention will be explained next. FIG. 1 shows an apparatus that can suitably carry out the present invention. In the present invention, an aerial pot 8 as shown in FIG. 1 is used as a container for molten zinc. That is, the steel plate 2 supported by the support rolls 3 is continuously introduced through the opening 4 of the bottom 9 of the container holding the molten zinc bath 6 through the seal plate 5 by changing the traveling direction with the deflector roll l, and the steel plate surface is After depositing molten zinc on the steel sheet, the sheet is passed in a nearly vertical direction, and a gas wiper 7 installed above the zinc bath 6 removes excess molten zinc adhering to the surface of the steel sheet to produce a galvanized steel sheet.
In the present invention, the seal plate 5 fixed to the bottom 9 of the container and the steel plate 2 are not in contact with each other. That is, the seal plate 5 and the steel plate 2
Since a fixed seal plate with a small gap between the steel plate and the steel plate is used, there will be no surface flaws on the steel plate surface. Moreover, leakage of molten zinc from between the sill plate 5 and the steel plate 2 is prevented. To prevent leakage of molten zinc, increase the surface tension of the molten zinc near the opening at the bottom of the container where the steel plate enters, or create an oxidizing atmosphere for molten zinc around the outside of the opening at the bottom 9 of the container where the steel plate enters. method is adopted.
しかしながら、実操業においては、シール板５と鋼板２
との間の適切な隙間を長時間にわたって安定に維持し、
シール板５と鋼板２とを無接触とすることは容易でない
。シール板５と鋼板２が接触してしまっては鋼板面に表
面疵を生じてしまうので、表面疵の発生を恐れるあまり
シール板と鋼板との隙間を大きくとり過ぎたり、鋼板の
通板が不安定に変動した場合には第２図（ａ）に示すよ
うにシール板５と鋼板２との隙間に溶融亜鉛が垂れ下が
り、容器底部の開口部から溶融亜鉛が漏出することがあ
った。However, in actual operation, the seal plate 5 and the steel plate 2
Stably maintains an appropriate gap between the
It is not easy to make the seal plate 5 and the steel plate 2 non-contact. If the seal plate 5 and the steel plate 2 come into contact, surface flaws will occur on the surface of the steel plate, so for fear of surface flaws, do not leave too large a gap between the seal plate and the steel plate, or do not thread the steel plate properly. When the temperature fluctuates stably, molten zinc hangs down into the gap between the seal plate 5 and the steel plate 2, as shown in FIG. 2(a), and sometimes leaks from the opening at the bottom of the container.
ところで、シール板と鋼板との隙間における溶融亜鉛の
保持は、主として溶融亜鉛の表面張力を利用するもので
ある。そこで、容器底部の開口部からの溶融亜鉛の漏出
をより確実に抑制するために、消融亜鉛面での表面張力
をさらに増大させる方法を検討した。By the way, the retention of molten zinc in the gap between the seal plate and the steel plate mainly utilizes the surface tension of the molten zinc. Therefore, in order to more reliably suppress the leakage of molten zinc from the opening at the bottom of the container, we investigated a method of further increasing the surface tension on the molten zinc surface.
しかし、溶融めっき金属浴の組成は基本的にめっき特性
の観点から決められるものであって、組成変更の自由度
は殆どない。溶融金属の物性についで詳細な検討を進め
たところ、溶融金属の最表層を酸化させることによって
液滴の表面張力は顕著に増大することを知見するに到っ
た。However, the composition of the hot-dip plating metal bath is basically determined from the viewpoint of plating characteristics, and there is almost no degree of freedom in changing the composition. After conducting a detailed study on the physical properties of molten metal, we discovered that the surface tension of droplets increases significantly by oxidizing the outermost layer of molten metal.
そこで、被めっき鋼板の侵入する容器底部の開口外部周
辺を溶融亜鉛にとって酸化性雰囲気にしたところ、第２
図（ｂ）に示すように、シール板５と鋼板２との隙間に
は溶融亜鉛の侵入は殆どなくなり、容器底部の開口部か
ら溶融亜鉛の漏出を解消することができた。しかし、空
中ポットに侵入するまでの溶融亜鉛の雰囲気の酸化性が
高すぎて被めっき鋼板表面を酸化する場合には、鋼板が
溶融亜鉛浴に浸漬されても局部的な不めっきの生じるこ
とがあった。Therefore, we created an oxidizing atmosphere for molten zinc around the outside of the opening at the bottom of the container through which the steel sheets to be plated entered.
As shown in Figure (b), almost no molten zinc entered the gap between the seal plate 5 and the steel plate 2, and leakage of molten zinc from the opening at the bottom of the container could be eliminated. However, if the oxidizing nature of the molten zinc atmosphere before it enters the aerial pot is too high and oxidizes the surface of the steel plate to be plated, local unplating may occur even if the steel plate is immersed in the molten zinc bath. there were.
被めっき鋼板の侵入する容器底部の開口外部周辺の雰囲
気についでさらに検討を進めた結果、（８融めっき金属
にとって酸化性雰囲気であると共に、被めっき鋼板にと
っては、非酸化性雰囲気であることがシール板と鋼板と
の隙間からの溶融亜鉛の漏出防止と、良好なめっき特性
を確保する上で極めて有効であることが分った。As a result of further investigation into the atmosphere around the outside of the opening at the bottom of the container through which the steel plate to be plated enters, we found that (8) it is an oxidizing atmosphere for the dipping metal, and a non-oxidizing atmosphere for the steel plate to be plated. It was found that this method is extremely effective in preventing leakage of molten zinc from the gap between the seal plate and the steel plate and ensuring good plating properties.
さらに、無酸化性或は還元性の雰囲気中で焼鈍すること
によって表面酸化膜を除去し、次いで鋼板を酸化させる
ことなく冷却して、はぼ曲鉛浴の温度まで板温を下げる
焼鈍炉側の雰囲気との整合性を考慮すると、被めっき鋼
板の侵入する容器底部の開口外部周辺は実質的に水素、
窒素および水蒸気の混合雰囲気であって、かつ、溶融亜
鉛にとって酸化性雰囲気であると共に、被めっき鋼板に
とっては非酸化性雰囲気であることが有利であることも
分った。Furthermore, the surface oxide film is removed by annealing in a non-oxidizing or reducing atmosphere, and then the steel plate is cooled without oxidizing to lower the plate temperature to the temperature of the curved lead bath. Considering the compatibility with the atmosphere, hydrogen and
It has also been found that it is advantageous to have a mixed atmosphere of nitrogen and water vapor, an oxidizing atmosphere for the molten zinc, and a non-oxidizing atmosphere for the steel sheet to be plated.
なお、ここでいう非酸化性とは、操業時において被めっ
き鋼板表面に不めっきの発生する程の酸化膜が実質上形
成されないことを意味する。Note that the term "non-oxidizing" as used herein means that an oxide film to the extent that no plating occurs is substantially not formed on the surface of the steel sheet to be plated during operation.
一方ガスワイパーにはＮ２ガスなどの不活性ガスを用い
ることによって、溶融亜鉛の酸化を抑制し酸化物系のド
ロスの発生を防止することが可能である。なお、使用す
る空中ポットにおいては、ヘッド高さが低く容量が小さ
いので、亜鉛溶解炉を空中ポットの傍に設けて、鋼板の
めっきによる溶融亜鉛の消費量を補給しヘッド高さを操
業中は一定に維持することが必要である。On the other hand, by using an inert gas such as N2 gas in the gas wiper, it is possible to suppress the oxidation of molten zinc and prevent the generation of oxide-based dross. Since the aerial pot used has a low head height and small capacity, a zinc melting furnace is installed next to the aerial pot to replenish the amount of molten zinc consumed by plating steel sheets and to maintain the head height during operation. It is necessary to maintain it constant.
空中ポットにおける重要なポイントは容器の底部９に固
定したシール板５と連続的に移動する鋼板２との隙間で
あって、シール板５と鋼板２は無接触状態にあり、かつ
溶融亜鉛が漏洩しない隙間を有することが必要である。An important point in the aerial pot is the gap between the seal plate 5 fixed to the bottom 9 of the container and the continuously moving steel plate 2, and the seal plate 5 and steel plate 2 are in a non-contact state and molten zinc leaks. It is necessary to have no gaps.
この隙間を０．０５〜１ｍｍにすると、溶融亜鉛の表面
張力による支持と鋼板が垂直上方向に移動する作用とに
よって、容器底部９に固定したシール板５と連続的に移
動する鋼板２との隙間から溶融亜鉛が下方番ご流出する
ことはない。この隙間がＣＩ ０５ ｍ ｍ以下になる
と、鋼板とシール板との接触が頻繁に発生して。When this gap is set to 0.05 to 1 mm, the sealing plate 5 fixed to the container bottom 9 and the continuously moving steel plate 2 are connected by the surface tension of the molten zinc and the vertical movement of the steel plate. Molten zinc will not flow downward from the gap. If this gap becomes less than CI 05 mm, contact between the steel plate and the seal plate will occur frequently.
鋼板面に疵をつけ表面欠陥を形成するこヒになる。一方
、この隙間が１ｍｍ以上になると、鋼板が垂直方向に移
動したとしでも、容器底部９に固定したシール板５と連
続的に移動する鋼板２との隙間から溶融亜鉛が漏出する
ので好ましくない。This can cause scratches on the steel plate surface and form surface defects. On the other hand, if this gap is 1 mm or more, even if the steel plate moves in the vertical direction, molten zinc will leak from the gap between the seal plate 5 fixed to the container bottom 9 and the continuously moving steel plate 2, which is not preferable.
また本発明の空中ポットにおけるシール板の材質として
、窒化硼素、グラファイト、及び窒化珪素・窒化硼素、
炭化珪素・窒化硼素、アルミナ・グラファイトなどのセ
ラミックスを正体とする焼結体及び複合焼結体を用いる
ことができる。これらの材料は溶融亜鉛に対する耐溶損
性に優れているばかりでなく、耐熱衝撃性にも優れてい
ることと具体的な実験結果から取捨選択したものであり
、いずれも実用性のあることを確認しである。Further, as the material of the seal plate in the aerial pot of the present invention, boron nitride, graphite, silicon nitride/boron nitride,
Sintered bodies and composite sintered bodies made of ceramics such as silicon carbide, boron nitride, alumina, and graphite can be used. These materials were selected based on the fact that they not only have excellent corrosion resistance against molten zinc but also excellent thermal shock resistance and specific experimental results, and we confirmed that they are all practical. It is.
ここで比較的軟質のセラミックスをシール板の素材とし
て用いることによって、鋼板面の疵付きを極力防止する
ことができる。製造開始段階における容器底部９に固定
したシール板５と連続的に移動する鋼板２との隙間が狭
すぎたとしても、上記したようにシール板を軟質な材料
にすることによって、適切な隙間が得られるまでシール
板５は連続的に移動する鋼板２により削り取られること
になる。By using relatively soft ceramics as the material for the seal plate, it is possible to prevent scratches on the surface of the steel plate as much as possible. Even if the gap between the seal plate 5 fixed to the container bottom 9 and the continuously moving steel plate 2 is too narrow at the start of production, by making the seal plate a soft material as described above, an appropriate gap can be created. The sealing plate 5 will be scraped away by the continuously moving steel plate 2 until it is obtained.
［実施例１ 次に実施例に基づいて本発明を説明する。[Example 1 Next, the present invention will be explained based on examples.
（実施例１）
第１図に示す空中ボット８において、シール板５の鋼板
面側を窒化硼素製とし、またシール板５と鋼板２との隙
間を０．７ ｍ ｍ、シール板５の先端における亜鉛浴
６のヘッド高さを８０ｍｍ、溶融亜鉛浴温を４６５℃、
および容器底部の開口外部周辺の雰囲気を露点１０℃の
２５％Ｈ２＋７５％Ｎ２とした状態において、還元性雰
囲気中で焼鈍してから、４６５℃まで冷却した板幅３０
０ｍｍの薄鋼板を５０ｍ／分のライン速度で通板した。(Example 1) In the aerial bot 8 shown in FIG. 1, the steel plate side of the seal plate 5 is made of boron nitride, and the gap between the seal plate 5 and the steel plate 2 is 0.7 mm, and the tip of the seal plate 5 is made of boron nitride. The head height of the zinc bath 6 was 80 mm, the molten zinc bath temperature was 465°C,
Then, under the condition that the atmosphere around the outside of the opening at the bottom of the container was 25% H2 + 75% N2 with a dew point of 10°C, the board was annealed in a reducing atmosphere and then cooled to 465°C.
A 0 mm thin steel plate was threaded at a line speed of 50 m/min.
Ｎ２ガスワイパーによって溶融亜鉛の付着量を５０ ｇ
／ ｍ ’に制御したところ、容器底部の開口部４近
傍の溶融亜鉛表面には酸化膜が形成されて表面張力が増
大し、かつ、めっき直前の鋼板上に実質上問題となる酸
化膜の形成はな（、しかも開口部４から溶融亜鉛の漏出
することはなく、安定なめっき操業を持続することがで
きた。The amount of molten zinc deposited was reduced to 50 g using an N2 gas wiper.
/ m', an oxide film is formed on the surface of the molten zinc near the opening 4 at the bottom of the container, increasing the surface tension, and the formation of an oxide film on the steel plate immediately before plating, which is a practical problem. Moreover, there was no leakage of molten zinc from the opening 4, and a stable plating operation could be maintained.
（実施例２）
容器底部の開口外部周辺の雰囲気を露点０℃の１５％Ｈ
２＋８５％Ｎ２とする他は実施例１と同様な操業条件に
して実施した。(Example 2) The atmosphere around the outside of the opening at the bottom of the container was 15% H with a dew point of 0°C.
The operation was carried out under the same operating conditions as in Example 1 except that the N2 was changed to 2+85% N2.
その結果、容器底部の開口部４近傍の溶融亜鉛表面には
酸化膜が形成されて表面張力が増大し、かつ、めっき直
前の鋼板上に実質上問題となる酸化膜の形成はなく、し
かも開口部４から溶融亜鉛の漏出することはなく、安定
なめっき操業を持続することができた。As a result, an oxide film is formed on the surface of the molten zinc in the vicinity of the opening 4 at the bottom of the container, increasing the surface tension, and there is virtually no formation of a problematic oxide film on the steel plate just before plating. There was no leakage of molten zinc from section 4, and stable plating operations could be maintained.
（実施例３）
容器底部の開口外部周辺の雰囲気を露点２０℃の２５％
Ｈ２＋７５％Ｎ２．シール板５と鋼板２との間隔を１．
０ ｍ ｍ、シール板５の先端における亜鉛浴６のヘッ
ド高さを３０ｍｍ、板幅３００ｍｍの薄鋼板のライン速
度を８０ｍ／分のライン速度とする他は実施例Ｉと同様
な操業条件にしたところ、容器底部の開口部４から溶融
亜鉛の漏出することはなく、安定なめっき操業を持続す
ることができた。(Example 3) The atmosphere around the outside of the opening at the bottom of the container was set to 25% of the dew point of 20°C.
H2+75%N2. The distance between the seal plate 5 and the steel plate 2 is set to 1.
The operating conditions were the same as in Example I, except that the head height of the zinc bath 6 at the tip of the seal plate 5 was 30 mm, and the line speed of the thin steel plate with a plate width of 300 mm was 80 m/min. However, no molten zinc leaked from the opening 4 at the bottom of the container, and stable plating operations could be maintained.
（比較例１）
第１図に示す空中ポット８において、容器底部の開口外
部周辺の雰囲気を露点−５０℃の２５％Ｈ２＋ ７５％
Ｎ２、シール板５と鋼板２との間隔を２．５ ｍ ｍ、
シール板５の先端における亜鉛浴６のヘッド高さを１０
０ｍｍ、溶融亜鉛浴温を４６５℃とした状態において、
還元性雰囲気中で焼鈍してから、４６５℃まで冷却した
板幅３００ｍｍの薄鋼板を５０ｍ／分のライン速度で通
板した。Ｎ２ガスワイパーによって溶融亜鉛の付着量を
５０ ｇ ／ ｍ ２に制御したところ、容器底部の開
口部４近傍の溶融亜鉛の酸化が生じず開口部４から溶融
亜鉛の漏出が生して、安定なめっき操業を持続すること
ができなかった。(Comparative Example 1) In the aerial pot 8 shown in Fig. 1, the atmosphere around the outside of the opening at the bottom of the container was 25% H2 + 75% with a dew point of -50°C.
N2, the distance between the seal plate 5 and the steel plate 2 is 2.5 mm,
The head height of the zinc bath 6 at the tip of the seal plate 5 is set to 10
0mm and the molten zinc bath temperature was 465°C,
A thin steel plate having a width of 300 mm, which had been annealed in a reducing atmosphere and then cooled to 465° C., was threaded at a line speed of 50 m/min. When the amount of molten zinc deposited was controlled to 50 g/m2 using an N2 gas wiper, oxidation of the molten zinc near the opening 4 at the bottom of the container did not occur, and molten zinc leaked from the opening 4, resulting in a stable condition. Plating operations could not be sustained.
（比較例２）
容器底部の開口外部周辺の雰囲気を、空電、シール板５
と鋼板２との隙間を０．７ ｍ ｍとする他は実施例１
と同様な操業条件にしたところ、容器底部の開口部４か
ら溶融亜鉛の漏出はなかったが、鋼板面の酸化が部分的
に発生すると共に、局部的な不めっきが発生し、安定な
めっき操業を持続することができなかった。(Comparative Example 2) The atmosphere around the outside of the opening at the bottom of the container was
Example 1 except that the gap between the steel plate 2 and the steel plate 2 was set to 0.7 mm.
Under the same operating conditions as above, there was no leakage of molten zinc from the opening 4 at the bottom of the container, but oxidation of the steel plate surface occurred partially and local unplating occurred, making stable plating operations difficult. could not be sustained.
なお以上の説明においては薄鋼板への溶融亜鉛めっきの
例に関してのみ述べたが、これは本発明を溶融Ａｆｆ及
び溶融へ２合金めっきなどの他の溶融めっきにも適用す
ること、また、ワイピングを行なったのちに鋼板及びめ
っき金属層を加熱して合金化することを妨げるものでは
ない。In the above explanation, only the example of hot-dip galvanizing on thin steel sheets has been described, but this also means that the present invention can be applied to other hot-dip galvanizing such as hot-dip Aff and hot-dip 2-alloy plating, and that wiping can also be applied to other hot-dip galvanizing. This does not preclude heating and alloying the steel plate and the plated metal layer after this process.
［発明の効果］
以上述べたように、本発明の溶融金属めっき鋼板の製造
方法によれば、表面欠陥の原因となりやすいジンクロー
ルなどの浴中機器を用いることな（、溶融亜鉛めっき鋼
板を長時間にわたって安定に製造することができるので
、産業上の利用分野めて大きい。[Effects of the Invention] As described above, according to the method for producing a hot-dip galvanized steel sheet of the present invention, it is possible to produce a hot-dip galvanized steel sheet for a long time without using bath equipment such as zinc roll, which is likely to cause surface defects. Since it can be produced stably over time, it has a wide range of industrial applications.
第１図は本発明を好運に実施できる装置の縦断面図、第
２図はシール板と鋼板との隙間の縦断面の拡大図であり
、第２図（ａ）は溶融亜鉛が漏出する場合、第２図（ｂ
）は溶融亜鉛が漏出しない場合を示し、第３図は従来例
の装置の縦断面図である。
１・・−デフレクタロール ２−鋼板
３−・・サポートロール ４・・−開口部５・・・シ
ール板 ６・−亜鉛浴７・・−ガスワイパー
８・・−空中ポット９−底部 ＩＯ・
・−ジンクロール１１−・・スナウトFig. 1 is a longitudinal cross-sectional view of an apparatus that can successfully carry out the present invention, Fig. 2 is an enlarged longitudinal cross-sectional view of the gap between the seal plate and the steel plate, and Fig. 2 (a) is a case in which molten zinc leaks. , Figure 2 (b
) shows the case where molten zinc does not leak out, and FIG. 3 is a longitudinal sectional view of the conventional apparatus. 1... - Deflector roll 2 - Steel plate 3 - Support roll 4... - Opening 5... Seal plate 6 - Zinc bath 7... - Gas wiper
8...-Aerial pot 9-Bottom IO・
・-Jinkroll 11-・・Snout
Claims (1)
ら被めっき鋼板を連続的に該浴中に侵入させた後、めっ
き金属層の付着した鋼板を該浴の上方に引き上げ、つい
で余剰のめっき金属を払拭して溶融金属めっき鋼板を製
造するにあたり、 前記容器の開口部に設けられるシール板の 開口の鋼板厚さ方向の寸法を被めっき鋼板厚さより大き
くすると共に、すくなくとも被 めっき鋼板の侵入する容器底部の開口部近傍の溶融金属
の表面張力を大きくする手段を講じて、該シール板と被
めっき鋼板の間隙から溶融金属の漏洩を防止しながらめ
っきを行うことを特徴とする溶融金属めっき鋼板の製造
方法。 ２ 前記溶融金属の表面張力を大きくする手段が、被め
っき鋼板の侵入する容器底部の開口部外部周辺の雰囲気
を溶融金属に対して酸化性とすることである請求項１記
載の溶融金属めっき鋼板の製造方法。 ３ 前記被めっき鋼板の侵入する容器底部の開口部外部
周辺の雰囲気が溶融金属に対して酸化性であり、かつ被
めっき鋼板に対しては非酸化性である請求項２記載の溶
融金属めっき鋼板の製造方法。 ４ 前記被めっき鋼板の侵入する容器底部の開口部外部
周辺の雰囲気が実質的に水素、窒素および水蒸気の混合
雰囲気である請求項２または３記載の溶融金属めっき鋼
板の製造方 法。[Claims] 1. After a steel plate to be plated is continuously introduced into the bath through an opening at the bottom of a container holding a hot-dip metal bath, the steel plate with the plated metal layer is placed above the bath. When producing a hot-dip metal plated steel plate by pulling up, then wiping off excess plated metal, the size of the opening of the seal plate provided at the opening of the container in the thickness direction of the steel plate is made larger than the thickness of the steel plate to be plated, and at least Plating is performed while preventing leakage of molten metal from the gap between the seal plate and the steel plate to be plated by taking measures to increase the surface tension of the molten metal near the opening at the bottom of the container into which the steel plate to be plated enters. A method for manufacturing a hot-dip metal-plated steel sheet. 2. The molten metal-plated steel sheet according to claim 1, wherein the means for increasing the surface tension of the molten metal is to make the atmosphere around the outside of the opening at the bottom of the container into which the steel sheet to be plated enters oxidizing to the molten metal. manufacturing method. 3. The hot dip metal plated steel sheet according to claim 2, wherein the atmosphere around the outside of the opening at the bottom of the container through which the steel sheet to be plated enters is oxidizing to the molten metal and non-oxidizing to the steel sheet to be plated. manufacturing method. 4. The method for manufacturing a hot-dip metal-plated steel sheet according to claim 2 or 3, wherein the atmosphere around the outside of the opening at the bottom of the container into which the steel sheet to be plated enters is substantially a mixed atmosphere of hydrogen, nitrogen, and water vapor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13968390A JP2613309B2 (en) | 1990-05-31 | 1990-05-31 | Manufacturing method of hot-dip coated steel sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13968390A JP2613309B2 (en) | 1990-05-31 | 1990-05-31 | Manufacturing method of hot-dip coated steel sheet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0436447A true JPH0436447A (en) | 1992-02-06 |
| JP2613309B2 JP2613309B2 (en) | 1997-05-28 |
Family
ID=15251000
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13968390A Expired - Lifetime JP2613309B2 (en) | 1990-05-31 | 1990-05-31 | Manufacturing method of hot-dip coated steel sheet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2613309B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015137423A (en) * | 2014-01-24 | 2015-07-30 | 日新製鋼株式会社 | APPARATUS AND METHOD FOR MANUFACTURING Al PLATED STEEL WIRE |
-
1990
- 1990-05-31 JP JP13968390A patent/JP2613309B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015137423A (en) * | 2014-01-24 | 2015-07-30 | 日新製鋼株式会社 | APPARATUS AND METHOD FOR MANUFACTURING Al PLATED STEEL WIRE |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2613309B2 (en) | 1997-05-28 |
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