欧美人妻精品一区二区三区99,中文字幕日韩精品内射,精品国产综合成人亚洲区,久久香蕉国产线熟妇人妻

Cemented carbide is made of refractory metal hard compound (hard phase),which is generally a carbide, and metal binder (binding phase)obtained by powder metallurgy method,. As a hard alloy for cutting tools, the commonly used carbides are tungsten carbide (WC), titanium carbide (TiC), and tantalum carbide(TaC), niobium carbide (NbC), etc. The mostly used binder is Co. The strength of the cemented carbide depends mainly on the content of cobalt.

Characteristics of Cemented Carbide 1Characteristics of Cemented Carbide 2Characteristics of Cemented Carbide 3Characteristics of Cemented Carbide 4

Because of the high melting point,high hardness (see Table 1-1),good chemical stability,and good thermal stability that carbides in the cemented carbide have and the large amount of high-temperature carbon materials, the hardness and resistance Abrasiveness and heat resistance are higher than high speed steel.
The main component of the hard alloy hard phase is WC. WC has good wear resistance.although some carbides have the same hardness and WC, but do not have the comparable wear resistance. Besides,WC has a higher yield strength (Table 1-2), so its resistance to plastic deformation is better. WC has good thermal conductivity, which is one of the most desirable properties for making tool materials. In addition. WC has a low coefficient of thermal expansion that is about 1/3 of steel.WC’s modulus of elasticity is three times that of steel, and its torsional modulus is twice that of steel. Therefore, the compressive strength of cemented carbide is also higher than that of steel. In addition, WC has good corrosion and oxidation resistance at room temperature, good electrical resistance, and high flexural strength. these excellent properties of WC have been passed to a hard alloy with its main component.

Characteristics of Cemented Carbide 5

Compared with high speed steel, the hardness of cemented carbide is HRA89-94, which is much higher than the hardness of HSS (HRC63-70 or HRA83-86.6). The maximum cutting temperature allowed for cemented carbide can reach 800-1000 °C or more, which could be much higher than HSS’s (550-650 ℃). The high temperature hardness of cemented carbide could be HRA82-87 at 540 °C,which is the same as the normal temperature hardness of high speed steel. The hardness at 760 ° C is HRA 77-85, and can maintained in HRA 73-76 at the environment of 1000-1100 ° C. Besides,Carbide’s wear resistance of cemented carbide is 16-20 times higher than that of the best HSS. Due to its high temperature hardness and wear resistance, cemented carbides have much higher cutting performance than high-speed steel and can increase tool durability by several tens of times. When machining ordinary structural steel, the cutting speed allowed is 4-10 times higher than that of high speed steel tools.
As a cutting tool material, cemented carbide is widely used (see Table 1-3)). In the turning process, except for a small number of small diameter bores and some non-ferrous metal workpieces, almost all of them can be processed with carbide turning tools. In the drilling process, in addition to the existing carbide drills, carbide drills, deep hole drills, carbide injection drills and indexable carbide drills have also been successfully used to machine steel. In addition, carbide end mills have been widely used. Others such as reamer, end mill, small modulus gear hob, medium and large modulus gears for hard tooth surfaces (such as m40 hob and m12 pin cutter), broaches and other tools use hard Alloys are also increasing. Although the proportion of cemented carbide in tool materials is lower than HSS and ranks second, its proportion of cutting chips is as high as 68%. (According to the 1979 US prof. of cemented carbide company that’s visited to China, in the United States, carbide cutting tools cut off 80% of cutting chips. ). According to reports, in some countries, more than 90% of turning tools and more than 55% of milling cutters are made of cemented carbide, and this trend continues to grow.

Dodaj komentarz

Twój adres email nie zostanie opublikowany. Pola, których wype?nienie jest wymagane, s? oznaczone symbolem *

日韩毛片一区视频免费在线观看| 日本一二区视频在线观看| 高清国产一区二区| 国产熟女视频一区二区三区| 男的日女生批网页| 泰国无码AV片在线观看| 波多野结衣福利视频| 黄网官方在线观看| 日韩激情视频在线看免费| 大黑屌狂操骚逼视频| 色男人天堂亚洲男人天堂| 操女人逼逼骚逼逼| 被几个大屌老外轮操| 女人日比比视频免费| 操女人大逼视频下载| 一级风流国产片a级| 男生狂操女生污视频| 五月天国产成人av在线| 玩弄邻居少妇呻吟11p| 中文字幕在线观一区二区| 日韩精品人妻一区二区免费| 老熟女被大鸡巴干| 国产品无码一区二区三区在线| 欧美日韩国产欧美| 国产又粗又猛又色又免费| 思思夜免费公开视频| 浪潮AV色综合久久天堂| 操我好舒服用力视频| 国产精品欧美久久久久久| 9国产亚洲精品国产| 狗狗大鸡巴狂操美女| 亚洲AV无码一区二区三区天堂古| 美女麻豆颜色光屁股眼子| 中文国产成人精品久久久| 骚片视频在线观看| 大粗鳮巴r教师人妻91| 成人黄色网破处在线播放| 爆乳喷奶水无码正在播放| 亚洲 欧美 日韩 主播| 日本十八禁大骚逼| 毛片日产av一区二区三区四区|