JPS5951372B2 - Method for manufacturing a cylindrical member having a circumferential protrusion on the inner and outer surfaces or the inner surface using a cylindrical member having a circumferential protrusion on the outer surface as a blank tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a cylindrical member having a circumferential convex portion made of a different material on a part of the outer surface in the axial direction of a straight pipe part as a blank pipe, and makes the outer surface part from the blank pipe a different material. The present invention relates to a method for obtaining a cylindrical member having a circumferential convex portion on the inner and outer surfaces or the inner surface.

For example, when a relatively soft tube is used to require high toughness and circumferential grooves are formed on a part of its outer surface, the grooves should be as shown in Figure 1 in order to improve the wear resistance of the grooved part. In some cases, a part of the outer surface of the straight pipe section S is replaced with a different material in the circumferential direction.In this case, overlay welding or fitting of a half-split collar has traditionally been mainly used as a method of providing the different material. However, overlay welding has problems such as welding defects and welding heat effects, and when fitting a collar, a collar fixing means is required.

However, in any case, the conventional method has the disadvantage that the inner wall thickness of the original straight pipe section S becomes thinner due to the dissimilar materials, and the strength of the pipe body is significantly reduced in this part. It was hot. By the way, the present inventor has recently succeeded in developing a method for manufacturing a tubular body having a circumferential protrusion on the inner and outer surfaces or the inner surface from a cylindrical member having a thick circumferential protrusion on the outer surface, and the present invention is directed to this new method. When manufacturing a tube body having a desired dissimilar material in the circumferential direction of the outer surface using this method, the thickness of the straight tube section at the circumferential convex portion is increased to improve the strength of the section of the tube body where the dissimilar material is attached. This is done by using a cylindrical member having a circumferential convex part made of a different material from the straight pipe part on the outer surface of a part of the straight pipe part in the axial direction as a blank pipe, and after plastically deforming mainly the circumferential convex part of the straight pipe part into a circular shape. The elliptical portion is compressed in the major diameter direction through a plurality of divided dies each having an arcuate pressing surface to form a circular shape.

Describing the present invention in detail below, first, as shown in FIGS. 2A and 2B, the raw pipe to be subjected to the present method is preliminarily coated with a different material K at the final circumferential protrusion formation position on the inner and outer surfaces or the inner surface of the straight pipe portion S. A material having a thick convex portion T in the circumferential direction is used.

Here, a preferred method for manufacturing the raw pipe may be a method of overlaying the dissimilar material K by overlay welding, or a method of fitting a cylindrical member of the dissimilar material K into the straight pipe portion S. Also, the circumferential convex portion T
Both end surfaces in the axial direction are relatively gently tapered outward in the axial direction. The diameter of such a raw pipe is reduced by plastic working to obtain the desired cylindrical member. In the first step, the raw pipe is plastically deformed mainly at its circumferential convex portion T into a circular portion. .

FIG. 3a illustrates this operation, for example, the circumferential convex portion T
An example is shown in which pressure is applied via the upper and lower backing plates XX that cover the entire surface of the do. As a result, the circumferential convex portion T is mainly made circular, and at the same time, the straight pipe portion S near the circumferential convex portion is also slightly made circular. In this case, in order to prevent the straight pipe part S from becoming excessively circular, the core metal P can be inserted into the straight pipe part S if necessary. In this way, the material pipe whose circumferential convex portion T is mainly rounded is shown in Figs. 3B and C.
In this state, the thickness of the circumferential convex portion T in the minor axis direction partially protrudes toward the inner surface. Here, the minor axis H of the circumferential convex portion T at the time of freewheeling is made smaller than the later-described die D' (it can be set in the die). Next, as the second step of the pipe shrinking step, the operation moves to reduce the diameter of the circumferential convex portion T, which has mainly been made into an inertia circle.

Figures 4A and 4b illustrate this operation, in each case with . Through a pair of upper and lower half-split dies or openings having semicircular pressure molding surfaces, the circumferential convex portion T and its vicinity are pressurized in the longer diameter direction to reduce their diameter. In the case of Fig. 4a, a method for manufacturing a final molded tube having convex portions on both the inner and outer surfaces is shown, and the die is used to press the press forming surface of the circumferential convex portion T and the straight tube portion s. A desired step d (d is arbitrary as long as it is smaller than the original height of the circumferential convex portion T) is formed between the molding surface and the molding surface. In the case of FIG. 4b, a method is shown for manufacturing a tube having a circumferential convex portion only on the inner surface of the final formed tube, and the circumferential convex portion T
The pressure-molded surfaces of the straight pipe portion S and the straight pipe portion S are flush with each other. During such diameter reduction of the inner part, if necessary to maintain the shape of the straight pipe part S, a core P can be inserted into the straight pipe part S. A lubrication treatment can also be performed. Thus, by the method shown in FIG. 4a or b, a cylindrical member having circumferential protrusions on the inner and outer surfaces or the inner surface can be obtained as shown in FIG. 5a or b. By the way, the reason why the circumferential convex portion T is made into a circular shape before the diameter reduction as described above is because if the circumferential convex portion T is not made circular in this way, as shown in FIG. This is because the circumferential protrusion T does not fit well in the half-split die or in the mouth. For example, when the circumferential protrusion T is put into the half-split die or the mouth without being turned into a circular shape, the circumferential protrusion Because of this protrusion, the circumferential convex portion T is damaged by the edges when the diameter is reduced, and the diameter cannot be reduced properly. In addition, as shown in Fig. 8a, when using a blank pipe in which both end faces in the axial direction of the circumferential convex portion T are perpendicular to the axial center, as shown in Fig. 8b, the purpose A large constriction occurs near the circumferential protrusion T' in the cylindrical member, and the outer circumferential surface of the constricted portion is not well filled due to the deformation of the circumferential protrusion T.
When using a blank tube in which both end faces in the axial direction are relatively gently tapered outward in the axial direction, the constriction is small, and the concave outer circumferential surface of the constricted part is shaped like a circumferential convex portion T.
It is well explained by the deformation of .

Note that the angle of inclination of the inclined surfaces of both end surfaces in the axial direction of the circumferential convex portion T is set at a gentle angle.
The more you do it, the smaller your waist will become. Furthermore, the shape and dimensions of the circumferential convex portion T'' formed after diameter reduction are not uniform over the entire circumference. be uniform over the entire circumference.

Although the case where only the peripheral convex portion T is reduced in diameter from the original pipe has been described above, the present invention is not limited to this, and when the straight pipe portion S is also reduced in diameter, the convex portion T is reduced in diameter. Rear, straight pipe section S
The diameter of the straight pipe portion S may be reduced after the circumferential convex portion T is reduced in diameter as shown in FIG. 4a or b.

At this time, if the straight pipe part S is long, it is preferable to carry out this process using a die that gradually reduces the diameter of the part as shown in FIG. As described above, in the case where the circumferential convex portion T on the outer surface is formed by plastic working into the circumferential convex portion T', T'' on the inner and outer surfaces or the inner surface as shown in FIGS. 5A and b, the dissimilar material K is Regardless of whether it is overlay welded or fitted within the wall thickness of S, it will be firmly integrated, and the wall thickness of the original straight pipe section S will remain almost the same at the circumferential convex section. , sufficient strength can be ensured in the circumferential convex portions T″, T″″.

Next, an example of manufacturing a cylindrical member will be shown. That is, using a raw pipe having a straight pipe part S made of carbon steel and a circumferential convex part T made of 13Cr steel and having the approximate dimensions as shown in FIG. 7a, A cylindrical member having approximate dimensions as shown in C was manufactured.

Incidentally, the circumferential convex portion T was hardened by quenching after diameter reduction processing.

Incidentally, in the above embodiment, the diameter reduction operation was carried out using a die divided into upper and lower parts, but the present invention is not limited to this. Any material having an arc-shaped pressure molding surface may be used.

As explained in detail above, according to the method of the present invention, a cylindrical member with circumferentially different materials attached to the outer surface is produced by using a normal scale pressurizing device (press) and a simple jig such as a die. , it can be manufactured without reducing the wall thickness of the original straight pipe part, that is, without reducing the strength of the dissimilar material attachment part, having a sufficient wall thickness and having a plastically worked structure. It is.

Therefore, the present invention can be said to be optimal as a method of manufacturing a cylindrical member in which it is necessary to attach a different material in the circumferential direction of the outer surface as described above.

[Brief explanation of the drawing]

Claims (1)

[Scope of Claims] 1. A cylindrical member having a circumferential convex part made of a material different from the straight pipe part on the outer surface of a part of the straight pipe part in the axial direction is used as a blank pipe, and the main circumferential convex part of the straight pipe part is made into a circular part. After being plastically deformed, this ovalized portion is compressed in the major diameter direction through a plurality of split dies each having an arcuate pressure molding surface that joins together to form a circle, thereby reducing the diameter. A method for manufacturing a cylindrical member having a circumferential protrusion on the inner and outer surfaces or the inner surface, using the cylindrical member having a circumferential protrusion as a blank tube. 2. The circumferential convex part of the dissimilar material is formed by overlay welding on the straight pipe part.The cylindrical member having the circumferential convex part on the outer surface as described in claim 1 is used as a blank pipe to form the inner and outer surfaces or the inner surface. A method for manufacturing a cylindrical member having a circumferential convex portion. 3. The circumferential convex portion of the dissimilar material is formed by fitting a cylindrical material into a straight pipe portion.The cylindrical member having the circumferential convex portion on the outer surface as described in claim 1 is used as a blank tube, and the inner and outer surfaces or A method of manufacturing a cylindrical member having a circumferential convex portion on the inner surface.