JPS60124435A - Forging method of metallic material - Google Patents

Abstract

PURPOSE:To obtain sufficiently an internal forging effect even in case of a small sectional reduction ratio by detaining an elongation in the longitudinal direction of a material by upper and lower anvils or a V-anvil exceeding a length of the material, and executing a rotation forging, in case of a free hot forging of a column or a columnar material. CONSTITUTION:A column material or a column-shaped material is placed with tongs on upper and lower anvils or a V-shaped anvil being longer than a material to be forged, so that it does not protrude from the anvil, and a rotation free forging is executed. An elongation in the longitudinal direction is detained, the forging effect appears sufficiently in the material to be forged, and even in case of forging of a small sectional reduction ratio, a good internal quality is obtained.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to a method for forging metal materials.

[Background of the invention]

Conventionally, the hot training method generally practiced is shown in Figure 1 (a).
, As shown in (b), the material that has been sufficiently and uniformly heated to a forging temperature is forged perpendicularly to the length direction of the material 1 using the upper and lower flat anvils 2 and 2' or the upper and lower flat anvils 2 and lower yakuken anvils 3. There is a forging method that involves rolling down.

However, with this forging method, if the cross-sectional reduction ratio from the steel ingot to the product is small, the forging ratio necessary for crimping the voids that exist inside the material, such as the hollow defects that are generated when the steel ingot solidifies, cannot be obtained. , voids may remain inside the product.

In this case, as a method of increasing the training ratio, the method shown in Fig. 2 (a
), (b), and (c), after compressing the material 1' in the length direction using the upsetting tool 4 and the upsetting table 5 to increase the diameter of the material, the material 1' is compressed by the forging and stretching method described above. The upsetting forging and stretching method of forging is generally practiced.

Although this upsetting forging and stretching method is capable of forging and crimping defects such as pit-like defects, it requires the use of many jigs and tools and rolling down in the length and radial directions, making it difficult to change setups during work. The disadvantage is that it takes time. In addition, the large change in shape is disadvantageous for maintaining the integrity of the surface and superficial tissues. Furthermore,
Particularly in high C-Cr steel, etc., the forging ratio is large, which may destroy the giant carbides that tend to precipitate in the segregated areas of the steel ingot, which may deteriorate the internal integrity of the product.

[Purpose of the invention]

An object of the present invention is to provide a hot wrought method that eliminates the drawbacks of the conventional upsetting forging method and can obtain a sufficient forging effect with a small area reduction ratio.

[Summary of the invention]

In order to eliminate the drawbacks of the conventional upsetting forging and stretching method, a forging method that does not require time for setup changes and can obtain a training effect equal to or higher than that of the upsetting forging and stretching method with a very small cross-section reduction ratio is needed. We need a law. The present invention can be applied, for example, to FIGS. 3(a) and 3(b).
), using upper and lower flat anvils 6, 6' having a length equal to or longer than the length of the cylindrical material 1", flatten the upper and lower flat anvils parallel to the length direction of the material 1" and over the entire length of the material 1". Anvil 6,6
In this training method, the material 1# is rolled down by applying the 1. The elongation of material 1" in the longitudinal direction is suppressed compared to the "forging and stretching method" of is suppressed, the area reduction ratio before and after forging is small,
In addition, by repeating the reduction, it becomes possible to forge-bond voids inside the material such as pocket-like defects. In addition, in this case, it is possible to forge with only the upper and lower flat anvils, so even if it is combined with other forging methods, such as forging and stretching, the setup change can be made by simply changing the direction of the anvil, improving work efficiency. 6 [Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described in detail.

4(a), (b), (c), and (d) show the forging process of the present invention, and the radial cross-sectional shape of the cylindrical material 1'' before forging is a circle. Material 1# is made into a square cross-sectional shape using the forging method according to the present invention, then similarly made into an octagonal cross-sectional shape, and finally returned to a circular cross-sectional shape.

Regarding the amount of reduction and the number of reductions necessary for forging and crimping voids inside the material such as hollow defects, many experiments have shown that when making the material into a square cross-sectional shape, the diameter of the material before forging should be 17% or more.
I confirmed that more than one time is sufficient. The rolling reduction amount and number of rolling reductions in the octagonal cross-sectional shape and the final circular cross-sectional shape are appropriately determined depending on the desired product shape.

The cross-sectional reduction ratio before and after forging differed slightly depending on the amount of reduction, number of reductions, material shape, etc., but was approximately 1.2 to 1.3.

Next, the effects of the present invention will be explained using an example in which the above process according to the present invention is applied.

The table shows the preparation time required for producing cylinder-column blooms of the same shape using 3% Cr-high C rust and applying the conventional upsetting forging method, forging method, and forging method according to the present invention. This is a summary of the results of ultrasonic flaw detection and the judgment results of dendrite inspection. The internal soundness of the "upsetting/forging and stretching method" was extremely good, but the setup time was the longest, and the results of the dendrite inspection showed that the soundness of the surface/surface structure was also disadvantageous. Ta. In addition, although the forging and stretching method was good in terms of the setup time and the soundness of the surface and surface structure, due to the small forging ratio, there were internal defects that appeared to be unforged pock-shaped defects near the internal center. Detected by ultrasonic flaw detection.

On the other hand, according to the present invention, internal defects become stepless even at a small forging ratio, where it is impossible to forge-bond defects such as pocket defects using the forging-stretching method, and upsetting with a large forging ratio The same training effect as the forging and stretching method has been obtained. In addition, the time required for setup was about 70% compared to the upsetting forging and stretching method, and the results of the Puntorai 1-inspection were generally good.

From the above results, the forging method according to the present invention can improve work efficiency by about 30% compared to the conventional upsetting forging and stretching method.
Since it is possible to forge and press the internal voids equivalent to the "upsetting/forge-stretching method" with a small ridge ratio, it has the effect of producing high-quality products.

〔Effect of the invention〕

According to the present invention, fewer jigs and tools are used and the work can be performed by simply changing the direction of the anvil, so compared to the upsetting forging and stretching method, the
It is possible to improve the efficiency by ~40%, and since the internal voids of the material can be forged and crimped with a small cross-section reduction ratio, it has the effect of forging high-quality products.

[Brief explanation of drawings]

Figure 1 is a side view of the forging and stretching method, Figure 2 is a side view of the upsetting forging and stretching method, and Figure 3 (a) is a side view of the forging method of the present invention using upper and lower flat anvils. b) is a front view, and FIG. 4 is a front view illustrating an embodiment of the present invention. 1...Material, 1'...Material, 1'''...Material, 2
..., flat anvil, 2'... flat anvil, 3... drug price anvil, 4... upsetting tool, 5 Fig. 1 (α) (b) Fig. 3 (12-) (&) Figure 4 (α) (b> (C) (1))

Claims (1)

[Claims] 1. In a metal material forging method, after heating a cylindrical or cylindrical shaped metal material to a temperature for normal hot forging, upper and lower flat anvils having a length equal to or longer than the length of the material; Alternatively, a method for forging metal materials characterized by repeatedly rolling down the material while restraining the entire length of the material using a V-anvil having an angle of 90° to 180°.