200539971 九、發明說明： 【發明所屬之技術領域】 本發明係關於粉末金屬m特定地，本發明係關於燒 結金屬零件，其具有經密實化之表面及其係適合於苛求之 用途。本發明亦包括一種製備此等金屬零件之方法。 【先前技術】 與全密實鋼（full dense steel)之習用之配對方法比較，經 由使用粉末冶金方法以製造結構零件具有若干利益。如 此，能量消耗係很較低的及材料利用係报較高的。有利於 粉末冶金途徑之另一種重要因素係，具有網形狀或接近網 形狀之組件可係於燒結方法之後直接製造而不需要昂貴之 成形諸如車削、銑、搪孔或磨光。然而，與粉末冶金（pM) 組件比較，通常全密實鋼材料具有較優越之機械性質。因 此，已努力以提高粉末冶金組件之密度，俾能達到儘可能 接近全密實鋼之密度值之值。 於具有高密度之粉末金屬零件之利用中，未來成長之一 領域係於汽車工業中。於此領域中屬於特別重要者係粉末 金屬零件於較苛求應用中之使用，諸如動力傳送應用，例 如，齒輪。相關於經由粉末金屬方法而生成之齒輪之問題 係’與自條料或鍛件製造之齒輪比較，粉末金屬齒輪於該 齒輪之齒根區域中具有降低之彎曲疲勞強度，及於齒腹上 低之接觸疲勞強度。此等問題可係經由齒根之表面及齒腹 區域藉通常以表面密實化作用知曉之方法之塑性變形而減 輕或甚至消除。可使用於此等苛求之應用之產品係於，例 101192.doc 200539971 如’美國專利 5 711 187、5 540 883'5 552 109、5 729 822及6 171 546中敘述。 美國專利5 71 1 187(1990年）特定言之係關於表面硬度之 程度，其係必要的俾能製造對於在重負荷應用中之使用係 足夠耐磨耗之齒輪。根據此專利，到達至少3go微米及至 多1，〇〇〇微米之深度之表面硬度或密實化作用 (densification)應係於全理論密度之9〇至1〇〇%之範圍内。 φ 未揭示關於製造方法之特定之細節但是陳述，由於混合之 粉末具有較可壓縮，致使於壓縮階段能到達較高之密度之 利益’因此混合之粉末係較佳的。此外，陳述，該混合之 粉末除了鐵及以重量計〇·2%之石墨以外，應包含分別以重 量計0.5%之鉬、鉻及錳。 與於美國專利5 711 187中敘述者相似之一種方法係於美 國專利5 54〇 883(1994年）中揭示。根據美國專利5 540 883 ’來自粉末金屬胚料之軸承表面係經由將碳與鐵合金 # 及/間滑劑與可壓縮之元素鐵粉末摻合、加壓該摻合之混合 物以生成粉末金屬胚料、於還原之大氣中高溫度燒結該胚 料壓縮違粉末金屬胚料以求製造具有軸承表面之經密實 化之層、然後熱處理該經密實化之層而製造。以重量百分 點片’經燒結之粉末金屬物件應具有〇.5至2 〇%鉻、〇至 1·0/〇鉬、0.1至06%碳，連同鐵及痕量雜質之餘數之組 成:述及關於壓縮壓力之寬廣之範圍。如此，陳述，壓縮 可係於25與50嘲每平方忖（約390-770百萬帕）之間之壓力進 行0 101192.doc 200539971 、、國專利5 552 1G9(1995年）係關於—種生成具有高密度 之U件之方法。該專利特定言之係關於連桿之製造。 如於美國專利5 71 1 187中，於美國專利$…⑽中未揭示 關L亥製造方法之特定之細節，但是陳述該粉末應係以預 。禱之鐵為主之粉末、該壓縮應係於單一步驟中進行、該 壓縮：力可於25與50噸每平方吋(390-770百萬帕)之間變動 以獲得於6 · 8與7 · 1 & /厘米3之間之m胚密度及該燒結應係 參於咼溫度進行，特定言之於1270與135(TC之間。陳述，獲 得具有高於7.4克/厘米3之密度之燒結產品及因此，高之燒 結密度係高溫度燒結之結果，係明顯的。 於美國專利5 729 822(1996年）中揭示，具有至少7·3克/ 厘米之核心密度及經硬化之經滲碳之表面之粉末金屬齒 輪。建議之粉末係相同於美國專利5 711 187及5 540 883中 者’即經由將碳、鐵合金及潤滑劑與元素鐵之可壓縮之粉 末摻合而獲得之混合物。為了獲得高之燒結核心密度，該 φ 專利述及溫加壓；二重加壓；二重燒結；高密度成形，如 於美國專利5 754 937中揭示；於粉末壓縮之期間模壁潤滑 之使用，以取代掺合之潤滑劑；及於燒結後之旋轉成形。 通常使用約40噸每平方吋（620百萬帕）之壓縮壓力。 經燒結之粉末冶金鋼之表面密實化作用係於例如the Technical Paper Series 820234, (International Congress & Exposition, Detroit，Michigan，February 22-26，1982)中討 論。於此論文中，報導燒結齒輪之表面輾軋之研究。對於 此研究，使用Fe-Cu-C及Ni-Mo合铸之材料。該論文顯示， 101192.doc 200539971 來自對於在6.6及7·1克/厘米3之密度之燒結零件之表面輾 軋之基礎研究之結果、及其對於燒結齒輪之應用。該等基 礎研究包含以不同直徑之輥子表面輾軋，以強度之方式表 示之最佳結果係以較小之輥子直徑、較低之厚度減少每通 過及大之總厚度減少而達成。作為Fe-Cu-C材料之實例， 90%之理論密度之密實化作用係以30毫米直徑之輥子至1.1 毫米之深度而達成。對於7·5毫米直徑輥子，相同程度之 密實化作用係至約〇·65毫米之深度而達成。然而，小直徑 輥能提高密實化作用至於表面之約全密度，而大直徑輥子 提高密度至於表面之約96%。表面輾軋技術係應用於經燒 結之油果齒輪及經燒結之曲軸齒輪。於Modern Developments in Powder Metallurgy，第 16冊，33-48 頁， 1984 年之一篇文章（來自 the International PM Conference June 17-22，1984，Toronto Canada，）中，作者已研究珠擊 法、碳氮共滲及其組合對於經燒結之Fe+1.5% Cii及Fe+2·% Cu+2.5% Ni合金之疲勞限界之效應。此等合金之報導之密 度係7.1及7.4克/厘米3。表面經輾軋之零件之表面輾軋方 法及彎曲疲勞試驗之理論評估皆係於Horizon of Powder Metallurgy part I，403-406 頁。Proceedings of the 1986 (International Powder Metallurgy Conference and Exhibition, Dusseldorf，7-11 July 1986)中之文章中發表。 根據先前技藝，已建議多種不同之途徑，俾能達到粉末 冶金組件之高之燒結密度。然而，該等建議之方法皆包含 添加另外費用之步驟。如此，溫壓縮及模壁潤滑促進高之 101192.doc 200539971 壓胚密度。由於高溫度燒結亦造成高之燒結密度之結果， 因此二重加壓及二重燒結造成高之燒結密度及收縮率。 此外，對於高負荷應用諸如齒輪，對於細孔尺寸及細孔 形怎必須考慮特別之預防措施，俾能達成足夠之疲勞性 質。用於製備具有高之燒結密度及機械強度（不論細孔尺 寸及形態）之齒輪及相似之產品，簡單並且成本有效之方 法因此將係吸引人的及本發明之主要目的。 【發明内容】 簡言之’現在已發現，於較苛求之應用（諸如動力傳送 應用）中之粉末金屬零件，例如，齒輪，可係經由將鐵或 以鐵為主之粉末於高於700百萬帕之壓力單軸向地壓縮至 高於7.35克/厘米3之密度、燒結該獲得之壓胚產物及將該 燒結產物經歷密實化作用方法而獲得。根據本發明之金屬 零件之核心之特性性質係細孔結構，其係以比較地大之細 孔而辨別。 特定地，本發明係關於一種燒結金屬零件（其具有經密 實化之表面及至少7.35(較佳地至少7.45)克/厘米3之核心密 度，其中該核心結構係經由以具有粗鐵或以鐵為主之粉末 粒子之以鐵為主之粉末混合物之單次加壓（不使用模壁潤 滑）至至少7.3 5克/厘米3(較佳地至少7.4 5克/厘米3)、及單次 燒結而獲得之細孔基質而辨別）、以及製造此等金屬零件 之方法。該細孔結構係經由使用根據ASTM E 1245之影像 分析提供相關於細孔尺寸之細孔面積分布而測量及評估。 以上之密度水準影響以純粹或低合鑄之鐵粉末為主之產 101192.doc -10- 200539971 品 粉末類型 屬 可使用作為壓縮方法之開始材料之適合金屬粉末係自八 諸如鐵製備之粉末。可將合鑄之元素諸如碳、絡、链、200539971 IX. INSTRUCTIONS OF THE INVENTION: TECHNICAL FIELD OF THE INVENTION The present invention relates to powder metal m. Specifically, the present invention relates to sintered metal parts having a densified surface and a system suitable for demanding applications. The invention also includes a method of making such metal parts. [Prior Art] There are several advantages to using a powder metallurgy method for manufacturing structural parts as compared with the conventional pairing method of full dense steel. As such, the energy consumption is very low and the material utilization is reported to be higher. Another important factor that favors the powder metallurgy approach is that components having a mesh shape or near mesh shape can be fabricated directly after the sintering process without the need for expensive forming such as turning, milling, boring or buffing. However, compared to powder metallurgy (pM) components, generally fully dense steel materials have superior mechanical properties. Therefore, efforts have been made to increase the density of powder metallurgical components to achieve values as close as possible to the density of fully dense steel. One of the future growth areas in the use of high-density powder metal parts is in the automotive industry. Of particular importance in this field are the use of powder metal parts in more demanding applications, such as power transmission applications, such as gears. The problem associated with gears generated via the powder metal process is that compared to gears made from strips or forgings, the powder metal gear has reduced bending fatigue strength in the root region of the gear and is low on the flank Contact fatigue strength. Such problems may be mitigated or even eliminated by the surface deformation of the root and the flank region by plastic deformation typically found by surface densification. A product that can be used in such demanding applications is described in, for example, U.S. Patent Nos. 5, 711, 187, 5, 540, 883, 5, 552, 109, 5, 729, 822, and 6, 171, 546. U.S. Patent 5,71, 187 (1990) teaches the extent of surface hardness, which is necessary to produce gears that are sufficiently wear resistant for use in heavy duty applications. According to this patent, the surface hardness or densification to a depth of at least 3 go micrometers and at most 1, 〇〇〇 micrometers should be in the range of 9 〇 to 1 〇〇% of the full theoretical density. φ does not disclose specific details regarding the manufacturing process but states that the mixed powder is preferred because the mixed powder is more compressible, resulting in a higher density in the compression stage. Further, it is stated that the mixed powder should contain 0.5% by weight of molybdenum, chromium and manganese, respectively, in addition to iron and 2% by weight of graphite. A method similar to that described in U.S. Patent No. 5,711,187 is incorporated herein by reference. According to US Pat. No. 5,540,883, the bearing surface from the powder metal blank is formed by mixing carbon and ferroalloy # and/or interslip agent with compressible elemental iron powder, and pressurizing the blended mixture to form a powder metal billet. The billet is sintered at a high temperature in a reduced atmosphere to compress the powder-free metal billet to produce a densified layer having a bearing surface, and then heat-treating the densified layer. In weight percent, the sintered powder metal material shall have a composition of 5.5 to 2 〇% chromium, 〇 to 1·0/〇 molybdenum, 0.1 to 06% carbon, together with the remainder of iron and trace impurities: A wide range of compression pressures. Thus, the statement, compression can be based on the pressure between 25 and 50 taunts per square inch (about 390-770 megapascals). 0 101192.doc 200539971, national patent 5 552 1G9 (1995) is about generation A method of having a high density U piece. This patent is specifically related to the manufacture of connecting rods. The specific details of the manufacturing method of the L Hai are not disclosed in U.S. Patent No. 5,71, 187, the disclosure of which is incorporated herein by reference. Pray iron-based powder, the compression should be carried out in a single step, the compression: the force can be varied between 25 and 50 tons per square inch (390-770 million Pa) to obtain 6 · 8 and 7 · m embryo density between 1 & /cm 3 and the sintering should be carried out at a temperature of 咼, specifically between 1270 and 135 (TC. It is stated that a density of more than 7.4 g/cm 3 is obtained. The sintered product and, therefore, the high sintered density is the result of high temperature sintering, which is evident in U.S. Patent 5,729,822 (1996), having a core density of at least 7.3 g/cm and a hardened permeate. A powder metal gear of the surface of the carbon. The proposed powder is the same as that obtained by blending carbon, an iron alloy and a lubricant with a compressible powder of elemental iron, in the same manner as in U.S. Patent Nos. 5,711,187 and 5,540,883. In order to obtain a high sintered core density, the φ patent describes warm pressurization; double pressurization; double sintering; high density forming, as disclosed in U.S. Patent 5,754,937; use of mold wall lubrication during powder compression To replace the blended lubricant; and after sintering Rotary forming. A compression pressure of about 40 tons per square inch (620 MPa) is usually used. The surface densification of sintered powder metallurgy steel is, for example, the Technical Paper Series 820234, (International Congress & Exposition, Detroit , Michigan, February 22-26, 1982). In this paper, the study of surface rolling of sintered gears is reported. For this study, Fe-Cu-C and Ni-Mo co-cast materials were used. , 101192.doc 200539971 Results from basic research on surface rolling of sintered parts at densities of 6.6 and 7.1 g/cm 3 and their application to sintered gears. These basic studies include rolls of different diameters. Surface rolling, the best result expressed in terms of strength is achieved with a smaller roll diameter, a lower thickness reduction per pass and a greater total thickness reduction. As an example of Fe-Cu-C material, 90% The densification of the theoretical density is achieved with a 30 mm diameter roller to a depth of 1.1 mm. For a 7.5 mm diameter roller, the same degree of compaction is about 〇·65 mm. The depth is achieved. However, the small diameter roller can increase the densification to about the full density of the surface, while the large diameter roller increases the density to about 96% of the surface. The surface rolling technique is applied to the sintered oily gear and Sintered crankshaft gear. In Modern Developments in Powder Metallurgy, Vol. 16, pp. 33-48, 1984, article (from the International PM Conference June 17-22, 1984, Toronto Canada,), the author has studied beads. The effect of the impact method, carbonitriding and its combination on the fatigue limit of the sintered Fe+1.5% Cii and Fe+2·% Cu+2.5% Ni alloy. The reported density of these alloys is 7.1 and 7.4 g/cm3. The theoretical evaluation of the surface rolling method and the bending fatigue test of the surface-rolled parts is based on Horizon of Powder Metallurgy part I, pages 403-406. Published in an article in Proceedings of the 1986 (International Powder Metallurgy Conference and Exhibition, Dusseldorf, 7-11 July 1986). According to the prior art, a number of different approaches have been proposed to achieve a high sintered density of powder metallurgical components. However, all of the suggested methods include the step of adding additional fees. Thus, warm compression and mold wall lubrication promote high density of 101192.doc 200539971. Since high temperature sintering also results in a high sintered density, double pressurization and double sintering result in high sintered density and shrinkage. In addition, for high-load applications such as gears, special precautions must be taken into account for the pore size and pore size, so that sufficient fatigue properties can be achieved. A simple and cost effective method for preparing gears and similar products having high sintered density and mechanical strength (regardless of pore size and morphology) would therefore be attractive and the primary object of the present invention. SUMMARY OF THE INVENTION In short, it has been found that powder metal parts, such as gears, in more demanding applications, such as power transfer applications, can be based on iron or iron-based powders above 700. The pressure of 10,000 Pa is uniaxially compressed to a density higher than 7.35 g/cm 3 , the obtained preformed product is sintered, and the sintered product is subjected to a densification method. The characteristic property of the core of the metal part according to the present invention is a fine pore structure which is discriminated by relatively large pores. In particular, the present invention relates to a sintered metal part having a densified surface and a core density of at least 7.35 (preferably at least 7.45) g/cm 3 , wherein the core structure is via to have coarse iron or iron Single pressurization of the iron-based powder mixture of the main powder particles (without mold wall lubrication) to at least 7.3 5 g/cm 3 (preferably at least 7.4 5 g/cm 3 ), and single sintering The fine pore matrix obtained is distinguished, and the method of manufacturing the metal parts. The pore structure was measured and evaluated by using the image analysis according to ASTM E 1245 to provide a pore area distribution related to the pore size. The above-mentioned density level affects the production of pure or low-cast iron powder. 101192.doc -10- 200539971 Product Powder type is a suitable metal powder that can be used as a starting material for the compression method. Can cast elements such as carbon, network, chain,
鉬、銅、鎳、磷、硫及其他如粒子、預合鑄或擴散合鑄加 入’俾能修飾最後之燒結產品之性質D該等以鐵為主之於 末可係由實質上純粹之鐵粉末、預合鑄之以鐵為主之: 子、擴散合鑄之以鐵為主之粒子、及鐵粒子或以鐵為主之 粒子與合鑄之元素之混合物組成之群中選出。至於粒子形 狀，該等粒子具有不規則之形式，如係經由水霧化而獲得 者，係較佳的。此外，具有不規則地成形之粒子之海綿鐵 粉末可係重要的。 至於用於高苛求之應用之粉末冶金零件，特別有希望之 結果已係以預合鑄之經水霧化之粉末獲得，該等粉末包含 低數量諸如至多5%之一種或多種之合鑄元素馗〇及〇。此 等粕末之實例係具有與來自H0ganas ΑΒ，之阿斯塔 羅伊合金（AStal〇y)Mo (1·5% M〇)及阿斯塔羅伊合金85 m〇 (〇·85 % Mo)以及阿斯塔羅伊合金(3% Cr、〇5% Μα) 及阿斯塔羅伊合金CrL(l 5% Cr、〇 2% Μ〇)之化學組成對 應之化學組成之粉末。 本發明之一種重要之性質係，使用之粉末具有粗粒子， 即粕末實質上無微細之粒子。術語"實質上無微細之粒子” 人十乂 ^表’低於約J 〇%(較佳地低於5%)之粉末粒子具 有低於45微米之尺寸，如經由於sS-En 24術中敛述之方 101192.doc -11 - 200539971 法而測量。平均粒子直徑通常係於75與则微米之間。大 於212微米之粒子之數量通常係高於2〇%。最大之粒子尺 寸可係約2毫米。 中之以鐵為主之粒子之尺寸係 通常使用於粉末冶金工業 根據高斯分布曲線分佈，具有於3G至⑽微米之區域中之 平均粒子直彳i及約HMG%之粒子料純㈣。因此，根Molybdenum, copper, nickel, phosphorus, sulfur and others such as particles, pre-cast or diffusion-casting are added to the properties of the final sintered product. These iron-based products can be substantially pure iron. Powder, pre-cast cast iron-based: sub-, diffusion-cast cast iron-based particles, and iron particles or iron-based particles and a mixture of elements of the casting selected. As for the particle shape, the particles have an irregular form, such as those obtained by water atomization, which is preferred. Further, sponge iron powder having irregularly shaped particles may be important. As regards powder metallurgical parts for highly demanding applications, particularly promising results have been obtained with pre-cast water-atomized powders containing low amounts of one or more of the casting elements, such as up to 5%馗〇 and 〇. Examples of such sputum are 85 M Mo (85·85 % Mo with Astaloy (Motorium) (A. 5% M〇) and Astaroy (85% Mo) from H0ganas ΑΒ And a chemical composition of the Astraloy (3% Cr, 〇 5% Μα) and Astarloy CrL (l 5% Cr, 〇 2% Μ〇) chemical composition of the chemical composition of the powder. An important property of the present invention is that the powder used has coarse particles, i.e., substantially fine particles at the end of the mash. The term "substantially no fine particles" is less than about J 〇% (preferably less than 5%) of powder particles having a size of less than 45 microns, as by sS-En 24 Measured by the method of 101192.doc -11 - 200539971. The average particle diameter is usually between 75 and then micron. The number of particles larger than 212 microns is usually higher than 2〇%. The largest particle size can be approximated. 2 mm. The size of the iron-based particles is usually used in the powder metallurgy industry according to the Gaussian distribution curve. The average particle diameter in the region of 3G to (10) micrometers and the particle purity of about HMG% (4) Therefore, the root
據本發明使用之粉末具有偏離通f使用者之粒子尺寸分 布。此等粉末可係經由移除粉末之較微細之部分或經由製 造具有需要之粒子尺寸分佈之粉末而獲得。 因此，對於以上提及之粉末，具有與阿斯塔羅伊合金“ M〇之化學組成對應之化學組成之粉末之適合粒子尺寸分 布可係最夕5%之粒子應係、小於45微米及平均粒子直徑通 常係於Π)6與_微米之間。具有對應於阿斯塔羅伊合金 CrL之化學組成之粉末之對應值適合地係，低於應係小 於45锨米及平均粒子直徑通常係於⑽與212微米之間。 根據本^明’為了獲得具有令人滿意之機械燒結性質之 、凡金屬零#，將石墨加入受壓縮之粉末混合物係必要 、曰匕可於壓縮之則，將石墨以受壓縮之總混合物之 重里计為0·1-1%，較佳地〇·2_1〇%，更佳地〇·2_〇·7%及最 0·5/〇之間之數$加人。然而，對於某些應用，石 墨添加不是必要的。 ;:、线為主之粉末轉移至模之前，亦可將其與潤滑劑 σ (内m滑）。潤滑劑係加人以於壓縮、或加壓步驟之 期間將於金屬粉末粒子之間及於粒子與模之間之摩擦減少 101192.doc 12 200539971 至最低。適合之潤滑劑之實例係，，硬脂酸醋、蠛、 脂肪酸及其衍生物、寡聚物、聚合物及其他具有潤滑效應 之有機物質。潤滑劑係以粒子之形式加入，但亦可黏附及 /或塗布於粒子。 較佳地，於粉末混合物中包含於w〇2〇〇4/〇37467中揭示 之類型之㈣化合物之潤滑塗料。特定地，該錢化合物 係烧基烧氧基或聚龍氧基錢，其巾㈣基絲基石夕烧 之烧基及豸聚驗貌氧基石夕燒之聚_包含於8個與3〇個之 間之碳原+，及炫氧基包含Μ個碳原子。此等化合物之 實例係辛基·三甲氧基㈣、十六基_三甲氧基我及具有 10個伸乙基醚（ethylene ether)基之聚伸乙基醚（p〇iy ethyleneether)-三甲氧基矽烷。 根據本發明，加入以鐵為主之粉末之潤滑劑之數量可於 該混合物之以重量計〇.〇5_·6%之間，較佳地於G 1〇5% 之間變動。 可將硬相、黏合劑、機械加工性增進劑及流動增進劑加 入，作為選用之添加劑。 壓縮 對於包含較微細之粒子、與低數量之潤滑劑（低於以重 量計0.6%)摻和之習用地使用之粉末，由於在高壓力(即， 高於600百萬帕之壓力)之習用之壓縮需要大力量俾能自模 驅出壓縮物、附隨之模之高磨耗及組件之表面趨於較不光 亮或劣化之事f，因此通常認為，於該等高壓力之習用之 壓縮不是適合的。經由使用根據本發明之粉末，已未預期 101192.doc 13 200539971 地發現，於高壓力之驅出力量係降低，及當不使用模壁潤 滑時亦可獲得具有可接受或甚至完美之表面之組件。 壓縮可係以標準之設備進行’其意表可進行新穎之方法 而不需要昂貴之投資。壓縮係於單—步驟中於周圍或提高 之溫度單軸向地進行^較佳地，壓縮壓力係高於約， 更佳地高於800及最佳地高於9〇0或甚至1〇〇〇百萬帕。為了 達到相關於本發明之利益，較佳地應進行壓縮至高於7 45 克/米3之密度。 燒結 可使用任何習用之燒結爐及燒結時間可於約15與6〇分鐘 之間變動。燒結爐之大氣可係吸熱型氣體大氣、於氫與氮 之間之混合物或於真空中。燒結溫度可於11〇〇與135〇^之 間變動。以高於約1250°C之燒結溫度，獲得最佳之結果。 於與包含二重加壓及二重燒結之方法比較中，根據本發明 之方法具有消除一個加壓步驟及一個燒結步驟而仍然可獲 得高於7.64克/厘米3之燒結密度之利益。 結構 面密度壓胚及燒結金屬零件之核心之辨別之性質係大細 孔之存在。因此，作為實例，於根據本發明之燒結金屬零 件之核心之剖面中，至少約5〇%之細孔面積係由具有至少 1〇〇微米2之細孔面積之細孔構成，而，於自對應之正常粉 末（即’包含正常數量之微細粒子之粉末，必須將其二重 加壓及二重燒結俾能達到相同之密度）製備之核心之剖面 中’至少約50〇/〇之細孔面積係由具有約65微米2之細孔面積 101192.doc -14- 200539971 之細孔構成。 表面密實化作用 表面雄貫化作用可係經由徑向或軸向之輾乾、珠擊法、 ' *及v、他而進行。由於徑向之輾乳提供短之循環時間連 同大之雄實化作用深度，因此較佳之方法係此種方法。具 1增加之密實化深度，粉末金屬零件將獲得較佳之機械性 夤咎實化作用深度較佳地係至少〇· 1毫米，更佳地至少 0·2毫米及最佳地至少〇·3毫米。 於本文之情況中應回想，通常認為於燒結零件中之大細The powder used in accordance with the present invention has a particle size distribution that deviates from the user of the pass. Such powders may be obtained by removing a relatively fine portion of the powder or by making a powder having a desired particle size distribution. Therefore, for the above-mentioned powder, the suitable particle size distribution of the powder having the chemical composition corresponding to the chemical composition of the Astaroy alloy "M〇 can be 5% of the particles, less than 45 microns and average The particle diameter is usually between Π6 and _micron. The corresponding value of the powder corresponding to the chemical composition of the Astarloy CrL is suitable for the system, less than 45 锨m and the average particle diameter is usually Between (10) and 212 microns. According to the present invention, in order to obtain a satisfactory mechanical sintering property, the addition of graphite to the compressed powder mixture is necessary, and if it is compressed, Graphite is from 0. 1% to 9%, preferably 〇 2% 〇%, more preferably 〇·2_〇·7% and most between 0. 5/〇, based on the total weight of the compressed mixture. Adding. However, for some applications, graphite addition is not necessary. ;: The line-based powder can also be added to the lubricant σ (internal m-slip) before it is transferred to the mold. During the compression or pressurization step, between the metal powder particles and between the particles and The friction between the reductions is 101192.doc 12 200539971 to the lowest. Examples of suitable lubricants are stearic acid vinegar, hydrazine, fatty acids and their derivatives, oligomers, polymers and other organic substances with lubricating effects. The lubricant is added in the form of particles, but may also be adhered and/or coated to the particles. Preferably, the lubricating coating of the compound of the type (IV) disclosed in the type disclosed in WO 2, 4/〇 37,467 is contained in the powder mixture. Specifically, the money compound is a burnt-base alkoxy group or a poly-l-oxyl group, and the towel (4) base-based base stone smoldering base and sputum-polymerized oxygen-stone smoldering _ are contained in 8 and 3 〇 Between the carbonogen +, and the methoxy group contains one carbon atom. Examples of such compounds are octyltrimethoxy (tetra), hexadecyl-trimethoxy, and 10 ethyl ether (ethylene ether) a polyethyl ether (p〇iy ethyleneether)-trimethoxydecane. According to the present invention, the amount of the lubricant added to the iron-based powder may be 5% by weight of the mixture. 〇5_·6 Between %, preferably between G 1 〇 5%. Hard phase, bonding , machinability improvers and flow improvers are added as optional additives. Compression for powders containing finer particles, blended with a lower amount of lubricant (less than 0.6% by weight), due to the use of Conventional compression at high pressures (ie, pressures above 600 MPa) requires a large amount of force to drive the compressed material out of the mold, the high wear of the attached mold, and the surface of the component tends to be less bright or deteriorated. F, therefore, it is generally believed that the compression of the conventional pressure is not suitable. By using the powder according to the present invention, it has been unexpectedly found that 101192.doc 13 200539971, the driving force at high pressure is reduced, and Components with acceptable or even perfect surfaces are also obtained when mold wall lubrication is not used. Compression can be done with standard equipment. It is intended to be a novel method without the need for expensive investments. Compression is carried out uniaxially in a single-step at ambient or elevated temperature. Preferably, the compression pressure is above about, more preferably above 800 and optimally above 9〇0 or even 1〇〇. 〇 million kPa. In order to achieve the benefits associated with the present invention, compression should preferably be carried out to a density above 7 45 g/m3. Sintering Any conventional sintering furnace can be used and the sintering time can vary between about 15 and 6 minutes. The atmosphere of the sintering furnace may be an endothermic gas atmosphere, a mixture of hydrogen and nitrogen or in a vacuum. The sintering temperature can vary between 11 〇 and 135 〇 ^. The best results are obtained at a sintering temperature above about 1250 °C. In comparison with the process comprising double pressurization and double sintering, the process according to the invention has the advantage of eliminating a pressurization step and a sintering step while still achieving a sintering density above 7.64 g/cm3. Structure The distinguishing nature of the surface density compactor and the core of the sintered metal part is the presence of large pores. Therefore, as an example, in the cross section of the core of the sintered metal part according to the present invention, at least about 5% of the pore area is composed of pores having a pore area of at least 1 μm 2 , and Corresponding normal powder (ie, a powder containing a normal amount of fine particles, which must be double-pressurized and double-sintered to achieve the same density), a core of at least about 50 Å/〇 in the core profile prepared. The area is composed of pores having a pore area of about 100 μm 2, 101192.doc -14 to 200539971. Surface Densification Surface ossification can be performed by radial or axial drying, beading, '* and v, and he. The preferred method is this method because the radial milk provides a short cycle time in conjunction with the depth of the large man. With an increased depth of densification, the powder metal part will preferably have a better mechanical tamping depth of at least 〇 1 mm, more preferably at least 0.2 mm and optimally at least 〇 3 mm . In the case of this article, it should be recalled that it is generally considered to be large in sintered parts.
孔之存在係缺點，及採取不同之措施俾能使細孔較小及較 ^ °然而，根據本發明，已令人驚舒地發現，比較地高數 2較大細孔之負面效應可係經由表面密實化作用方法而 70王地消除。因此，當將表面密實化作用對於在核心中含 車乂大細孔之燒結樣本之f曲纟勞強度之效應比較對於含較 小細孔之樣本之效應時，已發現，當樣本係自具有以上討 論之粒子尺寸分布之金屬粉末製造時，表面密實化作用方 曰力f曲疲勞強度至很較高之程度。於表面密實化作用 方法之後，自此等粉末製造之樣本之彎曲疲㈣度將令人 驚訝地達到與自具有正常之粒子尺寸分布之粉末製造之經 表面密實化之樣本相同之水準（假設相同之化學組成及相 同之燒結密度水準）。於是， 〇 ^ 、 由於向燒畤密度可係於單次 加壓、早次燒結方法中達到’因此對於例如齒輪之製造， 叩貝之方法（诸如二重加壓--舌威从 重燒結、溫壓縮）可係經由使 用根據本發明之方法而避免。 101192.doc 15 200539971 【實施方式】 本發明係經由下列之非限制之實例而進一步舉例說明。 使用下列以鐵為主之粉末； 粉末A， 阿斯塔羅伊合金85 Mo，具有0.80-0.95%之Mo含量、最 多0.02%之碳含量及最多0.20%之氧含量之經霧化之預合鑄 以鐵為主之粉末。 粉末A之粒子尺寸分佈係相似於通常使用於粉末冶金中 之粉末之粒子尺寸分佈；約0%大於250微米、約15-25%於 150與250微米之間及約15至30%小於45微米。 粉末B ; 相同於粉末A之化學組成但具有根據以下之表之較粗之 粒子尺寸分佈； 粒子尺寸微米 以重量計之％ >500 0 425-500 L9 300-425 20.6 212-300 27.2 150-212 20.2 106-150 13.8 75-106 6.2 45-75 5.9 <45 4.2The existence of the hole is a disadvantage, and different measures are taken to make the pores smaller and smaller. However, according to the present invention, it has been surprisingly found that the negative effect of the comparatively high number 2 large pores can be 70 kings are eliminated by the surface densification method. Therefore, when the surface densification effect is compared with the effect of the sample containing the smaller pores on the sintered sample containing the large pores of the rut in the core, it has been found that when the sample is In the manufacture of the metal powder of the particle size distribution discussed above, the surface densification has a very high degree of fatigue. After the surface densification method, the bending fatigue (four) degree of the sample made from such powders will surprisingly reach the same level as the surface-densified sample from the powder having a normal particle size distribution (assuming the same Chemical composition and the same level of sintering density). Thus, 〇^, because the density of the burning can be tied to a single pressurization, early sintering method to reach 'so for the manufacture of gears, for example, the method of mussels (such as double pressurization - tongue-and-shoulder from heavy sintering, warm Compression) can be avoided by using the method according to the invention. 101192.doc 15 200539971 [Embodiment] The present invention is further exemplified by the following non-limiting examples. The following iron-based powders are used; Powder A, Astaroy Alloy 85 Mo, atomized pre-combination with a Mo content of 0.80-0.95%, a carbon content of up to 0.02% and an oxygen content of up to 0.20% Cast iron-based powder. The particle size distribution of Powder A is similar to the particle size distribution of powders typically used in powder metallurgy; about 0% greater than 250 microns, about 15-25% between 150 and 250 microns, and about 15 to 30% less than 45 microns. . Powder B; Same as the chemical composition of Powder A but having a coarser particle size distribution according to the following table; Particle size Micron by weight % > 500 0 425-500 L9 300-425 20.6 212-300 27.2 150- 212 20.2 106-150 13.8 75-106 6.2 45-75 5.9 <45 4.2
粉末C ; 阿斯塔羅伊合金CrL，具有1.3 5-1.65%之Cr含量、0.1 ΤΟ·。？％之 Mo含量 、最多 0.010%之碳含量 及最多 0.25% 之氧 含量之經霧化之Mo-、Cr-預合鑄之以鐵為主之粉末。 粉末C之粒子尺寸分佈係相似於通常使用於粉末冶金中 101192.doc -16- 200539971 之粉末之粒子尺寸分佈；約0%大於25〇微米、約15_25%於 150與212微米之間及約μ至25%小於45微米。 粉末D ; 相同於粉末C之化學組成但具有根據以下之表之較粗之 粒子尺寸分佈； 粒子尺寸微米 以重量計之％ >500 ^ ~- 425-500 ~02 — ~~-- 300-425 ~Ta - ' 212-300 21.9 '~-- 150-212 '25.1 '~~--- 106-150 23.4 ' -- 75-106 n.z 45-75 " --- <45 ~3?7 —- 實例1 兩種混合物，混合物1A及1B係經由於壓縮之前徹底地 混合而製備。 混合物1A係以粉末A為主，具有以重量計〇2%之石墨及 以重量計0.8%之Η蠟之添加。 混合物1Β係以粉末Β為主，具有以重量計〇 2%之石墨及 以重量計0.2%之十六基三甲氧基石夕燒之添加。 將根據ISO 3928之FS-強度試驗棒壓縮。 以混合物1A為主之試驗棒係壓縮至71克/厘米3之壓胚密 度及於7 8 0 於9 0 %氮與丨〇 %氫之大氣中預燒結歷時3 〇分 鐘。於燒結之後，將樣本於1100百萬帕之壓力經歷第二次 壓縮及最後於mot於90%氮與1〇%氫之大氣中燒結歷時 30分鐘。測量燒結密度至7.61克/厘米3。 101192.doc -17- 200539971 自/吧合物1B製備之樣本係於單次壓縮方法中於〇〇百萬 帕壓縮及隨後係於128〇。(：於90。/。氮與1〇%氫之大氣中燒結 歷時30分鐘。燒結密度係7 67克/厘米3。 結果係於以下之表1中概述。 表1 混合物 1 Λ 粉末 壓力百萬帕/ 壓胚密度 燒結 °C 壓力 百萬帕 燒結 °c 燒結密度 克/厘米3 1Α 1 D FT斯塔羅伊合金85 0.80-0.95% Mo 標準0.2%石墨 7.1 780 1100 1280 7.61 ID 阿斯塔羅伊合金85 0.80-0.95% Mo 粗0.2%石墨 1100 1280 7.67 一半數目之獲得之燒結實體係經由於6巴空氣壓力以具 有0.4毫求直位之鋼球之珠擊法而經歷表面密實化作用方 法。 將經表面密實化之樣本及未經歷表面密實化作用方法之 樣本白於920 C於0.8%之碳勢（carb〇n p〇tencial)表面硬化歷 時75分鐘，接著於2〇〇°c回火操作歷時12〇分鐘。 對於所有之樣本，測定彎曲疲勞限界（BFL)。 圖1表示，對於經表面密實化之樣本及未經歷表面密實 化作用之樣本之彎曲疲勞限界。 自圖1可推論，相較於經由以具有習用粒度分佈之粉末 製造之樣本之表面密實化作用而獲得之彎曲疲勞限界增 加，以較粗之粉末製造之樣本之表面密實化作用促成於彎 曲疲勞限界中極大之增加。 圖2係顯示自混合物丨A製備之經表面密實化之樣本之剖 面之光學顯微鏡照片，及圖3係自混合物1B製備之經表面 101192.doc -18· 200539971 密實化之樣本之相似顯微鏡照片。 自樣本1A製造之經表面密實化樣本之剖面根據astm e 1245之影像分析顯示，約5〇%之總剖面孔面積係由具有η 微米或較大表面積之孔構成，而自混合物1Β製造之經表 面密實化樣本之相同測量顯示，約5〇%之總剖面面積係由 具有200微米2或較大表面積之孔構成。 實例2 經由於壓縮之前徹底地混合而製備兩種混合物，混合物 2C及 2D 〇 混合物2C係以粉末C為主，其添加〇.7重量％之鎳粉末、 0.2重量％之石墨及〇·8重量％之只蠛， 混合物2D係以粉末D為主，其添加〇·7%之鎳粉末、〇 2% 之石墨及0.2%之十六基三甲氧基矽烷。 製備根據ISO 392 8之FS-強度試驗棒。 以混合物2C為主之試驗棒係壓縮至71克/厘米3之壓胚密 參 度及於78〇°C於90%氮與1〇%氫之大氣中預燒結歷時3〇分 鐘。於燒結之後，將樣本於1100百萬帕之壓力經歷第二次 壓縮及最後於1280。(：於90%氮與1〇%氫之大氣中燒結歷時 30分鐘。測量燒結密度至7 63克/厘米3。 自此合物2D製備之試驗棒係於單次壓縮方法中以11 〇〇百 萬帕壓縮，接著於1280°C於90❶/〇氮與1〇。/。氫之大氣中燒結 歷時30分鐘。測量燒結密度至7 64克/厘米3。 結果係於以下之表3中概述。 表3 101192.doc 19 200539971 混合物 $末 . 壓力百萬帕/ 燒結 壓力 燒結 燒結密度 壓胚密度 °C 百萬帕 °c 克/厘米3 標準之CRL 1.35-1.65 %Cr 0.17-0.27% Mo + 0.7% Ni 7.1 780 1100 1280 7.63 2D 粗之CRL ~' 1.35-1.65% Cr 0.17-0.27% Mo + 0.7% Ni 1200— T64 一半數目之獲得之燒結實體係經由於6巴空氣壓力以具 有〇·4毫米直徑之鋼球之珠擊法而經歷表面密實化作用方 法0 將丄表面也實化之樣本及未經歷表面密實化作用方法之 樣本皆於920 C於0.8%之碳勢表面硬化歷時75分鐘，接著 於200 °c回火操作歷時120分鐘。 對於所有之樣本，測定彎曲疲勞限界（BFL)。 圖5表示’對於經表面密實化之樣本及未經歷表面密實 化作用之樣本之彎曲疲勞限界。 自圖5可推論’與經由以具有習用之粒子尺寸分佈之粉 _ 末製造之樣本之表面密實化作用而獲得之於彎曲疲勞限界 中之增加比較，以較粗之粉末製造之樣本之表面密實化作 用促成於彎曲疲勞限界中很較多之增加。 圖6係’顯不自混合物2C製備之經表面密實化之樣本之 4面之光學顯微鏡照片，及圖7係自混合物2D製備之經表 面密實化之樣本之相似之顯微鏡照片。 自樣本2C製造之經表面密實化之樣本之剖面之根據 STM E 1245之影像分析顯示，約5〇%之總剖面細孔面積 係由具有5〇微米2或較大之表面積之細孔構成，而自混合 10H92.doc -20. 200539971 物2D製造之經表面密實化之樣本之相同測量顯示，約“％ 之總剖面面積係由具有110微米2或較大之表面積之細孔構 成。 【圖式簡單說明】 圖1表不’於自根據實例1之混合物1A及1B製造之樣本 之表面密實化作用方法之前及之後之彎曲疲勞強度。 圖2係自混合物1A製備之經表面密實化之樣本之剖面之 光學顯微鏡照片。 圖3係自混合物1B製備之經表面密實化之樣本之剖面之 光學顯微鏡照片。 圖4表示’於自根據實例2之混合物2(：及21)製造之樣本 之表面密實化作用方法之前及之後之彎曲疲勞強度。 圖5係自混合物2C製備之經表面密實化之樣本之剖面之 光學顯微鏡照片。 圖6係自混合物2D製備之經表面密實化之樣本之剖面之 光學顯微鏡照片。 101192.doc -21 -Powder C; Astarloy CrL, with a Cr content of 1.3 5-1.65%, 0.1 ΤΟ·. ? % Mo content, up to 0.010% carbon content and up to 0.25% oxygen content of atomized Mo-, Cr-precast cast iron-based powder. The particle size distribution of Powder C is similar to the particle size distribution of powders commonly used in powder metallurgy 101192.doc -16-200539971; about 0% is greater than 25 microns, about 15-25% is between 150 and 212 microns, and about μ Up to 25% less than 45 microns. Powder D; the same as the chemical composition of powder C but with a coarser particle size distribution according to the following table; particle size micron by weight % >500 ^ ~- 425-500 ~02 - ~~-- 300- 425 ~Ta - ' 212-300 21.9 '~-- 150-212 '25.1 '~~--- 106-150 23.4 ' -- 75-106 nz 45-75 " --- <45 ~3?7 --- Example 1 Two mixtures, mixtures 1A and 1B were prepared by thorough mixing prior to compression. The mixture 1A was mainly powder A, and had an addition of 2% by weight of graphite and 0.8% by weight of wax. The mixture 1 is mainly powdered bismuth, and has an addition of 2% by weight of graphite and 0.2% by weight of hexadecyltrimethoxy sulphate. The FS-strength test rod according to ISO 3928 will be compressed. The test rods based on the mixture 1A were compressed to a density of 71 g/cm 3 and pre-sintered in an atmosphere of 780 at 90% nitrogen and 丨〇 % hydrogen for 3 〇 minutes. After sintering, the sample was subjected to a second compression at a pressure of 1100 MPa and finally sintered in an atmosphere of 90% nitrogen and 1% hydrogen for 30 minutes. The sintered density was measured to 7.61 g/cm3. 101192.doc -17- 200539971 The sample prepared from the bar complex 1B was compressed in 单 million kPa in a single compression process and subsequently tied at 128 Torr. (: Sintering in an atmosphere of 90% nitrogen and 1% hydrogen for 30 minutes. The sintered density is 7 67 g/cm3. The results are summarized in Table 1 below. Table 1 Mixture 1 Λ Powder pressure million Pa / Embedding Density Sintering °C Pressure Million Pa Sintering °c Sintering Density g/cm 3 1Α 1 D FT Staroy Alloy 85 0.80-0.95% Mo Standard 0.2% Graphite 7.1 780 1100 1280 7.61 ID Astaro I-alloy 85 0.80-0.95% Mo coarse 0.2% graphite 1100 1280 7.67 Half of the obtained sintered solid system undergoes surface densification by a ball striking method with a steel ball of 0.4 milli-straight position at 6 bar air pressure The surface-densified sample and the sample that has not undergone the surface densification method are white hardened at 920 C on a carbon potential of 0.8% (carb〇np〇tencial) for 75 minutes, followed by tempering at 2 ° °c. The operation lasted for 12 minutes. For all samples, the bending fatigue limit (BFL) was determined. Figure 1 shows the bending fatigue limit for samples that have been surface-densified and those that have not undergone surface densification. Compared with The bending fatigue limit obtained by the surface densification of the sample made of the powder of the particle size distribution is increased, and the surface densification of the sample made of the coarser powder contributes to a great increase in the bending fatigue limit. Fig. 2 shows the self-mixing An optical micrograph of a section of a surface-densified sample prepared by 丨A, and FIG. 3 is a similar micrograph of a sample prepared from the mixture 1B through a surface of 101192.doc -18· 200539971. The profile of the surface-densified sample according to the image analysis of astm e 1245 shows that about 5% of the total cross-sectional pore area is composed of pores having η micrometers or larger surface area, and the surface-densified samples manufactured from the mixture 1Β are the same. Measurements showed that about 5% of the total cross-sectional area consisted of pores having a surface area of 200 μm 2 or larger. Example 2 Two mixtures were prepared by thorough mixing before compression, and the mixture 2C and 2D 〇 mixture 2C was powdered. C is mainly composed of 7% by weight of nickel powder, 0.2% by weight of graphite and 〇·8% by weight of ruthenium, and the mixture 2D is Powder D is mainly composed of 7%·7% of nickel powder, 〇2% of graphite and 0.2% of hexadecyltrimethoxydecane. Preparation of FS-strength test rod according to ISO 392 8. Based on mixture 2C The test rods were compressed to a compact density of 71 g/cm 3 and pre-sintered at 78 ° C in an atmosphere of 90% nitrogen and 1% hydrogen for 3 minutes. After sintering, the samples were taken at 1100 The pressure of Wanpa experienced a second compression and finally at 1280. (: Sintering in an atmosphere of 90% nitrogen and 1% hydrogen for 30 minutes. The sintered density was measured to 7 63 g/cm 3. The test rod prepared from this compound 2D was in a single compression method at 11 〇〇 Millions of Pa compression, followed by sintering at 90 ° C / 〇 Nitrogen and 1 Torr at 1280 ° C for 30 minutes in a hydrogen atmosphere. The sintered density was measured to 7 64 g / cm 3 . The results are summarized in Table 3 below Table 3 101192.doc 19 200539971 Mixture $. Pressure MPa / Sintering Pressure Sintering Sintered Density Density °C Million Pa °c g/cm 3 Standard CRL 1.35-1.65 %Cr 0.17-0.27% Mo + 0.7% Ni 7.1 780 1100 1280 7.63 2D Crude CRL ~' 1.35-1.65% Cr 0.17-0.27% Mo + 0.7% Ni 1200- T64 Half of the obtained sintered solid system has a 〇·4 via 6 bar air pressure The millimeter-diameter steel ball is subjected to the surface densification method. The sample which has also stabilized the surface of the crucible and the sample which has not undergone the surface densification method are hardened at 920 C for a carbon potential of 0.8% for 75 minutes. Then temper at 200 °c for 120 minutes. For all samples, The bending fatigue limit (BFL) is determined. Figure 5 shows the bending fatigue limit for a sample that has been surface-densified and that has not undergone surface densification. Figure 5 can be inferred from the powder with a conventional particle size distribution. _ The comparison of the surface densification of the last manufactured sample to the increase in the bending fatigue limit, the surface densification of the sample made with the coarser powder promotes a large increase in the bending fatigue limit. 'Photomicrographs of the four sides of the surface-densified sample prepared from the mixture 2C, and Figure 7 are similar micrographs of the surface-densified sample prepared from the mixture 2D. Surfaces manufactured from the sample 2C Image analysis of the densified sample according to STM E 1245 shows that about 5% of the total cross-sectional pore area is composed of pores having a surface area of 5 μm 2 or larger, and self-mixing 10H92.doc - 20. 200539971 The same measurement of a surface-densified sample made by 2D shows that about 5% of the total cross-sectional area is made up of pores with a surface area of 110 μm 2 or larger BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows the bending fatigue strength before and after the surface densification method of the samples prepared from the mixtures 1A and 1B of Example 1. Fig. 2 is a surface prepared from the mixture 1A. An optical micrograph of a section of a densified sample. Figure 3 is an optical micrograph of a section of a surface-densified sample prepared from Mix 1B. Fig. 4 shows the bending fatigue strength before and after the surface densification method of the sample produced from the mixture 2 (: and 21) according to Example 2. Figure 5 is an optical micrograph of a section of a surface-densified sample prepared from Mix 2C. Figure 6 is an optical micrograph of a section of a surface-densified sample prepared from a mixture 2D. 101192.doc -21 -