JPS61195965A - Production of alloyed and galvanized steel sheet - Google Patents

Abstract

PURPOSE:To produce an alloyed and galvanized steel sheet by subjecting one or both surfaces of a cold rolled steel sheet to galvanizing by vacuum deposition then heating the same in a batch annealing furnace in a non-oxidizing or weakly reducing atmosphere thereby alloying the galvanizing layer and the steel sheet. CONSTITUTION:The steel sheet 1 is introduced through a gas reduction pretreatment furnace 2, a pressurizing chamber 3 and a sealing roll chamber 4 into a vacuum deposition plating chamber 5 where the plating layer of Zn deposited by evaporation is formed on the bottom surface of the steel sheet 1 in a molten Zn bath 6. The steel sheet is introduced into the 2nd vacuum deposition plating chamber 5' by deflector rolls 7, 7' and Zn is deposited by evaporation on the opposite surface of the sheet as well in the case of forming the plating layers deposited by evaporation on both surfaces of the steel sheet. The steel sheet is then taken out through the sealing roll chamber 4' and the pressurizing chamber 3' and is coiled. The coil is put into the batch annealing furnace where the coil is heated to 250-350 deg.C and is held at said temp. for 1-15hr in the non-oxidizing or weakly reducing atmosphere. The alloy layer of Fe and Zn is formed at the boundary face between the galvanizing layer and the steel sheet, by which the alloyed and galvanized steel sheet is produced.

Description

【発明の詳細な説明】 １皇公１ 本発明は真空蒸着亜鉛めっき鋼帯を所定条件下で加熱す
ることにより１合金化させた合金化亜鉛めっき鋼板を製
造する方法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an alloyed galvanized steel sheet in which a vacuum-deposited galvanized steel strip is heated under predetermined conditions to form a single alloy.

びそ　− 合金化亜鉛めっき鋼板は合金化しない通常の亜鉛めっき
鋼板に比べ。Biso - Alloyed galvanized steel sheet is compared to normal non-alloyed galvanized steel sheet.

イ）スポット溶接における連続操業性がよい。b) Good continuous operation in spot welding.

口）電着塗装における塗装密着性が良好であり、したが
って電着塗装後の耐食性も良好である、という利点から
、広く一般に使用されている。ところで従来合金化亜鉛
めっき鋼板の製造方法は、次のような方法がある。(1) It is widely used because of its advantages in that it has good paint adhesion during electrodeposition and therefore has good corrosion resistance after electrodeposition. By the way, conventional methods for manufacturing alloyed galvanized steel sheets include the following methods.

ａ）溶融亜鉛めっきの直後にめっきされた亜鉛が凝固し
ない内に加熱処理して合金化する方法。a) A method of heat-treating and alloying the plated zinc immediately after hot-dip galvanizing before it solidifies.

ｂ）電気亜鉛めっき鋼板を再加熱処理して合金化する方
法。b) A method of reheating and alloying an electrogalvanized steel sheet.

ところがこれらの亜鉛めっき合金化方法には次のような
問題がある。まずａ）の方法は溶融めっきを利用する方
法であるので片面あたり３０ｇ／層２以下の均一な薄め
つきを得ることが困難でありまた片面めっきを得ること
はきわめて困難であった。However, these galvanizing alloying methods have the following problems. First, since method a) utilizes hot-dip plating, it is difficult to obtain a uniform thin plating of 30 g/layer 2 or less per side, and it is extremely difficult to obtain plating on one side.

又、　ｂ）の方法は、電気亜鉛めっきにより亜鉛を被覆
するため通常は亜鉛の付着量が４０ｇ／■２以下に制限
される。付着量が４０ｇ／■２を越えると電気亜鉛めっ
きで製造することはコスト上好ましくないからである。Furthermore, in method b), since the zinc is coated by electrogalvanizing, the amount of zinc deposited is usually limited to 40 g/2 or less. This is because if the amount of adhesion exceeds 40 g/2, manufacturing by electrogalvanizing is not preferable in terms of cost.

本発明は従来の製造方法にみられたと記問題点を解決す
るものであり、合金化亜鉛めっき被覆を形成する際、亜
鉛の付着量に制限が無く、かつ、必要に応じて鋼帯の片
面ないし両面のいずれにも合金化亜鉛めっきを形成でき
、しかもめっき被覆の厚さが均一な高品質の合金化亜鉛
めっきを得ることのできる製造方法を提供するものであ
る。The present invention solves the problems described in conventional manufacturing methods, and when forming an alloyed galvanized coating, there is no limit to the amount of zinc deposited, and if necessary, one side of the steel strip can be coated with zinc. The purpose of the present invention is to provide a manufacturing method capable of forming an alloyed zinc plating on either or both sides, and obtaining a high quality alloyed zinc plating with a uniform thickness of the plating coating.

本発明は電気亜鉛めっき鋼板より安価であり、かつ付着
量の制限がない蒸着亜鉛めっき鋼板に着目し真空蒸着亜
鉛めっきを利用し該めっき後所定条件下で加熱処理する
ことにより、上記従来技術の問題点を解消したものであ
る。The present invention focuses on vapor-deposited galvanized steel sheets, which are cheaper than electro-galvanized steel sheets and has no restrictions on the amount of coating, and utilizes vacuum vapor-deposited galvanizing, and heat-treats the sheets under predetermined conditions after the plating. This solves the problem.

１１立亘羞 本発明によれば、冷延鋼帯の片面または両面に真空蒸着
亜鉛めっきを施した後、バッチ焼鈍炉内で非酸化性また
は弱還元性雰囲気で２５０〜３５０℃まで加熱昇温し、
その温度で１〜１５時間保持して亜鉛被覆と鋼帯とを合
金化させることを特徴とする合金化亜鉛めっき鋼板の製
造方法が提供される。According to the present invention, after vacuum-deposited galvanizing is applied to one or both sides of a cold-rolled steel strip, the temperature is heated to 250 to 350°C in a non-oxidizing or weakly reducing atmosphere in a batch annealing furnace. death,
A method for manufacturing an alloyed galvanized steel sheet is provided, which comprises holding the temperature at that temperature for 1 to 15 hours to alloy the zinc coating and the steel strip.

ヱ１ｂ先へｍ示 本発明の方法を冷延鋼帯に真空蒸着亜鉛めっきを施す工
程と、めっき後に鋼帯をコイル状とし、これをバッチ焼
鈍炉中で合金化のための加熱を行なう工程とに分けて説
明する。(1b) The method of the present invention includes a step of vacuum-deposited galvanizing a cold-rolled steel strip, and a step of forming the steel strip into a coil shape after the plating and heating it for alloying in a batch annealing furnace. I will explain it separately.

まず、真空蒸着亜鉛めっき工程について説明する。First, the vacuum evaporation galvanizing process will be explained.

連続式真空蒸着めっき装置にはいくつかの様式が提案さ
れており、その−例を１図に示す０図示するものはガス
還元前処理炉２、還元ガスあるいは空気の流入を防止す
るための賦圧室３．３”、一連の段階的に排気する個別
に真空排気手段を備えた隔室に納められた多数のシール
ロールからなる第１および第２のシールロール室４．４
”、鋼帯の片方の面に真空めっきするための第１真空め
っき室５、鋼帯の他方の面に真空蒸着めっきするための
第１真空蒸着めっき室に連通ずる第２真空蒸着めっき室
　５°から構成されている。尚、該真空蒸着めっき室５
．５”にはそれぞれ　亜鉛浴６．６°とデフレクタロー
ル７．７”が配設されている。Several types of continuous vacuum evaporation plating equipment have been proposed, an example of which is shown in Figure 1. The one shown is a gas reduction pre-treatment furnace 2, with equipment to prevent the inflow of reducing gas or air. a pressure chamber 3.3'', a first and a second sealing roll chamber 4.4 consisting of a number of sealing rolls housed in a series of stepwise evacuating compartments equipped with individual evacuation means;
”, a first vacuum plating chamber 5 for vacuum plating one side of the steel strip, and a second vacuum plating chamber 5 communicating with the first vacuum plating chamber for vacuum plating the other side of the steel strip. The vacuum deposition plating chamber 5
．． 5" are each equipped with a 6.6° zinc bath and a 7.7" deflector roll.

上記装置構成において、冷間圧延されたままの鋼帯ｌは
前処理炉２に連続的に導入され、焼鈍と同時にガス還元
による前処理を施された後、賦圧室３、段階的に排気さ
れる第１シールロール室４を経由して、第１真空蒸着め
っき室５に導入される。亜鉛浴６には図示されない供給
源から亜鉛が連続的に供給されて適当な手段（電気抵抗
加熱手段、電子ビーム加熱手段等）によって加熱、蒸発
され、鋼帯１の下方の面に蒸着めっきが施される。つい
で、鋼帯ｌは回廊部でデフレクタロール７．７°によっ
て、その上面と下面を逆転されて、第２真空蒸着めっき
室５°に導かれ、前述と同様に、鋼帯１のもう一つの面
に亜鉛浴６°からの蒸気によって蒸着めっきされる。そ
の後、鋼帯１は第２シールロール室４”、賦圧室３°を
経て真空蒸着装置系外に導出される。なおシールロール
室４，４°は段階的に減圧しながら真空蒸着めっき室へ
鋼帯を導入、導出するためのものであり、例えば　特願
昭５９−１９２５７４のものと同様である。シールロー
ル室は４．４°は図示されない排気管および多数の真空
ポンプにより排気され、段階的に減圧され、真空蒸着め
っき室５，５°を所定の真空に保持する。In the above apparatus configuration, the cold-rolled steel strip l is continuously introduced into the pretreatment furnace 2, and is subjected to pretreatment by gas reduction at the same time as annealing. It is introduced into the first vacuum evaporation plating chamber 5 via the first seal roll chamber 4 where it is heated. Zinc is continuously supplied to the zinc bath 6 from a supply source (not shown), heated and evaporated by suitable means (electrical resistance heating means, electron beam heating means, etc.), and deposited plating is formed on the lower surface of the steel strip 1. administered. Next, the steel strip 1 is turned around with its top and bottom surfaces reversed by a deflector roll 7.7 degrees in the corridor section, and guided into the second vacuum deposition plating chamber 5 degrees, where another layer of the steel strip 1 is turned in the same manner as described above. The surface is plated by vapor deposition from a 6° zinc bath. Thereafter, the steel strip 1 is led out of the vacuum evaporation system through the second seal roll chamber 4'' and the pressure chamber 3°. For example, it is similar to that in Japanese Patent Application No. 59-192574.The seal roll chamber is evacuated at 4.4° by an exhaust pipe and a number of vacuum pumps (not shown). The pressure is reduced stepwise to maintain the vacuum deposition plating chamber 5.5° at a predetermined vacuum.

次に合金化のための加熱工程について説明する。Next, a heating process for alloying will be explained.

合金化のための加熱はコイル状鋼帯を非酸化性または弱
還元性の雰囲気のバッチ焼鈍炉に投入して実施する。加
熱温度と保持時間の関係は付着量によっても異なるが、
通常保持時間が１時間より短いとコイル状鋼帯が昇温す
るのに必要な昇温時間が保持時間に対して短すぎ熱処理
条件を一定に保って操業することが困難になる。また、
１５時間より長いと、非能率となり実際の操業上適当で
ない、一方加熱温度が２５０℃より低いと合金化がめっ
きの表層まで進行しきらず、焼きむらが生じる。また加
熱温度が３５０℃より高いと、合金化が過度に進行し加
工の際にパウダリングと呼ばれるめっき部の損傷が生じ
る。付着量１０〜１００ｘｌ濡２の亜鉛めっきを施した
場合の好ましい加熱温度と保持時間の関係を第２図に示
す０図中のａ、ｂで囲まれる斜線部分の領域が好ましい
加熱処理条件の範囲である０次に、加熱により合金化処
理する時の雰囲気は非酸化性または弱還元性にする必要
がある。雰囲気が酸化性であると亜鉛めっき層の表面あ
るいは非めっきである鋼板表面が酸化するからである。Heating for alloying is carried out by placing the coiled steel strip in a batch annealing furnace in a non-oxidizing or weakly reducing atmosphere. The relationship between heating temperature and holding time varies depending on the amount of adhesion, but
Normally, if the holding time is shorter than 1 hour, the heating time required to raise the temperature of the coiled steel strip is too short compared to the holding time, making it difficult to operate while keeping the heat treatment conditions constant. Also,
If it is longer than 15 hours, it becomes inefficient and is not suitable for actual operation. On the other hand, if the heating temperature is lower than 250° C., alloying does not proceed to the surface layer of the plating, resulting in uneven baking. Furthermore, if the heating temperature is higher than 350° C., alloying progresses excessively and damage to the plated portion called powdering occurs during processing. Figure 2 shows the relationship between the preferred heating temperature and holding time when zinc plating is applied with a coating weight of 10 to 100xl. The shaded area surrounded by a and b in Figure 0 is the range of preferred heat treatment conditions. Next, the atmosphere during alloying treatment by heating must be non-oxidizing or weakly reducing. This is because if the atmosphere is oxidizing, the surface of the galvanized layer or the surface of the non-plated steel sheet will be oxidized.

−び 第１図に示す連続式真空蒸着亜鉛めっき装置を用いて冷
間圧延ままの鋼帯に真空蒸着亜鉛めっきを施した。操業
条件は次の通りである。- Vacuum evaporation galvanization was applied to a cold-rolled steel strip using a continuous vacuum evaporation galvanizing apparatus shown in FIG. The operating conditions are as follows.

鋼帯：　０．６ｓ■厚さ×３００■■暢の低炭素鋼通板
速度：１５■ｌ■ｉｎ 蒸着室圧カニ　Ｑ、０１ｔｏｒｒ 蒸発方法：抵抗加熱方式 ％式％ 片面めっきまたは両面めっき 尚、片面めっきを施す場合には、第１真空蒸着めっき室
または第２真空蒸着めっき室のいずれか一方だけで真空
蒸着亜鉛めっきすればよい。Steel strip: 0.6s Thickness x 300mm Low carbon steel Threading speed: 15lcm Deposition chamber pressure Q, 01torr Evaporation method: Resistance heating method % Single-sided or double-sided plating When single-sided plating is performed, the vacuum evaporation zinc plating may be performed only in either the first vacuum evaporation plating chamber or the second vacuum evaporation plating chamber.

これらの真空蒸着亜鉛めっき鋼板をオープルコイルに巻
き替えた後、バッチ焼鈍炉中で加熱し合金化処理し、合
金化亜鉛めっき鋼板を製造した。These vacuum-deposited galvanized steel sheets were re-wound into open coils, and then heated and alloyed in a batch annealing furnace to produce alloyed galvanized steel sheets.

合金化処理条件は次の通りである。The alloying treatment conditions are as follows.

炉内雰囲気：　ＨＮＸ（Ｈ２３％、Ｈ２９７％）ＤＰ−
２５℃ 加熱温度＝２５０〜３５０℃ 保持条件：１〜１５時間 付着量、加熱温度、保持時間の組み合せと製造された鋼
板の表面外観、加工性（耐パウダリング性）を調べた結
果を第１表に示す、加工性は２膳−半径にθ０°曲げた
後内側のクラック発生状況で評価した。Furnace atmosphere: HNX (H23%, H297%) DP-
25℃ Heating temperature = 250 to 350℃ Holding conditions: 1 to 15 hours The results of investigating the combination of coating weight, heating temperature, and holding time, and the surface appearance and workability (powdering resistance) of the manufactured steel sheet were As shown in the table, the workability was evaluated based on the occurrence of cracks on the inner side after bending to a radius of θ0°.

次に比較のため加熱温度ないし保持時間を夫々第１表に
示す条件に設定し、その他は実施例と同様にして亜鉛め
っきの合金化処理を行なった。この結果を第１表に併せ
て示す。Next, for comparison, the heating temperature and holding time were set to the conditions shown in Table 1, and the other conditions were the same as in the examples to perform alloying treatment for zinc plating. The results are also shown in Table 1.

第１表 表中：付着量は鋼帯の両面または片面の付着量を示し。Table 1 In the table: The amount of adhesion indicates the amount of adhesion on both sides or one side of the steel strip.

例えば１０／１０は両面１０９／ｒｒｔの付着。For example, 10/10 has 109/rrt adhesion on both sides.

１０１０は片面１０９／ｍ”の付着である。1010 is an adhesion of 109/m'' on one side.

ｍと級釆 本発明は真空蒸着亜鉛めっきを利用するので、付着量の
制限なく、かつ鋼板の両方および片面の区別なく合金化
亜鉛めっきを施すことができる。Since the present invention utilizes vacuum-deposited galvanizing, alloyed galvanizing can be applied to both sides and one side of the steel sheet without any restrictions on the amount of coating.

更に、鋼板表面の合金化亜鉛めっき被覆は表面の外観が
良好であり、加工性もよく、高品位の合金化亜鉛めっき
鋼板を得ることができる。Furthermore, the alloyed galvanized coating on the surface of the steel sheet has a good surface appearance and good workability, and it is possible to obtain a high-grade alloyed galvanized steel sheet.

４１皿五亘１違１」 第１図は本発明の実施に用いる連続式真空蒸着めっき装
置の概略図、第２図は本発明の製造方法における加熱温
度と保持時間の好適な範囲を示すグラフである。Figure 1 is a schematic diagram of a continuous vacuum evaporation plating apparatus used to carry out the present invention, and Figure 2 is a graph showing the preferred ranges of heating temperature and holding time in the manufacturing method of the present invention. It is.

図面中、 １−鋼帯 ２−ガス還元前処理炉 ３．３’：賦圧室 ４．４’：シールロール室。In the drawing, 1-Steel strip 2-Gas reduction pretreatment furnace 3.3': Pressure chamber 4.4': Seal roll chamber.

５．５’：真空蒸着めっき室 ８．６　°：亜鉛浴 ７．７’：デフレクタロール5.5’: Vacuum deposition plating chamber 8.6 °: Zinc bath 7.7’: Deflector roll

Claims (1)

【特許請求の範囲】[Claims] 冷延鋼帯の片面または両面に真空蒸着亜鉛めっきを施し
た後、バッチ焼鈍炉内で非酸化性または弱還元性雰囲気
で２５０〜３５０℃まで加熱昇温し、その温度で１〜１
５時間保持して亜鉛被覆と鋼帯とを合金化させることを
特徴とする合金化亜鉛めっき鋼板の製造方法。After vacuum-deposited galvanizing is applied to one or both sides of a cold-rolled steel strip, the temperature is raised to 250-350°C in a non-oxidizing or weakly reducing atmosphere in a batch annealing furnace, and at that temperature 1-1
A method for producing an alloyed galvanized steel sheet, which comprises holding the zinc coating for 5 hours to alloy the zinc coating and the steel strip.