Relation between Surface Appearance and Coefficient of Friction in Compressive Deformation of Metals

The compression test was performed on aluminium, copper, mild steel, stainless steel and aluminium single crystal by using various lubricants. The following results were obtained from the relationship between the microscope pattern of the compressed surface and the frictional coefficient : (1) The surface pattern of the plate after rolling is similar to that of the specimen after compression. (2) In the case of a large frictional coefficient, a glossy surface appears in the specimen in which a greater part of the surface is in contact with tools. In the case of a small frictional coefficient, a dull face having a rugged surface of a few microns in depth appears. It seems likely that there is a fluid film in the sinks. (3) In the 60% deformation of the various materials by using palm oil as a lubricant, the ratio of the surface covered by the fluid film to the total friction surface is 75～85% for aluminium or copper and about 10% for stainless steel. (4) From the compression test it is conceivable that there are deformation bands in the rugged surface of the dull face, which the lubricants fill. This phenomenon may be one of the great differences between the sliding friction and the compression deformation

Studies on Cladding

Two kinds of light metal having different flow resistance were bonded by hot-rolling, hot-extrusion and cold-rolling. In the case of cladding by cold-rolling, the combination of titanium and aluminium alloy (24S) were bonded for the investigation of some defects such as ripple and crack. The satisfactory conditions were obtained under which the bonding without defects could be made

Cold Rolling and Annealing Texture of 1% Carbon Steel

1% carbon steel was cold-rolled to 50～98.4% reduction by adhering ductile materials to the sheet edges. Globular cementite particles (Fe_3C) were formed on annealing the cold-rolled sheet below A_1 point. The effect of these particles on the annealing process and texture was studied. The results obtained are summarized as follows : (1) The cold rolling texture consists of three preferred orientations, (001) [110], (112) [110] and (111) [211], as in the case of iron and low carbon steels, but with increasing reduction. (111) [211] component disappears, while (001) [110] and (112) [110] components become dominant. (2) The mean inter-spacing of Fe_3C particles is smaller than the critical size of the recrystallization nuclei at the annealing 700℃×10 hr and becomes nearly equal to at 700℃×hr, that is, the nucleation of recrystallization is remarkably retarded by Fe_3C particles. (3) Even after a prolonged annealing (700℃×100 hr), the annealing textures are similar to the rolling texture, but at 98.4% reduction the (112) [110] component which has a higher growing rate of its subgrains than that of (001) [110] component becomes very dominant. From these results the recrystallization mechanisms are discussed

Bowing of Cold-rolled Strips by Multi-slitting

The relation between the cross sectional configurations of cold-rolled thin strips and the diameters of bowed strips after slitting has been investigated. When a cold-rolled strip is multi-slitted, an edge-rippled of a center-buckled strip will bow in its plane by the widthwise variation both in elastic strain and in plastic strain. The diameters of bowing due to both effects can be calculated by the equations (6), (11) in edge-rippled strips, and (10), (12) in center-buckeld strips respectively. These results have been ascertained by the slitting experiment of some cold-rolled strips

Effect of Lubricants on Compressive Deformation

The compression test was carried out with aluminium, copper, mild steel and stainless steel at 100, 200, 300, 400℃ and room temperature by making use of various kinds of lubricant. The results obtained are as follows : (1) It is necessary to take account of the elastic strain of the testing machine for the calculation of the friction coefficient from the load-strain curve of the compression testing. (2) In comparing both friction coefficients of rolling and of compression with each other, there is a tendency that the rolling shows a smaller friction coefficient than in the compression. This is considered to be due to the difference in the amount of friction length. (3) In the compression test with the mineral oils of various viscosities, the friction coefficient decreases with a slight increase of viscosity in the case of the viscosity below 100 Redwood sec at 50℃. However, at the viscosity above 100 Red Wood sec at 50℃, it is little changed by the variety of viscosity. (4) The order of lubricating effects is variant with the variety of lubricants, but the palm oil or beef-tallow oil shows a lower friction coefficient at room temperature and paste oil containing MoS_2, stearic acid sopa or paraffine chrolide shows good lubricating effects at high temperatures

On the Embrittlement and Toughness of High Purity Fe-30Cr-2Mo Alloy

Experiments were conducted to explain unexpected embrittlement phenomena encountered in fabricating a high purity Fe-30Cr-2Mo alloy. By means of a hydrostatic tensile test with a Bridgman-Type specimen it was found that the fracture behaviour of the alloy is highly dependent on stress state. Under conditions of low triaxial stress, the alloy displays excellent ductility. Under conditions of high triaxial stress, however, the alloy shows less strain to fracture and a transition from ductile to cleavage fracture. The toughness of the Fe-30Cr-2Mo alloy can be significantly improved by thermomechanical processing

Cold Rolling Texture of Heavy Rolled 50 Pct Ni-Fe Thin Sheets

In order to clarify the cold rolling texture of heavy rolled ultra-thin sheets of 50 pct Ni-Fe alloy, the effect of extremely high reduction and final thickness of sheets on the texture and the variation of textures through the thickness have been investigated. It has been recognized that the rolling textures of this alloy indicate to be copper-type up to this time. However, it could not be simply described as copper-type and show the peculiar textures under such an extreme rolling condition. The results obtained are summarized as follows : (1) The center textures up to 99.4 pct reduction and in the thicker sheets than 20 μ in thickness show the sharp copper-type. (2) After much higher reduction than 99.4 pct, {110} component decreases and (112) component increases and such tendency is more remarkable in thinner sheets and the surface layer. (3) After much higher reduction than 99.9 pct, weak {110} and {110} component increase slowly with increase of reduction and is stronger in the surface layer. (4) Very weak {100} component exists in deformed matrix, but after heavy reduction more than 99.4 pct and in thinner sheets than 20 μ, this component decreases still more. (5) The integrated intensity of {100} in deformed matrix corresponds to numbers of {100} in the recrystallized nuclei. From the above results the mechanisms of texture formation in ultra-thin sheets are discussed

Study on the Rolling of Metals and Alloys with Sendzimir Reversing Cold Strip Mill. I : Pattern of Waves Appearing on the Metal Foils

In the rolling of metal foils with Sendzimir reversing cold strip mill of ZR 32-4 type, the regularly spaced waves inclining to the rolling direction were sometimes observed on the foil surface. The occurrence of the waves was dependent on the front tension, but not essentially on the back tension. These waves were thought to be a kind of the center buckling of strip, but not to be the stretcher strains produced in aluminium alloys and mild steels, nor to be the herring-bone markings observed in copper alloys

Rolling-Texture Development in Aluminium Single Crystals with Deformation-Banding Tendency

Orientation changes of aluminium single crystals with a deformation-banding tendency were studied to get information about the influence of band formation on the rolling-texture development in fcc metals. Both (111)[110] and (112)[110] crystals split into two components which rotate in opposite directions about the [111] axis near the transverse direction, and they develop pairs of orientations {123} and {011} , respectively. The (111)[110]?15° crystal in which the rolling direction deviates 15° from [110] also rotates about the same axis as the formers. The end texture is, however, composed of two irrational components. Besides, pole intensity for one component is higher than the other. The dominant component is in the range of orientational spread for polycrystalline aluminium, but the poles of the minor component deviate from the intensity maxima. On the other hand, it is confirmed that the (011)[111] crystal tends to rotate in both directions about the [111] axis parallel to the rolling direction. The orientations within the range between {111} and {112} would rotate about the [111] axis near the transverse direction as in the case of (111)[110], resulting in the formation of a limited fiber texture ranging from {123} to (011) . Band formation in the orientations near {011} would build up a limited fiber texture ranging from {112} to {123}. Both the fiber textures characterize the copper-type rolling texture. The analysis of slip rotations in which the compatibility of strains is taken into consideration also indicates the development of the copper-type rolling texture. Therefore, it is concluded that all fcc metals tend to form the copper-type rolling texture