Cast Iron Disc Research Articles

Friction and Wear of α-Sialon Ceramics

The friction and wear properties of newly developed partially stabilized α-sialon ceramics were measured with a pin-on-disk type tester in air at room temperature, at a sliding velocity of 18cm/s and applied load of 1kgf. When α-sialon disk was used, the specific wear rate of α-sialon was 4×10-8mm2/kgf, a little greater than Si3N4 or ZrO2. The wear of α-sialon on ZrO2 disk was in the same level as that on α-sialon disk, but the wear of Si3N4 and ZrO2 on ZrO2 disk was much higher. α-sialon is considered to be one of the excellent wear resistant materials, as it shows relatively low specific wear rate, and α-sialon disk wears much less than ZrO2 disk. The wear of α-sialon was almost zero, when sliding on metal disks, such as cast iron or phosphorus bronze, which is the same as any other ceramics. On the other hand, the wear of metal disk was severe, with the specific wear rate in the order of 10-5mm2/kgf. Cast iron disk showed two times greater wear than phosporus bronze disk against the α-sialon pin.

Friction Viewed as a Random Process

A stationary cast-iron button sliding against a rotating cast-iron disk generated a time-varying friction signal. The signal was recorded using digital computer data-acquisition techniques. Sixty runs were taken, using different values for various parameters (such as load, velocity, and temperature). The data were analyzed on a digital computer by two different techniques. The first was a time-series analysis: the Fourier transform of each run was taken and the power spectral density of the run was studied. The second technique was a standard statistical analysis using the Kolmogorov-Smirnov goodness-of-fit test. From the two analyses, some interesting conclusions were made: 1 – the friction behaves like a random process, 2 – friction may be treated as a constant signal with superimposed white noise, 3 – the instantaneous coefficient of friction is normally distributed, 4 – friction is influenced by load and velocity, and 5 – the mean value and standard deviation are functionally related.

Corrosive and erosive wear of metals in mineral slurries

A laboratory study was made of the effect of corrosion control methods on the metal losses of.mild steel, white cast -iron, Ni-hard cast iron, stainless steel and Cr-plated steel discs that were ro...

Fundamental studies on the brake friction of resin-based friction materials

The effects of various factors on brake friction were studied on the braking of a cast iron disk by small brake specimens made of resin, resin-asbestos composites and three-component composites. When the disk temperature rises, the resin-based composites containing asbestos and high melting point additive exhibit considerably lower friction during braking following high friction in the initial braking stage. The initial high friction is attributed to the deformation resistance of the resin in the composite. Low friction is attributed to the lubricating action of resin decomposition products in the neighbourhood of the filler raised to a high temperature by frictional heating. Increase of friction toward the end of braking is mainly due to increase of the true contact area as the frictional speed decreases. Variation of the average frictional coefficient during braking with load and the initial speed is generally small. There is no correlation between the mechanical properties and the brake frictional behaviour of resin-based composites.

The application of neutron activation analysis to the measurement of the wear of a friction material

Automobile braking has been simulated by pressing a resin-asbestos material against a mating cast-iron disc to give constant deceleration. The wear dust, in milligram quantities, has been collected by air filtration and analyzed by neutron activation analysis. Each component of the friction material has been identified in the wear dust together with the iron from the disc. It has been shown that there is no preferential wear of the components of the friction material, that the wear of the disc is some 40% by weight of that of the friction material and that the wear of both friction material and the disc obey a modified form of Archard's wear law over a range of operating temperatures.

The application of moiré rotational mismatch techniques to strain analysis

Theoretical and technological aspects of moiré fringe techniques when applied to problems of strain analysis are discussed. An outline is given of the methods of determination of direct and shear strain distributions of elastic and plastic orders of magnitude from the formation of moiré patterns resulting from the superposition of two gratings of straight parallel lines. The rotational mismatch technique is discussed and shown to give strain directly. Reference is made to the use of master gratings, to the ‘photo-resist’ and ‘stripping film’ techniques for the reproduction of these gratings and to some of the photographic difficulties encountered. The advantages of the moiré techniques over conventional methods of strain evaluation employing extensometers, strain gauges and photoelastic materials are discussed and illustrated by results obtained during (1) uni-axial tensile tests on mild steel, brass and aluminium alloy, and (2) diametral compressive tests on cast iron discs.

Paper 2: Adhesion in Railway Braking

Reasons are advanced why the processes of adhesion in braking may differ from those in traction, and limitations of adhesion-measuring machines are discussed. It is shown how the nature of the variation of braking torque with velocity may affect the driver's manner of applying the brakes. Incidence of pick-up from 2000 brake applications on three different types of brake (cast-iron tread, non-metallic tread, and disc) are studied to investigate the effect of load, the effect of moisture, and the effect of speed on adhesion. The incidence of pick-up is found to be less for a loaded than for an empty train and greater for wet than for dry rails, so confirming known facts and justifying the particular method of approach. A complex adhesion/speed characteristic with a minimum value in the range 40–50 miles/h for dry tare conditions is shown to exist, which demonstrates that relations generally accepted to be applicable to braking are invalid. On wet rails incidence of pick-up is higher on the leading bogie and the suggestion is made that brake forces to this bogie could be reduced. Off-tread braking increases vulnerability to wheel sliding but with wheel-slide protection the exacting demands of dense suburban traffic are adequately met.

On Fluid Friction of Rotational Rough Disc in Rough Vessel

Though numerous studies of disc friction of smooth surface were already carried out, but the detail discussions of disc friction of rough surface have not yet been performed. Experiments were carried out for both cases of discs with smooth surface and rough surface, consisting of sand-grain of various size and shape. The main results obtained may be sumarized as follows : 1) Resistance Coefficient Cf in turbulent flow region tends to a certain value with increasing Re for rough surface. 2) For a certain small value of clearance, coefficient Cf takes a minimum value. 3) Resisting moment of cast-iron disc is equal to that of the disc with rough surface IV. 4) When geometrical similarity is held for the dimension of apparatus, Cf depends on Re only. 5) For increment value of resistance coefficient induced by roughness, the relations Cf1≒2Cf2≒4Cf3 hold.

The Adhesion Theory of Friction

It is shown that the static friction between a specimen of bituminous material and a cast iron disc is due to adhesion between specimen and disc, and that the friction is reduced when the normal load is removed because of elastic interaction between the surfaces.

On Fluild Friction of Rough Disc

Though numerous studies of disc friction of smooth surface were already carried out, but the detail discussions of disc friction of rough surface have not still been performed. Experiments were carried out for both cases of discs with smooth surface, and rough surface consisting of sand-grain of various size and shape. The main results obtained may be sumarized as follows : 1) For a certain value of clearance, the resistance coefficient takes a minimum value. 2) Resistance moment of cast-iron disc is equal to that of the roughness IV surface of disc (average dia. of sand-grain is 0.04 mm). 3) Let Cf1, Cf2 and Cf3 be the increment value of resistance coefficient of a rough disc in rough vessel, rough disc in smooth vessel and smooth disc in rough vessel, respectively, we obtain the following relation, C ≒2 C ≒4 Cf3, where the increment value means the increase to resistance coefficient of smoth disc in smooth vessel.

The effect of lubrication on friction, wear and abrasion

The lubrication of a grinding surface is one of the most important items in abrasive processes, and experimental work on it is reported. Recent tests, in which the coefficient of friction was measured by an electronic dynamometer, employed a cast-iron disk in contact with a lubricated diamond surface. Using various oils, the coefficient of friction was generally below 0.08 without diamond powder and about 0.11 with the powder.

The Iron Wharf At Fort Monroe, Va.

General Description. The iron wharf at Fort Monroe, Va., was built in 1888-89, in accordance with the provisions of Acts of Congress approved August 4th, 1886, and August 10th, 1888. The wharf is located on the site of an old wooden wharf formerly known as the “Baltimore Wharf,” and at the terminus of the roadway passing in front of the Hygeia Hotel. The general plan of the wharf is shown on Plate XXII, Fig. 1. It is built on hollow cylindrical cast-iron disc and screw piles (the latter having wooden bearing piles), spaced 14 feet apart from center to center in each direction, and braced by two systems of horizontal bracing of steel and wrought iron.

Leverich on Strains in Cast-Iron Disk

Leverich on Strains in Cast-Iron Disk