A method for manufacturing a clad steel pipe is provided, wherein the clad steel pipe is manufactured by using a clad steel plate as a raw material. The clad steel plate comprises a base layer (1) and a clad layer (2) roll-bonded with the base layer (1). The method for manufacturing a clad steel pipe comprises the steps of forming, welding, and deburring; both sides of the clad steel plate are bent towards the base layer (1) side of the clad steel plate, then the forming step is carried out, and after the forming step, the opening faces of the resultant pipe blank are all in a form of the clad layer (2). According to the method for manufacturing a clad steel pipe, a clad steel pipe is manufactured by using a clad steel plate as a raw material. Thus, continuance and high efficiency of a high-frequency longitudinal welding pipe unit is fully utilized, subsequent non-continuous processes are not necessary, and the corrosion resistance at the weld of the clad steel pipe is ensured.

Aspects of the present disclosure relate to methods of coating a coiled tubing string, methods of conducting tubing operations using a coated tubing string, and associated apparatus thereof. In one implementation, a method of conducting a coiled tubing operation, includes forming a tubing string. The tubing string has a central annulus, an inner surface, and an outer surface, and the tubing string is formed from a metallic material. The method also includes coiling the tubing string onto a spool, and moving a coating into the central annulus. The method also includes curing the coating onto the inner surface of the tubing string to form a layer of the coating on the inner surface of the tubing string.

A finned tube having a tube main body, on the outside of which, in particular separate or integral, fins are arranged, preferably circumferentially, wherein the fins and/or the tube main body are of a multi-layer material.

The disclosure relates to a method for producing multi-walled tubes, in which a metal strip is rolled up to form the multi-walled tube. The metal strip has at least one steel layer, and at least one solder layer is applied to the steel layer. The solder layer consists at least in part of metal. According to the disclosure, the solder layer is applied to the steel layer by plasma coating.

The disclosure relates to a method for producing multi-walled tubes, in which a metal strip is rolled up to form the multi-walled tube. The metal strip has at least one steel layer, and at least one solder layer is applied to the steel layer. The solder layer consists at least in part of metal. According to the disclosure, the solder layer is applied to the steel layer by plasma coating.

Disclosed is a coated pipe having an amorphous inner surface and a method of manufacturing the same, whereby an amorphous alloy powder is coated on an inner surface of the pipe, thus ensuring that an amorphous structure is maintained after coating and thus coating density, corrosion resistance, and wear resistance of the pipe are improved. The coated pipe having an amorphous inner surface includes: a pipe; and a coating layer provided on an inner surface of the pipe, wherein the coating layer is an alloy or metal layer of a material different from a material of the pipe and contains an amorphous phase in a proportion of equal to or greater than 90%.

Disclosed is a coated pipe having an amorphous inner surface and a method of manufacturing the same, whereby an amorphous alloy powder is coated on an inner surface of the pipe, thus ensuring that an amorphous structure is maintained after coating and thus coating density, corrosion resistance, and wear resistance of the pipe are improved. The coated pipe having an amorphous inner surface includes: a pipe; and a coating layer provided on an inner surface of the pipe, wherein the coating layer is an alloy or metal layer of a material different from a material of the pipe and contains an amorphous phase in a proportion of equal to or greater than 90%.

A gas tube for an EGR cooler has such a structure that a metal plate having a flat plate shape is bent in a tube shape. The metal plate includes a core material, a sheath material clad on one surface of the core material or on both surfaces thereof, and an intermediate material clad between the core material and the sheath material so as to prevent magnesium from diffusing from the core material to the sheath material. The core material includes copper (Cu), silicon (Si), iron (Fe), magnesium (Mg), manganese (Mn), titanium (Ti), and aluminum (Al).

A multiple-winding pipe forming device for forming a wound pipe, the multiple-winding pipe forming device comprising: a plurality of pairs of forming rollers curling a metal sheet and winding the metal sheet into a roll shape; and a mandrel fabricated of metal, the mandrel including: a shaft disposed inside the metal sheet wound in the roll shape, one end side of the shaft being retained, which one end side is disposed upstream in a feeding direction of the metal sheet, and a working portion including a taper portion that increases in diameter from upstream to downstream in the feeding direction, wherein the taper portion is disposed at a position at which the metal sheet wound in the roll shape is sandwiched by, of the plurality of pairs of forming rollers, a pair of the forming rollers that is disposed at a downstream side in the feeding direction.

Aspects of the present disclosure relate to methods of coating a coiled tubing string, methods of conducting tubing operations using a coated tubing string, and associated apparatus thereof. In one implementation, a method of conducting a coiled tubing operation, includes forming a tubing string. The tubing string has a central annulus, an inner surface, and an outer surface, and the tubing string is formed from a metallic material. The method also includes coiling the tubing string onto a spool, and moving a coating into the central annulus. The method also includes curing the coating onto the inner surface of the tubing string to form a layer of the coating on the inner surface of the tubing string.