Abstract: A method and apparatus for manufacturing a plug-type chamber to accommodate at least two floating plugs for use in the cascade drawing of tubes is disclosed. A starting tube is first fixed in position by a clamping and denting device. A necking-down ring is subsequently moved with the help of a necking-down cylinder along a freely projecting end section of the starting tube. A punch is then pushed with the help of a cylinder into the end section of the tube. When the punch has reached its end position, the necking-down ring is pulled over the end section of the tube, and the outside diameter is reduced to its original size. The punch is subsequently removed, and two indentations are made on the periphery of the end section of the starting tube with the help of the clamping and denting device.

Abstract: In a process for the production of tubular bodies that are resistant to stress corrosion cracking, in particular non-magnetizable drill stems and rod sections of austenitic steels, after solution treatment, quenching, and after deformation at a temperature of under 500.degree. C., in order to increase the mechanical properties of the material, and after processing and incorporation of a drilling, the body is heated to a temperature of 220.degree. to 600.degree. C., at least to temperature equalization with a temperature differential of at most 10.degree. C. in the walls of the body. The body is then maintained for at most a time t in minutes at a temperature T in degrees Celsius in accordance with the expressiont=10.sup.-(T-638)/50after which it is cooled by the increased withdrawal of thermal energy, at least from the internal surface of the tubular body and the cooled surface exhibits a temperature drop of at least 100.degree. C.

Abstract: The method of manufacturing nonmagnetic drilling string components, especially heavy duty drill-stems for exploratory bores, e.g. for deposits of crude oil and/or natural gas deposits, such as directional bores or the like, includes the step of melting and allowing to solidify an alloy consisting essentially of, each in percent by weight:carbon in a maximum of 0.15, preferably 0.08;silicon in a maximum of 1.0;manganese 11.0 to 25.0, preferably 12.0 to 20.0;chromium 10.0 to 20.0, preferably 11.0 to 16.0;molybdenum 0.1 to 1.0, preferably 0.2 to 0.8;nickel 0.1 to 6.0, preferably 1.0 to 3.0;nitrogen 0.05 to 0.5, preferably 0.1 to 0.35; andthe remainder being iron and impurities resulting from manufacturing conditions. The alloy is subjected to an at least two-stage, especially a four- to six-stage hot-working process and, if desired, cooled down and then solution heat-treated at about 1,020.degree. C. to about 1,070.degree. C.