WO2020141810A1 - Nitrided surface structure of high-power and high-temperature engine valve stem, and surface nitriding method - Google Patents

Nitrided surface structure of high-power and high-temperature engine valve stem, and surface nitriding method Download PDF

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Publication number
WO2020141810A1
WO2020141810A1 PCT/KR2019/018579 KR2019018579W WO2020141810A1 WO 2020141810 A1 WO2020141810 A1 WO 2020141810A1 KR 2019018579 W KR2019018579 W KR 2019018579W WO 2020141810 A1 WO2020141810 A1 WO 2020141810A1
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Prior art keywords
valve
stem
layer
power
stem portion
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PCT/KR2019/018579
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French (fr)
Korean (ko)
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손현조
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안전공업 주식회사
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/80—After-treatment
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/24—Nitriding
    • C23C8/26—Nitriding of ferrous surfaces
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/40—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using liquids, e.g. salt baths, liquid suspensions
    • C23C8/42—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using liquids, e.g. salt baths, liquid suspensions only one element being applied
    • C23C8/48—Nitriding
    • C23C8/50—Nitriding of ferrous surfaces
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L3/00—Lift-valve, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces; Parts or accessories thereof
    • F01L3/02—Selecting particular materials for valve-members or valve-seats; Valve-members or valve-seats composed of two or more materials
    • F01L3/04—Coated valve members or valve-seats
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L2303/00—Manufacturing of components used in valve arrangements

Definitions

  • the present invention relates to a surface nitriding structure and a surface nitriding treatment method of a stem part of a valve for a high-power and high-temperature engine, and more specifically, a surface nitriding layer of a stem part of a valve for a high-power and high-temperature engine is cured and a base material according to nitriding diffusion at a high temperature.
  • the present invention relates to a surface nitriding structure and a surface nitriding treatment method of a stem part of a valve for a high-power and high-temperature engine with improved durability.
  • an intake/exhaust valve of a valve system for an automobile engine is a component that opens and closes a combustion chamber of an engine by reciprocating up and down according to a rotational motion of a camshaft.
  • the intake valve is a valve that opens and closes the intake port of the engine so that a mixture of fuel and air is supplied to the combustion chamber at an appropriate time
  • the exhaust valve is a valve that opens and closes the exhaust port so that combustion gas can be discharged at an appropriate time in the combustion chamber.
  • the intake/exhaust valve is inserted into the hollow valve guide fixed to each port to reciprocate, and the valve guide guides the reciprocation of the valve in contact with the stem portion of the valve.
  • the reciprocating valve is surface-treated for abrasion of the engine valve shaft, and two methods are mainly applied by hard chromium (Cr) plating and surface nitriding (softening method).
  • Chromium plating has the advantage of excellent abrasion resistance, lubricity, heat resistance, corrosion resistance, etc., but chromium produced from natural minerals is depleted and has high scarcity value, resulting in high price, and various harmful components. There were implied problems.
  • chromium plating was treated while heating an aqueous solution of hexavalent chromium to convert to trivalent chromium, but in the process of heating, a small amount of hexavalent chromium is included in the vapor and accumulates in the human body during the breathing process. It also acted as the cause of osteoporosis and various diseases. In addition, chromium also acted as a cause of environmental problems contaminating the surrounding soil.
  • the surface nitridation (soft nitridation method) is K2CO3 and KCNO as the main components and is obtained through chemical reactions, so it has the advantage of easy price fluctuation and infinite production, so Korea and Japan are producing valves by the above surface nitridation. .
  • surface nitridation (soft nitridation) is accompanied by the generation of highly toxic KCN, but is not accumulated in the human body and is known to be not harmful to the human body even after prolonged contact.
  • the shaft portion 32 is formed so that the molded engine valve 30 has a constant length.
  • a coating layer is formed on the surface of the base material 13 of the stem portion 11 in Korean Patent Registration No. 10-1337936 (date of registration December 2, 2013), and the coating layer is coated on the surface of the base material 13 as the lowest layer.
  • a buffer layer 14 made of Ti or Cr;
  • a valve for an engine is known, comprising a TiAlCN layer (17) coated on the TiAlN/CrN nanomultilayer (16).
  • Korean Patent Publication No. 10-2013-0099763 (published on September 6, 2013) is coated on the surface of the stem portion 11 as the bottom layer and a buffer layer 14 made of Ti or Cr; An intermediate layer 16 coated on the buffer layer 14 and made of CrN or TiN or TiCN; A TiAlN/CrN first nano layer 16 coated on the intermediate layer 15; And a TiAlCN/CrCN second nanolayer 17 coated as the top layer on the TiAlN/CrN first nanolayer 16; Valves for engines are known, which have a coating layer comprising a.
  • the surface nitriding layer of the stem portion of the valve for high power and high temperature engines is cracked in the header portion and the stem portion of the valve by curing and curing of the base material due to nitridation diffusion at high temperature.
  • the surface nitridation structure of the high power and high temperature engine valve which improves durability by removing the surface nitridation layer in the section exposed to high temperature between the header and stem parts of the valve, and It is a technical problem to provide a surface nitriding treatment method.
  • the surface nitriding layer is a header portion of a valve exposed to high temperatures of 750° C. or higher among the stem portions, and
  • the surface nitriding structure of the stem portion of the valve for high power and high temperature engines, which is removed between the stem portions, is a technical solution.
  • the portion between the header portion and the stem portion from which the surface nitride layer has been removed is an interval of 11 to 25 mm spaced from the end of the header portion toward the stem portion.
  • the present invention provides a method for treating a surface of a stem portion of a high power and high temperature engine valve, comprising: forming a surface nitride layer on the valve stem of the engine; And removing the surface nitridation layer between the header portion and the stem portion of the valve exposed to high temperatures of 750°C or higher among the stem portions; technically solving the method of treating the surface portion of the stem portion of the valve for high power and high temperature engines, including Do it in a way.
  • the portion between the header portion and the stem portion of the valve removing the surface nitridation layer is spaced 11 to 25 mm apart from the end of the header portion toward the stem portion.
  • the gap part is considered as a technical solution.
  • the removal of the surface nitride layer is a technical solution to be removed by polishing.
  • the surface nitridation structure and surface nitridation treatment method of the high power and high temperature engine valve of the present invention remove the surface nitridation layer of the section exposed to high temperature between the header and stem parts of the high power and high temperature engine valve, thereby
  • the surface nitridation layer between the header part and the stem part prevents degradation of durability, such as cracking and cracking between the header part and the stem part of the valve due to hardening due to nitridation diffusion at high temperature and generation of pores in the base material. It has an excellent effect, and has a breakthrough effect that can occupy a technological advantage over Japan, which is an automobile powerhouse, for high-power and high-temperature engine valves.
  • Figure 2 is a comparison of the results of the pore generation time of the base material according to the diffusion of nitride
  • Figure 3 is a comparison of the results of high temperature fatigue life test before and after removing the surface nitride layer
  • the present invention in the high-power and high-temperature engine valve having a surface nitride layer formed on the valve stem portion for the engine, the surface nitride layer is removed between the header portion and the stem portion of the valve exposed to high temperatures of 750 °C or more of the stem portion.
  • the surface nitriding structure of the stem portion of the valve for high-power and high-temperature engines which is characterized in that it is characterized by the technical composition.
  • the portion between the header portion and the stem portion from which the surface nitride layer has been removed is characterized by a technical configuration that is a gap portion spaced 11 to 25 mm from the end of the header portion toward the stem portion.
  • the present invention provides a method for treating a surface of a stem portion of a high power and high temperature engine valve, comprising: forming a surface nitride layer on the valve stem of the engine; And removing the surface nitridation layer between the header portion and the stem portion of the valve exposed to high temperatures of 750°C or higher among the stem portions; the technical configuration of the method for treating the surface portion of the stem portion of the valve for high power and high temperature engines comprising It is characterized by.
  • the portion between the header portion and the stem portion of the valve removing the surface nitridation layer is spaced 11 to 25 mm apart from the end of the header portion toward the stem portion.
  • the gap is characterized by the technical composition.
  • the removal of the surface nitride layer is characterized by a technical configuration that is removed by polishing.
  • the surface nitriding structure of the stem portion of the high power and high temperature engine valve of the present invention is a high power and high temperature engine valve having a surface nitridation layer formed on the valve stem portion of the engine, wherein the surface nitridation layer is at least 750°C high in the stem portion It is configured to be removed between the header portion and the stem portion of the valve exposed to.
  • the temperature distribution of the valve stem portion exposed to the combustion chamber in the low power (MPI) engine operated at less than about 700° C. and the high power (T-GDI) engine operated at high power and high temperature is low power (MPI).
  • MPI low power
  • the surface nitridation layer of the low-output (MPI) engine valve stem portion operated at about 600 to 700°C does not have a large change (A) in the diffusion thickness of nitride, pores are generated in the base material according to diffusion of nitride.
  • the surface nitridation layer of the high-power (T-GDI) engine valve stem portion operated at 750°C or higher has a large change (A) in the diffusion thickness of nitride, so that pores are severely generated in the base material according to the diffusion of nitride.
  • a white layer and a black layer thereon are formed on the surface from low power 700° C. (150 hrs) and high power 750° C. (100 hrs), and the combination of Fe 3 N or Fe 4 N as the nitride layer diffuses in the depth direction. Since the pores are formed in the cracked surface layer, it is possible to confirm the occurrence of pores in the base material due to high temperature exposure.
  • the portion between the header portion and the stem portion from which the surface nitride layer is removed is preferably designed to be spaced apart 11 to 25 mm from the end of the header portion toward the stem portion.
  • the method for treating the surface of the stem portion of the high power and high temperature engine valve of the present invention includes forming a surface nitride layer on the valve stem portion for the engine; And removing the surface nitride layer between the stem portion and the stem portion of the valve exposed to high temperatures of 750°C or higher among the stem portions.
  • the portion between the header portion and the stem portion of the valve for removing the surface nitride layer is 11-25 mm from the end of the header portion toward the stem portion. It is desirable to design with spaced apart parts.
  • the removal of the surface nitride layer in the step of removing the surface nitride layer may be removed by polishing.
  • the surface nitridation structure and surface nitridation treatment method of the high power and high temperature engine valve of the present invention remove the surface nitridation layer of the section exposed to high temperature between the header and stem parts of the high power and high temperature engine valve, thereby
  • the surface nitridation layer between the header part and the stem part prevents degradation of durability, such as cracking and cracking between the header part and the stem part of the valve due to hardening due to nitridation diffusion at high temperature and generation of pores in the base material.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)

Abstract

The present invention relates to a nitrided surface structure of a high-power and high-temperature engine valve stem, and a surface nitriding method and, more specifically, to: a nitrided surface structure of a high-power and high-temperature engine valve stem, the nitrided surface structure being for preventing durability deterioration, such as that of crack formation between the header and stem of a valve and breaking, caused by pores to be formed on a base material through nitriding diffusion at a high temperature on a nitrided surface layer of a high-power and high-temperature engine valve stem, so as to remove a nitrided surface layer in the section, exposed to a high temperature, between the header and stem of the valve, thereby improving durability; and a surface nitriding method.

Description

고출력 및 고온 엔진용 밸브의 스템부 표면질화 구조 및 표면질화 처리방법Surface nitriding structure and surface nitriding treatment method of high power and high temperature engine valve stem
본 발명은 고출력 및 고온 엔진용 밸브의 스템부 표면질화 구조 및 표면질화 처리방법에 관한 것으로, 보다 상세하게는 고출력 및 고온 엔진용 밸브의 스템부 표면질화층이 고온에서 질화확산에 따른 경화 및 모재의 기공발생에 의하여 밸브의 헤더부 및 스템부 사이부분에 크랙이 발생하고, 부러지는 등 내구성능 저하를 방지하기 위하여 밸브의 헤더부 및 스템부 사이의 고온에 노출되는 구간의 표면질화층을 제거하여 내구성능을 향상시킨 고출력 및 고온 엔진용 밸브의 스템부 표면질화 구조 및 표면질화 처리방법에 관한 것이다.The present invention relates to a surface nitriding structure and a surface nitriding treatment method of a stem part of a valve for a high-power and high-temperature engine, and more specifically, a surface nitriding layer of a stem part of a valve for a high-power and high-temperature engine is cured and a base material according to nitriding diffusion at a high temperature. Removes the surface nitridation layer in the section exposed to high temperature between the header and the stem of the valve to prevent deterioration of durability, such as cracks and cracks between the header and the stem of the valve due to the occurrence of pores Therefore, the present invention relates to a surface nitriding structure and a surface nitriding treatment method of a stem part of a valve for a high-power and high-temperature engine with improved durability.
일반적으로, 자동차 엔진용 밸브 시스템의 흡/배기밸브는 캠 샤프트의 회전운동에 따라 상하 왕복운동을하여 엔진의 연소실을 개폐하는 부품이다.In general, an intake/exhaust valve of a valve system for an automobile engine is a component that opens and closes a combustion chamber of an engine by reciprocating up and down according to a rotational motion of a camshaft.
흡기밸브는 연료와 공기의 혼합기가 적정 시점에 연소실에 공급되도록 엔진의 흡기포트를 개폐하는 밸브이고, 배기밸브는 연소실에서 연소가스가 적정 시점에서 배출될 수 있도록 배기포트를 개폐하는 밸브이다.The intake valve is a valve that opens and closes the intake port of the engine so that a mixture of fuel and air is supplied to the combustion chamber at an appropriate time, and the exhaust valve is a valve that opens and closes the exhaust port so that combustion gas can be discharged at an appropriate time in the combustion chamber.
이러한 흡/배기밸브는 각 포트에 고정된 중공의 밸브 가이드 내측에 삽입되어 왕복운동을 하게 되며, 이때 밸브가이드는 밸브의 스템부에 접촉된 상태로 밸브의 왕복운동을 가이드 하게 된다.The intake/exhaust valve is inserted into the hollow valve guide fixed to each port to reciprocate, and the valve guide guides the reciprocation of the valve in contact with the stem portion of the valve.
상기와 같이, 왕복운동을 하는 밸브는 엔진밸브 축부의 마모를 위한 표면처리를 하는데, 그 방법으로는 경질크롬(Cr) 도금과 표면질화(연질화법)에 의한 두 가지 방법이 주로 적용된다.As described above, the reciprocating valve is surface-treated for abrasion of the engine valve shaft, and two methods are mainly applied by hard chromium (Cr) plating and surface nitriding (softening method).
크롬 도금은 내마모성과, 윤활성, 내열성, 내식성 등이 우수한 장점이 있으나, 자연의 광물질에서 생산되는 크롬은 고갈상태로 진행되어 현재 희소가치가 높고, 그에 따른 가격이 상승되는 문제점이 있으며, 각종 유해성분이 내포된 문제점등이 있었다.Chromium plating has the advantage of excellent abrasion resistance, lubricity, heat resistance, corrosion resistance, etc., but chromium produced from natural minerals is depleted and has high scarcity value, resulting in high price, and various harmful components. There were implied problems.
즉, 크롬 도금은 6가 크롬의 수용액을 가열하여 3가 크롬으로 변환시키면서 처리하였으나, 가열하는 과정에서 미세량의 6가 크롬이 증기속에 포함되어 호흡하는 과정에서 인체 내로 들어가 축적되는 문제점이 있으며, 이는 골다공증 및 다양한 질환의 원인으로 작용되기도 하였다. 뿐만 아니라, 크롬은 주변 토양을 오염시키는 환경문제의 원인으로 작용되기도 하였다.That is, chromium plating was treated while heating an aqueous solution of hexavalent chromium to convert to trivalent chromium, but in the process of heating, a small amount of hexavalent chromium is included in the vapor and accumulates in the human body during the breathing process. It also acted as the cause of osteoporosis and various diseases. In addition, chromium also acted as a cause of environmental problems contaminating the surrounding soil.
반면, 표면질화(연질화법)는 K2CO3와 KCNO를 주성분으로 하며 화학반응을 통해 얻어지는 것으로, 가격변동이 쉽고, 무한 생산이 가능하다는 장점이 있으므로 우리나라 및 일본은 상기 표면질화에 의해 밸브를 생산하고 있다.On the other hand, the surface nitridation (soft nitridation method) is K2CO3 and KCNO as the main components and is obtained through chemical reactions, so it has the advantage of easy price fluctuation and infinite production, so Korea and Japan are producing valves by the above surface nitridation. .
또한, 표면질화(연질화법)는 독성이 강한 KCN의 발생이 수반되지만 인체에 축적되지 않으며 장시간 접촉해도 인체에 유해하지 않은 것으로 알려져있다.In addition, surface nitridation (soft nitridation) is accompanied by the generation of highly toxic KCN, but is not accumulated in the human body and is known to be not harmful to the human body even after prolonged contact.
종래 엔진밸브 축부의 표면처리방법을 살펴 보면, 한국공개특허 특1996-0029480(공개일자 1996년08월17일)에 축부(2)의 일단에 헤드부(1)를 보유하는 티탄 또는 티탄합금제 밸브체(3)에 있어서 적어도 밸브가이드(7)와 미끄럼접촉하는 외주면에, 철계재료로 이루어지는 피복층(4)을 형성한 후, 그 피복층에 질화처리를 실시하여 질화층(6)을 형성하는 것을 특징으로 하는 티탄 또는 티탄합금제 엔진밸브의 표면처리방법이 공지되어 있다.Looking at the surface treatment method of the conventional engine valve shaft, titanium or titanium alloy having a head portion 1 at one end of the shaft portion 2 in Korean Patent Publication No. 1996-0029480 (published on August 17, 1996) In the valve body 3, after forming a coating layer 4 made of an iron-based material on at least an outer circumferential surface in sliding contact with the valve guide 7, a nitriding treatment is performed on the coating layer to form a nitride layer 6 A surface treatment method of an engine valve made of titanium or titanium alloy is known.
또한, 한국등록특허 10-1071632(등록일자 2011년10월04일)에 최소 하나 이상의 코터홈이 형성된 엔진밸브의 표면처리 방법에 있어서, 성형된 엔진밸브(30)가 일정한 길이를 갖도록 축부(32) 전장을 절단하는 과정과(S110); 전장절단 후, 엔진밸브(30)의 축부(32) 외경을 그라인더로 연삭(황삭) 가공하는 축 조연 과정과(S120); 축 조연 후, 1500 ~ 1750rpm으로 고속 회전하는 한 쌍의 숫돌 사이에 엔진밸브(30)의 축부(32)를 위치시켜 정삭가공하는 축 사상 과정과(S130); 축 사상 후, 엔진밸브(30)를 550 ~ 590℃ 범위의 연질화 용액에 30 ~ 45분간 침지시켜 화학반응을 통해 질화층을 형성하는 연질화 과정과(S140); 연질화 과정 후, 엔진밸브(30)의 코터홈(33)이 형성된 축단부를 950 ~ 1050℃ 범위에서 15 ~ 3초간 고주파 열처리한 후 상온에서 공냉시키는 축 단부 열처리 과정과(S150); 축 단부 열처리과정 후, 코터홈(33)이 형성된 축단부를 180 ~ 250℃ 범위에서 15 ~ 3초간 중주파 열처리하는 축 단부 템퍼링 과정과(S160); 상기 축 단부 템퍼링 과정 후, 숫돌에 의한 연삭으로 코터홈(33)에 형성된 이물질 및 돌출부분을 제거하는 코터홈 연삭 과정과(S170); 코터홈 연삭 후, 엔진밸브(30)의 축부(32)를 숫돌로부터 실시되는 축 버핑을 통해 질화로부터 발생한 유해층을 제거하는 과정과(S180); 축 버핑 후, 엔진밸브(30)의 헤드부(31)에 형성된 밸브면(34)을 숫돌로 연마하는 밸브면 연마 과정과(S190); 벨브면 연마 후, 엔진밸브(30)를 세척하여 이물질을 제거하는 세척과정(S200);을 포함하여 이루어지는 것을 특징으로 하는 엔진밸브의 표면처리 방법이 공지되어 있다.In addition, in the surface treatment method of the engine valve having at least one coater groove formed in Korean Patent Registration No. 10-1071632 (registration date October 4, 2011), the shaft portion 32 is formed so that the molded engine valve 30 has a constant length. ) The process of cutting the electric field (S110); After the electric length cutting, the shaft forming process of grinding (roughing) the outer diameter of the shaft portion 32 of the engine valve 30 with a grinder (S120); After the shaft rolling, the shaft finishing process is performed by positioning the shaft portion 32 of the engine valve 30 between a pair of grinding wheels rotating at a high speed of 1500 to 1750 rpm (S130); After shafting, the softening process of forming a nitride layer through a chemical reaction by immersing the engine valve 30 in a softening solution in the range of 550 to 590°C for 30 to 45 minutes (S140); After the softening process, the shaft end heat treatment process of air-cooling at room temperature after high-frequency heat treatment for 15 to 3 seconds at a shaft end where the coater groove 33 of the engine valve 30 is formed in a range of 950 to 1050° C. (S150); After the shaft end heat treatment process, the shaft end tempering process for mid-frequency heat treatment for 15 to 3 seconds in the 180 to 250°C range of the shaft end where the coater groove 33 is formed (S160); After the shaft end tempering process, a coater groove grinding process for removing foreign substances and protrusions formed in the coater groove 33 by grinding with a grindstone (S170); After grinding the coater groove, the process of removing the harmful layer generated from nitriding through axial buffing of the shaft portion 32 of the engine valve 30 from a grindstone (S180); After the shaft buffing, the valve surface polishing process of grinding the valve surface 34 formed on the head portion 31 of the engine valve 30 with a whetstone (S190); After the valve surface is polished, a cleaning process (S200) in which the engine valve 30 is cleaned to remove foreign substances is known.
또한, 한국등록특허 10-1337936(등록일자 2013년12월02일)에 스템부(11)의 모재(13) 표면에 코팅층이 형성되고, 상기 코팅층은, 모재(13) 표면에 최하층으로서 코팅되고 Ti 또는 Cr로 이루어진 버퍼층(14)과; 상기 버퍼층(14) 위에 코팅되고 CrN, TiN, 또는 TiCN으로 이루어진 중간층(15)과; 상기 중간층(15) 위에 코팅되는 TiAlN/CrN 나노다층(16)과; 상기 TiAlN/CrN 나노다층(16) 위에 코팅되는 TiAlCN 층(17);을 포함하는 것을 특징으로 하는 엔진용 밸브가 공지되어 있다.In addition, a coating layer is formed on the surface of the base material 13 of the stem portion 11 in Korean Patent Registration No. 10-1337936 (date of registration December 2, 2013), and the coating layer is coated on the surface of the base material 13 as the lowest layer. A buffer layer 14 made of Ti or Cr; An intermediate layer 15 coated on the buffer layer 14 and made of CrN, TiN, or TiCN; A TiAlN/CrN nano-multilayer 16 coated on the intermediate layer 15; A valve for an engine is known, comprising a TiAlCN layer (17) coated on the TiAlN/CrN nanomultilayer (16).
또한, 한국공개특허 10-2013-0099763(공개일자 2013년09월06일)에 스템부(11)의 표면에 최하층으로서 코팅되고 Ti 또는 Cr로 이루어진 버퍼층(14); 상기 버퍼층(14) 위에 코팅되고 CrN 이나 TiN 또는 TiCN으로 이루어진 중간층(16); 상기 중간층(15) 위에 코팅되는 TiAlN/CrN 제1나노다층(16); 및 상기 TiAlN/CrN 제1나노다층(16) 위에 최상층으로서 코팅되는 TiAlCN/CrCN 제2나노다층(17); 을 포함하는 코팅층을 가지는 것을 특징으로 하는 엔진용 밸브가 공지되어 있다.In addition, the Korean Patent Publication No. 10-2013-0099763 (published on September 6, 2013) is coated on the surface of the stem portion 11 as the bottom layer and a buffer layer 14 made of Ti or Cr; An intermediate layer 16 coated on the buffer layer 14 and made of CrN or TiN or TiCN; A TiAlN/CrN first nano layer 16 coated on the intermediate layer 15; And a TiAlCN/CrCN second nanolayer 17 coated as the top layer on the TiAlN/CrN first nanolayer 16; Valves for engines are known, which have a coating layer comprising a.
그러나, 상기 종래 특허들은 700℃ 이하에서 운행되는 엔진에 적용되는 것으로 표면을 질화처리하여 표면층의 내마모성, 내식성, 내피로도를 상승시킬 목적으로 표면을 질화처리하고 있고, 크롬도금과 함께 질화처리 하고 있으나, 이러한 질화 층은 고온(750 ℃ 이상) 및 보다 긴 내구성능을 필요로 하는 고출력 및 고온용 엔진에는 적합하지 않다.However, the conventional patents are applied to engines operating at 700° C. or lower, and the surface is nitrided for the purpose of increasing the wear resistance, corrosion resistance, and fatigue resistance of the surface layer by nitriding the surface. , This nitride layer is not suitable for high power and high temperature engines requiring high temperature (over 750°C) and longer durability.
즉, 엔진용 밸브의 축부 표면질화층이 고온에서 노출될 경우 질화확산에 따른 모재의 기공발생에 의하여 밸브축부가 부러지는 등의 심각한 문제점이 발생되므로 이러한 문제점을 해결하기 위하여 고온으로 상승되는 부위의 모제를 더 굵게 하는 설계변경 등의 다양한 시도가 이루어 지고 있으나, 엔진용 밸브의 스템부 표면질화층이 고온에서 노출될 경우 질화층이 경화됨에 따른 부러짐 현상은 본질적으로 방지할 수 없는 문제점이 있었다.That is, when the surface nitriding layer of the shaft portion of the engine valve is exposed at a high temperature, serious problems such as broken valve shaft portions are generated due to the generation of pores due to nitridation diffusion. Various attempts have been made, such as design changes to make the base material thicker, but when the surface nitriding layer of the stem portion of the engine valve is exposed at a high temperature, a cracking phenomenon due to the hardening of the nitriding layer is essentially preventable.
본 발명은 상기 종래 문제점을 해결하기 위하여 고출력 및 고온 엔진용 밸브의 스템부 표면질화층이 고온에서 질화확산에 따른 경화 및 모재의 기공발생에 의하여 밸브의 헤더부 및 스템부 사이부분에 크랙이 발생하고 부러지는 등 내구성능 저하를 방지하기 위하여 밸브의 헤더부 및 스템부 사이의 고온에 노출되는 구간의 표면질화층을 제거하여 내구성능을 향상시킨 고출력 및 고온 엔진용 밸브의 스템부 표면질화 구조 및 표면질화 처리방법을 제공하는 것을 기술적 과제로 한다.In the present invention, in order to solve the above-mentioned problems, the surface nitriding layer of the stem portion of the valve for high power and high temperature engines is cracked in the header portion and the stem portion of the valve by curing and curing of the base material due to nitridation diffusion at high temperature. In order to prevent deterioration of durability, such as breakage, the surface nitridation structure of the high power and high temperature engine valve, which improves durability by removing the surface nitridation layer in the section exposed to high temperature between the header and stem parts of the valve, and It is a technical problem to provide a surface nitriding treatment method.
본 발명은 상기 과제를 해결하기 위하여, 엔진용 밸브 스템부에 표면질화층이 형성된 고출력 및 고온 엔진용 밸브에 있어서, 상기 표면질화층은 상기 스템부중 750℃이상 고온에 노출되는 밸브의 헤더부 및 스템부 사이부분에는 제거된 것을 특징으로 하는 고출력 및 고온 엔진용 밸브의 스템부 표면질화 구조를 기술적 해결방법으로 한다.In order to solve the above problems, in the valve for a high power and high temperature engine having a surface nitriding layer formed on an engine valve stem portion, the surface nitriding layer is a header portion of a valve exposed to high temperatures of 750° C. or higher among the stem portions, and The surface nitriding structure of the stem portion of the valve for high power and high temperature engines, which is removed between the stem portions, is a technical solution.
상기 표면질화층이 제거된 헤더부 및 스템부 사이부분은 헤더부 끝단으로 부터 스템부 방향으로 11~25mm 이격된 간격부분인 것을 기술적 해결방법으로 한다.As a technical solution, the portion between the header portion and the stem portion from which the surface nitride layer has been removed is an interval of 11 to 25 mm spaced from the end of the header portion toward the stem portion.
또한, 본 발명은 고출력 및 고온 엔진용 밸브의 스템부 표면질화 처리방법에 있어서, 상기 엔진용 밸브 스템부에 표면질화층을 형성하는 단계; 및 상기 스템부중 750℃이상 고온에 노출되는 밸브의 헤더부 및 스템부 사이부분의 표면질화층을 제거하는 단계;를 포함하여 구성되는 고출력 및 고온 엔진용 밸브의 스템부 표면질화 처리방법을 기술적 해결방법으로 한다.In addition, the present invention provides a method for treating a surface of a stem portion of a high power and high temperature engine valve, comprising: forming a surface nitride layer on the valve stem of the engine; And removing the surface nitridation layer between the header portion and the stem portion of the valve exposed to high temperatures of 750°C or higher among the stem portions; technically solving the method of treating the surface portion of the stem portion of the valve for high power and high temperature engines, including Do it in a way.
상기 밸브의 헤더부 및 스템부 사이부분의 표면질화층을 제거하는 단계에서 상기 표면질화층을 제거하는 밸브의 헤더부 및 스템부 사이부분은 헤더부 끝단으로 부터 스템부 방향으로 11~25mm 이격된 간격부분인 것을 기술적 해결방법으로 한다.In the step of removing the surface nitridation layer between the header portion and the stem portion of the valve, the portion between the header portion and the stem portion of the valve removing the surface nitridation layer is spaced 11 to 25 mm apart from the end of the header portion toward the stem portion. The gap part is considered as a technical solution.
상기 표면질화층을 제거하는 단계에서 표면질화층의 제거는 연마에 의해 제거되는 것을 기술적 해결방법으로 한다.In the step of removing the surface nitride layer, the removal of the surface nitride layer is a technical solution to be removed by polishing.
본 발명의 고출력 및 고온 엔진용 밸브의 스템부 표면질화 구조 및 표면질화 처리방법은 고출력 및 고온 엔진용 밸브의 헤더부 및 스템부 사이의 고온에 노출되는 구간의 표면질화층을 제거함으로써, 밸브의 헤더부 및 스템부 사이 표면질화층이 고온에서 질화확산에 따른 경화 및 모재의 기공발생에 의하여 밸브의 헤더부 및 스템부 사이부분에 크랙이 발생하고, 부러지는 등 내구성능 저하를 근본적으로 방지할 수 있는 우수한 효과가 있으며, 고출력 및 고온 엔진용 밸브에 있어서 자동차 강국인 일본 보다 기술우위를 점할 수 있는 획기적인 효과가 있다.The surface nitridation structure and surface nitridation treatment method of the high power and high temperature engine valve of the present invention remove the surface nitridation layer of the section exposed to high temperature between the header and stem parts of the high power and high temperature engine valve, thereby The surface nitridation layer between the header part and the stem part prevents degradation of durability, such as cracking and cracking between the header part and the stem part of the valve due to hardening due to nitridation diffusion at high temperature and generation of pores in the base material. It has an excellent effect, and has a breakthrough effect that can occupy a technological advantage over Japan, which is an automobile powerhouse, for high-power and high-temperature engine valves.
도 1은 밸브의 헤더부 및 스템부 사이부분 온도분포 비교도1 is a comparison of the temperature distribution between the header portion and the stem portion of the valve
도 2는 질화확산에 따른 모재의 기공발생 시간결과 비교도 Figure 2 is a comparison of the results of the pore generation time of the base material according to the diffusion of nitride
도 3은 표면질화층 제거 전 후의 고온피로수명 테스트 결과 비교도Figure 3 is a comparison of the results of high temperature fatigue life test before and after removing the surface nitride layer
본 발명은, 엔진용 밸브 스템부에 표면질화층이 형성된 고출력 및 고온 엔진용 밸브에 있어서, 상기 표면질화층은 상기 스템부중 750℃이상 고온에 노출되는 밸브의 헤더부 및 스템부 사이부분에는 제거된 것을 특징으로 하는 고출력 및 고온 엔진용 밸브의 스템부 표면질화 구조를 기술구성의 특징으로 한다.The present invention, in the high-power and high-temperature engine valve having a surface nitride layer formed on the valve stem portion for the engine, the surface nitride layer is removed between the header portion and the stem portion of the valve exposed to high temperatures of 750 ℃ or more of the stem portion The surface nitriding structure of the stem portion of the valve for high-power and high-temperature engines, which is characterized in that it is characterized by the technical composition.
상기 표면질화층이 제거된 헤더부 및 스템부 사이부분은 헤더부 끝단으로 부터 스템부 방향으로 11~25mm 이격된 간격부분인 것을 기술구성의 특징으로 한다.The portion between the header portion and the stem portion from which the surface nitride layer has been removed is characterized by a technical configuration that is a gap portion spaced 11 to 25 mm from the end of the header portion toward the stem portion.
또한, 본 발명은 고출력 및 고온 엔진용 밸브의 스템부 표면질화 처리방법에 있어서, 상기 엔진용 밸브 스템부에 표면질화층을 형성하는 단계; 및 상기 스템부중 750℃이상 고온에 노출되는 밸브의 헤더부 및 스템부 사이부분의 표면질화층을 제거하는 단계;를 포함하여 구성되는 고출력 및 고온 엔진용 밸브의 스템부 표면질화 처리방법을 기술구성의 특징으로 한다.In addition, the present invention provides a method for treating a surface of a stem portion of a high power and high temperature engine valve, comprising: forming a surface nitride layer on the valve stem of the engine; And removing the surface nitridation layer between the header portion and the stem portion of the valve exposed to high temperatures of 750°C or higher among the stem portions; the technical configuration of the method for treating the surface portion of the stem portion of the valve for high power and high temperature engines comprising It is characterized by.
상기 밸브의 헤더부 및 스템부 사이부분의 표면질화층을 제거하는 단계에서 상기 표면질화층을 제거하는 밸브의 헤더부 및 스템부 사이부분은 헤더부 끝단으로 부터 스템부 방향으로 11~25mm 이격된 간격부분인 것을 기술구성의 특징으로 한다.In the step of removing the surface nitridation layer between the header portion and the stem portion of the valve, the portion between the header portion and the stem portion of the valve removing the surface nitridation layer is spaced 11 to 25 mm apart from the end of the header portion toward the stem portion. The gap is characterized by the technical composition.
상기 표면질화층을 제거하는 단계에서 표면질화층의 제거는 연마에 의해 제거되는 것을 기술구성의 특징으로 한다.In the step of removing the surface nitride layer, the removal of the surface nitride layer is characterized by a technical configuration that is removed by polishing.
이하에서는 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자가 용이하게 실시할 수 있도록 본 발명의 실시예 및 도면을 통하여 상세히 설명한다. 그러나 본 발명은 여러 가지 상이한 형태로 구현될 수 있으며, 여기에서 설명하는 실시예 및 도면에 한정되지 않는다.Hereinafter will be described in detail through embodiments and drawings of the present invention so that those skilled in the art to which the present invention pertains can easily practice. However, the present invention may be implemented in various different forms, and is not limited to the embodiments and drawings described herein.
우선, 본 발명의 고출력 및 고온 엔진용 밸브의 스템부 표면질화 구조는 엔진용 밸브 스템부에 표면질화층이 형성된 고출력 및 고온 엔진용 밸브에 있어서, 상기 표면질화층은 상기 스템부중 750℃이상 고온에 노출되는 밸브의 헤더부 및 스템부 사이부분에는 제거되어 구성된다.First, the surface nitriding structure of the stem portion of the high power and high temperature engine valve of the present invention is a high power and high temperature engine valve having a surface nitridation layer formed on the valve stem portion of the engine, wherein the surface nitridation layer is at least 750°C high in the stem portion It is configured to be removed between the header portion and the stem portion of the valve exposed to.
[도 1]을 참조하여 설명하면, 약700℃ 미만으로 운전되는 저출력(MPI)엔진과 고출력 및 고온으로 운전되는 고출력(T-GDI)엔진에서 연소실에 노출되는 밸브 스템부의 온도분포는 저출력(MPI)은 헤더부 끝단으로 부터 스템부 방향으로 11~23mm 이격된 간격부분은 최고온도가 600~700℃ 정도로 운전되므로 밸브 스템부의 표면질화층에 기포조직이 발생하지 않으므로 부러짐현상은 발생하지 않는다.Referring to FIG. 1, the temperature distribution of the valve stem portion exposed to the combustion chamber in the low power (MPI) engine operated at less than about 700° C. and the high power (T-GDI) engine operated at high power and high temperature is low power (MPI). ) Is a gap between 11 and 23 mm away from the end of the header in the direction of the stem, so the maximum temperature is about 600 to 700°C, so there is no bubble structure in the surface nitridation layer of the valve stem, so no breakage occurs.
그러나, 고출력(T-GDI)엔진의 경우, 헤더부 끝단으로 부터 스템부 방향으로 11~25mm 이격된 간격부분은 최고온도가 750℃ 이상으로 운전되므로 밸브 스템부의 표면질화층에 기포조직이 발생되어 부러짐현상이 발생된다.However, in the case of a high-power (T-GDI) engine, since the spaced part spaced 11 to 25 mm from the end of the header portion toward the stem portion is operated at a maximum temperature of 750°C or higher, air bubbles are generated in the surface nitridation layer of the valve stem portion. Breaking occurs.
즉, [도 2]에 나타난 바와 같이, 600~700℃ 정도로 운전되는 저출력(MPI)엔진 밸브 스템부 표면질화층은 질화확산 두께의 변화(A)가 크지 않으므로 질화확산에 따른 모재에 기공이 발생하지 않는 반면, 750℃ 이상으로 운전되는 고출력(T-GDI)엔진 밸브 스템부 표면질화층은 질화확산 두께의 변화(A)가 심하므로 질화확산에 따른 모재에 기공이 심하게 발생된다.That is, as shown in [Fig. 2], since the surface nitridation layer of the low-output (MPI) engine valve stem portion operated at about 600 to 700°C does not have a large change (A) in the diffusion thickness of nitride, pores are generated in the base material according to diffusion of nitride. On the other hand, the surface nitridation layer of the high-power (T-GDI) engine valve stem portion operated at 750°C or higher has a large change (A) in the diffusion thickness of nitride, so that pores are severely generated in the base material according to the diffusion of nitride.
특히, [도 2]를 참조하면, 저출력 700℃(150hrs) 및 고출력 750℃(100hrs)부터 표면에 백색층과 그 아래 흑색층이 형성되며, 질화층이 깊이방향으로 확산되면서 Fe3N 도는 Fe4N의 결합이 깨져 표면층에 기공이 형성되므로 고온노출에 의한 모재의 기공발생을 확인할 수 있다.In particular, referring to FIG. 2, a white layer and a black layer thereon are formed on the surface from low power 700° C. (150 hrs) and high power 750° C. (100 hrs), and the combination of Fe 3 N or Fe 4 N as the nitride layer diffuses in the depth direction. Since the pores are formed in the cracked surface layer, it is possible to confirm the occurrence of pores in the base material due to high temperature exposure.
상기 질화확산에 따른 모재의 기공발생과 관련한 고온피로수명 테스트를 실시한 결과, [도 3]에 도시한 바와 같이, 시험온도 800℃에서 인가응력 160MPa 밸브테스트 한 결과 질화층이 존재하는 경우 에는 3.2 x 105 개폐횟수를 기록한 반면, 질화층이 제거된 경우에는 동일 조건에서 6.3 x 105 개폐횟수를 기록하여 그 내구성능이 훨씬 우수하게 나타났다.As a result of conducting a high temperature fatigue life test related to the generation of pores in the base material according to the diffusion of nitride, as shown in [Fig. 3], a test result of an applied stress 160 MPa valve test at 800° C. results in 3.2 x when a nitride layer is present. 10 5, while recording the number of times opened and closed, when the nitride layer is removed, to record the number of times opening 6.3 x 10 5 in the same conditions was far superior to the durability capability.
이에 따라 상기 표면질화층이 제거된 헤더부 및 스템부 사이부분은 헤더부 끝단으로 부터 스템부 방향으로 11~25mm 이격된 간격부분으로 설계하는 것이 바람직하다.Accordingly, the portion between the header portion and the stem portion from which the surface nitride layer is removed is preferably designed to be spaced apart 11 to 25 mm from the end of the header portion toward the stem portion.
한편, 본 발명의 고출력 및 고온 엔진용 밸브의 스템부 표면질화 처리방법은 상기 엔진용 밸브 스템부에 표면질화층을 형성하는 단계; 및 상기 스템부중 750℃이상 고온에 노출되는 밸브의 헤더부 및 스템부 사이부분의 표면질화층을 제거하는 단계;를 포함하여 구성된다.On the other hand, the method for treating the surface of the stem portion of the high power and high temperature engine valve of the present invention includes forming a surface nitride layer on the valve stem portion for the engine; And removing the surface nitride layer between the stem portion and the stem portion of the valve exposed to high temperatures of 750°C or higher among the stem portions.
이때, 상기 밸브의 헤더부 및 스템부 사이부분의 표면질화층을 제거하는 단계에서 상기 표면질화층을 제거하는 밸브의 헤더부 및 스템부 사이부분은 헤더부 끝단으로 부터 스템부 방향으로 11~25mm 이격된 간격부분으로 설계하는 것이 바람직하다.At this time, in the step of removing the surface nitride layer between the header portion and the stem portion of the valve, the portion between the header portion and the stem portion of the valve for removing the surface nitride layer is 11-25 mm from the end of the header portion toward the stem portion. It is desirable to design with spaced apart parts.
여기서, 상기 표면질화층을 제거하는 단계에서 표면질화층의 제거는 연마에 의해 제거될 수 있음은 물론이다.Here, it is needless to say that the removal of the surface nitride layer in the step of removing the surface nitride layer may be removed by polishing.
이상의 설명은 본 발명의 기술사상을 예시적으로 설명한 것에 불과한 것으로서, 본 발명이 속하는 기술 분야에서 통상의 지식을 가진 자라면 본 발명의 본질적인 특성에서 벗어나지 않는 범위에서 다양한 수정 및 변형이 가능할 것이다. 따라서, 본 발명에 개시된 실시예 및 도면들은 본 발명의 기술 사상을 한정하기 위한 것이 아니라 설명하기 위한 것이고, 이러한 실시예 및 도면에 의하여 본 발명의 기술 사상의 범위가 한정되는 것은 아니다. 본 발명의 보호 범위는 아래의 청구범위에 의하여 해석되어야 하며, 그와 동등한 범위 내에 있는 모든 기술 사상은 본 발명의 권리범위에 포함되는 것으로 해석되어야 할 것이다.The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the embodiments and drawings disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain the scope, and the scope of the technical spirit of the present invention is not limited by the embodiments and the drawings. The scope of protection of the present invention should be interpreted by the claims below, and all technical spirits within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.
본 발명의 고출력 및 고온 엔진용 밸브의 스템부 표면질화 구조 및 표면질화 처리방법은 고출력 및 고온 엔진용 밸브의 헤더부 및 스템부 사이의 고온에 노출되는 구간의 표면질화층을 제거함으로써, 밸브의 헤더부 및 스템부 사이 표면질화층이 고온에서 질화확산에 따른 경화 및 모재의 기공발생에 의하여 밸브의 헤더부 및 스템부 사이부분에 크랙이 발생하고, 부러지는 등 내구성능 저하를 근본적으로 방지할 수 있는 우수한 효과가 있으며, 고출력 및 고온 엔진용 밸브에 있어서 자동차 강국인 일본 보다 기술우위를 점할 수 있는 획기적인 효과가 있으므로 산업상 이용가능성이 있다.The surface nitridation structure and surface nitridation treatment method of the high power and high temperature engine valve of the present invention remove the surface nitridation layer of the section exposed to high temperature between the header and stem parts of the high power and high temperature engine valve, thereby The surface nitridation layer between the header part and the stem part prevents degradation of durability, such as cracking and cracking between the header part and the stem part of the valve due to hardening due to nitridation diffusion at high temperature and generation of pores in the base material. There is an excellent effect, and there is an industrial applicability in the valve for high-power and high-temperature engines, since it has a breakthrough effect that can occupy a technological advantage over Japan, which is an automobile powerhouse.

Claims (5)

  1. 엔진용 밸브 스템부에 표면질화층이 형성된 고출력 및 고온 엔진용 밸브에 있어서, 상기 표면질화층은 상기 스템부중 750℃이상 고온에 노출되는 밸브의 헤더부 및 스템부 사이부분에는 제거된 것을 특징으로 하는 고출력 및 고온 엔진용 밸브의 스템부 표면질화 구조In the valve for a high-power and high-temperature engine having a surface nitridation layer formed on a valve stem portion for an engine, the surface nitridation layer is removed between a header portion and a stem portion of a valve exposed to high temperatures of 750° C. or higher among the stem portions. High-power and high-temperature engine valve surface nitriding structure
  2. 제1항에 있어서,According to claim 1,
    상기 표면질화층이 제거된 헤더부 및 스템부 사이부분은 헤더부 끝단으로 부터 스템부 방향으로 11~25mm 이격된 간격부분인 것을 특징으로 하는 고출력 및 고온 엔진용 밸브의 스템부 표면질화 구조The portion between the header portion and the stem portion from which the surface nitriding layer is removed is a gap portion spaced apart from the end of the header portion in the direction of the stem portion by 11 to 25 mm.
  3. 고출력 및 고온 엔진용 밸브의 스템부 표면질화 처리방법에 있어서, 상기 엔진용 밸브 스템부에 표면질화층을 형성하는 단계; 및 상기 스템부중 750℃이상 고온에 노출되는 밸브의 헤더부 및 스템부 사이부분의 표면질화층을 제거하는 단계;를 포함하여 구성되는 것을 특징으로 하는 고출력 및 고온 엔진용 밸브의 스템부 표면질화 처리방법What is claimed is: 1. A method of surface nitriding of a valve for a high power and high temperature engine, comprising: forming a surface nitriding layer on the valve stem for the engine; And removing the surface nitridation layer between the header portion and the stem portion of the valve exposed to high temperatures of 750°C or higher among the stem portions; and the stem portion surface nitriding treatment of the valve for a high-power and high-temperature engine, comprising: Way
  4. 제3항에 있어서,According to claim 3,
    상기 밸브의 헤더부 및 스템부 사이부분의 표면질화층을 제거하는 단계에서 상기 표면질화층을 제거하는 밸브의 헤더부 및 스템부 사이부분은 헤더부 끝단으로 부터 스템부 방향으로 11~25mm 이격된 간격부분인 것을 특징으로 하는 고출력 및 고온 엔진용 밸브의 스템부 표면질화 처리방법In the step of removing the surface nitride layer between the header portion and the stem portion of the valve, the portion between the header portion and the stem portion of the valve for removing the surface nitride layer is spaced 11 to 25 mm apart from the header end toward the stem portion. Surface nitriding treatment method of valves for high-power and high-temperature engines, characterized in that they are gaps
  5. 제3항에 있어서,According to claim 3,
    상기 표면질화층을 제거하는 단계에서 표면질화층의 제거는 연마에 의해 제거되는 것을 특징으로 하는 고출력 및 고온 엔진용 밸브의 스템부 표면질화 처리방법In the step of removing the surface nitride layer, the removal of the surface nitride layer is removed by polishing, and the method for treating the surface of the stem portion of the valve for high power and high temperature engines is characterized in that it is removed.
PCT/KR2019/018579 2018-12-31 2019-12-27 Nitrided surface structure of high-power and high-temperature engine valve stem, and surface nitriding method WO2020141810A1 (en)

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