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Note on a laboratory apparatus to study the high speed impact between a liquid drop and a surface
498
LITERATURE
AND CURRENT
The relationship between cavitation attack and erosion of metals is discussed. Extensive references are made to existing literature on cavitation attack. Data are reported on the effect of hardness on accelerated cavitation testing of chromium stainless steels, effect of sodium dichromate inhibitors on resistance of metals to pitting, and determination of the relative erosion resistance of alloys by the vibratory method. Streamlining, good surface finish and the use of cavitation resistant materials tended to reduce the cavitation effect. The relative resistance of metals to cavitation could be evaluated successfully with a twohour magnetistrictive test. Effect of Grain Size on the Resistance of Steels to Cavitation Erosion. I. N. Bogachev and R. I. Mints. Henry Brutcher Translation No. 4317. 6 pp. (From Metallovedeniei Obrabotka Metallou, no. 8, Aug., 1958, p. 26-29.) Henry Brutcher, Altadena, Calif. in single-phase (austenitic, Relationships ferritic) steels. Mechanism of cavitational destruction. Cavitation erosion in steels with duplex structures as function of grain size, component making up the network proper, and brittleness or toughness of steel: mechanism of cavitational failure. Erosion Wear and Wear Protection of Austenitic Steels for Gas Turbine Blades (in Russian) V. I. I’rosvirinand A I. Fedosov. InzhenernoFizicheskii Zhurnal, v. L, no. I. Jan. ~959, p. 6-14 The best method of protection from erosive wear is by simultaneous saturation by C, Cr, and N, or the two latter elements, when the coefficient of resistance to erosion is increased by IO or more. The character and mechanism of erosive wear on blades is described. A Correlation between Rain Erosion of Perspex Specimens in Flight and on a Ground Rig. T. J. Methven and B. Fairhead. Royal Aircraft Establishment (Gt. Brit.) November 1958. 11 pp. diagrs., photos., tabs. (Ask for CN-71206) The amount of surface erosion on Perspex has been measured for specimens flown on an aircraft in rain and tested on a whirling arm ground rig in artificial rain. Specimens were compared at 400 knots and similar rain concentrations. Results show that I in./h rain in flight gives similar erosion to 1.5 in./h on the ground rig; this may be due to the greater range of droplet sizes found in flight. Note on a Laboratory Apparatus to Study the High Speed Impact between a Liquid Drop and a Surface. 1). C. Jenkins, J. D. Booker, and J. W. Sweed. Royal -4ircraft Establishment (Gt. Brit.) Feb-
EVENTS
VOL.
2
@958/59)
ruary 1958. IO pp., diagrs., photos., tab. (Ask for N-65562) An apparatus is described which is being used for the study of the effects of high-speed impact between a liquid drop and a surface, The apparatus has been used at speeds up to 1750 ft./set. Some other applications of the apparatus are discussed. A Preliminary Investigation of High-speed Impact: the Penetration of Small Spheres into Thick Copper Targets. A. C. Charters and G. S. Locke, Jr. NACA RM A58Bz6, May 19.58. 21 pp., diagrs., photos. Small metal spheres of various densities were fired at high speed into thick targets of copper and lead. In general, it was found that all of the penetrations could be correlated quite well for engineering purposes by a function relating the depth of penetration to the impact momentum per unit volume.
Reducing Scuffing and Wear of Ferrous Metals. Surface Treatment by Sulfinuz Process. F. D. Waterfall. Engineering, v. 187, Jan. 7.8, 1959, p. 116.120. This process is to impregnate steel or cast iron surfaces with S and N, to reduce scuffing and wear. Surfaces are treated in a molten salt bath of cyanide and S compounds at about 57o’C from 5 minutes to 8 hours. After two hoursat 5706C, a “white” microscopic surface layer about 0.0005 in. in depth can be observed. Nitrogen penetrates beyond this white layer and confers some benefit to the metal below. Severe Wear of Pea&tic Steel Weld Metal. Sukemitu Ito, Kozo Honda, and Kikuzo Ishiyama. Journal of Mechanical Laboratory of Japan, v. 4, no. I, 1958, p. rs-sr. The value indicating wear was found for 39 different brands of hardfacing electrodes. The relation between the wear property and microstructure or chemical composition was complex. The Acceleration of Pitting Failure by Water in the Lubricant. 1~. Grunberg and D. Scott. Institute of Petroleum, Journal, v. 44, Nov. 1958, p, 406-410. The effect of water content of the lubricant on the incidence of pitting type failure of ball bearings was studied using the four ball rolling test. Several oilsof different characteristics which are being used for the lubrication of ball bearings in practice were tested under four conditions of water content. The presence of water in the lubricant accelerated the pitting failure of balls made of conventional EN. 31 steel, but had no effect on the pitting failure of stainless steel balls.
LITERATURE
AND CURRENT
The relationship between cavitation attack and erosion of metals is discussed. Extensive references are made to existing literature on cavitation attack. Data are reported on the effect of hardness on accelerated cavitation testing of chromium stainless steels, effect of sodium dichromate inhibitors on resistance of metals to pitting, and determination of the relative erosion resistance of alloys by the vibratory method. Streamlining, good surface finish and the use of cavitation resistant materials tended to reduce the cavitation effect. The relative resistance of metals to cavitation could be evaluated successfully with a twohour magnetistrictive test. Effect of Grain Size on the Resistance of Steels to Cavitation Erosion. I. N. Bogachev and R. I. Mints. Henry Brutcher Translation No. 4317. 6 pp. (From Metallovedeniei Obrabotka Metallou, no. 8, Aug., 1958, p. 26-29.) Henry Brutcher, Altadena, Calif. in single-phase (austenitic, Relationships ferritic) steels. Mechanism of cavitational destruction. Cavitation erosion in steels with duplex structures as function of grain size, component making up the network proper, and brittleness or toughness of steel: mechanism of cavitational failure. Erosion Wear and Wear Protection of Austenitic Steels for Gas Turbine Blades (in Russian) V. I. I’rosvirinand A I. Fedosov. InzhenernoFizicheskii Zhurnal, v. L, no. I. Jan. ~959, p. 6-14 The best method of protection from erosive wear is by simultaneous saturation by C, Cr, and N, or the two latter elements, when the coefficient of resistance to erosion is increased by IO or more. The character and mechanism of erosive wear on blades is described. A Correlation between Rain Erosion of Perspex Specimens in Flight and on a Ground Rig. T. J. Methven and B. Fairhead. Royal Aircraft Establishment (Gt. Brit.) November 1958. 11 pp. diagrs., photos., tabs. (Ask for CN-71206) The amount of surface erosion on Perspex has been measured for specimens flown on an aircraft in rain and tested on a whirling arm ground rig in artificial rain. Specimens were compared at 400 knots and similar rain concentrations. Results show that I in./h rain in flight gives similar erosion to 1.5 in./h on the ground rig; this may be due to the greater range of droplet sizes found in flight. Note on a Laboratory Apparatus to Study the High Speed Impact between a Liquid Drop and a Surface. 1). C. Jenkins, J. D. Booker, and J. W. Sweed. Royal -4ircraft Establishment (Gt. Brit.) Feb-
EVENTS
VOL.
2
@958/59)
ruary 1958. IO pp., diagrs., photos., tab. (Ask for N-65562) An apparatus is described which is being used for the study of the effects of high-speed impact between a liquid drop and a surface, The apparatus has been used at speeds up to 1750 ft./set. Some other applications of the apparatus are discussed. A Preliminary Investigation of High-speed Impact: the Penetration of Small Spheres into Thick Copper Targets. A. C. Charters and G. S. Locke, Jr. NACA RM A58Bz6, May 19.58. 21 pp., diagrs., photos. Small metal spheres of various densities were fired at high speed into thick targets of copper and lead. In general, it was found that all of the penetrations could be correlated quite well for engineering purposes by a function relating the depth of penetration to the impact momentum per unit volume.
Reducing Scuffing and Wear of Ferrous Metals. Surface Treatment by Sulfinuz Process. F. D. Waterfall. Engineering, v. 187, Jan. 7.8, 1959, p. 116.120. This process is to impregnate steel or cast iron surfaces with S and N, to reduce scuffing and wear. Surfaces are treated in a molten salt bath of cyanide and S compounds at about 57o’C from 5 minutes to 8 hours. After two hoursat 5706C, a “white” microscopic surface layer about 0.0005 in. in depth can be observed. Nitrogen penetrates beyond this white layer and confers some benefit to the metal below. Severe Wear of Pea&tic Steel Weld Metal. Sukemitu Ito, Kozo Honda, and Kikuzo Ishiyama. Journal of Mechanical Laboratory of Japan, v. 4, no. I, 1958, p. rs-sr. The value indicating wear was found for 39 different brands of hardfacing electrodes. The relation between the wear property and microstructure or chemical composition was complex. The Acceleration of Pitting Failure by Water in the Lubricant. 1~. Grunberg and D. Scott. Institute of Petroleum, Journal, v. 44, Nov. 1958, p, 406-410. The effect of water content of the lubricant on the incidence of pitting type failure of ball bearings was studied using the four ball rolling test. Several oilsof different characteristics which are being used for the lubrication of ball bearings in practice were tested under four conditions of water content. The presence of water in the lubricant accelerated the pitting failure of balls made of conventional EN. 31 steel, but had no effect on the pitting failure of stainless steel balls.