JPS599856B2 - Hihakaishi Kensouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to non-destructive testing equipment, particularly for testing hot objects such as hot steel pipes.

In the continuous welding method of steel pipe manufacturing, the strip is heated in a furnace to a temperature of approximately 1300°C.

After the strip exits the furnace, it is passed through a forming mill that bends the strip into a tubular shape. At or adjacent to the point where the edges of the strip are butted together to form the tube, a jet of oxygen raises the edges of the strip to the welding temperature, thereby producing a continuously welded tube. . It is often desirable to test weld lines for defects.

The object of the invention is to provide a non-destructive testing device for this purpose, which allows the tube to be tested immediately after welding while it is still hot. The invention includes a test assembly consisting of a test coil device and a container for the test coil device, the container being filled with a liquid and having a wall for liquid cooling. The container is characterized in that it has a metal face plate facing the article to be tested.

A non-destructive testing device is provided for testing hot articles. The face plate should be heat resistant, special heat resistant alloys with high electrical resistance, iron-containing metals such as alloys of nickel chromium and iron, especially Inconel, and thickness O, 508 mm ( 0,02 inches) is good.

The liquid filling the container may be any suitable electrically insulating, non-corrosive liquid, preferably an oil, such as transformer oil.

If the article to be tested is a hot steel pipe, the face plate may have a concave configuration to match the shape of the steel pipe.

The test assembly included an eddy current coil device consisting of a primary coil with two secondary coils on each side, such that during use, changes in magnetic flux linkage between the primary and secondary coils were adjacent to the coils. Indicate defects in the tube wall.

The device of the invention is particularly suitable for testing the weld line of continuously welded steel pipes, in this case immediately at the exit of the welding mill, i.e. where the steel pipe is at a temperature of approximately 1250°C and the faceplate is installed close to the weld line of the pipe.

The test assembly may be supported by a bogey pivotally supported by a fixed support, the bogey having a groove adapted to rest on the tube to be tested. Equipped with wheels.

The assembly is supported on the bogie via a frame pivotally attached to the bogie, said frame holding the face plate at a predetermined optimum distance from the hot steel pipe to be tested. It has at least one guide wheel that rolls over the top surface of the tube to be coated. Conveniently, this distance should be as small as possible to encourage maximum operating sensitivity of the coil arrangement, but should be sufficient to ensure a safe clearance between the face plate and the tube. This distance is conveniently
1.524 (0.06 inch) to 2.54 inch (0.1
(inch). In order to make the invention easier to understand, one embodiment of the invention will be described by way of example with reference to the accompanying drawings.

As can be seen, the apparatus consists of a test assembly 1 mounted in a BOgey 2, the majority of which is shown in dotted lines in FIG.

The bogie 2 essentially consists of a frame and two grooved wheels 3 adapted to run over the hot steel pipe 4 to be tested. The bogie is supported on a support 5 which is pivotally connected to the outlet end of the welding station 5 of the continuous tube welding mill. A secondary frame structure 8 is pivotally supported on the link arms 6, 7 by bogies, which secondary frame structure 8 runs along the upper surface of the tube 4 to be tested and supports the test assembly 1. Be sure to maintain some distance from the pipe.
It has five wheels 9.

As best seen in FIGS. 2 and 3, the test assembly 1 has a container 10 with an outwardly extending peripheral flange 11 abutting an inner shoulder 12 of the secondary frame structure 8. has.

The assembly 41 is held within the secondary frame structure 8 by an annular threaded member 13 surrounding the assembly 1 and screwed into the secondary frame structure 8. The container 10 has a thickness of 0.
It includes a base member or face plate 14 made of 0.02 inch Inconel 600 and shaped to match the shape of the tube to be tested.

Inside the container 10 are two secondary coils 16 on both sides,
An eddy current coil arrangement is provided having a primary coil 15 with 17. The interior 18 of the container 10 is filled with transformer oil and the assembly is such that water flows from the inlet 19 through the hole 20 in the container 10 into the annular passage 21 provided in the wall of the container and into the base member 14. The water is cooled by flowing out of the orifice 22 provided.

Electrical connections to coils 15, 16, 17 are provided for coil 1
by means of a PTFE-coated cable 23 protruding into a sealing block 24 supporting 5, 16, 17;
Said sealing block serves as the top cover of the container 10 and is attached to the container by screws 25.

For operation, a bogie 2 is mounted at the outlet end of a continuous welding station of steel pipe. Steel tubes welded at approximately 1250° C. typically pass through the equipment at a production rate of 150 meters per minute. The arrangement of the tubes is such that the weld line is directly below the equipment. The wheels 9 engage the top surface of the tube 4 and lift the curved base member 14 of the test assembly approximately 1.524 mm from the tube 4.
Maintain a distance of 0.06 inches. The primary coil 15 is energized at a frequency of 10 KHz and changes in magnetic flux linkage to the secondary coils 16, 17 are detected to provide information regarding weld defects and cross welds (CrOssweld).

The use of transformer oil filled container 10 is important.

Thus, firstly, this transformer oil acts as an electrical insulator for the coil arrangement. Secondly, this oil allows very rapid transfer of heat from the base member, and for this reason,
Despite the use of a thin base member, the assembly can be operated on hot steel pipe without damage. at the same time,
Due to the small gap between the eddy current coil and the hot steel tube being tested due to the use of a thin base member, high operating sensitivity can be achieved. Again, the use of Inconel 600 as the base member is important. This is because its high electrical resistance (103 microohms ClfL at 20° C.) means that the base member has a shielding effect that is not a problem during operation of the coil device.

[Brief explanation of drawings]

1 is a side view of an apparatus for testing hot steel pipes according to the present invention; FIG. 2 is a cross-sectional view of a portion of the apparatus shown in FIG. 1 taken along line H-H; and FIG. 3 is the apparatus shown in FIG. 1. FIG. 4... Hot article (steel pipe), 10... Container, 14... Face plate, 15... Primary coil, 16, 17... secondary coil.

Claims (1)

[Claims] 1. A non-destructive testing device for testing hot metal articles having a test assembly including an eddy current coil test device, comprising a container for the eddy current coil test device, the container being filled with an electrically insulating liquid. , the walls of the container are provided with passages for passage of a flowing cooling liquid, the container has on one side a thin face plate adapted to conform to the wall of the article under test;
The face plate is made of a heat-resistant metal with high electrical resistance, the coil device is placed close to the face plate while keeping a distance therebetween, and the electrically insulating liquid is arranged between the coil device and the face plate. A non-destructive testing device fills the space between.