JPS5829436B2 - Aluminum flange Aluminum flange - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is characterized in that the flow of processed fibers is in the longitudinal direction (direction of generatrix).
This invention relates to a method of manufacturing an aluminum alloy flange that takes into consideration weldability for aluminum alloy pipes.

Recently, large tanks for storing liquid natural gas have come to be made of aluminum alloy and forged in many cases from the viewpoint of mechanical properties at low temperatures, economy, and safety.

However, in conventional forged aluminum alloy flanges of this type, the forge flow lines of the flange were oriented horizontally with respect to the longitudinal direction of the aluminum alloy pipe to be welded, so that after the welding process with the pipe, , micro-cracking occurred near the weld, significantly reducing the strength.

Therefore, when welding a forged aluminum alloy flange to an aluminum alloy pipe in which processed fibers flow in the longitudinal direction, the present inventors discovered that the end face of the hub of the flange, that is, the welding As a result of researching the relationship between the direction and the strength after welding by changing the direction of the grain flow line on the end face to be welded, we found that the grain flow line on the end face to be welded, that is, the grain flow line at the weld groove. If the direction of the fibers in the pipe to be welded is significantly different from the direction in which the fibers flow, the above-mentioned micro-cracks will occur on the end face of the hub and its vicinity when the part solidifies due to natural cooling immediately after welding, and the strength will deteriorate. It was found that it decreased significantly.

In other words, in a forged aluminum alloy flange, all of the above defects can be eliminated by aligning the direction of the grain flow lines in the welding groove of the hub with the flow direction of the fibers in the pipe to be welded. We have reached that point.

The present invention was made based on the above-mentioned research, and it is possible to easily produce an aluminum alloy forged flange in which the direction of the grain flow lines on the end face of the hub matches the flow direction of the fibers in processing the aluminum alloy pipe to be welded. The purpose of this invention is to provide a method for manufacturing.

For this reason, the configuration of the present invention is such that at least the grain flow lines at the end face of the hub and the area near it are oriented in the longitudinal direction, and the outer diameter of the area where the end face is to be becomes a predetermined dimension. , the forging step of drawing and forging an aluminum alloy billet to obtain an intermediate silver wire, and the step of forging the bottom of an upsetting die having a bottom inner diameter equal to the outer diameter so that the portion that should become the end surface remains immobile. The intermediate silver wire is set by hitting the part, and the intermediate silver wire is strongly pressed from the side that should become the flange part to obtain the flange material. It is characterized by consisting of a machining process that involves cutting.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a central vertical sectional view showing an example of a flange obtained by the manufacturing method of the present invention, and FIG. 2 is an explanatory diagram of grain flow lines in the cross section.

In FIGS. 1 and 2, a is a round flange made of aluminum alloy, which is mainly made by forging as described later.

1 is a hub, 2 is a flange, 3 is a central through hole, 4 is an end face of the hub 1, 5 is a part of a corner, and 6 is a grain flow line.

This flange a is used by being welded to an aluminum alloy pipe e, as shown in Fig. It is oriented towards said pipe e so as to correspond to the direction of the process fiber flow 7.

That is, as shown in FIG. 6, the end surface 4 of the hub 1 is cut to form a welding groove 12, and the end surface of the pipe e is similarly formed with a groove 13, so that both a and The groove 12 of the hub 1 in the vicinity of the welded part 14 and the grain flow line 6 in the vicinity are oriented toward the fiber flow 7 of the processing of the pipe e, so the hub 1 is welded. No micro cracks occur due to welding.

Next, one embodiment of the present invention will be described.

First, as shown in Fig. 3, a round aluminum alloy billet b with an outer diameter B and a height h is placed so that the grain flow lines 6' are in the longitudinal direction and the outer diameter is D'. The intermediate silver wire C having a round shape is obtained by drawing and forging.

Here, there is a relationship h<H, B>D'>D, and
D' is larger than the outer diameter of the end surface 4 of the hub 1 of the product flange a by the machining allowance (approximately 5 to 10 threads), and the weight of the billet b is the weight of the product flange a plus the machining allowance. The weight is the sum of the amount and the surcharge.

Next, as shown in FIG. 4, an installation is made in which the inner diameter of the bottom part 9 is equal to the above-mentioned outer diameter D', and the part corresponding to the corner part 5 of the flange a is a curved surface with an appropriate radius R. The filling mold 8 is fixed on the bottom plate 10, and the intermediate silver wire C is set therein.

That is, the lower end surface 4' of the silver wire C is connected to the bottom 9 of the mold 8.
, and only its lower end surface 4' remains stationary.

Then, the press 11 applies strong pressure to the silver wire C from above.

Then, as shown in FIG. 5, a flange material d having a grain flow line of 6" is obtained.

Here, even with the strong pressure, the lower end surface 4' of the silver wire C
Since the end face 4' and the vicinity thereof are not deformed, there is no change in the grain flow line at the end face 4' and the vicinity thereof, and just as the grain flow line at the lower end face 4' of the intermediate silver wire C is maintained as it is.

Next, the flange material d is removed from the mold 8, a through hole 3 is made in the center by cutting, and the outer surface etc. are cut to a specified size to obtain a product as shown in FIG.

Incidentally, it is preferable to perform groove processing to form the groove portion 12 during this machining process by cutting.

As described above, the main steps of the present invention are a forging step in which an aluminum alloy billet is drawn and forged to obtain an intermediate silver wire rod, and a flange material is obtained by pressurizing the intermediate silver wire rod using an upsetting die. Since it is an upsetting process, it is possible to orient the grain flow lines at least in the end face of the hub and its vicinity in the correct longitudinal direction, and in the upsetting process, the crystal grains can be properly oriented. to be precise,
Weld cracking can be further prevented and product quality can be maintained constant.

In particular, in the forging process, the outer diameter of the end face of the hub and the area near it in the intermediate silver wire is set to a predetermined dimension, that is, the outer diameter of the end face of the hub of the product flange is made larger by the processing allowance. In the upsetting process, the end face is placed on the bottom of a sliding mold having an inner diameter of the bottom equal to the outer diameter, and the intermediate part is placed so that the end face remains immovable. Since the forged wire material is set and the flange material is obtained by strongly pressing the intermediate forged wire material from the side that should become the collar of the flange, the strong pressure also applies to the end surface of the hub and its vicinity in the intermediate forged wire material. The part is not deformed, and the grain flow line in that part remains unchanged and remains as it is, making it possible to accurately and easily obtain a predetermined grain flow line.

In addition, since the necessary parts of the flange material are cut to the specified dimensions by machining, the parts that could not be formed in the upsetting process or the parts for which accuracy could not be expected can be cut to the specified dimensions. , products with accurate dimensions can be easily obtained.

In addition, the flange obtained by the present invention has the end face of the hub and the grain flow lines in the vicinity thereof matching the flow direction of the fibers in the processing of the aluminum alloy pipe to be welded. No microcracks occur due to thermal effects, and the mechanical strength is excellent, so there is no risk of breakage even when fluid pressure is applied or temperature changes occur.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a central vertical cross-sectional view showing an example of a flange obtained by the present invention, Fig. 2 is an explanatory view of grain flow lines in the cross section, and Fig. 3 is an example of the flange obtained by the present invention. An explanatory diagram of the training process of the example,
Figure 4 is an explanatory diagram showing the relationship between the intermediate forged wire of the mold in the upsetting process, Figure 5 is an explanatory diagram of the state after the upsetting process, and Figure 6 shows the flange shown in Figure 1. It is an explanatory view of a state in which it is welded to a pipe. a...flange, b...billet, C
...Intermediate forged wire rod, d...Flange material, e...Pipe, 1...Hub, 2...
...Brim part, 3...Through hole, 4...
End face of hub, 4'...Lower end face of intermediate forged wire material (or lower end face of flange material), 5...Part of corner, 6° (i/, 5//... ...Karyu line, 7...
...processed fibers, 8...molds, 9...
・Bottom, 10... Bottom plate, 11... Press, 12, 13... Bevel section, 14...
welded part.

Claims (1)

[Claims] 1. Draw and forge an aluminum alloy billet so that at least the grain flow lines at the end face of the hub and the area near it are oriented in the longitudinal direction, and the outer diameter of the area where the end face is to be the specified size. a forging step to obtain an intermediate forged wire rod; and a forging step to obtain an intermediate forged wire rod, and a forging step in which the portion that is to become the end surface is placed in the bottom of an upsetting die having a bottom inner diameter equal to the outer diameter so as to maintain an immovable state. An upsetting process in which a forged wire is set and the intermediate forged wire is strongly pressed from the side that will become the flange flange to obtain a flange material, and a machining process in which the required portion of this flange material is cut to specified dimensions. A manufacturing method for forged aluminum alloy flanges that takes weldability into consideration.