Abstract: A nozzle for gas shielded arc welding having a support ring to be mounted on a welding torch, a cylindrical nozzle member to be mounted on the support ring and a holddown ring for securing the nozzle member to the support ring. The nozzle member is formed of a heat-resistant non-conductive material so that spatters seldom adhere to the nozzle member. The nozzle member is fixed by being pressed against the support ring, which structure facilitates the manufacture of the nozzle member. This is useful especially as a nozzle for CO.sub.2 arc welding.

Abstract: A corrosion-resistant pipe coupling made of carbon steel has on its inner surface an intermediate annular projection directed radially inward. At least an innermost part of the annular projection is formed of corrosion-resistant material such as stainless steel. The annular projection may be covered by a corrosion-resistant annular member which is secured by friction welding, electron beam welding, an adhesive or mechanical engagement. The annular member prevents corrosion of the coupling by corrosive fluids flowing in pipes.

Abstract: In order to produce a double-wall composite metal pipe, a pipe assembly, made up of an outer pipe of carbon steel and an inner pipe of stainless steel inserted in the outer pipe with an annular clearance therebetween is caused to advance relative to a plastic working device such as die or a series of rollers. Before the pipe assembly is caused to pass through the plastic working device, the outer pipe is heated to cause it to expand thereby increasing the annular clearance between the inner and outer pipes and establishing a temperature difference between the outer and inner pipes. The heated outer pipe is constricted by device of the plastic working means and caused to plastically contract against the outer surface of the inner pipe, while the inner pipe is subjected to expanding force of a mandrel inserted in the inner pipe, the mandrel backing up the pipe assembly from within the inner pipe against the constricting action of the plastic working device.

Abstract: A multiple-wall pipe structure having at least two pipes tightly fitted one within another, one of which is of a corrosion-resistant material whereas the other is of a noncorrosion-resistant material. In order to protect against corrosion the end faces of the noncorrosion-resistant pipe and the seams between the two pipes, either during storage in the form of discrete pipe sections or in use by being welded or otherwise jointed end to end, a pair of anticorrosion rings of a corrosion-resistant material are integrally attached to the opposite ends of the fitted pipes so as to cover at least the end faces of the noncorrosion-resistant pipe and to seal the seams therebetween.

Abstract: A corrosion-resistant pipe coupling made of carbon steel has on its inner surface an intermediate annular projection directed radially inward. At least an innermost part of the annular projection is formed or corrosion-resistant material such as stainless steel. The annular projection is covered by a corrosion-resistant annular member or which is secured by friction welding, electron beam welding, an adhesive or mechanical engagement. The annular member prevents corrosion of the coupling by corrosive fluids flowing in pipes.

Abstract: A double-wall composite pipe is produced by inserting an inner pipe in an outer pipe, filling the inner pipe with cold water under pressure to cause the inner pipe to expand plastically into tight contact with the outer pipe, applying heat to the outer part of the outer pipe by high-frequency induction heating, thereby to establish a locally heated zone thereof around the circumference thereof and causing the heated zone to travel from one end to the other end of the outer pipe thereby to cause it to successively expand locally in diameter in the travelling heated zone. The pressure in the inner pipe then is removed, the pipes thereafter being permitted to attain the ambient temperature, thereby to obtain an interference fit therebetween.

Abstract: A vacuum shield device of an electron beam welding apparatus including a plate of a rectangular shape formed with a slit for allowing a beam of electrons to pass therethrough, a box-shaped member secured to the undersurface of the rectangular plate with its walls surrounding the slit, and a shield member secured to the outer periphery of the lower portions of the walls of the box-shaped member. The shield member includes a base formed of a heat-resisting and flexible material maintained in pressing engagement with the upper surface of the workpiece by pressing means. The force with which the pressing means forces the base against the workpiece is adjusted by pressure control means. The box-shaped member is formed with a cutout at the lower portion of either end wall.

Abstract: An outer pipe is diametrically expanded by heating and an inner pipe is diametrically contracted by cooling with a coolant introduced into the inner pipe to produce between the pipes a clearance just sufficient for insertion of the inner pipe into the outer pipe, and then the coolant is pressurized to expand the inner pipe against and together with the outer pipe, the pressure being removed after the pipes have expanded to a specific diameter of the joint therebetween. The tightness of the fit between the pipes due to the expansion is further increased by the subsequent thermal shrinkage of the outer pipe and thermal expansion of the inner pipe.

Abstract: The rotational speed of a screw propeller mounted on a propeller shaft of a ship is correctively increased or decreased by locally heating the back or face side of each blade of the propeller along a plurality of paths substantially parallel to and inward from the trailing edge of the blade in a region from a radial position about of 0.5 R to the blade tip, where R is the tip radius, particularly from 0.6 to 0.7 R, and cooling the parts thus locally heated thereby to form wash-back in each blade between the trailing edge and the heating paths thereof as a result of angular deformation accompanying plastic deformation due to the heating and cooling and thereby to decrease or increase the effective pitch of the propeller.

Abstract: A panel structure is fabricated by stretching a skin plate with a tensile stress below the elastic limit stress thereof, securing this plate onto a framework with the plate under a constraining tensile stress and with portions thereof to which the constraining stress is not being fully applied being heated thereby to cause thermal expansion thereof, removing the constraining stress, and permitting the plate to cool and thereby to undergo thermal contraction and deformation, thereby producing tensile residual stress within the plate, whereby occurrence of welding deformations in the plate on the finished panel is prevented. Depending on the necessity, the skin plate may be prestretched with a stress exceeding the yield point thereof before the above described panel fabrication.