Mannesmann Aktiengesellschaft

Kurt Roether

Heinz O Schumacher

Gerhard Krug

Gerhard Missaire

Herbert Hillemanns

Hans Ribken

Wolfgang Hellmund

Hermann Vollmecke

Paul Schatton

Wilfried Carneim

A method of making tubing and pipes for conduction in the oil and gas industry or for use as drillpipes, wherein such tubing is connected at both ends with connector sleeves by means of welding, the welding seam being deburred thereafter. The steel used for the tubing, pipes or drill pipes as well as for the connector sleeves has the following composition, all percentages by weight, between 0.2 and 0.6% carbon, between 0.5 and 1.8% manganese, between 0.5 and 3.5% combined chromium and molybdenum, not more than 0.2% phosphorus and not more than 0.005% sulphur. The combined unit of tubing and two welded on connectors is heated to a temperature which is at least 50 but not more than 200 degrees Centigrade above AC3; quenched from this temperature down to a temperature of at least 200 degrees Centigrade below AR1, tempered at a temperature below AC1, and cooled in non-moving air, to obtain the following properties: yield strength between 515 to 760 N/square mm, tensile strength at least 660 N/square mm, elongation at least 15.5%, hardness not more than 26 HRC, impact notch ductility at room temperature in accordance with ISOV of at least 60 Joules, long duration strength tested for more than 720 hours in accordance with NACE-TM-01-77 in a hydrogen sulphide saturated test solution at a load of not less than 80% of said minimum yield strength.

Method of making tubular units for the oil and gas industry

Hot pipes are tempered in an oil bath contained in a tapered, covered pan; a flap is temporarily opened for feeding, but closed when oil vapor develops, to be sucked off without contaminating the environment. Pan and cover structure are supplemented to prevent uncontrolled escape of vapor during treatment. Different handling devices for pipes in the interior of the pan are described.

Oil-tempering apparatus for pipes

A box member and a pin member each have a tapered thread, an abutment end face and a shoulder for engagement respectively with shoulder and end face of the other member, one coacting surface pair being conical, the other one being planar. Shoulder and end face are spaced differently in the two members such that upon engagement of a conical shoulder and end face, planar end face and shoulder have a gap of about 0.5 to 2.5 per cent of the spacing. Taper/bulge seals are provided adjacent the abutment surfaces to be effective before the planar surfaces abut as the joint is made up. The effective pitch diameter of the pin member remains consistently smaller than the pitch diameter of the box member, at least up to an insertion of the pin member so that the planar surfaces abut.

Casing joint

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Dusseldorf, Germany

Kurt Roether