KR100415918B1 - METHOD FOR HEAT TREATING 13% Cr MARTENSITIC STAINLESS STEEL - Google Patents

METHOD FOR HEAT TREATING 13% Cr MARTENSITIC STAINLESS STEEL Download PDF

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KR100415918B1
KR100415918B1 KR1019960056457A KR19960056457A KR100415918B1 KR 100415918 B1 KR100415918 B1 KR 100415918B1 KR 1019960056457 A KR1019960056457 A KR 1019960056457A KR 19960056457 A KR19960056457 A KR 19960056457A KR 100415918 B1 KR100415918 B1 KR 100415918B1
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stainless steel
martensitic stainless
heat treating
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steel
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KR1019960056457A
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KR19980037664A (en
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김기돈
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주식회사 포스코
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/008—Martensite

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

PURPOSE: A method for heat treating 13% Cr martensitic stainless steel is provided to secure high strength and excellent impact toughness at the same time without generation of lamination on hot rolled strip or cold rolled strip. CONSTITUTION: The method for heat treating 13% Cr martensitic stainless steel comprises a step of performing aging treatment on martensitic stainless steel containing 13 wt.% of Cr, 0.12 to 0.18 wt.% of N and 0.03 to 0.08 wt.% of Nb in the temperature range of 600 to 650 deg.C for 200 to 330 hours; a step of water cooling the aged martensitic stainless steel; a step of tempering the water cooled martensitic stainless steel in the temperature range of 700 to 720 deg.C for 28 to 35 hours; and a step of water cooling the tempered martensitic stainless steel so that high strength and superior impact toughness are secured at the same time.

Description

13%Cr 마르텐사이트계 스테인리스강이 열처리 방법.Heat treatment method of 13% Cr martensitic stainless steel.

본 발명은 13% Cr을 함유하는 마르텐사이트계 스테인리스강의 열처리 방법에 관한 것으로서, 더욱 상세하게는 높은 강도와 우수한 충격 인성을 동시에 확보하는 13% Cr 마르텐사이트계 스테인리스강의 열처리 방법에 관한 것이다.The present invention relates to a heat treatment method for a martensitic stainless steel containing 13% Cr, and more particularly to a heat treatment method for 13% Cr martensitic stainless steel which secures both high strength and excellent impact toughness.

기존의 13% Cr 마르텐사이트계 스테인리스강 제품의 열처리방법은 기존의 공정 순서도인 도1에서 도시된 바와 같이, 0.2-0.3% C이 함유된 소재를 용해-압연-상소둔-냉간압연-연간소둔 한 다음, 최종적으로 제품가공하여 소입-소려 열처리하는 과정을 거치는데, 이 방법으로는 경도를 최대화할 수 없을 뿐만 아니라 충격인성 확보에도 문제가 있으며, 특히 C만으로 경도를 확보할 수 밖에 없기 때문에 열연스트립이나 냉연스트립이나 냉연스트립에 이중판(lamination)이 발생하는 경우가 있었다.The conventional heat treatment method for 13% Cr martensitic stainless steel product is a method of melting and rolling a material containing 0.2-0.3% C, as shown in FIG. 1, which is a conventional process flow chart, After that, the final product is processed and subjected to a heat treatment of quenching and plowing. In this method, not only hardness can be maximized but also impact toughness can not be secured. In particular, since hardness can be secured only by C, Lamination occurred in strips or cold-rolled strips or cold-rolled strips.

그리고, 본 발명과 관련된 문헌이나 특허의 예로는 다음과 같은 것들이 있다. Shimada, T.의 A Method to Obtain Fine Chromium Carbides in High Carbon Martensitic Stainless Steel [Process and Materials : Innovation Stainless steel Vol.2] ; I.Devalliere의 Martensitic Stainless Steels in Cutlery [Trzit. Therm., (230),p.61-64] ; Hamman G.의 Corrosion Resistance of Surgical Instruments [Met. Prog.,127, (6),p.61-62,64-65] ; P.J.Hidalgo의 Corrosion Phenomena in AISI 420 Martensitic Stainless Steel [Deform Met., (69),p.60-70] ; M.B Horovitz의 Nitrogen Bearing Martensitic Stainless Steels [ISIJ International, Vol.36 (1996) No. 7,p.840-845] ; N.Nakamura의 Structural Control of Stainless Steel by Nitrogen Absorption in Solid State [ISIJ International, Vol.36 (1996) No.7 p.922-926] ; Descaling Chromium Stainless Steel 의 명칭을 갖는 일본특허 58081927호; 및 Annealing Stainless Steel Strip without Removing Oxide Scale 의 명칭을 갖는 미국특허 제3776784호.Examples of documents and patents related to the present invention include the following. Shimada, T. A Method to Obtain Fine Chromium Carbides in High Carbon Martensitic Stainless Steel [Process and Materials: Innovation Stainless steel Vol.2]; I.Devalliere's Martensitic Stainless Steels in Cutlery [Trzit. Therm., (230), p. 61-64]; Hamman G. Corrosion Resistance of Surgical Instruments [Met. Prog., 127, (6), p. 61-62, 64-65; P.J. Hidalgo, Corrosion Phenomena in AISI 420 Martensitic Stainless Steel [Deform Met. (69), p.60-70]; M.B Horovitz's Nitrogen Bearing Martensitic Stainless Steels [ISIJ International, Vol. 7, pp. 840-845; Structural Control of Stainless Steel by N. Nakamura by Nitrogen Absorption in Solid State [ISIJ International, Vol. 36 (1996) No. 7 p. 922-926]; Japanese Patent No. 58081927, which is named Descaling Chromium Stainless Steel; And US 3776784, entitled " Annealing Stainless Steel Strip without Removing Oxide Scale ".

그러나, 상기의 언급된 문헌이나 특허들중 그 어느것도 13%Cr 마르텐사이트계 스테인리스강의 강도와 충격인성을 향상시키는 열처리 방법에 관하여 직접적으로 언급하고 있지 않다.However, none of the above-mentioned references or patents mention directly the heat treatment method for improving the strength and impact toughness of 13% Cr martensitic stainless steels.

따라서, 본 발명의 목적은 열연스트립이나 냉연 스트립에 이중판을 발생시킴이 없이 높은 강도와 우수한 충격 인성을 동시에 확보하는 13%Cr 마르텐사이트계 스테인리스강의 열처리 방법을 제공하는데 있다.Accordingly, an object of the present invention is to provide a heat treatment method of 13% Cr martensitic stainless steel which secures both high strength and excellent impact toughness without generating a double plate on a hot-rolled strip or a cold-rolled strip.

도1은 기존의 13% 마르텐사이트계 스테인리스강 제품의 열처리 방법을 보여주는 공정 순서도,FIG. 1 is a process flow chart showing a conventional heat treatment method for a 13% martensitic stainless steel product,

도2는 본 발명에 따른 13%마르텐사이트계 스테인리스강의 열처리 방법을 보여주는 공정순서도,2 is a process flow diagram showing a heat treatment method of 13% martensitic stainless steel according to the present invention,

도3 (가) 내지 (나)는 본 발명의 실시예 1에 따라 시효처리했을 때의 시효시간에 따른 경도 변화를 보여주는 그래프,3 (A) to 3 (B) are graphs showing changes in hardness with aging time when aging treatment according to Example 1 of the present invention,

도4 (가) 내지 (다)는 본 발명의 실시예3에 따라 소려 조건 변화 실험을 실시하였을 때의 결과를 보여주는 그래프이다.FIGS. 4A to 4C are graphs showing results of a bell condition change test according to the third embodiment of the present invention. FIG.

상기의 목적을 달성하기 위하여, 본 발명은 13%Cr을 함유하는 마르텐사이트계 스테인리스강에 중량%로 N 성분을 0.12~0.18%, Nb 성분을 0.03~0.08% 함유시킨 강을 600-650℃ 범위에서 200~330 시간 시효처리한 다음, 수냉한 소재를 다시 700~720℃ 범위에서 28~35 시간 소려한 다음 수냉하여, 높은 강도와 우수한 충격 인성을 동시에 확보하는 13% Cr 마르텐사이트계 스테인리스강 열처리방법을 제공한다.In order to achieve the above object, the present invention provides a method for producing a steel comprising the steps of: mixing a steel containing 0.12 to 0.18% of N component and 0.03 to 0.08% of Nb component in a martensitic stainless steel containing 13% And then subjected to aging for 200 to 330 hours and then cooled in a temperature range of 700 to 720 ° C for 28 to 35 hours, and then water-cooled to obtain a 13% Cr martensitic stainless steel heat treatment ≪ / RTI >

이하, 본 발명을 더욱 상세히 설명하기로 한다.Hereinafter, the present invention will be described in more detail.

본 발명은 발명에 따른 열처리 방법을 보여주는 공정 순서도인 도2에서 표시된 바와 같이, 고용화 소둔과 시효처리에 의해 강도를 극대화한 다음 소려하여 강도와 인성을 동시에 추구하는 열처리 방법을 사용하고 있다.As shown in FIG. 2, which is a process flow chart showing a heat treatment method according to the present invention, a heat treatment method which maximizes strength by solid solution annealing and aging treatment and searched simultaneously for strength and toughness is used.

그리고, 본 발명의 하기실시예 1내지 3에 따른 열처리 방법에서 사용되는 발명강 및 비교강종의 조성은 다음 (표1)과 같다:The composition of the invention steels and comparative steels used in the heat treatment methods according to Examples 1 to 3 of the present invention is as shown in Table 1 below:

(표1) 발명강 및 비교강의 조성(Table 1) Composition of invention steel and comparative steel

상기(표1)에서의 강번 1 및 2에서, C를 0.3% 함유하는 기존의 420J2 강종의 C를 0.12~0.18% 범위에서 N으로 대체시키고, 나이트라이드(Nitride)를 미세하게 석출시키고 성장을 억제하기 위해 Nb를 0.5% 함유시켰다. 여기서, 경도를 향상시키기 위해 첨가되는 N의 함량범위를 0.12~0.18%로 한 것은 0.12%이하이면 강도가 부족해지고, 0.18% 이상은 고용되지 않기 때문이다.In Steel Nos. 1 and 2 in Table 1, C of a conventional 420J2 steel containing 0.3% of C was substituted with N in the range of 0.12 to 0.18%, fine precipitation of nitrides and suppression of growth Nb was added in an amount of 0.5%. Here, when the content of N added to improve hardness is in the range of 0.12 to 0.18%, the strength is insufficient and 0.18% or more is not solved if the content is 0.12% or less.

(실시예 1)(Example 1)

상기 표 1에서의 4강종을 각각 1200℃에서 1.5시간 동안 고용화소둔시킨 후 공냉하다가 일정온도구역 (550~700℃)에서 시효처리했을 때의 시효시간에 따른 경도변화를 도3 (가) 내지 (라)에 나타내었다. 도3(가)에서 (가)내지 (라)에서, (가)는 1번강종, (나)는 2번강종, (다)는 3번강종, (라)는 4번 강종에 대한 것이다. 도3 (가) 내지 (라)를 참조하면, 강종 3,4는 Nb가 함유되어 있지 않기 때문에 Cr-N의 초기석출물이 성장하여 강도가 더 이상 높아지지 않는 것을 알 수 있는데 이는 금속 현미경상으로도 확인할 수 있었다. 또한 시효온도는 625℃가 가장 적절하며, 550℃에서는 시효가 충분히 일어나지 않으며, 700℃에서는 과시효 때문에 오히려 경도가 하락하므로 적정시효처리 조건은 600~650℃ 범위에서 200~330 시간 유지하는 것이 좋다는 것을 알 수 있다.The hardness changes according to the aging time when the quadruple species shown in Table 1 were aged at a constant temperature zone (550 to 700 ° C) after each of the quadruple species was left to stand for 1.5 hours at 1200 ° C., As shown in Fig. In Fig. 3 (a) to (d), (a) is for grade 1, (b) for grade 2, (c) for grade 3, and (d) for grade 4. Referring to Figs. 3 (A) to 3 (D), it can be seen that since Nb is not contained in the steel types 3 and 4, the initial precipitates of Cr-N grow and the strength is not further increased. . In addition, the aging temperature is most suitable at 625 ° C, the aging does not occur sufficiently at 550 ° C, and the hardness is lowered at 700 ° C due to the aging effect, so proper aging treatment conditions are preferably maintained at 600 to 650 ° C for 200 to 330 hours .

(실시예2)(Example 2)

상기 (표1)에서의 초기 대상강종 4종류중에서 3,4번 강종을 제외하고 강도향상효과가 더 큰 1번 강종을 대상으로 하여 Nb 함량만을 변화시켜 실시예 1에서와 같은 실험을 실시한 결과 다음 (표2)와 같은 결과를 얻었다.As a result of conducting the same experiment as in Example 1, only the Nb content was changed for the No. 1 steel having the greater strength improvement effect except the No. 3 steel grade among the initial target steel types in Table 1 above (Table 1) (Table 2).

(표2) Nb함량 변화에 따른 시효후의 경도(Table 2) Hardness after aging with changes in Nb content

상기의 (표2)로 부터, Nb을 0.03~0.10% 함유시켰을 때 Cr-N 미세화석출 및 성장억제효과가 있음을 알 수 있으며, 0.10% 이상을 함유시켜도 더 이상의 경도향상효과가 없고 Nb 원소의 값이 비싼 점을 고려하면 Nb 함유 적정범위는 0.03~0.08%인 것으로 판단된다.From the above Table 2, it can be seen that when Nb is contained in the range of 0.03 to 0.10%, the effect of suppressing the precipitation of Cr-N is suppressed and the growth is inhibited. Even if the Nb content is 0.10% or more, It is judged that the optimum range of Nb content is 0.03 to 0.08%.

(실시예 3)(Example 3)

고용화소둔과 시효처리가 끝난 시편을 수냉하고 소려처리하여, 강도와 충격 인성을 극대화하기 위해 (표1)에서의 강종 1을 대상으로 하여 소려조건 변화실험을 실시하였다. 그 결과를 도4 (가)내지 (다)에 나타내었는데 도4 (나)에서 표시된 바와 같이 소려온도 710℃에서 26~30시간 유지했을 때 경도와 충격인성이 효과적으로 균형을 이루는 것을 알 수 있다.In order to maximize strength and impact toughness by water cooling and tempering, the specimens subjected to agglomeration and aging treatment were subjected to a change of bending condition for the steel type 1 in Table 1. The results are shown in Figs. 4 (A) to 4 (C). As shown in Fig. 4 (B), it can be seen that the hardness and the impact toughness are effectively balanced when the bake temperature is maintained at 710 캜 for 26 to 30 hours .

이상에서 설명한 바와 같이, 본 발명방법에 따라 열처리된 강종은 강도의 향상을 위해 N성분을 첨가했기 때문에 이중판이 발생하지 않을 뿐만 아니라 강도가 높고 충격인성이 우수하다. 또한, C 단독첨가강보다 강도가 훨씬 높고 내공식성도 부가적으로 향상되기 때문에 이 강종을 도물류 생산에 이용할 경우, 부가가치가 높아지고 수명도 연장되는 잇점이 있다.As described above, the steel sheet heat-treated according to the method of the present invention has high strength and impact toughness as well as no double plate because the N component is added to improve the strength. In addition, since the strength is much higher than that of C-added steel and additionally improves the formability, this steel grade also has an advantage in that the added value is increased and the service life is prolonged.

Claims (1)

13%Cr을 함유하는 마르텐사이트계 스테인리스강에 중량%로 N 성분을 0.12~0.18 %, Nb 성분을 0.03~0.08% 함유시킨 강을 600-650℃ 범위에서 200~330 시간 시효처리한 다음, 수냉한 소재를 다시 700~720℃ 범위에서 28~35시간 소려한 다음 수냉하여, 높은 강도와 우수한 충격인성을 동시에 확보하는 13% Cr 마르텐사이트계 스테인리스강 열처리방법.A steel containing 0.12 to 0.18% by weight of N component and 0.03 to 0.08% by weight of Nb component in martensitic stainless steel containing 13% Cr is aged at 600 to 650 ° C for 200 to 330 hours, A 13% Cr martensitic stainless steel heat treatment method in which one material is cooled again in the range of 700 ~ 720 ℃ for 28 ~ 35 hours and then water cooled to ensure high strength and excellent impact toughness.
KR1019960056457A 1996-11-22 1996-11-22 METHOD FOR HEAT TREATING 13% Cr MARTENSITIC STAINLESS STEEL KR100415918B1 (en)

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KR100755181B1 (en) * 2006-07-31 2007-09-03 주식회사 포스코 Quenching method of martensitic stainless steel

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JPS60177134A (en) * 1984-02-24 1985-09-11 Nisshin Steel Co Ltd Production of stainless steel blade
JPS62103319A (en) * 1982-02-19 1987-05-13 Kawasaki Steel Corp Production of stainless steel products having high strength and excellent resistance to corrosion, stress corrosion cracking and sulfide cracking
JPH02217444A (en) * 1989-02-18 1990-08-30 Nippon Steel Corp High strength martensitic stainless steel having excellent corrosion resistance and stress corrosion cracking resistance and its manufacture

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Publication number Priority date Publication date Assignee Title
JPS62103319A (en) * 1982-02-19 1987-05-13 Kawasaki Steel Corp Production of stainless steel products having high strength and excellent resistance to corrosion, stress corrosion cracking and sulfide cracking
JPS60177134A (en) * 1984-02-24 1985-09-11 Nisshin Steel Co Ltd Production of stainless steel blade
JPH02217444A (en) * 1989-02-18 1990-08-30 Nippon Steel Corp High strength martensitic stainless steel having excellent corrosion resistance and stress corrosion cracking resistance and its manufacture

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