JP2018044183A - Production metho of plated steel sheet - Google Patents
Production metho of plated steel sheet Download PDFInfo
- Publication number
- JP2018044183A JP2018044183A JP2016177281A JP2016177281A JP2018044183A JP 2018044183 A JP2018044183 A JP 2018044183A JP 2016177281 A JP2016177281 A JP 2016177281A JP 2016177281 A JP2016177281 A JP 2016177281A JP 2018044183 A JP2018044183 A JP 2018044183A
- Authority
- JP
- Japan
- Prior art keywords
- steel sheet
- atmosphere
- plating
- seconds
- soaking
- 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.)
- Pending
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 102
- 239000010959 steel Substances 0.000 title claims abstract description 102
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 33
- 238000007747 plating Methods 0.000 claims abstract description 59
- 238000002791 soaking Methods 0.000 claims abstract description 49
- 238000000137 annealing Methods 0.000 claims abstract description 36
- 229910001335 Galvanized steel Inorganic materials 0.000 claims abstract description 19
- 239000008397 galvanized steel Substances 0.000 claims abstract description 19
- 238000000034 method Methods 0.000 claims description 63
- 239000007789 gas Substances 0.000 claims description 42
- 238000001816 cooling Methods 0.000 claims description 23
- 229910052739 hydrogen Inorganic materials 0.000 claims description 22
- 239000001257 hydrogen Substances 0.000 claims description 20
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 18
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 18
- 229910052760 oxygen Inorganic materials 0.000 claims description 18
- 239000001301 oxygen Substances 0.000 claims description 18
- 238000010438 heat treatment Methods 0.000 description 16
- 229910004298 SiO 2 Inorganic materials 0.000 description 7
- 238000005246 galvanizing Methods 0.000 description 7
- 238000005554 pickling Methods 0.000 description 7
- 238000005275 alloying Methods 0.000 description 6
- 238000002474 experimental method Methods 0.000 description 6
- 238000005098 hot rolling Methods 0.000 description 6
- 238000005097 cold rolling Methods 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- 238000010521 absorption reaction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000014509 gene expression Effects 0.000 description 3
- 150000002431 hydrogen Chemical class 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 229910018137 Al-Zn Inorganic materials 0.000 description 2
- 229910018573 Al—Zn Inorganic materials 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000010960 cold rolled steel Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000007598 dipping method Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 238000001953 recrystallisation Methods 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000004320 controlled atmosphere Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 210000004894 snout Anatomy 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 238000005211 surface analysis Methods 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
Images
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
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
- C23C2/0224—Two or more thermal pretreatments
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/024—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by cleaning or etching
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/06—Zinc or cadmium or alloys based thereon
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
- C23C2/36—Elongated material
- C23C2/40—Plates; Strips
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Sheet Steel (AREA)
- Coating With Molten Metal (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Abstract
Description
本発明は、自動車部品等に用いられる溶融亜鉛めっき鋼板又は合金化溶融亜鉛めっき鋼板を製造する方法に関する。 The present invention relates to a method for producing a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet used for automobile parts and the like.
近年、自動車軽量化と衝突安全性の両立のため、高強度鋼の適用が進み、引張強度が５９０ＭＰａを超える鋼板の適用が拡大している。また、耐食性が要求されるアンダーボディーに使用される亜鉛めっき鋼板においても、さらなる高強度化が求められている。 In recent years, application of high-strength steel has progressed in order to achieve both vehicle weight reduction and collision safety, and the application of steel sheets having a tensile strength exceeding 590 MPa has been expanded. Further, higher strength is also demanded for galvanized steel sheets used for under bodies that require corrosion resistance.
ところで、高強度鋼板の自動車部品への適用に際しては、強度と成形性の両立が課題とされている。高強度鋼板では成形荷重が大きくなるため、成形時に割れが発生し易いという問題があるためである。そこで、鋼板において、強度と成形性を両立する技術が求められている。 By the way, when applying high-strength steel sheets to automobile parts, there is a problem of achieving both strength and formability. This is because a high-strength steel sheet has a problem that cracks are likely to occur during forming because the forming load becomes large. Therefore, there is a need for a technology that achieves both strength and formability in steel sheets.
この点、母材鋼板（素地鋼板）成分としてＳｉを添加することで、成形性が向上することが知られている。しかし、Ｓｉ添加鋼の溶融亜鉛めっき鋼板を製造する場合に、不めっきが発生し易いことが知られており、そのための対策が必要となる。 In this regard, it is known that the formability is improved by adding Si as a base steel plate (base steel plate) component. However, it is known that non-plating is likely to occur when a hot-dip galvanized steel sheet made of Si-added steel is produced, and measures for that are required.
これまでに、Ｓｉ添加鋼の不めっきを抑制する技術として、焼鈍工程の雰囲気制御により、Ｓｉ酸化物の生成を抑制する技術が知られている。例えば、特許文献１では、めっき性を良好にするために、Ｓｉ含有量：０．４〜２．０質量％を含む高強度鋼板に連続溶融亜鉛めっきを施す際に、鋼板を予熱し、次いで、直火還元炉で直火還元バーナーの空気比を０．６以上０．９未満とした還元雰囲気で鋼板を還元し、その後、水素還元を行う間接加熱炉で水分圧と水素分圧の対数ｌｏｇ（ＰＨ2Ｏ／ＰＨ2）が所定の条件を満たす雰囲気で鋼板を還元し、間接加熱炉からめっき設備入側のスナウト部まで間では別途所定の条件を満たす雰囲気として還元及び冷却を行い、連続溶融亜鉛めっきを施すことを特徴とする高強度溶融亜鉛めっき鋼板の製造方法が報告されている。 So far, as a technique for suppressing non-plating of Si-added steel, a technique for suppressing generation of Si oxide by controlling the atmosphere in an annealing process is known. For example, in Patent Document 1, in order to improve the plating property, when continuous hot-dip galvanizing is performed on a high-strength steel sheet containing Si content: 0.4 to 2.0% by mass, the steel sheet is preheated, The steel plate is reduced in a reducing atmosphere in which the air ratio of the direct-fire reduction burner is 0.6 or more and less than 0.9 in a direct-fire reduction furnace, and then the logarithm of moisture pressure and hydrogen partial pressure in an indirect heating furnace that performs hydrogen reduction log (PH 2 O / PH 2 ) reduces the steel sheet in an atmosphere that satisfies a predetermined condition, and performs reduction and cooling as an atmosphere that satisfies the predetermined condition between the indirect heating furnace and the snout portion on the plating equipment entry side, A method for producing a high-strength hot-dip galvanized steel sheet characterized by performing continuous hot-dip galvanizing has been reported.
一方、近年、均熱処理の後に均熱処理よりも低温で過時効処理を行うことで、鋼板の成形性を向上させる技術が開発されている。しかし、特許文献１では焼鈍工程で過時効帯を持つような加熱パターンは考慮されていない。 On the other hand, in recent years, a technique for improving the formability of a steel sheet has been developed by performing an overaging treatment at a lower temperature than the soaking after the soaking. However, Patent Document 1 does not consider a heating pattern having an overaging zone in the annealing process.
本発明は、上記の様な問題点に着目してなされたものであって、その目的は、Ｓｉを含む鋼板において過時効帯を有する加熱パターンを行っても、不めっきを発生しにくい鋼板を製造する方法を提供することである。 The present invention has been made paying attention to the problems as described above, and its purpose is to provide a steel sheet that is less likely to cause non-plating even if a heating pattern having an overaging zone is performed on a steel sheet containing Si. It is to provide a method of manufacturing.
本発明者らは鋭意検討を重ね、下記構成によって上記課題が解決できることを見出した。 The present inventors have made extensive studies and found that the above-described problems can be solved by the following configuration.
すなわち、本発明の一局面に係る鋼板の製造方法は、Ｓｉを含有する素地鋼板に、焼鈍処理およびめっき処理を連続的に行うことにより溶融亜鉛めっき鋼板又は合金化溶融亜鉛めっき鋼板を製造する方法であって、
前記焼鈍処理が、
鋼板を７００℃〜９５０℃の温度域で４０秒〜３６０秒間滞在させ、さらに雰囲気が７００℃以上では水素を３体積％以上含有し、かつ、初めて７００℃以上に達してから最初の４０秒間以上（最大で均熱工程の最後まで）において、ｐＯ２を酸素分圧（Ｐａ）、｛Ｓｉ｝をＳｉ含有量（質量％）とした場合に、式１：
（｛Ｓｉ｝）＾２×７．３×１０＾（−２２）≦ｐＯ２
を満たすガス雰囲気となるように制御する均熱工程と、
前記均熱工程の後に、鋼板を３００℃〜６７０℃の温度域で９０秒〜６００秒間滞在させ、雰囲気が前記均熱工程以降であって６７０℃以下の範囲において水素を３体積％以上含有し、露点が、ＤＰを露点（℃）、Ｔを保持温度（℃）とした場合に、下記式２：
ＤＰ≦０．０００７３×Ｔ２−０．４１×Ｔ＋３８
を満たすガス雰囲気となるように制御する過時効工程とを含むことを特徴とする。
That is, the method for producing a steel sheet according to one aspect of the present invention is a method for producing a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet by continuously subjecting a base steel sheet containing Si to annealing and plating. Because
The annealing treatment is
The steel plate is allowed to stay in a temperature range of 700 ° C. to 950 ° C. for 40 seconds to 360 seconds. Further, when the atmosphere is 700 ° C. or higher, it contains 3% by volume or more of hydrogen. (Up to the end of the soaking step at the maximum), when pO 2 is oxygen partial pressure (Pa) and {Si} is Si content (mass%), formula 1:
({Si}) ^ 2 × 7.3 × 10 ^ (− 22) ≦ pO 2
A soaking process that controls the gas atmosphere to satisfy
After the soaking step, the steel plate is allowed to stay in a temperature range of 300 ° C. to 670 ° C. for 90 seconds to 600 seconds, and the atmosphere is after the soaking step and contains 3% by volume or more of hydrogen in a range of 670 ° C. or less. When the dew point is DP as the dew point (° C.) and T as the holding temperature (° C.), the following formula 2:
DP ≦ 0.00073 × T 2 −0.41 × T + 38
And an overaging process for controlling the gas atmosphere to satisfy the above condition.
また、前記製造方法において、前記素地鋼板のＳｉ含有量が０．３〜２．７％（質量％の意味。以下、特に言及しない限り、成分組成において同じ）であることが好ましい。 Moreover, in the said manufacturing method, it is preferable that Si content of the said base steel plate is 0.3-2.7% (meaning of the mass%. Hereinafter, unless it mentions especially, it is the same in a component composition).
さらに、前記製造方法において、前記均熱工程の後であって、前記過時効工程の前に、冷却工程をさらに含むことが好ましい。 Furthermore, the manufacturing method preferably further includes a cooling step after the soaking step and before the overaging step.
本発明によれば、成形性に優れつつ、かつ、めっき性にも優れた鋼板の製造方法を提供することができる。 According to the present invention, it is possible to provide a method for producing a steel sheet that is excellent in formability and excellent in plating properties.
発明者らは、過時効帯を持つ加熱パターンの場合には、従来のように雰囲気において露点を一定以上に制御するだけでは不めっきの発生を十分に抑制できないことを把握し、鋭意検討を重ねた。その結果、均熱帯の雰囲気を従来のように高い露点に制御することに加え、過時効帯の露点を逆に低露点に制御することによって、はじめてＳｉ添加鋼の過時効工程後の不めっきの発生を抑制可能であることを見出した。そして、当該知見に基づいてさらに研究を重ね、本発明に至った。 In the case of a heating pattern with an overaging zone, the inventors have grasped that the occurrence of non-plating cannot be sufficiently suppressed by simply controlling the dew point to a certain level or more in the atmosphere as in the prior art, and intensively studied. It was. As a result, in addition to controlling the soaking atmosphere to a high dew point as in the past, the over-aging zone dew point is controlled to a low dew point. It was found that the occurrence can be suppressed. And further research was repeated based on the said knowledge, and it came to this invention.
すなわち、本発明に係る鋼板の製造方法は、Ｓｉを含有する素地鋼板に、焼鈍処理およびめっき処理を連続的に行うことにより溶融亜鉛めっき鋼板又は合金化溶融亜鉛めっき鋼板を製造する方法であって、
前記焼鈍処理が、
鋼板を７００℃〜９５０℃の温度域で４０秒〜３６０秒間滞在させ、さらに雰囲気が７００℃以上では水素を３体積％以上含有し、かつ、初めて７００℃以上に達してから最初の４０秒間以上（最大で均熱工程の最後まで）において、ｐＯ２を酸素分圧（Ｐａ）、｛Ｓｉ｝をＳｉ含有量（質量％）とした場合に、式１：
（｛Ｓｉ｝）＾２×７．３×１０＾（−２２）≦ｐＯ２
を満たすガス雰囲気となるように制御する均熱工程と、
前記均熱工程の後に、鋼板を３００℃〜６７０℃の温度域で９０秒〜６００秒間滞在させ、雰囲気が前記均熱工程以降であって６７０℃以下の範囲において水素を３体積％以上含有し、露点が、ＤＰを露点（℃）、Ｔを保持温度（℃）とした場合に、下記式２：
ＤＰ≦０．０００７３×Ｔ２−０．４１×Ｔ＋３８
を満たすガス雰囲気となるように制御する過時効工程とを含むことを特徴とする。
That is, the method for producing a steel sheet according to the present invention is a method for producing a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet by continuously performing annealing treatment and plating treatment on a base steel sheet containing Si. ,
The annealing treatment is
The steel plate is allowed to stay in a temperature range of 700 ° C. to 950 ° C. for 40 seconds to 360 seconds. Further, when the atmosphere is 700 ° C. or higher, it contains 3% by volume or more of hydrogen. (Up to the end of the soaking step at the maximum), when pO 2 is oxygen partial pressure (Pa) and {Si} is Si content (mass%), formula 1:
({Si}) ^ 2 × 7.3 × 10 ^ (− 22) ≦ pO 2
A soaking process that controls the gas atmosphere to satisfy
After the soaking step, the steel plate is allowed to stay in a temperature range of 300 ° C. to 670 ° C. for 90 seconds to 600 seconds, and the atmosphere is after the soaking step and contains 3% by volume or more of hydrogen in a range of 670 ° C. or less. When the dew point is DP as the dew point (° C.) and T as the holding temperature (° C.), the following formula 2:
DP ≦ 0.00073 × T 2 −0.41 × T + 38
And an overaging process for controlling the gas atmosphere to satisfy the above condition.
本発明の製造方法によれば、鋼板の成形性を向上させ、さらに、従来問題となっていた不めっきの発生も抑制することができる。 According to the production method of the present invention, it is possible to improve the formability of the steel sheet and to suppress the occurrence of non-plating, which has been a problem in the past.
以下、本発明の実施の形態についてより具体的に説明するが、本発明はこれらに限定されるものではない。 Hereinafter, embodiments of the present invention will be described more specifically, but the present invention is not limited to these.
本発明は、Ｓｉを含有する素地鋼板に、焼鈍処理およびめっき処理を連続的に行うことにより溶融亜鉛めっき鋼板又は合金化溶融亜鉛めっき鋼板を製造する方法に関する。 The present invention relates to a method for producing a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet by continuously subjecting a base steel sheet containing Si to annealing and plating.
一般的に、焼鈍に供される鋼板は、連続鋳造で作られたスラブに熱間圧延、酸洗、冷間圧延を施すことで製造される。 Generally, a steel sheet to be annealed is manufactured by subjecting a slab made by continuous casting to hot rolling, pickling, and cold rolling.
〔焼鈍処理〕
まず、本実施形態の焼鈍処理工程について説明する。上述したように、本実施形態の焼鈍工程は、均熱工程と過時効工程を含む。さらに、前記均熱工程と前記過時効工程の間に、冷却工程を備えていてもよい。
[Annealing treatment]
First, the annealing process of this embodiment is demonstrated. As described above, the annealing process of the present embodiment includes a soaking process and an overaging process. Furthermore, a cooling step may be provided between the soaking step and the overaging step.
（均熱工程）
本実施形態において、均熱工程とは、７００℃〜９５０℃の温度域で４０秒〜３６０秒間、所定の条件となるように制御したガス雰囲気に鋼板を滞在させ、均熱処理を行う工程である。７００℃以上の温度帯における滞在時間が４０秒未満では、再結晶が不十分となり、鋼板の強度や加工性といった機械的特性が得られないおそれがある。より好ましい滞在時間の下限は６０秒である。一方、７００℃以上の温度域における滞在時間が長くなることは特に問題ないが、長過ぎても処理設備への負担やコストの観点で望ましくないため、３６０秒以下とする。より望ましくは３００秒以下である。
(Soaking process)
In the present embodiment, the soaking step is a step in which the soaking process is performed by allowing the steel sheet to stay in a gas atmosphere controlled so as to satisfy predetermined conditions in a temperature range of 700 ° C. to 950 ° C. for 40 seconds to 360 seconds. . If the residence time in the temperature range of 700 ° C. or higher is less than 40 seconds, recrystallization becomes insufficient, and mechanical properties such as strength and workability of the steel sheet may not be obtained. A more preferable lower limit of the staying time is 60 seconds. On the other hand, there is no particular problem in that the residence time in the temperature range of 700 ° C. or higher is long, but if it is too long, it is not desirable from the viewpoint of burden on the processing equipment and cost, so 360 seconds or less. More desirably, it is 300 seconds or less.
均熱工程において、温度が７００℃に達した後は、７００〜９５０℃の温度範囲で鋼板を保持する。この時の保持温度は、好ましくは８００℃以上である。また前記保持温度の下限値は、９５０℃以下であれば問題ないが、好ましくは９３０℃以下である。 In the soaking step, after the temperature reaches 700 ° C., the steel plate is held in a temperature range of 700 to 950 ° C. The holding temperature at this time is preferably 800 ° C. or higher. The lower limit of the holding temperature is not problematic as long as it is 950 ° C. or lower, but is preferably 930 ° C. or lower.
本実施形態の均熱工程においては、ガス雰囲気を、７００℃以上では水素を３体積％以上含有し、かつ、初めて７００℃以上に達してから最初の４０秒間以上（最大で均熱工程の最後まで）において、下記式１：
（｛Ｓｉ｝）＾２×７．３×１０＾（−２２）≦ｐＯ２
を満たすガス雰囲気となるように制御する。式中、ｐＯ２は酸素分圧（Ｐａ）、｛Ｓｉ｝はＳｉ含有量（質量％）を示す。
In the soaking process of this embodiment, the gas atmosphere contains 3% by volume or more of hydrogen at 700 ° C. or higher, and for the first 40 seconds or more after reaching 700 ° C. for the first time (maximum end of the soaking process). Until the following formula 1:
({Si}) ^ 2 × 7.3 × 10 ^ (− 22) ≦ pO 2
It controls so that it may become the gas atmosphere which satisfy | fills. In the formula, pO 2 represents oxygen partial pressure (Pa), and {Si} represents Si content (mass%).
均熱工程の雰囲気が上記ガス雰囲気に制御されていれば、鋼板が酸化しない程度に還元性を維持しつつ、露点制御によって適度な酸素分圧を確保することで、鋼板のＳｉを鋼板の内部で酸化させることができる。そのため、不めっきの阻害要因となるＳｉ酸化物が鋼板表面に生成されない。鋼板のＳｉ添加量が多いほど高い酸素分圧で酸素を供給しなければ鋼板内部でＳｉを酸化させることができず、鋼板表面にＳｉ酸化物が生成して不めっきを抑制できなくなる傾向がある。発明者が種々検討した結果、式１を満たす条件範囲であれば不めっきが回避できることを見出した。 If the atmosphere of the soaking process is controlled to the above-mentioned gas atmosphere, while maintaining reducibility to the extent that the steel sheet is not oxidized, by securing an appropriate oxygen partial pressure by dew point control, Si in the steel sheet is It can be oxidized with. Therefore, Si oxide which becomes a hindrance factor of non-plating is not produced | generated on the steel plate surface. As the amount of Si added to the steel sheet increases, Si cannot be oxidized inside the steel sheet unless oxygen is supplied at a high oxygen partial pressure, and there is a tendency that Si oxide is generated on the steel sheet surface and non-plating cannot be suppressed. . As a result of various studies by the inventor, it has been found that non-plating can be avoided as long as the condition range satisfies Expression 1.
式１中の酸素分圧ｐＯ２の上限は特に限定はされないが、安定して活性な鋼板表面を得るため、また焼鈍設備の酸化による損傷を抑えるため、１．２×１０＾（−１８）Ｐａ以下程度とすることが好ましい。より望ましくは、６．４×１０＾（−１９）Ｐａ以下である。 The upper limit of the oxygen partial pressure pO 2 in Equation 1 is not particularly limited, but in order to obtain a stable and active steel sheet surface and to suppress damage due to oxidation of the annealing equipment, 1.2 × 10 ^ (− 18) It is preferable to be about Pa or less. More desirably, it is 6.4 × 10 ^ (− 19) Pa or less.
７００℃以上の温度帯において、雰囲気中の水素濃度が３体積％未満の場合、ガス雰囲気を安定に制御することが困難になるため、３体積％以上含有させる。より好ましくは、５体積％以上含有させる。前記水素濃度の上限は特に限定されないが、水素ガスの使用コストという観点から、３０体積％以下であることが好ましい。より好ましくは、１５体積％以下である。 If the hydrogen concentration in the atmosphere is less than 3% by volume in a temperature range of 700 ° C. or higher, it is difficult to stably control the gas atmosphere. More preferably, 5 volume% or more is contained. The upper limit of the hydrogen concentration is not particularly limited, but is preferably 30% by volume or less from the viewpoint of the cost of using hydrogen gas. More preferably, it is 15 volume% or less.
なお、均熱工程の雰囲気中、Ｈ２以外の残部成分については、露点を制御するための加えられるＨ２Ｏガス、露点に影響を及ぼさない不活性ガス（Ｎ２、Ａｒ等）、およびＨ２、Ｈ２Ｏと平衡関係にある微量のＯ２ガスであり、さらにその他の成分は意図せず混入する微量の不純物ガスである。 In addition, in the atmosphere of the soaking process, the remaining components other than H 2 are H 2 O gas added to control the dew point, an inert gas (N 2 , Ar, etc.) that does not affect the dew point, and H 2 , a trace amount of O 2 gas in equilibrium with H 2 O, and other components are trace amounts of impurity gas that are unintentionally mixed.
（冷却工程）
上述したように、前記均熱工程後であって、後述の過時効工程を行う前に、冷却処理を行ってもよい。それにより、鋼板の強度と加工性のバランスをさらに向上させることができるという利点がある。
(Cooling process)
As described above, a cooling treatment may be performed after the soaking step and before performing the overaging step described below. Thereby, there exists an advantage that the balance of the intensity | strength and workability of a steel plate can be improved further.
冷却温度は特に限定されないが、２５０℃以下の温度まで冷却することが好ましい。より好ましくは２００℃以下である。 The cooling temperature is not particularly limited, but it is preferable to cool to a temperature of 250 ° C. or lower. More preferably, it is 200 degrees C or less.
冷却処理を行う場合、冷却温度の下限について限定はないが、過時効処理を行うために再度加熱する必要があるという観点から１００℃以上とすることが好ましい。より好ましくは１３０℃以上である。 When performing the cooling treatment, there is no limitation on the lower limit of the cooling temperature, but it is preferably 100 ° C. or higher from the viewpoint that it is necessary to heat again to perform the overaging treatment. More preferably, it is 130 ° C. or higher.
（過時効工程）
上記均熱工程または上記冷却工程の後に、均熱温度帯よりも低い３００℃〜６７０℃の温度域で９０秒〜６００秒間、所定の条件となるように制御したガス雰囲気に鋼板を滞在させ、過時効処理を行う工程である。前記滞在時間が９０秒未満になると、過時効処理の効果が得られないおそれがある。より好ましい滞在時間の下限は１２０秒である。一方、過時効処理の温度域における滞在時間が長くなることは問題ないが、長過ぎても処理設備への負担やコストの観点で望ましくないため、６００秒以下とする。より望ましくは４００秒以下である。
(Overaging process)
After the soaking step or the cooling step, the steel plate is allowed to stay in a gas atmosphere controlled so as to satisfy predetermined conditions in a temperature range of 300 ° C. to 670 ° C. lower than the soaking temperature zone for 90 seconds to 600 seconds, This is a process for performing overaging treatment. If the stay time is less than 90 seconds, the effect of the overaging treatment may not be obtained. A more preferable lower limit of the staying time is 120 seconds. On the other hand, there is no problem that the residence time in the temperature range of the overaging treatment becomes long, but if it is too long, it is not desirable from the viewpoint of the burden on the treatment equipment and the cost, so it is 600 seconds or less. More desirably, it is 400 seconds or less.
過時効工程において、温度が３００℃に達した後は、３００〜６７０℃の温度範囲で鋼板を保持する。この時の保持温度は、要求される機械的特性に応じて３００℃に達した後そのまま３００℃で保持してもよく、６００℃以上の温度で保持してもよい。また前記保持温度の下限値は、６７０℃以下であれば問題ないが、好ましくは６５０℃以下である。なお、６７０℃を超えると鋼組織の再結晶が生じ始めるため過時効工程の効果が得られない。また、３００℃未満の温度で保持しても温度が低すぎて過時効による組織変化が得られない。 In the overaging process, after the temperature reaches 300 ° C, the steel sheet is held in a temperature range of 300 to 670 ° C. The holding temperature at this time may be held at 300 ° C. as it is after reaching 300 ° C. according to the required mechanical properties, or may be held at a temperature of 600 ° C. or higher. Further, the lower limit of the holding temperature is not problematic as long as it is 670 ° C. or lower, but is preferably 650 ° C. or lower. If the temperature exceeds 670 ° C., recrystallization of the steel structure starts to occur, and the effect of the overaging process cannot be obtained. Moreover, even if it hold | maintains at the temperature of less than 300 degreeC, temperature is too low and the structure change by overaging cannot be obtained.
本実施形態の過時効工程（前記均熱工程以降であって６７０℃以下の範囲）において、雰囲気が水素を３体積％以上含有し、その露点が、下記式２：
ＤＰ≦０．０００７３×Ｔ２−０．４１×Ｔ＋３８
を満たすガス雰囲気となるように制御する。式中、ＤＰは露点（℃）、Ｔは上記保持温度（℃）を示す。
In the overaging process of the present embodiment (after the soaking process and in a range of 670 ° C. or less), the atmosphere contains 3% by volume or more of hydrogen, and the dew point is represented by the following formula 2:
DP ≦ 0.00073 × T 2 −0.41 × T + 38
The gas atmosphere is controlled so as to satisfy. In the formula, DP represents the dew point (° C.), and T represents the holding temperature (° C.).
上記露点（ＤＰ）の下限は特に定めないが、実際には不可避的に混入する微量酸素が存在するため、過剰に下げることは製造コストアップとなるため好ましくない。そこで露点は−６５℃以上程度とすることが望ましい。 The lower limit of the dew point (DP) is not particularly defined. However, since there is actually a trace amount of oxygen inevitably mixed in, it is not preferable to reduce the dew point excessively because the manufacturing cost increases. Therefore, it is desirable that the dew point is about −65 ° C. or higher.
均熱工程よりも低い温度域で実施される過時効工程では、雰囲気の露点が高いと不めっきが発生する場合がある。発明者らは種々検討した結果、前記の均熱工程で適正な雰囲気条件を満たす場合であっても、過時効工程において温度が低く、露点が高いほど不めっきが発生する傾向があることを見出した。さらに種々検討した結果、式２を満足する場合には不めっきが回避できることを見出した。露点が高いほど、また、温度が低いほど不めっきが発生するのは、雰囲気からの水蒸気の吸着等により鋼板表面の活性が失われ、めっきとの濡れ性を阻害するためと推定される。 In an overaging process performed in a temperature range lower than the soaking process, non-plating may occur if the dew point of the atmosphere is high. As a result of various studies, the inventors have found that even when the proper atmosphere condition is satisfied in the soaking process, the temperature is low in the overaging process, and the higher the dew point, the more the non-plating tends to occur. It was. Further, as a result of various studies, it was found that non-plating can be avoided when Expression 2 is satisfied. It is presumed that the higher the dew point and the lower the temperature, the more the non-plating occurs because the activity of the steel sheet surface is lost due to the adsorption of water vapor from the atmosphere and the like, and the wettability with the plating is hindered.
なお、過時効工程において雰囲気中の水素濃度が３体積％未満の場合、雰囲気を安定に制御できないため、３体積％以上含有させる。より好ましくは、５体積％以上含有させる。前記水素濃度の上限は特に限定されないが、水ガス供給のコストという観点から、３０体積％以下であることが好ましい。より好ましくは、１５体積％以下である。 In the overaging process, when the hydrogen concentration in the atmosphere is less than 3% by volume, the atmosphere cannot be stably controlled. More preferably, 5 volume% or more is contained. The upper limit of the hydrogen concentration is not particularly limited, but is preferably 30% by volume or less from the viewpoint of water gas supply cost. More preferably, it is 15 volume% or less.
なお、過時効工程の雰囲気中、Ｈ２以外および残部成分については、上述の式２を満たす範囲で含有する微量のＨ２ＯガスおよびＯ２ガス、さらに、その他の成分は露点に影響を及ぼさない不活性ガス（Ｎ２、Ａｒ等）、および意図しない微量の不純物ガスである。 In addition, in the atmosphere of the overaging process, with respect to components other than H2 and the remaining components, a very small amount of H 2 O gas and O 2 gas contained in a range satisfying the above-mentioned formula 2, and other components do not affect the dew point. An inert gas (N 2 , Ar, etc.) and an unintended trace amount of impurity gas.
（焼鈍処理における雰囲気制御）
上記各工程における加熱は例えばインダクションヒーターで行うことができ、また、冷却は５％Ｈ２−Ｎ２ガス等を用いて行うことができる。加熱・冷却を行う際は、冷却室と加熱室とを分け、その間をバルブで遮断することで冷却中に加熱炉内の雰囲気が変化することを避けることが好ましい。
(Atmosphere control in annealing treatment)
Heating in each of the above steps can be performed by, for example, an induction heater, and cooling can be performed using 5% H 2 —N 2 gas or the like. When performing heating / cooling, it is preferable to avoid changing the atmosphere in the heating furnace during cooling by separating the cooling chamber and the heating chamber and shutting them off with a valve.
また、雰囲気ガスの制御手段については特に限定はされないが、例えば、導入ガスのＨ２濃度をＮ２ガスとのガス流量比で制御し、また混合ガスの一部を水浴に導入してバブリングして導入することで雰囲気の露点と酸素分圧を制御することができる。 The control means for the atmospheric gas is not particularly limited. For example, the H 2 concentration of the introduced gas is controlled by the gas flow ratio with the N 2 gas, and a part of the mixed gas is introduced into the water bath and bubbled. It is possible to control the dew point and oxygen partial pressure of the atmosphere.
雰囲気ガスの切り替えは、導入ガスの切り替えにより行うことができる。一般に、ガス導入開始してから鋼板近傍の雰囲気が変化するまでには一定の時間が必要であると思われるが、あらかじめ炉内温度に加熱したガスを鋼板に直接吹き付けることにより鋼板近傍の雰囲気の置換は数秒で行われているものと推定される。 The atmospheric gas can be switched by switching the introduced gas. In general, it seems that a certain amount of time is required from the start of gas introduction until the atmosphere in the vicinity of the steel sheet changes, but by directly blowing the gas heated to the furnace temperature in advance to the steel sheet, It is estimated that the replacement is performed in a few seconds.
なお、ｐＯ２（酸素分圧）は、水蒸気分圧、水素分圧と式３：
ｐＯ２＝（ｐＨ２Ｏ／ｐＨ２）＾×ｅｘｐ（−ΔＧ／ＲＴ）
［式中、ΔＧ：水素の酸化反応のＧｉｂｂｓ自由エネルギー、Ｒ：気体定数、Ｔ：温度（Ｋ）を示す］
の関係にある。また水蒸気分圧と露点は下記Ａｕｇｕｓｔらの式：
ｅ（Ｔ）＝６．１０７８＊１０＾（７．５Ｔ／（Ｔ＋２３７．３））
［式中、Ｔ：温度（℃）を示す］
の関係にあることが知られており、これらの関係式を用いて、露点と水素濃度を制御することによって、酸素分圧を制御することができる。
In addition, pO 2 (oxygen partial pressure) is the partial pressure of water vapor and hydrogen, and Equation 3:
pO 2 = (pH 2 O / pH 2 ) ^ × exp (−ΔG / RT)
[In the formula, ΔG: Gibbs free energy of oxidation reaction of hydrogen, R: gas constant, T: temperature (K)]
Are in a relationship. The water vapor partial pressure and dew point are calculated by the following August et al. Formula:
e (T) = 6.1078 * 10 ^ (7.5T / (T + 237.3))
[In the formula, T represents temperature (° C.)]
The oxygen partial pressure can be controlled by controlling the dew point and the hydrogen concentration using these relational expressions.
〔めっき処理〕
上述の焼鈍処理後の溶融亜鉛めっき工程または合金化溶融亜鉛めっき工程については、特に限定されず、通常の条件・手段で行うことができる。例えば、過時効工程の保持温度がめっき浴温度（例えば４２０〜４８０℃）より高い場合には、適切な冷却速度（例えば、１．０〜３０℃／秒の平均冷却速度等）でめっき浴温度まで冷却して溶融亜鉛めっきを施す。また、過時効工程の保持温度がめっき浴温度より低い場合には、適宜、めっき浴温度まで加熱して溶融亜鉛めっきを施す。その後、室温まで冷却する。
[Plating treatment]
The hot dip galvanizing step or the galvannealed hot dip galvanizing step after the annealing treatment described above is not particularly limited and can be performed under normal conditions and means. For example, when the holding temperature of the overaging process is higher than the plating bath temperature (for example, 420 to 480 ° C.), the plating bath temperature is set at an appropriate cooling rate (for example, an average cooling rate of 1.0 to 30 ° C./second). Cool down to hot dip galvanizing. Further, when the holding temperature in the overaging process is lower than the plating bath temperature, the hot dip galvanization is performed by appropriately heating to the plating bath temperature. Then, it cools to room temperature.
溶融亜鉛めっきは、溶融亜鉛めっき浴（温度４２０〜４８０℃程度）に１〜１０秒程度浸漬することによって行われる。 Hot dip galvanization is performed by immersing in a hot dip galvanizing bath (temperature of about 420 to 480 ° C.) for about 1 to 10 seconds.
また合金化を行う場合は、前記溶融亜鉛めっきの後５００〜７５０℃程度の温度まで加熱後、２０秒程度合金化を行い、室温まで冷却することが好ましい。 In the case of alloying, it is preferable that the alloy is alloyed for about 20 seconds after being heated to a temperature of about 500 to 750 ° C. after the hot dip galvanizing and then cooled to room temperature.
本実施形態では、上記焼鈍処理後、そのまま連続的に溶融めっき浴に浸漬する連続焼鈍めっきラインでめっき処理を行う。なお、その際は、板形状の鋼板を用いてもよいし、鋼帯（コイル）形状の鋼板を用いた連続焼鈍めっきラインでも同様の処理が可能である。 In the present embodiment, after the annealing treatment, the plating treatment is performed in a continuous annealing plating line that is continuously immersed in a hot dipping bath as it is. In this case, a plate-shaped steel plate may be used, or the same treatment is possible in a continuous annealing plating line using a steel strip (coil) -shaped steel plate.
本実施形態の鋼板製造方法において、上記焼鈍工程および上記めっき工程以外の工程については特に限定はされず、通常の工程（鋼の溶製から冷間圧延工程まで）を必要に応じて行うことができる。 In the steel plate manufacturing method of the present embodiment, the steps other than the annealing step and the plating step are not particularly limited, and a normal step (from steel melting to cold rolling step) may be performed as necessary. it can.
例えば、上記焼鈍工程の前工程としては、後述するような化学成分を有する鋼を熱間圧延し、その後、酸洗工程を経て、冷間圧延して焼鈍用の鋼板とする工程が挙げられる。 For example, the pre-process of the annealing process includes a process of hot-rolling steel having chemical components as described later, followed by a pickling process and cold-rolling to obtain a steel sheet for annealing.
本実施形態の熱間圧延工程、冷間圧延工程、および酸洗工程については特に限定はなく、通常の鋼板の製造方法において行われる条件を採用することができる。
具体的には、例えば、熱間圧延は、加熱温度１１００℃〜１３００℃程度、仕上げ圧延温度、８００℃〜９００℃程度に制御することが好ましい。また、熱間圧延後の巻取温度を５００〜７５０℃程度に制御することが好ましい。
There is no particular limitation on the hot rolling process, the cold rolling process, and the pickling process of the present embodiment, and conditions performed in a normal steel sheet manufacturing method can be employed.
Specifically, for example, the hot rolling is preferably controlled to a heating temperature of about 1100 ° C to 1300 ° C, a finish rolling temperature, and about 800 ° C to 900 ° C. Moreover, it is preferable to control the coiling temperature after hot rolling to about 500-750 degreeC.
また、冷間圧延を行う場合、例えば、圧下率２０％〜５０％という条件とすることができる。 Moreover, when performing cold rolling, it can be set as the conditions of 20%-50% of reduction rate, for example.
さらに、酸洗工程を行う場合、例えば、酸洗液としては、塩酸、硫酸、硝酸などを使用することができる。酸洗条件は、熱間圧延で生じた酸化スケールを除去できる範囲であれば特に限定されない。 次に、本実施形態の鋼板の鋼成分組成について説明する。 Furthermore, when performing a pickling process, hydrochloric acid, a sulfuric acid, nitric acid etc. can be used as a pickling liquid, for example. The pickling conditions are not particularly limited as long as the oxide scale generated by hot rolling can be removed. Next, the steel component composition of the steel plate of this embodiment is demonstrated.
（Ｓｉ：０．３％以上、２．７％以下）
本実施形態の製造方法は、Ｓｉを含む加工性に優れる鋼板を製造するための方法であるため、本実施形態の鋼成分はＳｉを必須として含んでいる。ただし、本実施形態の製造方法を、Ｓｉを含有していない、あるいは、Ｓ含有量が０．３％未満である鋼板に適用しても何ら問題はない。
(Si: 0.3% or more, 2.7% or less)
Since the manufacturing method of this embodiment is a method for manufacturing the steel plate which is excellent in workability containing Si, the steel component of this embodiment contains Si as essential. However, there is no problem even if the manufacturing method of the present embodiment is applied to a steel sheet that does not contain Si or has an S content of less than 0.3%.
Ｓｉは、加工性、すなわち、鋼板のプレス成形性を確保するために強度、伸びバランスを向上させる成分であり、０．３％以上添加する。好ましくは０．９％以上、より好ましくは１．２％以上添加する。さらに、加工性に非常に優れる鋼板を所望の場合は２．１％以上添加することが望ましい。ただし、添加しすぎると靭性が劣化するため、上限を２．７％とする。好ましくは２．４％以下、より好ましく２．２％以下である。またＳｉは、鋼板の硬質化に寄与する置換型固溶体強化元素でもある。 Si is a component that improves strength and elongation balance in order to ensure workability, that is, press formability of a steel sheet, and is added in an amount of 0.3% or more. Preferably it is 0.9% or more, more preferably 1.2% or more. Furthermore, it is desirable to add 2.1% or more when a steel sheet having excellent workability is desired. However, since the toughness deteriorates if added too much, the upper limit is made 2.7%. Preferably it is 2.4% or less, More preferably, it is 2.2% or less. Si is also a substitutional solid solution strengthening element that contributes to hardening of the steel sheet.
本実施形態の製造方法の対象となる高強度鋼板の鋼成分における上記Ｓｉ以外の化学成分組成は、特に制約されず、鋼板に求める特性（特に、自動車ボディ用として求められる特性等）に応じて適宜調整することができる。例えば、強度や加工性等の鋼板としての基本的な特性を発揮させるために、以下のような成分を含んでいてもよい。 The chemical component composition other than Si in the steel component of the high-strength steel sheet that is the target of the manufacturing method of the present embodiment is not particularly limited, and depends on characteristics required for the steel sheet (particularly characteristics required for an automobile body). It can be adjusted appropriately. For example, the following components may be included in order to exhibit basic characteristics as a steel sheet such as strength and workability.
〔Ｃ：０．０８〜０．２５％〕
Ｃは、鋼板の強度確保に有効な元素であるため、０．０８％以上含有させることが好ましい。より好ましくは０．１％以上である。しかしＣ含有量が過剰になると、強度が高まり過ぎて遅れ破壊性が悪化するおそれがあるため、０．２５％以下とすることが好ましい。より好ましくは０．２１％以下である。
[C: 0.08 to 0.25%]
Since C is an element effective for ensuring the strength of the steel sheet, it is preferably contained in an amount of 0.08% or more. More preferably, it is 0.1% or more. However, if the C content is excessive, the strength is excessively increased and the delayed fracture property may be deteriorated. Therefore, the C content is preferably 0.25% or less. More preferably, it is 0.21% or less.
〔Ｍｎ：１．０〜３．０％〕
Ｍｎは、鋼板の強度確保に有効な元素であり、１．０％以上含有させることが好ましい。好ましくは１．５％以上、より好ましくは２．０％以上含有させることが望ましい。一方、Ｍｎを多量に含有させると、偏析が顕著になり加工性が低下するおそれがあり、更には、溶接性も劣化し易くなる。よって上限を３．５％とすることが好ましい。好ましい上限は３．０％であり、より好ましくは２．５％である。
[Mn: 1.0 to 3.0%]
Mn is an element effective for ensuring the strength of the steel sheet, and is preferably contained at 1.0% or more. Preferably it is 1.5% or more, more preferably 2.0% or more. On the other hand, when Mn is contained in a large amount, segregation becomes prominent and workability may be lowered, and weldability is also likely to deteriorate. Therefore, the upper limit is preferably set to 3.5%. A preferable upper limit is 3.0%, more preferably 2.5%.
また、上記以外にも、さらに質量％で、Ａｌ：０％超、０．２％以下、Ｃｒ：０％超、２％以下、Ｎｉ：０％超、０．５％以下、Ｃｕ：０％超、０．５％以下、Ｔｉ：０％超、０．３％以下、Ｍｏ：０％超、１％以下、およびＢ：０％超、０．０２％以下よりなる群から選ばれる少なくとも１種を含有してもよい。 In addition to the above, in addition to mass%, Al: more than 0%, 0.2% or less, Cr: more than 0%, 2% or less, Ni: more than 0%, 0.5% or less, Cu: 0% At least 1 selected from the group consisting of more than 0.5% or less, Ti: more than 0%, 0.3% or less, Mo: more than 0%, 1% or less, and B: more than 0%, 0.02% or less. It may contain seeds.
なお、本実施形態の鋼において、上述したような基本的な成分以外の残部は鉄および不可避不純物（例えば、Ｐ、Ｓ、Ｂ，Ｎ等）であるが、不可避不純物として、原料、資材、製造設備等の状況によって持ち込まれる元素の混入も許容される。 In the steel of the present embodiment, the balance other than the basic components as described above is iron and unavoidable impurities (for example, P, S, B, N, etc.). The inclusion of elements brought in depending on the situation of equipment etc. is allowed.
このような成分を有する鋼を用いて本実施形態の製造方法により得られる鋼板は、加工性に優れ、かつ、めっき性にも優れるため、自動車用部品等の幅広い用途に好適に使用できる。 A steel sheet obtained by the production method of the present embodiment using steel having such a component is excellent in workability and excellent in plating properties, and therefore can be suitably used for a wide range of applications such as automotive parts.
以上説明したように、本発明の一局面に係る鋼板の製造方法は、Ｓｉを含有する素地鋼板に、焼鈍処理およびめっき処理を連続的に行うことにより溶融亜鉛めっき鋼板又は合金化溶融亜鉛めっき鋼板を製造する方法であって、
前記焼鈍処理が、
鋼板を７００℃〜９５０℃の温度域で４０秒〜３６０秒間滞在させ、さらに雰囲気が７００℃以上では水素を３体積％以上含有し、かつ、初めて７００℃以上に達してから最初の４０秒間以上（最大で均熱工程の最後まで）において、ｐＯ２を酸素分圧（Ｐａ）、｛Ｓｉ｝をＳｉ含有量（質量％）とした場合に、式１：
（｛Ｓｉ｝）＾２×７．３×１０＾（−２２）≦ｐＯ２
を満たすガス雰囲気となるように制御する均熱工程と、
前記均熱工程の後に、鋼板を３００℃〜６７０℃の温度域で９０秒〜６００秒間滞在させ、雰囲気が前記均熱工程以降であって６７０℃以下の範囲において水素を３体積％以上含有し、露点が、ＤＰを露点（℃）、Ｔを保持温度（℃）とした場合に、下記式２：
ＤＰ≦０．０００７３×Ｔ２−０．４１×Ｔ＋３８
を満たすガス雰囲気となるように制御する過時効工程とを含むことを特徴とする。
As described above, the method for producing a steel sheet according to one aspect of the present invention includes a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet by continuously performing annealing and plating on a base steel sheet containing Si. A method of manufacturing
The annealing treatment is
The steel plate is allowed to stay in a temperature range of 700 ° C. to 950 ° C. for 40 seconds to 360 seconds. Further, when the atmosphere is 700 ° C. or higher, it contains 3% by volume or more of hydrogen. (Up to the end of the soaking step at the maximum), when pO 2 is oxygen partial pressure (Pa) and {Si} is Si content (mass%), formula 1:
({Si}) ^ 2 × 7.3 × 10 ^ (− 22) ≦ pO 2
A soaking process that controls the gas atmosphere to satisfy
After the soaking step, the steel plate is allowed to stay in a temperature range of 300 ° C. to 670 ° C. for 90 seconds to 600 seconds, and the atmosphere is after the soaking step and contains 3% by volume or more of hydrogen in a range of 670 ° C. or less. When the dew point is DP as the dew point (° C.) and T as the holding temperature (° C.), the following formula 2:
DP ≦ 0.00073 × T 2 −0.41 × T + 38
And an overaging process for controlling the gas atmosphere to satisfy the above condition.
このような構成により、鋼板の成形性を向上でき、さらに、不めっきの発生も抑制することができる。 With such a configuration, the formability of the steel sheet can be improved and the occurrence of non-plating can be suppressed.
また、前記製造方法において、前記素地鋼板のＳｉ含有量が０．３〜２．７％（質量％の意味。以下、特に言及しない限り、成分組成において同じ）であることが好ましい。それにより、より加工性に優れた鋼板を製造することができると考えられる。 Moreover, in the said manufacturing method, it is preferable that Si content of the said base steel plate is 0.3-2.7% (meaning of the mass%. Hereinafter, unless it mentions especially, it is the same in a component composition). Thereby, it is thought that the steel plate excellent in workability can be manufactured.
さらに、前記製造方法において、前記均熱工程の後であって、前記過時効工程の前に、冷却工程をさらに含むことが好ましい。それにより、鋼板の強度と加工性のバランスがさらに向上するという利点がある。 Furthermore, the manufacturing method preferably further includes a cooling step after the soaking step and before the overaging step. Thereby, there exists an advantage that the balance of the intensity | strength and workability of a steel plate further improves.
本発明を、実施例を用いてさらに具体的に説明するが、本発明はこれらの実施例により何ら限定されない。 The present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
〔鋼板サンプルの製造〕
（溶製・圧延）
素地鋼板を以下の手順で製造した。すなわち、下記の表１に示す化学成分組成を有し、残部が鉄および不可避不純物からなる鋼Ａ〜Ｆを溶製し、スラブとした。表１において「−」は検出限界以下を意味する。
[Manufacture of steel plate samples]
(Melting / Rolling)
A base steel plate was produced by the following procedure. That is, steels A to F having the chemical composition shown in Table 1 below and the balance being iron and inevitable impurities were melted to form slabs. In Table 1, “-” means below the detection limit.
得られたスラブを熱間圧延して板厚が３．２ｍｍの熱延鋼板を製造した。得られた熱延鋼板を塩酸酸洗により黒皮除去、冷間圧延し、板厚が１．４ｍｍの冷延鋼板を製造した。 The obtained slab was hot-rolled to produce a hot-rolled steel sheet having a thickness of 3.2 mm. The obtained hot-rolled steel sheet was subjected to removal of black skin by hydrochloric acid pickling and cold-rolled to produce a cold-rolled steel sheet having a thickness of 1.4 mm.
（焼鈍・めっき又は合金化めっき）
得られた冷延鋼板に対して、表２および３に示すように制御した雰囲気で焼鈍（均熱・冷却・過時効）を行い、そのまま連続的に溶融めっき浴に浸漬することができる実験装置を用いて、焼鈍、めっき実験を行った。
(Annealing / plating or alloying plating)
An experimental apparatus that can anneal the obtained cold-rolled steel sheet in a controlled atmosphere as shown in Tables 2 and 3 (soaking / cooling / overaging) and continuously immerse it directly in a hot dipping bath. Were used for annealing and plating experiments.
加熱パターンは図１に示すパターンである。表２および３において、時間ｔ１〜ｔ３は、それぞれ図１に示すように、ｔ１：均熱工程における７００℃以上の温度帯における滞在時間、ｔ２：均熱工程における雰囲気制御時間、ｔ３：過時効工程における３００〜６５０℃の温度帯での滞在時間を示す。また、温度Ｔ１〜Ｔ３は、同じく図１に示すように、Ｔ１：均熱工程の保持温度、Ｔ２：均熱工程から冷却工程を行った後の冷却終了温度、Ｔ３：過時効工程の保持温度を示す。 The heating pattern is the pattern shown in FIG. In Tables 2 and 3, as shown in FIG. 1, each of the times t 1 to t 3 is t 1 : residence time in a temperature range of 700 ° C. or higher in the soaking process, t 2 : atmosphere control time in the soaking process, t 3: shows the time spent in the temperature range of 300 to 650 ° C. in overaging process. Also, as shown in FIG. 1, temperatures T 1 to T 3 are as follows: T 1 : holding temperature of soaking process, T 2 : cooling end temperature after performing cooling process from soaking process, T 3 : excess Indicates the holding temperature of the aging process.
なお、表２および３において、均熱工程における項目の式１が「○」とは、温度が７００℃以上に達してから４０秒間以上にわたり、式１：
（｛Ｓｉ｝）＾２×７．３×１０＾（−２２）≦ｐＯ２
を満たしている場合をさし、「×」は満たしていない場合をさす。また、過時効工程における項目の式２が「○」とは、式２：
ＤＰ≦０．０００７３×Ｔ３ ２−０．４１×Ｔ３＋３８
を満たしている場合をさし、「×」は満たしていない場合をさす。
In Tables 2 and 3, Equation 1 of the item in the soaking step is “◯”, which means that the equation 1:
({Si}) ^ 2 × 7.3 × 10 ^ (− 22) ≦ pO 2
The case where “x” is satisfied, and the case where “x” is not satisfied. In addition, when the formula 2 of the item in the overaging process is “◯”, the formula 2:
DP ≦ 0.00073 × T 3 2 −0.41 × T 3 +38
The case where “x” is satisfied, and the case where “x” is not satisfied.
各工程における加熱はインダクションヒーターで行い、昇温速度は１０℃/秒とした。一方、冷却は５％Ｈ２−Ｎ２ガスで行った。また、冷却室と加熱室とを分け、その間をバルブで遮断することで冷却中に加熱炉内の雰囲気が変化することを避けた。 Heating in each step was performed with an induction heater, and the rate of temperature increase was 10 ° C./second. On the other hand, cooling was performed with 5% H 2 —N 2 gas. Moreover, the cooling chamber and the heating chamber were separated, and the space between them was shut off with a valve to avoid changing the atmosphere in the heating furnace during cooling.
また、雰囲気ガスは流量３３．６Ｌ／分でパージ（排気）することで行った。導入ガスのＨ２濃度をＮ２ガスとのガス流量比で制御し、また混合ガスの一部を水浴に導入してバブリングして導入することで雰囲気の露点と酸素分圧を制御した。なお、酸素分圧については、露点と水素濃度を制御することによって、制御した。 The atmosphere gas was purged (exhausted) at a flow rate of 33.6 L / min. The dew point and oxygen partial pressure of the atmosphere were controlled by controlling the H 2 concentration of the introduced gas by the gas flow ratio with the N 2 gas and introducing a part of the mixed gas by bubbling and introducing it. The oxygen partial pressure was controlled by controlling the dew point and the hydrogen concentration.
雰囲気ガスの切り替えは、導入ガスの切り替えにより行った。 The atmosphere gas was switched by switching the introduced gas.
次に、めっき浴（４６０℃）に浸漬してめっき処理を行った。めっきの付着量はガスワイピングで制御した。一部のサンプルはめっき後、合金化炉で、５５０℃で２０秒間の合金化処理を行った。 Next, it was immersed in a plating bath (460 ° C.) for plating treatment. The amount of plating was controlled by gas wiping. Some samples were subjected to alloying treatment at 550 ° C. for 20 seconds in an alloying furnace after plating.
めっき浴は、合金化する場合（ＧＡ）は０．１％Ａｌ−Ｚｎ浴、合金化しない場合（ＧＩ）は０．２％Ａｌ−Ｚｎ浴とした。 The plating bath was a 0.1% Al—Zn bath when alloying (GA) and a 0.2% Al—Zn bath when not alloying (GI).
（焼鈍後分析）
上記で行った各実験Ｎｏ．１〜５３に対し、焼鈍工程終了後にめっき処理をせず、そのまま冷却した焼鈍サンプルを作製して表面分析を行い、めっき浸漬前の鋼板表面にＳｉＯ２が生成しているか否かを評価した。具体的には、焼鈍後、めっき処理をせずにそのまま冷却して取り出したサンプルについて、ＦＴ−ＩＲ（赤外線吸収分光装置 日本分光株式会社製 ＦＴ／ＩＲ−４１０）を用いてＳｉＯ２の吸収ピークの有無を確認した。吸収が見られたもの、つまり焼鈍によりＳｉが生成したものを「×」、吸収が見られないものを「○」とした。
(Analysis after annealing)
Each experiment No. performed above was carried out. With respect to 1 to 53, an annealing sample that was cooled as it was without performing plating treatment after the annealing process was completed and subjected to surface analysis, whether or not SiO 2 was generated on the steel sheet surface before plating immersion was evaluated. Specifically, after annealing, the sample that was cooled and taken out without being subjected to plating treatment was subjected to SiO 2 absorption peak using FT-IR (FT / IR-410 manufactured by JASCO Corporation). The presence or absence was confirmed. The case where absorption was observed, that is, the case where Si was generated by annealing was indicated as “x”, and the case where absorption was not observed was indicated as “◯”.
（不めっきの評価）
各実験条件で作製したサンプルの不めっきの面積率を、以下のように評価とした。
(Evaluation of non-plating)
The unplated area ratio of the samples produced under each experimental condition was evaluated as follows.
サンプルのめっき浴に浸漬された領域（７０ｍｍ×１００ｍｍ）を、図２に示すように、５ｍｍ角の升目で区切り、各升目内のめっきが付いていない面積率が５０％以下である升の個数を目視で数えた。そして、数えた個数の、全升目の個数（２８０升）に対する割合によって、不めっき面積率とした。 As shown in FIG. 2, the area (70 mm × 100 mm) immersed in the plating bath of the sample is divided by 5 mm square meshes, and the number of ridges where the area ratio without plating in each square is 50% or less Were counted visually. And it was set as the non-plating area ratio by the ratio with respect to the number (280 square meters) of all the squares of the counted number.
そして、不めっき面積率３％以上を×（不合格）、３％未満を○（良好）と評価した。 And 3% or more of non-plating area ratio evaluated x (failure) and less than 3% as (circle) (good).
結果を表２および表３に示す。 The results are shown in Table 2 and Table 3.
（考察）
本発明の範囲を満たす条件で製造を行った実施例においては、いずれも、めっき浸漬前の鋼板表面にＳｉＯ２が生成しておらず、不めっきの評価も良好（不めっき面積率が３％未満）であった。
(Discussion)
In all the examples manufactured under the conditions satisfying the scope of the present invention, no SiO 2 was formed on the steel plate surface before plating immersion, and the evaluation of non-plating was good (non-plating area ratio was 3%). Less).
これに対し、実験Ｎｏ．１〜２、４、２４〜２５、３０〜３１、３６〜３７、４２および４８では、過時効工程における露点が高すぎて式２を満たさなかったため、不めっきが発生してしまった。 In contrast, Experiment No. In 1-2, 4, 24-25, 30-31, 36-37, 42 and 48, since the dew point in the overaging process was too high to satisfy Equation 2, non-plating occurred.
また、実験Ｎｏ．１３〜１５では、均熱工程における雰囲気制御時間（上記ｔ２）が不足し、７００℃に至ってから最初の４０秒間以上にわたり式１を満たしていなかったため、焼鈍後に鋼板表面にＳｉＯ２が生成し、不めっきが発生した。 In addition, Experiment No. In Nos. 13 to 15, the atmosphere control time in the soaking process (t 2 above) was insufficient, and since Formula 1 was not satisfied over the first 40 seconds after reaching 700 ° C., SiO 2 was generated on the steel sheet surface after annealing. Unplating occurred.
実験Ｎｏ．２３、２９、３５および４１では、均熱工程における露点が低くなり、その結果、酸素分圧が下がり、７００℃に至ってから最初の４０秒間以上にわたり上記式１を満たしていなかったため、焼鈍後に鋼板表面にＳｉＯ２が生成し、不めっきが発生した。 Experiment No. 23, 29, 35 and 41, the dew point in the soaking process was lowered, and as a result, the oxygen partial pressure was lowered, and since it did not satisfy the above formula 1 for the first 40 seconds or more after reaching 700 ° C., the steel sheet was annealed. SiO 2 was generated on the surface and non-plating occurred.
実験Ｎｏ．２６、３２および３８では、均熱工程における露点が低くなり、その結果、酸素分圧が下がって上記式１の条件を満たさず、さらに、過時効工程における露点が高すぎて上記式２を満たさなかったため、焼鈍後に鋼板表面にＳｉＯ２が生成し、不めっきが発生した。 Experiment No. 26, 32 and 38, the dew point in the soaking process is lowered, and as a result, the partial pressure of oxygen is lowered and does not satisfy the condition of the above formula 1, and the dew point in the overaging process is too high to satisfy the above formula 2. because there was no, SiO 2 is produced on the surface of the steel sheet after annealing, non-plating occurs.
以上より、本発明の製造方法によれば、Ｓｉを含有する鋼板においても不めっきを発生しにくいことが確かめられた。特に、過時効工程を含む場合には、７００℃以上の焼鈍処理における雰囲気を制御することによって、焼鈍後の鋼板表面にＳｉＯ２が生成することを抑制するだけでは不めっきが回避できないことが明らかとなった。本発明のように、さらに過時効工程における酸素分圧や雰囲気を制御することにより、はじめて不めっきを抑制できることが示された。
From the above, according to the production method of the present invention, it has been confirmed that non-plating hardly occurs even in a steel sheet containing Si. In particular, when an overaging process is included, it is clear that non-plating cannot be avoided simply by suppressing the formation of SiO 2 on the surface of the steel sheet after annealing by controlling the atmosphere in the annealing process at 700 ° C. or higher. It became. It was shown that non-plating can be suppressed only by controlling the oxygen partial pressure and atmosphere in the overaging process as in the present invention.
Claims (3)
前記焼鈍処理が、
鋼板を７００℃〜９５０℃の温度域で４０秒〜３６０秒間滞在させ、さらに雰囲気が７００℃以上では水素を３体積％以上含有し、かつ、初めて７００℃以上に達してから最初の４０秒間以上（最大で均熱工程の最後まで）において、ｐＯ２を酸素分圧（Ｐａ）、｛Ｓｉ｝をＳｉ含有量（質量％）とした場合に、式１：
（｛Ｓｉ｝）＾２×７．３×１０＾（−２２）≦ｐＯ２
を満たすガス雰囲気となるように制御する均熱工程と、
前記均熱工程の後に、鋼板を３００℃〜６７０℃の温度域で９０秒〜６００秒間滞在させ、雰囲気が前記均熱工程以降であって６７０℃以下の範囲において水素を３体積％以上含有し、露点が、ＤＰを露点（℃）、Ｔを保持温度（℃）とした場合に、下記式２：
ＤＰ≦０．０００７３×Ｔ２−０．４１×Ｔ＋３８
を満たすガス雰囲気となるように制御する過時効工程とを含む、
前記めっき鋼板の製造方法。 A method for producing a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet by continuously performing annealing and plating on a base steel sheet containing Si,
The annealing treatment is
The steel plate is allowed to stay in a temperature range of 700 ° C. to 950 ° C. for 40 seconds to 360 seconds. Further, when the atmosphere is 700 ° C. or higher, it contains 3% by volume or more of hydrogen. (Up to the end of the soaking step at the maximum), when pO 2 is oxygen partial pressure (Pa) and {Si} is Si content (mass%), formula 1:
({Si}) ^ 2 × 7.3 × 10 ^ (− 22) ≦ pO 2
A soaking process that controls the gas atmosphere to satisfy
After the soaking step, the steel plate is allowed to stay in a temperature range of 300 ° C. to 670 ° C. for 90 seconds to 600 seconds, and the atmosphere is after the soaking step and contains 3% by volume or more of hydrogen in a range of 670 ° C. or less. When the dew point is DP as the dew point (° C.) and T as the holding temperature (° C.), the following formula 2:
DP ≦ 0.00073 × T 2 −0.41 × T + 38
Including an overaging process for controlling the gas atmosphere to satisfy
The manufacturing method of the said plated steel plate.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2016177281A JP2018044183A (en) | 2016-09-12 | 2016-09-12 | Production metho of plated steel sheet |
| PCT/JP2017/032201 WO2018047891A1 (en) | 2016-09-12 | 2017-09-07 | Method for producing plated steel sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2016177281A JP2018044183A (en) | 2016-09-12 | 2016-09-12 | Production metho of plated steel sheet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2018044183A true JP2018044183A (en) | 2018-03-22 |
Family
ID=61562176
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2016177281A Pending JP2018044183A (en) | 2016-09-12 | 2016-09-12 | Production metho of plated steel sheet |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP2018044183A (en) |
| WO (1) | WO2018047891A1 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5799819B2 (en) * | 2012-01-13 | 2015-10-28 | 新日鐵住金株式会社 | Method for producing hot-dip galvanized steel sheet with excellent plating wettability and pick-up resistance |
| IN2015DN03981A (en) * | 2012-12-04 | 2015-10-02 | Jfe Steel Corp |
-
2016
- 2016-09-12 JP JP2016177281A patent/JP2018044183A/en active Pending
-
2017
- 2017-09-07 WO PCT/JP2017/032201 patent/WO2018047891A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| WO2018047891A1 (en) | 2018-03-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5532188B2 (en) | Manufacturing method of high-strength steel sheet with excellent workability | |
| JP5206705B2 (en) | High-strength hot-dip galvanized steel sheet and manufacturing method thereof | |
| JP4804996B2 (en) | Method for producing alloyed hot-dip galvanized steel sheet with good workability, powdering property and slidability | |
| JP5799819B2 (en) | Method for producing hot-dip galvanized steel sheet with excellent plating wettability and pick-up resistance | |
| KR101900963B1 (en) | Method of producing an austenitic steel | |
| JP2020147852A (en) | Method for producing coated steel sheet having improved strength, ductility and formability | |
| JPWO2016038801A1 (en) | Manufacturing method and manufacturing equipment for high strength hot dip galvanized steel sheet | |
| JP5552863B2 (en) | High-strength hot-dip galvanized steel sheet and manufacturing method thereof | |
| JP2014019905A (en) | Galvannealed steel sheet and manufacturing method therefor | |
| JP7241283B2 (en) | Aluminum-iron plated steel sheet for hot press with excellent corrosion resistance and weldability and its manufacturing method | |
| JP5552859B2 (en) | High-strength hot-dip galvanized steel sheet and manufacturing method thereof | |
| JP6191810B1 (en) | Steel plate manufacturing method | |
| JP5593771B2 (en) | Method for producing high-strength hot-dip galvanized steel sheet | |
| JP2006283071A (en) | Method for producing galvannealed high strength steel sheet excellent in workability | |
| JP2010111891A (en) | Cold rolled steel sheet, surface treated steel sheet, and method for producing the same | |
| JP2013122074A (en) | High-strength steel sheet and method of producing the same | |
| JP5834870B2 (en) | High strength steel plate and manufacturing method thereof | |
| JP5212056B2 (en) | Method for producing galvannealed steel sheet | |
| JP7167343B2 (en) | Aluminum plated steel sheet for hot press with excellent hydrogen delayed fracture characteristics and spot weldability, and method for producing the same | |
| JP2007291445A (en) | Method for producing high tension hot-dip galvanized hot-rolled steel sheet excellent in wettability and bulging property | |
| JP4975406B2 (en) | High-strength galvannealed steel sheet and method for producing the same | |
| WO2018047891A1 (en) | Method for producing plated steel sheet | |
| JP2010255112A (en) | High strength hot dip galvanized steel sheet and method for producing the same | |
| JP6518949B2 (en) | Method of manufacturing hot-dip galvanized steel sheet and hot-dip galvanized steel sheet | |
| WO2022191008A1 (en) | Method for manufacturing hot-dip galvanized steel sheet and method for manufacturing alloyed hot-dip galvanized steel sheet |