It is understood that China's pharmaceutical packaging machinery industry has basically formed a technological innovation model that focuses on large and medium-sized backbone enterprises, supported by research institutes and institutions of higher learning, and combines production, study and research. However, the overall situation is large but not strong, the quality is not high, the ability for independent innovation is weak, and the international competitiveness is not strong.
Compared with developed countries, the product and technology gaps in the pharmaceutical packaging machinery industry in China are mainly reflected in the following aspects: From the perspective of product structure, there are only 1,300 varieties of packaging machinery in China, such as pillow packaging machines, tea packaging machines, and granular packaging. Machines and other models, its supporting a small number, lack of high-precision and large-scale chemical products, can not meet market demand: product quality gap in the performance of the product is low, poor stability and reliability, aesthetic appearance is not beautiful, rough surface treatment, many components Poor quality, short life, and low reliability affect the overall product quality.
In addition, the domestic packaging machinery industry lacks leading enterprises, and there are not many companies with large production scales and high product quality. From the viewpoint of product development, China still remains at the stage of testing and imitation, and has weak self-development capabilities, and lacks scientific research and production pilot bases. Only 1% of sales, while foreign as high as 8% to 10%.
In addition, due to the impact of the international financial crisis in recent years, the growth rate of the national drug packaging machinery companies has slowed down. One important reason is that large-scale pharmaceutical packaging machinery companies are almost all imported equipment, and domestic equipment is lacking. Another important reason is that most of China's small and medium-sized pharmaceutical machinery enterprises are difficult to meet the market access requirements, limiting the space for drug packaging machinery.
In fact, the potential for the development of the pharmaceutical packaging machinery industry in China is enormous. Only under pressure from the industry to require low-cost and high-efficiency, the pharmaceutical packaging machine industry needs to make changes in its business strategy in order to obtain a reasonable profit. Improve the level of pharmaceutical packaging equipment, adapt to high-efficiency, low-volume production, and improve the applicability of pharmaceutical packaging companies to pharmaceutical 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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