JP2011047008A5

JP2011047008A5 -

Info

Publication number: JP2011047008A5
Application number: JP2009197116A
Authority: JP
Filing date: 2009-08-27
Publication date: 2011-09-01

Description

発明者らは、前記課題を解決するために鋭意研究を重ねた結果、以下に示す発明を完成するに至った。すなわち、請求項１に記載した発明は、
（１）質量％で、Ｃ≦０．１５％、Ｓｉ≦４．０％、４．０％≦Ｍｎ≦１０．０％、Ｐ≦０．１０％、Ｓ≦０．０１０％、２．０％≦Ｎｉ≦６．０％、１６．０％≦Ｃｒ≦１８．０％、０．０５％≦Ｎ≦０．２０％を含有し、残部がＦｅおよび不可避不純物からなり、
（２）Ｍｄ₃₀Ｍｎ＝５５１−４６２(％Ｃ＋％Ｎ)−２９(％Ｎｉ＋％Ｃｕ)＋４．８％Ｓｉ−１９．１％Ｍｎ−１３．７％Ｃｒ−１８．５％Ｍｏに従うＭｄ₃₀Ｍｎ値が、−３５≦Ｍｄ₃₀Ｍｎ≦０を満たし、
（３）冷間圧延によって１３２０ＭＰａ以上の引張強さが付与されたことを特徴とする、
（４）ばね用オーステナイト系ステンレス鋼
である。 The inventors have intensively studied to solve the above problems, and as a result, have completed the invention shown below. That is, the invention described in claim 1
(1) By mass%, C ≦ 0.15%, Si ≦ 4.0%, 4.0% ≦ Mn ≦ 10.0%, P ≦ 0.10%, S ≦ 0.010%, 2.0 % ≦ Ni ≦ 6.0%, 16.0% ≦ Cr ≦ 18.0%, 0.05% ≦ N ≦ 0.20%, with the balance being Fe and inevitable impurities,
_{(2) Md 30 Mn = 551-} 462 (% C +% N) Md 30 according to -29 (% Ni +% Cu) + 4.8% Si-19.1% Mn-13.7% Cr-18.5% Mo Mn value satisfies −35 ≦ Md ₃₀ Mn ≦ 0,
(3) A tensile strength of 1320 MPa or more is imparted by cold rolling,
(4) Austenitic stainless steel for spring.

９）−３５≦Ｍｄ₃₀Ｍｎ≦０：Ｍｄ₃₀Ｍｎ値は、オーステナイト系ステンレス鋼を加工した際に生じる加工誘起マルテンサイト(α´)変態のし易さを表す指標で、Ｍｄ₃₀Ｍｎ＝５５１−４６２(％Ｃ＋％Ｎ)−２９(％Ｎｉ＋％Ｃｕ)＋４．８％Ｓｉ−１９．１％Ｍｎ−１３．７％Ｃｒ−１８．５％Ｍｏに従って求められる。この値が大きいほど、同マルテンサイト変態が生じ易い。Ｍｄ₃₀Ｍｎ値が大きいと、圧延に多量の加工誘起マルテンサイト(α´)相が生じ、調質圧延板の加工性は低下し、さらに、圧延後のコイル形態における時期割れ懸念が高まるため、Ｍｄ₃₀Ｍｎ≦０が望ましい。一方、Ｍｄ₃₀Ｍｎ値が小さいと、調質圧延板の成形時に生じる加工誘起マルテンサイト(α´)相が減少し、十分な延性・成形性が得られないため、−３５≦Ｍｄ₃₀Ｍｎが望ましい。なお、上式における「％」は「質量％」を意味し、「％元素記号」は「鋼中における元素の配合割合を質量％で表したもの」を意味する。 9) −35 ≦ Md ₃₀ Mn ≦ 0: The Md ₃₀ Mn value is an index representing the ease of processing-induced martensite (α ′) transformation that occurs when processing austenitic stainless steel, and Md ₃₀ Mn = 551. -462 (% C +% N)-29 (% Ni +% Cu) + 4.8% Si-19.1% Mn-13.7% Cr-18.5% Mo. The larger this value, the easier the martensitic transformation occurs. If the Md ₃₀ Mn value is large, a large amount of work-induced martensite (α ′) phase occurs in rolling, the workability of the temper rolled sheet is lowered, and further, there is an increased concern about time cracking in the coil form after rolling. Md ₃₀ Mn ≦ 0 is desirable. On the other hand, if the Md ₃₀ Mn value is small, the work-induced martensite (α ′) phase generated during the shaping of the temper rolled sheet is reduced, and sufficient ductility and formability cannot be obtained. Therefore, −35 ≦ Md ₃₀ Mn is desirable. In the above formula, “%” means “% by mass”, and “% element symbol” means “a ratio of elements in steel expressed in mass%”.

Claims

% By mass, C ≦ 0.15%, Si ≦ 4.0%, 4.0% ≦ Mn ≦ 10.0%, P ≦ 0.10%, S ≦ 0.010%, 2.0% ≦ Ni ≦ 6.0%, 16.0% ≦ Cr ≦ 18.0%, 0.05% ≦ N ≦ 0.20%, with the balance being Fe and inevitable impurities,
_{Md 30 Mn = 551- 462 (%} C +% N) -29 (% Ni +% Cu) + Md 30 Mn value according to 4.8% Si-19.1% Mn- 13.7% Cr-18.5% Mo is , −35 ≦ Md ₃₀ Mn ≦ 0 is satisfied,
An austenitic stainless steel for springs, which is provided with a tensile strength of 1320 MPa or more by cold rolling.