玖、發明說明： 【發明所屬之技術領域】 本發明係關於用於車輛或摩托表 播古★、一 〈零件’更特別關於一 種具有改艮高溫軟化特徵之鐵合今 件之方法。 ’令件及製造該鐵合金零 【先前技術】 主要包含Fe(鐵）且含C(碳）的各種 口口— & # J鐵合金鋼習用於機 备令件。機器零件根據其用途需要 奋^ A 、而要具有各種性能，如高硬 又、问&度、高抗疲勞性、高抗腐蝕 叫& 次呵杬磨耗性。機 备令件表面尤其需要具有高硬度。 通常’為改良表面硬度及強度’機器零件要經過渗 理’以溶解其表面中的碳。具有渗硬表面的機器零件之— 般韻自球軸承鋼(SUJ)形成的轴承零件。例如，曰本中 =第账1 1 7438號揭示-種由鐵合金鋼製成且具輪 化表面之滾動袖承。由於其使用所處的條件，滾動幸由承所 :零件必須具有高強度°公開的輛承零件由具有高C(碳）含 K鐵合金鋼製成’並經過參碳處理’以便不僅表面而且 其内邵均具有高強度。 汾鐵合金鋼亦用於車輛和摩托的零件。例如，日本申請案 第跡6G236號揭示_種以輕微犧牲表面硬度製造具有高可 力口工性之高精度零件之方法。更確切而言，使零件之表面 更度降低到木-程度，以用具有低C(碳)含量之表面硬化鋼 及在參碟處理後依表面硬化鋼之化學组成控制冷卻速率將 零件表面之金屬結構轉化成珍珠體結構’從而改良零件之 可力Π工性。 户車摩Γ斤用的零件亦需要具有内部勃度及高表面硬 :^令件施加壓縮負荷，零件的㈣必須具有章刃度， —秸编“荷。例如，曰本申請案第20,31〇329號揭示 製用义内燃機或壓縮機之表面硬化連杆。連杆由低碳鋼 ，，並於渗碳器中加熱，以自其表面渗透c(碳)渗透物。 心：化的表面由多次滲碳處理硬化。連杆具有具高韌度 -人鋼〈内邙及具有咼碳濃度之表面，以便減輕 加的負荷。 也 由本發明解決的問題 斤t 可藉由使用低碳鋼給予零件内部勃度及藉由 f碳處理給予其表面硬度。然而，如果零件具有經常二口 :縮負荷之表面’壓縮負荷不可能單獨由内部勃度減輕。 因此，零件不能經受壓縮負荷，並隨時間變得疲勞化。 除壓縮負荷外，還要對車輛或摩托所料零件施加旋轉 負荷。當零件材料疲勞化時，在其表面產生裂痕，導致表 面的凹痕或片落，這縮短零件的使用壽命。 此=，車輛或摩托中的一些零件在約200。0高溫使用。然 而’零件所用的習知材料顯示在M0(rc硬度降低，且可能 在表面中具有裂痕，這同樣縮短零件的疲勞壽命。 j發明已解決以上問題’因此，本發明之目的為提供具 有高表面硬度且抗疲勞性及高溫抗軟化性極佳之鐵合金零 件及製造該鐵合金零件之方法。 問題解決方法 1224143 為實現以上目的已進行各種研究，而低碳鋼零件的高溫 柷軟化性可由滲碳和碳氮化處理改良，該處理為其中在高 碳濃度滲碳以產生碳化物[如，碳化鐵（F^C)]沈澱作用的第 一滲碳處理和第二碳氮化處理之組合，以形成包含5〇%或 更V保田奥氏體相及3〇〇/。或更少硬化物相且其中氮溶於零 件表面之金屬結構。 【發明内容】 本發明特徵為，自最外表面至其01毫米深度之區域之金 屬結構包括50面積％或更少保留奥氏體相及3〇面積％或更少 碳化物相’ i包含〇.5〇質量％或更少氮，組成碳化物相的碳 化物具有5微米或更小平均顆粒大小以及在自其最外表面至 少0.55*米之深度之硬度為7〇〇hv或更高。 根據本發明，為改良零件的表面硬度和高溫抗軟化性， 在零件表面沈殿具有5微米或更小平均直徑之碳化物，以生 成碳竭目，並在其金屬結構中溶解不大於〇·5〇質量％之 氮’隨後回火，以增強抗軟化性。 疋化物為由Fe或Cr及C等間共價鍵形成的碳化鐵， 其係經沈殿’以改良零件表面硬度。當碳化物的平均直徑 大到超過5 Μ不時’將由對其施加的壓縮負荷產生應力集 中:因此，在本發明中，規定平均直徑為5微米或更小。為 提高表面硬度’碳化物顆粒較佳微細且均勾在零件表面區 域中的金屬結構中分散。碳化物分析如下。用苦醇㈣⑽ 名虫刻樣品表面》以增强雜仆札 人化物和金屬相間之對比，並拍攝 表面SEM像片#然後’用圖像處理裝置自sem像片得到碳 1224143 化物相的面積率。 又月中，規足金屬結構中氮之量為〇 · 5 〇質量〇/。或更 小。此係因4，當氮之量超敎5G質量％時，硬'化性降低， 且保留的奥氏體量急劇增加。 本毛月中，規定保留的奥氏體相之比率為5〇面積％或 2小。保留的奥氏體相如下分析。用c〇k_“昌射作為乾， Χθ射線衍射對α相的（)和（220)面及r相的（220)和⑴i) ::到四個峰比率，並自峰比率平均值得到保留奥氏體相 白0比率。 勺明中’自最外表面至G.1毫米深度之金屬結構較佳 G S : y20 面積 0/0之馬丁體（martensite)相。 ^表面 衣度指疋為〇·1毫米和〇·55毫米，但並不限 於此。此等數字户 _ 曰、·，’ ·1φ米和0·55毫米之深度，且該深度 了增加或降低0.05毫米。 在本發明中，左白 ~ 戶 卜表面至少3·〇毫米或更多深度之硬 反季父佳為5 5 H R Γ1斗、$。 之 ^氐。在自最外表面3毫米或更多深度 -或以後將被稱為“零件的核部分，，。 根據本發明，零件 戽卜 千核4分《韌度保證減輕對零件施加的 土 何’並改良抗疲勞。、 鋼作為零件的材料。—初度，較佳用低碳 在以上本發明中，彿 之鐵合金製成。.·否金零件較佳由具有以下化學組成 鈕也而^ _合金零件較佳由-種鐵合金材料(SCM :鉻_说明. Description of the invention: [Technical field to which the invention belongs] The present invention relates to a method for the use of a vehicle or a motorcycle watch, a <part ', and more particularly, to a method for modifying an iron alloy with high temperature softening characteristics. ‘Order parts and manufacture of this ferroalloy zero [Prior technology] Various mouthpieces mainly containing Fe (iron) and containing C (carbon) — &# J ferroalloy steel is customarily used for machine spare parts. Machine parts need to work hard according to their application, and have various properties, such as high hardness, high resistance, high fatigue resistance, and high corrosion resistance. In particular, the surface of machine parts needs to have high hardness. Generally, "for improving the surface hardness and strength", the machine parts are subjected to infiltration "to dissolve the carbon in the surface. One of the machine parts with hardened surfaces-bearing parts made of ball bearing steel (SUJ). For example, Chinese Version = No. 1 1 7438 discloses a rolling sleeve bearing made of ferroalloy steel with a rounded surface. Due to the conditions in which it is used, rolling is fortunately performed by the carrier: the parts must have high strength. The disclosed car carrier parts are made of steel with high C (carbon) K-containing ferroalloy steel 'and undergo carbon treatment' so that not only the surface but also its Inner Shao has high strength. Fen ferroalloy steel is also used in vehicle and motorcycle parts. For example, Japanese Application No. 6G236 discloses a method for manufacturing high-precision parts with high mouthability at a slight sacrifice of surface hardness. More precisely, the surface of the part is reduced to a wood-degree, in order to use a surface-hardened steel with a low C (carbon) content and control the cooling rate according to the chemical composition of the surface-hardened steel after the dish treatment to control the surface of the part. The metal structure is transformed into a pearl structure to improve the workability of the part. The parts used for household car friction also need to have internal stiffness and high surface hardness: ^ order to apply a compressive load to the part, the part must have a cutting edge degree, — straw braided. For example, the 20th of this application, No. 31〇329 discloses a surface-hardened connecting rod for an internal combustion engine or a compressor. The connecting rod is made of low-carbon steel and heated in a carburizer to penetrate c (carbon) permeate from its surface. Heart: chemical The surface is hardened by multiple carburizing treatments. The connecting rod has a surface with high toughness-steel and inner surface with carbon concentration in order to reduce the load. The problem also solved by the present invention can be achieved by using low carbon Steel gives the internal stiffness of the part and its surface hardness by f-carbon treatment. However, if the part has a regular two-portion: shrinkage of the surface, the compressive load cannot be alleviated by the internal stiffness alone. Therefore, the part cannot withstand the compressive load, It becomes fatigued with time. In addition to the compressive load, a rotating load is also applied to the parts of the vehicle or motorcycle. When the component material is fatigued, cracks are generated on the surface, resulting in surface dents or chipping, which shortens Components Service life. This =, some parts of the vehicle or motorcycle are used at a high temperature of about 200. 0. However, the conventional materials used for the parts are shown at M0 (rc hardness is reduced, and may have cracks in the surface, which also shortens the parts' Fatigue life. The invention has solved the above problem. Therefore, the object of the present invention is to provide a ferroalloy part with high surface hardness, excellent fatigue resistance and high temperature softening resistance, and a method for manufacturing the ferroalloy part. The problem solving method 1224143 is to achieve Various studies have been performed for the above purposes, and the high-temperature softening properties of low-carbon steel parts can be improved by carburizing and carbonitriding treatments, in which carburizing at a high carbon concentration to produce carbides [eg, iron carbide (F ^ C )] A combination of the first carburizing treatment and the second carbonitriding treatment for precipitation to form a phase containing 50% or more of the Houda austenite phase and 300% or less of a hardened phase in which nitrogen is dissolved [Metal structure on the surface of a part] [Summary of the invention] The present invention is characterized in that the metal structure from the outermost surface to a region of its depth of 01 mm includes 50 area% or less retained austenite phase and 30% by area or less of the carbide phase 'i contains 0.50% by mass or less of nitrogen, the carbides constituting the carbide phase have an average particle size of 5 microns or less and at least 0.55 * from its outermost surface * The hardness of the depth of meters is 700hv or higher. According to the present invention, in order to improve the surface hardness and high-temperature softening resistance of the part, the surface of the part has a carbide with an average diameter of 5 microns or less to generate carbon exhaust. And then dissolve no more than 0.50% by mass of nitrogen in its metal structure and subsequently temper it to enhance softening resistance. The halide is iron carbide formed by covalent bonds such as Fe or Cr and C, which The system was approved by Shen Dian to improve the surface hardness of the part. When the average diameter of the carbide is larger than 5 M from time to time, stress concentration will be caused by the compressive load applied to it: Therefore, in the present invention, the average diameter is specified to be 5 microns or more small. To increase the surface hardness, the carbide particles are preferably fine and dispersed in the metal structure in the surface area of the part. The carbide analysis is as follows. The surface of the sample was carved with bitter alcohol to enhance the contrast between the human and metal phases, and the surface SEM image # was taken. Then, the area ratio of the carbon 1224143 chemical phase was obtained from the sem image using an image processing device. In the middle of the month, the amount of nitrogen in the regular metal structure was 0.50 mass. Or smaller. This is due to the fact that when the amount of nitrogen exceeds 5G mass%, the hardenability decreases, and the amount of retained austenite sharply increases. In this wool month, the ratio of retained austenite phase is specified to be 50 area% or less. The retained austenite phase is analyzed as follows. Using cok_ "chang radiation as the stem, Xθ-ray diffraction for the () and (220) planes of the α phase and (220) and ⑴i) of the r phase :: to four peak ratios, and retained from the average of the peak ratio Austenite phase white 0 ratio. Spoon Mingzhong's metal structure from the outermost surface to a depth of G.1 mm is preferred. GS: y20 martensite phase with an area of 0/0. ^ The surface coating degree refers to 〇. · 1mm and 0.55mm, but not limited to these. These digital households have a depth of 1φm and 0.55mm, and the depth is increased or decreased by 0.05mm. In the present invention , Zuo Bai ~ The hard anti-season father ’s surface with a depth of at least 3.0 mm or more is 5 5 HR Γ1 bucket, $. Of ^ 氐. At a depth of 3 mm or more from the outermost surface-or later Called "the core part of the part,". According to the present invention, the part is provided with a core of 4 points, "Toughness guarantee reduces the soil applied to the part, and improves fatigue resistance. Steel is used as the material of parts. -Initially, low carbon is preferred. In the above invention, the iron alloy of Buddha is made. . · No gold parts are preferably made of the following chemical composition button ^ _ alloy parts are preferably made of-an iron alloy material (SCM: chromium_
銷鋼）製成，以質量計 料 W(SCM 4材枓至少包含C: 〇.1〇胃〇 5〇%，Si : 1224143 0.1-0.35%，Μη : 0.60-1.00%，Cr : 0,90- 1.20%，Mo : 〇_ΐ5· 0.45%，其餘為Fe和不邛避免的雜質。以質量計，鐵合金更 佳包含P : 0.030%或更少，S : 0·030%或更少，Ni : 〇.25% 或更少，Cu : 0.30%或更少’及1 0 PPm或更少的氧。 在以上本發明中，鐵合金零件較佳由一種鐵合金材料 (SMn :錳鋼）製成，以質量計，該材料至少包含<：:〇.3〇-0.50%，Si : 0.15-0.35% ’ Mn : 1.2(M.65%，Cr : 〇.7〇 或更 少，其餘為Fe和不可避免的雜質。 在以上本發明中，鐵合金零件可由一種鐵合金材料（Scr : 鉻鋼）製成，以質量計，該材料至少包含c : 0.28-0.48%，Si : 0· 15-0.3 5% ’ Μη : 0.60-0.85% ’ Cr : 0.90-1.20%，其餘為 Fe 和不可避免的雜質。 鐵合金零件較佳由一種鐵合金材料（SNc :鎳-鉻鋼）製成， 以質量計’該材料至少包含C: 〇.32-〇.4〇%，Si: 〇. :15-0.35%， Μη · 0.35-0.80%，Ni · 1.00-3.50%，Cr : 0.50-1.00%，其餘 為Fe和不可避免的雜質。 鐵合金零件較佳由一種鐵合金材料（SN(：m :鎳_鉻_鉬鋼） 製成，以質量計，該材料至少包含c : 〇.2〇-〇.5〇%，Si : 0.15-0.35%，Μη : 0.35-1.00% , Ni : 〇·4〇_3 5〇%，Cr : 0·40-3·50%，Mo : 0·15-0.70%，其餘為以和不矸避免的雜 質。 更確切而口，可使用具有圖9中所示化學組成之鐵合金。 以上鐵合金材料中所含的元素將單獨描述。 10 丄 C(%i)為改良鋼硬度 . 艰及所必需的一種兀素。在本菸明 中，碳濃度應低到給予零件核糧度。 ^ (夕）”叉相似，為增加鋼硬度和強度的一種 發明之鐵合金包含0.1至。.35%之Si。 ，、 二錳)加入用於改良鋼的強度及硬化能力，且為有效作 鋼中除氧所用脫氧劑的—種元素。Μη亦為能夠給予鋼動 度的一種元素。本發明之鐵合金包含。.3。至1.65%之廷。 )為種加入以改良鋼的硬化能力及促進滲碳之元 素。 氮）為由錢化處理溶於鋼之元素。在本發明中，有〇5〇 〃里或更少氮在自最外表面〇·55毫米之深度溶於金屬結 構以改良令件表面之硬度及抗疲勞性。 .鐵合金基本包含以上化學成分，且在需要時可包含Μ。和 '。Μο(鉬)為抑制晶粒間界氧化物層形成並用於改良鋼硬 月匕力的種元素。Νι為改良鋼章刃度的一種元素。 A在鋼包含大量p(磷）、S(硫）、〇(氧）或Cu(銅）時’鋼的性 能降低。因此，太蘇昍斗 ^ 鐵5至只包含較少量此等元素。尤 其用0(乳）判斷鋼的品質。f規鋼包含至少2〇啊的氧。然 在本1月中使用包含不大於1〇 氧之高純鋼。 下步描述製造本發明鐵合金零件之方法。 ^造本發明鐵合金零件之方法包括，使—由鐵合金製成 的零件在高碳濃度氣體中經過滲碳處理，並在碳氮化氣體 中經過碳氮化處理’該鐵合金至少包含C : 〇 1〇_〇 5〇%，si : 1 0.35/。Mn . 0.35- 1.65% ’ Cr : 0.40-3.50%，ppm 或 1224143 更少氧，其餘為Fe和不可避免的雜質。 根據本發明，使包含不大於1 〇 ppm氧之低碳、高純度鋼 零件經過第一滲碳處理，然後經碳氮化處理。藉由組合渗 藏處理及碳氮化處理，在零件表面沈澱微細碳化物顆粒， 且氮溶於其中，以改良該零件表面的硬度及抗疲勞性。 在以上製造方法中，第一滲碳處理較佳在900至97〇qc範 圍之溫度進行。此係因為，當滲碳處理溫度超過97(rc時發 生晶粒間界氧化反應，且奥氏體顆粒變大，而當滲碳處理 溫度低於90(TC時滲碳之量降低。滲碳處理後的冷卻速率較 佳低於臨界冷卻速率，以使碳能夠在轉化前分散於奥氏體 中。因此，高級低共熔珍珠體結構沈澱，且沒有馬丁體結 構生成。 第一碳氮化處理較佳在8〇〇至8401範圍之溫度進行。此 係因為，當碳氮化處理溫度超過84〇t時在晶粒間界保留的 竣化物再次完全溶解，而氮不溶解，而在碳氮化處理:度 低於刪。C日寺’使碳化物球化需要長時間，且生產率降低^ ，在本發明中’滲碳處理-次進行。然而，滲碳處理不限 =^/入：可進行多次’只要零件表面的金屬結構和其中所 含氮之量由組合滲竣及錢化處理最m本文中所規定 L貫施万式】 ::圖1至圖8’以後說明鐵合金零件並以將 應用於曲柄銷作為車輛或 “牛 鐵合金手托以丨^科為㈣明製造 12 1224143 圖1顯示一曲柄銷。圖1(a)為一曲柄銷【 為沿圖1(a)中線A-A’切取的橫截面圖’圖丨θ圖l(b) 線B-B，切取的橫截面圖。曲柄銷1為連接曲柄二圖广)中 之零件，並具有壓.配入曲柄轴之末端以及 連杆所用 連接到連杆之中間部分。 來針軸承 曲柄銷由包括圖2中所示步驟之方法製造。 !;#一種鐵合金材料(步驟…並將該鐵合金材:研= :(=相油孔後，將鐵合金材料•孔(步驟 ”、、後，自鐵合金材料除去毛刺（步驟4)。 將鐵合金材料的外周邊粗略抛光（步驟5) :經過第-渗竣處理(步驟6)。然後使鐵合金材料二材 妷氮化處理（步驟7)。 弟一 最後’使鐵合金材料經相火處理（步驟8)，並使 面經過最後抱光處理（步驟9)，由此得到曲柄銷。 =製造曲柄銷製程中的第_渗碳處理和第二碳氮化處理 在圖3中所示條件下進行。 、如圖3⑷中所示，第-渗碳處理在· t-95(TC範圍之溫 二4:小時範圍之滲碳時間及°·7至1.5範圍之CP(碳勢)條 件下進行。在第一滲碳處理後，將鐵合金材料在_铺 保持0.5至1.〇小時’並在加熱爐中冷卻。，然後在_1請 c範圍山之溫度、w小時範圍之碳氮化時間、〇 8至13範圍 ^ (人勢）及3 ·〇升/为叙或更低之氨流速條件下進行第二碳 乳化處理。在第二竣氮化處理後’在無進一步渗碳和碳氮 乍用下於1 90 C進行回火熱處理。渗碳處理和碳氮化處理 13 1224143 不是必需在圖3 (a)所+ /，欠^ τ I j /Γ τΜ巾件下進行，可在圖3所示的條件 下進行。如圖3(b)中所μ ’Τ听不吊一滲碳處理在900-950°C範圍 < /皿度4-6小時圍之滲碳時間及〇7至丨.5範圍之cp(碳勢） ，、件下進仃。然後將鐵合金材料在爐中冷卻。隨後，在_ C 87 0 C la圍之溫度、小時範圍之碳氪化時間、㈣至丨,3 fc圍之CP(^勢)及3·〇升’分鐘或更低之氨流速條件 下進行第 二碳氮化處理。在碳氮化處理後，在無進一步滲碳和碳氮Pin steel), made of W by weight (SCM 4 material: at least C: 〇.10 〇 stomach 〇50%, Si: 1224143 0.1-0.35%, Mn: 0.60-1.00%, Cr: 0,90 -1.20%, Mo: 〇_ΐ5 · 0.45%, the rest are Fe and unavoidable impurities. On a mass basis, ferroalloys preferably contain P: 0.030% or less, S: 0.030% or less, Ni : 0.25% or less, Cu: 0.30% or less' and 10 PPm or less oxygen. In the above invention, the ferroalloy part is preferably made of an iron alloy material (SMn: manganese steel), On a mass basis, the material contains at least < :: 0.30-0.50%, Si: 0.15-0.35% 'Mn: 1.2 (M.65%, Cr: 0.70 or less, the rest being Fe and Inevitable impurities. In the above invention, the ferroalloy part may be made of a ferroalloy material (Scr: chrome steel), and by mass, the material contains at least c: 0.28-0.48%, and Si: 0 · 15-0.3 5% 'Μη: 0.60-0.85%' Cr: 0.90-1.20%, the rest is Fe and unavoidable impurities. Ferroalloy parts are preferably made of a ferroalloy material (SNc: nickel-chrome steel), by mass' the material is at least Contains C: 〇.32- .40%, Si: 〇 .: 15-0.35%, Mn · 0.35-0.80%, Ni · 1.00-3.50%, Cr: 0.50-1.00%, and the rest are Fe and unavoidable impurities. Ferroalloy parts are preferably made of An iron alloy material (SN (: m: nickel_chromium_molybdenum steel) made of, by mass, the material contains at least c: 0.20-0.50%, Si: 0.15-0.35%, Mn: 0.35 -1.00%, Ni: 0.4.50-35%, Cr: 0.4-40-3.50%, Mo: 0.15--0.70%, and the rest are impurities to avoid. An iron alloy having the chemical composition shown in Fig. 9 can be used. The elements contained in the above iron alloy materials will be described separately. 10 丄 C (% i) is an improved steel hardness. It is a necessary element in this cigarette. In the Ming Dynasty, the carbon concentration should be low enough to give the part a nuclear grain. ^ (Xi) "Fork similar to the iron alloy of an invention to increase the hardness and strength of the steel contains 0.1 to .. 35% of Si., Dimanganese) added It is an element that improves the strength and hardening ability of steel and is effective as a deoxidizer for deoxidation in steel. Mn is also an element that can impart steel dynamics. The iron alloy of the present invention contains .3 to 1.6 5% court.) Is an element added to improve the hardening ability of steel and promote carburization. Nitrogen) is an element that dissolves in steel due to money treatment. In the present invention, nitrogen of 0.50 Torr or less is dissolved in the metal structure at a depth of 0.55 mm from the outermost surface to improve the hardness and fatigue resistance of the surface of the part. The iron alloy basically contains the above chemical composition, and may include M when necessary. with '. Mo (molybdenum) is an element that suppresses the formation of an oxide layer at the grain boundary and is used to improve the strength of steel. Ni is an element that improves the sharpness of the steel chapter. A's performance decreases when the steel contains a large amount of p (phosphorus), S (sulfur), 0 (oxygen), or Cu (copper). Therefore, Taisu 昍 铁 Iron 5 contains only a small amount of these elements. Especially 0 (milk) is used to judge the quality of steel. F gauge steel contains at least 20 Ah. However, in this January, high-purity steel containing no more than 10 oxygen is used. The next step describes the method of manufacturing the ferroalloy part of the present invention. ^ The method for manufacturing the ferroalloy part of the present invention includes:-making a part made of a ferroalloy through a carburizing treatment in a high carbon concentration gas and a carbonitriding treatment in a carbonitriding gas; the ferroalloy contains at least C: 〇1 〇_〇50 ％, si: 1 0.35 /. Mn. 0.35- 1.65% ’Cr: 0.40-3.50%, ppm or 1224143 less oxygen, the rest is Fe and unavoidable impurities. According to the present invention, a low-carbon, high-purity steel part containing no more than 10 ppm oxygen is subjected to a first carburizing treatment and then a carbonitriding treatment. By combining infiltration treatment and carbonitriding treatment, fine carbide particles are precipitated on the surface of the part, and nitrogen is dissolved therein to improve the hardness and fatigue resistance of the surface of the part. In the above manufacturing method, the first carburizing treatment is preferably performed at a temperature in the range of 900 to 97 ° c. This is because the grain boundary oxidation reaction occurs when the carburizing treatment temperature exceeds 97 (rc), and austenite particles become larger, while the carburizing amount decreases when the carburizing treatment temperature is lower than 90 (TC. Carburizing). The cooling rate after treatment is preferably lower than the critical cooling rate, so that carbon can be dispersed in austenite before conversion. Therefore, the higher eutectic pearlite structure is precipitated and no martensite structure is formed. First carbonitriding The treatment is preferably performed at a temperature in the range of 800 to 8401. This is because when the carbonitriding treatment temperature exceeds 840,000 t, the final compound retained at the grain boundary is completely dissolved again, while nitrogen is not dissolved, and the carbon Nitriding treatment: the degree is lower than that. C Risi 'takes a long time to spheroidize carbides and reduces productivity ^ In the present invention,' carburizing treatment is performed once. However, carburizing treatment is not limited = ^ / 入: Can be performed multiple times as long as the metal structure on the surface of the part and the amount of nitrogen contained in it are completed by combination infiltration and money treatment. The L-type method is specified in this article] :: Figure 1 to Figure 8 Parts and will be applied to the crank pin as a vehicle or The hand rest is made by 科科 ㈣㈣ 明 12 1224143 Figure 1 shows a crank pin. Figure 1 (a) is a crank pin [is a cross-sectional view taken along the center line A-A of FIG. 1 (a) ' θ Figure l (b) is a cross-sectional view taken along line BB. The crank pin 1 is a part connected to the crank two, and has pressure. Fitted into the end of the crank shaft and the middle part of the connecting rod used to connect to the connecting rod The needle bearing crank pin is manufactured by a method including the steps shown in FIG. 2; ## An iron alloy material (step ... and the iron alloy material: ground =: (= phase oil hole, the iron alloy material • hole (step ", And then, remove the burrs from the ferroalloy material (step 4). Roughly polish the outer periphery of the ferroalloy material (step 5): go through the -infiltration completion treatment (step 6). Then, the second material of the ferroalloy material is nitrided ( Step 7). First, 'the ferroalloy material is subjected to phase fire treatment (step 8), and the surface is subjected to the final buffing treatment (step 9), thereby obtaining the crank pin. = Carburizing in the manufacturing process of the crank pin The treatment and the second carbonitriding treatment are performed under the conditions shown in FIG. 3. As shown in FIG. The treatment is carried out under the conditions of t-95 (temperature in the TC range 4: hour range and CP (carbon potential) in the range of ° 7 to 1.5). After the first carburizing treatment, the iron alloy material is Store for 0.5 to 1.0 hours' and cool in a heating furnace. Then, the temperature in the range of 1 ° C, the carbonitridation time in the range of w hours, the range of 8 to 13 ^ (human potential), and 3 · 0 liters per second or less under the condition of ammonia flow rate. After the second nitriding treatment, the tempering heat treatment is performed at 1 90 C without further carburizing and carbonitriding. The carbon treatment and carbonitridation treatment 13 1224143 need not be performed under the condition shown in FIG. 3 (a) + /, ≦ τ I j / Γ τM, and may be performed under the conditions shown in FIG. 3. As shown in Fig. 3 (b), the carburizing treatment in the range of 900-950 ° C < / ° 4-6 hours and the carburizing time in the range of 0-7 to 0.5 (Carbon potential). The ferroalloy material is then cooled in a furnace. Subsequently, under the conditions of the temperature of _ C 87 0 C la, the carbonization time in the hour range, the CP (^ potential) of 3 to 3 fc, and the ammonia flow rate of 3.0 liter's or less The second carbonitriding treatment. After carbonitriding, no further carburizing and carbonitriding
化作用下於1 9Gt進行回火熱處理。在製造連杆製程中的第 /參石灭處理和第二碳氮化處理在圖3(a)中所示條件下進 行0Tempered at 19 Gt under chemical reaction. The first and second carbonitriding treatments in the manufacturing process of the connecting rod are performed under the conditions shown in FIG. 3 (a).
如圖3⑷中所不’第一滲碳處理在900°C -950°C範圍之溫 度' 4-6小時範圍之滲碳時間及〇·7至15範圍之碳勢）條 件下進行。在第一滲碳處理後，將鐵合金材料在8〇〇_9〇〇。〔 保持0.5土 ΐ·〇小時’並在加熱爐中冷卻。然後在刚。㈣ c範圍之溫度、u小時範圍之碳氮化時間、範圍 (CP(後勢）及3·〇升/分鐘或更低之氨流速條件下進行第二碳 虱化處理。在第二碳氮化處理後，在無進一步滲碳和碳氮 化作用下於190 c進行回火熱處理。滲碳處理和碳氮化處理 不是必需在圖3(a)所示條件下進行，可在圖3(b)中所示條件 下行如圖3(b)中所示，第一滲碳處理在9〇〇-95〇QC範圍 心溫度、4-6小時範圍之滲碳時間及〇 7至丨·5範圍之cp(碳勢） 餘件下進行。然後將鐵合金材料在爐中冷卻。隨後，在8⑼ C 8 7 0 C範圍之/JGL度、1 · 3小時範圍之碳氮化時間、〇. 8至1.3 範圍之CP(碳勢）及3.0升/分鐘或更低之氨流速條件下進行第 14 1224143 二碳氮化處理。在碳氮化處理後，在無進一步滲碳和碳氮 化作用下於1 9 〇 °C進行回火熱處理。 、製坆下文所7F的以下實例和比較性實例之試件。觀察各 试件&金屬結冑’並檢驗試件的硬度、抗疲勞性及高溫抗 軟化性。各試件具有6〇1毫米之外徑、2〇•丨毫米之内徑及91 毫米之厚度。 實例（表1，試件1) 在本貫例中使用一種如表1中所示的鐵合金（鉻-鉬鋼 (SCM)) ’以貝f计’該鐵合金包含匚：〇 18_〇.23〇/。，si : 0·15-0·35% ’ Μη : 〇·6〇-〇·85% ’ p : 〇 〇3%或更少，s : 〇 〇3% 或更少，他.0.25%或更少，（>:〇9〇-1.2〇%，^1〇:〇15-〇3〇%，As shown in Fig. 3 (a), the first carburizing treatment is performed under the conditions of a temperature ranging from 900 ° C to 950 ° C, a carburizing time ranging from 4 to 6 hours, and a carbon potential ranging from 0.7 to 15). After the first carburizing treatment, the ferroalloy material is placed at 800-900. [Hold for 0.5 ΐ · 0 hours' and cool in a heating furnace. And then just now.第二 The second carbon lice treatment is performed under the conditions of the temperature in the c range, the carbonitridation time in the u range, the range (CP (back potential), and an ammonia flow rate of 3.0 liters / minute or lower. After the chemical treatment, tempering heat treatment is performed at 190 c without further carburizing and carbonitriding. Carburizing and carbonitriding are not necessarily performed under the conditions shown in Fig. 3 (a), but can be performed in Fig. 3 (a). The conditions shown in b) are as shown in FIG. 3 (b). The first carburizing treatment has a core temperature in the range of 900-950QC, a carburizing time in the range of 4-6 hours, and 0-7 to 5 The cp (carbon potential) of the range is performed under the remaining pieces. Then the ferroalloy material is cooled in the furnace. Subsequently, the carbonitriding time in the range of 8⑼ C 8 7 0 C / JGL degree, the carbon nitriding time in the range of 1.3 hours, 0.8 No. 14 1224143 carbonitriding treatment under conditions of CP (carbon potential) in the range of 1.3 and ammonia flow rate of 3.0 liters / minute or less. After carbonitriding treatment, without further carburizing and carbonitriding Tempering heat treatment was performed at 190 ° C. Test pieces of the following examples and comparative examples of 7F described below were prepared. Observe each test piece & The hardness, fatigue resistance, and softening resistance of the test piece. Each test piece has an outer diameter of 601 mm, an inner diameter of 20 mm, and a thickness of 91 mm. Examples (Table 1, Test piece 1) are in This example uses an iron alloy (chromium-molybdenum steel (SCM)) shown in Table 1 'in terms of f'. The iron alloy contains 匚: 〇18_〇.23〇 /, si: 0 · 15- 0.35% Μη: 0.60-0.85% 'p: 0.003% or less, s: 0.003% or less, he .0.25% or less, (>: 〇 90-1.2%, ^ 10: 〇15-〇3%,
Cu · 0.3%或更少，1〇 ppm或更少的〇（氧），其餘為“和不 可避免的雜質。更確切而言，製備如表1中所示的鐵合金材 P : 0.013% 或更少，S : 0.007% 或更 ’ Cr : 1.13%，Mo ·· 0-15%，Cu : 0.10%， 其餘為Fe和不可避免的雜質。 料之試件’以質量計，該鐵合金材料包含C ·· 0.20%，Si : 0.23% J Μη ： 0.83% 少，N i ·· 0 · 〇 7 %或更少 6ppm或更少的〇（氧） 15 表1 實例 試件1 C 0.18-0.23 0.20 Si 0.15-0.35 0.23 Μη 0.60-0.85 0.83 Ρ 0.030或更少 0.013 化學組成 S 0.030或更少 0.007 (質量％) Ni 0.25或更少 0,07 Cr 0.90-1.20 1.13 Mo 0.15-0.30 0.15 Cu 0.030或更少 0.10 〇（ppm) 1 0 ppm或更少 6 ppm 1224143 在圖3(a)所示條件下使試件經過滲碳處理及碳氮化處 理。如此獲得的試件被稱為試件1。 __ 16 1224143 表1 a S偁 化學纟a成 (' Si Μη P S \| (1 \丨‘， SMn 420H SMn 2IH 0 I6~0 23 0 15-0 35 1 15-I 55 0 030或史小 U 0’⑴或更小 SMn 4V、H SMn IH 0 29-0 36 0 1 >-〇 丨 15' 1 ^ 0 0)0或史小 <* (⑸)成圯小 SMn 438H SMn 2H 0.34-0 41 0.15-0.35 1.30-1.70 0.030或史小 0 030或史小 — — SMn 443H SMn 3H 0.39-0.46 0.15-0 35 1.30-1 70 0.030或更小 0030或更小 一 一 — SMnC 420H SMnC 2IH 0 16-0.23 0 15-0.35 1.15-1.55 0.030或更小 0.030或更小 — 0.35-0.70 — SMnC 443H SMn 3H 0.39-0 46 0.15-0.35 1.30-1.70 0.030或更小 0.030或更小 — 0.35〜0 70 — SCr 415H SCr 2IH 0 12-0 18 0 15〜0.3 5 0 55-0.90 0 030或更小 0 030或更小 _ 0 85-1.25 — SCr 420H SCr 22H 0 17-0.23 0 15〜0.35 0 55-0 90 0.030或更小 0 030或更小 U 1 SCr 430H SCr 2H 0.27 〜0.34 0.15〜0.35 0.55-0.90 0.030或更小 0 030或更小 — 0 85-1 ：5 — SCr 435H SCr 3H 0.32-0.39 0.15 〜0.35 0.55-0.90 0.030或更小 0Λ)30或更小 -— 0 85-1 ：5 SCr 440H SCr 4H 0.37 〜0 44 0 15-0 35 0 55〜0 90 0 030或更小 0 030或更小 .... 0 1 ：> SCM 4I5H SCM 2IH 0.12Ό 18 0 15〜0 35 0 55-0 00 0.030或史小 0 0：!0或更小 0 85-1:; u 15 -π SCM 4I8H SC- 0 15-0 21 0 15-0.35 0.55-0 90 0030或更小 0 030或史小 0 85-1 25 0 15-0 35 SCM 420H SCM 22H 0.17-0 23 0 15-0 35 0 55-0.90 0Ό30或更小 0().10或更小 — 0 -1 0 |> () SCM 435H SCM 3H 0.32Ό.39 0.15-0.35 0.55-0.90 0.030或更小 0.030或更小 — 0.85-1 25 0 15 -0 35 SCM 440H SCM 4H 0.37-0.44 0 15-0.35 0.55-0.90 0.030或更小 0.030或更小 一 0.85-1.25 0.15-0.35 SCM 445H SCM 5H 0.42-0.49 0.15 〜0.35 0.55 〜0.90 0.030或更小 0.030或更小 一 0.85-1.25 0 15-0 35 SCM 822H SCM 24H 0.19-0.25 0.15-0.35 0.55-0.90 0.030或更小 0.030或更小 一 0.85-1 25 0.35-0 45 SNC 4I5H SNC 2IH 0.11-0.18 0.15-0.35 0.30-0.70 0.030或更小 0030或更小 1.95-2.50 0 20-0 65 — SNC 63IH SNC 2H 0.26-0.35 0.15-0.35 0.30 〜0.70 0.030或更小 0 030或更小 145Ί 00 0 55-1 05 SNC 815H SNC 22H 0.1 ΙΌ. 18 0.15-0.35 0.30-0.70 0.030或更小 0 030或更小 2 95-3 50 0 65-1 U5 SNCM 220H SNCM 2IH 0 I7~0 23 0 15-035 0 60-0 95 0 030或更小 (V030或史小 0 ."!5-〇 7> 0 0 | > 0 }() SNCM 420H SNCM 23H 0 17-0 23 0 15-0 35 0 40-0 70 0.030或更小 0 030或史小 丨55〜2 00 0 35-0 65 0 15-0 30 比較性實例1(試件2和3) 將經過第一滲碳處理而未經第二碳氮化處理之試件指定 為試件2和3。第一滲碳處理以與實例相同之方式進行。 將具有與實例中試件1所用鐵合金相同之化學組成之鐵合 金用於試件2，而具有SCM 435H化學組成之鐵合金（見圖9) 用於試件3。 比較性實例2(試件4) 製備表面上無碳化物沈澱之試件。更確切而言，使用具 17 有與貫例中試件i所用鐵合金材料相同之化學組成之鐵合金 材料’第一滲碜處理在不導致碳化物沈澱之氣體中進行。 第二碳氮化處理未進行。 比較性貫例3 (試件5) 用具有與實例中所用鐵合金材料相同之化學組成之鐵合 金材料製備試件。使該試件經過第一滲碳處理及第二碳氮 化處理。第二碳氮化處理在不同於實例中的條件下進行， 以製備具有包含〇.5%或更多氮之表面金屬結構之試件。第 一渗碳處理用與實例相同之方式進行。 比較性實例4 (試件6) 製備表面結構中沈殿具有大於5微米平均直徑碳化物之試 件。更確切而t ’使用具有與實例中所用鐵合金材料相同 ，化學組成之鐵合金材料，她于第—滲碳處理及第二碳 氮化處理。第一滲碳處理在不同條件下進行。 比車父性實例5 (試件7) 〜 用“包含20 ppm或更多氧之鐵合金材料但不用處理除去氧 k減件7。其他條件均與實例中相同。 入對實例和比較性實例⑴中得到的試件丨幻進行硬度檢 知、X射線煢光分析及滾動疲勞檢驗。 外試㈣行硬度檢驗。在硬度檢驗中，檢驗在自最 約0.55 *米深度之威克（Wickers)硬度。因土 有實例和比較性實例的試件巾’自最外表面此二所 深度之表面展現700 HV或更高硬度。 ·笔未之 度，則進行洛氏（Rockwell)硬度檢測。會例和勺^刀硬 八 Μ比較性實例之 18 1224143 試件均顯示5 5 HRC或更低之硬度。 然後使試件經過X射線發光分析，以元素分析其中所含的 0。X-射線熒光分析用具有10毫米Ε(^ΧΙΙΡΜ700進行。 結果，在試件1、4、6和7中，在自最外表面〇·55毫米區域 中包含0 · 5 5 %或更少的氮，而試件2和3中不含氮。在試件5 中包含大量氮。試件7包含約20 ppm氧，而其他試件包含 PPm或更少的氧。通常，鋼包含約2〇 ppm氧。然而，在本發 明中’滲碳處理和碳氮化處理後的氧含量由減少所用鐵合 金材料中氧量顯著降低。 進仃滾動疲勞檢驗用以研究抗疲勞性和高溫抗軟化性。 滾動疲勞檢驗用圖4中所示檢驗裝置5進行。將試件7和鋼球 8固疋在含潤滑油6的外來物體中。由加熱器9將潤滑油$加 热到任意溫度，並固定試件7，以便通過3個鋼球8自上和下 對試件施加壓縮力。然後旋轉軸10，同時自上和下對試件7 她加壓纟侣力。當軸1 0旋轉時，鋼球8以試件7的圓周方向旋 轉，以便恰在鋼球8下對試件7施加最大壓縮負荷。因此， :Λ、牛7施加的負荷隨鋼球8接近而增加，並隨鋼球8離開而 奪低且一旦軸10旋轉時，對試件7重複施加負荷3次。利 用^ ^裝置6 ’對試件！和、2和3進行滾動疲勞檢驗。滾動 疲勞祆驗在環境溫度用具有以i克/升之量混於潤滑油的高 =、·岡粕末（顆粒大小：1〇5至15〇，硬度：、6〇至8〇〇 的潤 π ’由王軸#60作為外來物、在5292兆帕最大軸承壓力和18〇〇 、、車旋速度之條件下進行。將試件在2〇〇。〔回火卜】、時， 並放入環境溫度已於約2⑽。C使用的相同情形。結果顯示於 19 1224143 表5中。在圖5中，水平軸代表 古土、 也加應力的次數（周期），而垂 直軸代表累積破裂概率（〇/。）。比私 &在50%累積破裂概率的值， 經過碳氮化處理兩次的試件1 |缸截， 、旰1要耗費1.59Χ1〇6次，且與試件 2和j比車父具有較南抗疲勞性， A件2和3耗費ι·〇2 X 1〇6次和 7·95 X 1〇5次，如圖5中所示。 拍攝龍像用於研究其金屬結構。圖6為在·倍放大率 下拍攝的在自最外表面約(M毫米深度試件i之金屬結構之 電子顯微像。如圖6中所示，碳化物丨丨均勻分散並具有5微 米或更小微細顆粒大小。SEM*析顯示，該金屬結構包含3〇 面積。/。或更少由碳化物η組成的碳化物相、20面積％或更少 馬丁相及50面積％或更少保留的奥氏體相。在比較性實例2 的試件4之金屬結構中未觀察到碳化物。此係因為第一滲碳 處理的滲碳氣體具有低濃度。 如實例和比較性實例中所示，根據該具體實施例，進行 為第一滲碳處理和第二碳氮化處理組合之表面處理，以形 成這€ 種金屬結構’其中有碳化物沈;殿並包含氮且在自 最外表面0.1毫米深度區域包括至少5 〇面積。/。或更少保留的 奧氏體相及3 0面積％或更少碳化物相。零件由此具有高表面 硬度及改良的抗疲勞性。此外，該零件在自最外表面〇. 5毫 米之深度具有至少700 HV之硬度及55 HRC或更低的核硬 度，因此，其具有極佳内韌度。因而，即使對零件表面施 加壓縮應力，仍可減輕零件内的壓縮應力。因此，能夠獲 得具有高硬度和較佳抗疲勞性之鐵合金零件。 雖然在此具體實施例中本發明之鐵合金零件應用於車輛 20 或摩托的曲柄銷’但本發明並不限於此。例如，可將本發明 义鐵合金零件應用於其他施加壓縮負荷的零件，如圖7中所 示的曲柄軸9或圖8中戶斤*的連杆1〇。此夕卜，本發明之鐵合全 零件亦可應用於需要高硬度、高抗疲勞性和極佳高溫抗軟化 性之零件。 [發明效果] 如上所述，根據本發明，可藉由形成具有規定金屬結構和 其中沈澱碳化物且包本舞的矣而禮p 3 士丄 η虱的表面獲侍具有高硬度、極佳抗疲 分性和高溫抗軟化性之灾株。阴ψ pa ^ f炙令件因此，即使為施加壓縮負荷之 令件，仍可改良零件的使用壽命。 【圖式簡單說明】 圖1⑷-⑷為顯示一實施例之曲柄銷之視圖。 圖2為顯7F曲柄銷製造程序之流程圖。 ==(13)為說明進行第_滲碳處理和第二碳氮化處理之 處理條件（視圖。 圖圖4為說明滾動抗疲勞檢驗所用檢驗裝置之側視橫截面 結果 社喂境溫度對試件 J疋仃淡動疲勞檢 圖6為顯示在自其最外表面 结構之放大像。 度之試们之金屬 圖7為鐵合金零件能夠應用的曲—之橫截面圖。 圖8為鐵合金零件能夠應用的連 ^止視圖。 圖9為顯示用於本發明鐵合金 成圖。 千〈鐵合金材料之化學組 21 1224143 【圖式代表符號說明】 1 曲柄銷 2 檢驗裝置 3 潤滑油 4 試件 5 鋼球 6 加熱器 7 軸 8 碳化物 9 曲柄車由 10 連杆Cu · 0.3% or less, 10 ppm or less of 0 (oxygen), and the rest are "and unavoidable impurities. More precisely, the ferroalloy material as shown in Table 1 was prepared P: 0.013% or more Less, S: 0.007% or more, Cr: 1.13%, Mo · 0-15%, Cu: 0.10%, and the rest are Fe and unavoidable impurities. The test piece is expected to be mass-based, and the iron alloy material contains C ·· 0.20%, Si: 0.23% J Μη: 0.83% less, Ni · · 0 · 〇7% or less 6ppm or less 〇 (oxygen) 15 Table 1 Example test piece 1 C 0.18-0.23 0.20 Si 0.15-0.35 0.23 Mn 0.60-0.85 0.83 P 0.030 or less 0.013 Chemical composition S 0.030 or less 0.007 (mass%) Ni 0.25 or less 0,07 Cr 0.90-1.20 1.13 Mo 0.15-0.30 0.15 Cu 0.030 or less 0.10 〇 (ppm) 10 ppm or less 6 ppm 1224143 The test piece was subjected to carburizing treatment and carbonitriding treatment under the conditions shown in FIG. 3 (a). The test piece thus obtained is referred to as test piece 1. __ 16 1224143 Table 1 a S chemistry 纟 a 成 ('Si Μη PS \ | (1 \ 丨', SMn 420H SMn 2IH 0 I6 ~ 0 23 0 15-0 35 1 15-I 55 0 030 or Shi Xiao U 0 '⑴ or Small SMn 4V, H SMn IH 0 29-0 36 0 1 > -〇 丨 15 '1 ^ 0 0) 0 or Shi Xiao < * (⑸) 成 圯 小 SMn 438H SMn 2H 0.34-0 41 0.15-0.35 1.30-1.70 0.030 or Shi Xiao 0 030 or Shi Xiao — SMn 443H SMn 3H 0.39-0.46 0.15-0 35 1.30-1 70 0.030 or less 0030 or less one — SMnC 420H SMnC 2IH 0 16-0.23 0 15 -0.35 1.15-1.55 0.030 or less 0.030 or less — 0.35-0.70 — SMnC 443H SMn 3H 0.39-0 46 0.15-0.35 1.30-1.70 0.030 or less 0.030 or less — 0.35 ~ 0 70 — SCr 415H SCr 2IH 0 12-0 18 0 15 ~ 0.3 5 0 55-0.90 0 030 or less 0 030 or less_ 0 85-1.25 — SCr 420H SCr 22H 0 17-0.23 0 15 ~ 0.35 0 55-0 90 0.030 or less Small 0 030 or less U 1 SCr 430H SCr 2H 0.27 to 0.34 0.15 to 0.35 0.55-0.90 0.030 or less 0 030 or less — 0 85-1: 5 — SCr 435H SCr 3H 0.32-0.39 0.15 to 0.35 0.55- 0.90 0.030 or less 0Λ) 30 or less-0 85-1: 5 SCr 440H SCr 4H 0.37 to 0 44 0 15-0 35 0 55 to 0 90 0 030 or less 0 030 or less ... . 0 1: > SCM 4I5H SCM 2IH 0.12Ό 18 0 15 ~ 0 35 0 55 -0 00 0.030 or history small 0 0:! 0 or less 0 85-1 :; u 15 -π SCM 4I8H SC- 0 15-0 21 0 15-0.35 0.55-0 90 0030 or history 0 030 or history Small 0 85-1 25 0 15-0 35 SCM 420H SCM 22H 0.17-0 23 0 15-0 35 0 55-0.90 0Ό30 or less 0 (). 10 or less — 0 -1 0 | > () SCM 435H SCM 3H 0.32Ό.39 0.15-0.35 0.55-0.90 0.030 or less 0.030 or less — 0.85-1 25 0 15 -0 35 SCM 440H SCM 4H 0.37-0.44 0 15-0.35 0.55-0.90 0.030 or less 0.030 or less-0.85-1.25 0.15-0.35 SCM 445H SCM 5H 0.42-0.49 0.15 ~ 0.35 0.55 ~ 0.90 0.030 or less 0.030 or less-0.85-1.25 0 15-0 35 SCM 822H SCM 24H 0.19-0.25 0.15- 0.35 0.55-0.90 0.030 or less 0.030 or less-0.85-1 25 0.35-0 45 SNC 4I5H SNC 2IH 0.11-0.18 0.15-0.35 0.30-0.70 0.030 or less 1.030-2.50 0 20-0 65 — SNC 63IH SNC 2H 0.26-0.35 0.15-0.35 0.30 to 0.70 0.030 or less 0 030 or less 145Ί 00 0 55-1 05 SNC 815H SNC 22H 0.1 ΙΌ. 18 0.15-0.35 0.30-0.70 0.030 or less 0 030 Or less 2 95-3 50 0 65-1 U5 SNCM 220H SNCM 2IH 0 I7 ~ 0 23 0 1 5-035 0 60-0 95 0 030 or less (V030 or Shi Xiao 0. &Quot;! 5-〇7 > 0 0 | > 0) () SNCM 420H SNCM 23H 0 17-0 23 0 15-0 35 0 40-0 70 0.030 or less 0 030 or Shi Xiao 丨 55 ~ 2 00 0 35-0 65 0 15-0 30 Comparative Example 1 (Test Pieces 2 and 3) will undergo the first carburizing treatment without The second carbonitrided test specimens were designated as test specimens 2 and 3. The first carburizing treatment was performed in the same manner as in the example. An iron alloy having the same chemical composition as that of the iron alloy used in test piece 1 in the example was used for test piece 2, and an iron alloy having the chemical composition of SCM 435H (see FIG. 9) was used for test piece 3. Comparative Example 2 (Test piece 4) A test piece having no carbide precipitation on the surface was prepared. More specifically, the first infiltration treatment using an iron alloy material having the same chemical composition as that of the iron alloy material used in the test piece i in the conventional example 'is performed in a gas that does not cause carbide precipitation. The second carbonitriding treatment was not performed. Comparative Example 3 (Test piece 5) A test piece was prepared using an iron alloy material having the same chemical composition as the iron alloy material used in the examples. The test piece was subjected to a first carburizing treatment and a second carbonitriding treatment. The second carbonitriding treatment was performed under conditions different from those in the examples to prepare test pieces having a surface metal structure containing 0.5% or more nitrogen. The first carburizing treatment was performed in the same manner as in the example. Comparative Example 4 (Test piece 6) A test piece in which Shen Dian had a carbide having an average diameter larger than 5 m in the surface structure was prepared. More precisely, t 'uses an iron alloy material having the same chemical composition as that of the iron alloy material used in the example, which is subjected to the first carburizing treatment and the second carbonitriding treatment. The first carburizing treatment is performed under different conditions. Than car parent example 5 (test piece 7) ~ Use "ferrous alloy material containing 20 ppm or more of oxygen without removing oxygen k minus piece 7. Other conditions are the same as in the example. Into the pair of examples and comparative examples ⑴ The obtained test specimens were subjected to hardness inspection, X-ray photoanalysis, and rolling fatigue inspection. External tests were conducted for hardness inspection. In the hardness inspection, the Wickers hardness was measured at a depth of about 0.55 * meters. The test piece towels with examples and comparative examples show a hardness of 700 HV or higher from the outermost surface at these two depths. · If it is not within the pen, Rockwell hardness test is performed. Examples and Spoon ^ Knife Hard Eight M Comparative Example No. 18 1224143 The test pieces all showed a hardness of 5 5 HRC or lower. Then the test pieces were subjected to X-ray luminescence analysis to elementally analyze the contained 0. X-ray fluorescence analysis was used for The test was performed with 10 mm ε × ΙΡΜ700. As a result, in test pieces 1, 4, 6, and 7, 0.5 to 55% or less of nitrogen was contained in a region of 0.55 mm from the outermost surface, while test piece 2 Nitrogen is not contained in samples 3 and 3. Nitrogen is contained in a large amount in test piece 5. Test piece 7 contains approx. 20 ppm oxygen, while other specimens contain PPm or less oxygen. Generally, steel contains about 20 ppm oxygen. However, in the present invention, the oxygen content after carburizing and carbonitriding is reduced by the iron alloy material used The amount of oxygen is significantly reduced. The rolling fatigue test is used to study fatigue resistance and high temperature softening resistance. The rolling fatigue test is performed using the testing device 5 shown in Fig. 4. The test piece 7 and the steel ball 8 are fixed in a lubricating state. In the foreign object of the oil 6. The lubricant 9 is heated to an arbitrary temperature by the heater 9, and the test piece 7 is fixed so as to apply a compressive force to the test piece from above and below through the three steel balls 8. Then, the shaft 10 is rotated at the same time She pressurizes the test piece 7 from above and below. When the shaft 10 rotates, the steel ball 8 rotates in the circumferential direction of the test piece 7 so that the maximum compression load is applied to the test piece 7 just under the steel ball 8. Therefore, the load applied by Λ, cattle 7 increases as the steel ball 8 approaches, and decreases as the steel ball 8 leaves, and once the shaft 10 rotates, the load is repeatedly applied to the test piece 3 three times. Using the ^^ 装置 6 ' Test the rolling fatigue of test pieces! And 2, and 3. The rolling fatigue test is used at ambient temperature. There is a mixture of lubricating oil in an amount of 1 g / litre, and 冈 meat powder (particle size: 105 to 150, hardness :, 60 to 800). The king shaft # 60 is used as The foreign matter was carried out under the conditions of a maximum bearing pressure of 5292 MPa and a rotation speed of 180 °. The test piece was placed at 200 ° C [tempering temperature], and the ambient temperature was placed at about 2 ° C. C uses the same situation. The results are shown in 19 1224143 Table 5. In Figure 5, the horizontal axis represents the number of times (period) where the ancient soil was also stressed, and the vertical axis represents the cumulative probability of failure (0 /.). & The value of 50% cumulative rupture probability, the test piece 1 after the carbonitriding treatment twice | Cylinder cut, 要 1 takes 1.59 × 106 times, and it is more southern than the test piece 2 and j Fatigue resistance, A pieces 2 and 3 consume ι · 02 X 106 times and 7.95 X 105 times, as shown in Fig. 5. A dragon image was taken to study its metal structure. Figure 6 is an electron micrograph of the metal structure of the test piece i from the outermost surface, taken at a magnification of *. As shown in Figure 6, the carbides are uniformly dispersed and have a thickness of 5 microns. Fine particle size or smaller. SEM * analysis shows that the metal structure contains 30% area. / Or carbide phase composed of carbide η, 20 area% or less Martin phase and 50 area% or less Retained austenite phase. No carbides were observed in the metal structure of test piece 4 of comparative example 2. This is because the carburizing gas of the first carburizing treatment has a low concentration. As shown in the examples and comparative examples It is shown that according to this specific embodiment, the surface treatment is a combination of a first carburizing treatment and a second carbonitriding treatment to form this type of metal structure, in which a carbide is precipitated; and it contains nitrogen and is from the outermost The 0.1 mm depth area of the surface includes at least 50 area. Or less retained austenite phase and 30 area% or less carbide phase. The part thus has high surface hardness and improved fatigue resistance. In addition, The part is 0.5 mm deep from the outermost surface It has a hardness of at least 700 HV and a core hardness of 55 HRC or lower, so it has excellent internal toughness. Therefore, even if compressive stress is applied to the surface of the part, the compressive stress in the part can be reduced. Therefore, it is possible to obtain Ferroalloy part with high hardness and better fatigue resistance. Although the ferroalloy part of the present invention is applied to a crank pin of a vehicle 20 or a motorcycle in this embodiment, the present invention is not limited thereto. For example, the ferroalloy of the present invention may be The parts are applied to other parts that are subject to compressive load, such as the crank shaft 9 shown in Fig. 7 or the connecting rod 10 of the household weight * in Fig. 8. Furthermore, the iron-all-in-one parts of the present invention can also be applied to the parts requiring high Parts having hardness, high fatigue resistance, and excellent high-temperature softening resistance. [Inventive Effect] As described above, according to the present invention, it is possible to form a present with a predetermined metal structure and carbides precipitated therein. 3 The surface of Shi 丄 lice is served by high-hardness, excellent fatigue resistance, and high-temperature softening resistance. Yin pa pa ^ f 令 order pieces Therefore, even if a compressive load order piece can be improved [Schematic description of the drawings] Figure 1 说明 -⑷ is a view showing the crank pin of an embodiment. Figure 2 is a flowchart showing the 7F crank pin manufacturing process. Processing conditions for carbon treatment and second carbonitriding treatment (view. Fig. 4 is a side cross-sectional view illustrating the inspection device used for rolling anti-fatigue inspection. The results are shown in Figure 6. A magnified image showing the structure from its outermost surface. The metal of the tester Figure 7 is a cross-sectional view of a curve that can be applied to ferroalloy parts. Figure 8 is a continuous view of ferroalloy parts that can be applied. Figure 9 is a display Used for the drawing of the ferroalloy of the present invention. Chemical group of the ferroalloy material 21 1224143 [Description of the symbols of the drawings] 1 Crank pin 2 Inspection device 3 Lubricant 4 Test piece 5 Steel ball 6 Heater 7 Shaft 8 Carbide 9 Crank car By 10 connecting rods