JP4261602B2 - Manufacturing method of high cleanliness steel - Google Patents
Manufacturing method of high cleanliness steel Download PDFInfo
- Publication number
- JP4261602B2 JP4261602B2 JP2007263204A JP2007263204A JP4261602B2 JP 4261602 B2 JP4261602 B2 JP 4261602B2 JP 2007263204 A JP2007263204 A JP 2007263204A JP 2007263204 A JP2007263204 A JP 2007263204A JP 4261602 B2 JP4261602 B2 JP 4261602B2
- Authority
- JP
- Japan
- Prior art keywords
- steel
- inclusions
- maximum
- diameter
- high cleanliness
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
Description
本発明は、鋼を鋳造する場合において、清浄度の高い鋼片の製造方法に関するものである。 The present invention relates to a method for producing a steel slab having a high cleanliness when casting steel.
鋼を製造する際に、非金属介在物は不可避的に発生する。この介在物は通常精錬時に浮上分離するが、精錬終了時に溶鋼内に残存し、その後の鋳込み時に直送流に乗り鋼片に補足されるものもある。 When manufacturing steel, non-metallic inclusions are inevitably generated. These inclusions usually float and separate at the time of refining, but remain in the molten steel at the end of refining, and some of the inclusions are caught in the direct feed flow and supplemented by the steel slab at the time of subsequent casting.
それらの非金属介在物は、鋼材が製品になった際に応力が集中し割れの起点となり得るため、極力除去する必要がある。しかし、完全に除去することは不可能であるため、製品内に残留する介在物の最大径をある大きさ以下に保証することが必要である。保証する介在物の最大径は保証したい鋼の量が大きくなればなるほど大きくなる。しかし、この出願において保証したい介在物の最大径のイメージは、５０ｇの鋼をスライム溶解したときに出現する介在物の最大径である。 These non-metallic inclusions need to be removed as much as possible because stress concentrates and can become a starting point of cracking when steel becomes a product. However, since it is impossible to remove completely, it is necessary to guarantee the maximum diameter of inclusions remaining in the product to a certain size or less. The maximum diameter of inclusions to be guaranteed increases as the amount of steel to be guaranteed increases. However, the image of the maximum diameter of inclusions to be guaranteed in this application is the maximum diameter of inclusions that appears when 50 g of steel is melted with slime.
このような介在物を低減して小径化する手段として、精錬時の脱ガス時間を長くして介在物の浮上分離を促す手段（非特許文献１参照）がある。これによると、介在物の浮上分離にはある大きさ以上の径が必要であり、かつ、径が大きければ大きいほどその浮力により分離し易くなる。しかし、従来技術では清浄度を得るために必要以上のキリング時間を設定したり、キリング時間が短く清浄度の高い鋼を得られないことがあった。 As means for reducing the size of inclusions by reducing the diameter, there is a means (see Non-Patent Document 1) for increasing the degassing time during refining to promote floating separation of inclusions. According to this, for the floating separation of inclusions, a diameter of a certain size or more is required, and the larger the diameter, the easier it is to separate by the buoyancy. However, in the prior art, an excessive killing time may be set to obtain cleanliness, or a steel with a short killing time and high cleanliness may not be obtained.
また、ＥＳＺ方式を応用した「介在物粒径分布測定法」が製鋼においても実用化されている（非特許文献２参照）。この方法を用いれば精錬最終工程後の溶鋼中の介在物の粒径分布を迅速に得ることができる。 Further, the “inclusion particle size distribution measurement method” applying the ESZ method has been put into practical use in steelmaking (see Non-Patent Document 2). By using this method, the particle size distribution of inclusions in the molten steel after the final refining process can be obtained quickly.
本発明が解決しようとする課題は、溶鋼に残存する有害な非金属介在物が非常に少ない清浄度の高い鋼を必要十分な工程で精度良く製造する方法を提供することである。 The problem to be solved by the present invention is to provide a method for accurately producing a steel having a high degree of cleanliness with a very small amount of harmful non-metallic inclusions remaining in the molten steel in a necessary and sufficient process.
上記の課題を解決するための本発明の手段は、精錬終了時に製品で保証したい介在物径に応じてキリング時間を設定する。さらに、介在物センサーを用い精錬最終工程の溶鋼中の介在物の粒径最大値を得た後、その粒径最大値が保証したい介在物径以上だった場合に、キリングすることで高清浄度鋼を得る方法である。すなわち、請求項１の発明では、製品で保証したい介在物の最大径に応じて、取鍋精錬におけるキリング時間を下記の式（１）内のｔ秒±１０％に確保することを特徴とする高清浄度鋼製造方法である。 The means of the present invention for solving the above-mentioned problems sets the killing time according to the inclusion diameter to be guaranteed by the product at the end of refining. Furthermore, after obtaining the maximum particle size of inclusions in molten steel in the final refining process using an inclusion sensor, if the maximum particle size is greater than the inclusion size that you want to guarantee, high cleanliness is achieved by killing. It is a method of obtaining steel. That is, the invention of claim 1 is characterized in that the killing time in ladle refining is secured at t seconds ± 10% in the following formula (1) according to the maximum diameter of inclusions to be guaranteed in the product. It is a high cleanliness steel manufacturing method.
ｔ＝１．８×１０6・ｈ／Ｄ2 （１）
ただし、ｔ：キリング時間（秒）
ｈ：取鍋内溶鋼深さ（ｍ）
Ｄ：製品で保証したい介在物最大径（μｍ）
t = 1.8 × 10 6 · h / D 2 (1)
Where t: Killing time (seconds)
h: Molten steel depth in the ladle (m)
D: Maximum inclusion diameter (μm) to be guaranteed in the product
条件設定理由について以下に説明する。精錬時に生成する介在物は溶鋼よりも比重が軽いため浮上しようとする性質がある。ところで、この浮上速度はストークスの法則に支配されており、清浄度を悪化させる介在物の浮上速度を推定することができる。ある浮上時間（すなわち、キリング時間）を規定することで鋼中の有害な大型の非金属介在物を低減することが可能である。 The reason for setting conditions will be described below. Inclusions generated during refining have the property of floating because the specific gravity is lighter than molten steel. By the way, this ascent rate is governed by Stokes' law, and it is possible to estimate the ascending rate of inclusions that deteriorate the cleanliness. It is possible to reduce harmful large non-metallic inclusions in the steel by defining a certain ascent time (ie kill time).
さらに、介在物の粒径分布は精錬の諸条件により大きく変動するため、精錬終了時の粒径の最大値を把握できればキリングする必要があるかどうかの判断ができる。 Furthermore, since the particle size distribution of inclusions varies greatly depending on various conditions of refining, it can be determined whether or not killing is necessary if the maximum value of the particle size at the end of refining can be grasped.
従って精錬最終工程の粒径最大値を確認した後、その粒径最大値が保証したい介在物径を超えていた場合のみキリング時間付加することで効率的に清浄鋼を得ることが可能となる。 Therefore, after confirming the maximum grain size value in the final refining process, it is possible to efficiently obtain clean steel by adding the killing time only when the maximum grain size value exceeds the inclusion diameter to be guaranteed.
以上説明したように、本発明における高清浄度鋼製造方法を適用することにより、従来よりも清浄度の高い鋼を精度良く製造することが可能となり、非金属介在物の少ない高清浄度スラブ、高清浄度ブルームまたは高清浄度ビレットの連続鋳造若しくは高清浄度鋼塊のインゴット鋳造に大きく寄与するものである。 As described above, by applying the high cleanliness steel manufacturing method in the present invention, it becomes possible to manufacture steel with higher cleanliness than before, with high cleanliness slabs with less non-metallic inclusions, It greatly contributes to continuous casting of high cleanliness bloom or high cleanness billets or ingot casting of high cleanliness steel ingots.
以下に本発明の実施の形態を以下の実施例を通じて説明する。 Embodiments of the present invention will be described below through the following examples.
ＪＩＳで規定する表１に示す成分範囲のＳＵＪ鋼と比較鋼を電気炉（ａ）による溶解に続いて、取鍋精錬炉（ｂ）により取鍋精錬し、ＲＨ脱ガス装置（Ｃ）により脱ガス処理した後、連続鋳造装置（ｄ）で連続鋳造するか、あるいは、インゴット鋳造設備（ｅ）により鋼塊にする工程を図１に示す。 Following the melting in the electric furnace (a), the SUJ steel and the comparative steel in the composition range shown in Table 1 specified by JIS are smelted in the ladle by the ladle smelting furnace (b) and dehydrated by the RH degasser (C). FIG. 1 shows a process in which after the gas treatment, continuous casting is performed by a continuous casting apparatus (d) or a steel ingot is formed by an ingot casting facility (e).
この図１に示す精錬および鋳造設備からなる製鋼工程において、精錬最終工程である脱ガス工程の終了時に、図２に示すように介在物センサーを用いて介在物の粒径分布を測定した。その粒径分布中の最大径によって、その後のキリング時間ｔを式（１）から求めて高清浄度鋼を得た。 In the steelmaking process comprising the refining and casting equipment shown in FIG. 1, the particle size distribution of inclusions was measured using an inclusion sensor as shown in FIG. 2 at the end of the degassing process as the final refining process. Based on the maximum diameter in the particle size distribution, the subsequent killing time t was obtained from equation (1) to obtain a high cleanliness steel.
ｔ＝１．８×１０6・ｈ／Ｄ2 （１）
ただし、ｔ：キリング時間（秒）
ｈ：取鍋内溶鋼深さ（ｍ）
Ｄ：製品で保証したい介在物最大径（μｍ）
t = 1.8 × 10 6 · h / D 2 (1)
Where t: Killing time (seconds)
h: Molten steel depth in the ladle (m)
D: Maximum inclusion diameter (μm) to be guaranteed in the product
表２は、表１に示すＳＵＪ鋼の精錬最終工程であるＲＨ脱ガス後の介在物センサーで測定した精錬終了時最大径（μｍ）と製品で保証したい介在物最大径（μｍ）を示したものである。 Table 2 shows the maximum diameter (μm) at the end of refining measured by the inclusion sensor after RH degassing, which is the final refining process of SUJ steel shown in Table 1, and the maximum diameter (μm) of inclusions to be guaranteed by the product. Is.
これらにおいて、実施例１〜３はキリング時間を上記の式（１）の計算値通りに実施したものであり、比較例は実施しなかったものである。 In these examples, Examples 1 to 3 were carried out according to the calculated values of the above formula (1), and the comparative examples were not carried out.
実施例１〜３は製品内最大介在物径が保証したい介在物最大径以下の合格の範囲にあるのに対し、比較例１は製品内介在物最大径が５４と高く不合格となっているのがわかる。また、比較例２は必要以上に清浄度の高いものが得られた例である。 In Examples 1 to 3, the maximum inclusion diameter in the product is within the range of acceptance below the maximum inclusion inclusion diameter to be guaranteed, whereas in Comparative Example 1, the maximum inclusion inclusion diameter is 54 and rejected. I understand. Further, Comparative Example 2 is an example in which a product having a higher cleanliness than necessary was obtained.
１ 電気炉
２ 取鍋
３ タンディッシュ
４ 連鋳片
５ インゴット
1
Claims (1)
ｔ＝１．８×１０6・ｈ／Ｄ2 （１）
ただし、ｔ：キリング時間（秒）
ｈ：取鍋内溶鋼深さ（ｍ）
Ｄ：製品で保証したい介在物最大径（μｍ） A method for producing a high cleanliness steel characterized in that the killing time in ladle refining is ensured to t ± 10% in the following formula (1) according to the maximum diameter of inclusions to be guaranteed in the product.
t = 1.8 × 10 6 · h / D 2 (1)
Where t: Killing time (seconds)
h: Molten steel depth in the ladle (m)
D: Maximum inclusion diameter (μm) to be guaranteed in the product
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007263204A JP4261602B2 (en) | 2007-10-09 | 2007-10-09 | Manufacturing method of high cleanliness steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007263204A JP4261602B2 (en) | 2007-10-09 | 2007-10-09 | Manufacturing method of high cleanliness steel |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2003071040A Division JP4056911B2 (en) | 2003-03-14 | 2003-03-14 | Manufacturing method of high cleanliness steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2008063666A JP2008063666A (en) | 2008-03-21 |
| JP4261602B2 true JP4261602B2 (en) | 2009-04-30 |
Family
ID=39286618
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2007263204A Expired - Fee Related JP4261602B2 (en) | 2007-10-09 | 2007-10-09 | Manufacturing method of high cleanliness steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4261602B2 (en) |
-
2007
- 2007-10-09 JP JP2007263204A patent/JP4261602B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2008063666A (en) | 2008-03-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2013125162A1 (en) | Forged steel roll manufacturing method | |
| EP2876171B1 (en) | Method for controlling a segregation of steel ingots by purification of molten steel | |
| JP5277556B2 (en) | Method for producing Ti-containing ultra-low carbon steel and method for producing Ti-containing ultra-low carbon steel slab | |
| JP5208556B2 (en) | Titanium copper suitable for precision press working and method for producing the titanium copper | |
| JP5381243B2 (en) | Method for refining molten steel | |
| CN104109760A (en) | Steel ingot medium-frequency induction furnace/electroslag furnace dual-smelting system and method and steel ingot | |
| JP6443200B2 (en) | Manufacturing method of high clean steel | |
| JP4261602B2 (en) | Manufacturing method of high cleanliness steel | |
| JP4548483B2 (en) | Casting method for molten alloy | |
| JP5598147B2 (en) | Manufacturing method of forged steel roll | |
| JP4056911B2 (en) | Manufacturing method of high cleanliness steel | |
| JP5942712B2 (en) | Scum weir, thin slab manufacturing method, thin slab manufacturing equipment | |
| JP2006326639A (en) | Method for producing maraging steel | |
| JP2005177848A (en) | Center defect reducing method of continuously cast steel slab | |
| JP5807698B2 (en) | Ingot casting method for forged steel roll production | |
| JP6515291B2 (en) | Continuous steel casting method | |
| JP2008100248A (en) | Continuously casting tundish, and method of continuous casting | |
| JP4505811B2 (en) | Casting method for molten alloy | |
| CN106350696B (en) | Copper alloy material and method for producing same | |
| JP7032600B1 (en) | Mold powder for continuous casting and continuous casting method used for Fe—Ni based alloys or Ni-based alloys. | |
| JP3712338B2 (en) | Method for producing spheroidal graphite cast iron | |
| RU2781701C2 (en) | Low alloy based on copper and its melting method | |
| JP7406074B2 (en) | Titanium ingot manufacturing method and titanium ingot manufacturing mold | |
| JP2006233254A (en) | Method for producing high cleanliness steel | |
| JPH10249498A (en) | Method for continuously casting high cleanliness steel with tundish providing field weir closing bottom part |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20081111 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20090203 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20090205 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120220 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 4261602 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130220 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130220 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140220 Year of fee payment: 5 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |