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Cutting zone temperature in diamond grinding
as a coolant, limits softening of the chip so that more energy is required than for cutting in air. With twophase materials it acts similarly but prevents b.u.c. at low speeds. The results confirm theory but higher energies are required in practice. Five basic processes govern chip formation : shear along the shear plane, tool face drag, collar formation, builtup-edge formation and chip cracking. The current state of understanding of these processes is reviewed.
Rolling Element Fatigue and Macroresidual Stress. rt.I<.Kcpple and K. L. Mattson, JOLT, 9” SW. F, (I) (1970) 76-82; IO figs., 4 tables, 14 rcfs. An investigation to determine the effect of residual stress on rolling element fatigue life. Hoop-shaped specimens statically stressed in both a tangential and transverse direction, to simulate biaxial tension or compression stress states, were subjected to repeated rolling contact fatigue. The results showed that fatigue properties for the compressive state are not significantly better than the zero stress state which is contrary to general opinion. Tensile state was detrimental as expected. 2. SURFACE PROPERTIES, AND FRICTION
ADHESION
Interactions in Neopentyl Polyol EsterTricresvl Phosuhate-Iron Systems at 500°F. ft. L. Cottingion and H. Ravner, ASLE Trans., 12 (4) (1969) 280--286; 7 tables, IO refs. Neopentyl polyol esters are thermally stable at 500°F but in the presence of ferrous metals lubricant degradation and metal corrosion are severe. TCP stabilises the metal/ester system by generating a passive oxide on the metal surface. In the presence of water TCP accelerates ester hydrolysis. Aliphatic amines which react with TCP acidic impurities or breakdown products reduce the catalysed hydrolysis of the esters. TCP reacts with free carboxyiic acids to produce phosphoric type acids. Reaction mechanisms are postulated. Evaluation of Size of Actual Contact Area. S. V. Ventsel and V. Ya. Kryuchov, Ratssiart E+zg. /., 49 (7) (1969) 19-20; 1 table, 6 refs. (Transl. by P.E.R.,Z. of Ct. Britain of I’estn. ,Wasckinostu., 4g (7) (1969) 17-18.) h proposed method of assessing the actual contact area of friction pairs is outlined. It consists of comparing wear by weight and w.Gxw,16 (1970) 15X-163
linear wear tictcrmined by rcIcrcncc indcntation. Test results justify the use of the mtthotl in tests of average duration and at rclativcly high pressures. From the quoted numerical values obtained the contact arcas make up r._lm3.2’:; of the geometrical areas which correlates with the results of other workcr~. Cutting Zone Temperature in Diamond Grinding, _X. 31. X,‘asil’cv et nl. Ii~ssia?~ Eq. ,I., 49 (7) (1969) (ij-66; 3 figs., I table, s rcfs. (Trwsl. by- I’.T<. IZ..‘i. of Ct. Britain of 17c.sfn. iMasri~i?austr., J-y (7) (‘$xj) 51-57.) A consideration of the possibility of deriving a thcorctical equation for determining the workpiecc surface temperature in the cutting zone when grindiug with a diamond wheel. The temperature is greatly affected by wheel grit and the most important factor is grinding depth. The best wheels, as regards wear resistance and thermal intensity of the grinding process. are ceramic-bonded wheels and wheels with a bakclite-copper special arlditivc bond. Surface Quality of Electrochemically Machined Components. .-\. I. be\ rntal., Russia?z Eng. .I., 49 (7) (1969) 09-70; 2 figs. (Transl. by P.E.FC.iZ. of Ct. Britain of I’estlz. il~aschiwxtr., 49 (7) (1969) j9-61. The results of a study of the effect of various aspects of the electrochemical machining process on surface layer quahty. To achieve high-speed machining with mnnmum machined surface roughness, current density should bc maintained within a narrow specific range which varies with the different types of high-strength material machined. Stresses in the Chip Formation Zone. N. N. Zorev d al., Russian Etzp. J. 49 (7) (1969) Sr-84; 3 figs., 5 refs. (Transl. by l’.E. 1i.X. of Ct. Britain of VestvL.Muschiwstv., 49 (7) (1969) 71-74. ,I method based on hardness measurements has been used to determine the stressed state of the metal in the formation of a shear chip and in the formation of a continuous chip. Based on this method a new method is &scribed in terms of an actual application whereby the stresses can be ca.lculated by computer and the boundary conditions determined more accurately. Uptake of Phosphate Ions by Oxide Films on Mild Steel. J. C. N. Thomas, British Corrosion J., 5 (I) (1970) 41-45; 3 figs., 21 refs. By radio tracer methods, phosphate ionswere found to be firmly bonded by oxide films on mild steel after immersion in 0.1 M sodium phosphate over the pH range 7-13. hutoradiography showed that the major part of
Rolling Element Fatigue and Macroresidual Stress. rt.I<.Kcpple and K. L. Mattson, JOLT, 9” SW. F, (I) (1970) 76-82; IO figs., 4 tables, 14 rcfs. An investigation to determine the effect of residual stress on rolling element fatigue life. Hoop-shaped specimens statically stressed in both a tangential and transverse direction, to simulate biaxial tension or compression stress states, were subjected to repeated rolling contact fatigue. The results showed that fatigue properties for the compressive state are not significantly better than the zero stress state which is contrary to general opinion. Tensile state was detrimental as expected. 2. SURFACE PROPERTIES, AND FRICTION
ADHESION
Interactions in Neopentyl Polyol EsterTricresvl Phosuhate-Iron Systems at 500°F. ft. L. Cottingion and H. Ravner, ASLE Trans., 12 (4) (1969) 280--286; 7 tables, IO refs. Neopentyl polyol esters are thermally stable at 500°F but in the presence of ferrous metals lubricant degradation and metal corrosion are severe. TCP stabilises the metal/ester system by generating a passive oxide on the metal surface. In the presence of water TCP accelerates ester hydrolysis. Aliphatic amines which react with TCP acidic impurities or breakdown products reduce the catalysed hydrolysis of the esters. TCP reacts with free carboxyiic acids to produce phosphoric type acids. Reaction mechanisms are postulated. Evaluation of Size of Actual Contact Area. S. V. Ventsel and V. Ya. Kryuchov, Ratssiart E+zg. /., 49 (7) (1969) 19-20; 1 table, 6 refs. (Transl. by P.E.R.,Z. of Ct. Britain of I’estn. ,Wasckinostu., 4g (7) (1969) 17-18.) h proposed method of assessing the actual contact area of friction pairs is outlined. It consists of comparing wear by weight and w.Gxw,16 (1970) 15X-163
linear wear tictcrmined by rcIcrcncc indcntation. Test results justify the use of the mtthotl in tests of average duration and at rclativcly high pressures. From the quoted numerical values obtained the contact arcas make up r._lm3.2’:; of the geometrical areas which correlates with the results of other workcr~. Cutting Zone Temperature in Diamond Grinding, _X. 31. X,‘asil’cv et nl. Ii~ssia?~ Eq. ,I., 49 (7) (1969) (ij-66; 3 figs., I table, s rcfs. (Trwsl. by- I’.T<. IZ..‘i. of Ct. Britain of 17c.sfn. iMasri~i?austr., J-y (7) (‘$xj) 51-57.) A consideration of the possibility of deriving a thcorctical equation for determining the workpiecc surface temperature in the cutting zone when grindiug with a diamond wheel. The temperature is greatly affected by wheel grit and the most important factor is grinding depth. The best wheels, as regards wear resistance and thermal intensity of the grinding process. are ceramic-bonded wheels and wheels with a bakclite-copper special arlditivc bond. Surface Quality of Electrochemically Machined Components. .-\. I. be\ rntal., Russia?z Eng. .I., 49 (7) (1969) 09-70; 2 figs. (Transl. by P.E.FC.iZ. of Ct. Britain of I’estlz. il~aschiwxtr., 49 (7) (1969) j9-61. The results of a study of the effect of various aspects of the electrochemical machining process on surface layer quahty. To achieve high-speed machining with mnnmum machined surface roughness, current density should bc maintained within a narrow specific range which varies with the different types of high-strength material machined. Stresses in the Chip Formation Zone. N. N. Zorev d al., Russian Etzp. J. 49 (7) (1969) Sr-84; 3 figs., 5 refs. (Transl. by l’.E. 1i.X. of Ct. Britain of VestvL.Muschiwstv., 49 (7) (1969) 71-74. ,I method based on hardness measurements has been used to determine the stressed state of the metal in the formation of a shear chip and in the formation of a continuous chip. Based on this method a new method is &scribed in terms of an actual application whereby the stresses can be ca.lculated by computer and the boundary conditions determined more accurately. Uptake of Phosphate Ions by Oxide Films on Mild Steel. J. C. N. Thomas, British Corrosion J., 5 (I) (1970) 41-45; 3 figs., 21 refs. By radio tracer methods, phosphate ionswere found to be firmly bonded by oxide films on mild steel after immersion in 0.1 M sodium phosphate over the pH range 7-13. hutoradiography showed that the major part of