JP2005082825A - Chromium carbide layer-containing cemented carbide - Google Patents
Chromium carbide layer-containing cemented carbide Download PDFInfo
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本発明は、おもに金属などの切削加工に使用される超硬合金および被覆超硬合金の基材として使用される超硬合金に関する。 The present invention relates to a cemented carbide used mainly as a base material for cemented carbide and coated cemented carbide used for cutting of metals and the like.
超硬合金にクロムを添加すると、強度，靱性，耐熱性，耐酸化性，耐食性など多くの特性が改善され、耐摩耗性，耐チッピング性，耐溶着性などの切削性能も向上することが知られている。 It is known that adding chromium to cemented carbide improves many properties such as strength, toughness, heat resistance, oxidation resistance and corrosion resistance, and also improves cutting performance such as wear resistance, chipping resistance and welding resistance. It has been.
クロムを含有した切削用超硬合金の従来技術として、Ｃｒが金属結合相量に対して５〜３５重量％含有され、該結合相量が合金の４〜２５重量％を占め、残部が平均粒子径１〜１０μｍのＷＣで構成されたアルミ加工用超硬がある（例えば、特許文献１参照。）。また、３〜２５重量％のＣｏおよびＮｉの総量と、ＣｏおよびＮｉに対してＣｒを炭化クロム換算で１０〜３０重量％含み、残部が炭化タングステンおよび不可避不純物からなる超硬合金とその被覆超硬合金がある（例えば、特許文献２参照。）。 As a prior art of a cemented carbide for cutting containing chromium, Cr is contained in an amount of 5 to 35% by weight based on the amount of metal binder phase, the amount of the binder phase accounts for 4 to 25% by weight of the alloy, and the balance is an average particle There is a cemented carbide for aluminum processing composed of WC having a diameter of 1 to 10 μm (for example, see Patent Document 1). Further, a cemented carbide containing 3 to 25% by weight of Co and Ni, 10 to 30% by weight of Cr in terms of chromium carbide with respect to Co and Ni, and the balance of tungsten carbide and inevitable impurities, and its coated super There are hard alloys (for example, see Patent Document 2).
これらのクロム含有超硬合金は、切削工具に使用する場合に最適なＣｒ含有量およびＣｏ／Ｎｉ比，ＷＣ粒度を限定したものではあるが、添加された炭化クロム量が少なく、また表面近傍に析出していないために、その効果が十分に発揮されていない。 Although these chromium-containing cemented carbides are limited in Cr content, Co / Ni ratio, and WC grain size, which are optimal for use in cutting tools, the amount of added chromium carbide is small and near the surface. Since it does not precipitate, the effect is not fully exhibited.
本発明は、上記のような問題点を解決するもので、具体的には、添加された炭化クロム結晶を超硬合金の表面に薄片状に析出させることにより、強固な密着性を確保した上で、耐摩耗性，耐溶着性，耐焼付き性などの実用性能を大幅に向上させた炭化クロム層を有する超硬合金の提供を目的とする。 The present invention solves the above-described problems. Specifically, the added chromium carbide crystal is deposited in the form of flakes on the surface of the cemented carbide to ensure strong adhesion. Therefore, an object of the present invention is to provide a cemented carbide having a chromium carbide layer with substantially improved practical performance such as wear resistance, welding resistance, and seizure resistance.
本発明者は、長年に亘りクロム添加超硬合金の更なる性能向上について検討していた所、炭化クロム量と炭素量を多めに調整した混合粉末を焼結すると合金表面に炭化クロム層を形成させることができ性能が向上するという知見を得て本発明を完成するに至ったものである。 The present inventor has been studying further improvements in the performance of chromium-added cemented carbide for many years, and forms a chromium carbide layer on the alloy surface when sintering a mixed powder with a larger amount of chromium carbide and carbon. The present invention has been completed with the knowledge that the performance can be improved.
すなわち、本発明の炭化クロム層を有する超硬合金は、２〜２０重量％の鉄族金属と、鉄族金属に対してクロムをＣｒ3Ｃ2換算で３０〜１５０重量％とを含み、残りが炭化タングステンを主成分とする硬質相からなる超硬合金において、該超硬合金表面の少なくとも一部に平均厚み０．１〜１０μｍの炭化クロム層を有する超硬合金である。 That is, the cemented carbide having the chromium carbide layer of the present invention contains 2 to 20% by weight of an iron group metal and 30 to 150% by weight of chromium in terms of Cr 3 C 2 with respect to the iron group metal, and the rest. Is a cemented carbide having a chromium carbide layer having an average thickness of 0.1 to 10 μm on at least a part of the surface of the cemented carbide.
本発明の超硬合金における鉄族金属は、Ｃｏ，Ｎｉ，Ｆｅの中の少なくとも１種であり、１５重量％以下のＣｒと２０重量％以下のＷとを固溶して合金化し結合相を形成しているものである。結合相として具体的には、Ｃｏ−Ｃｒ合金，Ｎｉ−Ｃｒ−Ｗ合金，Ｃｏ−Ｎｉ−Ｃｒ−Ｗ合金，Ｆｅ−Ｎｉ−Ｃｒ合金，Ｆｅ−Ｎｉ−Ｍｏ−Ｃｒ合金などを挙げることができる。 The iron group metal in the cemented carbide of the present invention is at least one of Co, Ni, and Fe, and 15 wt% or less of Cr and 20 wt% or less of W are dissolved to form an alloy and form a binder phase. It is what is formed. Specific examples of the binder phase include a Co—Cr alloy, a Ni—Cr—W alloy, a Co—Ni—Cr—W alloy, a Fe—Ni—Cr alloy, and a Fe—Ni—Mo—Cr alloy. .
本発明の超硬合金において結合相を形成する鉄族金属は、２重量％未満では合金内に巣孔が残留するために硬さ，強度，靱性および耐欠損性が低下すると共に結合相量が少ないために炭化クロム層を形成し難く、逆に２０重量％を超えて多くなると硬さや耐摩耗性性が低下するために２〜２０重量％と定めた。 In the cemented carbide alloy of the present invention, the iron group metal forming the binder phase is less than 2% by weight, so that voids remain in the alloy, resulting in a decrease in hardness, strength, toughness and fracture resistance, and the amount of binder phase. It is difficult to form a chromium carbide layer due to the small amount, and conversely, if it exceeds 20% by weight, the hardness and wear resistance deteriorate, so the content was determined to be 2 to 20% by weight.
本発明の超硬合金における炭化クロムは、具体的には、主に少量の鉄族金属を固溶したＣｒ7Ｃ3であるが、Ｃｒ3Ｃ2，Ｃｒ23Ｃ6、Ｃｒ7Ｃ3−Ｆｅ3Ｃ系化合物なども挙げることができる。合金内部において炭化クロムは金属結合相中あるいは炭化タングステンの粒子間に微細な粒子状になって分散し、合金表面において炭化クロムは合金表面に対して平行に粒成長した薄片状結晶となり合金表面の一部または全体を覆っている。図１には本発明超硬合金の表面組織の一例を示す。濃い灰色の薄片状部分が炭化クロム層を示し、薄い灰色部分は炭化クロム層が析出していない合金表面を示している。合金表面に析出した炭化クロム層は、平均厚みが０．１〜１０μｍ、長さが１０〜１０００μｍ、幅が２〜５００μｍの薄片状結晶をなす。炭化クロム量，鉄族金属量，炭素量などを適切に選定すると、炭化クロム層によって合金表面全体を被覆することができる。 Specifically, the chromium carbide in the cemented carbide of the present invention is mainly Cr 7 C 3 in which a small amount of iron group metal is dissolved, but Cr 3 C 2 , Cr 23 C 6 , Cr 7 C 3 − Examples thereof include Fe 3 C-based compounds. In the alloy, chromium carbide is dispersed in the form of fine particles in the metallic binder phase or between the tungsten carbide particles. On the alloy surface, the chromium carbide becomes flaky crystals grown in parallel to the alloy surface. Covers part or the whole. FIG. 1 shows an example of the surface structure of the cemented carbide of the present invention. The dark gray flaky portion indicates the chromium carbide layer, and the light gray portion indicates the alloy surface on which the chromium carbide layer is not deposited. The chromium carbide layer deposited on the alloy surface forms flaky crystals having an average thickness of 0.1 to 10 μm, a length of 10 to 1000 μm, and a width of 2 to 500 μm. If the chromium carbide content, iron group metal content, carbon content, etc. are appropriately selected, the entire alloy surface can be covered with the chromium carbide layer.
本発明の超硬合金のクロム含有量は、鉄族金属量に対してＣｒ3Ｃ2換算で３０重量％未満では合金表面に炭化クロム層が形成されない、もしくは形成されても被覆面積割合が少ない。そのために、炭化クロム層による耐摩耗性，耐溶着性，耐焼付き性の改善効果が少ない。逆に１５０重量％を超えて大きくなると合金の強度が急激に低下するため、３０〜１５０重量％と定めた。 When the chromium content of the cemented carbide of the present invention is less than 30% by weight in terms of Cr 3 C 2 with respect to the amount of iron group metal, a chromium carbide layer is not formed on the alloy surface, or even if formed, the coated area ratio is small. . For this reason, the effect of improving the wear resistance, welding resistance, and seizure resistance by the chromium carbide layer is small. On the other hand, when the content exceeds 150% by weight, the strength of the alloy is abruptly decreased.
本発明の超硬合金において、炭化タングステンを主成分とする硬質相は、炭化タングステンあるいは炭化タングステンと周期律表４ａ，５ａ，６ａ族金属の炭化物，窒化物およびこれらの相互固溶体の中の少なくとも１種からなる立方晶化合物とで構成され硬質相全体の５０重量％以上が炭化タングステンからなる硬質相である。ここで、炭化タングステンとして具体的にはＷＣを挙げることができる。また、立方晶化合物として具体的にはＶＣ，ＴａＣ，ＮｂＣ，ＴｉＮ，ＨｆＮ，（Ｗ，Ｔｉ）Ｃ，（Ｗ．Ｔｉ．Ｔａ）Ｃ，（Ｗ，Ｔｉ，Ｔａ）（Ｃ，Ｎ），（Ｗ，Ｚｒ）（Ｃ．０），（Ｔｉ，Ｗ，Ｃｒ）Ｃ，（Ｔｉ，Ｗ，Ｍｏ）（Ｃ，Ｎ）などを挙げることができる。 In the cemented carbide of the present invention, the hard phase mainly composed of tungsten carbide is at least one of tungsten carbide or tungsten carbide and carbides, nitrides of Group 4a, 5a, and 6a metals of the periodic table, and mutual solid solutions thereof. The hard phase is composed of a cubic compound composed of seeds and 50% by weight or more of the entire hard phase is composed of tungsten carbide. Here, specific examples of tungsten carbide include WC. Specific examples of cubic compounds include VC, TaC, NbC, TiN, HfN, (W, Ti) C, (W. Ti. Ta) C, (W, Ti, Ta) (C, N), ( W, Zr) (C.0), (Ti, W, Cr) C, (Ti, W, Mo) (C, N), and the like.
本発明の超硬合金における炭化クロム層は、平均厚みが０．１〜１０μｍでなるものである。ここで炭化クロム層の平均厚みは炭化クロム層で覆われた部分のみの平均値とした。炭化クロム層の平均厚みは、０．１μｍ未満では耐摩耗性，耐溶着性，耐焼付き性，被覆膜との密着性の改善効果が少なく、逆に１０μｍを超えて大きくなる炭化クロム層の結晶内で脆性破壊が起こり欠けやチッピングを生じ易い。そのため０．１〜１０μｍと定めた。また合金表面全体に対する炭化クロム層の被覆面積の割合が３０面積％未満では炭化クロム層による耐摩耗性，耐溶着性，耐焼付き性の改善効果が少ない。したがって３０面積％以上が好ましい。 The chromium carbide layer in the cemented carbide of the present invention has an average thickness of 0.1 to 10 μm. Here, the average thickness of the chromium carbide layer was the average value of only the portion covered with the chromium carbide layer. If the average thickness of the chromium carbide layer is less than 0.1 μm, the effect of improving the wear resistance, welding resistance, seizure resistance, and adhesion to the coating film is small. Brittle fracture occurs within the crystal and chipping or chipping is likely to occur. Therefore, it was determined as 0.1 to 10 μm. If the ratio of the coated area of the chromium carbide layer to the entire alloy surface is less than 30% by area, the effect of improving the wear resistance, welding resistance and seizure resistance by the chromium carbide layer is small. Therefore, 30 area% or more is preferable.
本発明の超硬合金の表面組成は、炭化クロム層に覆われた部分を除くと内部組成と同一になる場合が多いが結合相や遊離炭素で覆われる場合もある。結合相が合金表面に層状に存在すると耐摩耗性や耐溶着性が低下するが、遊離炭素の薄い層が合金表面に存在すると耐溶着性がさらに改善されるので好ましい。 The surface composition of the cemented carbide of the present invention is often the same as the internal composition except for the portion covered with the chromium carbide layer, but may be covered with a binder phase or free carbon. When the binder phase is present in layers on the alloy surface, the wear resistance and welding resistance are lowered. However, it is preferable that a thin layer of free carbon is present on the alloy surface because the welding resistance is further improved.
本発明の超硬合金の製造方法については、炭化クロム量と炭素量を多めに調整した混合粉末を焼結すると合金表面に炭化クロム層を形成することができる。具体的には、焼結後に若干の遊離炭素が析出する程度に高炭素合金となるように炭素量を配合し、原料粉末混合、加圧成形、非酸化性雰囲気での焼結の各工程を経て製造できる。従って、本発明の超硬合金は合金内部に０．５体積％以下の遊離炭素を含有すると、炭化クロム層の形成が容易となるので好ましい。逆に、０．５体積％を超えて大きくなると焼結温度において遊離炭素が残留するため炭化クロム層の形成が困難となる。また遊離炭素を含有しない合金でも、焼結時に浸炭雰囲気（例えば、少量のＣＯ，ＣＨ4ガスを導入）とすることによって、合金表面に炭化クロム層を析出させることが可能となる。以上の通り炭化クロム層の形成に炭素量は大きな影響を及ぼす。なお、薄片状結晶の炭化クロム層は、焼結時の金属液相に溶解した炭化クロムが合金表面に析出すると考えられる。 With respect to the method for producing a cemented carbide according to the present invention, a chromium carbide layer can be formed on the alloy surface by sintering a mixed powder in which the amount of chromium carbide and the amount of carbon are adjusted to be large. Specifically, the amount of carbon is blended so that it becomes a high carbon alloy to the extent that some free carbon precipitates after sintering, and each step of raw material mixing, pressure forming, and sintering in a non-oxidizing atmosphere is performed. It can be manufactured after that. Therefore, it is preferable that the cemented carbide of the present invention contains 0.5% by volume or less of free carbon in the alloy because the chromium carbide layer can be easily formed. Conversely, if it exceeds 0.5% by volume, free carbon remains at the sintering temperature, making it difficult to form a chromium carbide layer. Even in an alloy that does not contain free carbon, a chromium carbide layer can be deposited on the alloy surface by setting a carburizing atmosphere (for example, introducing a small amount of CO, CH 4 gas) during sintering. As described above, the amount of carbon greatly affects the formation of the chromium carbide layer. In the flaky crystalline chromium carbide layer, it is considered that chromium carbide dissolved in the metal liquid phase during sintering precipitates on the alloy surface.
本発明の超硬合金における炭化クロム層の面積や厚みの制御は、組成調整する以外の方法でも行うことができる。例えば、被覆面積と厚みの両方を大きくするには、焼結後に金属液相が存在する１２００〜１２５０℃で浸炭雰囲気にして保持すれば良く、被覆面積を大きくして炭化クロム層の厚みを薄くするには、合金表面焼肌面を研削除去した後、再度加熱して同様の処理を行えば良い。 Control of the area and thickness of the chromium carbide layer in the cemented carbide of the present invention can be performed by methods other than adjusting the composition. For example, in order to increase both the coating area and the thickness, it is only necessary to maintain a carburizing atmosphere at 1200 to 1250 ° C. in which a metal liquid phase exists after sintering, and to increase the coating area and reduce the thickness of the chromium carbide layer. For this purpose, the surface of the alloy surface is removed by grinding and then heated again to perform the same treatment.
本発明の超硬合金の用途の一つとしては、アルミニウム，銅，耐熱合金などの非鉄金属の切削工具を挙げることができる。また、用途の一つとしては、鋼，鋳物の切削加工に使用される被覆超硬合金の基材を挙げることができる。本発明の超硬合金にＣＶＤ法またはＰＶＤ法によって被膜を被覆すると、炭化クロム層から被膜へクロムが拡散し、被膜の密着性が改善される。 One of the uses of the cemented carbide of the present invention is a cutting tool made of non-ferrous metals such as aluminum, copper and heat-resistant alloys. Moreover, as one of the uses, the base material of the coated cemented carbide used for the cutting process of steel and a casting can be mentioned. When the cemented carbide of the present invention is coated with a CVD method or PVD method, chromium diffuses from the chromium carbide layer to the coating, and the adhesion of the coating is improved.
本発明の超硬合金は、炭化クロム量，鉄族金属量，炭素量などを適切に選定した合金組成が表面に炭化クロム層を形成させる作用をし、形成された炭化クロム層が耐摩耗性，耐溶着性，耐焼付き性を向上する作用をする。被覆超硬合金の基材に用いた場合には、被膜中へのクロムの拡散が被膜の密着性を改善する作用をしているものである。 In the cemented carbide of the present invention, the alloy composition in which the amount of chromium carbide, the amount of iron group metal, the amount of carbon, etc. are appropriately selected acts to form a chromium carbide layer on the surface, and the formed chromium carbide layer is wear resistant. , Acts to improve welding resistance and seizure resistance. When used as a coated cemented carbide substrate, the diffusion of chromium into the coating serves to improve the adhesion of the coating.
本発明の炭化クロム層を有する超硬合金は、表面に炭化クロム層を有しない従来の超硬合金に比べて、耐溶着性，耐焼付き性，被膜との密着性に優れるため、例えば、アルミニウム切削では摩耗が少なく仕上げ面も美麗であり、被覆超硬合金による鋼切削では膜剥離によるチッピング摩耗を生じ難いために長寿命であるという効果がある。 The cemented carbide having a chromium carbide layer of the present invention is superior in welding resistance, seizure resistance, and adhesion to a coating compared to a conventional cemented carbide having no chromium carbide layer on its surface. There is little wear in cutting and the finished surface is beautiful, and steel cutting with coated cemented carbide has the effect of long life because chipping wear due to film peeling hardly occurs.
市販されている平均粒子径が０．５μｍのＷＣ（ＷＣ／Ｆと記す），１．５μｍのＷＣ（ＷＣ／Ｍと記す），４．５μｍのＷＣ（ＷＣ／Ｃと記す），０．０２μｍのカーボンブラック（Ｃと記す），１．１μｍのＣｒ3Ｃ2，１．０μｍのＣｏ，１．２μｍのＮｉ，１．２μｍのＦｅ，２．１μｍのＶＣ，１．０μｍのＴａＣ，１．２μｍの（Ｗ，Ｔｉ，Ｔａ）Ｃ（重量比でＷＣ／ＴｉＣ／ＴａＣ＝５０／２０／３０），１．５μｍのＴｉＮの各粉末を用い、表１に示した配合組成に秤量して、ステンレス製ポットにアセトン溶媒と超硬合金製ボールとともに挿入し、４８時間混合粉砕後、乾燥して混合粉末を得た。ここで、配合炭素量は焼結後の合金中に若干の遊離炭素が析出する、または、遊離炭素が析出しなくても高炭素合金となるように調整した。また、各混合粉末での鉄族金属量に対するＣｒ3Ｃ2量を表１に併記した。 WC having a mean particle size of 0.5 μm (denoted as WC / F), 1.5 μm WC (denoted as WC / M), 4.5 μm WC (denoted as WC / C), 0.02 μm Carbon black (denoted as C), 1.1 μm Cr 3 C 2 , 1.0 μm Co, 1.2 μm Ni, 1.2 μm Fe, 2.1 μm VC, 1.0 μm TaC, Using each powder of 2 μm (W, Ti, Ta) C (weight ratio WC / TiC / TaC = 50/20/30) and 1.5 μm TiN, weighed to the composition shown in Table 1, The mixture was inserted into a stainless steel pot together with an acetone solvent and a cemented carbide ball, mixed and ground for 48 hours, and dried to obtain a mixed powder. Here, the amount of blended carbon was adjusted so that some free carbon was precipitated in the sintered alloy, or a high carbon alloy was formed even if no free carbon was precipitated. Table 1 also shows the amount of Cr 3 C 2 with respect to the amount of iron group metal in each mixed powder.
そして、これらの混合粉末をＩＳＯ規格でＳＮＭＧ１２０４０８のハイレーキブレーカ付きチップの金型に充填し、１９６ＭＰａの圧力でもって圧粉成形体とした後、アルミナとカーボン繊維からなるシート上に設置して真空焼結炉に挿入し、雰囲気圧力が１０Ｐａの真空中で、表１に併記した焼結温度でもって１時間加熱・保持して、本発明品１〜１1及び比較品１〜９の超硬合金製チップを得た。但し、本発明品３と４では、焼結後の冷却中に浸炭処理（３００ＰａのＣＯガスを導入し、１２５０℃に３０分保持）を施した。 Then, these mixed powders are filled in a die of a chip with a high rake breaker of SNMG120408 according to the ISO standard, made into a green compact with a pressure of 196 MPa, and then placed on a sheet made of alumina and carbon fiber and vacuumed. Inserted into a sintering furnace, heated and held for 1 hour at the sintering temperature listed in Table 1 in a vacuum with an atmospheric pressure of 10 Pa, cemented carbides of the present invention products 1-11 and comparative products 1-9 A chip made was obtained. However, in the products 3 and 4 of the present invention, carburizing treatment (300 Pa CO gas was introduced and held at 1250 ° C. for 30 minutes) was performed after cooling after sintering.
こうして得られた超硬チップの焼肌面を電子顕微鏡で観察して組織写真を撮り、炭化クロム結晶層で覆われている部分の面積割合を画像処理装置により求めた。次に、超硬チップを切断し、切断面を＃２３０のダイヤモンド砥石で湿式研削加工した後、１μｍのダイヤモンドペーストでラップ加工して表面および内部組織の断面観察用試料を得た。そして、電子顕微鏡で観察して表面近傍の組織写真を撮り、合金表面に形成された炭化クロム層の平均厚みを測定した。これらの測定結果を表２に示す。 The burned surface of the cemented carbide chip thus obtained was observed with an electron microscope, a structure photograph was taken, and the area ratio of the portion covered with the chromium carbide crystal layer was determined by an image processing apparatus. Next, the cemented carbide chip was cut, and the cut surface was wet ground with a # 230 diamond grindstone, and then lapped with a 1 μm diamond paste to obtain a sample for observing the cross section of the surface and internal structure. And it observed with the electron microscope, the structure | tissue photograph of the surface vicinity was taken, and the average thickness of the chromium carbide layer formed in the alloy surface was measured. These measurement results are shown in Table 2.
さらに、断面観察用試料の内部を観察して組織写真を撮り、画像処理装置を使用してＷＣ，金属結合相，炭化クロム相（主にＣｒ7Ｃ3），遊離炭素，立方晶化合物の含有体積を求めた。これらの結果を、荷重：２９４Ｎで測定した合金内部のビッカース硬さと共に表３に示す。 Furthermore, the inside of the sample for cross-sectional observation is observed to take a structure photograph, and using an image processing apparatus, WC, metal binding phase, chromium carbide phase (mainly Cr 7 C 3 ), free carbon, cubic compound content The volume was determined. These results are shown in Table 3 together with the Vickers hardness inside the alloy measured at a load of 294N.
表１〜３の結果から、添加した炭化クロム量と炭素量が多い本発明品は、殆どが遊離炭素を含有しており、いずれも表面に炭化クロム層が形成されているが、炭化クロム量あるいは炭素量の少ない比較品では、炭化クロム層が形成されないことが分かる。ここで、本発明品３と４は遊離炭素を含まないが、浸炭処理によって表面部のみが高炭素となったために、炭化クロム層が形成されたものと考えられる。 From the results of Tables 1 to 3, the present invention products with a large amount of added chromium carbide and carbon content mostly contain free carbon, and all have a chromium carbide layer formed on the surface. Or it turns out that a chromium carbide layer is not formed in a comparative product with a small amount of carbon. Here, although the products 3 and 4 of the present invention do not contain free carbon, it is considered that a chromium carbide layer was formed because only the surface portion became high carbon by the carburizing treatment.
実施例１で得られた超硬チップの内、本発明品２，３，４，５および比較品２，３，４，５について、３２０＃の炭化ケイ素砥粒を含有したナイロン製ブラシで研磨することにより、切れ刃付近の逃げ面，すくい面，ブレーカ面を平滑にすると共に、切れ刃部に半径０．０２ｍｍのホーニングを形成して切削試験用チップとした。ブラシ研磨後の切れ刃断面を観察した所、本発明品の刃先のホーニング部では炭化クロム層が除去されていたが、刃先から０．０５ｍｍ以上離れた部分ではほぼ完全に炭化クロム層が残存していた。 Of the cemented carbide tips obtained in Example 1, the inventive products 2, 3, 4, 5 and the comparative products 2, 3, 4, 5 were polished with a nylon brush containing 320 # silicon carbide abrasive grains. As a result, the flank, rake face, and breaker surface near the cutting edge were smoothed, and a honing with a radius of 0.02 mm was formed on the cutting edge to obtain a cutting test tip. When the cross section of the cutting edge after brush polishing was observed, the chromium carbide layer was removed at the honing part of the cutting edge of the present invention product, but the chromium carbide layer remained almost completely at a portion separated by 0.05 mm or more from the cutting edge. It was.
さらに、比較品２の切削試験用チップについては、ＰＶＤ法による炭化クロムの被覆処理も行い、比較品１０を得た。成膜条件は、ホロカソード型イオンプレーティング装置を用い、ターゲット：金属クロム、反応ガス：アセチレン、雰囲気圧力：１Ｐａ、バイアス電位：−２００Ｖ、処理時間：３０ｍｉｎである。得られた被覆チップを断面観察した結果、被覆面積割合：１００面積％、平均厚み：３．０μｍ、成分：Ｃｒ23Ｃ6＋Ｃｒ7Ｃ3であった。 Further, with respect to the cutting test tip of the comparative product 2, the chromium carbide coating treatment by the PVD method was also performed, and the comparative product 10 was obtained. The film forming conditions are a holocathode ion plating apparatus, target: metallic chromium, reaction gas: acetylene, atmospheric pressure: 1 Pa, bias potential: −200 V, and processing time: 30 min. As a result of cross-sectional observation of the obtained coated chip, the coated area ratio was 100 area%, the average thickness was 3.0 μm, and the component was Cr 23 C 6 + Cr 7 C 3 .
こうして得た切削用チップを用いて、被削材：アルミニウム合金，切削速度：３５０ｍ／ｍｉｎ，切込み：３．０ｍｍ，送り：０．３０ｍｍ／ｒｅｖ，乾式の条件で外周連続の旋削試験を行った。１０分間切削した時点で、チップブレーカ面への被削材の凝着状態を観察し、被削材の仕上げ面粗さを測定した。また、５０分間切削した時点でチップ逃げ面の平均摩耗量を測定した。これらの結果を表４に示した。表４の結果から本発明品では、表面に形成された炭化クロム層により、チップ刃先に被削材が凝着しないために仕上げ面が美麗であり、また被削材と反応し難いために摩耗も少ないことが分かる。炭化クロムを被覆した比較品１０は、未被覆の比較品２より良好なものの、剥離し易いためか本発明品に及ばない。 Using the cutting tip thus obtained, a peripheral turning test was performed under the following conditions: work material: aluminum alloy, cutting speed: 350 m / min, depth of cut: 3.0 mm, feed: 0.30 mm / rev, dry type. . At the time of cutting for 10 minutes, the state of adhesion of the work material to the chip breaker surface was observed, and the finished surface roughness of the work material was measured. Further, the average wear amount of the tip flank was measured at the time of cutting for 50 minutes. These results are shown in Table 4. From the results of Table 4, in the product of the present invention, the finished surface is beautiful because the chromium carbide layer formed on the surface prevents the work material from adhering to the tip of the tip, and it is difficult to react with the work material. It can be seen that there are few. Although the comparative product 10 coated with chromium carbide is better than the uncoated comparative product 2, it does not reach the product of the present invention because it is easily peeled off.
実施例１で得られた本発明品２，８、比較品２，８の混合粉末をＩＳＯ規格でＳＮＧＡ１２０４０８の金型にて、実施例１と同様の条件でプレス成形，焼結を行ってチップ素材を作製し、２７０＃のダイヤモンド砥石で研削加工し、刃先部を３２０＃の炭化けい素砥粒を含有したナイロン製ブラシで半径０．０４ｍｍのホーニング加工を施した。これらを真空焼結炉に挿入し、雰囲気圧力が１０Ｐａの真空中で１２５０℃に１０分保持して再焼結することにより、研削面に炭化クロム層を形成させた。実施例１と同様の方法で測定した炭化クロム層の被覆面積割合と平均厚みの測定結果を表５に示す。 The mixed powders of the present invention products 2 and 8 and comparative products 2 and 8 obtained in Example 1 were pressed and sintered under the same conditions as in Example 1 with a die of SNGA120408 in accordance with ISO standards. The material was prepared and ground with a 270 # diamond grindstone, and the blade tip was subjected to a honing process with a radius of 0.04 mm with a nylon brush containing 320 # silicon carbide abrasive grains. These were inserted into a vacuum sintering furnace and held at 1250 ° C. for 10 minutes in a vacuum with an atmospheric pressure of 10 Pa for re-sintering to form a chromium carbide layer on the ground surface. Table 5 shows the measurement results of the coating area ratio and the average thickness of the chromium carbide layer measured by the same method as in Example 1.
そして、再焼結して得られたこれらのチップをＣＶＤコーティング装置を用いて、Ｈ2，ＨＣｌ，Ａｒ，Ｎ2，ＴｉＣｌ4，ＣＨ3ＣＮ，ＣＯ2，ＡｌＣｌ3などの混合ガスを９５０〜１０５０℃に加熱することによって、基材側から膜厚０．５μｍのＴｉＮ，膜厚４．５μｍの柱状晶ＴｉＣＮ，膜厚１．５μｍのＡｌ2Ｏ3，膜厚０．５μｍのＴｉＮの総膜厚７．０μｍの被膜を被覆し、本発明品１２，１３と比較品１０，１１の表面被覆超硬工具チップを得た。 These chips obtained by re-sintering are mixed with a mixed gas such as H 2 , HCl, Ar, N 2 , TiCl 4 , CH 3 CN, CO 2 and AlCl 3 using a CVD coating apparatus. By heating to 1050 ° C., the total of TiN with a thickness of 0.5 μm, columnar crystal TiCN with a thickness of 4.5 μm, Al 2 O 3 with a thickness of 1.5 μm, and TiN with a thickness of 0.5 μm from the substrate side. A film with a thickness of 7.0 μm was coated to obtain surface-coated carbide tool tips of the inventive products 12 and 13 and the comparative products 10 and 11.
次に、各工具チップ５個を用いて、被削材：Ｓ４５Ｃの４本溝入り，切削速度：１５０ｍ／ｍｉｎ，切込み：２．０ｍｍ，送り：０．４０ｍｍ／ｒｅｖ，湿式の条件で外周断続旋削試験を行った。断続切削による衝撃回数が１万回の時に切れ刃を観察した結果、膜剥離（チッピング）が発生したチップと正常なチップの個数の割合、および正常なチップでの逃げ面摩耗量の平均値を表５に併記した。 Next, using 5 tool tips, the work material: S45C with 4 grooves, cutting speed: 150 m / min, cutting depth: 2.0 mm, feed rate: 0.40 mm / rev, outer periphery intermittent under wet conditions A turning test was performed. As a result of observing the cutting edge when the number of impacts due to intermittent cutting was 10,000 times, the ratio of the number of chips with chipping (chipping) and the number of normal chips, and the average value of the flank wear amount with normal chips This is also shown in Table 5.
本発明品は、基材と膜との密着性に優れるため、膜剥離およびこれに伴うチッピング摩耗が少ない。 Since the product of the present invention is excellent in adhesion between the substrate and the film, there is little film peeling and chipping wear associated therewith.
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| CN111996432A (en) * | 2020-09-02 | 2020-11-27 | 四川大学 | Preparation method of ultra-coarse hard alloy material |
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| CN111996432A (en) * | 2020-09-02 | 2020-11-27 | 四川大学 | Preparation method of ultra-coarse hard alloy material |
| CN111996432B (en) * | 2020-09-02 | 2021-02-12 | 四川大学 | Preparation method of ultra-coarse hard alloy material |
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