JPH0394020A - Production of cold rolled steel sheet for deep drawing excellent in resistance to secondary working brittleness - Google Patents
Production of cold rolled steel sheet for deep drawing excellent in resistance to secondary working brittlenessInfo
- Publication number
- JPH0394020A JPH0394020A JP1230873A JP23087389A JPH0394020A JP H0394020 A JPH0394020 A JP H0394020A JP 1230873 A JP1230873 A JP 1230873A JP 23087389 A JP23087389 A JP 23087389A JP H0394020 A JPH0394020 A JP H0394020A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- cold
- range
- amount
- resistance
- 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
- 239000010960 cold rolled steel Substances 0.000 title claims abstract description 13
- 238000004519 manufacturing process Methods 0.000 title claims description 12
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 31
- 239000010959 steel Substances 0.000 claims abstract description 31
- 238000000137 annealing Methods 0.000 claims abstract description 28
- 238000000034 method Methods 0.000 claims abstract description 14
- 238000001953 recrystallisation Methods 0.000 claims abstract description 8
- 238000005096 rolling process Methods 0.000 claims abstract description 8
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 5
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 4
- 239000012535 impurity Substances 0.000 claims abstract description 3
- 238000005097 cold rolling Methods 0.000 abstract description 8
- 229910052799 carbon Inorganic materials 0.000 abstract description 5
- 238000005098 hot rolling Methods 0.000 abstract description 5
- 239000000203 mixture Substances 0.000 abstract description 5
- 238000005255 carburizing Methods 0.000 description 14
- 230000000694 effects Effects 0.000 description 9
- 239000007789 gas Substances 0.000 description 9
- 238000012545 processing Methods 0.000 description 8
- 239000006104 solid solution Substances 0.000 description 7
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 229920006395 saturated elastomer Polymers 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005204 segregation Methods 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 239000002023 wood Substances 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000003048 aphrodisiac agent Substances 0.000 description 1
- 230000002509 aphrodisiac effect Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000005324 grain boundary diffusion Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000001568 sexual effect Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は連続焼鈍による耐２次加工脆性に優れた深絞り
用冷延鋼板の製造方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a cold-rolled steel sheet for deep drawing which has excellent resistance to secondary work brittleness due to continuous annealing.
（従来の技術）
近年、自動車部材や電気機器外板に使用される冷延鋼板
には、高いプレス戊形性が要求されている。(Prior Art) In recent years, cold-rolled steel sheets used for automobile parts and outer panels of electrical equipment are required to have high press formability.
このような要求を満たす冷延鋼板の製造方法としては、
極低炭素鋼にＴｊ．．Ｎｂなとの炭窒化物形戒元素を単
独又は複合添加して鋼中のＣ．Ｎを固定することにより
、深絞り性に有利な（１１１）面方位集合組織を発達さ
せる方法が提案されている。The manufacturing method for cold-rolled steel sheets that meets these requirements is as follows:
Tj. for ultra-low carbon steel. ．． Carbonitride type elements such as Nb are added singly or in combination to increase C. A method has been proposed in which a (111) plane orientation texture, which is advantageous for deep drawability, is developed by fixing N.
（発明が解決しようとする課題）
しかし、一方では、Ｔ１、Ｎｂなどの炭窒化物形成元素
により鋼中のＣ．Ｎを充分固定した極低炭素鋼では、プ
レス成形後の２次加工において脆性破断による割れが発
生するという問題がある。これは、鋼中の固溶Ｃが固定
され、フェライ１へ粒界へのＣの偏析がなくなって粒界
が脆化するためである。(Problems to be Solved by the Invention) However, on the other hand, carbonitride-forming elements such as T1 and Nb cause C. Ultra-low carbon steel in which N is sufficiently fixed has a problem in that cracks occur due to brittle fracture during secondary processing after press forming. This is because the solid solution C in the steel is fixed, and the segregation of C to the grain boundaries in the ferrite 1 disappears, causing the grain boundaries to become brittle.
更に、Ｐ添加鋼では、粒界にＰが偏析し、粒界の脆化を
助長するという問題がある。Furthermore, P-added steel has the problem that P segregates at grain boundaries, promoting embrittlement of the grain boundaries.
したがって、従来は、耐２次加工脆性の改善のために、
予め鋼中のＣ．Ｎが残存するようにＴｉやＮｂの添加量
を制御して溶製することが試みられていた。しかし、こ
の方法では、例え固溶Ｃ、Ｎが残存する成分鋼が溶製で
きたとしても、この固溶Ｃ．Ｎは本質的に鋼のｒ値や延
性を劣化させるものであるので、プレス戒形性の大幅な
低下を来たさざるを得なかった。すなわち、木質的にプ
レス成形性と耐２次加工脆性は両立し得ないものであっ
た。また、一方、このような微量ｃ．Ｎを残存させるこ
とは、製鋼技術上或り立つものでなかった。Therefore, conventionally, in order to improve secondary work brittleness,
C. in steel in advance. Attempts have been made to control the amounts of Ti and Nb added so that N remains. However, with this method, even if a steel with residual solid solute C and N can be produced, the solid solute C. Since N essentially deteriorates the r value and ductility of steel, it has inevitably caused a significant decrease in press formability. In other words, in terms of wood quality, press formability and secondary processing brittleness cannot be compatible. Moreover, on the other hand, such a trace amount of c. It has not been possible to allow N to remain in steel manufacturing technology.
この点、従来より、以下のような提案がなされているが
、プレス或形性と耐２次加工脆性を共に優れたものとす
ることは困ガ１である。In this regard, the following proposals have been made in the past, but it is difficult to achieve both excellent press formability and secondary processing brittleness resistance.
例えば、深絞り用鋼板の耐２次加工割れ性を改善する目
的で、Ｔｊ．Ｎｂを添加して鋼中のＣを固定し、冷間圧
延後オープンコイル焼鈍時に浸炭を行い、鋼板表面に浸
炭層を形成する方法（特開昭６３−３８５５６号）が提
案されている。しかし、この方法の場合、長時間に及ぶ
バッチ焼鈍の際に浸炭を実施するため、鋼板の表層部に
のみ高濃度の浸炭層（平均Ｃ量：０．０２〜０．１０％
）が形威され、また表層部と中心部でフェライ１一粒度
に差が生じる等、板厚方向に成分、組織が異かる鋼板と
なる問題があり、更に、こうしたバッチ焼鈍タイプでは
、当然乍ら生産性が低いと具に、板長及び板幅方向の材
質が不均一になり易い不利を生じる。For example, Tj. A method has been proposed (Japanese Unexamined Patent Publication No. 38556/1983) in which Nb is added to fix C in steel, and carburization is performed during open coil annealing after cold rolling to form a carburized layer on the surface of the steel sheet. However, in this method, since carburization is carried out during batch annealing over a long period of time, a highly concentrated carburized layer (average C content: 0.02 to 0.10%) is formed only on the surface layer of the steel sheet.
), and there is also a difference in the grain size of Ferrite 1 between the surface layer and the center, resulting in a steel sheet with different composition and structure in the thickness direction. If the productivity is low, the material tends to be non-uniform in the plate length and width directions.
また、同様に、Ｔｉ．Ｎｂを添加して深絞り用鋼ー３一
板を製造する方法として，冷間圧延後に再結晶焼鈍を行
った後、更に浸炭処理を施す方法（特開平１−９６３３
０号）もあるが、主に多量の炭化物、窒化物の析出によ
る強度の向−Ｌを狙ったものであって、耐２次加工脆性
に対する配慮がなく、また焼鈍後にバッチにて長時間浸
炭処理を行うため、浸炭量が過剰且つ不均一となり易く
、しかも生産性が低く、工程も煩雑になるという欠点が
ある。Similarly, Ti. As a method of manufacturing a deep drawing steel-3 sheet by adding Nb, a method of performing recrystallization annealing after cold rolling and then further carburizing treatment (Japanese Patent Application Laid-open No. 1-9633
There is also No. 0), but it is mainly aimed at increasing the strength by precipitating a large amount of carbides and nitrides, and does not take into consideration secondary processing brittleness, and does not require long-term carburizing in batches after annealing. Since the treatment is carried out, the amount of carburization tends to be excessive and non-uniform, and the productivity is low and the process is complicated.
本発明は、上記従来技術の技術の問題点を解決するため
になされたものであって、極低炭素鋼を用いて、プレス
成形性を損なうことなく、耐２次加工脆性に優れた深絞
り用冷延鋼板を生産性よく製造する方法を提供すること
を目的とするものである。The present invention has been made in order to solve the problems of the above-mentioned conventional technology, and uses ultra-low carbon steel to achieve deep drawing with excellent resistance to secondary work brittleness without impairing press formability. The object of the present invention is to provide a method for manufacturing cold-rolled steel sheets with high productivity.
（課題を解決するための手段）
力いる目的を達或するため、本発明者らは、従来の極低
炭素鋼においてプレス成形性が劣化する原因について検
討した。(Means for Solving the Problems) In order to achieve the objective, the present inventors investigated the causes of deterioration of press formability in conventional ultra-low carbon steels.
その結果、固溶Ｃ．Ｎがプレス或形性を低下させる原因
は、圧延集合組織の形或段階及び再結晶ｌ一
集合組織の形或段階で局所的なすへり系、転位の再配列
に影響を及ぼし、深絞り性に好ましい（１１１．）集合
組織の発達をｌ！Ｉｔ害するためであることが判明した
。As a result, solid solution C. The reason why N reduces press formability is that it affects the local shear system and rearrangement of dislocations at certain stages of rolling texture and recrystallization texture, and it affects deep drawability. Favorable (111.) Texture development l! It turned out that it was meant to harm people.
そこで、本発明者らは、このような原因を解消し、且つ
耐２次加工脆性を優れたものとし得る方策について鋭意
研究を重ねた結果、極低炭素鋼において特定の或分調整
を行うと共に圧延条件を規定することによって、再結晶
集合組織が決定される焼鈍時の再結晶完了時までは固溶
Ｃ．Ｎを零の状態にしておき、その後浸炭雰囲気ガス中
で連続焼鈍を行うことにより、最終製品段階で粒界に数
ｐｐｍ程度のＣを存在させ、粒界を強化することにより
、ＩＩｆ＆化を貼止する方法を見い出し、ここに本発明
をなしたものである。Therefore, the inventors of the present invention have conducted extensive research on measures that can eliminate such causes and improve secondary work brittleness resistance, and as a result, they have made certain adjustments to ultra-low carbon steel and By specifying the rolling conditions, solid solution C.I.C. By keeping N in a state of zero and then performing continuous annealing in a carburizing atmosphere gas, several ppm of C is present in the grain boundaries at the final product stage, strengthening the grain boundaries and making IIf&C paste. We have found a method to stop this, and hereby we have devised the present invention.
すなわち、本発明は、Ｃ：Ｑ．Ｑ０７％以下、Ｍｎ：０
．０５−０．５０％、Ｐ：Ｏｌ．２％以下、Ｓ：０．０
１５％以下、ｓｏ１．Ａｌ：０．００５〜０．０５％、
Ｎ：０．００６％以下を含有し、更にＴｉ及びＮｂの単
独又は複合添加で、下式（１）に従う有効Ｔｌ量（Ｔ］
＊と表す）及びＮｂ量とＣ量との関係が下式（２）
Ｔｉ＊＝ｔｏｔａｌＴｉ − （（４８／３２） Ｘ
Ｓ ＋ （４８／１４） Ｘ Ｎ）…（１）
１≦（Ｔｉ＊／４８＋ Ｎｂ／９３）／ （Ｃ／１２）
≦４．５…・（２）を満足する範囲で含有し、必要に応
じて更にＢ：０．０ ０ ０ １〜０．０ ０ ３ ０
％を含有し、残部がＦｅ及び不可避的不純物よりなる鋼
を、１０００〜１２５０℃の範囲で加熱後、熱間圧延を
行って（Ａｒ３− ５ ０ ）〜（Ａｒ３＋１ ０ ０
）℃の範囲で圧延を終了し、その後５５０〜８００℃
の範囲で巻き取り、これを酸洗してトータル圧下率６０
〜９０％の範囲の冷間圧延を行った後、浸炭雰囲気ガス
中で再結晶温度以１の温度で連続焼鈍を行うことを持徴
とする耐２次加工脆性に優れた深絞り川冷延鋼板の製造
方法を要旨とするものである。That is, the present invention provides C:Q. Q07% or less, Mn: 0
．． 05-0.50%, P:Ol. 2% or less, S: 0.0
15% or less, so1. Al: 0.005-0.05%,
Containing N: 0.006% or less, and further adding Ti and Nb alone or in combination, effective Tl amount (T) according to the following formula (1)
The relationship between the amount of Nb and the amount of C is expressed by the following formula (2) Ti*=totalTi − ((48/32)
S + (48/14) X N)…(1) 1≦(Ti*/48+ Nb/93)/ (C/12)
≦4.5...Contains within a range that satisfies (2), and if necessary, further contains B: 0.0 0 0 1 to 0.0 0 3 0
%, with the remainder consisting of Fe and unavoidable impurities, is heated in the range of 1000 to 1250°C and then hot rolled to form (Ar3-50) to (Ar3+100).
)℃, then 550~800℃
Wind it up in the range of
Deep drawing river cold rolling with excellent resistance to secondary work brittleness, which is characterized by cold rolling in the range of ~90% and then continuous annealing at a temperature higher than the recrystallization temperature in a carburizing atmosphere gas. The gist of this article is a method for manufacturing steel plates.
以下に本発明を更に詳細に説明する。The present invention will be explained in more detail below.
（作用）
本発明は、要するに、前述の如く理論上不可能とされて
いた技術に対して極低炭素鋼を用い、且つ、耐２次加工
脆性のために粒界の欠陥を埋めるのに必要なＣ量２〜１
５ｐｐｍを確保するならば、連続焼鈍でも可能であるこ
とを見い出したものである。この理由は、Ｃの侵入は粒
内拡散でなく、その速度が１０倍程度速い粒界拡散でな
されたものであり、更に粒界純度の非常に高い極低炭素
鋼であれば、その拡散速度が更に上がるため、連続焼鈍
において、焼鈍前に固溶Ｃ量が零であったものが、まず
粒界に、次いで粒内に所定量のＣｉを確保することがで
きることによるものである。(Function) In short, the present invention uses ultra-low carbon steel for the technology that was considered theoretically impossible as described above, and also uses the technology necessary to fill grain boundary defects in order to resist secondary work brittleness. C amount 2-1
It was discovered that continuous annealing is possible as long as 5 ppm is maintained. The reason for this is that the penetration of C is not through intragranular diffusion, but through grain boundary diffusion, which is about 10 times faster; This is due to the fact that in continuous annealing, the amount of solid solute C, which was zero before annealing, can be secured first at the grain boundaries and then within the grains.
まず、本発明における鋼の化学成分限定理由について説
明する。First, the reason for limiting the chemical composition of steel in the present invention will be explained.
Ｃ：
Ｃは、その含有量が増大するにつれてＣを固定するＴｉ
．Ｎｂの添加量が増加し、製造費用の増加につながる。C: C is Ti that fixes C as its content increases
．． The amount of Nb added increases, leading to an increase in manufacturing costs.
更にＴｉＣ及びＮｂＣ析出量が増大し粒或長を阻害して
ｒ値が劣化するので、Ｃ含有量は少ないほどよく、上限
値を０．０ ０ ７％とする。Furthermore, the amount of TiC and NbC precipitated increases, inhibiting grain elongation and deteriorating the r value. Therefore, the lower the C content, the better, and the upper limit is set at 0.007%.
なお、製鋼技術上の観点からＣ含有量の下限値は０．０
０ ０ ５％とするのが望ましい。In addition, from the viewpoint of steel manufacturing technology, the lower limit of C content is 0.0
It is desirable to set it to 0.05%.
一７
Ｍｎ：
Ｍｎは熱間脆性の防止を主目的に添加されるが、０．０
５％より少ないとその効果が得られず、方、添加量が多
すぎると延性を劣化させるので、その含有量は０．０５
〜０．５０％の範囲とする。-7 Mn: Mn is added mainly to prevent hot embrittlement, but 0.0
If it is less than 5%, the effect cannot be obtained, while if it is added too much, the ductility deteriorates, so the content should be 0.05%.
The range is 0.50%.
Ｐ：
Ｐは、ｒ値の低下を伴うことなく、鋼強度を高める効果
を有するが、粒界に偏析し２次加工脆性を起こし易くな
るので、その含有量は０．１２％以下に抑制する。P: P has the effect of increasing steel strength without reducing the r value, but it segregates at grain boundaries and tends to cause secondary work embrittlement, so its content should be suppressed to 0.12% or less. .
Ｓ：
Ｓは、Ｔｉと結合してＴｉＳを形或するので、その含有
量が増大するとＣ．Ｎを固定するのに必要なＴｉ量が増
大する。またＭｎＳ系の伸長した介在物が増加して局部
延性を劣化させるので、その含有量は０．０ １ ５％
以下に抑制する。S: S combines with Ti to form TiS, so when its content increases, C. The amount of Ti required to fix N increases. In addition, MnS-based elongated inclusions increase and deteriorate local ductility, so the content should be 0.015%.
Suppress below.
Ａｌ：
．ＡＩ２は溶鋼の脱酸を目的に添加されるが、その含有
量がｓｏｌ．Ａｌで０．０ ０ ５％より少ないと、そ
の目的が達威されず、一方、０．０５％を超え８
ると脱酸効果が飽和すると共にＡｌ２０３介在物が増加
して加工或形性を劣化させる。したがって、その含有量
はｓｏｌ．Ａｌで０．０ ０ ５ 〜０．０ ５％の範
囲とする。Al: . AI2 is added for the purpose of deoxidizing molten steel, but its content is sol. If the Al content is less than 0.005%, the purpose will not be achieved; on the other hand, if it exceeds 0.05%8, the deoxidizing effect will be saturated and the number of Al203 inclusions will increase, impairing processability. deteriorate. Therefore, its content is sol. The content of Al is in the range of 0.005 to 0.05%.
Ｎ：
Ｎは、Ｔ１と結合してＴｉＮを形成するので、その含有
量が増大するとＣを固定するのに必要なＴｉ量が増大す
る。またＴｊＮ析出量が増加して粒或長が咀杏されｒ
｛Ｉｆｆが劣化する。したがって、その含有量は少ない
ほど好ましく、０．０ ０ ６％以下に抑制する。N: Since N combines with T1 to form TiN, as its content increases, the amount of Ti required to fix C increases. In addition, the amount of TjN precipitation increases and the grain length is reduced.
{Iff deteriorates. Therefore, the content is preferably as low as possible, and is suppressed to 0.006% or less.
Ｔｉ． Ｎｂ：
Ｔｉ．ＮｂはＣ．Ｎを固定することによってｒ値を高め
る作用がある。この場合、前述の如＜ＴｉはＳ，Ｎと結
合してＴｉＳ．ＴｉＮを形或するので、製品におけるＴ
ｉ量は、次式（１）で計算される有効Ｔｉ量（Ｔｉ＊）
として換算される量にて考慮する必要がある。Ti. Nb: Ti. Nb is C. Fixing N has the effect of increasing the r value. In this case, as described above, <Ti is combined with S and N to form TiS. Since it is made of TiN, the T in the product is
The i amount is the effective Ti amount (Ti*) calculated by the following formula (1)
It is necessary to consider the amount converted as
Ｔｉ＊＝ｔｏｔａｌＴｉ （（４８／３２）×Ｓ＋（
４８／１４）×Ｎ｝…（１）
したがって、本発明の口的に対してはＴｉ４、Ｎｂ量と
Ｃ量との関係が（２）式
１≦（Ｔｉ＊／４８＋ Ｎｂ／９３）／ （Ｃ／１２）
≦４．５…・（２）を満足する範囲で含有する必要があ
る。この（２）式の値が１より小さいとＣ．Ｎを充分に
固定することができず、ｒ値を劣化させる。一方、４．
５を超えるとｒ値を高める作用が飽和すると共に、後工
程の浸炭雰囲気焼鈍時に侵入したＣが、固溶しているＴ
ｊ或いはＮｂとすぐに結合してしまい、Ｃの粒界偏析を
阻止するので、耐２次加工脆性の防止が得られず、また
過剰のＴｉ．Ｎｂによる硬化のために加工性も劣化し、
コス１−アップにもつながる。Ti*=totalTi ((48/32)×S+(
48/14)×N}...(1) Therefore, in terms of the present invention, the relationship between Ti4, Nb amount and C amount is expressed as (2) Equation 1≦(Ti*/48+Nb/93)/( C/12)
≦4.5...It is necessary to contain the content within a range that satisfies (2). If the value of this formula (2) is smaller than 1, C. N cannot be fixed sufficiently and the r value deteriorates. On the other hand, 4.
When it exceeds 5, the effect of increasing the r value is saturated, and the C that has entered during the subsequent process of annealing in a carburizing atmosphere becomes a solid solution of T.
Ti or Nb immediately binds to prevent grain boundary segregation of C, making it impossible to prevent secondary work brittleness. Workability also deteriorates due to hardening due to Nb,
This also leads to a 1-up in cost.
Ｂ：
Ｂは耐２次加工脆性に対して有効な元素であるので、必
要に応じて添加することができる。添加する場合、その
効果を得るためには少なくとも０．０００１％以上が必
要であるが、０．０ ０ ３ ０％を超えるとその効果
は飽和し、４つｒ値を低下させるので、その添加量は０
．０００１−０．００３Ｏ％の範囲とする。B: Since B is an effective element for secondary work brittleness resistance, it can be added as necessary. When added, at least 0.0001% or more is required to obtain the effect, but if it exceeds 0.0030%, the effect is saturated and the r value decreases, so the addition The amount is 0
．． The range is 0001-0.003O%.
次に本発明の製造方法について説明する。Next, the manufacturing method of the present invention will be explained.
」一記化学成分を有する鋼は、常法により溶解、ｉｇ造
するが、続く熱■圧延は特定条件にて行う必要がある。Steel having the chemical composition listed above is melted and produced using conventional methods, but the subsequent hot rolling must be carried out under specific conditions.
すなわち、工○ＯＯ〜１２５０℃に加熱した後、仕上温
度を（Ａｒ． − ５ ０ ）− （Ａｒ３＋ １ ０
０ ）℃の範囲で熱間圧延を行う。これは、ｒ値向」
二の観点から熱延板での結晶粒径の細粒化と集合組織の
ランダム化が必要であるためであり、必ずしも仕上温度
はＡｒ３点以上でなくてもよい。したがって、仕上温度
は（Ａｒ３５ ０ ）−（Ａｒ３ ＋ １ ０ ０ ）
゜Ｃの範囲とする。That is, after heating to ○OO~1250°C, the finishing temperature was set to (Ar. - 50) - (Ar3+ 10
Hot rolling is performed in the range of 0)°C. This is the r-value direction.”
This is because, from the second point of view, it is necessary to reduce the grain size and randomize the texture in the hot-rolled sheet, and the finishing temperature does not necessarily have to be Ar 3 or higher. Therefore, the finishing temperature is (Ar35 0 ) - (Ar3 + 1 0 0 )
The range is °C.
熱間圧延後の巻取温度は、鋼中の固ｉ＠ ｃ ． Ｎを
炭窒化物として固定するために５５０〜８ ０ ０ ℃
の範囲にする必要がある。The coiling temperature after hot rolling is determined by the hardness of the steel i@c. 550-800°C to fix N as carbonitride
It needs to be within the range.
次いで、冷間圧延においては、ｒ値に有利な（１１．１
）面方位集合組織を発達させるために、６０〜９０％の
トータル圧延率で行うことが必要である。Then, in cold rolling, the r value is favorable (11.1
) In order to develop the surface orientation texture, it is necessary to carry out rolling at a total rolling ratio of 60 to 90%.
１１−
この冷間圧延後、浸炭雰囲気ガス中で丙結晶温度以上の
範囲で連続焼鈍を行い、ｒ値に有利な（］．１．１）面
方位に集合組織を形成させる。11- After this cold rolling, continuous annealing is performed in a carburizing atmosphere gas in a range of C crystallization temperature or higher to form a texture in the (].1.1) plane orientation that is advantageous for the r value.
既に知られているように、ｒ｛直は土として鋼の（１１
１．）面方位集合組織に依存しているが、本発明におい
て再結晶焼鈍前に４ユ記巻取処理によって固溶Ｃ及び固
溶Ｎを完全に除くのは、上記の集合組織を得るためであ
る。しかも、一旦、再結晶が完了し集合組織が形成され
れば、その後に侵入するＣはｒ値には悪影響を与えない
。浸炭雰囲気中より侵入したＣのうち’■” ｊ Ｃ
． Ｎ ｂとしてＩｉ１１１ ＆されなかったＣが粒界
に偏析して耐２次加工脆性を改善するのである。As is already known, r
1. ) Although it depends on the plane orientation texture, in the present invention, solid solution C and solid solution N are completely removed by the 4 U coiling process before recrystallization annealing in order to obtain the above texture. . Furthermore, once recrystallization is completed and a texture is formed, C that invades thereafter does not have a negative effect on the r value. Of the C that entered from the carburizing atmosphere, '■'' j C
．． As Nb, Ii111 & C that is not converted segregates at the grain boundaries and improves the secondary work brittleness resistance.
連続焼鈍の雰囲気にはカーボンポテンシャルを制御した
浸炭ガスを用い、目的とする浸炭量はカーボンポテンシ
ャル、焼鈍温度、焼鈍時間の組合せを選択することによ
り制御し、耐２次加工脆性のために粒界の欠陥を埋める
のに必要なＣ量が２〜１５ｐｐｍとなるような条件で」
二記連続焼鈍を行えばよい。２ ｐｐｍよりも少ないと
耐２次加］二肌性１２
を得るために粒界の欠陥を狸めるのに必要なＣｉが不足
し、一方、１５ｐｐｍを超えると伸び等の加工性が劣化
し、また連続焼鈍の通板速度を低下させねばならず、坐
産＋ｌの低下を］ｆ１＜ので望ましくない。連続焼鈍炉
の炉内滞留時間は２ ｓｅｃ〜２ｍｉｎの範囲が好まし
い。A carburizing gas with a controlled carbon potential is used in the continuous annealing atmosphere, and the desired amount of carburizing is controlled by selecting a combination of carbon potential, annealing temperature, and annealing time. under conditions such that the amount of C required to fill the defects is 2 to 15 ppm.
Two consecutive annealing steps may be performed. If it is less than 2 ppm, there will be insufficient Ci to eliminate grain boundary defects in order to obtain [secondary stress resistance], while if it exceeds 15 ppm, workability such as elongation will deteriorate. , it is also necessary to reduce the threading speed during continuous annealing, which is undesirable because the locus +l decreases as ]f1<. The residence time in the continuous annealing furnace is preferably in the range of 2 seconds to 2 minutes.
次に本発明の実施例を示す。Next, examples of the present invention will be shown.
（実施例）
第］表に示す化学或分を有する｛Ｉ（試鋼を１２５０″
Ｃで３０分間加熱して溶体化処理を行−）た後、仕上温
度を４１ ０ ０ ℃で熱間ハ：延を終了し、その後７
５０℃で巻取り処理を行った。(Example) {I (test steel 1250″
After performing solution treatment by heating at C for 30 minutes, hot rolling was completed at a finishing temperature of 4100 C, and then 7
Winding treatment was performed at 50°C.
次いで、酸洗後、圧下率７５％で冷間圧延を行い、浸炭
雰囲気ガス中及び不活性ガス中において連続焼鈍として
８５０℃で１分間の再結晶焼鈍を行い、約７０℃／Ｓの
冷却速度で４． Ｏ Ｏ ℃まで冷却した後、その温度
で３分間の過時効処理を施し、１−％のスキンパスを行
った。なお、過時効処理及びスキンパスは、現状の製造
工程を想定して行ったものであり、必要に応して行えば
よい。Next, after pickling, cold rolling was performed at a reduction rate of 75%, and recrystallization annealing was performed at 850°C for 1 minute as continuous annealing in a carburizing atmosphere gas and an inert gas, and the cooling rate was approximately 70°C/S. So 4. After cooling to 00° C., an overaging treatment was performed at that temperature for 3 minutes, and a 1% skin pass was performed. Note that the over-aging treatment and the skin pass were performed assuming the current manufacturing process, and may be performed as necessary.
得られた冷延鋼板の機械的性質と２次加工脆性限界温度
を第２表に示すと共に、一部について第１図〜第３図に
整理して示す。The mechanical properties and secondary working brittleness limit temperatures of the obtained cold-rolled steel sheets are shown in Table 2, and some of them are also summarized in FIGS. 1 to 3.
なお、脆性試験は、総絞り比２．７でカップ戊形して得
られたカップを：３ ５ ｎｌ Ｉｌｌ １ｌ″６さに
１・リムした後、各試験爪（度の昂媒１１目こノＪソゾ
を；１７ｔいて旧角４０゜の円錐ポンチに押し込んで脆
性破壊の発生しない眼昇温度を４１リ走し、これを２次
加ユｌ Ｉｆｆａ性限界温度とした。In the brittleness test, the cup obtained by shaping the cup at a total drawing ratio of 2.7 was rimmed to 3 5 nl 1 l''6, and then each test nail (11 times of degree of aphrodisiac) was The material was pressed into a conical punch with an old angle of 40° using 17 tons and the temperature rise at 41°C without causing brittle fracture was determined, and this was taken as the critical temperature for secondary compression.
第２表より明らかなとおり、本発明例はいずれも、深絞
り用冷延鋼板としての要求を損ねることなく、耐２次加
工脆性が改善されていることがわかる。As is clear from Table 2, all of the examples of the present invention have improved secondary work brittleness without impairing the requirements for cold-rolled steel sheets for deep drawing.
一方、不活性ガス中で連続焼鈍を施した比較例は、耐２
次加工脆性に劣っており、また浸炭雰囲気ガス中で連続
焼鈍を行った比較例は、本発明範囲外の化学或分を有し
ているため、プレス成形性或いは耐２次加工脆性のいず
れかが劣っている。On the other hand, the comparative example subjected to continuous annealing in an inert gas has a resistance of 2.
The comparative example, which was continuously annealed in a carburizing atmosphere gas, had some chemical content outside the scope of the present invention, so it had poor press formability or secondary work brittleness. is inferior.
なお、第１図はＰ添加量が０．０ １ ５％以下の鋼に
おいて（Ｔｉ＊／４８＋Ｎｂ／９３）／（Ｃ／１２）の
イ直とｒ値との関係を整理したものであって、（Ｔ１＊
／４８＋ Ｎｂ／９３）／（Ｃ／１２）の値が４．５を
超えるとｒ値がほぼ飽和することがわかる。Furthermore, Figure 1 summarizes the relationship between the a value of (Ti*/48+Nb/93)/(C/12) and r value in steel with P addition of 0.015% or less. , (T1*
It can be seen that when the value of /48+Nb/93)/(C/12) exceeds 4.5, the r value is almost saturated.
第２図は第］図の場合と同じ鋼において（Ｔｊ＊／４８
＋Ｎｂ／９３）／（Ｃ／１２）の位と２次加工脆性眼Ｊ
ｕｌ．Ｍ１Ｌ度との関係を整ＪＩＪＩ Ｌ／たものであ
り、木発明眺囲内の化学戊分を有する鋼において浸炭雰
囲気ガス中で連続焼鈍することにより、２次加工脆性限
界温度が低下することがわかる。Figure 2 shows the same steel as in Figure 2 (Tj*/48
+Nb/93)/(C/12) and secondary processing brittle eye J
ul. The relationship between M1L degree and JIJI L/ is adjusted, and it can be seen that the secondary processing brittleness limit temperature is lowered by continuous annealing in a carburizing atmosphere gas for steel with a chemical fraction within the wood invention range. .
第３図はＰ添加鋼におけるＰ添加量と２次加工脆性限界
温度との関係を整理したものであり、本発明範囲内のＰ
添加量を有する鋼において浸炭雰囲気ガス中で連続焼鈍
することにより，２次加工脆性限界温度が低下すること
がわかる。Figure 3 summarizes the relationship between the amount of P added and the secondary working brittleness limit temperature in P-added steel, and shows that the P content within the range of the present invention is
It can be seen that the secondary processing brittleness limit temperature decreases by continuous annealing in a carburizing atmosphere gas in a steel with an additive amount.
【以下余〔門
（発明の効果）
以上詳述したように、本発明によれば、極低炭素鋼を用
い、且つその化学戒分を規制すると具に圧延条件を規制
することにより、連続焼鈍前の固溶Ｃ．Ｎを零として、
次いで浸炭雰囲気ガス中で連続焼鈍を行うので、深絞り
用冷延鋼板として要求されるプレス或形性を損なうこと
なく、耐２次加工脆性に優れた冷延鋼板を得ることがで
き、しかも生産性が高い。[The following is a summary of the effects of the invention: As described in detail above, according to the present invention, continuous annealing is possible by using ultra-low carbon steel and regulating its chemical precepts and rolling conditions. Previous solid solution C. Letting N be zero,
Continuous annealing is then carried out in a carburizing gas atmosphere, making it possible to obtain cold rolled steel sheets with excellent resistance to secondary work brittleness without impairing the pressability required for deep drawing cold rolled steel sheets. Highly sexual.
第１図〜第３図は実施例で得られた冷延鋼板の特性を整
理して１くす図であり、第１図はｌ）添加量が０．０１
．５％以下の鋼の（Ｔ ｉ ＊ ／ ４８ ＋ Ｎ ｂ
／ ９３）／（Ｃ／１２）の値とｒ値との関係を示し、
第２図は上記鋼の（Ｔｉ＊／４８＋Ｎｂ／９３）／（Ｃ
／１２）の値と２次加工脆性限界温度との関係を示し、
第３図はＰ添加鋼におけるＰ添加量と２次加工脆性限界
温度との関係を示している。Figures 1 to 3 are diagrams arranging the properties of the cold-rolled steel sheets obtained in the examples, and Figure 1 shows the l) addition amount of 0.01.
．． (T i * / 48 + N b
/93)/(C/12) and the r value,
Figure 2 shows the above steel (Ti*/48+Nb/93)/(C
/12) and the secondary processing brittleness limit temperature,
FIG. 3 shows the relationship between the amount of P added and the secondary working brittleness limit temperature in P-added steel.
Claims (2)
、Ｍｎ：０．０５〜０．５０％、Ｐ：０．１２％以下、
Ｓ：０．０１５％以下、ｓｏｌ．Ａｌ：０．００５〜０
．０５％、Ｎ：０．００６％以下を含有し、更にＴｉ及
びＮｂの単独又は複合添加で、下式（１）に従う有効Ｔ
ｉ量（Ｔｉ＊と表す）及びＮｂ量とＣ量との関係が下式
（２） Ｔｉ＊＝ｔｏｔａｌＴｉ−｛（４８／３２）×Ｓ＋（４
８／１４）×Ｎ｝…（１） １≦（Ｔｉ＊／４８＋Ｎｂ／９３）／（Ｃ／１２）≦４
．５…（２）を満足する範囲で含有し、残部がＦｅ及び
不可避的不純物よりなる鋼を、１０００〜１２５０℃の
範囲で加熱後、熱間圧延を行って（Ａｒ＿３−５０）〜
（Ａｒ＿３＋１００）℃の範囲で圧延を終了し、その後
５５０〜８００℃の範囲で巻き取り、これを酸洗してト
ータル圧下率６０〜９０％の範囲の冷間圧延を行った後
、浸炭雰囲気ガス中で再結晶温度以上の温度で連続焼鈍
を行うことを特徴とする耐２次加工脆性に優れた深絞り
用冷延鋼板の製造方法。(1) In weight% (the same applies hereinafter), C: 0.007% or less, Mn: 0.05 to 0.50%, P: 0.12% or less,
S: 0.015% or less, sol. Al: 0.005~0
．． 05%, N: 0.006% or less, and furthermore, by adding Ti and Nb alone or in combination, the effective T according to the following formula (1)
The relationship between the amount of i (expressed as Ti*), the amount of Nb, and the amount of C is expressed by the following formula (2): Ti*=totalTi−{(48/32)×S+(4
8/14)×N}...(1) 1≦(Ti*/48+Nb/93)/(C/12)≦4
．． 5... A steel containing (2) in a range that satisfies the above, with the remainder consisting of Fe and unavoidable impurities, is heated in a range of 1000 to 1250°C and then hot rolled (Ar_3-50) to
After finishing rolling in the range of (Ar_3+100)℃, it is then wound up in the range of 550 to 800℃, pickled, cold rolled in the range of 60 to 90% in total reduction, and then A method for producing a cold-rolled steel sheet for deep drawing with excellent resistance to secondary work brittleness, characterized in that continuous annealing is performed at a temperature equal to or higher than the recrystallization temperature.
含有する請求項１に記載の方法。(2) The method according to claim 1, wherein the steel contains B: 0.0001 to 0.0030%.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1230873A JPH0784618B2 (en) | 1989-09-05 | 1989-09-05 | Method for producing cold-rolled steel sheet for deep drawing excellent in secondary processing brittleness resistance |
| EP90115249A EP0421087B1 (en) | 1989-08-09 | 1990-08-08 | Method of manufacturing a steel sheet |
| CA002022907A CA2022907C (en) | 1989-08-09 | 1990-08-08 | Method of manufacturing a steel sheet |
| DE69014532T DE69014532T2 (en) | 1989-08-09 | 1990-08-08 | Process for the production of a steel sheet. |
| US07/564,756 US5085714A (en) | 1989-08-09 | 1990-08-09 | Method of manufacturing a steel sheet |
| KR1019900012246A KR930001519B1 (en) | 1989-08-09 | 1990-08-09 | Method of manufacturing a steel sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1230873A JPH0784618B2 (en) | 1989-09-05 | 1989-09-05 | Method for producing cold-rolled steel sheet for deep drawing excellent in secondary processing brittleness resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0394020A true JPH0394020A (en) | 1991-04-18 |
| JPH0784618B2 JPH0784618B2 (en) | 1995-09-13 |
Family
ID=16914647
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1230873A Expired - Lifetime JPH0784618B2 (en) | 1989-08-09 | 1989-09-05 | Method for producing cold-rolled steel sheet for deep drawing excellent in secondary processing brittleness resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0784618B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100470643B1 (en) * | 2000-12-05 | 2005-03-07 | 주식회사 포스코 | A high strength cold rolled steel sheet with excellent drawability and secondary working brittleness resistance, and a method for manufacturing it |
| KR100470644B1 (en) * | 2000-12-06 | 2005-03-07 | 주식회사 포스코 | A method for manufacturing deep drawing cold-rolled steel sheet with excellent secondary working brittleness resistance and press formability |
| KR101149269B1 (en) * | 2009-04-27 | 2012-05-25 | 현대제철 주식회사 | Method for producing of hot-rolled steel sheet having cold rolling |
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| JPS5974232A (en) * | 1982-10-20 | 1984-04-26 | Nippon Steel Corp | Production of bake hardenable galvanized steel sheet for ultradeep drawing having extremely outstanding secondary processability |
| JPS59140333A (en) * | 1983-01-28 | 1984-08-11 | Nippon Steel Corp | Manufacture of cold rolled steel sheet for deep drawing with superior secondary workability and surface treatability |
| JPS60149729A (en) * | 1984-01-11 | 1985-08-07 | Kawasaki Steel Corp | Production of cold rolled steel sheet for press forming |
| JPS61119621A (en) * | 1984-11-16 | 1986-06-06 | Nippon Steel Corp | Manufacture of cold rolled steel sheet for deep drawing |
| JPS6237341A (en) * | 1985-08-12 | 1987-02-18 | Kawasaki Steel Corp | Hot-rolled steel plate for superdrawing having superior resistance to secondary operation brittleness |
| JPS6338556A (en) * | 1986-08-04 | 1988-02-19 | Nisshin Steel Co Ltd | Cold rolled steel sheet for deep drawing having superior resistance to cracking by secondary working and its manufacture |
| JPS6386819A (en) * | 1986-09-30 | 1988-04-18 | Kawasaki Steel Corp | Production of cold rolled steel sheet for deep drawing |
-
1989
- 1989-09-05 JP JP1230873A patent/JPH0784618B2/en not_active Expired - Lifetime
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5974232A (en) * | 1982-10-20 | 1984-04-26 | Nippon Steel Corp | Production of bake hardenable galvanized steel sheet for ultradeep drawing having extremely outstanding secondary processability |
| JPS59140333A (en) * | 1983-01-28 | 1984-08-11 | Nippon Steel Corp | Manufacture of cold rolled steel sheet for deep drawing with superior secondary workability and surface treatability |
| JPS60149729A (en) * | 1984-01-11 | 1985-08-07 | Kawasaki Steel Corp | Production of cold rolled steel sheet for press forming |
| JPS61119621A (en) * | 1984-11-16 | 1986-06-06 | Nippon Steel Corp | Manufacture of cold rolled steel sheet for deep drawing |
| JPS6237341A (en) * | 1985-08-12 | 1987-02-18 | Kawasaki Steel Corp | Hot-rolled steel plate for superdrawing having superior resistance to secondary operation brittleness |
| JPS6338556A (en) * | 1986-08-04 | 1988-02-19 | Nisshin Steel Co Ltd | Cold rolled steel sheet for deep drawing having superior resistance to cracking by secondary working and its manufacture |
| JPS6386819A (en) * | 1986-09-30 | 1988-04-18 | Kawasaki Steel Corp | Production of cold rolled steel sheet for deep drawing |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100470643B1 (en) * | 2000-12-05 | 2005-03-07 | 주식회사 포스코 | A high strength cold rolled steel sheet with excellent drawability and secondary working brittleness resistance, and a method for manufacturing it |
| KR100470644B1 (en) * | 2000-12-06 | 2005-03-07 | 주식회사 포스코 | A method for manufacturing deep drawing cold-rolled steel sheet with excellent secondary working brittleness resistance and press formability |
| KR101149269B1 (en) * | 2009-04-27 | 2012-05-25 | 현대제철 주식회사 | Method for producing of hot-rolled steel sheet having cold rolling |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0784618B2 (en) | 1995-09-13 |
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