JPS61201726A - Manufacture of b-containing austenitic stainless steel - Google Patents

Abstract

PURPOSE:To manufacture the titled steel free from crack and having good quality, by surrounding steel steel ingot having a specified compsn. contg. B, Crand Ni with iron tube tightly and adhering them pressedly, then hot rolling said body under a suitable condition. CONSTITUTION:15-21% Cr, 7.0-16% Ni system austenitic stainless steel ingot contg. 0.5-3.0wt% B, as it is or shaped to rectangular state, is surrounded tightly with iron tube made of soft iron, etc. at least four main surfaces excluding both end surfaces in longitudinal direction, and said body is bloom rolled or forged to adhere them pressedly. Next, steel ingot is heated to 950-1,250 deg.C, and hot rolled by at least one time, by 10-70% draft per one pass. Then hot rolled material is, if necessary, soln. heat treated, cold rolled, leveller straightened, etc., next, iron layer at outermost layer of circumferential surface is removed, to obtain the titled steel having good quality and free from crack and flaw at rim part in longitudinal direction of rolled material.

Description

【発明の詳細な説明】 利用産業分野 この発明は、核燃料集合体輸送用容器、核燃料保管用ラ
ック及び使用済み核燃料保管用ラック等に用いられるＢ
　Ｏ，５ｗｔ％〜３．０ｗｔ％含有のＣｒ１５ｗｔ％〜
ｚｉｗｔ％、ＮＬ　７．０ｗｔ％〜ｉｅｗｔ％系オース
テナイトステンレス鋼の製造方法に係り、特に、熱間圧
延性の改善を目的としだＢ含有オーステナイトステンレ
ス鋼の製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION Field of Application This invention is applicable to containers for transporting nuclear fuel assemblies, racks for storing nuclear fuel, racks for storing spent nuclear fuel, etc.
Cr15wt%~ containing O, 5wt%~3.0wt%
ziwt%, NL 7.0wt% to iewt% type austenitic stainless steel, and particularly relates to a method of manufacturing B-containing austenitic stainless steel for the purpose of improving hot rolling properties.

背景技術 一般に、Ｂ含有のオーステナイトステンレス鋼は、含有
するＢの中性子吸収断面積が大きいことより、中性子の
制御材及び遮蔽材として用いられている。BACKGROUND ART In general, B-containing austenitic stainless steels are used as neutron control and shielding materials because the B they contain has a large neutron absorption cross section.

特に、高Ｂ含有オーステナイトステンレス鋼は、核燃料
集合体輸送用容器、核燃料保管用ラック及び使用済み核
燃料保管用ラック等に用いられているが、今日、該容器
やラックの小形化と低コスト化のために、素材である該
ステンレス鋼の薄肉化が要望されている。In particular, high B-containing austenitic stainless steel is used for containers for transporting nuclear fuel assemblies, racks for storing nuclear fuel, racks for storing spent nuclear fuel, etc., and today, there are efforts to make these containers and racks smaller and lower in cost. Therefore, there is a demand for thinner stainless steel material.

しかし、Ｂ含有のオーステナイトステンレス鋼は、Ｂ含
有量が多くなると、日がステンレス鋼に固溶せず、硼化
物が析出し、これが脆い性質を有するため、熱間加工時
に割れ易く、また一旦割れが生じると硼化物によって、
割れが伝播し、割れが少なく加工できる熱間加工温度領
域が狭く、難加工材となり、熱間圧延時に圧延材の表面
、特に冷却され易く引張力の掛る長手方向の縁部に、割
れやひび疵などが発生し易くなり、復工程での加工など
が不可能となって製品化できず、歩留が悪い問題があっ
た。However, when the B-containing austenitic stainless steel has a large B content, it does not dissolve solidly in the stainless steel and precipitates boride, which has brittle properties, making it easy to crack during hot working, and once it cracks. When , the boride causes
The cracks propagate, and the hot working temperature range that can be worked with fewer cracks is narrow, making the material difficult to work. During hot rolling, cracks and cracks can occur on the surface of the rolled material, especially at the longitudinal edges where it is easily cooled and where tensile force is applied. There was a problem that scratches were likely to occur, making it impossible to process in return processes, making it impossible to commercialize products, and resulting in poor yields.

このため、Ｂ含有のオーステナイトステンレス鋼の熱間
圧延性改善について、種々検討（特開昭５６−３８４１
８号、特開昭５４−６８４２号）されており、鋼材、Ｆ
ｅｈＬ合金あるいはＴｉ材の熱間圧延において、前記素
材の外周全面を薄鉄板で被包して熱間圧延したり、有孔
異種金属板で被包して熱間圧延する技術は知られている
が、これは酸化防止及び焼付き防止のためであり、本発
明鋼のごとき硼化物とオーステナイト相との２相よりな
る合金の難加工性を改善するのではなく、また、有孔異
種金属板を用いる場合は、素材と被包材間の空気抜き孔
のために逆に酸化が進行し、熱間圧延時に被包金属板が
素材より剥離する恐れがあった。For this reason, various studies were conducted on improving hot rolling properties of B-containing austenitic stainless steel (Japanese Patent Laid-Open No. 56-3841
No. 8, Japanese Patent Application Laid-Open No. 54-6842), steel materials, F
In hot rolling of ehL alloy or Ti material, techniques are known in which the entire outer periphery of the material is covered with a thin iron plate and hot rolled, or with a perforated dissimilar metal plate and hot rolled. However, this is for the purpose of preventing oxidation and seizure, and does not improve the difficult-to-work properties of an alloy consisting of two phases of boride and austenite, such as the steel of the present invention. When using a metal plate, oxidation progresses adversely due to the air vent holes between the raw material and the enveloping material, and there is a risk that the enveloping metal plate may separate from the material during hot rolling.

発明の目的 この発明は、Ｂ含有のオーステナイトステンレス鋼の熱
間加工性の改善を目的とし、熱間加工時に加工材の長手
方向縁部に割れやひび疵が発生するのを防止し、後続工
程の加工を容易にし、製品歩留の大幅な向上が・得られ
るＢ含有オーステナイトステンレス鋼の製造方法を目的
としている。Purpose of the Invention The present invention aims to improve the hot workability of B-containing austenitic stainless steel, to prevent cracks and cracks from occurring on the longitudinal edges of the workpiece during hot working, and to improve the performance of subsequent processes. The purpose of the present invention is to provide a method for producing B-containing austenitic stainless steel that facilitates processing and significantly improves product yield.

発明の構成 この発明は、 ３０．５ｗｔ％〜３．０ｗｔ％含有のＣｒ　１５ｗｔ％
〜２１ｗｔ％、ｘ＋　　ｙ、ｏｗｔ％〜ｉ　ｓｗｔ％系
オーステナイトステンレス鋼塊を、そのままかあるいは
、 長方形状に整形後、鋼塊の少なくとも４主面を鉄筒にて
密着包囲し、分塊圧延あるいは鍛造により圧着させたの
ち、 ９５０℃〜１２５０℃に加熱し、１パス当りの圧下率１
０％〜７０％で、少なくとも１回の熱間圧延を行なうこ
とを特徴とするＢ含有オーステナイトステンレス鋼の製
造方法である。Structure of the Invention This invention includes 15 wt% of Cr containing 30.5 wt% to 3.0 wt%.
~21 wt%, x + y, owt% ~ i swt% type austenitic stainless steel ingot, either as it is or after being shaped into a rectangular shape, tightly surrounding at least four main surfaces of the steel ingot with iron cylinders, and subjecting it to blooming or rolling. After being crimped by forging, it is heated to 950°C to 1250°C, and the rolling reduction rate per pass is 1.
This is a method for producing a B-containing austenitic stainless steel, characterized in that hot rolling is carried out at least once at a B-containing austenitic stainless steel of 0% to 70%.

さらに、詳述すれば、この発明は、 ａ、ｓ　ｏ、ｓｗｔ％〜３．０ｗｔ％含有のＣｒ１５ｗ
ｔ％〜２１ｗｔ％、Ｎ＝　ｙ、ｏｗｔ％〜１６ｗｔ％系
オーステナイトスチオ−ステナイト ステンレス鋼塊抜き用勾配のついた鋳塊の場合、そのま
まか、あるいは、軽鍛造して、勾配のない均一断面形状
からなる長方形に整形するか、あるいは連続鋳造による
スラブ鋳片またはビレット鋳片を所要寸法に切断整形し
、 Ｃ０得られた長方形状の整形鋼塊の少なくとも４主面、
すなわち、長手方向の両端面を除く上下面と両側面の４
主面あるいは全表面の黒皮を除去し、清浄化し、 ｄ、この４主面あるいは全表面を、炭素鋼あるいはステ
ンレス鋼からなるパイプや板による溶接組立体などの鉄
筒にて密着包囲し、 ｅ、上記鉄筒と整形鋼塊とを９５０℃〜１２５０℃にて
分塊圧延あるいは鍛造により圧着させたのち、ｆ、９５
０℃〜１２５０℃に加熱し、１パス当りの圧下率１０％
〜７０％で、少なくとも１回の熱間圧延を行なったのち
、 Ｑ、そのままか、あるいは溶体化処理を施し、必要に応
じて冷間圧延もしくはレベラーにより平坦度を矯正し、 ｈ、その後熱間圧延材の外周面最外層の鉄層を除去し、
必要に応じて冷間圧延もしくはレベラーにより平坦度を
矯正し、 熱間圧延時に圧延材の長手方向縁部に割れやひび疵のな
い品質良好な高８含有オーステナイトステンレス鋼を歩
留よく得る製造方法である。Further, in detail, the present invention provides Cr15w containing a, so, swt% to 3.0wt%.
t% ~ 21wt%, N = y, owt% ~ 16wt% austenitic sthio-stenite stainless steel For ingots with a slope for drawing ingots, use them as they are or lightly forge them to create a uniform cross section with no slope. At least four principal surfaces of the rectangular shaped steel ingot obtained by shaping it into a rectangular shape, or by cutting a slab slab or billet slab by continuous casting to the required dimensions,
In other words, 4 of the upper and lower surfaces and both side surfaces excluding both end surfaces in the longitudinal direction.
Remove black scale from the main surface or the entire surface, clean it, d. Closely surround the four main surfaces or the entire surface with an iron cylinder such as a welded assembly of carbon steel or stainless steel pipes or plates, e, after crimping the above-mentioned iron cylinder and shaped steel ingot by blooming rolling or forging at 950°C to 1250°C, f, 95
Heating from 0℃ to 1250℃, rolling reduction rate of 10% per pass
~ 70%, after hot rolling at least once, Q, as it is or solution treatment, and if necessary correcting the flatness by cold rolling or leveler, h, then hot rolling. Remove the outermost iron layer on the outer peripheral surface of the rolled material,
A manufacturing method for producing a high-quality high-8 content austenitic stainless steel with a high yield, with no cracks or cracks on the longitudinal edges of the rolled material during hot rolling, by correcting the flatness using cold rolling or a leveler as necessary. It is.

この発明において、上記ｄ、の鉄筒は、パイプ状や板材
による溶接組立体などが利用でき、整形鋼塊の４主面を
包囲するほか、全面を完全被包することも、鋼塊の温度
降下防止に有効であり、引張力軽減のためには４主面中
、特に、熱間圧延時の長手方向縁部にあたる両側面及び
縁部との密着が重要であり、上記の整形鋼塊を完全被包
したのち、鉄筒に穿孔して鉄筒と鋼塊との間を真空とな
してから封孔したほうが、整形鋼塊と鉄筒との溶着性が
向上するため好ましい。In this invention, the iron cylinder d above can be a pipe-shaped or welded assembly made of plate materials, and in addition to surrounding the four main surfaces of the shaped steel ingot, it can also be completely encapsulated over the entire surface, and It is effective in preventing dropping, and in order to reduce tensile force, it is important to have close contact with the edges and both sides, which are the longitudinal edges during hot rolling, among the four main surfaces. After complete encapsulation, it is preferable to drill a hole in the steel tube to create a vacuum between the steel tube and the steel ingot and then seal the hole, as this improves the weldability between the shaped steel ingot and the steel tube.

また、鉄筒の材質は、熱間変形抵抗及び熱膨張特性を一
致させるため、ステンレス鋼を用いるのもよいが、コス
ト面からは軟鋼が好ましく、鉄筒の厚みは、熱間圧延終
了まで残存する程度の厚みが必要で、好ましくは２ｍｍ
〜１０ｍｍ厚みである。In addition, stainless steel may be used as the material for the steel tube in order to match hot deformation resistance and thermal expansion characteristics, but from a cost perspective, mild steel is preferable, and the thickness of the steel tube should be such that it remains until the end of hot rolling. It is necessary to have a thickness of about 2 mm, preferably 2 mm.
~10mm thick.

発明の効果 この発明の製造方法により、熱間加工性が大幅に改善さ
れ、熱間加工時に加工材の長手方向縁部に割れやひび疵
のない品質良好な高８含有オーステナイト系ステンレス
鋼が得られるが、その理由は以下のとおりである。Effects of the Invention The production method of the present invention significantly improves hot workability and provides high-quality high-8 content austenitic stainless steel with no cracks or cracks on the longitudinal edges of the workpiece during hot working. The reason is as follows.

熱間加工時のロール接触あるいは冷却水及び周囲温度の
影響により、加工材の温度が低下するとともに加工時に
種々の引張力がかかり、上述の所謂耳ねれ等を生じるが
、この発明鋼は硼化物とオーステナイト相との２相から
なっており、温度低下や引張力の負荷により、割れやひ
び疵などが、一旦発生すると硼化物により次々と割れや
ひび疵が伝播進行し、製品化できな（なるため、特に初
期の割れやひび疵を発生させないことが重要であり、こ
の発明方法では素材表面に密着させた鉄筒によって上記
の温度低下が防止され、また、長手方向の縁部に掛りや
すい圧延時の引張力が、前記の鉄筒により緩和される。Due to roll contact during hot working or the influence of cooling water and ambient temperature, the temperature of the workpiece decreases and various tensile forces are applied during working, resulting in the so-called sagging described above. It consists of two phases: a boride phase and an austenite phase, and cracks and cracks occur due to temperature drop and tensile force loads.Once they occur, the boride causes cracks and cracks to propagate one after another, making it impossible to commercialize the product. (Thus, it is especially important to prevent initial cracks and cracks from occurring. In this invention method, the above-mentioned temperature drop is prevented by the steel tube that is tightly attached to the material surface, and The tensile force during rolling, which is easy to cause, is alleviated by the iron cylinder.

この発明の製造方法の効果は、熱間圧延のみならず、分
塊圧延あるいは鍛造時にも同様に有効であり、鍛造はハ
ンマー鍛造、プレス鍛造のいずれでも有効である。従っ
て、分塊圧延あるいは鍛造前に、鋼塊に鉄筒を密着包囲
し、熱間加工後に表面を切削し、表面を清浄化したのち
、再度、鉄筒にて密着包囲し、熱間圧延に供してもよい
が、歩留０作業性、鉄筒の密着性を考慮すると、鉄筒の
厚みを適切にして、分塊圧延おるいは鍛造前に密着包囲
し、これを除去することなく、熱間圧延時、熱間圧延後
の処理まで鉄筒により密着保護させた状態とするのが望
ましい。The effects of the manufacturing method of the present invention are not only effective during hot rolling but also during blooming rolling or forging, and the forging is effective whether it is hammer forging or press forging. Therefore, before blooming or forging, a steel tube is tightly surrounded by a steel ingot, and after hot working, the surface is cut and the surface is cleaned, and then the steel tube is tightly surrounded again and hot rolled. However, in consideration of workability with zero yield and adhesion of the iron cylinder, the thickness of the iron cylinder should be adjusted appropriately, and the iron cylinder should be tightly surrounded before blooming or forging, without removing it. During hot rolling, it is desirable that the steel tube be closely protected until the post-hot rolling treatment.

発明の限定理由 この発明においてオーステナイトステンレス鋼の成分限
定理由は、以下のとおりである。Reasons for Limiting the Invention The reasons for limiting the components of the austenitic stainless steel in this invention are as follows.

Ｂは、中性子の吸収効果を有するために含有するが、ｏ
、　ｓｗｔ％未満では、中性子吸収効果が少なく、制御
材、遮蔽材としての板厚が大きくなり、前述の容器やラ
ックが大型化しコスト高となるため好ましくなく、また
、３．０ｗｔ％を超える含有では材料の延び及び衝撃値
が著しく劣化して構造材として不適となるため、ｏ、　
５ｗｔ％〜３．０ｗｔ％の範囲とする。B is included to have a neutron absorption effect, but o
If the content is less than 3.0 wt%, the neutron absorption effect will be small, the thickness of the plate used as a control material or shielding material will become large, and the above-mentioned containers and racks will become larger and the cost will increase, which is undesirable. In this case, the elongation and impact value of the material deteriorate significantly, making it unsuitable as a structural material.
The range is 5 wt% to 3.0 wt%.

Ｃｒは、水系においてＮＬと共に耐食性を得るために含
有するが、１５ｗｔ％未満では、充分な耐食性が得られ
ず、Ｃｒの含有量の増加と共に耐食性は良好となるが、
２１ＶＦｔ％を超える含有ではその効果が飽和し、コス
ト面で好ましくないため、１５ｗｔ％〜２１ｗｔ％の範
囲とする。Cr is contained to obtain corrosion resistance together with NL in an aqueous system, but if it is less than 15 wt%, sufficient corrosion resistance cannot be obtained, and as the Cr content increases, corrosion resistance becomes better, but
If the content exceeds 21 VFt%, the effect is saturated and it is not preferable in terms of cost, so the content is set in the range of 15 wt% to 21 wt%.

Ｎｊは、水系においてＣｒと共に耐食性を得るために含
有するが、０．７ｗｔ％未満では、還元性雰囲気におけ
る充分な耐食性が得られず、また、１６ｗｔ％を超える
含有ではその効果が飽和し、コスト面で好ましくないた
め、０．７〜１６ｗｔ％の範囲とする。Nj is contained together with Cr in an aqueous system to obtain corrosion resistance, but if it is less than 0.7 wt%, sufficient corrosion resistance in a reducing atmosphere cannot be obtained, and if it is contained more than 16 wt%, the effect is saturated and the cost is reduced. Since it is not preferable in terms of the content, the content is set in the range of 0.7 to 16 wt%.

この発明において、好ましいＢ含有オーステナイトステ
ンレス鋼は、 Ｂ　０．５ｗｔ％〜３．０ｗｔ％、 Ｃ０，１２ｔｗｔ％以下、ＳＬ　１．ＯＷｊ％以下、＋
１１１　ｚ、ｏｗｔ％以下、 Ｐ　Ｏ，０５ｖｔ％以下、ｓｏ、ｏ３ｖｔ％以下、Ｃｒ
１５ｗｔ％〜２１ｗｔ％、ＮＬ　７．０〜１６ｗｔ％残
部実質的にＦａからなるオーステナイトステンレス鋼で
ある。In this invention, preferred B-containing austenitic stainless steel has the following properties: B 0.5wt% to 3.0wt%, C0.12twt% or less, SL 1. OWj% or less, +
111 z, owt% or less, P O, 05vt% or less, so, o3vt% or less, Cr
It is an austenitic stainless steel consisting of 15 wt% to 21 wt%, NL 7.0 to 16 wt%, and the remainder substantially consisting of Fa.

Ｃは、ｏ、１２ｗｔ％を超えると粒界に炭化物を生成し
易くなり、粒界腐蝕を起し易くなり好ましくないため、
０．１２ｔｗｔ％以下とする。If C exceeds 12 wt%, it tends to generate carbides at the grain boundaries, which is undesirable because it tends to cause intergranular corrosion.
The content shall be 0.12 twt% or less.

ＳＬは、耐酸化性及び溶接性の改善に有効であるが、１
．ｏｗｔ％を超える含有はその効果が飽和してコスト的
に好ましくないため、１．０Ｖ１ｔ％以下とする。SL is effective in improving oxidation resistance and weldability, but 1
．． If the content exceeds 1t%, the effect will be saturated and it is not preferable in terms of cost, so the content should be 1.0V1t% or less.

ｌ″ｔｎは、高温での耐酸化性が得られるが、２．０ｗ
ｔ％を超えると反って低下するため、２．０ｗｔ％％以
下とする。l″tn provides oxidation resistance at high temperatures, but 2.0w
If it exceeds t%, it will warp and deteriorate, so it should be 2.0wt% or less.

Ｐ　、Ｓは、応力腐蝕割れを発生し易くなるため、Ｐｏ
、０５ｗｔ％以下、ｓｏ、ｏ３ｗｔ％以下とする必要が
ある。P and S tend to cause stress corrosion cracking, so Po
, 05 wt% or less, so, o3 wt% or less.

水系ステンレス鋼において、残部は、Ｆｅと不可避的不
純物である。In water-based stainless steel, the remainder is Fe and unavoidable impurities.

また、この発明方法において、分塊圧延、鍛造並びに熱
間圧延の温度を９５０℃〜１２５０℃としたのは、９５
０℃未満では、成形鋼塊の変形抵抗が大きく、変形能が
低下し、われ疵などを発生するため好ましくなく、また
、１２５０℃を超えると、結品粒の粗大化が起り、われ
発生を惹起するためである。In addition, in the method of this invention, the temperature of blooming rolling, forging, and hot rolling is 950°C to 1250°C.
If the temperature is less than 0℃, the deformation resistance of the formed steel ingot will be large, the deformability will decrease, and cracks will occur, which is undesirable. This is to provoke.

また、１パス当りの圧下率を１０％〜７０％としたのは
、１０％未満では硼化物の充分な微細分散化を計ること
ができず、また、７０％を超えると加工度が大きくなり
すぎ、われまたはひび疵が発生し易くなるためである。In addition, the rolling reduction rate per pass was set at 10% to 70% because if it is less than 10%, sufficient fine dispersion of boride cannot be achieved, and if it exceeds 70%, the degree of processing becomes large. This is because scratches, cracks, and cracks are more likely to occur.

実施例 叉塵炎ユ ８１．８ｗｔ％、ｃ　　ｏ、ｏｏ５ｗｔ％、ＳＬ　Ｏ，
４１ｗｔ％、？　１．４９　ｗｔ％、Ｃｒ　１８．５ｗ
ｔ％、ＮＬｌｌ、４ｗｔ％ｐ　０．０１０ｗｔ％、Ｓ　
０．００４ｗｔ％、残部実質的にＦｅ からなるオーステナイトステンレス鋼を、上辺２７０ｍ
ｍＸ　１５５ｍｍ下辺２６５ｍｍＸ　１１５ｍｍ高さ５
６０ｍｍ寸　法の１６０Ｋｇの平板状鋼塊となし、手入
により鋳肌表面を除去して清浄化し、押湯部切断後、長
手方向の上下面と両側面の４主面に、厚み７ｍｍの　０
０．１５％の鋼板の溶接組立体よりなる軟鋼筒にて密着
包囲すると共に、長手両端に、該軟鋼筒との間をＣｒ　
１９．８ｗｔ％、　ＮＩＯ，０ｗｔ％よりなるオーステ
ナイトステンレス鋼にて溶接対しをし、これをプレス鍛
造により、１０５０℃で、厚み６５ｍｍＸ幅２８０ｍｍ
Ｘ長さ１２３５ｍｍに仕上鍛造し、軟鋼筒を圧着させた
。Example dust flame 81.8wt%, co, oo5wt%, SLO,
41wt%? 1.49 wt%, Cr 18.5w
t%, NLll, 4wt%p 0.010wt%, S
Austenitic stainless steel consisting of 0.004wt%, the remainder being substantially Fe, with an upper side of 270m.
mX 155mm Bottom side 265mmX 115mm Height 5
A 160 kg flat steel ingot with a size of 60 mm was prepared, the cast surface was removed and cleaned, and after the feeder section was cut, a 7 mm thick steel ingot with a thickness of 7 mm was placed on the four main surfaces of the top, bottom and both sides in the longitudinal direction.
It is tightly surrounded by a mild steel tube made of a welded assembly of 0.15% steel plates, and Cr is installed between the longitudinal ends and the mild steel tube.
Welded austenitic stainless steel consisting of 19.8 wt% and NIO, 0 wt%, and press-forged this at 1050°C to a thickness of 65 mm x width of 280 mm.
Finish forging was performed to a length of 1235 mm, and a mild steel cylinder was crimped.

その後、１２２０℃に加熱し、１パス当りの圧下率５４
％、　４０％、３３％、３３％の熱間圧延を行ない、板
厚＆ｍｍＸ幅３２０ｍｍＸ長さ８７８０ｍｍ寸法の板材
となした。After that, it was heated to 1220°C, and the rolling reduction rate per pass was 54.
%, 40%, 33%, and 33% hot rolling to obtain a plate with dimensions of plate thickness &mm x width 320mm x length 8780mm.

熱間圧延後に、ｉ　ｏｏｏ℃、０．５時間の熱処理を行
ない、水冷し、板材の外表面の軟鉄層部分を切削除去し
、長手２分割し、レベラーにより平坦度を矯正し、最終
仕上寸法として、板厚７ｍｍＸ幅３００ｍｍＸ長ざ４３
００ｗｕｎ寸法の板材となした。After hot rolling, heat treatment is performed at 100°C for 0.5 hours, water-cooled, the soft iron layer on the outer surface of the plate is removed, the length is divided into two parts, the flatness is corrected with a leveler, and the final finished dimensions are determined. As, plate thickness 7mm x width 300mm x length 43
It was made into a plate material with a size of 00wun.

また、比較例として、上記組成のオーステナイトステン
レス鋼をそのまま熱間圧延し、同様の板厚７ｍｍＸ幅３
００ｍｍＸ長ざ４３００ｍｍ寸法の最終仕上寸法となし
た。In addition, as a comparative example, an austenitic stainless steel with the above composition was hot-rolled as it was, and a similar plate thickness of 7 mm x width of 3 mm was prepared.
The final finished dimensions were 00mm x length 4300mm.

得られた２種のオーステナイトステンレス熱間圧延材の
加工における各々の加熱回数と耳割れ状況及び製品歩留
（最終製品／熱間圧延材Ｘ　１００％）を調べ、第１表
にその結果を示す。The number of heating times, edge cracking situation, and product yield (final product/hot rolled material .

大展望２ Ｂ　２．０ｗｔ％、ｃｏ、ｏ３ｗｔ％、ＳＬ　Ｏ，５３
ｗｔ％、Ｉｎｎ　１．４５　ｗｔ％、ｃｒｔｙ、８ｗｔ
％、Ｎｉ１２．１０　ｗｔ％ｐ　ｏ、ｏｉ１ｗｔ％、ｓ
　ｏ、ｏｏ６ｗｔ％、残部実質的にＦｅ からなるオーステナイトステンレス鋼を、勾配比３．４
を有する１８０Ｋｇの平板状鋼塊となし、これを軽鍛造
して、黒皮を除去し、厚み１１０ｍｍＸ幅２５０ｍｍＸ
長さ７７０ｍｍ寸法の均一断面を有する長方形状に整形
手入後、表面を清浄化し、これを、厚み８岨、外径１２
６ｍｍＸ　２６６ｍｍ、内径１１０ｍｍＸ　２５０ｍｍ
。Great outlook 2 B 2.0wt%, co, o3wt%, SL O,53
wt%, Inn 1.45 wt%, crty, 8wt
%, Ni12.10 wt%po, oi1wt%, s
Austenitic stainless steel consisting of 6 wt% o, oo, and the remainder substantially Fe, with a gradient ratio of 3.4
A 180Kg flat steel ingot with
After shaping into a rectangular shape with a uniform cross section of 770 mm in length, the surface was cleaned and this was shaped into a rectangular shape with a thickness of 8 mm and an outer diameter of 12 mm.
6mm x 266mm, inner diameter 110mm x 250mm
.

長さ７７０ｍｍ寸法のＣＯ，１８％の軟鋼筒に装入し、
長手両端につき、該軟！ｊ！筒との間をＣｒ１９ｗｔ％
、Ｎｉ９、５ｗｔ％よりなるオーステナイトステンレス
鋼にて溶接対しをし、これをハンマー鍛造により、１ｉ
ｏｏ℃で、厚み７０ｍｍＸ幅２７０ｍｍＸ長ざ１３６５
ｍｍに仕上鍛造し、軟鋼筒を圧着させた。Charged into a CO, 18% mild steel tube with a length of 770 mm,
At both longitudinal ends, the soft! j! Cr19wt% between the tube and the tube
, welded with austenitic stainless steel consisting of 9.5 wt% Ni, and hammer-forged it into a
At oo℃, thickness 70mm x width 270mm x length 1365
It was finish forged to a diameter of mm and a mild steel cylinder was crimped.

その後、１１８０℃に加熱し、１パス当りの圧下率３４
％の熱間圧延を行ない、２パスで板厚３０ｍｍＸ幅２７
５ｍｍＸ長さ３７２５ｍｍ寸法となし、１２１０℃に再
加熱し、１パス当りの圧下率４３％、４１％及び３０％
の３バスの熱間圧延を行ない、板厚７ｍｍＸ幅２８５ｍ
ｍＸ長さ１２９００ｍｍ寸法の板材となした。After that, it was heated to 1180℃, and the rolling reduction rate per pass was 34
% hot rolling, and in 2 passes, the plate thickness was 30 mm x width was 27 mm.
Dimensions: 5mm x length 3725mm, reheated to 1210°C, reduction rate per pass: 43%, 41%, and 30%.
Hot rolling was carried out in 3 buses, and the plate thickness was 7mm x width was 285m.
It was made into a plate material with dimensions of m x length 12900 mm.

熱間圧延後に長手方向に３分割し、１０５０’Ｃ，１時
間の熱処理を行ない、水冷後レベラーにより平坦度を矯
正し、板材の外表面の軟鉄層部分を切削除去し、最終仕
上寸法として、板厚ＢｍｍＸ幅２７０ｍｍＸ長さ４３０
０ｍｍ寸法の板材となした。After hot rolling, it was divided into three parts in the longitudinal direction, heat treated at 1050'C for 1 hour, and after water cooling, the flatness was corrected using a leveler, and the soft iron layer on the outer surface of the board was removed, and the final finished dimensions were as follows. Plate thickness Bmm x width 270mm x length 430
It was made into a plate material with a size of 0 mm.

また、比較例として、上記組成のオーステナイトステン
レス鋼をそのまま鍛造及び熱間圧延し、同様の最終仕上
寸法となした。Further, as a comparative example, austenitic stainless steel having the above composition was directly forged and hot rolled to have the same final dimensions.

得られた２種のオーステナイトステンレス熱間圧延材の
架構における各々の加熱回数と、耳割れ状況及び製品歩
留（最終製品／鋼塊ｘ　１００％）を調べ、第２表にそ
の結果を示す。The number of heating times, edge cracking situation, and product yield (final product/steel ingot x 100%) of the two types of hot-rolled austenitic stainless steel frames obtained were investigated, and the results are shown in Table 2.

第１表及び第２表の結果より明らかな如く、この発明の
製造方法によって、難加工性である高Ｂ含有オーステナ
イトステンレス鋼の熱間加工性が大幅に改善され、製品
歩留の著しい向上が認められ、核燃料保管用ラックや使
用済み核燃料保管用ラック等の小形化と低コスト化に有
利な薄肉化が容易なことが分る。As is clear from the results in Tables 1 and 2, the production method of the present invention significantly improves the hot workability of high B-containing austenitic stainless steel, which is difficult to form, and significantly improves the product yield. It can be seen that it is easy to make nuclear fuel storage racks, spent nuclear fuel storage racks, etc. thinner, which is advantageous for downsizing and cost reduction.

特許出願人　住友特殊金属株式会社 出願代理人　押　１）良　久腸卿 自発手続ン甫正書 昭和６０年１０月２日 １、事件の表示 昭和６０年　特許願　第４１４６３号 ２、発明の名称 Ｂ含有オーステナイトステンレス鋼の製造方法３、補正
をする者 事件との関係　　　　出願人 ４、代理人 ５、補正の対象　　　。Patent Applicant: Sumitomo Special Metals Co., Ltd. Application Agent: 1) Ryo Kucho-kyou Voluntary Procedure N Hoshosho October 2, 1985 1, Indication of the Case 1985 Patent Application No. 41463 2, Name of the Invention B Manufacturing method for austenite-containing stainless steel 3, relationship with the case of the person making the amendment Applicant 4, attorney 5, subject of amendment.

１、明細書第３頁６行から１８行の 「このため、Ｂ含有のオーステナイトステンレス鋼の熱
間圧延性改善について、種々検討（特開昭５６−３８４
１８号、特開昭５４−６８４２号）されており、鋼材、
ＦａＮＬ合金あるいはｎ材の熱間圧延において、前記素
材の外周全面を薄鉄板で被包して熱間圧延したり、有孔
異種金属板で被包して熱間圧延する技術は知られている
が、これは酸化防止及び焼付き防止のためであり、本発
明鋼のごとき硼化物とオーステナイト相との２相よりな
る合金の難加工性を改善するのではなく、また、有孔異
種金属板を用いる場合は、素材と被包材間の空気抜き孔
のために逆に酸化が進行し、熱間圧延時に被包金属板が
素材より剥離する恐れがあった。」を次のように補正す
る。1. On page 3 of the specification, lines 6 to 18, ``Therefore, various studies have been conducted regarding the improvement of hot rolling properties of B-containing austenitic stainless steel (Japanese Unexamined Patent Publication No. 56-384
No. 18, JP-A No. 54-6842), steel materials,
In the hot rolling of FaNL alloy or N material, there are known techniques in which the entire outer periphery of the material is covered with a thin iron plate and hot rolled, or with a perforated dissimilar metal plate and hot rolled. However, this is for the purpose of preventing oxidation and seizure, and does not improve the difficult-to-work properties of an alloy consisting of two phases of boride and austenite, such as the steel of the present invention. When using a metal plate, oxidation progresses adversely due to the air vent holes between the raw material and the enveloping material, and there is a risk that the enveloping metal plate may separate from the material during hot rolling. ” is corrected as follows.

「このため、Ｂ含有のオーステナイトステンレス鋼の熱
間圧延性改善について、種々検討されており、鋼材、Ｆ
ｓＮＬ合金あるいはＴＬ材の熱間圧延において、前記素
材の外周全面を薄鉄板で被包して熱間圧延したり（特開
昭５６−３８４１８号）、有孔異種金属板で被包して熱
間圧延する技術（特開昭５４−６８４２号）が知られて
いるが、これは酸化防止及び焼付き防止のためであり、
本発明鋼のごとき硼化物とオーステナイト相との２相よ
りなる合金の難加工性を改善するのではなく、また、有
孔異種金属板を用いる場合は、素材と被包材間の空気抜
き孔のために逆に酸化が進行し、熱間圧延時に被包金属
板が素材より剥離する恐れがあった。」２、明細書第９
頁１１行から１５行の Ｉｎは、水系においてＣｒと共に耐食性を得るために含
有するが、０．７ｗｔ％未満では、還元性雰囲気におけ
る充分な耐食性が得られず、また、１６ｗｔ％を超える
含有ではその効果が飽和し、コスト面で好ましくないた
め、０．７〜１６ｗｔ％の範囲とする。Ｊを次のように
補正する。``For this reason, various studies have been conducted to improve hot rolling properties of B-containing austenitic stainless steels, and steel materials, F
In hot rolling of sNL alloy or TL material, the entire outer periphery of the material is covered with a thin iron plate and hot rolled (Japanese Patent Application Laid-Open No. 56-38418), or covered with a perforated dissimilar metal plate and heated. A technique of inter-rolling (Japanese Unexamined Patent Publication No. 54-6842) is known, but this is for the purpose of preventing oxidation and seizure.
Rather than improving the difficult workability of alloys consisting of two phases of boride and austenite, such as the steel of the present invention, when using a perforated dissimilar metal plate, it is necessary to As a result, oxidation progressed, and there was a risk that the encapsulated metal plate would separate from the material during hot rolling. ” 2, Specification No. 9
In, as shown in lines 11 to 15 on page 1, is contained in order to obtain corrosion resistance together with Cr in an aqueous system, but if it is less than 0.7 wt%, sufficient corrosion resistance cannot be obtained in a reducing atmosphere, and if the content exceeds 16 wt%, In Since the effect reaches saturation and is not desirable from a cost perspective, the content is set in the range of 0.7 to 16 wt%. Correct J as follows.

「ＮＬは、水系においてＣｒと共に耐食性を得るために
含有するが、７．０ｗｔ％未満では、還元性雰囲気にお
ける充分な耐食性が得られず、また、１６ｗｔ％を超え
る含有ではその効果が飽和し、コスト面で好ましくない
ため、７．０〜１６ｗｔ％の範囲とする。Ｊ３、明細書
第１３頁４行の 「（最終製品／熱間圧延材Ｘ　１００％）」を「（最終
製品／鋼塊×１００％）」と補正する。``NL is contained together with Cr in an aqueous system to obtain corrosion resistance, but if it is less than 7.0 wt%, sufficient corrosion resistance in a reducing atmosphere cannot be obtained, and if the content exceeds 16 wt%, the effect is saturated. Since it is unfavorable in terms of cost, it is set in the range of 7.0 to 16 wt%.J3, "(Final product/Hot rolled material ×100%)”.

４、明細書簡１５頁６行目の「架構」を「加工」と補正
する。4. "Frame" in line 6 on page 15 of the specification letter is corrected to "processing."

Claims (1)

【特許請求の範囲】[Claims] Ｂ　０．５ｗｔ％〜３．０ｗｔ％含有のＣｒ　１５ｗｔ
％〜２１ｗｔ％、Ｎｉ　７．０ｗｔ％〜１６ｗｔ％系オ
ーステナイトステンレス鋼塊を、そのままかあるいは、
長方形状に整形後、鋼塊の少なくとも４主面を鉄筒にて
密着包囲し、分塊圧延あるいは鍛造により圧着させたの
ち、９５０℃〜１２５０℃に加熱し、１バス当りの圧下
率１０％〜７０％で、少なくとも１回の熱間圧延を行な
うことを特徴とするＢ含有オーステナイトステンレス鋼
の製造方法。Cr 15wt containing B 0.5wt% to 3.0wt%
% ~ 21 wt%, Ni 7.0 wt% ~ 16 wt% type austenitic stainless steel ingot, as it is or
After shaping the steel ingot into a rectangular shape, at least four main surfaces of the steel ingot are closely surrounded by iron cylinders, and after being crimped by blooming rolling or forging, the steel ingot is heated to 950°C to 1250°C, with a rolling reduction rate of 10% per bath. 70% B-containing austenitic stainless steel, the method comprising hot rolling at least once.