KR20150137629A - Part for generating unit and method of manufacturing the same - Google Patents

Part for generating unit and method of manufacturing the same Download PDF

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KR20150137629A
KR20150137629A KR1020140065789A KR20140065789A KR20150137629A KR 20150137629 A KR20150137629 A KR 20150137629A KR 1020140065789 A KR1020140065789 A KR 1020140065789A KR 20140065789 A KR20140065789 A KR 20140065789A KR 20150137629 A KR20150137629 A KR 20150137629A
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cooling
power generation
present
component
tempering
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KR101581557B1 (en
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최화열
염성호
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현대제철 주식회사
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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
    • C21D11/00—Process control or regulation for heat treatments
    • C21D11/005—Process control or regulation for heat treatments for cooling
    • 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
    • C21D1/26—Methods of annealing
    • C21D1/28—Normalising
    • 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
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten

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  • 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 Articles (AREA)

Abstract

Disclosed are a part for a power generating facility and a manufacturing method thereof. The part for a power generating facility according to the present invention comprises the steps of: inputting, into a mold, and solidifying molten metal composed of 0.16-0.18 wt% of carbon (C), 0.3-0.4 wt% of silicon (Si), 0.6-0.8 wt% of manganese (Mn), 0.001-0.015 wt% of phosphorus (P), 0.001-0.008 wt% of sulfur (S), 0.001-0.035 wt% of aluminum (Al), 0.55-0.75 wt% of nickel (Ni), 1.35-1.45 wt% of chromium (Cr), 0.95-1.05 wt% of molybdenum (Mo), 0.2-0.3 wt% of vanadium (V), the remainder consisting of iron (Fe), and inevitable impurities; normalizing the solidified output at temperatures equal to or higher than Ac3; cooling the normalized output; and tempering the normalized output, wherein the cooling is conducted at an average cooling speed of 0.25-0.40°C/sec.

Description

발전설비용 부품 및 그 제조 방법 {PART FOR GENERATING UNIT AND METHOD OF MANUFACTURING THE SAME}BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a component for a power generation facility,

본 발명은 발전설비용 부품 제조 기술에 관한 것으로, 보다 상세하게는 주조(casting)를 통하여 제조된 발전설비용 부품 및 그 제조 방법에 관한 것이다.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a component manufacturing technology for power generation equipment, and more particularly, to a component for power generation equipment manufactured through casting and a manufacturing method thereof.

증기 터빈 하우징과 같은 발전설비용 부품은 고온 고압에서 사용된다. 이러한 발전설비용 부품은 기계적 물성 및 조직 제어에 의한 크랙 발생을 방지하여야 한다. Parts for power generation equipment such as steam turbine housings are used at high temperature and high pressure. These parts for power generation facilities should prevent the occurrence of cracks due to mechanical properties and tissue control.

조직 제어를 위하여 공냉 방법으로 냉각을 수행할 경우, 과냉조직이 충분히 생성되지 않아 기계적 물성 확보가 어렵다. 반면, 조직 제어를 위해 수냉 방법으로 냉각을 수행할 경우, 열응력에 의한 크랙이 발생할 가능성이 있다.
When cooling is carried out by the air cooling method for controlling the structure, it is difficult to secure mechanical properties because the supercooled structure is not sufficiently generated. On the other hand, when cooling is performed by a water cooling method for controlling the structure, there is a possibility of cracking due to thermal stress.

본 발명에 관련된 배경기술로는 대한민국 공개특허공보 제10-2013-0012957호(2013.02.05. 공개)에 개시되어 있는 상온 인성이 우수한 페라이트계 내열 주강 및 그것으로 이루어진 배기계 부품이 있다.
Background art related to the present invention is a ferrite heat-resisting cast steel excellent in room temperature toughness disclosed in Korean Patent Laid-Open Publication No. 10-2013-0012957 (published on Mar. 23, 2013) and an exhaust system component made of the same.

본 발명의 목적은 합금성분 및 공정조절을 통하여 과냉 조직을 가져 우수한 기계적 특성을 발휘할 수 있으면서, 크랙 발생을 방지할 수 있는 발전설비용 부품 및 그 제조 방법을 제공하는 것이다.
An object of the present invention is to provide a component for a power generation facility and a method of manufacturing the same, which can prevent cracking while exhibiting supercooled structure through control of an alloy component and a process and exhibiting excellent mechanical characteristics.

상기 목적을 달성하기 위한 본 발명의 실시예에 따른 발전설비용 부품 제조 방법은 중량%로, 탄소(C) : 0.16~0.18%, 실리콘(Si): 0.3~0.4%, 망간(Mn) : 0.6~0.8%, 인(P) : 0.001~0.015%, 황(S) : 0.001~0.008%, 알루미늄(Al) : 0.001~0.035%, 니켈(Ni) : 0.55~0.75%, 크롬(Cr) : 1.35~1.45%, 몰리브덴(Mo) : 0.95~1.05%, 바나듐(V) : 0.2~0.3% 및 나머지 철(Fe)과 불가피한 불순물로 이루어진 용탕을 주형 내에 투입하여 응고하는 단계; 상기 응고된 결과물을 Ac3 이상의 온도에서 노말라이징 처리하는 단계; 상기 노말라이징 처리된 결과물을 냉각하는 단계; 및 상기 노말라이징된 결과물을 템퍼링하는 단계;를 포함하고, 상기 냉각은 0.25~0.40℃/sec의 평균냉각속도로 수행되는 것을 특징으로 한다. In order to achieve the above object, the present invention provides a method of manufacturing a component for power generation facilities, comprising: 0.16 to 0.18% of carbon (C), 0.3 to 0.4% of silicon (Si) (Al): 0.001 to 0.035%, nickel (Ni): 0.55 to 0.75%, chromium (Cr): 1.35%, phosphorus (P): 0.001 to 0.015% Of molybdenum (Mo): 0.95 to 1.05%, vanadium (V): 0.2 to 0.3%, and remaining iron (Fe) and unavoidable impurities in a mold; Subjecting the solidified product to a normalizing treatment at a temperature of Ac3 or higher; Cooling the resulting normalized product; And tempering the normalized product, wherein the cooling is performed at an average cooling rate of 0.25 to 0.40 ° C / sec.

이때, 상기 냉각은 워터 스프레이(water spray) 방식으로 수행되는 것이 바람직하다. At this time, the cooling is preferably performed by a water spray method.

또한, 상기 템퍼링은 720~750℃에서 수행되는 것이 바람직하다.
In addition, the above tempering is preferably performed at 720 to 750 ° C.

상기 목적을 달성하기 위한 본 발명의 실시예에 따른 발전설비용 부품은 중량%로, 탄소(C) : 0.16~0.18%, 실리콘(Si): 0.3~0.4%, 망간(Mn) : 0.6~0.8%, 인(P) : 0.001~0.015%, 황(S) : 0.001~0.008%, 알루미늄(Al) : 0.001~0.035%, 니켈(Ni) : 0.55~0.75%, 크롬(Cr) : 1.35~1.45%, 몰리브덴(Mo) : 0.95~1.05%, 바나듐(V) : 0.2~0.3% 및 나머지 철(Fe)과 불가피한 불순물로 이루어지고, 베이나이트 및 마르텐사이트 분율이 면적률로 90% 이상인 미세조직을 갖는 것을 특징으로 한다. In order to achieve the above object, a power plant component according to an embodiment of the present invention comprises 0.16 to 0.18% of carbon (C), 0.3 to 0.4% of silicon (Si), 0.6 to 0.8 of manganese (Mn) 0.001 to 0.015% of phosphorus (P), 0.001 to 0.008% of sulfur (S), 0.001 to 0.035% of aluminum (Al), 0.55 to 0.75% of nickel (Ni) (Fe) and inevitable impurities, wherein the bainite and martensite fractions are 90% or more in area ratio, and the content of bainite and martensite is 90% or more .

이때, 상기 발전설비용 부품은 상온에서 샤르피 평균충격흡수에너지가 30J 이상을 나타낼 수 있다. At this time, the component for power generation facilities may have a Charpy average impact absorption energy of 30J or more at room temperature.

또한, 상기 발전설비용 부품은 인장강도 570~780MPa, 항복강도 440MPa 이상 및 연신율 15% 이상을 나타낼 수 있다.
The parts for power generation facilities may exhibit a tensile strength of 570 to 780 MPa, a yield strength of 440 MPa or more, and an elongation of 15% or more.

본 발명에 따른 발전설비용 부품은 니켈, 크롬, 몰리브덴 등의 합금성분 조절 및 노말라이징 후 냉각속도 등의 공정 제어를 통하여 베이나이트와 마르텐사이트로 이루어지는 과냉조직을 면적률로 90% 이상 포함하면서도 우수한 충격 특성을 통하여 크랙발생을 억제할 수 있는 장점이 있다.
The parts for power generation facilities according to the present invention are characterized in that the supercooled structure composed of bainite and martensite is contained in an area ratio of 90% or more while controlling the alloy components such as nickel, chromium, molybdenum and the like, Cracks can be suppressed through the impact characteristics.

도 1은 본 발명의 실시예에 따른 발전설비용 부품 제조 방법을 개략적으로 나타낸 것이다. 나타내는 순서도이다.
도 2 내지 도 7은 시편 1~6의 미세조직을 나타낸 것이다.
1 schematically shows a method of manufacturing parts for power generation facilities according to an embodiment of the present invention. Fig.
Figs. 2 to 7 show the microstructure of specimens 1 to 6. Fig.

본 발명의 이점 및 특징, 그리고 그것들을 달성하는 방법은 첨부되는 도면과 함께 상세하게 후술되어 있는 실시예들을 참조하면 명확해질 것이다. 그러나, 본 발명은 이하에서 개시되는 실시예들에 한정되는 것이 아니라 서로 다른 다양한 형태로 구현될 것이며, 단지 본 실시예들은 본 발명의 개시가 완전하도록 하며, 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자에게 발명의 범주를 완전하게 알려주기 위해 제공되는 것이며, 본 발명은 청구항의 범주에 의해 정의될 뿐이다. BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

이하 첨부된 도면을 참조하여 본 발명의 바람직한 실시예에 따른 발전설비용 부품 및 그 제조 방법에 관하여 상세히 설명하면 다음과 같다.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a power plant component and a method of manufacturing the same according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

발전설비용 부품Components for power generation facilities

본 발명에 따른 발전설비용 부품은 대표적으로 터빈하우징이 될 수 있다. The parts for power plant according to the present invention can be typically a turbine housing.

본 발명에 따른 발전설비용 부품은 중량%로, 탄소(C) : 0.16~0.18%, 실리콘(Si): 0.3~0.4%, 망간(Mn) : 0.6~0.8%, 인(P) : 0.001~0.015%, 황(S) : 0.001~0.008%, 알루미늄(Al) : 0.001~0.035%, 니켈(Ni) : 0.55~0.75%, 크롬(Cr) : 1.35~1.45%, 몰리브덴(Mo) : 0.95~1.05%, 바나듐(V) : 0.2~0.3%를 포함한다. The parts for power generation facilities according to the present invention comprise 0.16 to 0.18% of carbon (C), 0.3 to 0.4% of silicon (Si), 0.6 to 0.8% of manganese (Mn) 0.001 to 0.008% of aluminum (Al), 0.001 to 0.035% of aluminum (Al), 0.55 to 0.75% of nickel (Ni), 1.35 to 1.45% of chromium (Cr) 1.05%, and vanadium (V): 0.2 to 0.3%.

상기 성분들 외 나머지는 철(Fe)과 제강 과정 등에서 불가피하게 포함되는 불순물이다. The rest of the above components are impurities inevitably included in iron (Fe) and steelmaking processes.

이하, 본 발명에 따른 발전설비용 부품에 포함되는 각 성분의 역할 및 함량에 대하여 설명하기로 한다.
Hereinafter, the role and content of each component included in the component for power generation facilities according to the present invention will be described.

탄소(C)Carbon (C)

본 발명에서 탄소(C)는 발전설비용 부품의 강도를 확보하기 위하여 첨가된다. In the present invention, carbon (C) is added in order to secure the strength of components for power generation facilities.

상기 탄소는 부품(강재) 전체 중량의 0.16~0.18중량%로 첨가되는 것이 바람직하다. 탄소의 첨가량이 0.16중량% 미만인 경우, 목표로 하는 강도 확보가 어렵다. 반대로, 탄소의 첨가량이 0.18중량%를 초과할 경우 탄화물 생성량 증가에 의하여 저온인성이 저하될 수 있다.
The carbon is preferably added in an amount of 0.16 to 0.18% by weight based on the total weight of the part (steel). When the addition amount of carbon is less than 0.16% by weight, it is difficult to secure a desired strength. On the contrary, when the amount of added carbon exceeds 0.18 wt%, the low temperature toughness may be lowered due to an increase in the amount of carbide production.

실리콘(Si)Silicon (Si)

본 발명에서 실리콘(Si)은 강 중의 산소를 제거하기 위한 탈산제로 첨가되며, 또한 고용 강화 효과를 향상시키는 역할을 한다. In the present invention, silicon (Si) is added as a deoxidizer to remove oxygen in the steel, and also serves to improve the solid solution strengthening effect.

상기 실리콘은 부품 전체 중량의 0.3~0.4중량%로 첨가되는 것이 바람직하다. 실리콘의 첨가량이 0.3중량% 미만일 경우 실리콘 첨가에 따른 탈산 효과 및 고용 강화 효과가 불충분하다. 반대로, 실리콘의 첨가량이 0.4중량%를 초과할 경우 강의 가공성을 저하시키는 문제점이 있다.
The silicon is preferably added in an amount of 0.3 to 0.4% by weight based on the total weight of the component. When the addition amount of silicon is less than 0.3% by weight, the deoxidation effect and the solid solution strengthening effect by the addition of silicon are insufficient. On the contrary, when the amount of silicon added exceeds 0.4% by weight, the workability of steel is deteriorated.

망간(Mn)Manganese (Mn)

본 발명에서 망간(Mn)은 고용강화 원소로써 매우 효과적이며 제조되는 발전설비용 부품의 강도 확보에 효과적인 원소이다. In the present invention, manganese (Mn) is a very effective element as a solid solution strengthening element, and is an effective element for securing the strength of parts for power generation facilities to be produced.

상기 망간은 부품 전체 중량의 0.6~0.8중량%로 첨가되는 것이 바람직하다. 망간의 첨가량이 0.6중량% 미만인 경우, 망간 첨가에 따른 고용강화 효과 및 강도 확보 효과가 불충분하다. 반대로, 망간의 첨가량이 0.8중량%를 초과할 경우, 인성을 악화시키는 문제점이 있다.
The manganese is preferably added in an amount of 0.6 to 0.8% by weight based on the total weight of the component. When the addition amount of manganese is less than 0.6% by weight, the effect of securing solubility and strengthening strength due to the addition of manganese is insufficient. On the other hand, when the addition amount of manganese exceeds 0.8% by weight, toughness is deteriorated.

인(P), 황(S)Phosphorus (P), sulfur (S)

인(P)은 입게 편석성 원소로서, 과다 함유되면 발전설비용 부품의 충격 특성을 저해하며, 가공 중 크랙을 유발한다. 이에 본 발명에서는 인의 함량을 부품 전체 중량의 0.015중량% 이하로 제한하였다. 다만, 인의 함량을 0.001중량% 미만의 극소로 제한하기는 어렵다. Phosphorus (P) is a segregating element, and if it is contained in excess, it impairs the impact characteristics of the parts for power generation facilities and causes cracks during processing. In the present invention, the content of phosphorus is limited to 0.015 wt% or less of the total weight of the parts. However, it is difficult to limit the phosphorus content to a minimum of less than 0.001% by weight.

황(S)이 과다하면 부품의 찢어짐을 유발하고, 표면 결함을 유발할 수 있다. 이에 본 발명에서는 황의 함량을 부품 전체 중량의 0.008중량% 이하로 제한하였다. 다만, 인의 함량을 0.001중량% 미만의 극소로 제한하기는 어렵다.
If sulfur (S) is excessive, tearing of the component may occur and surface defects may be caused. Therefore, in the present invention, the content of sulfur is limited to 0.008 wt% or less of the total weight of the parts. However, it is difficult to limit the phosphorus content to a minimum of less than 0.001% by weight.

알루미늄(Al)Aluminum (Al)

알루미늄(Al)은 우수한 탈산 효과를 제공하며, 또한 질소(N)와 결합하여 입자미세화에 기여한다. Aluminum (Al) provides an excellent deoxidizing effect and also contributes to particle refinement by bonding with nitrogen (N).

상기 알루미늄은 부품 전체 중량의 0.001~0.035중량%로 첨가되는 것이 바람직하다. 알루미늄의 첨가량이 0.001중량% 미만일 경우, 상기의 알루미늄 첨가 효과를 충분히 발휘하기 어렵다. 반대로, 알루미늄의 첨가량이 0.035중량%를 초과하는 경우, Al2O3를 과다하게 생성할 수 있다.
The aluminum is preferably added in an amount of 0.001 to 0.035% by weight based on the total weight of the component. When the addition amount of aluminum is less than 0.001% by weight, it is difficult to sufficiently exert the aforementioned effect of aluminum addition. On the contrary, when the added amount of aluminum exceeds 0.035% by weight, Al 2 O 3 can be excessively produced.

니켈(Ni)Nickel (Ni)

니켈(Ni)은 조직미세화 및 고용강화를 통하여 발전설비용 부품의 강도 향상에 기여하며, 저온인성을 향상시키는 역할을 한다.Nickel (Ni) contributes to the improvement of the strength of parts for power generation facilities through microstructure and strengthening of solid solution, and plays a role of improving low temperature toughness.

상기 니켈은 부품 전체 중량의 0.55~0.75중량%로 첨가되는 것이 바람직하다. 니켈의 첨가량이 0.55중량% 미만일 경우, 그 첨가 효과가 불충분하다. 반대로, 니켈의 첨가량이 0.75중량%를 초과하는 경우, 부품 제조 비용을 크게 상승시킬 수 있다.
The nickel is preferably added in an amount of 0.55 to 0.75% by weight based on the total weight of the component. When the addition amount of nickel is less than 0.55% by weight, the effect of addition is insufficient. On the contrary, when the addition amount of nickel is more than 0.75% by weight, the manufacturing cost of parts can be greatly increased.

크롬(Cr)Chromium (Cr)

크롬(Cr)은 경화능 향상 원소로 첨가되어 강도 향상에 기여한다. Chromium (Cr) is added as an element for improving hardenability and contributes to the improvement of strength.

상기 크롬은 부품 전체 중량의 1.35~1.45중량%로 첨가되는 것이 바람직하다. 크롬의 첨가량이 1.35중량% 미만일 경우 강도 향상 효과가 미미하다. 반대로, 크롬의 첨가량이 1.45중량%를 초과하는 경우, 가공성이 저하되는 문제점이 있다.
The chromium is preferably added in an amount of 1.35 to 1.45% by weight based on the total weight of the component. When the addition amount of chromium is less than 1.35 wt%, the strength improvement effect is insignificant. On the contrary, when the addition amount of chromium exceeds 1.45% by weight, there is a problem that the workability is lowered.

몰리브덴(Mo)Molybdenum (Mo)

몰리브덴(Mo)은 소입성 원소로 첨가되어 강도 향상에 기여한다. Molybdenum (Mo) is added as an ingot element and contributes to strength improvement.

상기 몰리브덴은 부품 전체 중량의 0.95~1.05중량%로 첨가되는 것이 바람직하다. 몰리브덴의 첨가량이 0.95중량% 미만일 경우, 그 첨가 효과가 불충분하다. 반대로, 몰리브덴의 첨가량이 1.05중량%를 초과할 경우, 부품 제조 비용을 크게 상승시킬 수 있다.
The molybdenum is preferably added in an amount of 0.95 to 1.05% by weight based on the total weight of the component. When the addition amount of molybdenum is less than 0.95% by weight, the effect of the addition is insufficient. On the other hand, if the addition amount of molybdenum exceeds 1.05% by weight, the manufacturing cost of parts can be greatly increased.

바나듐(V)Vanadium (V)

바나듐(V)은 바나듐계 탄질화물 석출물을 형성하여 강도를 향상시키는 역할을 한다. The vanadium (V) serves to improve the strength by forming a vanadium-based carbonitride precipitate.

상기 바나듐은 부품 전체 중량의 0.2~0.3%중량%로 첨가되는 것이 바람직하다. 바나듐의 첨가량이 0.2중량% 미만일 경우, 석출 강화 효과가 불충분하다. 반대로, 바나듐의 첨가량이 0.3중량%를 초과하는 경우에는 충격 특성이 크게 저하될 수 있다.
The vanadium is preferably added in an amount of 0.2 to 0.3% by weight based on the total weight of the component. When the addition amount of vanadium is less than 0.2% by weight, the precipitation strengthening effect is insufficient. On the contrary, when the addition amount of vanadium exceeds 0.3% by weight, the impact characteristics may be greatly reduced.

상기한 합금성분을 갖는 본 발명에 따른 발전설비용 부품은 후술하는 제조 공정에 의해, 베이나이트 및 마르텐사이트 분율이 면적률로 90% 이상인 미세조직을 가질 수 있다. 나머지는 페라이트, 펄라이트 등이 될 수 있다. The component for power generation facilities according to the present invention having the above-described alloy component can have a microstructure in which the bainite and martensite fractions are 90% or more in area ratio by a manufacturing process described later. And the remainder may be ferrite, pearlite, or the like.

또한, 본 발명에 따른 발전설비용 부품은 상기와 같은 높은 분율의 과냉 조직을 가지면서도, 상온에서 샤르피 평균충격흡수에너지가 30J 이상을 나타낼 수 있어, 충격 특성 또한 우수하다. In addition, the component for power generation facilities according to the present invention has a Charpy average impact absorption energy of 30 J or more at room temperature, while having a supercooled structure with a high fraction as described above, and also has excellent impact characteristics.

나아가, 본 발명에 따른 발전설비용 부품은 인장강도 570~780MPa, 항복강도 440MPa 이상 및 연신율 15% 이상을 나타낼 수 있다.
Further, the parts for power plant according to the present invention may exhibit a tensile strength of 570 to 780 MPa, a yield strength of 440 MPa or more, and an elongation of 15% or more.

발전설비용 부품 제조 방법Manufacturing method of components for power generation facilities

도 1은 본 발명의 실시예에 따른 발전설비용 부품 제조 방법을 나타내는 순서도이다.1 is a flowchart showing a method of manufacturing a component for power generation facilities according to an embodiment of the present invention.

도 1을 참조하면, 도시된 발전설비용 부품 제조 방법은 주조 단계(S110), 노말라이징 단계(S120), 냉각 단계(S130) 및 템퍼링 단계(S140)를 포함한다.Referring to FIG. 1, the illustrated method for manufacturing parts for power generation facilities includes a casting step S110, a normalizing step S120, a cooling step S130, and a tempering step S140.

주조 단계(S110)에서는 전술한 합금성분으로 이루어진 용탕을 주형 내에 투입하여 응고한다. In the casting step (S110), the molten metal of the above-mentioned alloy component is put into a mold and solidified.

노말라이징 단계(S120)에서는 응고된 결과물을 Ac3 이상의 온도, 보다 구체적으로는 930~960℃ 정도의 온도에서 대략 4~8시간동안 노말라이징 처리하여 결정립을 미세화하고, 균질화한다. In the normalizing step (S120), the solidified product is subjected to a normalizing treatment at a temperature of Ac3 or higher, more specifically about 930 to 960 ° C for about 4 to 8 hours to refine the crystal grains and homogenize them.

냉각 단계(S130)에서는 노말라이징 처리된 결과물을 냉각한다. In the cooling step (S130), the result of the normalizing treatment is cooled.

이때, 냉각은 0.25~0.40℃/sec의 평균냉각속도로 수행되는 것이 바람직하다. 냉각속도가 0.25℃/sec 미만에서는 충분한 과냉 조직 형성이 어렵다. 반대로, 냉각속도가 0.40℃/sec를 초과하는 경우, 열응력에 의하여 부품에 크랙이 발생할 수 있다. At this time, cooling is preferably performed at an average cooling rate of 0.25 to 0.40 ° C / sec. When the cooling rate is less than 0.25 DEG C / sec, it is difficult to form a sufficient supercooled structure. On the other hand, when the cooling rate exceeds 0.40 DEG C / sec, cracks may occur in the component due to thermal stress.

이러한 0.25~0.40℃/sec의 평균냉각속도를 달성하기 위하여, 워터 스프레이(water spray)를 이용한 냉각 방식이 바람직하다. 공냉의 경우, 0.02℃/sec 정도로 냉각속도가 너무 느리고, 수냉의 경우, 1℃/sec 이상으로 냉각속도가 너무 빠르나, 워터 스프레이에 의한 냉각 방식을 이용한 결과, 상기와 같은 0.25~0.40℃/sec의 평균냉각속도를 달성할 수 있었다. In order to achieve the average cooling rate of 0.25 to 0.40 DEG C / sec, a cooling method using water spray is preferable. In the case of air cooling, the cooling rate is too slow at about 0.02 ° C / sec. In the case of water cooling, the cooling rate is too fast at 1 ° C / sec or more. As a result of using the cooling method using water spray, The average cooling rate of the cooling water can be achieved.

템퍼링 단계(S140)에서는 노말라이징된 결과물을 템퍼링하여 강도와 연신율 밸런스를 조절한다. In the tempering step (S140), the normalized resultant is tempered to adjust the strength and elongation balance.

이때, 템퍼링은 720~750℃에서 대략 4~8시간동안 수행되는 것이 바람직하다. 템퍼링 온도가 720℃ 미만일 경우, 템퍼링에 의한 강도와 연신율 밸런스 조절 효과가 불충분하다. 반면, 템퍼링 온도가 750℃를 초과하는 경우, 강도가 지나치게 낮아지는 문제점이 있다.
At this time, the tempering is preferably performed at 720 to 750 ° C for about 4 to 8 hours. When the tempering temperature is less than 720 占 폚, the effect of tempering and balance of elongation adjustment is insufficient. On the other hand, when the tempering temperature exceeds 750 캜, there is a problem that the strength becomes too low.

실시예Example

이하, 본 발명의 바람직한 실시예를 통해 본 발명의 구성 및 작용을 더욱 상세히 설명하기로 한다. 다만, 이는 본 발명의 바람직한 예시로 제시된 것이며 어떠한 의미로도 이에 의해 본 발명이 제한되는 것으로 해석될 수는 없다. Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

여기에 기재되지 않은 내용은 이 기술 분야에서 숙련된 자이면 충분히 기술적으로 유추할 수 있는 것이므로 그 설명을 생략하기로 한다.
The contents not described here are sufficiently technically inferior to those skilled in the art, and a description thereof will be omitted.

1. 시편의 제조1. Preparation of specimens

표 1에 기재된 합금성분과, 각각 중량%로, C : 0.17%, Si : 0.35%, Mn : 0.7%, P : 0.01%, S : 0.005%, Al : 0.002%, V : 0.25%를 포함하고, 나머지가 철과 불가피한 불순물로 이루어진 용탕을 주형에 투입하여 자연냉각방식으로 응고한 후, 955℃에서 6시간동안 노말라이징 처리하였다.The alloy composition described in Table 1 contains 0.17% of C, 0.35% of Si, 0.7% of Mn, 0.01% of P, 0.005% of S, 0.002% of Al and 0.25% of V, And the remainder of iron and unavoidable impurities were put into a mold and solidified by a natural cooling method and then subjected to normalizing treatment at 955 ° C for 6 hours.

이후, 표 1에 기재된 방법으로 냉각(공냉의 경우 0.02℃/sec, 스프레이 냉각의 경우 0.30℃/sec)한 후, 표 1에 기재된 온도에서 6시간동안 템퍼링한 후, 공냉하여 시편 1~6을 제조하였다. Thereafter, they were cooled (0.02 ° C / sec in the case of air cooling and 0.30 ° C / sec in the case of spray cooling) by the method described in Table 1, tempered for 6 hours at the temperature shown in Table 1, .

표 1에서 각 시편이 도 2 ~ 도 7에 도시된 미세조직 사진(도 2: 시편 1, 도 3: 시편 2 …, 도 7: 시편 6)을 토대로 베이나이트와 마르텐사이트가 면적률로 90% 이상일 경우 "O"로 표시하고, 그렇지 않을 경우 "X"로 표시하였다. Based on the microstructure photographs (FIG. 2: PES 1, FIG. 3: PES 2,..., And PES 7: PES 6) shown in FIGS. 2 to 7 in Table 1, bainite and martensite have an area ratio of 90% Or more, it is marked with "O", otherwise it is marked with "X".

[표 1][Table 1]

Figure pat00001
Figure pat00001

표 1을 참조하면, 본 발명에서 제시한 합금성분 및 공정조건을 만족하는 시편 4, 6의 경우, 과냉조직이 90% 이상인 미세조직을 가지면서 아울러 샤르피충격흡수에너지(CVN)가 30J 이상을 나타내었다. Referring to Table 1, in the case of the specimens 4 and 6 satisfying the alloy component and the process conditions proposed in the present invention, the supercooled structure had a microstructure of 90% or more and a Charpy impact absorption energy (CVN) of 30 J or more .

이에 반하여, 본 발명에서 제시한 합금성분범위를 벗어나는 시편 1,2, 그리고, 공냉 방법 및 낮은 템퍼링 온도가 적용된 시편 1,2,3의 경우 충격흡수 에너지가 목표치에 미치지 못하였다. On the other hand, the impact absorption energy of the specimens 1 and 2 deviating from the alloy composition range proposed in the present invention and the specimens 1, 2 and 3 to which the air cooling method and the low tempering temperature were applied, were below the target values.

또한, 템퍼링 온도가 상대적으로 낮은 시편 5의 경우, 인장강도가 지나치게 높은 반면, 충격흡수에너지가 상대적으로 낮았다.
In the case of the specimen 5 having a relatively low tempering temperature, the tensile strength was excessively high while the impact absorption energy was relatively low.

이상에서는 본 발명의 실시예를 중심으로 설명하였지만, 당업자의 수준에서 다양한 변경이나 변형을 가할 수 있다. 이러한 변경과 변형이 본 발명의 범위를 벗어나지 않는 한 본 발명에 속한다고 할 수 있다. 따라서 본 발명의 권리범위는 이하에 기재되는 청구범위에 의해 판단되어야 할 것이다. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. Such changes and modifications are intended to fall within the scope of the present invention unless they depart from the scope of the present invention. Accordingly, the scope of the present invention should be determined by the following claims.

Claims (6)

중량%로, 탄소(C) : 0.16~0.18%, 실리콘(Si): 0.3~0.4%, 망간(Mn) : 0.6~0.8%, 인(P) : 0.001~0.015%, 황(S) : 0.001~0.008%, 알루미늄(Al) : 0.001~0.035%, 니켈(Ni) : 0.55~0.75%, 크롬(Cr) : 1.35~1.45%, 몰리브덴(Mo) : 0.95~1.05%, 바나듐(V) : 0.2~0.3% 및 나머지 철(Fe)과 불가피한 불순물로 이루어진 용탕을 주형 내에 투입하여 응고하는 단계;
상기 응고된 결과물을 Ac3 이상의 온도에서 노말라이징 처리하는 단계;
상기 노말라이징 처리된 결과물을 냉각하는 단계; 및
상기 노말라이징된 결과물을 템퍼링하는 단계;를 포함하고,
상기 냉각은 0.25~0.40℃/sec의 평균냉각속도로 수행되는 것을 특징으로 하는 발전설비용 부품 제조 방법.
(Si): 0.3 to 0.4%, manganese (Mn): 0.6 to 0.8%, phosphorus (P): 0.001 to 0.015%, sulfur (S): 0.001 0.005 to 0.75% of nickel (Ni), 1.35 to 1.45% of chromium (Cr), 0.95 to 1.05% of molybdenum (Mo), 0.2 ~ 0.3% and the remaining iron (Fe) and inevitable impurities into a mold to solidify the molten metal;
Subjecting the solidified product to a normalizing treatment at a temperature of Ac3 or higher;
Cooling the resulting normalized product; And
And tempering the normalized resultant,
Wherein the cooling is performed at an average cooling rate of 0.25 to 0.40 DEG C / sec.
제1항에 있어서,
상기 냉각은 워터 스프레이(water spray) 방식으로 수행되는 것을 특징으로 하는 발전설비용 부품 제조 방법.
The method according to claim 1,
Wherein the cooling is performed by a water spray method.
제1항에 있어서,
상기 템퍼링은 720~750℃에서 수행되는 것을 특징으로 하는 발전설비용 부품 제조 방법.
The method according to claim 1,
Wherein the tempering is performed at 720 to 750 占 폚.
중량%로, 탄소(C) : 0.16~0.18%, 실리콘(Si): 0.3~0.4%, 망간(Mn) : 0.6~0.8%, 인(P) : 0.001~0.015%, 황(S) : 0.001~0.008%, 알루미늄(Al) : 0.001~0.035%, 니켈(Ni) : 0.55~0.75%, 크롬(Cr) : 1.35~1.45%, 몰리브덴(Mo) : 0.95~1.05%, 바나듐(V) : 0.2~0.3% 및 나머지 철(Fe)과 불가피한 불순물로 이루어지고,
베이나이트 및 마르텐사이트 분율이 면적률로 90% 이상인 미세조직을 갖는 발전설비용 부품.
(Si): 0.3 to 0.4%, manganese (Mn): 0.6 to 0.8%, phosphorus (P): 0.001 to 0.015%, sulfur (S): 0.001 0.005 to 0.75% of nickel (Ni), 1.35 to 1.45% of chromium (Cr), 0.95 to 1.05% of molybdenum (Mo), 0.2 ~ 0.3% and the balance iron (Fe) and inevitable impurities,
Parts for power generation facilities having a microstructure in which the bainite and martensite fractions are 90% or more in area ratio.
제4항에 있어서,
상기 발전설비용 부품은
상온에서 샤르피 평균충격흡수에너지가 30J 이상인 것을 특징으로 하는 발전설비용 부품.
5. The method of claim 4,
The power plant component
And a Charpy average impact absorption energy of 30 J or more at room temperature.
제4항에 있어서,
상기 발전설비용 부품은
인장강도 570~780MPa, 항복강도 440MPa 이상 및 연신율 15% 이상을 나타내는 것을 특징으로 하는 발전설비용 부품.5. The method of claim 4,
The power plant component
A tensile strength of 570 to 780 MPa, a yield strength of 440 MPa or more, and an elongation of 15% or more.
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