JPS6352088B2 - - Google Patents
Info
- Publication number
- JPS6352088B2 JPS6352088B2 JP15846578A JP15846578A JPS6352088B2 JP S6352088 B2 JPS6352088 B2 JP S6352088B2 JP 15846578 A JP15846578 A JP 15846578A JP 15846578 A JP15846578 A JP 15846578A JP S6352088 B2 JPS6352088 B2 JP S6352088B2
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- galvanized steel
- steel sheet
- treatment
- continuous
- 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.)
- Expired
Links
- 238000011282 treatment Methods 0.000 claims description 40
- 238000010438 heat treatment Methods 0.000 claims description 38
- 229910001335 Galvanized steel Inorganic materials 0.000 claims description 28
- 239000008397 galvanized steel Substances 0.000 claims description 28
- 238000000034 method Methods 0.000 claims description 24
- 238000005275 alloying Methods 0.000 claims description 19
- 238000001816 cooling Methods 0.000 claims description 18
- 229910000831 Steel Inorganic materials 0.000 claims description 13
- 239000010959 steel Substances 0.000 claims description 13
- 238000007747 plating Methods 0.000 claims description 12
- 238000000137 annealing Methods 0.000 claims description 11
- 230000006698 induction Effects 0.000 claims description 10
- 238000005246 galvanizing Methods 0.000 claims description 4
- 239000010410 layer Substances 0.000 description 17
- 239000000463 material Substances 0.000 description 8
- 229910045601 alloy Inorganic materials 0.000 description 6
- 239000000956 alloy Substances 0.000 description 6
- 238000002791 soaking Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000001953 recrystallisation Methods 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 229910001327 Rimmed steel Inorganic materials 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Coating With Molten Metal (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Description
本発明は、連続溶融亜鉛メツキ鋼板の連続過時
効処理法に関するものである。
連続焼鈍材を素材とする溶融亜鉛メツキ鋼板
は、インライン焼鈍、アウトライン焼鈍を問わ
ず、バツチ型焼鈍材を素材としたものよりも硬質
となることが免れ得ない。これは、連続焼鈍過程
で加熱、再結晶焼鈍、冷却の短時間の熱サイクル
に付され、特に冷却速度が速いことにより、バツ
チ型焼鈍材（徐冷材）よりも、過飽和に固溶した
炭素、窒素を多く含むことに基因している。しか
し、連続焼鈍材を溶融浸漬メツキするアルミニウ
ムメツキ鋼板の製造法（センジミア法）は、その
大量生産性と品質管理面に多大の利点を有するが
ゆえに、硬質であることがさほど問題とならない
用途材として、非常な発展をみた。だが、近年複
雑なまたは高度な加工を要する用途に対しても、
亜鉛メツキ鋼板の優れた特性を生かした適用が望
まれるようになり、センジミア法による連続溶融
亜鉛メツキ鋼板に良好な加工性を付与する技術の
開発が強く要望されるようになつた。
この連続焼鈍材を溶融浸漬メツキする亜鉛メツ
キ鋼板（以后、これを単に、連続溶融亜鉛メツキ
鋼板と呼ぶことにする）を軟質化し、プレス成形
性を高めるには、基本的には前述の過飽和固溶炭
素を安定した炭化物として析出させ、固溶体硬化
を取り除くことである。
この連続溶融亜鉛メツキ鋼板を軟質化する方法
としては、例えば、特公昭47−33409号、特公昭
51−30017号、特公昭46−3642号、特開昭51−
149128号の各公報記載の方法が知られている。
特公昭47−33409号公報記載の方法は、連続焼
鈍炉に過時効処理炉を直結するものであり、再結
晶焼鈍温度から500℃以下にまで50℃／sec以上で
急冷し、300〜500℃に10秒以上保持する均熱過時
効処理するものである。しかし、この方法を連続
メツキラインに適用する場合には、メツキ浴の前
に過時効処理炉を設置することになるので過時効
処理が必須となり、過時効処理を必ずしも必要と
しない成品の生産構成比が高い場合には、この過
時効処理炉が無用化して操業性および生産性の向
上にとつては、必ずしも有益とはならない。
特公昭51−30017号公報および特公昭46−3642
号公報記載の方法は、いづれも連続溶融亜鉛メツ
キ鋼板に対しバツチ型焼鈍過時効を行なうもので
あり、前者では亜鉛メツキ層に２次合金層が全面
的に形成される340〜370℃で30〜120分の過時効
処理を行なうことを教え、後者は亜鉛メツキ層に
２次合金層が形成されない280〜300℃で15〜50分
の過時効処理を行なうことを教えている。しかし
いづれにしても、バツチ型焼鈍炉で過時効処理す
るので、せつかく連続焼鈍して短時間焼鈍を行な
つた利点が半減されてしまい、連続ラインの有利
性が損われることになる。
また、特開昭51−149128号公報には、連続溶融
亜鉛メツキ鋼板を350〜450℃で１〜５分の連続過
時効処理する方法が開示されている。しかしこの
方法においてはメツキ層における合金層の発達の
問題を亜鉛浴中のAl濃度により抑制することが
示されており、浴管理が重要な要件とされてい
る。すなわち、メツキ層の二次合金化を抑制する
ことを目的としており、このため例えば400℃附
近（実際は380℃以上）の温度では浴中のAl濃度
0.5〜1.0％まで増加させるとしている。だが、実
操業面では、合金化処理を行なう場合があり（例
えば塗装性の面では合金化処理を行なう方が有利
である）、この合金化処理のさいにはAl濃度を低
くするというように亜鉛メツキ鋼板の種類に応じ
て浴組成を通い分けることは実操業上非常に煩雑
化する。また、過時効処理の加熱炉としては燃焼
ガス雰囲気炉が開示されているが、かかる外熱式
では急速加熱に限界があり、過時効帯コイル長さ
が長いものとならざるを得ない。例えば、Al濃
度が0.5％以下の亜鉛メツキ浴を用いた場合に、
二次合金層の発達を抑えるには、過時効温度の上
限は約380℃であるから、この温度での保持時間
は５分程度要するが、この温度への加熱時間とそ
の保持時間を考えると、通板速度を100m／secと
すれば、過時効帯コイル長さは500m以上もの長
さを必要とすることになつてしまう。
本発明は、既述の如き公知方法の問題を有しな
い連続溶融亜鉛メツキ鋼板の連続過時効処理法を
提供するもので、
インライン焼鈍型の連続溶融亜鉛メツキ装置で
メツキされた亜鉛メツキ鋼板を、誘導加熱帯域と
調冷帯域とを含む熱処理炉に通板し、この熱処理
炉において、該メツキ鋼板を425〜460℃の温度に
加熱したあとこの温度に２〜４分間保持し、次い
で徐冷するヒートサイクルを付与することを特徴
とする、メツキ層の合金化処理を判う連続溶融亜
鉛メツキ鋼板の連続過時効処理法、および、
インライン焼鈍型の連続溶融亜鉛メツキ装置で
メツキされた亜鉛メツキ鋼板を、誘導加熱帯域と
調冷帯域を含む熱処理炉に連続的に通板し、この
熱処理炉において、該メツキ鋼板を340〜370℃の
温度に加熱し、この温度に16分以内保持するヒー
トサイクルを付与することを特徴とするメツキ層
の合金化処理を伴わない連続溶融亜鉛メツキ鋼板
の連続過時効処理法、を開発したものである。
以下、図面を参照しつつ本発明法を具体的に説
明する。
第１図は、連続溶融亜鉛メツキ鋼板の過時効処
理条件を示すもので、本発明で採用する条件範囲
を説明するためのものである。第１図において、
曲線Ａ−A′は亜鉛メツキ層の合金化が完了する
境界を示すもので、この曲線Ａ−A′より上の領
域では合金化が完了する。曲線Ｂ−B′は亜鉛メ
ツキ層の合金層においてΓ相が発達する境界を示
すもので、この曲線Ｂ−B′より上の領域ではΓ
相が発達する。したがつて曲線Ａ−A′と曲線Ｂ
−B′との間の領域では、合金層の表層はδ1相とな
り、Γ相は実質上発達しない。曲線Ｃ−C′は鋼板
の過時効処理をほぼ達成するに必要な下限を示
し、過時効処理後の鋼板の機械的性質を調べて判
定したものである。ただし、完全な過時効の効果
を期待しなくてもよい場合には、この曲線Ｃ−
C′より若干下方となつてもよい。本発明法は、後
述の熱処理炉を用いて、メツキ層の合金化処理を
行なう場合には曲線Ａ−A′と曲線Ｂ−B′との間
の温度範囲でかつこの温度域に２〜４分間の保持
範囲とする（第１図におけるＸ領域）のであり、
メツキ層の合金化処理を行なわない場合には、曲
線Ｃ−C′と曲線Ａ−A′との間または場合によつ
ては曲線Ｃ−C′より若干下方の領域であつて、か
つ保持時間が16分以内、好ましくは６分以上の領
域（第１図のＹ領域）とする熱管理を行なう。換
言すれば、後述の熱処理炉を用いて、合金化処理
を行なう亜鉛メツキ鋼板に対しては、処理温度
425〜460℃で２〜４分間の連続過時効処理条件と
し、非合金化亜鉛メツキ鋼板に対しては、処理温
度340〜370℃で16分以内の連続過時効処理条件と
するのである。
第２図は、本発明で用いる過時効処理炉の配置
系統図であり、上段は横型炉、下段は竪型炉を示
している。本発明の効果を調査する段階において
は縮少モデムの上段の横型炉を用いたが、熱効率
を優先させる場合には、下段のような竪型炉の採
用が有利である。熱処理炉の主要構成は、亜鉛メ
ツキ鋼板（４で示す）の流れの順に、誘導加熱帯
域１、調冷または均熱帯域２、および調冷帯域３
からなる。本発明の１つの特徴は、このような誘
導加熱帯域１をもつ熱処理炉により過時効処理を
連続的に行なうことにあり、所定の過時効温度ま
で急速加熱を行なうのである。鋼帯の加熱に通常
用いられる外部加熱方式では昇温速度に限界があ
り、本発明のヒートサイクルを有利に実施し難
い。この誘導加熱帯域１を通過することによつて
所定の温度にまで内部加熱式に急速加熱された亜
鉛メツキ鋼板は、次の調冷または均熱帯域２およ
び調冷帯域３において、合金化処理の有無に応じ
て所定の温度管理がなされる。例えば、合金化処
理の場合には、帯域２と３はいづれも徐々に冷却
が行なわれるような機能をもち、合金化処理を行
なわない場合には、帯域２は誘導加熱帯域１で
340〜370℃となつた鋼板温度を所定時間保持させ
る均熱機能を果たす。このように、調冷帯域を２
と３に分割したのは、この熱処理炉の適用を亜鉛
メツキ層の合金化の有無に対して即応できるよう
にするとともに、この亜鉛メツキ鋼板のほかに、
必要に応じて他の成品例えば連続焼鈍材自体や連
続焼鈍を経た溶融アルミニウムメツキ鋼板にも適
宜切替使用できるようにしたからである。なお、
第２図において、５は熱処理炉の前の付帯装置、
６は熱処理炉の後の付帯装置を示している。
第３図は、本発明法による連続溶融亜鉛メツキ
鋼板の過時効処理の代表的なヒートサイクルを示
すもので、サイクルX′は合金化処理を行なうヒ
ートサイクル、サイクルY′は合金化処理を行な
わないヒートサイクルであり、図中の数字は第２
図の熱処理炉の各帯域１，２，３に対応してい
る。サイクルX′においては、誘導加熱帯域１を
通過する間に約400℃程度まで急速加熱され、均
熱帯域２を通過する間に425〜460℃の温度に少な
くとも４分以内保持され、調冷帯域３に入ると、
放冷に近い冷却速度で調冷される。また、サイク
ルY′においては、誘導加熱帯域１を通過する間
に約300℃程度まで急速加熱され、均熱帯域２と
３で340〜370℃の温度に少なくとも16分以内（図
では約６分）保持されたあと放冷される。
以下に、このヒートサイクルを適用した実施例
について述べる。
90トン転炉で溶製した、Ｃ；0.06％、Mn；
0.28％、Si；tr、Ｐ；0.016％、Ｓ；0.016％、の
リムド鋼を通常の方法で冷間圧延して0.8mm厚に
仕上げたあと、センジミア型連続溶融亜鉛メツキ
装置（メツキ浴は0.26％のAlを含有）に、メツキ
目付量が40ｇ／m2（両面）となるように、通板し
た。この連続溶融亜鉛メツキ鋼板を第２図の上段
に示す縮少モデムの水平炉に通板し、第３図のヒ
ートサイクルX′とY′を適用した。その後は1.2％
のスキンパスを付与した。この各過時時効処理を
施した鋼板とこの過時効処理を施す前の各鋼板の
各種試験値を第１表に示した。
The present invention relates to a continuous over-aging treatment method for continuous hot-dip galvanized steel sheets. Hot-dip galvanized steel sheets made from continuous annealing materials are inevitably harder than those made from batch-annealed materials, regardless of whether they are in-line annealed or outline annealed. This material is subjected to a short thermal cycle of heating, recrystallization annealing, and cooling during the continuous annealing process, and because of its particularly fast cooling rate, it has a higher concentration of supersaturated solid solution carbon and nitrogen than batch annealed material (slow cooling material). This is due to the fact that it contains a large amount of However, the manufacturing method of aluminum-plated steel sheets (Sendzimir method), which involves hot-dip-plating continuously annealed materials, has great advantages in terms of mass productivity and quality control. As such, we have seen tremendous progress. However, in recent years, even for applications that require complex or advanced processing,
Applications that take advantage of the excellent properties of galvanized steel sheets have become desirable, and there has been a strong demand for the development of a technology that imparts good workability to continuous hot-dip galvanized steel sheets using the Sendzimir process. Basically, in order to soften the galvanized steel sheet (hereinafter simply referred to as continuous hot-dip galvanized steel sheet) obtained by hot-dip galvanizing this continuously annealed material and improve its press formability, the above-mentioned supersaturated solidification method is basically used. The purpose is to precipitate molten carbon as stable carbide and eliminate solid solution hardening. As a method for softening this continuous hot-dip galvanized steel sheet, for example, Japanese Patent Publication No. 47-33409,
No. 51-30017, Japanese Patent Publication No. 1973-3642, Japanese Patent Publication No. 1973-
The method described in each publication of No. 149128 is known. The method described in Japanese Patent Publication No. 47-33409 is a method in which an overaging furnace is directly connected to a continuous annealing furnace, and quenching is performed at a rate of 50°C/sec or more from the recrystallization annealing temperature to 500°C or less, and then the temperature is increased from 300 to 500°C. This is a soaking and over-aging treatment that is held for at least 10 seconds. However, when this method is applied to a continuous plating line, an overaging treatment furnace is installed before the plating bath, so overaging treatment is essential, and the production composition ratio of products that do not necessarily require overaging treatment is If this is high, this overaging treatment furnace becomes useless and is not necessarily beneficial for improving operability and productivity. Special Publication No. 51-30017 and Special Publication No. 46-3642
The methods described in the publication all involve batch-type overaging of continuous hot-dip galvanized steel sheets; in the former, a secondary alloy layer is formed entirely on the galvanized layer at 340 to 370°C for 30°C. The latter teaches to perform an over-aging treatment for ~120 minutes, and the latter teaches to perform an over-aging treatment for 15-50 minutes at 280-300° C. so that no secondary alloy layer is formed on the galvanized layer. However, in any case, since the overaging treatment is performed in a batch-type annealing furnace, the advantage of continuous annealing and short-time annealing is halved, and the advantage of a continuous line is lost. Further, Japanese Patent Application Laid-open No. 149128/1983 discloses a method of continuously overaging a hot-dip galvanized steel sheet at 350 to 450° C. for 1 to 5 minutes. However, in this method, it has been shown that the problem of alloy layer development in the plating layer can be suppressed by the Al concentration in the zinc bath, and bath management is considered an important requirement. In other words, the purpose is to suppress secondary alloying of the plating layer, and for this reason, for example, at temperatures around 400°C (actually over 380°C), the Al concentration in the bath decreases.
The company plans to increase it to 0.5-1.0%. However, in actual operation, alloying treatment is sometimes performed (for example, alloying treatment is more advantageous in terms of paintability), and during this alloying treatment, it is necessary to lower the Al concentration. Differentiating the bath composition depending on the type of galvanized steel sheet is extremely complicated in actual operation. Further, although a combustion gas atmosphere furnace has been disclosed as a heating furnace for overaging treatment, such an external heating type has a limit in rapid heating, and the length of the overaging zone coil must be long. For example, when using a galvanized bath with an Al concentration of 0.5% or less,
In order to suppress the development of the secondary alloy layer, the upper limit of the overaging temperature is approximately 380°C, so the holding time at this temperature is approximately 5 minutes, but considering the heating time to this temperature and the holding time. If the threading speed is 100 m/sec, the length of the over-aged zone coil will be 500 m or more. The present invention provides a continuous over-aging treatment method for continuous hot-dip galvanized steel sheets that does not have the problems of known methods as described above. The plated steel sheet is passed through a heat treatment furnace including an induction heating zone and a cooling zone, and in this heat treatment furnace, the plated steel sheet is heated to a temperature of 425 to 460°C, held at this temperature for 2 to 4 minutes, and then slowly cooled. Continuous over-aging treatment method for continuous hot-dip galvanized steel sheet, characterized by applying a heat cycle, which determines the alloying treatment of the plating layer, and galvanized steel sheet plated with an in-line annealing type continuous hot-dip galvanizing device is continuously passed through a heat treatment furnace including an induction heating zone and a cooling zone, and in this heat treatment furnace, the plated steel sheet is heated to a temperature of 340 to 370°C and maintained at this temperature for no more than 16 minutes. We have developed a continuous over-aging treatment method for continuous hot-dip galvanized steel sheets that does not involve alloying treatment of the plating layer, which is characterized by imparting the following properties: Hereinafter, the method of the present invention will be specifically explained with reference to the drawings. FIG. 1 shows overaging treatment conditions for a continuous hot-dip galvanized steel sheet, and is intended to explain the range of conditions employed in the present invention. In Figure 1,
The curve A-A' indicates the boundary at which alloying of the galvanized layer is completed, and alloying is completed in the region above this curve A-A'. The curve B-B' indicates the boundary where the Γ phase develops in the alloy layer of the galvanized layer, and in the area above this curve B-B', the Γ
phase develops. Therefore, curve A-A' and curve B
In the region between -B', the surface layer of the alloy layer becomes a δ 1 phase, and the Γ phase does not substantially develop. The curve C-C' indicates the lower limit required to substantially achieve the over-aging treatment of the steel sheet, and was determined by examining the mechanical properties of the steel sheet after the over-aging treatment. However, if you do not expect a complete overaging effect, use the curve C-
It may be slightly lower than C'. In the method of the present invention, when alloying the plating layer using the heat treatment furnace described below, the temperature range is between the curve A-A' and the curve B-B', and within this temperature range 2 to 4 The holding range is (X area in Figure 1).
If the plating layer is not alloyed, the area is between curve C-C' and curve A-A', or in some cases slightly below curve C-C', and the retention time is Heat management is performed so that the heating time is within 16 minutes, preferably 6 minutes or more (region Y in FIG. 1). In other words, for galvanized steel sheets that undergo alloying treatment using the heat treatment furnace described below, the treatment temperature
Continuous overaging treatment conditions are set at 425 to 460°C for 2 to 4 minutes, and for non-alloyed galvanized steel sheets, continuous overaging treatment is performed at a treatment temperature of 340 to 370°C for 16 minutes or less. FIG. 2 is a layout diagram of the overaging furnace used in the present invention, with the upper stage showing a horizontal furnace and the lower stage showing a vertical furnace. At the stage of investigating the effects of the present invention, a horizontal furnace on the upper stage of the reduced modem was used, but if priority is given to thermal efficiency, it is advantageous to employ a vertical furnace like the one on the lower stage. The main components of the heat treatment furnace are, in the order of flow of galvanized steel sheets (indicated by 4), an induction heating zone 1, a cooling or soaking zone 2, and a cooling zone 3.
Consisting of One feature of the present invention is that the overaging treatment is continuously performed using a heat treatment furnace having such an induction heating zone 1, and rapid heating is performed to a predetermined overaging temperature. The external heating method normally used for heating steel strips has a limit on the rate of temperature increase, making it difficult to carry out the heat cycle of the present invention advantageously. The galvanized steel sheet, which has been rapidly internally heated to a predetermined temperature by passing through the induction heating zone 1, undergoes alloying treatment in the next cooling or soaking zone 2 and cooling zone 3. Predetermined temperature management is performed depending on the presence or absence. For example, in the case of alloying, zones 2 and 3 both function as gradual cooling; in the absence of alloying, zone 2 is induction heating zone 1.
It performs a heat soaking function that maintains the steel plate temperature at 340-370℃ for a predetermined period of time. In this way, the cooling zone is divided into 2
The reason why this heat treatment furnace is divided into 3 parts is to enable immediate response to the application of this heat treatment furnace to whether or not the galvanized layer is alloyed, and in addition to this galvanized steel sheet,
This is because it can be used for other products, such as the continuously annealed material itself or a continuously annealed molten aluminum plated steel plate, if necessary. In addition,
In Fig. 2, 5 is ancillary equipment in front of the heat treatment furnace;
6 indicates ancillary equipment after the heat treatment furnace. Figure 3 shows a typical heat cycle for overaging treatment of continuous hot-dip galvanized steel sheets according to the method of the present invention, where cycle X' is a heat cycle in which alloying treatment is performed, and cycle Y' is a heat cycle in which alloying treatment is performed. The number in the figure is the second heat cycle.
This corresponds to each zone 1, 2, and 3 of the heat treatment furnace shown in the figure. In cycle When entering 3,
Cooling is controlled at a cooling rate close to that of natural cooling. In cycle Y', the temperature is rapidly heated to about 300℃ while passing through induction heating zone 1, and the temperature reaches 340 to 370℃ in soaking zones 2 and 3 within at least 16 minutes (about 6 minutes in the figure). ) and then left to cool. Examples to which this heat cycle is applied will be described below. Smelted in a 90-ton converter, C; 0.06%, Mn;
Rimmed steel of 0.28%, Si; % of Al), so that the plating weight was 40 g/m 2 (both sides). This continuous hot-dip galvanized steel sheet was passed through a horizontal furnace of a reduced modem shown in the upper row of Fig. 2, and heat cycles X' and Y' shown in Fig. 3 were applied. After that, 1.2%
granted a skin pass. Table 1 shows various test values of the steel plates subjected to each of the over-aging treatments and the steel plates before being subjected to the over-aging treatments.
【表】
第１表の結果から明らかなように、合金化処理
のヒートサイクルX′も、非合金化処理のヒート
サイクルY′も共に、全伸びE1が大巾に上昇して
著しく軟質化しており、コニカルカツプテスト値
（CCV）も良好なプレス成形性を示している。[Table] As is clear from the results in Table 1, in both the heat cycle X' for alloying treatment and the heat cycle Y' for non-alloying treatment, the total elongation E1 increased significantly and became significantly softer. The conical cup test value (CCV) also shows good press formability.
第１図は連続溶融亜鉛メツキ鋼板の過時効処理
条件を示す時間と温度との関係図、第２図は本発
明法に従う熱処理炉の配置系統図、第３図は本発
明法に従う代表的なヒートサイクル図である。
１……誘導加熱帯域、２……均熱または調冷帯
域、３……調冷帯域。
Fig. 1 is a diagram showing the relationship between time and temperature showing the overaging treatment conditions for continuous hot-dip galvanized steel sheets, Fig. 2 is a layout diagram of a heat treatment furnace according to the method of the present invention, and Fig. 3 is a typical diagram according to the method of the present invention. It is a heat cycle diagram. 1...Induction heating zone, 2...Soaking or cooling zone, 3...Cooling zone.
Claims (1)
でメツキされた亜鉛メツキ鋼板を、誘導加熱帯域
と調冷帯域とを含む熱処理炉に連続的に通板し、
この熱処理炉において、該メツキ鋼板を425〜460
℃の温度に加熱したあとこの温度に２〜４分間保
持し、次いで徐冷するヒートサイクルを付与する
ことを特徴とする、メツキ層の合金化処理を伴う
連続溶融亜鉛メツキ鋼板の連続過時効処理法。 ２ インライン焼鈍型の連続溶融亜鉛メツキ装置
でメツキされた亜鉛メツキ鋼板を、誘導加熱帯域
と調冷帯域を含む熱処理炉に連続的に通板し、こ
の熱処理炉において、該メツキ鋼板を340〜370℃
の温度に加熱し、この温度に16分以内保持するヒ
ートサイクルを付与することを特徴とするメツキ
層の合金化処理を伴わない連続溶融亜鉛メツキ鋼
板の連続過時効処理法。[Claims] 1. A galvanized steel sheet plated with an in-line annealing continuous hot-dip galvanizing device is continuously passed through a heat treatment furnace including an induction heating zone and a cooling zone,
In this heat treatment furnace, the plated steel plate is
Continuous over-aging treatment of a continuous hot-dip galvanized steel sheet accompanied by alloying treatment of the plating layer, characterized by applying a heat cycle of heating to a temperature of °C, holding this temperature for 2 to 4 minutes, and then slowly cooling. Law. 2. A galvanized steel sheet plated with an in-line annealing type continuous hot-dip galvanizing device is continuously passed through a heat treatment furnace including an induction heating zone and a cooling zone, and in this heat treatment furnace, the galvanized steel sheet is heated to a temperature of 340 to 370 ℃
A continuous over-aging treatment method for continuous hot-dip galvanized steel sheets that does not involve alloying treatment of the plating layer, characterized by applying a heat cycle in which the steel sheets are heated to a temperature of , and maintained at this temperature for 16 minutes or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15846578A JPS5585624A (en) | 1978-12-25 | 1978-12-25 | Continuous over-aging method for continuously hot-zinc dipped steel sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15846578A JPS5585624A (en) | 1978-12-25 | 1978-12-25 | Continuous over-aging method for continuously hot-zinc dipped steel sheet |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5585624A JPS5585624A (en) | 1980-06-27 |
| JPS6352088B2 true JPS6352088B2 (en) | 1988-10-18 |
Family
ID=15672326
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15846578A Granted JPS5585624A (en) | 1978-12-25 | 1978-12-25 | Continuous over-aging method for continuously hot-zinc dipped steel sheet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5585624A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6258497B1 (en) * | 1992-07-29 | 2001-07-10 | International Business Machines Corporation | Precise endpoint detection for etching processes |
-
1978
- 1978-12-25 JP JP15846578A patent/JPS5585624A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5585624A (en) | 1980-06-27 |
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