Abstract: Method for manufacturing a tube of metal in which sensors are attached to tubes, which register and signal a damage of the tube. It is detrimental that protection of the sensors at these tubes against environmental influences is complex. In contrast, it is an object of the present disclosure to provide a method for manufacturing a tube, in which the signal line can be protectively mounted. To solve this object, a method for manufacturing a tube of metal is suggested with an outer tube and an inner tube, wherein a groove is drawn in an inner surface of the outer tube or in an outer surface of the inner tube and subsequently the inner tube and the outer tube are drawn together through a drawing die, wherein the inner dimension of the outer tube is reduced such that after the drawing the outer tube is force-fitted onto the inner tube.

Abstract: A drill string and a threaded coupling region for a drill string include threaded male and female ends that are optimized to maximize energy transmission efficiency for percussion drilling. The coupling includes a male spigot to be received within a female sleeve, such that an axial length of the overlap of the spigot within the sleeve is less than an outside diameter of the sleeve.

Abstract: Method for manufacturing a tube of metal in which sensors are attached to tubes, which register and signal a damage of the tube. It is detrimental that protection of the sensors at these tubes against environmental influences is complex. In contrast, it is an object of the present disclosure to provide a method for manufacturing a tube, in which the signal line can be protectively mounted. To solve this object, a method for manufacturing a tube of metal is suggested with an outer tube and an inner tube, wherein a groove is drawn in an inner surface of the outer tube or in an outer surface of the inner tube and subsequently the inner tube and the outer tube are drawn together through a drawing die, wherein the inner dimension of the outer tube is reduced such that after the drawing the outer tube is force-fitted onto the inner tube.

Abstract: A drill string and a threaded coupling region for a drill string in which a threaded male and female end are optimised to maximise energy transmission efficiency for percussion drilling. The present coupling includes a male spigot to be received within a female sleeve such that an axial length of the overlap of the spigot within the sleeve is less than an outside diameter of the sleeve.

Abstract: An austenitic Ni-based alloy with improved workability, good corrosion resistance and good structure stability useful as heat exchanger tubing in sulphur-, chloride- or alkaline-containing environments. The material has an austenitic structure which contains in weight-% up to 0.025% C, 20-27% Cr, 8-12% Mo, up to 0.5% Si, up to 0.5% Mn, up to 0.3% Al, up to 0.1% N, 3-15% Fe, up to 0.5% Ti, up to 0.5% Nb, the remainder being Ni and usual impurities.

Abstract: A new austenitic stainless steel comprising in % by weight:C: <0.12,Si: <1.0,Cr: 16-22,Mn: <2.0,Ni: 8-14,Mo: <1.0,either Ti: >4% by weight of C and <0.8 or Nb: 8% by weight of C and <1.0,S: <0.03,O: <0.03,N: <0.05,REM: .ltoreq.0.30 and >0.10, and the remainder Fe and normally occurring impurities, REM being one or more of the elements Ce, La, Pr and Nd. The new steel is particularly suitable as a superheater steel and a heat exchanger steel.

Abstract: A composite tube with improved resistance to thermal fatigue and stress corrosion for use in soda recovery units comprising an inner tubing of a conventional carbon steel and an outer liner of a Cr--Ni--Mo--Fe-based alloy with austenitic structure which alloy contains, in weight-%, 0.01-0.04 C, 19.5-23.5 Cr, 38-46 Ni, 2.5-3.5 Mo, up to 0.5 Si, up to 0.3N, and the remainder being Fe, except normal impurities.