SU996468A1 - Method for local induction heating of products - Google Patents

Description

{5) METHOD FOR LOCAL INDUCTION HEATING OF PRODUCTS

1 The invention relates to the induction heating of products and can be used for local heating of the seams of spiral pipes of a finite length.

The known method of induction heating of products in the main and additional electromagnetic fields, created by inductors Cl

The disadvantage of this method is the impossibility of uniform heating of the seams of the spiral pipe.

at the ends of the products due to the specific geometry of the heating zone of the ends of the product and the properties of the current is high

Frequencies to flow along the shortest path along the surface of the product.

A: The purpose of the invention is to obtain uniform heating along the length of the weld in the area of the end of the product.

The goal is achieved by the fact that according to the method of induction, heating of products, including heating of the product in the main and additional

Electromagnetic fields formed by inducers, an additional electromagnetic field is formed by arranging the inductive turns of the inductor at an angle of not more than 20 to the end of the product.

FIG. 1 shows the heating of my product, top view; in fig. 2 the same, side view.

The inductor, which induces the turns 1 of which, creating the main electromagnetic field, is oriented along the spiral seam 2 of the tube 3, is placed opposite the heated zone k. The plane of its indy of the turns 1 is parallel to the surface of the heated zone and repeats its shape. The current 5 induced in the heating zone k by the main electromagnetic field created by coils 1 flows along seam 2 and is closed by two parallel reverse branches b and 7 on both sides of seam 2. On the one side of the main inductor along the seam axis

an additional inductor, inducing the coils 8 of which, creating a dot-complementary electromagnetic field, are rotated with respect to the inducing coils 1 in such a way that they form with the end 9 of the pipe 3 an angle yO-20 Current 10, induced in zone 4 of the seam 2 by an additional electromagnetic field, flows at an angle to the seam 2 and at a small angle to the end 9 of the pipe 3. The return branches 11 and 12 of the current 10 symmetrically close to the right and left of the current 10. The branches 10, 11 and 12 of the current are approximately parallel to the end 9, are evenly distributed relative to the seam 2 and produce t is equally mer heating zone 4. inducts additional inductor coils 8 are arranged in the plane of the main coils 1 and inductor constitute an angle d with them, selected in the range (a.

The angle p) is measured between the end face 9 of the product and the axis of the heated zone k, in this case the seam 2 of the pipe 3

In some cases, depending on the speed of movement of the pipe under the inductors, on the magnitude of the power transmitted to the pipe by inductors with inducting coils located along the seam and at an angle to it, pipe forming angle, current frequency, pipe material, angle C of the inducing coils B additional

inductor to turns 1 of the main inductor is increased in comparison with the angle fb to 20 °. This achieves some heat loss in the previously overheated

zone and vice versa.

The use of this method of local induction heating of products makes it possible: to avoid uneven heating of the pipe ends and to perform heat treatment of pipes of a finite length without trimming the ends. Metal saving with annual pipe output equal to 800 million tons

I,. f

is million tons.

Claims (1)

1. USSR author's certificate "396375, cl. C 21 D 1/12, 1973.