The morphology of surface/subsurface of nanostructured (n)WC/12Co and nAl_2O_3/13TiO_(2) coatings ground with different grinding parameters were investigated by using scanning electron microscope. The grinding force ratio and specific grinding energy were measured.

we tested the connection between the value of u(the specific grinding energy of PCD) and the parameters of grinding process,meanwhile,the experimental results show that: if u<25000J/mm~3,the grinding mechanism of PCD material is fatigue brittle removal;

In this paper are shown the respective grinding results of Al_2O_3-Mo cermet with diamond wheel on a cylindrical electrolytic grinder in different grinding ways (dry, wet and electrolytic). Grinding forces and specific grinding energy are measured. Ground surface and chips are observed by SEM.

when u>120000J/mm~3,the grinding mechanism is mechanical thermal removal and thermal chemical removal,and the fatigue brittle removal hardly takes place.

Studied the enhancement the grinding surface quality by high speed grind,after high speed rubs the speed change which truncates to rub truncates the experiment,confirmed the speed change rubs truncates the performance certain degree suppression high speed to rub truncates flutters.

The milling behaviour of these wheat lines was evaluated on an instrumented micromill which also measures the grinding energy and flour particle size distribution was investigated by laser diffraction.

The experimental investigation has shown that a major advantage of CBN grinding is that a substantially lower proportion of the total grinding energy enters the workpiece compared to grinding with alumina wheels.

The results show that the grinding energy can be accurately predicted by the application of the grinding force model.

Due to the previous paper, the workpiece burning occurs as the grinding energy is greater than the critical grinding.

Part(II): workpiece temperature and critical grinding energy for burni

The model was used to predict the total tangential and normal forces in surface grinding and the total grinding power in cylindrical grinding.

On the basis of a heat-transfer analysis, it is shown that some types of thermal damage can be predicted and controlled by inprocess monitoring of the grinding power.

It is generally necessary to reduce the grinding power in order to attenuate the restriction of thermal damages.

Since required grinding power increases exponentially as target size reduces, it is important to limit the tonnage sent to finer grinding stages.

To our surprise, even though we introduced 6MW of extra grinding power, operating cost per tonne of feed did not increase.

Based on a geometrical analysis in combination with experimental verifications,this paper deals with the mechanism of steel conditioning and the effects of grinding wheel speed vupon such factors as——the metal removal rate Zw;——the grinding wheel wear rate Zs;——the grinding ratio G and——the grinding power Pm and specific grinding energy u.An inference has been drawn from the investigation that a spheroidal surface must be formed on the grinding wheel around its axis while the wheel comes into a steady state...

Based on a geometrical analysis in combination with experimental verifications,this paper deals with the mechanism of steel conditioning and the effects of grinding wheel speed vupon such factors as——the metal removal rate Zw;——the grinding wheel wear rate Zs;——the grinding ratio G and——the grinding power Pm and specific grinding energy u.An inference has been drawn from the investigation that a spheroidal surface must be formed on the grinding wheel around its axis while the wheel comes into a steady state soon after it contacts with the ground billet. The mean undeformed chipping thickness of a single grain is expressed as followswhere Vw——billet moving speed;d——cutting depth by grinding wheel.Cg——mean number of grain's cutting edges per mm2 on the surface of grinding wheel)θ——half vertex angle of grain;J——ratio D/D', D the diameter of grinding wheel and D' the diameter of spheroidal surface formed on grinding wheel.Over 170 full-scale tests show that the change of grinding wheel speed is of great importance to steel conditioning. Increase in grinding wheel speed has the advantages of raising the productivity and grinding ratio and reducing the specific grinding energy, so that the steel conditioning cost is reduced and some technical parameters are improved. By regression analysis, test results are shown as coefficicients and exponents which are listed in tables 2,3 and 4 , and the relevant semiemperical relationships of Zw, Zs and u in certain conditions are given in formulae (13) , (14) and(16) respectively. They are probably valuable for revealing further the mechanism of steel conditioning and designing new types of conditioning machines.

In this paper,the effects of head force Fn on such conditioning parameters as metal removal rate Zw,wheel wear rate Ws, grinding power Pm and specific grinding energy u and the estimated cost C for 90° steel conditioning have been experimentally investigated. Thus, some semiempirical relationships are determined. More than 170 tests were taken and test conditions are shown in Table 2. On the basis of a geometrical grinding model of 90° conditioning established(cf. Fig. 11), the mean thickness of undeformed chips...

In this paper,the effects of head force Fn on such conditioning parameters as metal removal rate Zw,wheel wear rate Ws, grinding power Pm and specific grinding energy u and the estimated cost C for 90° steel conditioning have been experimentally investigated. Thus, some semiempirical relationships are determined. More than 170 tests were taken and test conditions are shown in Table 2. On the basis of a geometrical grinding model of 90° conditioning established(cf. Fig. 11), the mean thickness of undeformed chips ag,the maximum grinding depth d,the normal force exerting on a grain F'n, the mean length of undeformed chips l and the number of actual grinding grains in unit time No are expressed as formulas (20), (16), (17), (18) and (19) respectively.With equations as above,therefore,the steel conditioning mechanism and almost all the factors which affect the grinding process are analyzed quantitatively.It is proved theoretically that the head force Fn is quite an important parameter to steel con -ditioning.With the increase in head force Fn,the metal removal rate Zw greatly raises and, on the contrary, the specific grinding energy u greatly decreases.By means of regressive analysis to test results,as shown in Table 3 , 4 and 5 ,the conclusion may be drawn without doubt that increasing the head force Fn is an important way to effectively raise the productivity and to reduce the steel conditioning cost.

Objective.Having many influencing factors on grinding process,investigation in grinding is more complicate than that in common cutting.Quite a good deal of individual tests should be respectively performed to find out the relation between the grinding power p' and other factors in creep feed grinding and thereafter an all-sided p' analysis is made possibly.This paper suggests a new method which combines dimensional analysis with orthogonally designed test and regression analysis to study p' such that the number...

Objective.Having many influencing factors on grinding process,investigation in grinding is more complicate than that in common cutting.Quite a good deal of individual tests should be respectively performed to find out the relation between the grinding power p' and other factors in creep feed grinding and thereafter an all-sided p' analysis is made possibly.This paper suggests a new method which combines dimensional analysis with orthogonally designed test and regression analysis to study p' such that the number of tests is reduced and data processing simplified with reliability.It is favourable to more directly reveal the physical characteristics of creep feed grinding process.Through the exponential matrix analysis of variable's dimensions,a methematical model of grinding power p' along unit ground width has been derived aswhere D is the diameter of wheel,d the cutting depth by wheel,σw the binding of wheel and σb the tensile strengths of workpiece;v,vw and vd the linear velocities of wheel,of feeding workpiece and dresser respectively,n the exponents and c the constant.Experiments were designed orthogonalizably and the analyses of range and variance for experimental results are made.The analyses show that factors σw/β,vd/v and d/D have significant influences on p',while factor vw/v is of small influence on p' but great on specific grinding energy u.Applying regression analysis to experimental results,constant c and exponents n in the above formula are given asc=3.78×10-5 n1=3.38,n2=0.022,n3=0.2 and n4=0.67.Thus,by the regression equation which includes a group of dimensionless numbers n as variables,p' can be determined.As seen,the strength ratio σw/σb is of importance,of which the optimum value is to be 5 approximately.Parameters vw/v and d/D characterize the size effects and vm/v≈3.76 is better.Parameter vd/v shows the influence of dresser feeding on p'.Tab.1 Level of different factorsTab.2 L9(43) orthogonal experiment designTab.3 Calculation for L9(43) variance analysisTab.4 Variance analysisTub.5 Level codeTab.6 Regression analysisFig.1 Representation of range analysis