It is expected that in the next three days, most of the Sichuan Basin, southeastern Gansu, central and southern Shaanxi, southern North China, north and south of Huanghuai will have heavy rains, and there will be heavy rains in the northeastern part of Sichuan and southwestern Shaanxi. It is necessary to prevent the adverse effects that local heavy rainfall may have.
Yesterday, the national precipitation was relatively scattered. The large-scale heavy rainfall was concentrated in the northeastern part of Sichuan, southwestern Shaanxi, northern Anhui, central Jiangsu and other places. The rainfall level generally reached moderate to heavy rain, local rainstorms and even heavy rains. Among them, the 24-hour rainfall in Zhenba and Henan in Shaanxi reached 63 mm and 79 mm respectively.
The Central Meteorological Observatory predicts that due to the combined effects of weak air-conditioning and southerly warm and humid air currents, from July 7 to 9, most of the Sichuan Basin, southeastern Gansu, south-central Shaanxi, southern China, north and east of Huanghuai, western Yunnan, and southwestern Guangxi There will be heavy rains in other places, and there will be heavy rains in the northeastern part of Sichuan and southwestern Shaanxi.
Among them, there are heavy rains in southeastern part of Gansu, southwestern Shaanxi, most of Sichuan Basin, southeastern part of North China, north of Huanghuai, eastern Jianghuai, western Yunnan, and southwestern Guangxi. Among them, there are local areas in the northwestern Sichuan Basin and southwestern Shaanxi. Heavy rains (100~150 mm); in addition, there are small to moderate rains or thunderstorms in the eastern part of the northwestern region, most of northern China, and central and eastern Inner Mongolia. The above-mentioned local areas will have strong convective weather such as short-term thunderstorms and strong winds.
Graphite Block is a solid shape, which is usually made of artificial Graphite , graphite mould and so on. It also has small graphite blocks made of Flake Graphite , such as a carbon brush. Graphite is mostly powder, such as soil Graphite Powder , flake graphite and other powder.
Graphite blocks for silicon carbide furnace, graphite furnace and other metallurgical furnaces, resistance furnace for lining and conductive materials, and opaque graphite heat exchangers. Widely used in electronics, metallurgy, chemical industry, steel and other fields, the product quality is excellent, the performance is stable.
The function and use of high purity (isostatic pressure) graphite blocks
Production and processing of various materials, specifications of the graphite rods, graphite products, graphite block, graphite block, graphite plate, graphite tubes of rotary kiln, High Purity Graphite crucible, graphite ring, graphite boat graphite products, such as the opposite sex, with high temperature resistance, good thermal conductivity, melting high purity, strong corrosion resistance, long service life, etc. Create the graphite block of special rotary kiln in rotary kiln, including kiln head, kiln tail graphite block and Graphite Seal Block. With long service life, the attached impurity content is very few, with high volume density and strong anti-folding ability.
Graphite, graphite, soft, black grey; It has a greasy feel and can contaminate paper. The hardness is 1 ~ 2, and the hardness can be increased to 3 ~ 5 along the vertical direction with impurities. The proportion is 1. 9 ~ 2. 3. Scope of specific surface area is focused on the 1-20 m2 / g, under the condition of starvation, its melting point above 3000 â„ƒ, is one of the most heat-resistant mineral. It conducts electricity and conducts heat.
There is no pure graphite in nature, which often contains impurities such as SiO2, Al2O3, FeO, CaO, P2O5 and CuO. These impurities often appear in the form of quartz, pyrite, carbonate and other minerals. In addition, there are water, asphalt, CO2, H2, CH4, N2 and other gas parts. Therefore, in addition to determination of fixed carbon content, the content of volatile and ash content must be measured.
The technological properties of Natural Graphite classification graphite are mainly determined by its crystalline form. The crystalline form of graphite minerals has different industrial values and USES.
1. Dense crystalline graphite:
Dense crystalline graphite is also called blocky graphite. Such graphite crystals are clearly visible to the naked eye. The particle diameter is greater than 0. 1mm, which is concentrated in 0.1-1m2/g than surface area, and the crystal is arranged in a disorganized and dense block structure. This kind of: the characteristic of graphite is high grade, the average carbon content is 60 ~ 65 %, sometimes reach 80 ~ 98%, but its malleable and slippery sex is not as good as flake graphite is good.
2. Special Graphite:
Graphene is widely used in industry and is used in almost every industry. Industrial use of synthetic graphite, or special graphite. According to its forming way can be divided into the following kinds.
1. Isostatic pressure graphite, the three high graphite that many people call, but not the third height is isostatic pressure.
2. Pressed graphite.
3. Extruded graphite, mostly electrode material.
(1) processing speed is faster: usually, graphite's machining speed can be 2~5 times faster than that of copper; The discharge process is 2~3 times faster than copper.
The materials are more difficult to deform: the advantages of the thin rib electrode are obvious. The softening point of copper is around 1000 degrees, which can be easily distorted by heat. The sublimation temperature of graphite is 3650 degrees. The thermal expansion coefficient is only 1/30 of copper.
(2) lighter weight: the density of graphite is only 1/5 of copper, and the large electrode can reduce the burden of machine tool (EDM). It is more suitable for use in large mould.
(3) smaller discharge consumption; Because the spark oil also contains C atoms, in edm, high temperature lead to spark came out of the oil C atoms are broken down, turned on the surface of Graphite Electrode form a protective film, compensate the loss of the graphite electrode.
(4) no burrs; After finishing, the copper electrode needs to be repaired by hand to remove the burrs. However, graphite processing has no burrs. It saves a lot of cost and is easier to realize automatic production.
(5) graphite is easier to grind and polish; Because graphite's cutting resistance is only 1/5 of copper, it is easier to grind and polish by hand.
(6) lower material cost and more stable price; Due to rising prices in recent years, and now isotropic graphite copper price is lower, under the same volume, the universality of toyotanso graphite products price is 30% ~ 60% lower than the price of copper, and the price is more stable, short-term price fluctuations is very small.
It is this incomparable advantage that graphite products gradually replace copper as the preferred material for EDM electrode.
Graphite Block,Graphite Anode Plate,Rotary Kiln Graphite Block,Graphite Seal Block
Fengcheng Ruixing Carbon Products Co., Ltd , http://www.lnfcrxts.com