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

In the bearing and standard parts industry, steel balls and screws are produced using highly efficient automatic cold heading machines. These machines have high production rates, but for medium and large-sized steel balls, the life and efficiency of the matching alloy steel dies are reduced due to the following factors during the cold heading process:

Wear and deformation caused by the intense flow of the deformed metal on the die surface. Sometimes, the die cavity surface is scratched, abraded, or even adhered to, which easily causes dimensional errors and scrapping of the die, resulting in poor product quality.

The die cavity is easily deformed due to the relatively insufficient yield strength of the matrix material.

After continuous and repeated stress, especially in areas with stress concentration, the fatigue life of the alloy steel is relatively low, leading to fatigue failure as the number of heading operations increases.

Therefore, in addition to further improving the life of alloy steel dies, there is a widespread demand for a new material that is both wear-resistant and has good toughness to adapt to the development of the cold heading industry.

Test Results and Application Assessment

To expand the application field of cemented carbide and meet the urgent demand of steel ball factories for large-sized steel ball cemented carbide dies, based on our long-term work experience and domestic and foreign data collection, we finally selected a specially made coarse-grained WC powder, supplemented by an appropriate binder phase, to formulate YGC-I and YGC-Ⅱ coarse-grained cemented carbides (YGC-Ⅱ has a higher binder phase content than YGC-I). The conventional performance data of YGC-I and YGC-Ⅱ are shown in Table 1.

An Application of Coarse-Grained Cemented Carbide in Cold Heading Dies for Steel Balls 2

To study the effect of different particle sizes of WC powder on the fracture toughness of cemented carbide, fine-grained cemented carbide YG10X, medium-coarse grained cemented carbide YG18C, and YG20C were also prepared.

The fracture toughness of fine-grained, medium-coarse grained, and super-coarse grained cemented carbides with three different WC particle sizes was measured, and the results are shown in Table 2. It can be observed from Table 2 that as the WC particle size changes from fine-grained to medium-coarse grained and then to coarse grained, the fracture toughness of the alloy increases significantly, or even doubles. Even within the same particle size range, the fracture toughness of the alloy also increases with the increase of the binder phase content. This indicates that there are two ways to improve the fracture toughness of the alloy: first, by selecting coarse-grained WC powder, and second, by increasing the binder phase content of the alloy.

An Application of Coarse-Grained Cemented Carbide in Cold Heading Dies for Steel Balls 3

carbide material for cold heading

Selected YGC-I and YG10X samples were used to take scanning electron microscopy (SEM) fracture photos. Figure 1a shows the SEM fracture photo of YGC-I, and Figure 1b shows the SEM fracture photo of YG10X. Careful observation of the SEM fracture photos reveals that YGC-I has coarse grains and a thick binder phase layer, with cracks extending along the binder phase, resulting in mostly intergranular fractures and thus a higher fracture toughness K?C. In contrast, YG10X has very fine grains and a very thin binder phase layer, with mostly transgranular fractures, leading to a lower fracture toughness K?C. This indicates that the trend in fracture toughness values of carbides with different grain sizes is consistent with the conclusions drawn from the analysis of SEM fracture photos.

The aforementioned coarse-grained cemented carbide developed was applied to cold heading larger specification steel balls φ17.4625 and φ19.05. After being used on a Z32-28 machine at a certain factory, the usage data show that the coarse-grained cemented carbide is capable of stamping larger specification steel balls, and its die core life is more than 8 to 10 times longer than that of GCr15. This not only expands the application scope of cemented carbide but also provides the possibility for the bearing industry and standard parts industry to adopt carbide dies with larger heading forces. Moreover, due to the significant increase in die life, it brings about considerable economic benefits.

Вывод

1.Selecting specially made coarse-grained WC powder and correspondingly increasing the binder phase content of the alloy is an effective way to improve the fracture toughness of cemented carbide.

2.SEM fracture analysis indicates that coarse-grained cemented carbide fractures are mostly intergranular, resulting in a higher fracture toughness K?C, while fine-grained cemented carbide fractures are mostly transgranular, leading to a lower fracture toughness K?C.

3.The usage results show that the life of coarse-grained cemented carbide die cores is more than 8 to 10 times longer than that of GCr15.

4.In summary, for the stamping of larger specification steel balls, choosing coarse-grained cemented carbide is a reasonable option.

Добавить комментарий

Ваш адрес email не будет опубликован. Обязательные поля помечены *

91孕妇精品一区二区三区| 啊啊啊操我视频大全| 美女肏肏逼应用下载| 把美女日到高潮喷水视频| 乱伦美女小骚货视频| 最新AV中文字幕在线看| 最新免费高清无码片| 国产裸模大尺度私拍视频| 激情久久久久久久久久久| 国产日韩精品v一区二区| 日韩高清毛片在线观看| 亚洲国产综合精品 在线 一区| 美女被大屌操大骚逼| 色综合色狠狠天天综合色| 中文字幕在线资源第一页| 日本高清一区二区三区在线观看| 鸡巴操骚逼视频播放| 在线无码一区二区三区不卡| 日韩久久奶茶视频| 两人爽爽爽无码免费视频| 97人妻精品一区二区三区视频| 久久久国产精品亚洲无码| 亚洲综合欧美日韩| 操大美女逼射精视频| 午夜性刺激在线视频免费| 欧美一区二区三区身体| 被医生添奶头和下面好爽| 九九视频这里只有精品| 最新的精品亚洲一区二区| 午夜性刺激在线视频免费| 欧美一区亚洲一区视频在线观看| 日韩精品诱惑一区?区三区| 亚洲 自拍 欧美 一区| 男生的小鸡鸡插进女生的桃子 里| 午夜场射精嗯嗯啊啊视频| 天天摸天天添人人澡| 啊啊啊操我视频大全| 九九热在线精品免费看| 久久精品欧美日韩精品不卡| 白丝袜子宫啊啊啊不要了| 亚洲国产日韩欧美高清片|