A novel copper and steel composite pipe, a manufacturing method, application and a welded structure body is described herein. The novel copper and steel composite pipe includes a copper pipe and a steel pipe. The steel pipe includes a first end, a second end and a middle part. The copper pipe includes a first end and a second end. The length of the copper pipe is less than that of the steel pipe. The copper pipe and the steel pipe are sleeved. The distance from an end surface of the first end of the copper pipe to an end surface of the first end of the steel pipe is less than 10 mm. The second end of the copper pipe is positioned at the middle part of the steel pipe, and the copper pipe and the steel pipe are welded and connected in a way of melting base materials.

Embodiments of a welding power supply including a main power supply and a background power supply are provided. The main power supply includes a first transformer that supplies a first power output to welding electrodes for use in a welding operation. The background power supply includes a secondary transformer that charges an energy storage device to a regulated voltage level and is adapted to discharge the energy storage device by a controlled amount to supply a second regulated power output to the welding electrodes for use in the welding operation when a transient voltage event occurs.

A method of joining dissimilar materials that may include a first part made of cast iron and a second part made of a metal alloy that is not made of cast iron. An insert material may be disposed between the first part and the second part. The insert material may be heated such that at least a portion of the insert material forms a transient phase liquid and bonds to the first part and the second part.

A method of joining dissimilar materials that may include a first part made of cast iron and a second part made of a metal alloy that is not made of cast iron. An insert material may be disposed between the first part and the second part. The insert material may be heated such that at least a portion of the insert material forms a transient phase liquid and bonds to the first part and the second part.

A pair of upper and lower pressure rollers 3, 4 is disposed so that their axes 15, 16 are tilted in a horizontal plane in respective directions opposite to each other with respect to a straight line perpendicular to a welding line of a joint portion J. The pressure rollers 3, 4 are positively driven by corresponding electric motors 63, 64 to thereby roll the joint portion. Thus, steps defined at the joint portion can be smoothed and a step gradient can be reduced to ensure a high degree of joint strength. Thus, it is possible to prevent a step portion from being interfolded into the base material of the meal plates 5, 6.

A pair of upper and lower pressure rollers 3, 4 is disposed so that their axes 15, 16 are tilted in a horizontal plane in respective directions opposite to each other with respect to a straight line perpendicular to a welding line of a joint portion J. The pressure rollers 3, 4 are positively driven by corresponding electric motors 63, 64 to thereby roll the joint portion. Thus, steps defined at the joint portion can be smoothed and a step gradient can be reduced to ensure a high degree of joint strength. Thus, it is possible to prevent a step portion from being interfolded into the base material of the meal plates 5, 6.

A welding head for welding the extremities of two sections of rail and comprises two half-heads (10) aligned and sliding with regard to one another in a longitudinal direction. Each half-head comprises grip mechanism (12, 13) for grasping a respective section of rail and two electrodes (16) suitable for contact with respective sections of rail in order to carry out a flash butt weld. The head also comprises traction actuator mechanisms (20) which extend in a longitudinal direction and are connected to the two half-heads (10) to shift the two half-heads in a longitudinal direction one towards the other, the traction actuator mechanism (20) having a stroke suitable for allowing, during a cycle of welding two sections of rail, simultaneous regulation of rail tensions.

Proposed are the welding conditions under which welds are always stably formed such that the difference in hardness between flash-butt welds and rail base metal and the deflection in a bending test are in better ranges. A plurality of pieces of rail base metal are joined via welds formed by flash-butt welding, where the rail base metal has a chemical composition containing C: 0.60 to 1.20 mass %, Si: 0.10 to 1.50 mass %, Mn: 0.10 to 1.50 mass %, and Cr: 0.10 to 1.50 mass %, with the balance being Fe and inevitable impurities, and the flash-butt welding is performed with an amount of welding heat input of 1.5010.sup.5 kA.sup.2sec or more and 4.5010.sup.5 kA.sup.2sec or less.

Proposed are the welding conditions under which welds are always stably formed such that the difference in hardness between flash-butt welds and rail base metal and the deflection in a bending test are in better ranges. A plurality of pieces of rail base metal are joined via welds formed by flash-butt welding, where the rail base metal has a chemical composition containing C: 0.60 to 1.20 mass %, Si: 0.10 to 1.50 mass %, Mn: 0.10 to 1.50 mass %, and Cr: 0.10 to 1.50 mass %, with the balance being Fe and inevitable impurities, and the flash-butt welding is performed with an amount of welding heat input of 1.5010.sup.5 kA.sup.2sec or more and 4.5010.sup.5 kA.sup.2sec or less.

The present disclosure is directed to a multi-segment device, such as an intravascular guide wire. The multi-segment device includes an elongate first portion comprising a first metallic material, an elongate second portion comprising a different metallic material, the first and second elongate portions being directly joined together end to end by a solid-state weld, and a heat affected zone surrounding an interface of the weld where the first and second portions are joined together, wherein the heat affected zone has an average thickness of less than about 0.20 mm.