Because the real environment and working conditions in the actual use of marine air compressors are not fully simulated by the laboratory, such as the working environment of the air compressor, most of the time is in the sea swing state and the high vibration, high temperature and high humidity of the engine room. In the case of an air compressor that already has practical experience, the best data source for its reliability assessment is its own fault data record. The failure of the various components of the air compressor leads to the failure of the whole machine. The reasons are various, such as defects in the design structure, incorrect operation or corrosion and aging of the material. These reasons lead to uncertainty in the failure time of the air compressor. Characterizing this time using statistical methods is called the 'black box' method. The expiration time is taken as a random variable and described by an appropriate probability distribution function. The basic principle of 1Weibull distribution linear regression considers that the Weibull distribution is the most suitable model for analyzing the reliability of mechanical products. Therefore, the collected goodness test of the air compressor fault record data is based on the Weibull distribution. Progressive analysis of the reliability of air compressors. The cumulative fault distribution function B-4 of the two-parameter Weibull distribution is an optimization process when estimating the parameters of the Weibull distribution. The accuracy of the prediction is improved by minimizing the degree of deviation between the regression estimate and the observed value. Sexuality 0. For the 4th Pearson, the modern high-resolution active sonar background reverberation is of great significance. Therefore, it is of great significance to study the CFAR detector design problem under the Pearson distribution reverberation background. In this paper, two kinds of CFAR detectors OSGO and OSSO with multi-target interference resistance are proposed. The false alarm probability and detection probability of the two types of detectors are derived. The performance of OSSO is better than that of traditional OS. The performance of OSGO is similar to that of OS, but 2 Class detectors require only half the computational overhead to facilitate application in array signal processors. The research results of this paper can be extended to the radar field. The next step is to study the detection problem of distance-expanded targets in the Pearson distribution reverberation background.
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.xtclasercladding.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.
Research on Reliability of Marine Air Compressor Based on Field Data