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At the same time, the normal force will deform both objects, just as with the static situation. If the normal force is low, the ball will rub against the plate but not permanently alter its surface. The rubbing action will create friction and heat, but it will not leave a mark on the plate.
Once the equipment is machined and returned to use, the parent metal is always significantly weaker. Often, the site of the original repair then subsequently fails. The metal stitching repair process however tends to maintain alignment of original surfaces, since the lack of heat during the repair produces no distortion of the completed repair.
Flame cleaning, also known as flame gouging, [1] is the process of cleaning a structural steel surface by passing an intensely hot oxyacetylene flame over it. Mill scale and rust are removed by the reducing effect of the flame and the action of the heat, leaving the surface in a condition suitable for wire brushing and painting.
Apotropaic marks, also called 'witch marks' or 'anti-witch marks' in Europe, are symbols or patterns scratched on the walls, beams and thresholds of buildings to protect them from witchcraft or evil spirits. They have many forms; in Britain they are often flower-like patterns of overlapping circles. [25] such as hexafoils.
Blowhole defect in a cast iron part. Tiny gas bubbles are called porosities, but larger gas bubbles are called blowholes [14] or blisters. Such defects can be caused by air entrained in the melt, steam or smoke from the casting sand, or other gasses from the melt or mould. (Vacuum holes caused by metal shrinkage (see above) may also be loosely ...
The branding iron consisted of an iron rod with a simple symbol or mark which was heated in a fire. After the branding iron turned red-hot, the cowhand pressed the branding iron against the hide of the cow. The unique brand meant that cattle owned by multiple owners could then graze freely together on the commons or open range.
A tie plate, baseplate or sole plate is a steel plate for centering and reinforcing the attachment point on the rail tracks between a flanged T rail and a railroad tie. The tie plate increases bearing area and holds the rail to correct gauge. It is fastened to wooden ties by means of spikes or bolts through holes in the plate.
The UK marks are called 'fire insurance plaques'. The first to use the mark was the Sun Fire Office which was established in 1710. [2] Some period specimens remain on historical buildings in the older areas of Britain's and America's cities and larger towns. Cast metal plaques were made of iron, lead, or sometimes brass.