Abstract: Cast iron with a vermicular graphite structure is produced by a process which involves the steps of determining the ratio of magnesium to sulphur in the melt and then adjusting the value of such ratio to between about 0.8 and 2.5.

Abstract: In a molding machine for producing foundry sand molds the sand is compressed or packed by means of a pressure wave acting on the sand surface produced by explosive combustion of a mixture of fuel and air. The dosing of the fuel to be burned is carried out by a pressure regulated supply pipe, in which a dosing container is filled with fuel, e.g., gas, up to an exactly defined excess pressure. This fuel or gas is thereafter fed to the combustion chamber under relief of the gas pressure in the dosing container down to a lower pressure level.

Abstract: Replaceable T-head bolt for attaching a wheel rim to a wheel body are mounted in the body with the head positioned in a U-shaped recess having side surfaces and a bottom wall through which the bolt shaft extends. A washer on the bolt is held by a cotter pin passing through a hole in the bolt which is angularly offset from the long dimension of the T head. The washer is positioned by shoulders on the outside of the bottom wall, the shoulders having different heights. An L-shaped slot permits lateral insertion of the bolt head after which it is rotated 90.degree..

Abstract: A welding sleeve useable for connecting of pipes formed from thermoplastic material, is formed from a tubular body of thermoplastic material and a coil disposed on its inside surface. The coil has a resistance wire encased with thermoplastic material. The windings of the coil (4) are bonded into a compact coil which is inserted into the heated tubular body while it is simultaneously widened. As the result of a partial contraction of the tubular body also of the coil a firm connection develops between the oil and the body. Furthermore, the tubular body has a frozen-in, latent, radial contraction strain as a result of the widening, which during heating during the welding process, eliminates the radial play between coil and the pipes and produces a welding pressure.

Abstract: A feed system for machine tools in which rapidly changing cutting forces occur in milling machines with an hydraulic piston drive, a position control system and a carriage supporting either the tool or the workpiece for relative movement. The carriage is movably mounted on guides with preloadable bearings shiftably or swivelably. Dry-running friction bearings on the carriage are equipped with an automatically readjusting pressure arrangement, by means of which an adjustable shifting resistance is generated, which corresponds at least to the magnitude of the cutting force occurring. Preferably, the pressure arrangement consists of a pressure piston which may be acted upon by means of an adjustable pressure. In the case of the use of post guides, the bearings are equipped with three slide surfaces mutually displaced by 120.degree. and the pressure piston acts radially on one of the three slide surfaces.