JPH0230720A - Method for heating steel sheet - Google Patents
Method for heating steel sheetInfo
- Publication number
- JPH0230720A JPH0230720A JP17785988A JP17785988A JPH0230720A JP H0230720 A JPH0230720 A JP H0230720A JP 17785988 A JP17785988 A JP 17785988A JP 17785988 A JP17785988 A JP 17785988A JP H0230720 A JPH0230720 A JP H0230720A
- Authority
- JP
- Japan
- Prior art keywords
- zone
- steel plate
- steel sheet
- combustion
- furnace
- 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 71
- 239000010959 steel Substances 0.000 title claims abstract description 71
- 238000010438 heat treatment Methods 0.000 title claims abstract description 43
- 238000000034 method Methods 0.000 title claims description 10
- 238000002485 combustion reaction Methods 0.000 claims abstract description 27
- 230000001603 reducing effect Effects 0.000 claims abstract description 14
- 239000000567 combustion gas Substances 0.000 claims abstract description 13
- 238000005246 galvanizing Methods 0.000 abstract description 5
- 238000000137 annealing Methods 0.000 abstract description 4
- 230000001590 oxidative effect Effects 0.000 abstract description 4
- 238000004140 cleaning Methods 0.000 abstract description 3
- 238000005192 partition Methods 0.000 abstract description 3
- 238000004519 manufacturing process Methods 0.000 abstract description 2
- 230000005855 radiation Effects 0.000 abstract description 2
- 238000010304 firing Methods 0.000 abstract 2
- 239000007789 gas Substances 0.000 description 18
- 230000003647 oxidation Effects 0.000 description 11
- 238000007254 oxidation reaction Methods 0.000 description 11
- 239000000446 fuel Substances 0.000 description 7
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 239000010731 rolling oil Substances 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 235000012149 noodles Nutrition 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000000284 resting effect Effects 0.000 description 1
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、連続溶融亜鉛めっき設備の一部を構成する無
酸化炉や連続焼鈍炉等の直火式加熱炉による鋼板の加熱
方法に関する。直火式加熱炉は、バーナを備えた複数個
の燃焼ゾーンを有しており、ここに鋼板を通過させ、未
燃分を含んだ還元性の燃焼ガスによって鋼板を還元性雰
囲気下で直接加熱するものである。DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method of heating a steel plate using a direct-fired heating furnace such as a non-oxidizing furnace or a continuous annealing furnace, which constitutes a part of continuous hot-dip galvanizing equipment. A direct-fired heating furnace has multiple combustion zones equipped with burners, through which the steel plate is passed, and the steel plate is directly heated in a reducing atmosphere by reducing combustion gas containing unburned components. It is something to do.
（従来の技術と課題）
従来、連続焼鈍溶融亜鉛めっき設備における無酸化炉は
、直火加熱により薄鋼板に種々の熱処理を施したり、鋼
板表面に付着した圧延油等を燃焼除去し、鋼板表面の清
浄化を行うために使用される。(Conventional technology and issues) Conventionally, non-oxidation furnaces used in continuous annealing hot-dip galvanizing equipment have been used to perform various heat treatments on thin steel plates by direct heating, burn off rolling oil etc. adhering to the steel plate surface, and remove the rolling oil etc. used for cleaning.
この際、鋼板表面が酸化するのを防止する必要があるた
め、加熱源であるバーナは、空気比を１未満（通常、０
．８５〜０．９６程度）として使用されている。ここに
空気比とは、（バーナに供給された空気量）／（バーナ
に供給された燃料を完全燃焼させるのに要する理論空気
ｆｆ１）の比をいい、空気比が１未満では、燃焼ガス中
にＣＯガスやＨ２ガスが未燃分として残留し、これが還
元作用を奏する。At this time, it is necessary to prevent the surface of the steel plate from oxidizing, so the burner, which is the heating source, has an air ratio of less than 1 (usually 0).
．． 85 to 0.96). The air ratio here refers to the ratio of (amount of air supplied to the burner)/(theoretical air ff1 required for complete combustion of the fuel supplied to the burner), and if the air ratio is less than 1, the amount of air in the combustion gas CO gas and H2 gas remain as unburned components, and this acts as a reducing agent.
そして、鋼板出口側の燃焼ゾーンは、鋼板入口側の燃焼
ゾーンよりも高い燃焼負荷で操業されるのが通例である
。鋼板が加熱炉から出たとき所期の高温が得られればよ
く、また燃料消費量を軽減することができるからである
。ここに、燃焼負荷とは、各燃焼ゾーンにおけるバーナ
の燃焼量をいい、供給燃料が多い程、また空気比が大き
い程大きい。The combustion zone on the steel plate outlet side is usually operated with a higher combustion load than the combustion zone on the steel plate inlet side. This is because it is sufficient to obtain the desired high temperature when the steel plate comes out of the heating furnace, and fuel consumption can be reduced. Here, the combustion load refers to the combustion amount of the burner in each combustion zone, and increases as the amount of supplied fuel increases and the air ratio increases.
しかしながら、空気比１未満とし、燃焼ガスを還元性ガ
スとして操業しても、鋼板表面の酸化膜が十分除去され
ないのが実情である。この原因は、バーナの燃焼性能、
複数バーナ間の燃料と空気のアンバランス等によって燃
焼ガス中に酸素が不可避的に混入し、これによって酸化
膜が生成するからと考えられる。However, even if the air ratio is less than 1 and the combustion gas is used as a reducing gas, the oxide film on the surface of the steel sheet is not sufficiently removed. The cause of this is the combustion performance of the burner,
It is thought that this is because oxygen is inevitably mixed into the combustion gas due to an imbalance between fuel and air between multiple burners, and this causes the formation of an oxide film.
このような酸化膜が存在すると、めっき不良の原因とな
るため、無酸化炉の後に還元炉を設け、酸化膜を加熱還
元し、鋼板表面の清浄化を行っている。尚、還元炉は、
通常、不活性ガスである窒素ガスと還元性ガスである水
素ガスとの混合ガスを炉内雰囲気ガスとして使用されて
いる。The presence of such an oxide film causes plating defects, so a reduction furnace is provided after the non-oxidation furnace to reduce the oxide film by heating and clean the surface of the steel plate. In addition, the reduction furnace is
Usually, a mixed gas of nitrogen gas, which is an inert gas, and hydrogen gas, which is a reducing gas, is used as the furnace atmosphere gas.
本発明はかかる問題点に鑑みなされたもので、直火式加
熱炉による鋼板の加熱に際し、鋼板の酸化を可及的に抑
制することができる加熱方法を提供することを目的とす
る。The present invention was made in view of such problems, and an object of the present invention is to provide a heating method that can suppress oxidation of a steel plate as much as possible when heating the steel plate using a direct-fired heating furnace.
尚、無酸化炉において発生した還元性ガス（ＩＩ２゜Ｃ
Ｏガス）および還元炉の還元性ガス（ｌ（２ガス）は、
燃焼ガスと共に、燃焼ゾーンの入口側前方に設けられた
対流予熱帯や輻射予熱帯を経て排気される。In addition, the reducing gas (II2°C) generated in the non-oxidizing furnace
O gas) and the reducing gas (l (2 gas) in the reduction furnace are:
Together with the combustion gas, it is exhausted through a convection pre-heating zone and a radiation pre-heating zone provided at the front of the inlet side of the combustion zone.
この際、還元性ガスは、省エネルギーおよび公害防止の
観点から、通常、補足空気を投入して輻射予熱帯に設け
たアフターバーン装置によって完全燃焼させる措置が採
られている。At this time, from the viewpoint of energy saving and pollution prevention, measures are normally taken to completely burn the reducing gas using an afterburn device provided in the radiant preheating zone by introducing supplementary air.
（課題を解決するための手段）
上記目的を達成するためになされた本発明の加熱方法は
、バーナを備えた複数個の燃焼ゾーンを有する加熱炉に
鋼板を通過させ、未燃分を含んだ還元性の燃焼ガスによ
って鋼板を直接加熱する方法において、鋼板入口側の前
段ゾーンを高負荷燃焼とし、少なくとも鋼板温度が４０
０℃から６００℃になるまでの間、鋼板を急速加熱する
ことを発明の構成とするものである。(Means for Solving the Problems) The heating method of the present invention, which was made to achieve the above object, involves passing a steel plate through a heating furnace equipped with a burner and having a plurality of combustion zones. In a method of directly heating a steel plate with reducing combustion gas, the front zone on the steel plate inlet side is subjected to high-load combustion, and the steel plate temperature is at least 40℃.
The structure of the invention is to rapidly heat a steel plate from 0°C to 600°C.
鋼板の酸化防止をより確実に行うには、鋼板出口側の後
段ゾーンの空気比を前段ゾーンより小さくすればよい。In order to more reliably prevent oxidation of the steel plate, the air ratio in the latter zone on the exit side of the steel plate may be made smaller than in the former zone.
（作 用）
鋼板入口側の前段ゾーンを高負荷燃焼とすることで、鋼
板が加熱炉に進入すると共に急速加熱を行うことができ
る。ここに、前段ゾーンとは、高負荷燃焼操業している
、鋼板入口側の−又は二基上の燃焼ゾーンをいう。(Function) By performing high-load combustion in the front zone on the steel plate inlet side, rapid heating can be performed as the steel plate enters the heating furnace. Here, the pre-stage zone refers to the combustion zone on the inlet side of the steel plate or two combustion zones above the steel plate inlet side where high-load combustion operation is performed.
鋼板に対する急速加熱は、少なくとも鋼板温度が４００
℃から６００℃になるまでの間、行われる。本発明者の
知見によると、鋼板は、４００″Ｃから６００’Ｃの間
で極めて酸化され易いからである。この間での加熱速度
が遅いと酸化量が著しく増大し、その後、還元雰囲気下
で操業している後段ゾーン（全燃焼ゾーンの内、前段ゾ
ーンを除く部分）に鋼板を移行させても、移行中に酸化
膜を十分除去することができなくなるからである。逆に
、４００℃から６００℃の間を急速加熱（望ましくはこ
の温度間を６秒以内で加熱）すると、空気比が１程度で
あっても、酸化量はそれほど増大せず、後段ゾーンを移
行中に酸化物は十分還元除去される。Rapid heating of a steel plate is performed until the steel plate temperature is at least 400℃.
It is carried out from ℃ to 600℃. According to the findings of the present inventor, steel plates are extremely easily oxidized between 400''C and 600'C.If the heating rate is slow during this period, the amount of oxidation increases significantly, and after that, under a reducing atmosphere, This is because even if the steel plate is transferred to the latter zone of operation (the part of the entire combustion zone excluding the first zone), the oxide film cannot be sufficiently removed during the transfer.On the contrary, from 400℃ When rapidly heated to 600°C (preferably within 6 seconds between these temperatures), the amount of oxidation does not increase significantly even if the air ratio is about 1, and the oxides are sufficiently absorbed during transfer to the latter zone. Reduced and removed.
因みに、第３図に示した加熱速度で加熱した軟鋼板（０
，０５ｗｔ％Ｃ）の各温度における生成した酸化膜厚を
第４図および第５図に示す。第４図は加熱速度が大きい
場合（第３図中Ａに該当）、第５図は加熱速度が小さい
場合（第３図中Ｂに該当）である。加熱速度の調整は、
一定温度（１４００’Ｃ）の燃焼ガス中に厚さの異なる
軟鋼板を挿入することにより行った。第３図中Ａは厚さ
１胴、Ｂは３胴の場合を示す。尚、バーナの空気比は０
．８とした。このとき、燃焼ガス中には（ＣＯ＋Ｈｚ）
ガスが８νｏ１％含まれていた。加熱中の鋼板は所定の
温度で炉から引き出し、窒素ガスで急速冷却し、鋼板表
面の酸化膜厚が測定された。Incidentally, a mild steel plate (0
, 05wt%C) are shown in FIGS. 4 and 5, respectively. 4 shows the case where the heating rate is high (corresponding to A in FIG. 3), and FIG. 5 shows the case when the heating rate is small (corresponds to B in FIG. 3). To adjust the heating rate,
This was done by inserting mild steel plates of different thicknesses into combustion gas at a constant temperature (1400'C). In FIG. 3, A shows the case where the thickness is one cylinder, and B shows the case where the thickness is three cylinders. Furthermore, the air ratio of the burner is 0.
．． It was set as 8. At this time, the combustion gas contains (CO+Hz)
It contained 8νo1% of gas. The heated steel plate was pulled out of the furnace at a predetermined temperature, rapidly cooled with nitrogen gas, and the oxide film thickness on the steel plate surface was measured.
鋼板を急速加熱した場合、第４図によると、鋼板温度が
ほぼ４００”Ｃ程度までは酸化が進行せず、４００〜６
００’Ｃで急速に酸化が進行し、６００″Ｃを越えると
還元が起こることが知られる。しかし、加熱速度が遅い
場合、第５図によると、６００’Ｃ以上の高温側での還
元が進捗していないことが知られる。According to Figure 4, when a steel plate is heated rapidly, oxidation does not proceed until the steel plate temperature reaches about 400"C.
It is known that oxidation proceeds rapidly at 00'C and reduction occurs at temperatures above 600'C. However, if the heating rate is slow, reduction occurs at high temperatures above 600'C, as shown in Figure 5. It is known that no progress has been made.
これは、４００〜６００℃における酸化領域での加熱時
間が長いと、酸化膜が厚くなり、また酸化膜が緻密化し
、酸化膜性状がより還元しにくくなるからと推察される
。This is presumed to be because when the heating time in the oxidized region at 400 to 600° C. is long, the oxide film becomes thick and dense, and the oxide film properties become more difficult to reduce.
前段ゾーンで４００℃から６００’Ｃの間、急速加熱さ
れた鋼板は、酸化量が可及的に抑えられているので、後
段ゾーンを移行する間に、未燃分を含んだ還元性燃焼ガ
スによって酸化膜が容易に還元され、鋼板表面の清浄化
が図られる。この際、鋼板の急速加熱を前段ゾーンで行
うため、後段ゾーンすなわち６００℃以上の還元領域を
長くとることができ、還元に有利である。Since the steel plate is rapidly heated between 400°C and 600'C in the first stage zone, the amount of oxidation is suppressed as much as possible, so reducing combustion gas containing unburned matter is transferred to the second stage zone. The oxide film is easily reduced and the surface of the steel plate is cleaned. At this time, since the steel plate is rapidly heated in the former zone, the latter zone, that is, the reduction region of 600° C. or higher, can be made long, which is advantageous for reduction.
また、後段ゾーンの空気比を前段ゾーンのそれより小さ
く（望ましくは、両者の差が０．１５以上となるように
小さく）することによって、後段ゾーンの還元作用を強
力にすることができ、鋼板表面の酸化膜の確実な除去を
行うことができる。In addition, by making the air ratio in the rear zone smaller than that in the front zone (preferably so that the difference between the two is smaller than 0.15), the reduction effect in the rear zone can be strengthened, and the steel plate The oxide film on the surface can be reliably removed.
（実施例）
第１図は本発明を実施するための直火式加熱炉の一例で
あり、鋼板入口側から出口側（鋼板移送方向、図中矢印
方向）に向って、対流予熱帯２、輻射予熱帯３、炉本体
１が連成されており、前記炉本体１は、鋼板移送方向に
沿って第１ゾーン１１から第４ゾーン１４に区画されて
おり、各ゾーンには−又は二基上のバーナ（図示省略）
が備えられている。各ゾーンは、仕切壁４によって区分
されている。該仕切壁４を設けることによって、各ゾー
ンの燃焼負荷の調整が容易になる。尚、炉本体１中には
鋼板搬送用のハースロール（図示省略）が鋼板移送方向
に沿って連設されている。(Example) Fig. 1 shows an example of a direct-fired heating furnace for carrying out the present invention, in which a convection preheating zone 2, a convection preheating zone 2, A radiant preheating zone 3 and a furnace main body 1 are coupled, and the furnace main body 1 is divided into a first zone 11 to a fourth zone 14 along the steel plate transfer direction, and each zone has one or two furnaces. Upper burner (not shown)
is provided. Each zone is divided by a partition wall 4. By providing the partition wall 4, the combustion load in each zone can be easily adjusted. In the furnace body 1, hearth rolls (not shown) for conveying the steel plate are arranged in series along the direction of conveying the steel plate.
第２図に、前記加熱炉を用いて本発明方法を実施するた
めの炉操業パターンの一例を示す。同図には、従来の炉
操業パターンも併せて示した。図中、Ａ、ａは炉ガス温
度、Ｂ、ｂは鋼板温度、Ｄ。FIG. 2 shows an example of a furnace operation pattern for carrying out the method of the present invention using the heating furnace. The figure also shows the conventional furnace operation pattern. In the figure, A and a are furnace gas temperatures, B and b are steel plate temperatures, and D.
ｄは燃焼負荷、Ｅ、ｅはトータル空気比であり、Ｆ、ｆ
は酸化領域、０２ｇは還元領域であり、大文字は本発明
実施例、小文字は従来例を示す。前記トータル空気比と
は、最後段ゾーンから当該ゾーンまでの燃料全量に対す
る空気比をいう。d is the combustion load, E, e are the total air ratio, F, f
02g is an oxidized region, and 02g is a reduced region, uppercase letters indicate the embodiment of the present invention, and lowercase letters indicate the conventional example. The total air ratio refers to the air ratio to the total amount of fuel from the last stage zone to the zone.
本発明実施例の場合、第１ゾーン１１を前段ゾーンとし
て高空気比、高燃焼負荷で操業し、炉ガス温度を高温と
することによって、鋼板を象、速加熱し、４００℃〜６
００℃の間を短時間で昇温し、酸化領域Ｆの短縮を図っ
ている。これに対して、従来例では第１ゾーン１１およ
び第２ゾーン１２は低燃焼負荷で操業しているため、鋼
板温度は低く、酸化領域ｆが長く、還元領域ｇが極めて
短かくなっている。In the case of the embodiment of the present invention, the first zone 11 is used as a pre-stage zone and is operated at a high air ratio and high combustion load, and by raising the furnace gas temperature to a high temperature, the steel plate is rapidly heated to 400°C to 600°C.
The temperature is raised between 00° C. in a short time to shorten the oxidized region F. On the other hand, in the conventional example, the first zone 11 and the second zone 12 are operated at a low combustion load, so the steel plate temperature is low, the oxidation region f is long, and the reduction region g is extremely short.
実施例では、第２ゾーン１２〜第４ゾーン１４を後段ゾ
ーンとして、鋼板温度が６００℃以上を維持するように
適度の燃焼負荷とされ、還元領域Ｇを伸長させて還元を
促進している。特に、本実施例では、後段ゾーンを鋼板
出口側に沿って空気比を下げ、従来の０．８５〜０．９
５より更に小さい値（０，８〜０．６）としているので
、還元作用が強化されている。In the example, the second zone 12 to the fourth zone 14 are set as subsequent zones, and a moderate combustion load is applied to maintain the steel plate temperature at 600° C. or higher, and the reduction region G is extended to promote reduction. In particular, in this example, the air ratio in the latter zone is lowered along the steel plate exit side, which is lower than the conventional 0.85 to 0.9.
Since the value is set to be even smaller than 5 (0.8 to 0.6), the reducing action is strengthened.
また、各ゾーンの空気比を鋼板入口側に沿って増大させ
、未燃分を多く含む燃焼ガスを前段ゾーンおよびこれに
臨接するゾーンで一気に燃焼させ、前段ゾーンの高負荷
加熱を一層容易ならしめでいる。前段ゾーンおよびこれ
に臨接するゾーンでは、既に炉ガス温度が１０００”Ｃ
程度以上の高温状態となっているので、未燃分のガスの
燃焼は極めて容易である。In addition, the air ratio in each zone is increased along the steel plate inlet side, and the combustion gas containing a large amount of unburned matter is combusted at once in the front zone and the zone adjacent to it, making it easier to perform high-load heating in the front zone. I'm here. In the front zone and the zone adjacent to it, the furnace gas temperature has already reached 1000"C.
Since the temperature is above that level, it is extremely easy to burn the unburned gas.
第２図では、実施例において、第１ゾーン１１を前段ゾ
ーンとしたが、鋼板の加熱条件により、例えば厚板では
第１ゾーン１１および第２ゾーン１２を前段ゾーンとし
てもよい。また、゛例えば薄板では、第１ゾーン１１を
休止乃至４００℃以下の予熱用として操業するに止め、
第２ゾーンを高麺焼負荷で操業する前段ゾーンとして使
用してもよい。また、鋼板の急速加熱をより容易に行う
には、前段ゾーンのバーナを鋼板に接近させたり、強制
噴流バーナを採用することも有効である。また、本発明
は竪形炉その他の形式の直火式加熱炉に適用可能なこと
は勿論である。In FIG. 2, in the embodiment, the first zone 11 is set as the front stage zone, but depending on the heating conditions of the steel plate, for example, in the case of a thick plate, the first zone 11 and the second zone 12 may be set as the front stage zone. In addition, for example, in the case of thin plates, the first zone 11 is only operated for resting or preheating to 400°C or less;
The second zone may be used as a pre-stage zone operated with a high noodle baking load. Furthermore, in order to more easily rapidly heat the steel plate, it is effective to bring the burner in the front zone closer to the steel plate or to use a forced jet burner. Furthermore, it goes without saying that the present invention is applicable to vertical furnaces and other types of direct-fired heating furnaces.
また、実施例では、第１ゾーン１１におけるトータル空
気比を１として、後続の各ゾーンにおける未燃ガスを完
全燃焼するようにしているが、従来と同様、未燃ガスは
燃焼ガスと共に後段ゾーンから前段ゾーンへ、更には予
熱帯へ送り込み、補足空気を投入して完全燃焼させて排
気してもよい。In addition, in the embodiment, the total air ratio in the first zone 11 is set to 1 to completely burn the unburned gas in each subsequent zone, but as in the past, the unburned gas is transferred from the subsequent zone together with the combustion gas. The fuel may be sent to the pre-stage zone and further to the pre-heating zone, supplementary air may be introduced, and the fuel may be completely combusted and exhausted.
（発明の効果）
以上説明した通り、本発明によれば、鋼板昇温過程にお
ける４００〜６００℃の酸化促進領域の短縮および還元
領域の拡張が図られ、従来技術に比べて格段に優れた還
元効果が得られる。また、後段ゾーンの空気比を下げる
ことにより、より一層の還元効果が期待される。(Effects of the Invention) As explained above, according to the present invention, the oxidation promotion region of 400 to 600°C in the steel plate temperature raising process is shortened and the reduction region is expanded, resulting in significantly superior reduction compared to the conventional technology. Effects can be obtained. Further, by lowering the air ratio in the latter zone, a further reduction effect is expected.
その結果、直火式加熱炉の後部に連設される還元炉の還
元負荷の低減が図られるほか、酸化膜残存によるめっき
不良の低減が図られる。また、酸化鉄の生成自体が抑制
されるため、還元鉄量自体も低減され、これに伴って還
元後の鋼板表面に形成された多孔質層の形成も可及的に
防止され、めっき後の合金化品質の向上が図られる。更
に、酸化鉄および還元鉄による炉内ハースロールへの付
着も防止され、鋼板表面疵の発生も大幅に軽減される。As a result, the reduction load on the reduction furnace connected to the rear of the direct-fired heating furnace is reduced, and plating defects due to residual oxide film are reduced. In addition, since the production of iron oxide itself is suppressed, the amount of reduced iron itself is also reduced, and the formation of a porous layer on the surface of the steel sheet after reduction is also prevented as much as possible, and the Alloying quality is improved. Furthermore, adhesion of iron oxide and reduced iron to the hearth roll in the furnace is also prevented, and the occurrence of surface flaws on the steel sheet is significantly reduced.
第１図は直火式加熱炉の一例を示す断面説明図、第２図
は実施例に係る炉操業バタン図、第３図は加熱速度を示
すグラフ図、第４図および第５図は鋼板温度と酸化膜厚
との関係を示すグラフ図である。
特 許 出 願 人 株式会社神戸製鋼所第３図
第５ 図
硝板渫炙（’Ｃ）Fig. 1 is a cross-sectional explanatory diagram showing an example of a direct-fired heating furnace, Fig. 2 is a diagram of the furnace operation according to the example, Fig. 3 is a graph showing the heating rate, and Figs. 4 and 5 are steel plates. FIG. 3 is a graph diagram showing the relationship between temperature and oxide film thickness. Patent applicant: Kobe Steel, Ltd. Figure 3 Figure 5
Claims (2)
炉に鋼板を通過させ、未燃分を含んだ還元性の燃焼ガス
によって鋼板を直接加熱する方法において、 鋼板入口側の前段ゾーンを高負荷燃焼とし、少なくとも
鋼板温度が４００℃から６００℃になるまでの間、鋼板
を急速加熱することを特徴とする鋼板の加熱方法。(1) In a method in which the steel plate is passed through a heating furnace equipped with burners and has multiple combustion zones, and the steel plate is directly heated by reducing combustion gas containing unburned matter, the front zone on the inlet side of the steel plate is heated to a high temperature. A method for heating a steel plate, characterized in that the steel plate is rapidly heated at least until the steel plate temperature reaches from 400°C to 600°C using load combustion.
り小さくし、急速加熱した鋼板を通過させることを特徴
とする請求項（１）の鋼板の加熱方法。(2) The method for heating a steel plate according to claim 1, characterized in that the air ratio in the latter zone on the steel plate outlet side is made smaller than that in the former zone, and the rapidly heated steel plate is passed therethrough.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17785988A JPH0230720A (en) | 1988-07-16 | 1988-07-16 | Method for heating steel sheet |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17785988A JPH0230720A (en) | 1988-07-16 | 1988-07-16 | Method for heating steel sheet |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0230720A true JPH0230720A (en) | 1990-02-01 |
Family
ID=16038335
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17785988A Pending JPH0230720A (en) | 1988-07-16 | 1988-07-16 | Method for heating steel sheet |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0230720A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010202959A (en) * | 2009-03-06 | 2010-09-16 | Jfe Steel Corp | Continuous hot dip galvanizing device and method for producing hot dip galvanized steel sheet |
| US20150013847A1 (en) * | 2012-03-09 | 2015-01-15 | Baoshan Iron & Steel Co., Ltd. | Method for Producing Silicon Steel Normalizing Substrate |
| JP2018162486A (en) * | 2017-03-24 | 2018-10-18 | 株式会社神戸製鋼所 | Heating method for hot-dip zinc-coated steel sheet |
-
1988
- 1988-07-16 JP JP17785988A patent/JPH0230720A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010202959A (en) * | 2009-03-06 | 2010-09-16 | Jfe Steel Corp | Continuous hot dip galvanizing device and method for producing hot dip galvanized steel sheet |
| US20150013847A1 (en) * | 2012-03-09 | 2015-01-15 | Baoshan Iron & Steel Co., Ltd. | Method for Producing Silicon Steel Normalizing Substrate |
| US9822423B2 (en) * | 2012-03-09 | 2017-11-21 | Baoshan Iron & Steel, Co., Ltd. | Method for producing silicon steel normalizing substrate |
| JP2018162486A (en) * | 2017-03-24 | 2018-10-18 | 株式会社神戸製鋼所 | Heating method for hot-dip zinc-coated steel sheet |
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