JPH09291344A - Low hardness martensitic stainless steel - Google Patents
Low hardness martensitic stainless steelInfo
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- JPH09291344A JPH09291344A JP12712996A JP12712996A JPH09291344A JP H09291344 A JPH09291344 A JP H09291344A JP 12712996 A JP12712996 A JP 12712996A JP 12712996 A JP12712996 A JP 12712996A JP H09291344 A JPH09291344 A JP H09291344A
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- stainless steel
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、低硬度のマルテン
サイト系ステンレス鋼に関するものである。TECHNICAL FIELD The present invention relates to a low hardness martensitic stainless steel.
【０００２】[0002]
【従来の技術】マルテンサイト系ステンレス鋼は、ＡＩ
ＳＩ４２０鋼に代表されるように、強度、耐食性に優れ
比較的安価であることから１９８０年頃より刃物、ダイ
ス、機械部品、油井管などとして幅広く適用されてきて
いる。最近、４２０鋼より優れた耐食性を有する、特開
平３−１２０３３７号公報などに見られるような、低Ｃ
及びＮｉ−Ｍｏ添加鋼、あるいは特開平２−２４７３６
０号公報などに見られるような、低Ｃ及びＣｕ−Ｎｉ−
Ｍｏ添加鋼といった鋼種（いわゆるModified １３Ｃｒ
鋼と称される鋼種）が開発されてきている。2. Description of the Related Art Martensitic stainless steel has been developed using AI.
Since it has excellent strength and corrosion resistance and is relatively inexpensive, as represented by SI420 steel, it has been widely applied since 1980 as a cutting tool, a die, a machine part, an oil country tubular good, and the like. Recently, low C, which is superior to 420 steel in corrosion resistance, as seen in JP-A-3-120337.
And Ni-Mo added steel, or JP-A-2-24736.
Low C and Cu-Ni- as seen in Japanese Patent No.
Steel types such as Mo-added steel (so-called Modified 13Cr
Steel type called steel) has been developed.
【０００３】[0003]
【発明が解決しようとする課題】かかる鋼はその製造工
程において、鋳造ままあるいは分塊圧延後のスラブ、ブ
ルーム、ビレットを所要の長さに切断する工程が必須で
あるが、上記Modified１３Ｃｒ鋼は焼入れマルテンサイ
ト組織での硬さがビッカーズ硬さで３７０程度と硬いた
めこのままでは通常の冷間鋸断工具で切断できず、軟化
焼鈍を程してビッカーズ硬さで２７０程度まで軟化させ
た後切断せざるをえず、コスト高となる問題があった。
そこで、本発明は軟化焼鈍工程省略を可能とする鋸断性
に優れた低硬度マルテンサイト系ステンレス鋼を提供す
ることを目的とする。In the manufacturing process of such steel, it is essential to cut the slab, bloom and billet as cast or after slabbing into the required length. However, the above Modified 13Cr steel is hardened. Since the hardness of the martensite structure is as hard as Vickers hardness of about 370, it cannot be cut with a normal cold sawing tool as it is, and after softening annealing to a Vickers hardness of about 270, cutting is performed. There was no choice but to raise the cost.
Therefore, an object of the present invention is to provide a low-hardness martensitic stainless steel having excellent sawing property that enables the softening and annealing step to be omitted.
【０００４】[0004]
【課題を解決するための手段】本発明者らは、合金添加
量の異なる種々の素材に対して焼入れマルテンサイト組
織でのビッカーズ硬さを調査するとともに、通常の冷間
鋸断工具で切断できる材料の限界硬さを求めた。その結
果、焼入れマルテンサイト組織での硬さをビッカーズ硬
さで３３０程度に低下させれば軟化焼鈍工程が省略で
き、その分コストを低廉化できることを知見した。ま
た、各添加元素が焼入れマルテンサイト組織でのビッカ
ーズ硬さに及ぼす影響を解明し、Ｃeq＝Ｃ＋Ｎ＋０．０
１７Ｎｉ＋０．０１５Ｍｏ≦０．１５を満足すれば焼入
れマルテンサイト組織での硬さをビッカーズ硬さで３３
０以下にできることを見いだした。さらに、焼入れマル
テンサイト組織での硬さをビッカーズ硬さで３００以下
に低下させれば冷間鋸断工具のチッピングは起こらず、
工具の長寿命化が可能であることを知見し、Ｃeq≦０．
１３を満足すれば焼入れマルテンサイト組織での硬さを
ビッカーズ硬さ３００以下にできることを見いだした。The present inventors investigated the Vickers hardness of a hardened martensite structure for various materials having different alloy addition amounts, and were able to cut with a normal cold sawing tool. The critical hardness of the material was determined. As a result, it has been found that if the hardness in the quenched martensite structure is reduced to about Vickers hardness of about 330, the softening and annealing step can be omitted, and the cost can be reduced accordingly. Further, the effect of each additive element on the Vickers hardness in the quenched martensite structure was clarified, and C eq = C + N + 0.0
If 17Ni + 0.015Mo ≦ 0.15 is satisfied, the hardness in the quenched martensite structure is 33 in Vickers hardness.
I found that I can make it less than 0. Further, if the hardness in the hardened martensite structure is reduced to 300 or less in Vickers hardness, chipping of the cold sawing tool does not occur,
It was found that the tool life can be extended, and C eq ≦ 0.
It was found that the hardness of the hardened martensite structure can be reduced to Vickers hardness of 300 or less if 13 is satisfied.
【０００５】一方、重量％でＮの添加量の３．４倍以上
のＴｉを加えた場合には、凝固過程でＴｉＮが析出する
ので固溶Ｎ量が減少するためＮの影響は無視でき、
Ｃeq’＝Ｃ＋０．０１７Ｎｉ＋０．０１５Ｍｏ≦０．１
５を満足すれば焼入れマルテンサイト組織での硬さをビ
ッカーズ硬さ３３０以下にできることを見いだした。さ
らに、重量％でＮの添加量の３．４倍以上のＴｉを加え
た場合には、Ｃeq’≦０．１３を満足すれば焼入れマル
テンサイト組織での硬さをビッカーズ硬さ３００以下に
できることを見いだした。On the other hand, when Ti is added in an amount of 3.4 times as much as the amount of N added by weight%, TiN is precipitated during the solidification process and the amount of solute N is reduced, so that the effect of N can be ignored.
C eq '= C + 0.017Ni + 0.015Mo ≦ 0.1
It was found that the hardness of the hardened martensite structure can be reduced to Vickers hardness of 330 or less if 5 is satisfied. Furthermore, when Ti is added in an amount of 3.4 times the amount of N added by weight%, the hardness in the quenched martensite structure is reduced to Vickers hardness of 300 or less if C eq '≦ 0.13 is satisfied. I found what I could do.
【０００６】本発明はこのような知見に基づいて構成し
たものであり、その要旨は、（１）重量％で、 Ｃ ：０．０２５％以下、 Ｓｉ：０．５％以下、 Ｍｎ：１．５％以下、 Ｐ ：０．０３％以下、 Ｓ ：０．０１％以下、 Ｃｒ：１１〜１７％、 Ｎｉ：４．５〜７．０％、 Ａｌ：０．０６％以下、 Ｎ ：０．０２５％以下、 Ｍｏ：１．０〜３．０％ を含有し、さらに必要に応じて、 Ｃａ：０．００１〜０．０２％、 Ｃｕ：０．５〜３．０％、 の１種または２種を含有し、なおかつ、 Ｃeq＝Ｃ＋Ｎ＋０．０１７Ｎｉ＋０．０１５Ｍｏ≦０．
１５ を満足し、残部がＦｅ及び不可避的不純物からなる低硬
度マルテンサイト系ステンレス鋼。および、（２）重量
％で、 Ｃ ：０．００５％以下、 Ｓｉ：０．５％以下、 Ｍｎ：１．５％以下、 Ｐ ：０．０３％以下、 Ｓ ：０．０１％以下、 Ｃｒ：１１〜１７％、 Ｎｉ：４．５〜７．０％、 Ａｌ：０．０６％以下、 Ｎ ：０．００５％以下、 Ｍｏ：１．０〜３．０％ を含有し、さらに必要に応じて、 Ｃａ：０．００１〜０．０２％、 Ｃｕ：０．５〜３．０％ の１種または２種を含有し、なおかつ、 Ｃeq＝Ｃ＋Ｎ＋０．０１７Ｎｉ＋０．０１５Ｍｏ≦０．
１３ を満足し、残部がＦｅ及び不可避的不純物からなる低硬
度マルテンサイト系ステンレス鋼。さらに、（３）重量
％で、 Ｃ ：０．０２５％以下、 Ｓｉ：０．５％以下、 Ｍｎ：１．５％以下、 Ｐ ：０．０３％以下、 Ｓ ：０．０１％以下、 Ｃｒ：１１〜１７％、 Ｎｉ：４．５〜７．０％、 Ａｌ：０．０６％以下、 Ｎ ：０．０２５％以下、 Ｍｏ：１．０〜３．０％、 Ｔｉ：３．４Ｎ〜０．３％ を含有し、さらに必要に応じて、 Ｃａ：０．００１〜０．０２％、 Ｃｕ：０．５〜３．０％ の１種または２種を含有し、なおかつ、 Ｃeq’＝Ｃ＋０．０１７Ｎｉ＋０．０１５Ｍｏ≦０．１
５ を満足し、残部がＦｅ及び不可避的不純物からなる低硬
度マルテンサイト系ステンレス鋼であり、（４）重量％
で、 Ｃ ：０．００５％以下、 Ｓｉ：０．５％以下、 Ｍｎ：１．５％以下、 Ｐ ：０．０３％以下、 Ｓ ：０．０１％以下、 Ｃｒ：１１〜１７％、 Ｎｉ：４．５〜７．０％、 Ａｌ：０．０６％以下、 Ｎ ：０．０２５％以下、 Ｍｏ：１．０〜３．０％、 Ｔｉ：３．４Ｎ〜０．３％ を含有し、さらに必要に応じて、 Ｃａ：０．００１〜０．０２％、 Ｃｕ：０．５〜３．０％ の１種または２種を含有し、なおかつ、 Ｃeq’＝Ｃ＋０．０１７Ｎｉ＋０．０１５Ｍｏ≦０．１
３ を満足し、残部がＦｅ及び不可避的不純物からなる低硬
度マルテンサイト系ステンレス鋼である。The present invention is constructed on the basis of such knowledge, and the gist thereof is (1)% by weight, C: 0.025% or less, Si: 0.5% or less, Mn: 1. 5% or less, P: 0.03% or less, S: 0.01% or less, Cr: 11 to 17%, Ni: 4.5 to 7.0%, Al: 0.06% or less, N: 0. 0: 25% or less, Mo: 1.0 to 3.0% is contained, and further, if necessary, Ca: 0.001 to 0.02%, Cu: 0.5 to 3.0%, or one of 2 kinds, and C eq = C + N + 0.017Ni + 0.015Mo ≦ 0.
A low-hardness martensitic stainless steel that satisfies 15 and the balance consists of Fe and inevitable impurities. And (2) wt%, C: 0.005% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.01% or less, Cr : 11 to 17%, Ni: 4.5 to 7.0%, Al: 0.06% or less, N: 0.005% or less, Mo: 1.0 to 3.0%, and further necessary Accordingly, it contains one or two of Ca: 0.001 to 0.02% and Cu: 0.5 to 3.0%, and C eq = C + N + 0.017Ni + 0.015Mo ≦ 0.
A low-hardness martensitic stainless steel that satisfies 13 and the balance consists of Fe and inevitable impurities. Further, in (3)% by weight, C: 0.025% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.01% or less, Cr : 11 to 17%, Ni: 4.5 to 7.0%, Al: 0.06% or less, N: 0.025% or less, Mo: 1.0 to 3.0%, Ti: 3.4N or more. 0.3% and, if necessary, 1 or 2 kinds of Ca: 0.001 to 0.02% and Cu: 0.5 to 3.0%, and C eq '. = C + 0.017Ni + 0.015Mo ≦ 0.1
5 is a low hardness martensitic stainless steel with the balance being Fe and inevitable impurities, and (4) wt%
Then, C: 0.005% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.01% or less, Cr: 11 to 17%, Ni : 4.5 to 7.0%, Al: 0.06% or less, N: 0.025% or less, Mo: 1.0 to 3.0%, Ti: 3.4N to 0.3% If necessary, Ca: 0.001 to 0.02%, Cu: 0.5 to 3.0%, one or two, and C eq ′ = C + 0.017Ni + 0.015Mo ≦ 0.1
3 is a low hardness martensitic stainless steel with the balance being Fe and inevitable impurities.
【０００７】[0007]
【発明の実施の形態】以下、本発明について詳細に説明
する。本発明におけるマルテンサイト系ステンレス鋼の
成分限定理由は以下の通りである。 Ｃ：ＣはＣｒ炭化物などを形成し耐食性を劣化させる元
素である。また、マルテンサイトの硬さを増大させる。
このため上限を０．０２５％とした。特に、０．００５
％以下にすれば被切削性がさらによくなる。下限は低い
ほど良い。 Ｓｉ：Ｓｉは製鋼工程において脱炭剤として添加される
ものである。０．５％を超えて含有されると靱性が劣化
することから、上限を０．５％とした。BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The reasons for limiting the components of the martensitic stainless steel in the present invention are as follows. C: C is an element that forms a Cr carbide or the like and deteriorates corrosion resistance. It also increases the hardness of martensite.
Therefore, the upper limit is set to 0.025%. In particular, 0.005
If it is less than%, the machinability is further improved. The lower the lower limit, the better. Si: Si is added as a decarburizing agent in the steelmaking process. If the content exceeds 0.5%, the toughness deteriorates, so the upper limit was made 0.5%.
【０００８】Ｍｎ：Ｍｎはオーステナイト安定化元素で
あり、熱間加工時にδ相の析出を抑制することにより圧
延疵防止に有効であるが、１．５％を超えて添加すると
粒界強度を低下させ靱性が劣化するので１．５％を上限
とした。 Ｐ：Ｐは粒界に偏析して粒界強度を低下させ、靱性を劣
化させる不純物元素であり、可及的低レベルが望ましい
が、現状製錬技術の到達可能レベルとコストを考慮し
て、上限を０．０３％とした。 Ｓ：Ｓは硫化物系の介在物を形成し、熱間加工性を劣化
させる不純物元素であり、可及的低レベルが望ましい
が、現状製錬技術の到達可能レベルとコストを考慮し
て、上限を０．０１％とした。Mn: Mn is an austenite stabilizing element and is effective in preventing rolling flaws by suppressing precipitation of the δ phase during hot working, but if added in excess of 1.5%, the grain boundary strength decreases. As a result, the toughness deteriorates, so 1.5% was made the upper limit. P: P is an impurity element that segregates at the grain boundaries to lower the grain boundary strength and deteriorates the toughness, and the lowest possible level is desirable. However, considering the reachable level and cost of the current smelting technology, The upper limit was 0.03%. S: S is an impurity element that forms sulfide-based inclusions and deteriorates hot workability, and the lowest possible level is desirable, but considering the reachable level and cost of the current smelting technology, The upper limit was 0.01%.
【０００９】Ｃｒ：Ｃｒは耐食性向上の基本元素であ
り、十分な耐食性を得るには１１％以上の添加が必要で
あるが、フェライト安定化元素でもあり、多すぎると熱
間加工時にδ相が析出して熱間加工性を劣化するため、
上限を１７％とした。 Ｎｉ：Ｎｉは耐腐食性向上及び靱性向上に有効である。
また、オーステナイト安定化元素であり、圧延疵につな
がるδ相の生成を抑止する。これらの効果は添加量４．
５％以下では小さいため、下限を４．５％とした。ま
た、７％を超えて添加しても効果が飽和するとともにＡ
ｃ1 変態点を低下させ強度調質を困難にすることから、
最適添加範囲を１．５〜７％とした。ただし、４．５％
を超えて添加すると焼き入れままのマルテンサイトの硬
さを増加させるため、添加量は良好な熱間加工性維持の
ための必要最小量にするのが望ましい。Cr: Cr is a basic element for improving the corrosion resistance, and it is necessary to add 11% or more to obtain sufficient corrosion resistance, but it is also a ferrite stabilizing element, and if it is too much, the δ phase is formed during hot working. Since it precipitates and deteriorates the hot workability,
The upper limit was set to 17%. Ni: Ni is effective for improving corrosion resistance and toughness.
Further, it is an austenite stabilizing element and suppresses the formation of the δ phase which leads to rolling defects. These effects have the added amount of 4.
Since it is small at 5% or less, the lower limit is set to 4.5%. In addition, even if it exceeds 7%, the effect is saturated and
c 1 lowering the transformation point and making strength tempering difficult,
The optimum addition range was 1.5 to 7%. However, 4.5%
If it is added in excess, the hardness of as-quenched martensite increases, so it is desirable that the addition amount be the minimum amount necessary for maintaining good hot workability.
【００１０】Ａｌ：Ａｌは脱酸の目的で添加されるが、
０．０６％以下の添加で十分な効果が得られ、また０．
０６％を超えて添加すると靱性が低下するため、上限を
０．０６％とした。 Ｎ：ＮはＭｎ、Ｍｏと同様に強力なオーステナイト安定
化元素であり、圧延疵防止に有効であるが、Ｃと同様に
マルテンサイトの硬さを増大させる。このため上限を
０．０２５％とした。特に、０．００５％以下にすれば
被切削性がさらに良くなる。下限は低いほど良い。 Ｍｏ：Ｍｏは耐孔食性、耐応力腐食割れ性を向上させる
のに必須の元素である。これらの効果は１．０％未満の
添加では改善効果が小さいため、下限を１．０％とし
た。また、強力なフェライト安定化元素であり、３％を
超える添加によりδ相を生成しやすくなる上、マルテン
サイト硬さも上昇することから、最適添加量を１．０〜
３％とした。Al: Al is added for the purpose of deoxidizing,
Sufficient effect can be obtained with addition of 0.06% or less.
If added over 06%, the toughness decreases, so the upper limit was made 0.06%. N: N is a strong austenite stabilizing element like Mn and Mo and is effective in preventing rolling flaws, but it increases the hardness of martensite like C. Therefore, the upper limit is set to 0.025%. Particularly, if it is 0.005% or less, the machinability is further improved. The lower the lower limit, the better. Mo: Mo is an essential element for improving pitting corrosion resistance and stress corrosion cracking resistance. These effects have little improvement effect when the addition is less than 1.0%, so the lower limit is set to 1.0%. Further, it is a strong ferrite stabilizing element, and if it exceeds 3%, the δ phase is easily generated, and the martensite hardness also rises.
3%.
【００１１】Ｃｕ：ＣｕはＮｉと同様に耐腐食性向上に
有効な元素であるとともに、オーステナイト安定化元素
でありδ相の生成を抑止し圧延疵防止に有効であるため
必要に応じて添加するが、０．５％未満ではこれらの効
果が十分に得られないため、下限を０．５％とした。ま
た、３．０％を超えて添加すると粒界に過剰に偏析して
粒界強度を低下させるため熱間加工性が著しく劣化する
ため、最適添加範囲を０．５〜３．０％とした。 Ｃａ：ＣａはＳによる熱間加工性劣化を抑制するもので
あり、必要に応じて添加するが、０．００１％未満では
その効果が発現されず、０．０２％を超えて添加しても
その効果は飽和するため、最適添加量を０．００１％〜
０．０２％とした。Cu: Cu, like Ni, is an element effective in improving the corrosion resistance, is an austenite stabilizing element, suppresses the formation of the δ phase, and is effective in preventing rolling flaws, so Cu is added if necessary. However, if less than 0.5%, these effects cannot be sufficiently obtained, so the lower limit was made 0.5%. Further, if added in excess of 3.0%, it is excessively segregated in the grain boundaries and the grain boundary strength is lowered, so that the hot workability is significantly deteriorated. Therefore, the optimum addition range is set to 0.5 to 3.0%. . Ca: Ca suppresses the deterioration of hot workability due to S, and is added as necessary, but if it is less than 0.001%, its effect is not exhibited, and if it exceeds 0.02%, it is added. Since the effect is saturated, the optimum addition amount is 0.001% ~
0.02%.
【００１２】Ｔｉ：重量％でＮの添加量の３．４倍以上
のＴｉを加えると凝固過程でＴｉＮが析出するので固溶
Ｎ量が減少し、焼入れマルテンサイト組織での硬さを低
減できるため、必要に応じて添加し、下限はＮの添加量
の３．４倍とした。また、必要以上に添加すると合金コ
ストが高くつくことから上限を効果の飽和する０．３％
とした。[0012] Ti: When Ti is added in an amount of 3.4 times the amount of N added in wt%, TiN is precipitated during the solidification process, so the amount of solute N is reduced, and the hardness in the quenched martensite structure can be reduced. Therefore, it is added as needed, and the lower limit is set to 3.4 times the amount of N added. In addition, if added more than necessary, the alloy cost will be high, so the upper limit is 0.3% to saturate the effect.
And
【００１３】次に、かかる組成の鋼のＣeqを制限する理
由について述べる。本発明者らは、合金添加量の異なる
種々の素材に対して焼入れマルテンサイト組織でのビッ
カーズ硬さを調査するとともに、通常の冷間鋸断工具で
切断試験を行った。その結果、図１に示すごとく、ビッ
カーズ硬さ３３０を境として、それ以下で冷間鋸断工具
のチッピングが著しく減少し、良好に切断可能であるこ
とを知見した。特に、ビッカーズ硬さで３００以下にす
れば被切削性がいっそう良くなり、冷間鋸断工具のチッ
ピングが起こらず、工具の長寿命化が可能であることを
知見した。さらに、各添加元素が焼入れマルテンサイト
組織でのビッカーズ硬さに及ぼす影響を解明した。すな
わち、マルテンサイト組織でのビッカーズ硬さはＣeq＝
Ｃ＋Ｎ＋０．０１７Ｎｉ＋０．０１５Ｍｏで整理できる
ことを見いだし、Ｃeqとマルテンサイト組織での硬さの
関係は図２のごとく求まった。これらより、Ｃeq≦０．
１５を満足すればマルテンサイト組織での硬さをビッカ
ーズ硬さで３３０以下にでき、軟化焼鈍なしに通常の工
具での冷間鋸断が可能となったのである。さらに、Ｃeq
≦０．１３を満足すれば焼入れマルテンサイト組織での
硬さをビッカーズ硬さで３００以下にでき、鋸断工具の
長寿命化も可能となったのである。Next, the reason for limiting the C eq of the steel having such a composition will be described. The present inventors investigated the Vickers hardness of a hardened martensite structure for various materials having different alloy addition amounts, and conducted a cutting test with a normal cold sawing tool. As a result, as shown in FIG. 1, it has been found that, with the Vickers hardness 330 as the boundary, below that, the chipping of the cold sawing tool is significantly reduced, and good cutting is possible. In particular, it has been found that when the Vickers hardness is 300 or less, the machinability is further improved, chipping of the cold sawing tool does not occur, and the tool life can be extended. Furthermore, the effect of each additive element on the Vickers hardness in the quenched martensite structure was clarified. That is, the Vickers hardness in the martensite structure is C eq =
It was found that it can be arranged by C + N + 0.017Ni + 0.015Mo, and the relationship between C eq and hardness in the martensite structure was obtained as shown in FIG. From these, C eq ≦ 0.
If the value of 15 is satisfied, the hardness in the martensite structure can be reduced to 330 or less in Vickers hardness, and cold sawing with a normal tool is possible without softening annealing. Furthermore, C eq
If ≦ 0.13 is satisfied, the hardness of the hardened martensite structure can be reduced to 300 or less in Vickers hardness, and the life of the sawing tool can be extended.
【００１４】一方、重量％でＮの添加量の３．４倍以上
のＴｉを加えた場合には、凝固過程でＴｉＮが析出する
ので固溶Ｎ量が減少するためＮの影響は無視でき、焼入
れマルテンサイト組織でのビッカーズ硬さは、Ｃeq’＝
Ｃ＋０．０１７Ｎｉ＋０．０１５Ｍｏで整理できること
を見いだした。重量％でＮの添加量の３．４倍以上のＴ
ｉを加えた場合において、Ｃeq’とマルテンサイト組織
での硬さの関係は、図３のごとく求まった。これらよ
り、重量％でＮの添加量の３．４倍以上のＴｉを加えた
場合には、Ｃeq’≦０．１５を満足すればマルテンサイ
ト組織での硬さをビッカーズ硬さ３３０以下にでき、軟
化焼鈍無しに通常の工具での冷間鋸断が可能となったの
である。さらに、Ｃeq’≦０．１３を満足すればマルテ
ンサイト組織での硬さをビッカーズ硬さ３００以下にで
き、鋸断工具の長寿命化が可能となったのである。On the other hand, when Ti is added in an amount of 3.4 times the amount of N added by weight%, TiN is precipitated in the solidification process, and the amount of solute N is reduced, so that the effect of N can be ignored. The Vickers hardness in the hardened martensite structure is C eq '=
It was found that it can be arranged with C + 0.017Ni + 0.015Mo. T of 3.4% by weight or more of N addition amount
When i was added, the relationship between C eq 'and the hardness in the martensite structure was obtained as shown in FIG. From these, when Ti is added in an amount of 3.4 times the amount of N added by weight%, the hardness in the martensite structure is reduced to Vickers hardness of 330 or less if C eq '≦ 0.15 is satisfied. It was possible, and cold sawing with normal tools was possible without softening and annealing. Furthermore, if C eq '≤0.13 is satisfied, the hardness in the martensitic structure can be reduced to Vickers hardness of 300 or less, and the life of the sawing tool can be extended.
【００１５】[0015]
【実施例】 ［実施例１］表１に示す組成の鋼を真空溶解にて溶製
し、５０kgインゴットに鋳造し、板厚１２mmまで熱間圧
延した幅６００mmの素材を用いて、圧延ままの硬さを調
べた。試験結果を表２に示す。これよりＣeqが低いほど
圧延ままの硬さが低くなり、Ｃeqが０．１５以下であれ
ば圧延ままの硬さがビッカーズ硬さで３３０以下にでき
ることがわかった。さらに、Ｃeqが０．１３以下であれ
ば圧延ままの硬さがビッカーズ硬さで３００以下にでき
ることがわかった。また、これらの素材を常温で１００
枚を幅方向に、直径８００mmの超硬丸鋸切断機で切断
し、工具（前記丸鋸刃）のチッピングの頻度を目視で調
べた。試験結果を表２に併せて示す。[Example 1] A steel having the composition shown in Table 1 was melted by vacuum melting, cast into a 50 kg ingot, and hot rolled to a plate thickness of 12 mm. I examined the hardness. The test results are shown in Table 2. From this, it was found that the lower the C eq , the lower the as-rolled hardness, and if the C eq is 0.15 or less, the as-rolled hardness can be 330 or less in Vickers hardness. Further, it was found that if C eq is 0.13 or less, the as-rolled hardness can be 300 or less in Vickers hardness. In addition, these materials are 100 at room temperature.
The sheets were cut in the width direction with a super hard circular saw cutting machine having a diameter of 800 mm, and the frequency of chipping of the tool (the circular saw blade) was visually examined. The test results are also shown in Table 2.
【００１６】Ｃeqが０．１５より大きい鋼（Ｈｖ＞３３
０）を切断した場合は工具のチッピングが頻繁に生じ、
実用上切断不可能であるが、Ｃeqが０．１５以下の鋼
（Ｈｖ≦３３０）を切断した場合は工具のチッピングの
頻度は実用上問題ない程度まで著しく減少した。これよ
り、Ｃeqを０．１５以下とすれば、必然的にＨｖ≦３３
０となり、軟化焼鈍することなしに直接冷間で、通常の
鋸断工具により切断することが可能であるといえる。ま
た、Ｃeqが０．１３以下の鋼（Ｈｖ≦３００）を切断し
た場合は工具のチッピングは起こらなかった。これよ
り、Ｃeqを０．１３以下とすれば、必然的にＨｖ≦３０
０となり、鋸断工具の長寿命化が可能であるといえる。Steel with C eq greater than 0.15 (Hv> 33
When 0) is cut, chipping of the tool frequently occurs,
Although it is practically impossible to cut, when steel having a C eq of 0.15 or less (Hv ≦ 330) is cut, the frequency of chipping of the tool is significantly reduced to a level where there is no practical problem. From this, if C eq is set to 0.15 or less, Hv ≦ 33 is inevitable.
It becomes 0, and it can be said that it is possible to cut directly with a normal sawing tool without softening and annealing. Further, when steel having a C eq of 0.13 or less (Hv ≦ 300) was cut, chipping of the tool did not occur. From this, if Ceq is set to 0.13 or less, Hv ≦ 30 is inevitable.
It becomes 0, and it can be said that the life of the sawing tool can be extended.
【００１７】[0017]
【表１】 [Table 1]
【００１８】[0018]
【表２】 [Table 2]
【００１９】［実施例２］重量％でＮの添加量の３．４
倍以上のＴｉを加えた場合の実施例について説明する。
表３に示す組成の鋼を真空溶解にて溶製し、５０kgイン
ゴットに鋳造し、板厚１２mmまで熱間圧延した幅６００
mmの素材を用いて、圧延ままの硬さを調べた。試験結果
を表４に示す。これよりＣeq’が低いほど圧延ままの硬
さが低くなり、Ｃeq’が０．１５以下であれば圧延まま
の硬さがビッカーズ硬さで３３０以下にできることがわ
かった。さらに、Ｃeq’が０．１３以下であれば圧延ま
まの硬さがビッカーズ硬さで３００以下にできることが
わかった。また、これらの素材を常温で１００枚を幅方
向に、直径８００mmの超硬丸鋸切断機で切断し、工具
（前記丸鋸刃）のチッピングの頻度を目視で調べた。試
験結果を表４に併せて示す。[Example 2] The addition amount of N at 3.4 wt% was 3.4.
An example in which Ti is added in an amount not less than double will be described.
A steel having the composition shown in Table 3 was melted by vacuum melting, cast into a 50 kg ingot, and hot-rolled to a plate thickness of 12 mm. Width 600
The as-rolled hardness was investigated using a material of mm. Table 4 shows the test results. From this, it was found that the lower the C eq ', the lower the as-rolled hardness, and if the C eq ' is 0.15 or less, the as-rolled hardness can be 330 or less in Vickers hardness. Further, it was found that if C eq 'is 0.13 or less, the as-rolled hardness can be 300 or less in Vickers hardness. Further, 100 sheets of these materials were cut at room temperature in the width direction with a carbide circular saw cutter having a diameter of 800 mm, and the frequency of chipping of the tool (the circular saw blade) was visually examined. The test results are also shown in Table 4.
【００２０】Ｃeq’が０．１５より大きい鋼（Ｈｖ＞３
３０）を切断した場合は工具のチッピングが頻繁に生
じ、実用上切断不可能であるが、Ｃeq’が０．１５以下
の鋼（Ｈｖ≦３３０）を切断した場合は工具のチッピン
グの頻度は実用上問題ない程度まで著しく減少した。こ
れより、Ｃeq’を０．１５以下とすれば、必然的にＨｖ
≦３３０となり、軟化焼鈍することなしに直接冷間で、
通常の鋸断工具により切断することが可能であるといえ
る。また、Ｃeq’が０．１３以下の鋼（Ｈｖ≦３００）
を切断した場合は工具のチッピングは起こらなかった。
これより、Ｃeq’を０．１３以下とすれば、必然的にＨ
ｖ≦３００となり、鋸断工具の長寿命化が可能であると
いえる。Steel with C eq 'greater than 0.15 (Hv> 3
When 30) is cut, chipping of the tool frequently occurs and it is practically impossible to cut, but when cutting steel (Hv ≦ 330) having C eq ′ of 0.15 or less, the frequency of tool chipping is Remarkably reduced to a level where there is no practical problem. From this, if C eq 'is 0.15 or less, Hv is inevitable.
≦ 330, and directly cold without softening annealing,
It can be said that it can be cut with a normal sawing tool. In addition, steel with C eq '0.13 or less (Hv ≤ 300)
No tool chipping occurred when cutting.
From this, if C eq 'is less than 0.13, then inevitably H
Since v ≦ 300, it can be said that the life of the sawing tool can be extended.
【００２１】[0021]
【表３】 [Table 3]
【００２２】[0022]
【表４】 [Table 4]
【００２３】[0023]
【発明の効果】以上のように、本発明によれば、鋳造ま
まあるいは分塊圧延後のスラブ、ブルーム、ビレットを
軟化焼鈍することなしに直接冷間で、通常の鋸断工具に
より切断することが可能となる。As described above, according to the present invention, a slab, a bloom or a billet as cast or after slabbing can be cut directly by a normal sawing tool without softening and annealing. Is possible.
【図１】ビッカーズ硬さと鋸断工具のチッピングの頻度
の関係を示す図。FIG. 1 is a diagram showing a relationship between Vickers hardness and frequency of chipping of a sawing tool.
【図２】Ｃeq（＝Ｃ＋Ｎ＋０．０１７Ｎｉ＋０．０１５
Ｍｏ）と焼入れマルテンサイト組織での硬さの関係を示
す図。FIG. 2 C eq (= C + N + 0.017Ni + 0.015)
The figure which shows the relationship between Mo) and the hardness in a quenched martensite structure.
【図３】Ｃeq’（＝Ｃ＋０．０１７Ｎｉ＋０．０１５Ｍ
ｏ）と焼入れマルテンサイト組織での硬さの関係を示す
図。FIG. 3 C eq '(= C + 0.017Ni + 0.015M
The figure which shows the relationship between o) and the hardness in a hardened martensite structure.
Claims (8)
１５ を満足し、残部がＦｅ及び不可避的不純物からなる低硬
度マルテンサイト系ステンレス鋼。1. By weight%, C: 0.025% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.01% or less, Cr : 11 to 17%, Ni: 4.5 to 7.0%, Al: 0.06% or less, N: 0.025% or less, Mo: 1.0 to 3.0%, and C eq = C + N + 0.017Ni + 0.015Mo ≦ 0.
A low-hardness martensitic stainless steel that satisfies 15 and the balance consists of Fe and inevitable impurities.
１５ を満足し、残部がＦｅ及び不可避的不純物からなる低硬
度マルテンサイト系ステンレス鋼。2. In% by weight, C: 0.025% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.01% or less, Cr : 11 to 17%, Ni: 4.5 to 7.0%, Al: 0.06% or less, N: 0.025% or less, Mo: 1.0 to 3.0%, and further Ca : 0.001 to 0.02%, Cu: 0.5 to 3.0% of one or two, and C eq = C + N + 0.017Ni + 0.015Mo ≦ 0.
A low-hardness martensitic stainless steel that satisfies 15 and the balance consists of Fe and inevitable impurities.
１３ を満足し、残部がＦｅ及び不可避的不純物からなる低硬
度マルテンサイト系ステンレス鋼。3. In% by weight, C: 0.005% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.01% or less, Cr : 11 to 17%, Ni: 4.5 to 7.0%, Al: 0.06% or less, N: 0.005% or less, Mo: 1.0 to 3.0%, and C eq = C + N + 0.017Ni + 0.015Mo ≦ 0.
A low-hardness martensitic stainless steel that satisfies 13 and the balance consists of Fe and inevitable impurities.
１３ を満足し、残部がＦｅ及び不可避的不純物からなる低硬
度マルテンサイト系ステンレス鋼。4. In% by weight, C: 0.005% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.01% or less, Cr 11 to 17%, Ni: 4.5 to 7.0%, Al: 0.06% or less, N: 0.005% or less, Mo: 1.0 to 3.0%, and further Ca : 0.001 to 0.02%, Cu: 0.5 to 3.0% of one or two, and C eq = C + N + 0.017Ni + 0.015Mo ≦ 0.
A low-hardness martensitic stainless steel that satisfies 13 and the balance consists of Fe and inevitable impurities.
５ を満足し、残部がＦｅ及び不可避的不純物からなる低硬
度マルテンサイト系ステンレス鋼。5. By weight%, C: 0.025% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.01% or less, Cr : 11 to 17%, Ni: 4.5 to 7.0%, Al: 0.06% or less, N: 0.025% or less, Mo: 1.0 to 3.0%, Ti: 3.4N or more. 0.3% and C eq '= C + 0.017Ni + 0.015Mo≤0.1
A low-hardness martensitic stainless steel which satisfies 5 and the balance is Fe and inevitable impurities.
５ を満足し、残部がＦｅ及び不可避的不純物からなる低硬
度マルテンサイト系ステンレス鋼。6. By weight%, C: 0.025% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.01% or less, Cr : 11 to 17%, Ni: 4.5 to 7.0%, Al: 0.06% or less, N: 0.025% or less, Mo: 1.0 to 3.0%, Ti: 3.4N or more. 0.3%, Ca: 0.001 to 0.02%, Cu: 0.5 to 3.0%, one or two kinds, and C eq ′ = C + 0.017Ni + 0. .015Mo ≦ 0.1
A low-hardness martensitic stainless steel which satisfies 5 and the balance is Fe and inevitable impurities.
３ を満足し、残部がＦｅ及び不可避的不純物からなる低硬
度マルテンサイト系ステンレス鋼。7. By weight%, C: 0.005% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.01% or less, Cr : 11 to 17%, Ni: 4.5 to 7.0%, Al: 0.06% or less, N: 0.025% or less, Mo: 1.0 to 3.0%, Ti: 3.4N or more. 0.3% and C eq '= C + 0.017Ni + 0.015Mo≤0.1
3. A low hardness martensitic stainless steel that satisfies 3 and the balance is Fe and inevitable impurities.
３ を満足し、残部がＦｅ及び不可避的不純物からなる低硬
度マルテンサイト系ステンレス鋼。8. In% by weight, C: 0.005% or less, Si: 0.5% or less, Mn: 1.5% or less, P: 0.03% or less, S: 0.01% or less, Cr : 11 to 17%, Ni: 4.5 to 7.0%, Al: 0.06% or less, N: 0.025% or less, Mo: 1.0 to 3.0%, Ti: 3.4N or more. 0.3%, Ca: 0.001 to 0.02%, Cu: 0.5 to 3.0%, one or two kinds, and C eq ′ = C + 0.017Ni + 0. .015Mo ≦ 0.1
3. A low hardness martensitic stainless steel that satisfies 3 and the balance is Fe and inevitable impurities.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12712996A JPH09291344A (en) | 1996-02-26 | 1996-05-22 | Low hardness martensitic stainless steel |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3854796 | 1996-02-26 | ||
| JP8-38547 | 1996-02-26 | ||
| JP12712996A JPH09291344A (en) | 1996-02-26 | 1996-05-22 | Low hardness martensitic stainless steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09291344A true JPH09291344A (en) | 1997-11-11 |
Family
ID=26377809
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12712996A Pending JPH09291344A (en) | 1996-02-26 | 1996-05-22 | Low hardness martensitic stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09291344A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1143024A1 (en) * | 1998-12-18 | 2001-10-10 | Nkk Corporation | Martensitic stainless steel |
| JP2003226932A (en) * | 2002-02-01 | 2003-08-15 | Nkk Bars & Shapes Co Ltd | Free-cutting steel |
| EP1717328A1 (en) * | 2004-01-30 | 2006-11-02 | JFE Steel Corporation | Martensitic stainless steel tube |
| WO2010050519A1 (en) | 2008-10-30 | 2010-05-06 | 住友金属工業株式会社 | High strength stainless steel piping having outstanding resistance to sulphide stress cracking and resistance to high temperature carbon dioxide corrosion |
| WO2018181404A1 (en) * | 2017-03-28 | 2018-10-04 | 新日鐵住金株式会社 | Martensitic stainless steel material |
-
1996
- 1996-05-22 JP JP12712996A patent/JPH09291344A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1143024A1 (en) * | 1998-12-18 | 2001-10-10 | Nkk Corporation | Martensitic stainless steel |
| EP1143024A4 (en) * | 1998-12-18 | 2002-08-07 | Nippon Kokan Kk | Martensitic stainless steel |
| JP2003226932A (en) * | 2002-02-01 | 2003-08-15 | Nkk Bars & Shapes Co Ltd | Free-cutting steel |
| EP1717328A1 (en) * | 2004-01-30 | 2006-11-02 | JFE Steel Corporation | Martensitic stainless steel tube |
| EP1717328A4 (en) * | 2004-01-30 | 2012-03-28 | Jfe Steel Corp | Martensitic stainless steel tube |
| WO2010050519A1 (en) | 2008-10-30 | 2010-05-06 | 住友金属工業株式会社 | High strength stainless steel piping having outstanding resistance to sulphide stress cracking and resistance to high temperature carbon dioxide corrosion |
| US8608872B2 (en) | 2008-10-30 | 2013-12-17 | Nippon Steel & Sumitomo Metal Corporation | High-strength stainless steel pipe excellent in sulfide stress cracking resistance and high-temperature carbonic-acid gas corrosion resistance |
| WO2018181404A1 (en) * | 2017-03-28 | 2018-10-04 | 新日鐵住金株式会社 | Martensitic stainless steel material |
| RU2718019C1 (en) * | 2017-03-28 | 2020-03-30 | Ниппон Стил Корпорейшн | Martensitic stainless steel product |
| EP3604591A4 (en) * | 2017-03-28 | 2020-09-02 | Nippon Steel Corporation | Martensitic stainless steel material |
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