I believe many of my card friends have found that in addition to the layout lights on the top of the cabins of many medium- and heavy-duty trucks in China, there are three small lamps placed side by side in the middle of the cab, from the initial green color to the red yellow ones. White is also quietly changing. I believe many card members will have such a question in mind. What do these three lamps do? These three lights are actually called speed indicator lights. To lift these three lights, you have to mention Japanese trucks. Because of the large potential risk of large trucks, Japan has set up appropriate safety warning standards in order to better alert passers-by or other vehicles. In 1967 (Showa 42), Japan's relevant management structure made adjustments to road safety regulations and proposed the requirements for installing speed indicators. At that time, vehicles with a maximum load of 5 tons or a total cargo weight of 8 tons or more were required to be installed. When the early regulations were introduced, many of the speed indicator lights were designed as separate units. At that time there was a clear rule for the speed indicator light, which was to be seen at a position 100 meters from the front of the vehicle. Mounting height also has specific provisions, the light color is defined as yellow-green. And if the lamp is damaged, it should be able to know in the cab, so the cab instrument has a reminder alarm function. A screenshot of a movie, some of the Mitsubishi truck speed indicators lit So how does this speed indicator work? First of all, only one lamp is lit at a vehicle speed of 40 km/h or less. In 40-60 rooms, two lamps are lit. After 60, all three lamps are lit, and this lamp is not controlled by a manual switch. It is controlled by the speed signal. When the vehicle is stopped, all three lights should be off. Moreover, there are specific provisions for the positions where the three lights are on at different speeds. For details, please refer to the figure notes. This Isuzu heavy truck should not be unfamiliar with the classic speed indicator In 1999, the corresponding regulations on road safety in Japan were adjusted and the lamp was abolished. This lamp has also become history. Why should we abolish this lamp that involves safety performance? There are only two reasons. The first is that large trucks cost a lot of money to match this speed indicator light. The second is that even though this lamp law requires the equipment to be installed, because too many people do not know the meaning of the system, it is actually There is no use for it and it is abolished. After the mandatory speed limit device is installed, the speed lights are even more meaningless. In addition to the speed indicator light does not play a corresponding role, there is a reason that the safety rate limiting device is generally used, the truck speed is limited to 90 km / h, and the device can not be dismantled without authorization, if removed or protection is not in place , may be severely punished when testing. This regulation also affects the import and export of Japanese trucks. What kind of car is this? 2001 Mitsubishi Fuso heavy truck change cancelled the speed indicator Accompanied by the requirement of abolishing the speed indicator lamp in the Japanese regulations in 1999, this unique safety indicator light for Japanese trucks has gradually left the stage of history in the island countries. In the following years, many manufacturers also canceled the product switching. The configuration of the speed indicator light, such as the 2001 Mitsubishi Trucks' small-scale switching of products, a significant change in its appearance is to cancel the speed indicator. There is a fact that we have to admit that it is the far-reaching impact of Japanese trucks on the development of trucks in China. During the period of universal application of the speed indicator lights from 1967 to 1999, China’s medium-heavy trucks were also in a period of rapid development. At that time, many domestic manufacturers had selected Japanese truck companies as targets for the introduction of technical cooperation. The configuration of the speed indicator lights of Japanese trucks has also entered the country. Mentioned in the domestic cab with the speed indicator light truck, let the author's deepest impression is liberated. In the late 1980s, when FAW Liberal and Japan signed a contract for technology import projects, while the Nissan cabstar's cab opened the era of small liberation light trucks, it also introduced Mitsubishi FK, FM, and FP series cabs. In 1995, the third-generation Jiefang truck J3 series was officially launched. Its classic four-party cab left a deep impression on many people. Not only did the speed indicator light on the long-duration cab of the early liberation It should be pointed out that at that time, the liberation of flat-head trucks was not equipped with speed indicator lights, and some Mitsubishi trucks imported into the country were also not equipped, and presumably they were castrated. In the year 2000 or so, it was said that there were sales of accessories for speed indicator lights on the market, and the colors were optional. The middle lights were the most common in red. At that time, many card friends would choose to use them for modification. At that time, it could be said that it was a matter of pulling the wind. . Later, the liberation of flat-head trucks basically started with standard speed indicators, until the April 2008 release of J6 at the FAW Liberation Beijing Motor Show. All J6 liberation models displayed at the show were equipped with a speed indicator, and all were It is a green shade that follows the Japanese system. According to the old card friend introduction, the early liberation speed indicator light will be displayed according to the speed, then basically this function is cancelled, become the pure decorative lamp. In the Liberation J6L, the card is also equipped with this light. In recent years, the lampshade has also become white, controlled by the light switch. Of course, in addition to the liberation of heavy trucks, there Futian Auman heavy truck, the first generation of the seemingly northbound Auman H1 truck did not see the speed indicator. However, after the start of the second-generation Auman heavy truck, Auman chose the Isuzu technology heavy-duty cab, equipped with speed indicators on the Shenzhou, Lions, and later ETX series. Through the instrument output vehicle speed light control signal, when the speed reaches 20km/h, 40km/h and 60km/h respectively, the speed light above the cab is lighted to remind the opposite driver to pay attention to the safety of the vehicle (although many people do not know the same The role of the lamp). Later, when Foton Auman introduced the GTL heavy truck, Auman still retained the three Japanese-style speed indicators even though the car used a Mercedes-Benz cab. Only the color of the shade is yellow. Later, on the recently launched EST truck, the speed lights disappeared and disappeared on the super-powered ETX. It seems that Auman intends to give up the three lights. Speed ​​light above the legendary Ssangyong Mercedes-Benz? ? Of course, in addition to the domestic and foreign, the early development of Korean trucks was also affected by Japanese trucks. The speed indicator lights were also seen in modern trucks, Ssangyong trucks, and Daewoo trucks at that time. Some of these brands have been imported into the country, and some have even been introduced to the domestic technology cooperation, such as the cooperation of modern and Jianghuai Geerfa, Shuanghui and SAIC Huizhong, this rich Japanese style configuration also followed. Although it is a simple three small lamps, its original intention is designed for safety. After Japan was canceled, these three small lamps were also popular in the country. From safety warnings, they gradually became so-called decorative lights. The development of so many years is also really embarrassing, with the gradual development of domestic trucks towards the European style trend, presumably this three Japanese style with rich Japanese style will gradually fade out of the application. (Text/Figure Yang Jianwei)
Tungsten carbide roller has characteristics of good wear resistance, high temperature red hardness, thermal fatigue resistance and thermal conductivity and high strength , have been widely used in high-speed wire rod, bar, rebar, seamless steel tubes, etc. Domestic production of tungsten carbide roller materials mostly WC- Co, WC- Co- Ni- Cr two series, and the content of Co, Co- Ni - Cr is in the range of 6wt% ~ 30wt%. From the use of perspective, tungsten carbide rollers has good mechanical properties, its flexural strength up to 2200 MPa or more, shock toughness up (4 ~ 6) × 10^6 J/ m^2, Rockwell hardness (HRA) is up to 78 to 90, widely in the high-speed wire rod rolling process, which is much higher than single-slot chilled cast steel or high speed steel rolls.Tungsten carbide is made of Tungsten Carbide Powder and binder phase (such as drilling, nickel, etc.), and then pressing and sintering, regardless of the conditions under cold rolled or hot rolled has excellent wear resistance, tungsten carbide rollers has been widely used in pre-finishing mill and finishing of high-speed wire rod currently. On the performance of tungsten carbide roller in hot-rolling wire rod , the material must meet the following requirements:
Tungsten carbide roller material design
Tungsten carbide roller category
Tungsten carbide roller production process control Carbide Roller,Carbide Ring,Mill of Rolling Line,Steel Wire Rod,Mill Rolling Finish Stand,Mill Roller Groove Type Luoyang Golden Egret Geotools Co., Ltd , https://www.xtchvof.com
1. Sufficient anti-fracture strength;
2. Good abrasion resistance;
3. The smooth surface finish;
4. Excellent corrosion resistance, thermal fatigue, thermal cracking performance.
Tungsten carbide roller rings can working in bad conditions , small profile rolling (especially rebar rolling) process conditions is harsher than the high-speed wire rod, and therefore corresponds to the profile rolling ,tungsten carbide rollers recommend using high binder phase carbide.
Pre-finishing all vehicles roller should ensure its high toughness, strength, rigidity and thermal conductivity, followed before considering its wear resistance. When designing each vehicles roller, pre-finishing materials should choose carbide grades of Co, Co- Ni- Cr binder content is high (greater than or equal to 25wt%) , requiring an average WC grain size of coarse (5μm ~ 6μm), to obtain a higher shock toughness, proper strength and hardness. For the finishing of the roller movements, particularly the last two rollers of the finish rolling, which suffered load is small, and high relative velocity of the material to be pressed (80 m / min ~ 120 m / min). In this case, the wear resistance of the roller to be the most important requirements, and must ensure the strength , timpact toughness and hardness of a reasonable match, so the binder of Co / Ni content ratio and the average grain WC control of particle size and other factors must have greater control in front of different pre-finishing rolling roll.
According to the structure of tungsten carbide rollers, it can be divided into solid tungsten carbide roller and composite tungsten carbide roller. Solid tungsten carbide rollers have been widely used in pre-finishing and finishing stands high speed wire rod mill (including fixed reducing the rack, pinch roller rack). Composite tungsten carbide roller is made of cemented carbide and other materials, and it can be divided into tungsten carbide composite roll rings and solid tungsten carbide composite roller. Tungsten carbide composite roll rings mounted on the roller shaft; solid tungsten carbide composite roller will be directly cast in the roll axis to form a whole, a large load is applied to the rolling mill.
Tungsten carbide rollers produced by powder metallurgy method, the key to its process control is the chemical composition of the material and the mixture was prepared, pressed molding, sintering and deep processing and other preparation process parameters.
1. Preparation of starting material (WC focus quality): As the WC raw material and quality control of the use of different levels of quality may fluctuate, resulting in adverse effects on microstructure.
2. Preparation of the mixture: Mixture preparation is the key to the production process of the roller, the roller of failure modes - trachoma, mainly generated by this procedure.
3. Pressing: roller pressing is an important process of the roller mill.
4. Sintering: roller sintering is to determine the final quality of the roller production processes, use of advanced low-pressure sintering technology, HIP sintering technology can greatly improve the performance of roller.
5. Deep processing: deep processing rollers have a greater impact on the quality and accuracy of the roller surface.