JPH0565534A - Method of decarburizing and annealing for cold rolled steel sheet - Google Patents
Method of decarburizing and annealing for cold rolled steel sheetInfo
- Publication number
- JPH0565534A JPH0565534A JP22568191A JP22568191A JPH0565534A JP H0565534 A JPH0565534 A JP H0565534A JP 22568191 A JP22568191 A JP 22568191A JP 22568191 A JP22568191 A JP 22568191A JP H0565534 A JPH0565534 A JP H0565534A
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- annealing
- treatment
- steel sheet
- rolled steel
- decarburizing
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は冷延鋼板の脱炭焼なまし
方法に係わり、深絞り性、耐二次加工脆性および非時効
性に優れた冷延鋼板とする脱炭焼なまし方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for decarburizing and annealing a cold rolled steel sheet, and more particularly to a method for decarburizing and annealing a cold rolled steel sheet which is excellent in deep drawability, resistance to secondary work embrittlement and non-aging.
【０００２】[0002]
【従来の技術】一般にプレス加工に供される冷延鋼板に
は、ｒ値および伸び値が高いことが要求される。このよ
うな冷延鋼板は素材として低炭素アルミキルド鋼または
リムド鋼を用い、これらの鋼を熱間圧延および冷間圧延
した後、オープコイル焼なまし処理して機械的性質を改
善し、且つこの焼なまし処理中に脱炭処理して鋼中の炭
素（Ｃ）を減少させ深絞り性を高めることによって製造
されている。2. Description of the Related Art Generally, cold rolled steel sheets used for press working are required to have high r value and elongation value. Such a cold-rolled steel sheet uses low carbon aluminum killed steel or rimmed steel as a material, and after hot rolling and cold rolling of these steels, an open coil annealing treatment is performed to improve mechanical properties and It is manufactured by decarburizing during the annealing process to reduce carbon (C) in the steel and to enhance deep drawability.
【０００３】脱炭処理は焼なまし処理中に水蒸気を焼な
まし炉内に吹き込むことにより行われているが、この脱
炭処理が不十分で鋼中に 11ppm以上のＣが残存すると、
その冷延鋼板は時効劣化を生じて伸び値が著しく低下す
る。The decarburizing treatment is carried out by blowing steam into the annealing furnace during the annealing treatment. If the decarburizing treatment is insufficient and 11 ppm or more of C remains in the steel,
The cold-rolled steel sheet is deteriorated by aging and its elongation value is significantly reduced.
【０００４】図３はＣ含有量の異なる冷延鋼板を 100℃
の温度で30分間時効処理したときの伸び（ＥＬ）値の低
下を調べたものであり、図中、○印は時効処理する前に
測定した伸び値、●印は時効処理後に測定した伸び値で
ある。図３から明らかなように鋼中のＣ量が 10ppm以下
の場合は時効処理しても伸び値の低下が小さいが、11pp
m 以上では時効処理すると伸び値の低下が大きい。FIG. 3 shows cold rolled steel sheets having different C contents at 100 ° C.
The decrease in the elongation (EL) value after aging treatment for 30 minutes at the temperature is examined. In the figure, ○ indicates the elongation value measured before aging treatment, ● indicates the elongation value measured after aging treatment. Is. As is clear from Fig. 3, when the C content in the steel is 10 ppm or less, the decrease in the elongation value is small even after the aging treatment.
If it is more than m, there is a large decrease in elongation value after aging treatment.
【０００５】このように時効劣化により伸び値が大きく
低下すると、その冷延鋼板は成形性能が損なわれるばか
りか、降伏点伸び（ＹＰＥ）が現れ、これが 0.5％以上
になるとストレッチャストレインが発生する。このた
め、従来は焼なまし処理中は徹底的に脱炭処理して鋼中
のＣ量をできるだけ低くするようにしているが、本発明
者らの知見では必要以上の脱炭は耐二次加工脆性を低下
させる。When the elongation value greatly decreases due to aging deterioration, not only the forming performance of the cold-rolled steel sheet is impaired, but also the yield point elongation (YPE) appears, and when it exceeds 0.5%, stretcher strain occurs. For this reason, conventionally, during the annealing treatment, the decarburization treatment is thoroughly performed so as to reduce the amount of C in the steel as much as possible. Reduces work brittleness.
【０００６】冷延鋼板は自動車や家電製品等の外装材と
して賞用されているが、最近ではこれらの製品のデザイ
ンが多様化および複雑化して形成条件が厳しくなり、一
部の用途で二次加工脆性による割れの問題が生じてい
る。本発明者らがこの原因を調べたところ、鋼中Ｃ量が
４ppm 以下の冷延鋼板に集中的に割れが発生しているこ
とがわかった。これは脱炭処理で鋼中のＣ量を極端に低
くすると結晶粒界の強度が低下するからであると考えら
れる。Cold-rolled steel sheets are widely used as exterior materials for automobiles and home electric appliances, but recently, the design conditions of these products have become diversified and complicated, and the forming conditions have become strict. There is a problem of cracking due to work brittleness. When the present inventors investigated the cause of this, it was found that the cold-rolled steel sheet having a C content in the steel of 4 ppm or less intensively cracked. It is considered that this is because if the amount of C in the steel is extremely reduced by the decarburizing treatment, the strength of the crystal grain boundary is reduced.
【０００７】[0007]
【発明が解決しようとする課題】ホーロー製品のケトル
や自動車のフェンダー等のような難加工製品に使用され
る冷延鋼板には、深絞り性は勿論のこと、この深絞り性
を維持するための非時効性や耐二次加工脆性などの特性
が必要である。しかしながら、冷延鋼板に良好な深絞り
性を付与するために焼なまし処理中に脱炭処理して鋼中
のＣ量を４ppm 以下にまで低減すると耐二次加工脆性が
損なわれ、脱炭が不十分で鋼中に 11ppm以上のＣが残存
すると非時効性が損なわれる。The cold-rolled steel sheet used in difficult-to-process products such as kettles for enamel products and fenders for automobiles has not only deep drawability but also for maintaining this deep drawability. Properties such as non-aging resistance and secondary work embrittlement resistance are required. However, if decarburization is performed during the annealing process to reduce the C content in the steel to 4 ppm or less in order to impart good deep drawability to the cold-rolled steel sheet, the secondary work brittleness resistance is impaired, and decarburization is reduced. Is insufficient, and if 11 ppm or more of C remains in the steel, the non-aging property is impaired.
【０００８】従って、非時効性および耐二次加工脆性を
損なうことなく、深絞り性を確保するには鋼中のＣ量が
５〜10ppm の範囲内となるように脱炭処理するのがよい
と考えられるが、実操業で鋼中のＣ量をこの範囲内に正
確に調整することは容易ではない。Therefore, in order to secure the deep drawability without impairing the non-aging property and the secondary work embrittlement resistance, it is preferable to perform the decarburizing treatment so that the C content in the steel is within the range of 5 to 10 ppm. However, it is not easy to accurately adjust the C content in steel within this range in actual operation.
【０００９】本発明の課題は、確実に鋼中のＣ量を５〜
10ppm の範囲内にコントロールすることができて、深絞
り性、耐二次加工脆性および非時効性に優れた冷延鋼板
を得ることができる脱炭焼まなし方法を提供することに
ある。The object of the present invention is to ensure that the C content in steel is 5 to 5.
It is an object of the present invention to provide a decarburizing annealing method capable of obtaining a cold rolled steel sheet which can be controlled within the range of 10 ppm and is excellent in deep drawability, resistance to secondary work embrittlement and non-aging.
【００１０】[0010]
【課題を解決するための手段】本発明者らは、焼なまし
処理中に水蒸気を雰囲気ガス中に吹き込んで鋼中のＣを
脱炭する処理を、焼なまし炉から排出されるガス中のＣ
Ｏ（一酸化炭素）濃度が一定の値に至った時点で終了す
れば、確実に鋼中のＣ量を５〜10ppm とすることができ
ることを見出した。DISCLOSURE OF THE INVENTION The present inventors have conducted a process for decarburizing C in steel by blowing steam into the atmosphere gas during the annealing process in the gas discharged from the annealing furnace. C
It has been found that the C content in the steel can be reliably set to 5 to 10 ppm if the processing is finished when the O (carbon monoxide) concentration reaches a certain value.
【００１１】上記知見に基づく本発明は「Ｃ：0.10wt％
以下、Ｍｎ：0.1 〜0.8 wt％、Ｐ：0.03wt％以下、残部
がＦｅおよび不可避不純物からなる冷延鋼板をオープン
コイル焼なまし処理する際に、その焼なまし処理中に焼
なまし炉内に水蒸気を吹き込んで脱炭処理する過程で焼
なまし炉から排出されるガス中のＣＯ濃度が 0.20 〜0.
35 vol％に至った時点で水蒸気の吹き込みを停止して脱
炭処理を終了することを特徴とする冷延鋼板の脱炭焼な
まし方法」を要旨とする。The present invention based on the above knowledge shows that "C: 0.10 wt%
Hereinafter, when an open coil annealing treatment is performed on a cold-rolled steel sheet having Mn: 0.1 to 0.8 wt%, P: 0.03 wt% or less, and the balance being Fe and inevitable impurities, an annealing furnace is used during the annealing treatment. The CO concentration in the gas discharged from the annealing furnace during the process of decarburizing by blowing steam into the inside is 0.20 to 0.
The outline is a method for decarburizing and annealing a cold-rolled steel sheet, which is characterized in that the blowing of steam is stopped at the time of reaching 35 vol% and the decarburizing treatment is terminated.
【００１２】[0012]
【作用】以下、添付図面を参照して本発明を更に詳細に
説明する。The present invention will be described in more detail with reference to the accompanying drawings.
【００１３】図１は冷延鋼板のオープンコイル焼なまし
処理におけるヒートサイクルを示したものである。FIG. 1 shows a heat cycle in an open coil annealing treatment of a cold rolled steel sheet.
【００１４】焼なまし処理は、焼まなし炉にオープンコ
イルを装入し、10〜20 vol％水素（Ｈ2)＋窒素（Ｎ2)ガ
スの雰囲気中で、図１に示すように再結晶温度以上 Ar3
変態点以下の温度域に昇熱し、その温度域で均熱保持し
た後、消火して炉から取り出すことにより行われる。こ
の焼なまし処理において、オープンコイルを Ar3変態点
より高い温度域に加熱しない理由は、 Ar3変態点を超し
てオーステナイト組織となると、鋼のＣ吸蔵能力が増し
て脱炭が困難となり、鋼中には多量のＣが残存するから
である。In the annealing treatment, an open coil is charged in an unannealed furnace, and re-oxidation is performed in an atmosphere of 10 to 20 vol% hydrogen (H 2 ) + nitrogen (N 2 ) gas as shown in FIG. Above crystal temperature Ar 3
It is carried out by raising the temperature to a temperature range below the transformation point, maintaining the temperature in the temperature range so uniform, extinguishing the fire and taking it out of the furnace. In this annealing process, why not heated open coil temperature range higher than the Ar 3 transformation point, when the austenite structure staggering Ar 3 transformation point, C storage capacity of the steel decarburization becomes difficult increased This is because a large amount of C remains in the steel.
【００１５】脱炭処理は、この焼なまし処理中の昇熱過
程或いは均熱過程の 500℃以上 Ar3変態点以下を出発点
として焼まなし炉に水蒸気を吹き込むことで行われる。
水蒸気の吹き込み量は、ガス雰囲気のＨ2 分圧、Ｈ2 Ｏ
分圧および温度などから調整される。焼なまし炉に水蒸
気を吹き込むと、下記式の反応が起こることにより鋼中
の炭素が脱炭される。The decarburization treatment is carried out by blowing steam into the unannealing furnace starting from a temperature of 500 ° C. or higher and Ar 3 transformation point or lower during the heating process or soaking process during the annealing process.
The amount of water vapor blown is H 2 partial pressure of gas atmosphere, H 2 O
It is adjusted from the partial pressure and temperature. When steam is blown into the annealing furnace, the carbon in the steel is decarburized by the reaction of the following formula.
【００１６】 Ｃ ＋Ｈ2 Ｏ→ＣＯ＋Ｈ2 （ Ｃ ：鋼中の炭素） 本発明の方法では、前記の焼なまし炉に水蒸気を吹き込
んで行う脱炭処理を、焼なまし炉から排出されるガス中
のＣＯ濃度が0.20〜0.35 vol％に至った時点で水蒸気の
吹き込みを停止する。その理由は排ガス中のＣＯ濃度が
0.20〜0.35 vol％の範囲外である時点で水蒸気の吹き込
みを停止して脱炭処理を終了すると、鋼中のＣ量が５〜
10ppm にならず、二次加工脆性による割れまたはストレ
ッチャストレインが発生しやすくなるからである。C + H 2 O → CO + H 2 (C: carbon in steel) In the method of the present invention, the decarburization treatment performed by blowing steam into the annealing furnace is a gas discharged from the annealing furnace. When the CO concentration in the inside reaches 0.20 to 0.35 vol%, the blowing of steam is stopped. The reason is that the CO concentration in the exhaust gas is
If the blowing of steam is stopped and the decarburization treatment is finished at a point outside the range of 0.20 to 0.35 vol%, the C content in the steel will be 5 to 5.
This is because the content does not reach 10 ppm, and cracking or stretcher strain due to brittleness in secondary processing easily occurs.
【００１７】図２は脱炭処理終了時の排ガス中のＣＯ濃
度と鋼中のＣ量との関係と、脆性割れおよびストレッチ
ャストレインの有無とを調べたものである。脆性割れお
よびストレッチャストレインの有無は後述する実施例と
同じ試験をして調べた。図中、○印は脆性割れおよびス
トレッチャストレインがともに無し、△印は脆性割れは
無いがストレッチャストレインが発生、×印はストレッ
チャストレインは無いが脆性割れが発生したことを表
す。FIG. 2 shows the relationship between the CO concentration in the exhaust gas at the end of the decarburization treatment and the C content in the steel, and the presence or absence of brittle cracks and stretcher strains. The presence or absence of brittle cracking and stretcher strain was examined by the same test as in the examples described later. In the figure, ◯ indicates that neither brittle cracking nor stretcher strain was present, Δ indicates that there was no brittle cracking but stretcher strain occurred, and X indicates that there was no stretcher strain but brittle cracking occurred.
【００１８】図２から明らかなように、排ガス中のＣＯ
濃度が 0.20vol％より低い時点で脱炭処理を終了した場
合は、鋼中のＣ量が５ppm より低く、脆性割れが発生し
ており、排ガス中のＣＯ濃度が0.35 vol％を超えた時点
で脱炭処理を終了した場合は、鋼中のＣ量が10ppm を超
えており、ストレッチャストレインが発生している。As is clear from FIG. 2, CO in the exhaust gas
If the decarburization treatment is completed when the concentration is lower than 0.20 vol%, the C content in the steel is lower than 5 ppm, brittle cracking has occurred, and the CO concentration in the exhaust gas exceeds 0.35 vol%. When the decarburization treatment was completed, the amount of C in the steel exceeded 10 ppm, and stretcher strain had occurred.
【００１９】これに対して、排ガス中のＣＯ濃度が0.20
〜0.35 vol％の時点で脱炭処理を終了した場合には、鋼
中のＣ量が５〜10ppm であり、脆性割れおよびストレッ
チャストレインが発生していない。また、鋼中のＣ量が
５〜10ppm であれば、前述の図３から明らかなように時
効効処理後の伸び値の低下が小さく、深絞り性にも優れ
ている。On the other hand, the CO concentration in the exhaust gas is 0.20
When the decarburizing treatment is completed at the point of ~ 0.35 vol%, the amount of C in the steel is 5-10 ppm, and brittle cracking and stretcher strain are not generated. When the amount of C in the steel is 5 to 10 ppm, the decrease in elongation value after aging treatment is small and the deep drawability is excellent, as is clear from FIG.
【００２０】本発明において焼なまし処理中に脱炭処理
する対象材は、Ｃ：0.10wt％以下、Ｍｎ：0.1 〜0.8 wt
％、Ｐ：0.03wt％以下、残部がＦｅおよび不可避不純物
からなる冷延鋼板である。このように組成を限定したの
は下記の理由からである。In the present invention, the material to be decarburized during the annealing treatment is C: 0.10 wt% or less, Mn: 0.1 to 0.8 wt.
%, P: 0.03 wt% or less, the balance being Fe and inevitable impurities. The reason for limiting the composition in this way is as follows.
【００２１】Ｃ：Ｃはオープンコイル焼なまし処理で脱
炭処理して５〜10ppm に低減する。このため、出発材料
のＣ含有量は少ない方がよい。Ｃ含有量が多くなると脱
炭処理時間が長くなって焼なまし作業の効率が低下する
ようになることから、0.10wt％を上限とした。C: C is decarburized by open coil annealing to reduce it to 5 to 10 ppm. Therefore, it is preferable that the C content of the starting material is small. When the C content is high, the decarburization treatment time becomes long and the efficiency of the annealing work decreases, so 0.10 wt% was set as the upper limit.
【００２２】Ｍｎ：Ｍｎの含有量が 0.1wt％より低いと
Ｍｎ／Ｓの値が低くなって赤熱脆化が発生しやすくな
り、0.8 wt％を超えると固溶強化によって製品の伸び値
やｒ値が低下して深絞り性が低下する。従って、Mnの含
有量は 0.1〜0.8 wt％とした。Mn: When the content of Mn is less than 0.1 wt%, the value of Mn / S becomes low and red hot embrittlement easily occurs, and when it exceeds 0.8 wt%, the elongation value and r of the product are increased due to solid solution strengthening. The value decreases and the deep drawability decreases. Therefore, the Mn content is set to 0.1 to 0.8 wt%.
【００２３】Ｐ：Ｐの含有量が0.03wt％を超えると粒界
に偏析し、粒界強度が低下して耐二次加工脆性が損なわ
れる。また、固溶強化によって製品の伸び値やｒ値が低
下して深絞り性が低下する。従って、Ｐは0.03wt％以下
でできるだけ少ない方がよい。P: If the P content exceeds 0.03 wt%, segregation occurs at the grain boundaries, the grain boundary strength decreases, and the secondary work embrittlement resistance is impaired. Further, the solid solution strengthening lowers the elongation value and r value of the product, and thus the deep drawability is lowered. Therefore, P is preferably 0.03 wt% or less and as small as possible.
【００２４】[0024]
【実施例】表１に示す組成の冷延鋼板（板厚８mm) を 1
8vol％Ｈ2 −Ｎ2 ガスの雰囲気中で、710 ℃の温度に加
熱してオープンコイル焼なまし処理するとともにその処
理中に水蒸気を吹き込んで脱炭処理した。EXAMPLE A cold rolled steel sheet (sheet thickness 8 mm) having the composition shown in Table 1
In an atmosphere of 8 vol% H 2 —N 2 gas, heating was performed at a temperature of 710 ° C. to perform an open coil annealing treatment, and steam was blown into the treatment for decarburization treatment.
【００２５】水蒸気は 620℃の時点から焼まなし炉に吹
き込み、焼まなし炉から排出されるガス中のＣＯ濃度が
0.12〜0.55vol ％に至った時点で吹き込みを停止し、脱
炭処理を終えた。The steam is blown into the furnace without 620 ° C., and the CO concentration in the gas discharged from the furnace is
When it reached 0.12 to 0.55 vol%, the blowing was stopped and the decarburization treatment was completed.
【００２６】表１に脱炭終了時の排ガス中のＣＯ濃度と
脱炭焼なまし後に測定した鋼中のＣ量を併記する。ま
た、表２に脱炭焼なまし後の冷延鋼板の機械的性質、脆
性割れの有無およびストレッチャストレインの有無を調
べた結果を示す。Table 1 shows the CO concentration in the exhaust gas at the end of decarburization and the C content in the steel measured after decarburization annealing. In addition, Table 2 shows the results of examining the mechanical properties of the cold-rolled steel sheet after decarburization annealing, the presence or absence of brittle cracking, and the presence or absence of stretcher strain.
【００２７】機械的性質は脱炭焼なまし後の冷延鋼板お
よびこれNI更に100℃で30分間保持の時効処理を施した
後の冷延鋼板からＪＩＳ５号の試験片を圧延方向から切
り出し、引張り試験して求めた。二次加工脆性を表す脆
性割れは、絞り比1.8 に加工し、−50℃の温度で落重に
より破壊後、破面を観察した。ストレッチャストレイン
は板幅方向に３％の引張り歪みを付与した後、油砥石で
表面研磨し、その表面を目視観察して有無を調べた。Mechanical properties of the cold-rolled steel sheet after decarburizing and annealing and the cold-rolled steel sheet after NI had been subjected to an aging treatment of holding at 100 ° C. for 30 minutes were cut out from the rolling direction of JIS No. 5 test pieces and stretched. Tested and found. The brittle crack, which represents the secondary work brittleness, was processed to a drawing ratio of 1.8, fractured by falling weight at a temperature of -50 ° C, and then the fracture surface was observed. The stretcher strain was subjected to a tensile strain of 3% in the plate width direction, then surface-polished with an oil grindstone, and the surface was visually observed to check the presence or absence.
【００２８】[0028]
【表１】 [Table 1]
【００２９】[0029]
【表２】 [Table 2]
【００３０】表１および表２に示すとおり、排ガス中の
ＣＯ濃度が本発明で規定する0.20〜0.35 vol％の時点で
脱炭処理を終了したものは製品の鋼中Ｃ量が５〜10ppm
であり、それらの製品は時効処理後の伸び値はほとんど
低下しておらず、ストレッチャストレインおよび脆性割
れが認められない。これに対して、排ガス中のＣＯ濃度
が0.20 vol％より低い時点で終了した比較例は製品の鋼
中Ｃ量が４ppm 以下で、脆性割れが発生しており、0.35
vol％より高い時点で脱炭処理を終了した比較例は鋼中
Ｃ量が11ppm 以上で、時効処理後の伸び値の低下が大き
く、 0.5％以上のＹＰＥが現れてストレッチャストレイ
ンが発生している。As shown in Tables 1 and 2, the decarburization treatment completed when the CO concentration in the exhaust gas was 0.20 to 0.35 vol% specified in the present invention, the C content in the steel of the product was 5 to 10 ppm.
In these products, the elongation value after aging treatment is hardly reduced, and stretcher strain and brittle cracking are not observed. On the other hand, in the comparative example that was completed when the CO concentration in the exhaust gas was lower than 0.20 vol%, the C content in the steel of the product was 4 ppm or less, and brittle cracking occurred.
In the comparative example in which the decarburization treatment was completed at a point higher than vol%, the C content in the steel was 11 ppm or more, the elongation value after aging treatment was large, and YPE of 0.5% or more appeared and stretcher strain occurred. ..
【００３１】[0031]
【発明の効果】実施例にも示したように、本発明の方法
で冷延鋼板の脱炭焼なましをすれば、深絞り性、耐二次
加工脆性および非時効性に優れたものとなる。As shown in the examples, decarburization annealing of a cold rolled steel sheet by the method of the present invention provides excellent deep drawability, secondary work embrittlement resistance and non-aging resistance. ..
【図１】冷延鋼板のオープンコイル焼なまし処理におけ
るヒートサイクルを示す図である。FIG. 1 is a diagram showing a heat cycle in an open coil annealing treatment of a cold rolled steel sheet.
【図２】脱炭処理終了時の排ガス中のＣＯ濃度と鋼中の
Ｃ量との関係と、脆性割れおよびストレッチャストレイ
ンの有無の調査結果を示すグラフである。FIG. 2 is a graph showing the relationship between the CO concentration in exhaust gas and the amount of C in steel at the end of decarburization treatment, and the results of investigations on the presence or absence of brittle cracks and stretcher strains.
【図３】Ｃ含有量の異なる冷延鋼板を 100℃の温度で30
分間時効処理したときの伸び（ＥＬ）値の低下を示すグ
ラフである。[Fig. 3] Cold rolled steel sheets with different C contents at a temperature of 100 ° C
It is a graph which shows the fall of the elongation (EL) value at the time of aging treatment for minutes.
Claims (1)
％、Ｐ：0.03wt％以下、残部がＦｅおよび不可避不純物
からなる冷延鋼板をオープンコイル焼なまし処理する際
に、その焼なまし処理中に焼なまし炉内に水蒸気を吹き
込んで脱炭処理する過程で焼なまし炉から排出されるガ
ス中のＣＯ濃度が0.20〜0.35 vol％に至った時点で水蒸
気の吹き込みを停止して脱炭処理を終了することを特徴
とする冷延鋼板の脱炭焼なまし方法。1. C: 0.10 wt% or less, Mn: 0.1 to 0.8 wt.
%, P: 0.03 wt% or less, when cold-rolled steel sheet with the balance being Fe and inevitable impurities is subjected to open coil annealing treatment, steam is blown into the annealing furnace during the annealing treatment to decarburize. In the process of treatment, when the CO concentration in the gas discharged from the annealing furnace reaches 0.20 to 0.35 vol%, the blowing of steam is stopped and the decarburization treatment is terminated. Decarburization annealing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22568191A JPH0565534A (en) | 1991-09-05 | 1991-09-05 | Method of decarburizing and annealing for cold rolled steel sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22568191A JPH0565534A (en) | 1991-09-05 | 1991-09-05 | Method of decarburizing and annealing for cold rolled steel sheet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0565534A true JPH0565534A (en) | 1993-03-19 |
Family
ID=16833123
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22568191A Pending JPH0565534A (en) | 1991-09-05 | 1991-09-05 | Method of decarburizing and annealing for cold rolled steel sheet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0565534A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5619371A (en) * | 1979-07-24 | 1981-02-24 | Aisin Seiki Co Ltd | Electromagnetic motor |
-
1991
- 1991-09-05 JP JP22568191A patent/JPH0565534A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5619371A (en) * | 1979-07-24 | 1981-02-24 | Aisin Seiki Co Ltd | Electromagnetic motor |
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