KR101269573B1 - Process for Manufacturing Steel Articles having High Contact Strength, high tensile strength and Excellent Corrosion Resistance - Google Patents

Process for Manufacturing Steel Articles having High Contact Strength, high tensile strength and Excellent Corrosion Resistance Download PDF

Info

Publication number
KR101269573B1
KR101269573B1 KR1020120100702A KR20120100702A KR101269573B1 KR 101269573 B1 KR101269573 B1 KR 101269573B1 KR 1020120100702 A KR1020120100702 A KR 1020120100702A KR 20120100702 A KR20120100702 A KR 20120100702A KR 101269573 B1 KR101269573 B1 KR 101269573B1
Authority
KR
South Korea
Prior art keywords
nitriding
heat treatment
phase
steel parts
strength
Prior art date
Application number
KR1020120100702A
Other languages
Korean (ko)
Other versions
KR20120116895A (en
Inventor
김영희
Original Assignee
동아대학교 산학협력단
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 동아대학교 산학협력단 filed Critical 동아대학교 산학협력단
Priority to KR1020120100702A priority Critical patent/KR101269573B1/en
Publication of KR20120116895A publication Critical patent/KR20120116895A/en
Application granted granted Critical
Publication of KR101269573B1 publication Critical patent/KR101269573B1/en

Links

Classifications

    • 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
    • C23C8/28—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 more than one element being applied in one step
    • C23C8/30—Carbo-nitriding
    • C23C8/32—Carbo-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
    • C23C8/06—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
    • 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
    • C23C8/52—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 more than one element being applied in one step
    • C23C8/54—Carbo-nitriding
    • C23C8/56—Carbo-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
    • C23C8/80—After-treatment

Landscapes

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

Abstract

본 발명은 (a) 철강부품에 대하여 오스테나이트화 질화침탄 열처리를 실시하여 상기 청강부품의 표면층에 질소 및 탄소의 확산층을 형성한 후 급냉처리하는 단계; 및 (b) 상기 (a) 단계를 거친 철강부품에 대하여 질화 또는 질화침탄 열처리를 실시하여 단일 입실론상(ε - 상) 또는 입실론상(ε - 상)과 감마프라임상(γ' - 상)의 혼합상으로 구성된 화합물층을 형성하는 단계를 포함하는 고면압강도, 고강도 및 고내식성 철강부품의 제조방법을 제공하여, 고면압강도, 고강도, 고내마모성 및 고내식성을 동시에 부여하여 철강부품의 내구성을 향상시키기 위한 것이다.
본 발명에 의하면, 환경친화적인 방법으로 고온 강도가 유지되며 고면압강도, 고강도 및 고내식성 철강부품을 제조할 수 있다.The present invention comprises the steps of: (a) performing austenite nitriding-carburizing heat treatment on the steel parts to form a diffusion layer of nitrogen and carbon on the surface layer of the steel parts; And (b) nitriding or nitriding-carburizing heat treatment of the steel parts that have undergone the steps (a) to obtain a single epsilon phase (ε-phase) or epsilon phase (ε-phase) and gamma prime phase (γ'-phase). Providing a method of manufacturing high surface pressure strength, high strength and high corrosion resistance steel parts including the step of forming a compound layer composed of a mixed phase, by providing high surface pressure strength, high strength, high wear resistance and high corrosion resistance at the same time to improve the durability of the steel parts It is to let.
According to the present invention, the high temperature strength is maintained by an environmentally friendly method, and high surface pressure strength, high strength and high corrosion resistance steel parts can be manufactured.

Description

고면압강도, 고강도 및 고내식성 철강부품의 제조방법{Process for Manufacturing Steel Articles having High Contact Strength, high tensile strength and Excellent Corrosion Resistance}Process for Manufacturing Steel Articles having High Contact Strength, high tensile strength and Excellent Corrosion Resistance}

본 발명은 고면압강도, 고강도 및 고내식성 철강부품의 제조방법에 관한 것으로, 보다 상세하게는 오스테나이트화 질화침탄과 질화침탄 열처리, 또는 오스테나이트화 질화침탄과 질화 열처리로 구성되는 복합열처리를 실시함으로써 철강부품에 대해 고면압강도, 고강도, 고내마모성 및 고내식성을 부여할 수 있는 고면압강도, 고강도 및 고내식성 철강부품의 제조방법에 관한 것이다.The present invention relates to a method for manufacturing high surface pressure strength, high strength and high corrosion resistance steel parts, and more particularly, a composite heat treatment consisting of austenitic nitriding and nitriding carburization, or austenitic nitriding and nitriding and nitriding heat treatment. Therefore, the present invention relates to a method for manufacturing high surface pressure strength, high strength and high corrosion resistance steel parts, which can impart high surface pressure strength, high strength, high wear resistance and high corrosion resistance to steel parts.

높은 면압강도, 인장강도와 내식성이 요구되는 부품은 일반적으로 침탄 또는 침탄질화 열처리후 아연도금이나 크롬도금을 실시한다.Parts requiring high surface strength, tensile strength and corrosion resistance are generally galvanized or chrome plated after carburizing or carburizing.

침탄 열처리 공정(Carburizing)은 930℃ 정도의 오스테나이트 영역에서 강의 표면에 탄소를 확산시킨 후 급냉하여 심부는 인성을 갖고 표면층은 탄소가 0.8% 중량비 정도로 고용된 마르텐사이트 조직을 얻는 열화학적 표면열처리 공정으로 탄소의 매체에 따라 액체법, 가스법, 진공법, 이온법 등이 있다. Carburizing is a thermochemical surface heat treatment process in which carbon is diffused on the surface of steel in the austenite region at about 930 ° C., followed by quenching to obtain martensitic structure in which the core is tough and the surface layer is 0.8% by weight of carbon. As the carbon medium, there are a liquid method, a gas method, a vacuum method, and an ion method.

침탄질화 열처리(Carbonitriding)는 침탄 열처리시 최표면에 이상산화층의 형성에 따른 내마모성이나 피로강도의 저하를 보완하기 위하여 침탄 열처리 종료전에 단시간 동안 침탄 분위기중에 소량의 질화성 매체를 첨가하는 공정으로 탄소가 주된 경화원소이며 질소는 부가적인 경화원소로서 질소는 최표면에서만 경화효과가 있다.Carbonitriding is a process in which a small amount of nitriding medium is added to the carburizing atmosphere for a short time before the end of the carburizing heat treatment to compensate for the decrease in wear resistance and fatigue strength caused by the formation of the abnormal oxide layer on the outermost surface. It is the main hardening element and nitrogen is an additional hardening element. Nitrogen has a hardening effect only on the outermost surface.

이러한 침탄 또는 침탄질화 열처리에 의해 철강부품의 표면에 경도가 700Hv 이상의 깊은 경화층을 형성함으로써 높은 내마모성, 면압강도, 인장강도, 내피팅성 및 내피로강도 등 우수한 기계적 특성을 얻을 수는 있으나, 이러한 처리에 의해 내식성을 부여할 수는 없으므로 상기 열처리 후 아연도금이나 크롬도금을 실시하여 내식성을 보완하고 있다. By the carburizing or carburizing nitridation heat treatment, a deep hardened layer having a hardness of 700 Hv or more is formed on the surface of the steel part, thereby obtaining excellent mechanical properties such as high wear resistance, surface pressure strength, tensile strength, fitting resistance, and fatigue resistance. Since the corrosion resistance cannot be imparted by the treatment, zinc plating or chromium plating is performed after the heat treatment to compensate for corrosion resistance.

그런데 이러한 도금시에는 도금공정 중 생성되어 강의 내부로 침투한 수소가 취성파괴를 일으키며, 특히 아연도금은 내마모성이 낮아 부품작동시 도금층의 마모로 조기부식이 발생할 수 있으며, 또한 도금공정 중 6가 크롬과 같은 환경부하 물질을 배출하므로 사용상 규제의 대상이 되고 있다.However, during the plating process, hydrogen generated during the plating process and penetrated into the steel causes brittle fracture. In particular, zinc plating has low abrasion resistance, which may cause premature corrosion due to wear of the plating layer during the operation of parts. Emissions of environmentally hazardous substances such as these are subject to regulatory restrictions.

철강부품에 질화 또는 질화침탄 열처리를 실시하는 경우, 예를 들면 본 발명자가 제시한 대한민국 특허 제0095910호에는 질화성 가스에 산화성 가스를 첨가한 질화-산화성 가스분위기에서 강부품을 열처리하여 표면에 산소가 함유된 ε - 상의 질화물층을 형성함으로써 내마모성과 함께 내식성을 부여하는 기술이 개시되어 있다.When nitriding or nitriding and carburizing heat treatment are performed on steel parts, for example, Korean Patent No. 0095910 proposed by the present inventors discloses oxygen on the surface by heat-treating steel parts in a nitriding-oxidizing gas atmosphere in which oxidizing gas is added to nitriding gas. The technique which provides corrosion resistance with abrasion resistance by forming the nitride layer which contains (epsilon)-containing is disclosed.

그러나 상기 특허는 420∼720℃ 의 저온에서 열처리함으로써 질소의 확산깊이가 깊지 않아 고강도를 얻는데 한계가 있고, 이 문제를 해결하기 위해 질화 열처리를 장시간 실시하면 경화깊이를 어느 정도 깊게 할 수는 있으나 본질적으로 경화깊이는 열처리 온도에 크게 의존하므로 이 역시 한계가 있으며 또한 장시간 열처리에 따른 경제적인 문제도 나타난다.However, the patent has a limitation in obtaining high strength because the diffusion depth of nitrogen is not deep by heat treatment at a low temperature of 420-720 ° C., but the cure depth can be deepened to some extent if nitriding heat treatment is performed for a long time to solve this problem. As the depth of hardening is highly dependent on the heat treatment temperature, this also has a limitation and economic problems due to long time heat treatment also appear.

침탄, 침탄질화 또는 담금질 열처리에서 얻은 마르텐사이트 조직은 경도는 높으나 취성이 있으므로 이를 해소하기 위하여 템퍼링 열처리(뜨임)를 실시하는데, 이 템퍼링 열처리는 경화된 강의 취성을 감소시키거나 인성을 개선하는 것을 목표로 하는 열처리이다. The martensite structure obtained by carburizing, carburizing or quenching heat treatment has a high hardness but is brittle, so tempering heat treatment (tempering) is performed to solve this problem. The tempering heat treatment aims to reduce the brittleness or improve the toughness of the hardened steel. It is a heat treatment to be performed.

그런데 침탄, 침탄질화 또는 담금질 열처리를 실시한 철강부품을 내식성을 부여하기 위하여 550℃∼580℃의 온도범위에서 질화열처리를 실시하면 템퍼링 연화에 따라 질소확산층의 경도가 너무 낮아져 고강도를 구현할 수 없다.However, when the nitriding heat treatment is performed at a temperature range of 550 ° C. to 580 ° C. in order to give corrosion resistance to the carburized, carburized or quenched heat treated steel parts, the hardness of the nitrogen diffusion layer becomes too low due to tempering softening, and thus high strength cannot be achieved.

노말라이징(Normalizing) 열처리나 어닐링(Annealing) 열처리된 부품에 대해 질화열처리를 실시하면 템퍼링 연화의 문제는 없으나, 확산층의 경도를 높이는 데는 한계가 있으며 SKD 61 또는 SKD 11 과 같은 금형용 강에 대해 질화 열처리를 실시하면 템퍼링 연화의 문제없이 고강도의 강을 얻을 수 있으나 재료비 및 가공비가 높다는 문제가 있다.Nitriding heat treatment of normalized or annealing heat treated parts does not cause tempering softening, but there is a limit to increasing the hardness of the diffusion layer, and nitriding heat treatment of mold steel such as SKD 61 or SKD 11 When the high strength steel can be obtained without the problem of tempering softening, there is a problem that the material cost and processing cost are high.

본 발명은 이러한 종래기술의 문제점을 감안하여 제안된 것으로, 본 발명의 목적은 일정 수준이상의 심부경도와 함께 고경도 및 고내식성을 부여함으로써 면압강도, 인장강도, 내마모성, 내피팅성 및 내식성이 우수한 철강부품의 제조공정을 제공하는 데 있다.The present invention has been proposed in view of the problems of the prior art, and an object of the present invention is to provide high hardness and high corrosion resistance with a certain level of core hardness, thereby providing excellent surface pressure strength, tensile strength, wear resistance, fitting resistance and corrosion resistance. To provide a manufacturing process for steel parts.

본 발명의 다른 목적 및 장점들은 아래에서 설명될 것이며, 본 발명의 실시예에 의해 알게 될 것이다.Other objects and advantages of the invention will be described below and will be appreciated by the embodiments of the invention.

이와 같은 목적을 달성하기 위하여, 본 발명에 의하면, (a) 철강부품에 대하여 오스테나이트화 질화침탄 열처리를 실시하여 상기 철강부품의 표면층에 질소 및 탄소의 확산층을 형성한 후 급냉처리하는 단계; 및 (b) 상기 (a) 단계를 거친 철강부품에 대하여 질화 또는 질화침탄 열처리를 실시하여 단일 입실론상(ε - 상) 또는 입실론상(ε - 상)과 감마프라임상(γ' - 상)의 혼합상으로 구성된 화합물층을 형성하는 단계를 포함하는 고면압강도, 고강도 및 고내식성 철강부품의 제조방법이 제공된다.In order to achieve the above object, according to the present invention, the step of (a) performing austenitride nitride carburization heat treatment for the steel parts to form a diffusion layer of nitrogen and carbon on the surface layer of the steel parts and then quenched; And (b) nitriding or nitriding-carburizing heat treatment of the steel parts that have undergone the steps (a) to obtain a single epsilon phase (ε-phase) or epsilon phase (ε-phase) and gamma prime phase (γ'-phase). Provided are a method for producing a high surface pressure strength, high strength, and high corrosion resistance steel component including forming a compound layer composed of a mixed phase.

상기 오스테나이트화 질화침탄 공정은 Fe-N계의 A1 변태점(공석온도)인 590℃ 이상의 오스테나이트 영역의 온도에서 질화성 분위기에 침탄성 매체를 소량 첨가한 혼합 분위기를 사용하여 강 표면에 질소와 탄소를 침투 및 확산시킴으로써 후속하는 급냉처리를 통하여 강표면에 질소와 탄소가 고용된 마르텐사이트 조직을 형성하여 높은 내마모성과 피로특성을 확보할 수 있는 열처리 공정이다.The austenitic nitriding carburizing process uses nitrogen in the steel surface by using a mixed atmosphere in which a small amount of carburizing medium is added to the nitriding atmosphere at a temperature of an austenite region of 590 ° C. or higher, which is a Fe 1 N transition point (vacuum temperature). It is a heat treatment process to secure high wear resistance and fatigue characteristics by forming martensitic structure in which nitrogen and carbon are dissolved on the steel surface through subsequent quenching process by infiltrating and diffusing with and carbon.

상기 질화침탄 열처리는 Fe-N계의 A1 변태점(공석온도)인 590℃ 이하의 페라이트 영역의 온도에서 질화성 분위기에 침탄성 매체를 소량 첨가한 혼합 분위기를 사용하여 강 표면에 질소와 탄소를 동시에 침투시키는 열처리 공정이며, 상기 질화 열처리는 순수 질화성 분위기에서 강 표면에 질소만을 침투시키는 열처리 공정이다.The nitriding-carburizing heat treatment uses nitrogen and carbon on the surface of the steel by using a mixed atmosphere in which a small amount of carburizing medium is added to the nitriding atmosphere at a temperature of a ferrite region of 590 ° C. or less, which is a Fe 1 N transition point (vaccanization temperature). At the same time, it is a heat treatment process for permeation, and the nitriding heat treatment is a heat treatment process that only penetrates nitrogen to the steel surface in a pure nitriding atmosphere.

상기 오스테나이트화 질화침탄, 질화침탄 및 질화열처리의 공정에서는 사용되는 질소 및 탄소의 매체에 따라 액체법, 가스법, 진공법 및 이온법 등이 있으며, 각 매체에 따른 구체적인 열처리 공정은 이미 잘 알려져 있으므로 여기서는 상세한 설명을 생략한다.In the processes of austenitic nitriding, nitriding, nitriding and nitriding heat treatment, there are liquid, gas, vacuum, and ion methods depending on the medium of nitrogen and carbon used, and specific heat treatment processes for each medium are well known. Therefore, detailed description is omitted here.

상기한 바와 같이 이루어진 본 발명의 고면압강도, 고강도 및 고내식성 철강부품의 제조공정은 다음과 같은 효과를 제공한다.The manufacturing process of the high surface pressure strength, high strength and high corrosion resistance steel parts of the present invention made as described above provides the following effects.

첫째, 철강부품에 고내마모, 고강도, 고내피팅성 및 고내식성을 부여하여 내구성이 우수한 철강부품을 친환경적인 방법으로 제조할 수 있다.First, it is possible to manufacture steel parts with excellent durability by giving high wear resistance, high strength, high fitting resistance and high corrosion resistance to steel parts in an environmentally friendly way.

둘째, 열처리후 별도의 후가공 공정이 필요하지 않으므로 제조공정이 단순하고 경제적이다.Second, since no additional post-processing process is required after heat treatment, the manufacturing process is simple and economical.

먼저, 본 발명에 따르면 철강부품에 대해 오스테나이트화 질화침탄 열처리를 실시한 후 급냉한다.First, according to the present invention, the austenitic nitride carburization heat treatment is performed on the steel parts, followed by quenching.

본 발명에서 철강부품이라 함은 탄소강 및 합금강을 포함하는 모든 철강소재 또는 이들 철강소재로 제조된 제품을 포함하는 것을 의미한다.In the present invention, the steel part means all steel materials including carbon steel and alloy steel or products made of these steel materials.

오스테나이트화 질화침탄 열처리는 Fe-N계의 A1 변태점(공석온도)인 590℃ 이상, 바람직하게는 Fe-N 계 또는 Fe-C 계에서 750℃∼1100℃ 온도범위의 오스테나이트 영역, 또는 페라이트와 오스테나이트의 혼합영역의 온도범위에서 질화성 분위기에 침탄성 매체를 소량 첨가한 혼합 분위기에서 질소와 탄소를 침투 및 확산시키는 공정으로, 590℃ 이하의 페라이트 영역에서 실시하는 일반적인 질화 열처리에 비해 질소와 탄소의 확산속도가 커서 경화깊이를 크게 확보하는 것이 가능하다.The austenitic nitriding carburization heat treatment is an austenite region having a temperature range of 750 ° C to 1100 ° C in a Fe-N-based A 1 transformation point (vaccanization temperature) of 590 ° C or higher, preferably Fe-N-based or Fe-C-based, or A process that infiltrates and diffuses nitrogen and carbon in a mixed atmosphere in which a small amount of carburizing medium is added to the nitriding atmosphere in the temperature range of the mixed region of ferrite and austenite, compared to the general nitriding heat treatment performed in the ferrite region of 590 ° C. or less. It is possible to secure a large depth of cure because of the high diffusion rate of nitrogen and carbon.

오스테나이트화 질화침탄에서 사용되는 혼합분위기는 질소와 탄소의 매체에 따라 액체법, 가스법, 진공법 및 이온법 등이 있다. 예를 들면, 가스법에서는 암모니아, 탄화수소 및 질소의 분위기에서, 진공법은 암모니아 및 아세틸렌의 분위기에서, 이온법은 질소 및 수소의 분위기에서 각각 실시할 수 있는데, 그 구체적인 공정은 종래의 공정으로 하거나 본 발명자가 제시한 대한민국 특허출원 제10-2009-0034314호에 개시된 방법으로 하여도 좋다.Mixing atmospheres used in austenitic nitriding and carburizing include liquid, gas, vacuum and ion methods depending on the medium of nitrogen and carbon. For example, the gas method can be carried out in an atmosphere of ammonia, hydrocarbons and nitrogen, the vacuum method in an atmosphere of ammonia and acetylene, and the ionic method in an atmosphere of nitrogen and hydrogen, respectively. The method disclosed in Korean Patent Application No. 10-2009-0034314 proposed by the present inventors may be used.

본 발명의 오스테나이트화 질화침탄 공정에 따르면, 철강 부품을 오스테나이트 영역 또는 페라이트와 오스테나이트의 혼합영역까지 가열하여 고온에서 질소와 탄소원자의 높은 확산계수에 의해 주된 경화원소인 질소와 부가적인 경화원소인 탄소원자를 철강부품의 표면으로 충분히 확산시키는 것이 가능하다. According to the austenitic nitriding and carburizing process of the present invention, a steel component is heated to an austenite region or a mixed region of ferrite and austenite, whereby nitrogen and additional hardening elements, which are the main hardening elements, are caused by high diffusion coefficients of nitrogen and carbon atoms at high temperature. It is possible to sufficiently diffuse phosphorus carbon atoms into the surface of steel parts.

이후에 이 철강부품을 상온으로 급냉함으로서 표면은 질소와 탄소의 고용강화 효과와 마르텐사이트 변태에 의하여, 그리고 심부는 마르텐사이트 변태에 의해, 각각 높은 내마모성과 높은 템퍼링 연화저항성 및 고강도 특성을 갖는 철강부품을 얻을 수 있다.Later, the steel parts were quenched to room temperature, the surface of which was caused by the solid-solution strengthening effect of nitrogen and carbon and martensite transformation, and the core part by martensite transformation, respectively, which had high wear resistance, high tempering softening resistance and high strength characteristics. Can be obtained.

이때 오스테나이트 단상영역에서 뿐만 아니라, 페라이트와 오스테나이트의 혼합상 영역에서 오스테나이트화 질화침탄을 실시하여도 질소확산층의 A1 변태점이 590℃로 낮아지므로 오스테나이트 단일상이 되므로 이후의 급냉에 따라 소재의 표면은 소량의 잔류 오스테나이트가 포함된 경도 700Hv 이상의 단일의 마르텐사이트 조직이 되고, 소재의 심부는 가열온도나 강종에 따라 페라이트 및 마르텐사이트의 혼합조직 또는 단일의 마르텐사이트 조직이 나타나므로 요구강도에 따라 가열온도를 적절하게 조절하여 달리할 수 있다. At this time, the A 1 transformation point of the nitrogen diffusion layer is lowered to 590 ° C even in the austenitic single phase region as well as in the mixed phase region of ferrite and austenite. The surface of the material is a single martensite structure with a hardness of 700 Hv or more containing a small amount of retained austenite, and the core part of the material shows a mixed structure of ferrite and martensite or a single martensite structure depending on heating temperature or steel grade. Depending on the strength, the heating temperature can be adjusted appropriately to vary.

이러한 오스테나이트화 질화침탄은 종래의 침탄 또는 침탄질화 열처리에 비해 질소 확산영역의 Ms점이 높으므로 경화능이 좋은 이점이 있다.The austenitic nitride carburizing has a good hardenability since the Ms point of the nitrogen diffusion region is higher than that of the conventional carburizing or carburizing nitriding heat treatment.

한편 오스테나이트화 질화침탄시에는 이후 원활한 질화 또는 질화침탄 열처리에 방해가 되며 박리의 우려가 있는 화합물층이 형성되는 것을 방지하고, 또한 잔류 오스테나이트의 양을 제어하기 위하여 강 내에 침투되는 질소 및 탄소의 양은 합쳐서 0.8∼1.2 중량% 가 되도록 온도 및 분위기를 제어하는 것이 좋다.On the other hand, when austenitizing nitriding is carburized, nitrogen and carbon that penetrate into the steel in order to prevent formation of a compound layer which may interfere with a smooth nitriding or nitriding carburization and possibly cause peeling, and also control the amount of residual austenite It is good to control temperature and atmosphere so that the quantity may be 0.8-1.2 weight% in total.

이 같은 결과를 얻기 위해서는 오스테나이트화 질화침탄 분위기 중의 질소와 탄소 포텐샬의 제어는 실험적, 경험적으로 정할 수 있는데, 기본적으로는 얻어진 강재에 대한 처리결과로부터 피드백해서 분위기를 제어한다. In order to obtain such a result, control of nitrogen and carbon potential in an austenitic nitrocarburizing atmosphere can be determined empirically and empirically. Basically, the atmosphere is controlled by feeding back from the treatment result of the obtained steel.

예를 들면, 가스법의 경우 로내의 미분해 암모니아의 농도를 측정하거나 또는 분해되어 로내에 잔류하는 수소의 농도를 검출하여, 이들 각각의 잔류농도에 따른 강재의 처리결과로부터 피드백해서 암모니아의 도입방법이나 처리온도를 결정할 수 있다.For example, in the case of the gas method, the concentration of undecomposed ammonia in the furnace is measured or the concentration of hydrogen remaining in the furnace is decomposed and fed back from the steel treatment results according to the respective residual concentrations to introduce ammonia. However, the treatment temperature can be determined.

따라서 분위기 및 처리온도를 각각 소정의 조건으로 결정한 후, 이로부터 결정되는 질소의 침투속도를 전제로 처리시간을 결정하여, 질소와 탄소의 침투량과 침투깊이를 적절히 제어하여 설정할 수 있다. Therefore, after determining the atmosphere and the treatment temperature under predetermined conditions, the treatment time is determined on the premise of the nitrogen penetration rate determined therefrom, and the amount and depth of penetration of nitrogen and carbon can be controlled and set appropriately.

분위기 조건 결정시 강재의 탈탄을 방지하기 위하여 강재의 탄소 함량을 고려하여 분위기 중의 탄소 포텐샬을 결정해야 함은 물론이다.In order to prevent decarburization of the steel in determining the atmospheric conditions, it is of course necessary to determine the carbon potential in the atmosphere in consideration of the carbon content of the steel.

이러한 방법으로 각 조건내의 분위기 및 온도로 처리를 하면 고속으로 질소의 침투확산이 가능하여 강재의 두께에 따라서는 단시간내에 심부까지 경화층을 얻는 것이 가능하다.In this way, if the treatment is carried out in the atmosphere and temperature within each condition, the penetration of nitrogen can be diffused at high speed, and depending on the thickness of the steel, it is possible to obtain a cured layer up to the core within a short time.

본 발명의 오스테나이트화 질화침탄으로, 질소가 침투확산한 확산영역은 A1 변태점이 낮아지고 Ms 점이 높아지므로 담금질 처리가 용이한데 처리조건이나 강종에 따라 공냉도 가능하다.In the austenitic nitrocarburizing of the present invention, the diffusion region in which the nitrogen is infiltrated and diffused has a low A1 transformation point and a high Ms point, so that the quenching treatment is easy, but air-cooling is possible depending on the treatment conditions or the steel type.

한편, 오스테나이트 영역에서 급냉하여 마르텐사이트 조직을 얻는 경우, 내부 응력을 완화하고 인성향상을 위한 템퍼링을 실시하는 것이 일반적이다. On the other hand, in the case of quenching in the austenite region to obtain martensite structure, it is common to relieve internal stress and to temper to improve toughness.

그러나, 오스테나이트화 질화침탄 후 후술하는 질화 또는 질화침탄 열처리를 위한 가열시 템퍼링 효과가 부수적으로 나타나므로 오스테나이트화 질화침탄시 별도의 템퍼링 공정을 반드시 실시할 필요는 없으나, 인성의 개선이 더 필요한 경우는 200℃ 내외에서 템퍼링을 실시하여도 무방하지만 이때 확산층의 경도는 다소 떨어질 수 있기 때문이 이 점을 감안하여야 한다.However, since the tempering effect incidentally occurs during heating for nitriding or nitrification heat treatment, which will be described later after austenitic nitriding and carburizing, it is not necessary to perform a separate tempering process during austenitic nitriding and carburizing, but it is necessary to further improve toughness. In this case, tempering may be performed at around 200 ° C., but this should be taken into account because the hardness of the diffusion layer may be somewhat reduced.

다음으로, 질화 또는 질화침탄 열처리를 실시한다.Next, nitriding or nitriding-carburizing heat treatment is performed.

질화 또는 질화침탄 열처리는 내식성을 향상시킬 목적으로 강종에 따라 단일 입실론상(ε - 상) 또는 입실론상(ε - 상)과 감마프라임상(γ' - 상)의 혼합상으로 구성된 화합물층을 얻기 위해 실시하는 것으로 철강부품의 표면에 질소 단독, 혹은 질소와 탄소를 동시에 침투 및 확산시키는 공정이다. Nitriding or nitriding-carburizing heat treatment is performed to obtain a compound layer composed of a single epsilon phase (ε-phase) or a mixed phase of epsilon phase (ε-phase) and gammaprime phase (γ'-phase) depending on the steel grade for the purpose of improving corrosion resistance. It is a process to infiltrate and diffuse nitrogen alone or nitrogen and carbon simultaneously on the surface of steel parts.

일반적으로 질화 또는 질화침탄 열처리는 가스법의 경우 암모니아, 암모니아와 흡열형 가스, 암모니아와 발열형 가스, 암모니아와 질소등의 혼합가스 분위기에서 실시하는데, 여기에 입실론상(ε - 상) 화합물층의 형성을 촉진하기 위하여 이산화탄소, 일산화탄소, 공기, 수증기 또는 메탄을 선택적으로 첨가할 수 있다.In general, nitriding or nitriding-carburizing heat treatment is carried out in a mixed gas atmosphere such as ammonia, ammonia and endothermic gas, ammonia and exothermic gas, and ammonia and nitrogen in the gas method, where the formation of an epsilon phase (ε-phase) compound layer is performed. Carbon dioxide, carbon monoxide, air, water vapor or methane may optionally be added to promote the reaction.

질화 또는 질화침탄 열처리 온도와 시간은 요구하는 화합물층의 두께에 따라 달리하는데, 예를 들면, 570℃에서는 3시간, 610℃에서는 90분, 660℃에서는 45분 간의 처리에 의해 두께 25㎛의 화합물층을 얻을 수 있다. The nitriding or nitriding heat treatment temperature and time vary depending on the required thickness of the compound layer. For example, a compound layer having a thickness of 25 μm is treated by treatment for 3 hours at 570 ° C., 90 minutes at 610 ° C., and 45 minutes at 660 ° C. You can get it.

일반적으로 질화 또는 질화침탄 열처리시 요구되는 화합물층의 두께는 5∼30㎛ 정도인데 이를 위해 질화 또는 질화침탄 열처리는 400℃∼650℃의 페라이트 영역에서 1시간∼24시간 동안 실시한다. 질화처리 시간이 이 보다 짧으면 화합물층의 두께가 너무 얇고, 반면에 시간이 길면 화합물층이 너무 두꺼워 박리가 잘 일어나기 때문이다.Generally, the thickness of the compound layer required for nitriding or nitriding carburization is about 5 to 30 μm. For this purpose, nitriding or nitriding for nitriding is carried out in a ferrite region of 400 ° C. to 650 ° C. for 1 hour to 24 hours. If the nitriding treatment time is shorter than this, the thickness of the compound layer is too thin. On the other hand, if the time is long, the compound layer is too thick and peeling occurs well.

또한 상기 질화 또는 질화침탄 열처리후 요망하는 특성을 얻기 위한 경화깊이는 사용하는 소재나 열처리 공정에 따라 0.01㎜∼3.0㎜로 하는데 경화깊이가 이보다 얕을 경우 요망하는 고강도의 강을 얻을 수 없으며, 경화깊이가 이보다 깊은 경우 처리공정에 장시간이 소요되어 경제적으로 무의미하며 또한 취성이 발생할 수 있기 때문이다.In addition, the hardening depth for obtaining the desired characteristics after the nitriding or nitriding carburization heat treatment is 0.01mm to 3.0mm depending on the material or heat treatment process used, but when the hardening depth is shallower than this, the desired high strength steel cannot be obtained. If the depth is deeper than this, it takes a long time for the treatment process, and it is economically meaningless and brittleness may occur.

그런데 이러한 통상의 질화 또는 질화침탄 열처리에 의해서 내식성이 우수한 입실론상(ε - 상) 또는 입실론상(ε - 상)과 감마프라임상(γ' - 상)의 혼합상으로 구성된 화합물층을 얻을 수는 있으나, 그 처리온도가 낮기 때문에 경화깊이는 그다지 깊지 않으며 경화층의 경도도 높지 않고, 특히 심부는 잘 경화되지 않으므로 질화 또는 질화침탄 열처리 전에 침탄 열처리, 또는 담금질 및 뜨임 열처리를 실시하여 높은 초기 경도를 미리 확보할 수 있다.However, a compound layer composed of an epsilon phase (ε-phase) or a mixture of epsilon phase (ε-phase) and gammaprime phase (γ '-phase) having excellent corrosion resistance can be obtained by the usual nitriding or nitriding heat treatment. Because the processing temperature is low, the depth of hardening is not very deep and the hardness of hardened layer is not high. Especially, the core is hardly hardened, so carburizing heat treatment or quenching and tempering heat treatment is performed before nitriding or nitriding carburizing heat treatment to give high initial hardness. It can be secured.

한편, 질화 또는 질화침탄 열처리를 실시하기 위해 통상적으로 사용하는 공정온도인 550℃ 이상으로 가열하는 경우 침탄 열처리, 또는 담금질 및 뜨임 열처리에 의해 경화된 철강부품이 탄화물의 조대화 및 전위(dislocation) 밀도의 감소 등으로 경도가 낮아지는데 이것을 '템퍼링 연화'라고 한다.On the other hand, when heated to 550 ℃ or more, which is the process temperature normally used for nitriding or nitriding carburization heat treatment, the steel parts hardened by carburizing heat treatment or quenching and tempering heat treatment are used to make carbide coarsening and dislocation density. Hardness is lowered due to the decrease of, which is called 'tempering softening'.

침탄열처리, 또는 담금질 및 뜨임 열처리를 실시한 철강부품에 대해 상기 질화 또는 질화침탄 열처리를 실시하면 입실론상(ε - 상)(Fe3CN) 의 화합물층의 형성으로 높은 내식성은 얻을 수 있으나, 질화 또는 질화침탄 열처리에 의한 경화효과보다 템퍼링에 의한 연화효과가 훨씬 우세하여 소망하는 경도의 경화층을 얻을 수 없게 된다.When the nitriding or nitriding carburization heat treatment is performed on the steel parts subjected to carburization heat treatment or quenching and tempering heat treatment, high corrosion resistance can be obtained by forming a compound layer of epsilon phase (ε-phase) (Fe 3 CN), but nitriding or nitriding The softening effect by tempering is much more superior than the hardening effect by carburizing heat treatment, and the hardened layer of desired hardness cannot be obtained.

한편, 철강부품에 첨가되는 여러 성분중 질소는 500∼700℃의 온도 범위에서 강중에 존재하는 미량의 Ti, Al, Nb 등과 미세한 질화물을 형성하여 고온 유지에 의한 경도 저하를 억제하는 작용, 즉 템퍼링 연화 저항성을 향상시키는 원소로서 알려져 있다.On the other hand, among the various components added to the steel parts, nitrogen forms a small amount of Ti, Al, Nb and the like in the steel in the temperature range of 500 to 700 ° C. to suppress the decrease in hardness due to high temperature retention, that is, tempering. It is known as an element which improves softening resistance.

오스테나이트화 질화침탄 열처리는 상기에서 설명한 바와 같이, 철강부품의 표면에 탄소와 질소를 침투 확산시키는 공정이므로, 표면의 질소농도가 높다는 점을 이용하여 오스테나이트화 질화침탄 열처리된 철강부품에 대해 질화 또는 질화침탄 열처리를 실시하면 질화 또는 질화침탄 열처리가 실시되는 온도범위에서 이미 존재하고 있는 질소가 강재 중의 Ti, Al, Nb 등과 결합하여 미세한 질화물을 형성함으로서 철강부품의 템퍼링 연화를 최소한으로 억제할 수 있다.As described above, the austenitic nitrocarburizing heat treatment is a process of infiltrating and diffusing carbon and nitrogen on the surface of steel parts, so that the nitriding of austenitic nitrocarburizing heat treatment steel parts is performed using the high nitrogen concentration of the surface. Alternatively, when nitriding by carburizing heat treatment, nitrogen existing in the nitriding or nitriding carburizing heat treatment is combined with Ti, Al, and Nb in steel to form fine nitrides, thereby minimizing tempering softening of steel parts. have.

침탄열처리 후 질화 열처리를 실시한 종래의 경우와 비교하면, 본 발명에 따라 오스테나이트화 질화침탄 후 질화 또는 질화침탄 열처리를 실시했을 때 경도가 더 높게 나타난다. 그 이유는 침탄열처리 후 질화 또는 질화침탄 열처리를 실시하면 질화 또는 질화침탄 열처리에 의한 경화효과보다도 템퍼링에 의한 연화효과가 훨씬 크게 작용하여 경도가 급격히 낮아지는 반면, 본 발명에서와 같이 오스테나이트화 질화침탄을 실시하면 질소의 템퍼링 연화억제효과에 의하여 질화 또는 질화침탄 열처리를 실시하여도 경도의 저하가 크지 않기 때문이다.Compared with the conventional case of nitriding heat treatment after carburizing heat treatment, hardness is higher when nitriding or nitriding carburizing heat treatment is performed after austenitic nitriding carburization according to the present invention. The reason is that when nitriding or nitriding carburization heat treatment is performed after carburizing heat treatment, the softening effect by tempering is much greater than the hardening effect by nitriding or nitriding carburization heat treatment, and the hardness is sharply lowered. When carburizing is carried out, the decrease in hardness is not significant even when nitriding or nitriding carburization is performed by the tempering softening inhibitory effect of nitrogen.

따라서 본 발명에 따르면, 질화 또는 질화침탄 열처리에 의해 입실론상(ε - 상)의 화합물을 형성하여 높은 내식성을 확보하고, 오스테나이트화 질화침탄시 확산된 질소에 의한 템퍼링 연화 억제효과 및 질소의 경화효과로 인하여 표면경도가 우수한 철강부품을 제조할 수 있게 된다. 또한 질소의 템퍼링 연화 억제효과로 고온에서 강도가 급격히 낮아지는 것을 방지할 수 있으므로 고온 강도를 적정 수준으로 유지할 수 있는 장점이 있다.Therefore, according to the present invention, forming a epsilon phase (ε-phase) compound by nitriding or nitriding carburization heat treatment to ensure high corrosion resistance, inhibiting tempering softening effect by nitrogen diffused during austenite nitriding and carburizing, and curing of nitrogen Due to the effect, it is possible to manufacture steel parts with excellent surface hardness. In addition, it is possible to prevent the strength from being sharply lowered at high temperatures due to the tempering softening inhibitory effect of nitrogen, which has the advantage of maintaining the high temperature strength at an appropriate level.

본 발명은 구와 구 또는 구와 면이 접촉하는 헤르츠 접촉과 같이 고면압 강도, 고강도, 내피팅성 및 내식성이 동시에 요구되는 부품의 내구성 향상에 특히 유용한 기술이다.The present invention is a particularly useful technique for improving the durability of components requiring high surface pressure strength, high strength, fitting resistance and corrosion resistance at the same time, such as sphere contact with a sphere or a sphere contacting a sphere with a sphere.

한편, 오스테나이트화 질화침탄 후에 실시하는 질화 또는 질화침탄 열처리 공정은 특별히 한정하지 않으나, 본 발명자의 특허 제0095910호가 제안하는 방법으로 실시하는 경우 높은 내식성과 함께 은백색의 외관을 얻을 수 있으며, 이후 산화처리에 의해 다양하고 미려한 컬러도 부여할 수 있는 잇점이 있다.On the other hand, the nitriding or nitriding heat treatment process carried out after the austenitic nitriding carburization is not particularly limited, but when carried out by the method proposed by the inventor's patent No. 0095910 can obtain a silvery white appearance with high corrosion resistance, and then oxidized There is an advantage that a variety of beautiful colors can be provided by the processing.

또 상기 질화 또는 질화침탄 열처리후 공냉 또는 오일냉각을 하여도 무방하지만 잔류 오스테나이트를 마르텐사이트로 변태시켜 표면경도를 더 높이기 위하여 수냉을 실시할 수도 있다.In addition, air cooling or oil cooling may be performed after the nitriding or nitriding carburization heat treatment, but water cooling may be performed in order to transform the retained austenite into martensite to further increase the surface hardness.

<실시예 1> &Lt; Example 1 >

열간압연 소재를 사용하여 자동차의 유리 승강용 섹터기어(sector gear)를 프레스 성형한 후, 종래 방법에 따라, 침탄열처리 및 전기아연도금(MFZN8C 상당) 을 실시한 결과, 표면경도는 Hv 720, 전경화 깊이는 0.6㎜이었으며, 이를 염수분무시험(KS D 9502)으로 내식성을 평가한 결과, 70시간 이후 백록이 발생하였다.After hot-rolled material was used to press-form a sector gear for automobile glass lifting, carburizing heat treatment and electro-zinc plating (equivalent to MFZN8C) were carried out according to the conventional method, and the surface hardness was Hv 720 and the depth of foreground. Was 0.6㎜, which was evaluated by the salt spray test (KS D 9502).

한편, 상기와 동일 소재로 제작한 섹터기어를 780℃에서 50 부피%의 암모니아, 1부피%의 프로판 및 49 부피%의 질소로 구성된 혼합가스 분위기로 4시간 동안 오스테나이트화 질화침탄을 실시한 후 상온의 물에 급냉하였다. 이 기어를 550℃에서 70부피%의 암모니아, 10부피%의 이산화탄소 및 20부피%의 질소로 구성된 혼합가스 분위기로 3시간 동안 질화침탄을 실시하고 공냉한 결과, 표면경도 Hv 800, 전경화 깊이는 1.1㎜ 이었으며 내식성을 평가한 결과 200시간 이후에도 발청이 없었다.Meanwhile, the sector gear made of the same material as above was subjected to austenitic nitriding for 4 hours in a mixed gas atmosphere composed of 50% by volume of ammonia, 1% by volume of propane, and 49% by volume of nitrogen at room temperature. It was quenched in water. The gears were quenched and air-cooled at 550 ° C for 3 hours in a mixed gas atmosphere consisting of 70% by volume ammonia, 10% by volume carbon dioxide, and 20% by volume nitrogen, resulting in a surface hardness of Hv 800 and a depth of foreground of 1.1. It was ㎜ and corrosion resistance was not found even after 200 hours.

<실시예 2> <Example 2>

판재를 사용하여 자동차 수동변속기용 클러치의 부품인 서브 플레이트(sub plate) 를 성형하고, 종래 방법에 따라, 침탄 열처리 및 산화처리한 결과, 표면경도 Hv 650, 전경화 깊이 0.3㎜이었으며 이 서브 플레이트를 염수분무시험(KS D 9502)으로 내식성을 평가한 결과 60분 이내에 발청이 있었다.Subplates, which are parts of clutches for manual transmissions of automobiles, were formed using plate materials and carburized and oxidized according to the conventional method. The surface hardness was Hv 650 and the depth of foreground was 0.3 mm. Corrosion resistance was evaluated by spray test (KS D 9502).

한편, 상기와 동일한 이 서브 플레이트를 800℃에서 50부피%의 암모니아, 2 부피%의 메탄 및 48 부피%의 질소로 구성된 혼합가스 분위기로 3시간 동안 오스테나이트화 질화침탄을 실시한 후 80℃로 유지되는 오일에 급냉하였다. 이 서브 플레이트를 550℃에서 60부피%의 암모니아, 10부피%의 이산화탄소 및 30 부피%의 소로 구성된 혼합가스 분위기로 3시간 동안 질화침탄을 실시하고 상온의 물에 수냉한결과, 표면경도 Hv 750, 전경화 깊이는 0.9㎜ 이었으며 염수분무시험(KS D 9502)으로 내식성을 평가한 결과, 150시간 이후에도 발청이 없었다.On the other hand, this same sub-plate was maintained at 80 ° C. after performing austenitride nitriding for 3 hours in a mixed gas atmosphere composed of 50% by volume of ammonia, 2% by volume of methane, and 48% by volume of nitrogen at 800 ° C. Was quenched in the oil. The subplate was subjected to nitriding for 3 hours in a mixed gas atmosphere composed of 60% by volume of ammonia, 10% by volume of carbon dioxide, and 30% by volume of cows at 550 ° C., and then cooled in water at room temperature. Foreground depth was 0.9 mm and corrosion resistance was evaluated by salt spray test (KS D 9502).

<실시예 3><Example 3>

SCM 415 소재를 가공한 후 침탄열처리를 실시하여 자동차용 피니언 샤프트를 제조한 결과 이 피니언 샤프트의 표면 경도는 Hv 800, 유효경화깊이는 0.35㎜이었다. After the SCM 415 material was processed, carburizing heat treatment was carried out to produce an automotive pinion shaft. The surface hardness of the pinion shaft was Hv 800 and the effective hardening depth was 0.35 mm.

SCM 415 소재로 동일한 치수의 피니언 샤프트를 가공하였으며 820℃에서 60부피%의 암모니아, 1.5 부피% 의 부탄 및 38.5 부피%의 질소로 구성된 혼합가스 분위기로 5시간 동안 오스테나이트화 질화침탄을 실시하고 상온의 물에 급냉하였다. 그 후 이 피니언 샤프트를 560℃에서 60% 부피의 암모니아, 40% 부피의 질소로 구성된 혼합가스 분위기로 4시간 동안 질화열처리를 실시하여 80℃로 유지되는 오일에 급냉한 결과, 표면경도 Hv 850, 유효경화 깊이는 0.45㎜이었다.A pinion shaft of the same dimensions was machined from SCM 415 and subjected to austenitic nitriding for 5 hours in a mixed gas atmosphere consisting of 60% by volume ammonia, 1.5% by volume butane and 38.5% by volume nitrogen at 820 ° C. It was quenched in water. The pinion shaft was then quenched in an oil maintained at 80 ° C. for 4 hours in a mixed gas atmosphere consisting of 60% volume ammonia and 40% volume nitrogen at 560 ° C., resulting in a surface hardness of Hv 850, The effective hardening depth was 0.45 mm.

이상으로부터 알 수 있는 바와 같이, 본 발명에 의하면, 고내마모, 고내피팅성 및 고내식성을 부여하여 내구성이 우수한 철강부품을 친환경적인 방법으로 제조할 수 있다.As can be seen from the above, according to the present invention, by providing a high wear resistance, high fitting resistance and high corrosion resistance, steel parts excellent in durability can be manufactured in an environmentally friendly method.

이상과 같이, 본 발명은 비록 한정된 실시예에 의해 설명되었으나, 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자에 의해 본 발명의 기술사상과 아래에 기재될 특허청구범위의 균등 범위 내에서 다양한 수정 및 변형이 가능함은 물론이다.As described above, although the present invention has been described by means of a limited embodiment, it will be apparent to those skilled in the art that the present invention may be modified within the equivalent scope of the technical spirit of the present invention and the claims to be described below. Of course, modifications and variations are possible.

Claims (4)

(a) 철강부품에 대하여 590℃ 이상의 온도에서 오스테나이트화 질화침탄 열처리를 실시하여 상기 철강부품의 표면층에 질소 및 탄소의 확산층을 형성한 후 급냉처리하는 단계; 및
(b) 상기 (a) 단계를 거친 철강부품에 대하여 590℃ 이하의 온도에서 질화 또는 질화침탄 열처리를 실시하여 단일의 입실론상(ε - 상) 또는 입실론상(ε - 상)과 감마프라임상(γ' - 상)의 혼합상으로 구성된 화합물층을 형성하는 단계를 포함하며,
상기 (a) 단계에서, 상기 오스테나이트화 질화침탄 열처리는 전체의 처리 시간에 걸쳐 질화성 분위기에 침탄성 매체를 첨가한 혼합 분위기에서 열처리를 실시하여 상기 철강부품의 표면층에 질소 및 탄소의 확산층을 형성하고, 상기 확산층이 형성된 상기 철강부품을 급냉처리하여 상기 철강부품의 표면에 질소와 탄소가 고용된 마르텐사이트 조직을 형성하고,
상기 (b) 단계의 상기 질화 열처리는 질화성 분위기에서 열처리를 실시하며, 상기 질화침탄 열처리는 질화성 분위기에 침탄성 매체를 첨가한 혼합 분위기에서 열처리를 실시하는 것을 특징으로 하는 고면압강도, 고강도 및 고내식성 철강부품의 제조방법.(a) subjecting the steel parts to austenitic nitriding-carburizing heat treatment at a temperature of 590 ° C. or higher to form a diffusion layer of nitrogen and carbon on the surface layer of the steel parts, and then quenching them; And
(b) A single epsilon phase (ε-phase) or epsilon phase (ε-phase) and gammaprime phase (I) were subjected to nitriding or nitriding and carburizing heat treatment at a temperature of 590 ° C. or lower on the steel parts which passed step (a). forming a compound layer consisting of a mixed phase of γ'-phase),
In the step (a), the austenitic nitride carburization heat treatment is carried out in a mixed atmosphere in which a carburizing medium is added to the nitriding atmosphere over the entire treatment time to form a diffusion layer of nitrogen and carbon on the surface layer of the steel part. Forming a martensite structure in which nitrogen and carbon are dissolved on the surface of the steel part by quenching the steel part having the diffusion layer formed thereon;
The nitriding heat treatment of step (b) is carried out in a nitriding atmosphere, and the nitriding carburization heat treatment is performed in a mixed atmosphere in which a carburizing medium is added to the nitriding atmosphere. And a method for producing high corrosion resistant steel parts. 제 1항에 있어서,
상기 (a) 단계의 오스테나이트화 질화침탄 열처리는 Fe-N 또는 Fe-C 계의 오스테나이트 단상 영역 또는 페라이트와 오스테나이트의 혼합상 영역의 온도범위에서 실시하는 것을 특징으로 하는 고면압강도, 고강도 및 고내식성 철강부품의 제조방법.The method of claim 1,
The austenitic nitride carburizing heat treatment of step (a) is performed at a temperature range of an austenitic single-phase region of Fe-N or Fe-C system or a mixed-phase region of ferrite and austenite. And a method for producing high corrosion resistant steel parts. 제 1항에 있어서,
상기 (a) 단계의 급냉처리는 유냉 또는 수냉하는 것을 특징으로 하는 고면압강도, 고강도 및 고내식성 철강부품의 제조방법.The method of claim 1,
The quenching process of step (a) is a method of manufacturing high surface pressure strength, high strength and high corrosion resistance steel parts, characterized in that the oil-cooled or water-cooled. 제 1항에 있어서,
상기 오스테나이트화 질화침탄 열처리에 의해 상기 철강부품 내에 침투되는 질소와 탄소의 양은 0.8∼1.2중량%인 것을 특징으로 하는 고면압강도, 고강도 및 고내식성 철강부품의 제조방법.The method of claim 1,
The method of manufacturing high-strength strength, high-strength and high corrosion-resistant steel parts, characterized in that the amount of nitrogen and carbon permeated into the steel parts by the austenitic nitriding carburization heat treatment is 0.8 to 1.2% by weight.
KR1020120100702A 2012-09-11 2012-09-11 Process for Manufacturing Steel Articles having High Contact Strength, high tensile strength and Excellent Corrosion Resistance KR101269573B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020120100702A KR101269573B1 (en) 2012-09-11 2012-09-11 Process for Manufacturing Steel Articles having High Contact Strength, high tensile strength and Excellent Corrosion Resistance

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020120100702A KR101269573B1 (en) 2012-09-11 2012-09-11 Process for Manufacturing Steel Articles having High Contact Strength, high tensile strength and Excellent Corrosion Resistance

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
KR1020090113001A Division KR20110056607A (en) 2009-11-23 2009-11-23 Process for manufacturing steel articles having high contact strength, high tensile strength and excellent corrosion resistance

Publications (2)

Publication Number Publication Date
KR20120116895A KR20120116895A (en) 2012-10-23
KR101269573B1 true KR101269573B1 (en) 2013-06-05

Family

ID=47285039

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020120100702A KR101269573B1 (en) 2012-09-11 2012-09-11 Process for Manufacturing Steel Articles having High Contact Strength, high tensile strength and Excellent Corrosion Resistance

Country Status (1)

Country Link
KR (1) KR101269573B1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114317898B (en) * 2021-12-24 2024-01-26 哈尔滨工程大学 Method for improving abrasion resistance and corrosion resistance of ferrite stainless steel surface

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10176219A (en) * 1996-12-17 1998-06-30 Komatsu Ltd Steel parts for high bearing resistance, and their production
KR19980066538A (en) * 1997-01-25 1998-10-15 김영희 Heat treatment method of mold steel

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10176219A (en) * 1996-12-17 1998-06-30 Komatsu Ltd Steel parts for high bearing resistance, and their production
KR19980066538A (en) * 1997-01-25 1998-10-15 김영희 Heat treatment method of mold steel

Also Published As

Publication number Publication date
KR20120116895A (en) 2012-10-23

Similar Documents

Publication Publication Date Title
JP5994924B2 (en) Shaped material of induction-hardened parts and method for manufacturing the same
KR101294900B1 (en) Steel for nitrocarburization, nitrocarburized components, and production method for same
US11047036B2 (en) Method of fabricating a nitrided low-alloy steel part
JP6520347B2 (en) Forming material of induction hardened parts, induction hardened parts, and manufacturing method thereof
JP5632454B2 (en) Spring steel and steel surface treatment method
JP4737601B2 (en) High temperature nitriding steel
KR101269573B1 (en) Process for Manufacturing Steel Articles having High Contact Strength, high tensile strength and Excellent Corrosion Resistance
KR101269572B1 (en) Surface heat treatment process for machine parts having high durability and high corrosion resistance
US20220290268A1 (en) Case-hardened steel part for use in aeronautics
KR20110056607A (en) Process for manufacturing steel articles having high contact strength, high tensile strength and excellent corrosion resistance
KR101839166B1 (en) The method of carbonitriding process for boron added steel
JPH0570925A (en) Method for carbonitriding heat treatment of high strength gear small in strain
KR100240042B1 (en) High temperature nitro-carbonizing treatment of metal
KR100988702B1 (en) A quenched nitride and the method of manufacture thereof
KR20000027040A (en) Method for heat treatment of surface of steel to reduce heating transformation
GB2328953A (en) A process for hardening high alloy steels
JP2019049032A (en) Steel material for carburization processing
WO2023162515A1 (en) Method for producing steel member
KR101054775B1 (en) Alloy Steel and Carburizing Heat Treatment Method for Vehicle Transmission Gears
KR100922619B1 (en) Steel having high strength and methode for manufacturing the same
CN116145074A (en) Method for heat treatment of steel product, steel product and bearing ring
KR20100115637A (en) Eco friendly nitrocarburizing process at high temperature
KR20160075220A (en) Nitrogen solution process
KR101327136B1 (en) Transmission gear and manufacturing method thereof
JP2006131922A (en) Method for manufacturing gear made of steel

Legal Events

Date Code Title Description
A107 Divisional application of patent
A201 Request for examination
E902 Notification of reason for refusal
E701 Decision to grant or registration of patent right
GRNT Written decision to grant
FPAY Annual fee payment

Payment date: 20170502

Year of fee payment: 5

FPAY Annual fee payment

Payment date: 20180524

Year of fee payment: 6

FPAY Annual fee payment

Payment date: 20190610

Year of fee payment: 7