"Beijing-Tianjin-Hebei joint defense and joint defense to solve the problem of air pollution, government procurement will have a lot to do. Improve the compulsory procurement and priority procurement system, and increase the proportion of 'greening' of government procurement, to promote the solution of this problem." National Committee of the CPPCC Xiong Guili According to an interview, the reporter said.
At present, the coordinated development of Beijing-Tianjin-Hebei has become a major national strategy. In view of the fact that there are still some difficulties and challenges in the prevention and control of air pollution in Beijing, Tianjin and Hebei, Xiong Guili recommends:
First, it is necessary to scientifically compile the regional ecological environment plan of Beijing-Tianjin-Hebei on the basis of deepening the analysis of pollution sources.
Second, improve energy transmission and distribution capabilities in all aspects.
Third, we must improve the quality of oil products in the Beijing-Tianjin-Hebei region to promote vehicle emission reduction. Accelerate the standardization of large vehicles and upgrade oil products, speed up the elimination of old and yellow-standard vehicles, and eliminate the sale and use of counterfeit vehicles. Continue to promote and popularize new energy vehicles. The parking spaces for newly built commercial houses should be equipped with charging power supplies, build charging piles in public places, set up special parking spaces, and plan the renovation of charging facilities for the old communities. Public transport, sanitation, and government vehicles must take the lead in electrification.
Fourth, we must increase government input and support. First, we must further rationalize the input mechanism and achieve the supporting development of investment funds and projects; second, increase tax subsidies and promote the elimination of backward production capacity. To implement more stringent loan standards for the “two high†industries, increase credit support for enterprises to actively reduce emissions and pollution, actively use financial leverage to protect the environment; third, improve compulsory procurement and priority procurement systems, and improve government procurement. The proportion of “greeningâ€; the fourth is to promote the pilot of regional emissions trading in the Beijing-Tianjin-Hebei region, focusing on the steel, power, petrochemical and other industries, and gradually establish a price mechanism that reflects the scarcity of resources and the cost of environmental restoration.
Fifth, further create a more favorable market environment. Actively cultivate the main body of energy-saving market, focus on promoting the development of energy-saving service companies, increase funding and policy support for energy-saving service companies, and especially increase support for private energy-saving and environmental protection service companies, providing market access, finance, taxation and finance. Policy support to guide private capital into the energy conservation and environmental protection service industry. In addition, it is necessary to further guide capital entry through capital market and bank credit, and promote the diversification of financing loan channels of energy conservation service companies.
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:
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.
Tungsten carbide roller material design
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.
Tungsten carbide roller category
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 roller production process control
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.
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