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Characteristics and Application of Tungsten Carbide Carbide
Carbide is a high hardness and melting point of the carbide, with Co, Mo, Ni as a binder sintered powder metallurgy products. Its room temperature hardness of up to 78 ~ 82 HRC, 850 ~ 1000 ℃ high temperature, cutting speed than high-speed steel 4 to 10 times higher. But the impact toughness and bending strength than the high-speed steel is poor, so rarely made the overall tool.
Tungsten carbide is a hard alloy family of raw materials, pure tungsten carbide is not commonly used for black hexagonal crystal, metallic luster, hardness and diamond similar to the electric, heat good conductor. Melting point 2870 ℃, the boiling point of 6000 ℃, the relative density 15.63 (18 ° C). Tungsten carbide is not soluble in water, hydrochloric acid and sulfuric acid, soluble in nitric acid - hydrofluoric acid mixed acid. Pure tungsten carbide fragile, if mixed with a small amount of titanium, cobalt and other metals, can reduce the brittle. Tungsten carbide used as a steel cutting tool, often added titanium carbide, tantalum carbide or their mixture, in order to improve the anti-explosive ability. The chemical properties of tungsten carbide are stable.
In tungsten carbide, carbon atoms embedded in the gap between the tungsten metal lattice, does not destroy the original metal lattice, the formation of gap solid solution, so called interstitial (or insert) compounds. Tungsten carbide can be obtained by heating the mixture of tungsten and carbon at high temperature, The presence of hydrogen or hydrocarbons accelerates the reaction. If the preparation of tungsten with oxygen compounds, the product must be vacuum at 1500 ℃ to remove carbon oxides. Tungsten carbide suitable for high temperature machining, can produce tungsten carbide cutting tools, furnace structure materials, jet engines, gas turbines, nozzles and so on.
Abrasive abrasive upstream and downstream enterprises have closed down?
Henan Province, environmental protection million people from the July 21 start, Henan Luoyang, Zhengzhou, Nanyang and other places of refractory materials, refractories, metallurgical materials manufacturers have discontinued. It is understood that the Xixia area metallurgical materials enterprises stop production rate of more than 70%. This can not help but surprise, as has 21 million inspectors are checked what?
First of all look at the inspection mission: July 21 stationed and propaganda launched; July 22 - August 12 inspection team stationed in the cities and counties, according to the town to do the work group; August 13-22 supervision and inspection; Before the end of the month
Stationed and propagated is the printing of environmental laws and regulations leaflets and environmental violations report details, in-depth urban and rural residents to issue publicity and environmental laws and regulations leaflets, environmental protection and illegal reporting awards rules and provincial government documents.
And then look at the details of all check Han:
First, the "scattered chaos" enterprises to conduct investigation
1, banned enterprises mainly include:
- (1) refractory materials, carbon production, lime kiln, brick kiln, non-ferrous smelting, ceramic firing, casting, rubber production, tanning, chemical, wire mesh processing, rolling steel, which is not in line with national industrial policy, local industrial layout planning , Cement grinding station, waste plastics processing, and related to the use of paint, ink, adhesives, organic solvents such as printing, furniture and other small manufacturing and processing enterprises 16 key industries and other polluting enterprises and production of individual industrial and commercial households ;
- (2) land, environmental protection, industry and commerce, quality supervision and other incomplete procedures, and can not improve the formalities of polluting enterprises;
- (3) illegal production and operation, serious pollution of small manufacturing, small processing, small workshops, etc .;
- (4) illegal operation, sales of poor quality oil "black gas station";
- (5) remediation enterprises overdue completion of remediation tasks.
- (1) Although the administrative licensing procedures, but the scope of illegal production and management.
- (2) pollution control facilities are not perfect, pollutant discharge is not compliance, serious environmental pollution.
- (3) May 31 before the completion of 10 tons of steam coal below the demolition of the task and do not meet the time limit to complete the VOCs of organic chemicals, catering and so on.
Second, electricity replacement, gas replacement for verification
- 1, check all completed dual replacement users;
- 2, to determine the way users replace the coal for electricity substitution or gas replacement
- 3, to determine the user to replace the equipment used.
Third, the verification of rural power grids
- 1, check all the need for rural power grid transformation of the village;
- 2. To determine the type of village where the grid needs to be transformed, as the central village or the poor village;
- 3, to determine the completion date of rural power grids, whether to complete the transformation task on schedule.
- Third, the coal burning treatment to check the situation
- 1, a comprehensive survey to find out the use of household users scattered coal;
- 2, a comprehensive investigation and registration of tea bath boilers, coal stove, operating small coal stoves and other coal burning facilities and equipment use;
- 3, a comprehensive investigation and registration of existing private coal sales outlets;
- 4, a comprehensive verification of clean coal production and warehousing supply center and distribution network construction and operation.
- Fourth, the dust construction site investigation
- The site of all the construction site of the Mo Pai, the site address, type of project, construction units and regulatory conditions to register.
- Fifth, complete the regional gas station census
- The traffic station administrative licensing procedures, business status of the census.
- Six, on the gas, wading business people exposed to smoke
- Pollutant emissions enterprises to conduct a comprehensive investigation, all gas, wading emissions enterprises to be registered one by one.
- Seven, the grassroots grid and site "three" management of the Mo Pai
- 1, census township (office), village (community) two grass-roots grid "one long three" and the site "three" to establish the authenticity.
- 2, ask the township (office), village (community) two-level grass-roots grid "a long three" and the site "three" duties and found the source of pollution after the handling procedures.
- 3, check the city (county), township (office) on the grassroots grid and site "three" training, inspectors assessment of the situation.
Eight, on the pollution source Mo Pai.
According to the Henan part of the refractory materials, raw materials and accessories cut production enterprises, August 13 to resume production, but from the inspection mission of the trip, August 13-22 supervision and inspection, so August 13 business can not be restored Production is unknown.
The contribution of molybdenum to lightweight steel for automobiles
Molybdenum (Mo) elements are very effective in the weight reduction of automotive steels, and also help to increase the strength and reduce the production cost.
The current share of greenhouse gas emissions in the transportation sector accounts for about 14% of the world's total emissions. In Europe, only the road transport industry accounted for as much as 20% of emissions, while the car's emissions accounted for 12%. Car manufacturers must strictly comply with the government's increasingly stringent emission regulations. European current law stipulates that all new cars per kilometer of carbon dioxide emissions shall not exceed the average level of 130g. By 2021, the average carbon dioxide emissions from car manufacturers must be less than 95g, which is significantly lower than the 123.4g 2015 standard.
In order to reduce fuel consumption and emissions, reduce body weight is one of the most effective way. Body weight per 100kg, per 100km of fuel consumption can save 0.1-0.5L, equivalent to 8-12g per kilometer of carbon dioxide emissions. In order to meet the increasingly stringent safety standards, manufacturers must be in the larger, with the price advantage of the model to seek further weight reduction.
For decades, lighter weight, higher strength steel has been widely used in the manufacture of body and chassis, high strength low alloy steel (HSLA) and advanced high strength steel (AHSS) has basically replaced the traditional mild steel. Different from magnesium alloy, aluminum alloy and other low-density materials, high-strength steel only a lower cost, mature manufacturing technology, you can complete its processing. Most of the high-strength steel car body and chassis in the white body of the total weight accounted for 60% -80%. Compared with the traditional body, widely used high-strength steel body weight can be reduced about 100kg.
Automotive steel must have both high strength, good formability and weldability. The alloy steel containing molybdenum has a specific metallurgical effect that allows the hard phase to have a very high strength. In the steel matrix, the mixed structure of the hard and soft phases achieves the perfect combination of high strength and high formability. Molybdenum can effectively regulate the coexistence of these different phases, which are present in stable and renewable forms under different production conditions. This means that steel can be produced in a more simple process, with greater flexibility in production and logistics. Although other alloying elements can achieve similar metallurgical effects, but the weight percentage, the role of molybdenum is most obvious.
Recently, molybdenum-containing automotive steels have replaced boron-containing steels for key components of B-pillars. DP800 and DP1000 and other molybdenum DP steel hydraulic forming parts can reduce the weight of the body 8kg, production and environmental benefits highlighted.
Environmental indicators are closely related to the automotive industry. Life Cycle Assessment (LCA) is mainly used to evaluate the environmental impact of product life. The analysis shows that the environmental impact of the new B column (hydraulic forming DP800 / DP1000 material) is significantly lower than that of the boron-containing steel column, assuming that the mileage of the vehicle is about 200,000 km. 8kg weight reduction can save considerable costs, reducing greenhouse gas emissions by 29%. (GWP) can save 165 kg of carbon dioxide (equivalent, gasoline driveline) and 141 kg of carbon dioxide (equivalent, diesel transmission), respectively, when the car mileage exceeds 200,000 km, which is equivalent to the car driving More than 1000km. In terms of production alone, the cost of steel smelting due to the weight reduction of components is much greater than the cost increase due to the addition of alloying elements.
Although HSLA steel and DP steel occupy a large proportion of automotive lightweight applications, a class of safety critical components such as automotive chassis plates and bumpers require higher strength steel. Technicians usually use high-strength steel at these locations, but in order to further reduce the weight, over the past decade has introduced ultra-high strength steel.
Thermoformed steel (PHS) is a popular new type of automotive steel, this whole martensitic steel through hot stamping and quenching process manufacturing, breaking the existing martensitic steel in the cold forming limitations, strength Higher than the advanced high-strength steel (AHSS), in some new models have been applied in the body structure of the weight can be reduced by 5% -10%, the global annual consumption of about 300 million tons. From the current development trend, PHS in the body structure of the proportion of the future is expected to reach 30% -40%. Volvo's latest model XC90 contains 38% PHS components.
PHS prone to bending deformation, stamping cracking and delayed cracking. Molybdenum and other key alloying elements play a very important role in optimizing the microstructure of PHS steel, which can significantly reduce the occurrence of failure. It is worth mentioning that, before quenching the austenite grain size, can avoid toughness fracture, improve energy absorption capacity and resistance to hydrogen brittleness. Increased grain boundary cohesion and dispersion of nano-precipitates can also improve the performance of steel. Laboratory and industrial pilot test results confirmed that niobium and molybdenum alloying treatment can achieve these goals. This once again shows that through the use of high-strength steel, the use of innovative manufacturing process can achieve some improvements, and molybdenum is enough to complete this great innovation.
The world's smallest man-made diamonds
People are making two-dimensional diamond manufacturing. New evidence suggests that this superhard form of carbon can be forged in a film called diamond. Graphite is a form of carbon found in a pencil that can be made into a thin film of only one atom, called graphene, and scientists have been trying to create a two-dimensional film of diamonds. Scientists have been working hard to create a two-dimensional film that can be called "diamonds".
The study found that with a few thousand times the earth's atmospheric pressure to compress a pair of graphene tablets, the crystal structure will change, which means that it has changed from graphite to diamonds. Luiz Gustavo Cancado, a physicist at the Bellevue Commonwealth University in Brazil, and his colleagues published this new discovery in the July 21 issue of the journal Nature.
"This is the thinnest diamond," says Pavel Sorokin, a theoretical physicist at MISIS in Moscow State University of Science and Technology, who has not been involved in the new study. "Now we can use it in the nano world Diamonds that exciting features. "In addition, diamonds are also predicted to be magnetic, which may be useful for spin electronics, which is a technique that utilizes electron spin to store data.
Scientists use a technique called Raman spectroscopy to monitor the structure of carbon crystals, which are irradiated on the material to observe how the vibrations of the atoms change under pressure. This method provides indirect evidence that the diamond has been formed. This method provides indirect evidence of diamond formation. The next step is to scatter x-rays or electrons to determine its structure.