JPH05295488A - Al-added high-purity fe-cr alloy excellent in oxidation resistance - Google Patents

Abstract

PURPOSE:To manufacture a high-purity Fe-Cr alloy excellent in oxidation resis tance as excellent in workability, in an Al-added Fe-Cr alloy contg. Fe, Cr and Al, by prescribing the content of each element. CONSTITUTION:As a raw material, an ultrahigh purity electrolytic iron, electrolytic Cr and electrolytic Al are used and are melted and cast in a ultrahigh vacuum of >=10<->7Torr to manufacture an Fe-Cr alloy having super high purity. At this time, the content (wt.%) of each element is allowed to satisfy the conditions of Fe+Cr+Al>=99.98, 99.5>=Cr+Al>=0.5 and 20>=Al>=0.001, and, preferably, the content of Al is regulated to 0.01 to 20%, and that of Cr to 3 to 30%. In this way, the objective Fe-Cr-Al alloy excellent in oxidation resistance as well as excellent in workability can be obtd.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は耐酸化性に優れ、かつ加
工性にも優れる高純度のＦｅ−Ｃｒ系合金に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-purity Fe-Cr alloy having excellent oxidation resistance and workability.

【０００２】[0002]

【従来の技術】一般にＦｅ−Ｃｒ合金は耐食性に優れた
材料として知られているが、耐食性、加工性および耐酸
化性の改善も含めてＦｅ−Ｃｒ合金の物性の改良が各種
提案されている。2. Description of the Related Art Generally, an Fe--Cr alloy is known as a material having excellent corrosion resistance, and various proposals have been made to improve the physical properties of the Fe--Cr alloy including improvement of corrosion resistance, workability and oxidation resistance. ..

【０００３】例えば、特開平１−２８７２５３号公報で
はＣｒ含量１５〜２６重量％、Ａｌ含量４〜６重量％の
Ｆｅ−Ｃｒ−Ａｌ合金であって、希土類元素を少量特定
量含有せしめた耐酸化性および製造性に優れたＡｌ含有
フェライト系ステンレス鋼を提案している。For example, in Japanese Unexamined Patent Publication (Kokai) No. 1-287253, an Fe-Cr-Al alloy having a Cr content of 15 to 26% by weight and an Al content of 4 to 6% by weight, containing a small amount of a rare earth element in a specified amount, has an oxidation resistance. We propose an Al-containing ferritic stainless steel that is excellent in workability and manufacturability.

【０００４】[0004]

【発明が解決しようとする課題】上記公報において提案
された耐酸化性Ｆｅ−Ｃｒ−Ａｌ合金は耐酸化性におい
てはある程度の特性が得られるものの、高Ｃｒ，高Ａｌ
とコスト的に高く、また従来のフェライト系ステンレス
鋼に比べて成形加工性や製造性に劣るという問題があっ
た。したがって、耐酸化性と成形加工性のバランスを取
ることが非常に困難で、後者を犠牲にせざるを得なかっ
た。The oxidation-resistant Fe-Cr-Al alloy proposed in the above publication has some characteristics in oxidation resistance, but it is high in Cr and high in Al.
Therefore, there is a problem that the cost is high, and the formability and the manufacturability are inferior to the conventional ferritic stainless steel. Therefore, it is very difficult to balance the oxidation resistance and the molding processability, and the latter must be sacrificed.

【０００５】かくして、本発明は著しく耐酸化性に優
れ、しかも加工性においても優れるＦｅ−Ｃｒ−Ａｌ系
合金を提供することを目的とする。Thus, it is an object of the present invention to provide a Fe-Cr-Al based alloy which is remarkably excellent in oxidation resistance and is also excellent in workability.

【０００６】[0006]

【課題を解決するための手段】本発明者は、上記目的を
達成すべく鋭意研究を行った結果、従来Ｆｅ−Ｃｒ合金
に存在していたＣ，Ｎ，Ｏ，Ｐ，Ｓ，Ｓｉ，Ｍｎ，Ｍ
ｏ，Ｔｉ，Ｎｂ，Ｚｒ，Ｗ，Ｖ，Ｔａ，Ｂ，Ｃｕ，Ｎ
ｉ，Ｃｏ，Ｃａ，Ｍｇなどの不純物を低下させ、さらに
Ａｌを添加した高純度Ｆｅ−Ｃｒ−Ａｌ系合金が上記目
的を達成することを見い出し、本発明を完成するに至っ
た。As a result of earnest studies to achieve the above object, the present inventor has found that C, N, O, P, S, Si and Mn, which have been conventionally present in Fe-Cr alloys. , M
o, Ti, Nb, Zr, W, V, Ta, B, Cu, N
The inventors have found that a high-purity Fe-Cr-Al-based alloy in which impurities such as i, Co, Ca, and Mg are reduced and Al is further added achieves the above object, and the present invention has been completed.

【０００７】すなわち、本発明によればＦｅ，Ｃｒ，Ａ
ｌを含むＡｌ添加Ｆｅ−Ｃｒ系合金であって、各元素の
含有量（重量％）が下記条件（１）〜（３）を満たすこ
とを特徴とする耐酸化性に優れたＡｌ添加高純度Ｆｅ−
Ｃｒ系合金が提供される。 （１）Ｆｅ＋Ｃｒ＋Ａｌ≧９９．９８ （２）９９．５≧Ｃｒ＋Ａｌ≧０．５ （３）２０≧Ａｌ≧０．００１That is, according to the present invention, Fe, Cr, A
An Al-added Fe-Cr alloy containing 1 and having a content (% by weight) of each element satisfying the following conditions (1) to (3), which is excellent in oxidation resistance: Al-added high purity Fe-
A Cr-based alloy is provided. (1) Fe + Cr + Al ≧ 99.98 (2) 99.5 ≧ Cr + Al ≧ 0.5 (3) 20 ≧ Al ≧ 0.001

【０００８】[0008]

【作用】本発明の理解のために、図面等を用いて本発明
の作用を説明する。図１は、供試材（Ｆｅ−２０％Ｃｒ
−５．２％Ａｌ）の伸びを測定した結果を示すものであ
る。この図から明らかなように、Ｆｅ，Ｃｒ，Ａｌ以外
の成分の総和が０．０２重量％以下、即ちＦｅとＣｒの
合計量が９９．９８％以上の場合において伸び（延性）
が極めて高いことが明らかである。なお、供試材の調製
法および測定方法は、以下の通りである。To understand the present invention, the operation of the present invention will be described with reference to the drawings. Figure 1 shows the test material (Fe-20% Cr
It shows the result of measuring the elongation of -5.2% Al). As is clear from this figure, elongation (ductility) occurs when the sum of components other than Fe, Cr, and Al is 0.02% by weight or less, that is, when the total amount of Fe and Cr is 99.98% or more.
Is very high. The methods for preparing and measuring the test materials are as follows.

【０００９】供試材：１０ｋｇ真空炉で溶解、鋳造し、
熱間で４ｍｍ厚まで圧延後、再結晶焼鈍し、脱スケール
後冷間で０．７ｍｍ厚まで圧延後、再結晶焼鈍し、供試
材とした。 測定方法：試験片を圧延方向に対してＬ方向、Ｃ方向、
Ｘ方向より採取し、ＪＩＳ Ｚ−２２４１に準拠した引
張試験により（Ｌ＋Ｃ＋２×Ｘ）／４で求めた。Test material: Melted and cast in a 10 kg vacuum furnace,
After hot rolling to a thickness of 4 mm, recrystallization annealing was performed, and after descaling, cold rolling was performed to a thickness of 0.7 mm, and recrystallization annealing was performed to obtain a test material. Measuring method: L-direction, C-direction,
It was sampled from the X direction and determined by (L + C + 2 × X) / 4 by a tensile test according to JIS Z-2241.

【００１０】図２は、ＣｒとＡｌの合計量と耐酸化性の
関係を示すグラフである。このグラフからＣｒとＡｌの
合計量が０．５重量％以上となると耐酸化性が向上する
ことが明らかである。FIG. 2 is a graph showing the relationship between the total amount of Cr and Al and oxidation resistance. From this graph, it is clear that the oxidation resistance is improved when the total amount of Cr and Al is 0.5% by weight or more.

【００１１】なお、試料の調製および耐酸化性の測定方
法は以下のごとくである。 試験片：１０ｋｇ真空炉で溶解、鋳造し、熱間で４ｍｍ
厚まで圧延後、再結晶焼鈍し、脱スケール後冷間で０．
６ｍｍ厚まで圧延後、再結晶焼鈍し、表面をエメリー＃
５００研磨し試験片とした。 測定方法：大気中、１０５０℃の炉内に２４時間保持し
た後の酸化増量を求めた。The method for preparing the sample and measuring the oxidation resistance is as follows. Test piece: 10 kg, melted and cast in a vacuum furnace, hot 4 mm
After rolling to thickness, recrystallization annealing was performed, and descaling was followed by cold cooling.
After rolling to a thickness of 6 mm, recrystallization annealing is performed and the surface is emery #
It was ground to 500 to obtain a test piece. Measurement method: The amount of increased oxidation was determined after holding in a furnace at 1050 ° C. for 24 hours in the air.

【００１２】表１にＡｌ含量と耐異常酸化性（break aw
ayの有無）の関係を示すデータを示す。ここで、break
away（異常酸化）とは、局部的にそれまで生じていた緻
密な酸化皮膜が破れ、急激な酸化が生じるということで
あり、耐酸化性の点からは生じないことが好ましい。こ
のデータからＡｌ含量が０．００１重量％以上であれ
ば、break awayの発生が無く、耐異常酸化性に優れるこ
とが明らかである。Table 1 shows Al content and abnormal oxidation resistance (break aw).
The following shows data indicating the relationship of the presence or absence of ay. Where break
The away (abnormal oxidation) means that the dense oxide film that has been locally formed is broken and rapid oxidation occurs, and it is preferable that it does not occur from the viewpoint of oxidation resistance. From this data, it is clear that when the Al content is 0.001% by weight or more, breakaway does not occur and the abnormal oxidation resistance is excellent.

【００１３】 [0013]

【００１４】なお、使用した試験片と測定方法は下記の
ごとくである。 試験片（２０％Ｃｒ系）：１０ｋｇ真空炉で溶解、鋳造
し、熱間で４ｍｍ厚まで圧延後、再結晶焼鈍し、脱スケ
ール後、冷間で０．６ｍｍ厚まで圧延後、再結晶焼鈍
し、表面をエメリー＃５００研磨し試験片とした。 測定、評価方法：大気中、１１２５℃の炉内に所定の時
間保持し、外観観察により、break away（異常酸化）の
有無を目視判定した。 ○：break away発生せず ×：break away発生The test pieces used and the measuring method are as follows. Test piece (20% Cr system): Melted and cast in a 10 kg vacuum furnace, hot rolled to a thickness of 4 mm, recrystallized and annealed, descaled, cold rolled to a thickness of 0.6 mm, and recrystallized and annealed. Then, the surface was polished with Emery # 500 to obtain a test piece. Measurement and evaluation method: The presence of break away (abnormal oxidation) was visually judged by observing the external appearance by holding in a furnace at 1125 ° C. for a predetermined time in the atmosphere. ○: No break away occurred ×: Break away occurred

【００１５】[0015]

【構成】以下、本発明の構成を詳述するが、より好まし
い態様およびそれに基づく利点が明らかとなろう。[Structure] The structure of the present invention will be described in detail below, but more preferable embodiments and advantages based thereon will become apparent.

【００１６】本発明のＡｌ添加Ｆｅ−Ｃｒ系合金のＦ
ｅ，ＣｒおよびＡｌの合計量は９９．９８重量％以上で
ある。９９．９８重量％未満であると、〔作用〕の項で
述べたように延性が低下すると共に、耐酸化性も低下す
る。Ｆｅ，ＣｒおよびＡｌの合計量が上記の範囲である
と延性において優れ、加工性が良い。F of the Al-added Fe-Cr alloy according to the present invention
The total amount of e, Cr and Al is 99.98% by weight or more. If it is less than 99.98% by weight, the ductility is lowered as described in the section [Operation] and the oxidation resistance is also lowered. When the total amount of Fe, Cr and Al is in the above range, the ductility is excellent and the workability is good.

【００１７】本発明の合金では、ＣｒとＡｌの合計量は
０．５〜９９．５重量％、好ましくは６〜４０重量％で
ある。前記作用の項で記載したように、この範囲である
ことにより耐酸化性において著しく優れたＦｅ−Ｃｒ−
Ａｌ系合金が得られる。なお、９９．５重量％を越えた
場合、経済的合理性がない。In the alloy of the present invention, the total amount of Cr and Al is 0.5 to 99.5% by weight, preferably 6 to 40% by weight. As described in the section of the above-mentioned action, within this range, Fe-Cr- which is remarkably excellent in oxidation resistance.
An Al-based alloy is obtained. If it exceeds 99.5% by weight, it is not economically rational.

【００１８】また、Ａｌの含量は０．０１〜２０重量
％、好ましくは０．５〜７重量％である。Ａｌ含量が過
少であると耐異常酸化性に乏しく、過剰であると経済的
合理性を失う。The Al content is 0.01 to 20% by weight, preferably 0.5 to 7% by weight. If the Al content is too small, the abnormal oxidation resistance is poor, and if it is excessive, economic rationality is lost.

【００１９】さらにＣｒ含量は、好ましくは３〜３０重
量％である。この範囲であると、耐酸化性のみならず耐
食性にも優れるからである。Further, the Cr content is preferably 3 to 30% by weight. This is because in this range, not only oxidation resistance but also corrosion resistance is excellent.

【００２０】以上のような超高純度のＡｌ添加Ｆｅ−Ｃ
ｒ系合金の製造は、原料として超高純度電解鉄、電解Ｃ
ｒおよび電解Ａｌを所定量用いることで達成される。い
ずれの原料も、主たる不純物は酸素であり、この酸素を
除去するために、１０^-7ｔｏｒｒよりも高い超高真空下
で溶解、鋳造することにより本発明の超高純度のＦｅ−
Ｃｒ系合金を製造することができる。また、本発明合金
は、熱延焼鈍板、冷延焼鈍板で用いられても十分に効果
が生じるとともに、冷延焼鈍板においては、表面仕上げ
が２Ｄ、２Ｂ、ＢＡ、ＨＬ、研磨、鏡面などのいずれで
もかまわない。Ultra-high purity Al-added Fe-C as described above
The production of r-based alloys uses ultra-high purity electrolytic iron and electrolytic C as raw materials.
This is achieved by using a predetermined amount of r and electrolytic Al. The main impurity of any of the raw materials is oxygen, and in order to remove this oxygen, by melting and casting under ultrahigh vacuum higher than 10 ⁻⁷ torr, the ultrahigh purity Fe— of the present invention is produced.
A Cr-based alloy can be manufactured. Further, the alloy of the present invention produces a sufficient effect even when used in a hot-rolled annealed plate or a cold-rolled annealed plate, and in the cold-rolled annealed plate, the surface finish is 2D, 2B, BA, HL, polishing, mirror surface, etc. It doesn't matter.

【００２１】[0021]

【実施例】【Example】

〔実施例〕表２に示す化学組成を有する合金を１０ｋｇ
真空溶解炉で溶製、鋳造し、熱間圧延により板厚４ｍｍ
の熱延板とし、再結晶を目的とした熱延板焼鈍を施し、
脱スケール後冷間圧延により板厚０．７ｍｍの冷延板と
して最終的に再結晶焼鈍し、冷延焼鈍板とした。[Example] 10 kg of an alloy having the chemical composition shown in Table 2
Melted and cast in a vacuum melting furnace, and hot rolled to a plate thickness of 4 mm
As a hot-rolled sheet of, subjected to hot-rolled sheet annealing for the purpose of recrystallization,
After descaling, cold rolling was performed by cold rolling to obtain a cold rolled sheet having a thickness of 0.7 mm, which was finally recrystallized and annealed to obtain a cold rolled annealed sheet.

【００２２】 [0022]

【００２３】このようにして得られた合金板について以
下の試験を行った。 〔加工性の評価〕発明合金１，２，４と比較合金１，
４，７を用いてＪＩＳ Ｚ−２２４１に準拠した引張試
験による伸びの値を測定し、５０％冷間圧延後、Ｃ方向
に１８０°密着曲げ試験を行った時の割れの状況観察を
行い、割れなしの場合○、割れありの場合×と評価し
た。その結果を表３に示す。The following tests were carried out on the alloy plate thus obtained. [Evaluation of workability] Invention alloys 1, 2, 4 and comparative alloy 1,
4, the value of elongation by a tensile test according to JIS Z-2241 was measured, and after 50% cold rolling, the state of cracks was observed when a 180 ° contact bending test was performed in the C direction, When there was no crack, it was evaluated as ○, and when there was crack, it was evaluated as ×. The results are shown in Table 3.

【００２４】 Ｆｅ，ＣｒおよびＡｌの合計量を９９．９８重量％以上
とすることにより、著しく加工性が改善されることがわ
かる。[0024] It is understood that the workability is remarkably improved by setting the total amount of Fe, Cr and Al to 99.98% by weight or more.

【００２５】〔耐酸化性の評価〕発明合金１および比較
合金２の表面をエメリー＃５００研磨し、大気中１００
０℃の炉中に２４時間保持した後の酸化増量により耐酸
化性を評価した結果、発明合金１の場合３２ｍｇ／ｃｍ
² 、比較合金２の場合１２ｍｇ／ｃｍ² の酸化増量であ
った。Ｃｒ＋Ａｌの合計量を０．４１１重量％から０．
５６０％とすることにより酸化増量が１／３程度とな
り、著しく耐酸化性が改善されることがわかる。[Evaluation of Oxidation Resistance] The surfaces of the invention alloy 1 and the comparative alloy 2 were emery # 500-polished and then exposed to 100 in air.
As a result of evaluating the oxidation resistance by increasing the amount of oxidation after holding in a furnace at 0 ° C. for 24 hours, in the case of the invention alloy 1, 32 mg / cm
² , the comparative alloy 2 had an oxidation increase of 12 mg / cm ² . The total amount of Cr + Al is 0.411% by weight to 0.
It can be seen that when the content is 560%, the amount of increase in oxidation becomes about 1/3, and the oxidation resistance is remarkably improved.

【００２６】〔耐異常酸化性の評価〕発明合金２，３，
４および比較合金３，５，６の表面をエメリー＃５００
研磨し、大気中１１２５℃の炉中に保持した時のbreak
away発生状況を調査した結果を表４に示す。[Evaluation of Abnormal Oxidation Resistance] Inventive Alloys 2, 3
4 and comparative alloys 3, 5 and 6 with emery # 500
Break when polished and held in a furnace at 1125 ° C in air
Table 4 shows the result of the investigation of the occurrence situation of away.

【００２７】 [0027]

【００２８】Ａｌ量が０．００１％以上含有した試料で
は、break awayは認められず、耐異常酸化性に著しく優
れていることがわかる。In the sample containing 0.001% or more of Al, no break away was observed, and it can be seen that abnormal oxidation resistance is remarkably excellent.

【００２９】[0029]

【発明の効果】本発明のＡｌ添加高純度Ｆｅ−Ｃｒ系合
金は、著しく耐酸化性に優れ、しかも加工性においても
優れ、自動車排ガスコンバータ材や燃焼バーナー材など
の用途に用いることができる。The Al-added high-purity Fe-Cr alloy according to the present invention has remarkably excellent oxidation resistance and also excellent workability, and can be used for applications such as automobile exhaust gas converter materials and combustion burner materials.

【図面の簡単な説明】[Brief description of drawings]

【図１】 Ｆｅ，Ｃｒ，Ａｌ以外の成分の和と伸びの関
係を示すグラフである。FIG. 1 is a graph showing the relationship between the sum of components other than Fe, Cr, and Al and elongation.

【図２】 ＣｒとＡｌの合計量と耐酸化性を示すグラフ
である。FIG. 2 is a graph showing the total amount of Cr and Al and oxidation resistance.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 矢 沢 好 弘 千葉県千葉市中央区川崎町１番地 川崎製 鉄株式会社技術研究本部内 (72)発明者 大和田 哲 千葉県千葉市中央区川崎町１番地 川崎製 鉄株式会社技術研究本部内 (72)発明者 藤 澤 光 幸 千葉県千葉市中央区川崎町１番地 川崎製 鉄株式会社技術研究本部内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Yazawa 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Technical Research Division, Kawasaki Steel Corporation (72) Inventor Satoshi Owada Kawasaki-cho, Chuo-ku, Chiba-shi No. 1 Kawasaki Iron & Steel Co., Ltd. Technical Research Headquarters (72) Inventor Mitsuyuki Fujisawa No. 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Iron & Steel Co., Ltd. Technical Research Headquarters

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】Ｆｅ，Ｃｒ，Ａｌを含むＡｌ添加Ｆｅ−Ｃ
ｒ系合金であって、各元素の含有量（重量％）が下記条
件（１）〜（３）を満たすことを特徴とする耐酸化性に
優れたＡｌ添加高純度Ｆｅ−Ｃｒ系合金。 （１）Ｆｅ＋Ｃｒ＋Ａｌ≧９９．９８ （２）９９．５≧Ｃｒ＋Ａｌ≧０．５ （３）２０≧Ａｌ≧０．００１1. An Al-added Fe-C containing Fe, Cr and Al.
A high purity Fe-Cr alloy containing Al and having excellent oxidation resistance, characterized in that the content (% by weight) of each element satisfies the following conditions (1) to (3). (1) Fe + Cr + Al ≧ 99.98 (2) 99.5 ≧ Cr + Al ≧ 0.5 (3) 20 ≧ Al ≧ 0.001