JPS58145384A - Manufacture of clad steel tube - Google Patents

Abstract

PURPOSE:To manufacture clad steel tubes continuously at low cost, by build-up welding a clad material of different kind on the surface of steel tube material and turning the surface smoothly to work it into a layer. CONSTITUTION:Welding wires 4 different in chemical composition from a base material 2 are sent to the steel tube base material 2 formed to a specified size by forming rolls of the final stage from plural sets of feeding rolls 3. The base material 2 is moved in the direction of the arrow while turning the material to build-up welding the clad material on the surface of the steel tube material 2 by the welding wires 4. The build-up welded clad material 5 is turned smoothly with a cutting tool 6 by rotation of the base material 2 and clad steel tubes on which layered clad material 5 is joined on the surface are formed continuously. By this way, the number of man-hours can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for continuously manufacturing clad steel pipes made of different materials mutually made of nickel metal at a low cost.

Steel pipes for boilers and steel pipes for the chemical industry that are used as heat transfer tubes for heat exchangers are exposed to different environments on their inner and outer surfaces, so unless high-grade materials are used, corrosion resistance will be poor. In many cases, problems occurred in terms of strength and high temperature strength.

In particular, since it has excellent corrosion resistance and high-temperature strength, which is rare, it has become common to use composite materials that are a combination of two or more materials with different properties.

For example, if the inner circumferential surface requires high-temperature strength and the outer circumferential surface requires corrosion resistance, a small diameter steel pipe with high high temperature strength and a large diameter steel pipe with excellent corrosion resistance are fitted in advance. −
These are drawn to a predetermined diameter and joined together to form a nine-clad steel pipe. In this case, in order to join two types of steel pipes with different properties, both 1) The mating surface must be cleaned in advance, and rounding requires forming a group of round pieces made of high-temperature strength material and excellent corrosion resistance into a tubular shape, which has the disadvantage of being time-consuming and costly. Nine. In addition, there was also a drawback that it was not possible to continuously manufacture long tubes because the tubes had to be fitted into each other.

An object of the present invention is to provide a novel method for manufacturing clad steel pipes that can overcome the disadvantages of high cost and inability to manufacture clad steel pipes continuously using conventional methods.

The method of manufacturing a clad steel pipe according to the present invention that achieves this objective has a structure in which a clad material having a chemical composition different from that of the steel pipe base material is overlay-welded on the surface of a steel pipe base material, and then this surface is turned to make it smooth. The invention is characterized in that the cladding material is formed in a layered manner on the surface of a steel pipe.

The details of one embodiment of the method for producing clad steel pipes according to the present invention will be described below with reference to FIG. 1, which shows the working principle.
K.Explain. A welding wire 4 is held around the round steel pipe base material 2, which has been formed to a predetermined size by the final stage forming roll IK, and is held by the feed rollers 3 and fed to the steel pipe base material 2 side. The steel pipe base material 2 is rotated and moved to the right in the figure so that the clad material 5 is sensually welded to the surface of the steel pipe base material 2 by the welding wire 4. Ru. In this case, the welding wire 4 and the cutting tool 6 (described later) may be rotated around the steel pipe base material 2 without rotating the steel pipe base material 2. In front of the welding wire 4,
Meat sensation #! ! The rounded cutting tool 6 is provided to finish the cladding material 5 smoothly. The tjL* clad steel pipe 7 is continuously formed by joining the clad material 5.

[1] If it is difficult to feed the wire 4 with the feeding roller 3, 2. As shown in Fig. 2, which shows the concept of overlay work in another embodiment of the present invention, An electrode rod 9 is inserted into a round formwork 8 corresponding to the above, an arc is generated between the electrode rod 9 and the steel pipe base material 2, and the melted electrode rod 9 is used as the cladding material 5 to form a tube base material. It is preferable to coat the surface of material 2 with ms grade meat. Thereafter, the clad material 5t is turned smoothly using a cutting tool (not shown) to form the clad steel pipe 7, which is the same as in the embodiment described above.

Incidentally, it is natural that slag lO is also generated within the formwork 8.

In the above-mentioned two embodiments, the cladding material S is formed in a layered manner only on the outer peripheral surface of the steel pipe base material 20, and the cladding material 5 is also formed in a layered manner on the inner circumference 1iK of the tube base material 2. , it is also possible to form it only on the inner circumferential surface of the kernel.

As described above, according to the method for manufacturing a clad steel pipe of the present invention,
The clad material was internally welded to the surface of the steel pipe base material, and the surface was turned smoothly using a cutting tool to obtain a clad steel pipe with a layered clad material formed on the surface. Clad steel pipes can be manufactured continuously by preparing only the steel pipe base material, and since turning is performed in parallel with sensuous welding, it is possible to reduce the number of man-hours, thus reducing costs. Can be done.

[Brief explanation of the drawing]

FIGS. 1 and 2 are conceptual diagrams of different working conditions of one embodiment of the method for manufacturing clad steel pipes using unexploded fIAK. In the figures, 2 is a steel pipe base material, and 4 is a welding wire. 5 is a clad material, 6 is a cutting tool, and 7 is a clad steel pipe. 9 is an electrode rod. Patent applicant Mitsubishi Heavy Industries, Ltd.

Claims (1)

[Claims] A clad material having a chemical composition different from that of the steel pipe base material is welded to the surface of the steel pipe base material by feel, and then this surface is turned to make it smooth to form the layered clad material on the surface of the steel pipe. A method for manufacturing clad steel pipes.