Metal removing rate

In addition to then use in bonded and coated products, both natural and manufactured abrasive grains are used loose in such operations as polishing, buffing, lapping, pressure blasting, and barrel finishing. AH of these operations are characterized by very low metal removal rates and are used to improve the surface quaUty of the workpiece. 

High Speed Steels. Toward the latter part of the nineteenth century, a new he at-treatment technique for tool steels was developed in the United States (3,17) that enabled increased metal removal rates and cutting speeds. This material was termed high speed steel (HSS) because it nearly doubled the then maximum cutting speeds of carbon—low alloy steels. Cemented carbides and ceramics have since surpassed the cutting speed capabiUties of HSS by 5—15 times. 

Temperature, Kinetic order Order of Metal removal rate/... 

In competitive demetallation experiments the same rates do not necessarily hold. Hung and Wei (1980) reported that with both Ni-etio and VO-etio in the feed, the vanadium removal rate was the same as in the individual vanadium run, whereas the nickel removal rate was suppressed to below that of vanadium removal. In a related study using a mixed Ni-T3MPP and VO-etio oil, Webster (1984) reported that VO-etio de-metallated faster than Ni-TMPP and also suppressed the metal removal rate of the latter. This inhibition phenomenon offers a partial explanation as to why in most commercial operations with real feeds vanadium is more reactive than nickel. 

Numerous investigators have examined the kinetics of metal removal from petroleum fractions. The majority of studies have used conventional hydrotreating catalysts, Mo03 supported on y-Al203 and promoted with CoO or NiO. Metal removal rates have generally been interpreted using simple mass action kinetic expressions of the form... 

Data in Table XXVI reveals that metal removal rates are enhanced (m > 0) by increases in hydrogen partial pressure in accord with model compound studies. Both feedstock and demetallation catalyst may in-... 

Metal removal rates have generally been interpreted using a single kinetic rate expression of the form ... 

The open circuit potential as a function of time is a qualitative method that evaluates sacrificial coating stability. The sacrificial metal removal rate in the corroding solution is controlled by the potential difference of the underlying metal and the sacrificial coating, corroding solution, and sacrificial coating thickness. The open circuit potential changes to the protected metal when the sacrificial metal is completely removed. 

J.H. Chang, H. Hocheng, H.Y. Chang, A. Shih, Metal removal rate of Thiobacillus thiooxidans without pre-secreted metabolite, Journal of Materials Processing Technology, Vol. 201, pp. 560-564, 2008. 

In addition to faster metal removal rates and better tolerances compared to grinding methods using conventional abrasives, cBN wheels have the ability to produce lower workpiece temperatures during grinding, which reduces the potential for thermal damage. This can be of significant importance when critical components are being machined. 

Table 1 (McGeough, 1988) shows the metal machining rates that can be obtained when a current of 1000 A is used in ECM (currents from 250 to 10,000 A are common). Note that the metal removal rates are given in terms of volumetric machining rates as well as mass removal rates. The former is often more useful in practice.

Tool design continues to be of paramount importance in any ECM operation. The ingenuity of the tool designer will be tested continually as he endeavours to optimize electrolyte flows and metal removal rates, to produce the required size and shape of... 

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