JP5284455B2 - Manufacturing method of oblique bottomed cylindrical member - Google Patents

Description

  The present invention relates to a method for manufacturing an inclined bottomed tubular member having an inclined bottom portion.

  When forging an inclined bottomed cylindrical member having a bottom portion inclined with respect to the axis of the cylindrical portion, for example, an engine piston, the continuous cast material is perpendicular to the axis as shown in FIGS. A cylindrical material (40) sliced into pieces is loaded into a die (41) and forged with a punch (42) to form a desired shape. In the forging process, an inclined bottom portion (44) is formed between the tip surface of the convex portion (43) for forming the cylindrical portion of the die (41) and the tip surface of the punch (42), and the material (40) is formed into the die. Filled between the inner peripheral surface of (41) and the outer peripheral surface of the convex portion (43), a cylindrical portion (45) is formed to form an oblique bottomed cylindrical member (46). In such an inclined bottomed cylindrical member (46), there is a difference in volume between the long (high) side and the short (low) side of the cylindrical portion (45), and the long side is reliably filled with material. The long side is molded by lowering the slide and applying a load. However, when molding is performed with a high load, burrs are formed on the short side that has been molded first, and the mold life is shortened by molding with a high load. Further, a entanglement defect tends to occur at a position where the metal flow from the short side and the metal flow from the long side collide with each other.

  On the other hand, in order to manufacture a forged product having a complicated shape having warpage and waviness, it has been proposed to use a slice material cut at an angle inclined with respect to the casting direction of the continuous cast material as a forging material (Patent Document 1). ). Even in the forging of slanted bottomed tubular members, when producing a forging material, the use of a material that approximates the volume balance of the forged product by obliquely cutting one end face suppresses the occurrence of entrainment defects. The load is likely to be reduced.

Japanese Patent Laid-Open No. 2004-230437

  However, manufacturing a forging material by machining is time consuming, and the processing cost is wasted, resulting in poor material yield and increased manufacturing costs. Moreover, if the cutting is performed obliquely, the labor and the machining allowance are increased as compared to cutting at a right angle.

  In view of the above-described technical background, an object of the present invention is to provide a method for manufacturing an oblique bottomed cylindrical member capable of producing an obliquely bottomed tubular member having good dimensional accuracy at a low cost.

  That is, the oblique bottomed cylindrical member of the present invention has the configuration described in [1] to [8] below.

[1] In a method of manufacturing an oblique bottomed tubular member having a bottom portion that is inclined with respect to the axis of the tubular portion at one end of the tubular portion,
A preforming step of forming a preform by upsetting, and a main forming step of forging the preform and forming an oblique bottomed tubular member;
The oblique bottomed tubular member is virtually divided by a plane parallel to the forging direction through the axis in the middle of the inclination direction of the bottom portion, with the high side of the cylindrical portion being the high half and the low side being low. Half and
A preform corresponding to the first half and the second half corresponding to the high half of the oblique bottomed cylindrical member on a plane passing through the axis and parallel to the upsetting direction is formed in the preform formed in the preforming step. Virtually divided into half parts, where the ratio of the volume of the high half part to the whole volume of the oblique bottomed tubular member is 1, the ratio of the volume of the first half part to the whole volume of the preform is 0.9. A method for producing an oblique bottomed cylindrical member, characterized by being in the range of -1.2.

  [2] In the preceding item 1, the difference in volume between the first half and the second half of the preform is larger than the difference in volume between the high half and the low half of the oblique bottomed tubular member. The manufacturing method of the slanted bottomed cylindrical member.

  [3] The method for manufacturing an oblique bottomed cylindrical member according to the above item 1 or 2, wherein the oblique bottomed cylindrical member has a volume of a high half portion larger than a volume of a low half portion.

  [4] The oblique bottomed cylindrical member according to any one of [1] to [3], wherein in the preforming step, a preform having a diameter expanded from a small-diameter material to the same diameter as the oblique bottomed tubular member is formed. Production method.

  [5] In the pre-forming step, a pre-formed product having an end face inclined with respect to the axis is formed, and the high side of the peripheral wall is the first half and the low side is the second half. The manufacturing method of the diagonal bottomed cylindrical member in any one of -4.

  [6] The method for manufacturing an oblique bottomed cylindrical member according to any one of the above items 1 to 5, wherein the preform has a positioning portion that determines a loading position on a forging die.

  [7] The manufacturing method of the oblique bottomed cylindrical member according to the above item 6, wherein the positioning portion is a convex portion that protrudes from the peripheral wall of the preform and is fitted into a groove provided in the forging die.

  [8] The method for manufacturing an oblique bottomed cylindrical member according to any one of the preceding items 1 to 7, wherein a concave portion is formed on the inclined end surface of the preformed product with respect to the oblique bottomed cylindrical member having a concave portion at the bottom.

  According to the manufacturing method of the slanted bottomed tubular member described in [1] above, the volume ratio of the slanted bottomed tubular member is reflected in the volume ratio of the preformed product. A slanted bottomed cylindrical member that is good and has good dimensional accuracy can be manufactured, and the mold life is extended. Further, since the preform is manufactured by upsetting, a preform with high dimensional accuracy can be formed in a short time, and no material is wasted.

  According to the manufacturing method of each inclined bottomed cylindrical member as described in [2] and [3] above, the metal flow is particularly improved and the above effect becomes remarkable.

  According to the method for manufacturing each inclined bottomed cylindrical member described in [4] above, the preformed product has a shape closer to the inclined bottomed cylindrical member, and the above effects can be remarkably exhibited.

  According to the manufacturing method of the slanted bottomed tubular member described in [5] above, the shape of the preform can be easily determined.

  According to the manufacturing method of the oblique bottomed cylindrical member described in [6] above, it is possible to load the preformed product at a predetermined position in the forging die. Further, since the preform is fixed, the risk of die breakage can be reduced.

  According to the manufacturing method of the oblique bottomed cylindrical member described in [7] above, the forging die can be easily manufactured and the mold is not easily damaged.

  According to the manufacturing method of the slanted bottomed tubular member described in [8] above, since the preform has a shape closer to that of the slanted bottomed cylindrical member, the material is not wasted. Further, it is not necessary to form a positioning fitting portion in the main mold.

It is a perspective view which shows one Embodiment of the diagonal bottomed cylindrical member manufactured by this invention. It is a perspective view which shows the preform for manufacturing the diagonal bottomed cylindrical member of FIG. It is sectional drawing which shows the main shaping | molding process in this invention typically, (A) shows the forge preparation state which loaded the preform with the die, (B) shows the forge completion state which lowered | hung the punch to the bottom dead center. ing. It is a perspective view which shows the other example of a preforming product. It is a perspective view which shows the further another example of a preforming product. It is sectional drawing which shows the conventional forging process typically, (A) shows the forge preparation state which loaded the raw material to the die | dye, (B) has shown the forge completion state which lowered | hung the punch to the bottom dead center.

FIG. 1 shows an example of an inclined bottomed cylindrical member (1), and FIG. 2 shows a preform (10) for forming the inclined bottomed cylindrical member (1). 3 (A) and 3 (B) show a forging device for producing the oblique bottomed tubular member (1) by forging the preform (10).
[An oblique bottomed tubular member]
The oblique bottomed cylindrical member (1) has one end of a cylindrical section (2) having a circular cross section that opens at a plane orthogonal to the axis (Q _s ) of the cylindrical section (2), and the other end is an axis (Q _s ) Is a cup-shaped molded product closed by a bottom portion (3) inclined with respect to. The inclined bottom (3) has an elliptical shape, and a circular recess (4) is formed on the outer surface of the bottom (3). Further, the positioning portion (5) protrudes from the cylindrical portion (2) at one end of the elliptical bottom portion (3) in the major axis direction.

In the inclined bottomed cylindrical member (1), the inclined bottomed cylindrical member (1) is virtually divided into two regions by a vertical plane (plane parallel to the forging direction) passing through the axis (Q _s ), The high side of the cylindrical part (2) is called the high half part (SH), the low side is called the low half part (SL), the total volume is (VS), and the volume of the high half part (SH) is (VSH). ), The volume of the lower half (SL) is (VSL). Since the bottom (3) is inclined, the volume (VSH) of the high half (SH) is larger than the volume (VSL) of the low half (SL).
[Preliminary products]
The preform (10) is a substantially cylindrical body, one end face is orthogonal to the axis (Q _P ) of the cylinder, and the other end face (11) is inclined with respect to the axis (Q _P ) to have an elliptical shape. Presented, a circular depression (12) is formed. At one end in the major axis direction of the elliptical end surface (11), a positioning convex portion (13) protruding from the peripheral wall is formed. The positioning convex portion (13) is for determining the position when the preform (10) is loaded on the die (20) in the main molding step.

In the preform (10), the preform (10) is virtually divided into two regions on a vertical plane passing through the axis (Q _P ), and the higher side of the peripheral wall is the first half (P1). ), The lower side is called the second half (P2), the total volume is (VP), the volume of the first half (P1) is (VP1), and the volume of the second half (P2) is (VP2) To do. The first half (P1) and the second half (P2) correspond to the high half (SH) and the low half (SL) of the oblique bottomed tubular member (1). Since the elliptical end face (11) is inclined, the volume (VP1) of the first half (P1) is larger than the volume (VP2) of the second half (P2). Further, the total volume (VP) of the preform (10) is equal to the total volume (VS) of the oblique bottomed cylindrical member (1).
[Preliminary molding process]
The material is upset, and the diameter is enlarged to be substantially the same as that of the oblique bottomed cylindrical member (1), and one end surface is inclined to form an elliptical end surface (11) and a depression (12 ) And projecting the positioning portion (12), the preform (10) is manufactured.

The preform (10) has a volume ratio (VP1: VP2) of the first half (P1) and the second half (P2) to the high half (SH) of the oblique bottomed tubular member (1). The shape is made to match or approximate the volume ratio (VSH: VSL) of the low half (SL).
[Main molding process]
The forging device shown in FIGS. 3 (A) and 3 (B) includes a die (20) and a punch (26). The die (20) is provided with a molding convex part (22) corresponding to the hollow part of the slanted bottomed tubular member (1) at the bottom part of the molding hole (21), and the tip end face (23) thereof is slanted. Corresponding to the bottom part (3) of the bottom cylindrical member (1), it is inclined to the lower right on the drawing, and the high half part (SH) is formed on the left side and the low half part (SL) is formed on the right side. Yes. Further, a groove (24) for fitting the positioning convex portion (13) of the preform (10) is provided on the peripheral wall of the molding hole (21). (25) in the figure is a knockout pin for protruding a forged product.

  The punch (26) has a front end surface (27) that is inclined downwardly to the right in the drawing corresponding to the bottom portion (3) of the oblique bottomed tubular member (1), and is a circular shape for forming a recess (4). A convex part (28) is provided. Further, the peripheral wall of the punch (26) is provided with a convex portion (29) that fits into the groove (24) of the die (20).

  As shown in FIG. 3 (A), the preform (10) is put into the molding hole (21) of the die (20), and the positioning projection (13) is fitted into the groove (24). As a result, the rotation of the preform (10) is restricted in the molding hole (21) of the die (20) so that the first half (P1) is located on the left side of the molding hole (21) in the drawing. Loaded.

Then, as shown in FIG. 3 (B), the punch (26) is lowered and a load is applied to the preform (10) to form the tip (27) of the punch (26) and the die (20). The material between the front end surface (23) of the convex part (22) is made to flow and filled between the peripheral wall of the molding hole (21) of the die (20) and the peripheral wall of the convex part for molding (22) A bottom portion (3) having an inclined thickness is formed and a cylindrical portion (2) is formed. At the same time, the circular protrusion (28) of the punch (26) is fitted into the recess (12) of the preform (10), and the circular recess (4) of the bottom (3) is formed by the load. After the punch (26) is lowered to the bottom dead center and forging is completed, the punch (26) is raised, the knockout pin (25) is raised, and the forged oblique bottomed cylindrical member (1) is ejected. (Not shown). Since the forged oblique bottomed cylindrical member (1) is connected to the positioning convex portion (5), it is cut off.
In this forging process, the volume ratio (VP1: VP2) of the preform (10) matches or approximates the volume ratio (VSH: VSL) of the slanted bottomed tubular member (1). Metal flow is better than forging from a preform (volume ratio: VP1 = VP2). For this reason, the material can be reliably filled in the die with a lower load than in the past, and the oblique bottomed tubular member (1) with a low load and good dimensional accuracy can be forged. In addition, since the forging can be performed with a low load, the die life is improved and the entrainment defects are also suppressed.

  In the preforming step of the present invention, the preform (10) is formed by upsetting. The manufacturing method and shape of the material used for upsetting are not limited. For example, a continuous cast material or an extruded material sliced and cut, an extruded material obtained by solidifying and extruding a rapidly solidified metal powder, and the like are used. . The preform (10) preferably has the same diameter as the oblique bottomed tubular member (1), but to produce a preform by obliquely cutting the material, the preform (10) has the same diameter as the oblique bottomed tubular member. A material is required, and combined with the fact that the cut surface is inclined, the cutting area is increased, the machining cost is increased, and the material yield is deteriorated. In addition, as the diameter of the material increases, the metal structure at the center portion tends to become rough, and when a preform having a rough metal structure is forged, the rough metal structure may be carried over to the oblique bottomed cylindrical member. In upsetting, large-diameter preforms can be manufactured from small-diameter materials, so there are few problems caused by the metal structure of the materials, and no processing cost is required, so the material yield is good and the production is quicker than cutting. it can. Further, the dimensional accuracy is better than cutting, and the positioning portion can be formed simultaneously. Furthermore, since burrs do not occur in upsetting, the material yield is good and no deburring work is required. The cost can be reduced by improving the material yield, shortening the preforming time, and extending the die life described above.

  The volume ratio (VP1: VP2) of the preform (10) matches or approximates the volume ratio (VSH: VSL) of the oblique bottomed tubular member (1), thereby improving the metal flow in the main forming step. The above-described effects can be obtained. The approximate range in which such an effect can be obtained is that when the ratio (VSH / VS) of the volume (VSH) of the high half portion (SH) to the total volume (VS) of the oblique bottomed cylindrical member (1) is 1, The ratio (VP1 / VP) of the volume (VP1) of the first half (P1) to the total volume (VP) of the molded article (10) is preferably in the range of 0.9 to 1.2, and more preferably 1 to A range of 1.05 is preferred.

  Further, even in the preferred range described above, the difference in volume (VP1-VP2) between the first half (P1) and the second half (P2) of the preform (10) is expressed by the oblique bottomed cylindrical member. The metal flow is further improved by setting larger than the volume difference (VSH−VSL) between the high half (SH) and the low half (SL) of (1). The reason is that the metal flows to the short side after forming the long side of the cylindrical part, and the flow is easier, and the reverse flow, that is, the metal is not easily moved from the short side to the long side. .

Further, the inclination angle (θ _P ) of the end surface (11) of the preform (10) is matched with or approximated to the inclination angle (θ _S ) of the bottom portion (3) of the inclined bottomed tubular member (1). By doing so, the volume ratio is also approximated. Therefore, even if the volume ratio of the oblique bottomed cylindrical member (1) is not strictly calculated, the shape of the preform (10) can be determined by the inclination angle (θ _S ) of the bottom (3). An effect is obtained. In particular, in an inclined bottomed cylindrical member (1) in which the opening surface of the cylindrical portion (2) is orthogonal to the axis (Q _S ) as in the illustrated example, the inclination angle (θ _P ) (θ _S ) is approximated. Since the volume ratios agree well just by making them, it can be recommended as a simple method for determining the shape of the preform. However, in a complicated shape product having a change in thickness at the cylindrical portion or the bottom portion, the inclination angle (θ _P ) of the end face of the preformed product is matched with the inclination angle (θ _S ) of the bottom portion of the oblique bottomed cylindrical member. There are cases where the volume ratios do not coincide with each other.

  The method of the present invention can be applied as long as the oblique bottomed tubular member has a bottom portion that is inclined with respect to the axis, and the shape and thickness of the tubular portion, the presence or absence of irregularities formed on the bottom portion, etc. are limited in any way. Not. For this reason, the height of the peripheral wall of the cylindrical part may be lower on the higher side than the lower side (lowering side) of the inclined bottom, and the volume of the lower half is higher than that of the higher half. Sometimes it grows. It is possible to improve the metal flow by reflecting the volume ratio of the two halves virtually divided into the volume ratio of the preform for the oblique bottomed cylindrical member of any shape, and exhibit the above-described effects. it can. However, a particularly remarkable effect is obtained in a shape in which the volume (VSH) of the high half (SH) is larger than the volume (VSL) of the low half (SL) as in the above-described oblique bottomed cylindrical member (1). can get. That is, a high effect can be obtained when the mold life is deteriorated by forming the short side first.

  The virtual division is most preferably performed on a surface that passes through the axis and maximizes the volume difference. In this way, when the virtual division is performed, the metal flow in the main forming process becomes the best. However, the present invention is not limited to performing the virtual division that maximizes the volume difference, and may be performed at an arbitrary position in the middle of the tilt direction, and the virtual division is performed at a position that is somewhere from the center. The volume ratio may be reflected in the preform. Furthermore, since the volume ratio of the inclined bottomed cylindrical member may be reflected in the preform, the volume ratio can be adjusted by a method such as providing a step without providing an inclined surface on the preform. However, it is preferable that the preform has a shape closer to that of the forged product. From this viewpoint, a preform having an inclined surface can be recommended.

  The preform (10) shown in FIG. 2 has one inclined surface, but the volume ratio may be approximated by inclining a plurality of surfaces. The preform (15) shown in FIG. 4A is obtained by inclining both end faces (16) and (17) of a cylindrical body in the opposite direction. Since the metal flow can be improved by reflecting the volume ratio of the inclined bottomed cylindrical member in the preform, the number of inclined surfaces is not limited at all. When the two surfaces are inclined, even if the inclination directions of the two surfaces are the same, the volume can be differentiated by changing the inclination angle.

  It is also preferable to form the irregularities formed on the oblique bottomed cylindrical member (1) also on the preform (10). Since the preform (10) having such a shape has a shape closer to the oblique bottomed cylindrical member (1), the material is not wasted. Further, when the unevenness of the preform (10) can be used as a positioning portion in the main molding die, it is not necessary to separately form a positioning fitting portion. In the above example, in order to form the depression (4) on the bottom surface of the inclined bottomed cylindrical member (1), the depression (12) corresponding to the depression (4) on the end surface (11) of the preform (10). Is formed. Of course, the oblique bottomed cylindrical member (1) having the depression (4) of FIG. 1 can be forged even using a preform (19) having no depression on the end face (18) as shown in FIG. 4B.

  Furthermore, it is preferable to form a positioning portion for loading the preform (10) into the molding hole (21) of the die (20). In the preform (10) shown in FIG. 2, the convex portion (13) is formed on the peripheral wall, while the groove (fitting to the convex portion (13) is formed on the peripheral wall of the molding hole (21) of the die (20). Positioning is performed by forming 24) and fitting them together, but the positioning projections and grooves may be provided on either the preform or the die. However, it is easier to manufacture the die and secure the strength of the die by providing the groove than providing the convex portion on the die (20), so that the die (20) is provided with the convex portion (5) on the preform (10). ) Is preferably provided with a groove (24). In addition, a positioning part is provided only on the preform without providing a positioning part on the die (20), the gripping position of the chucking device is determined by this positioning part, and the loading position is determined by moving to the die in a determined attitude. You can also decide.

  In the main forming step, it is preferable to supply the lubricant to the dies and punches as in general forging, and also to impart lubricity to the preform. As an example, when an engine piston is molded, forging load can be reduced and a valve recess failure on the crown side can be prevented by imparting lubricity to the preform. Lubricity imparting to the preform is appropriately performed by a bond processing or the like. It is also preferable to heat the die, punch and preform. In the forging of aluminum or aluminum alloy, the heating temperature of the die is preferably 200 to 400 ° C, particularly preferably 250 to 300 ° C. Similarly, the heating temperature of the punch is preferably 50 to 250 ° C, particularly preferably 100 to 200 ° C. Similarly, the heating temperature of the preform is preferably 400 to 480 ° C, particularly 420 to 460 ° C.

  In the present invention, the material of the oblique bottomed cylindrical member is not limited. However, since the metal flow in the main forming process is improved, the elongation is poor and a remarkable effect is obtained in the forging of the hardly forged material. Examples of such materials include aluminum alloys containing Si, Cu, Ni, Mg, and Fe. For example, Si: 10.5 to 13.5 mass%, Cu: 3 to 5 mass%, Ni: 1 to 3 mass%, Fe: 0.1 to 0.5 mass%, Mg: 0.8 to 1. Aluminum alloy containing 2% by mass, or Si: 11-12% by mass, Cu: 3-5% by mass, Mg: 1-1.4% by mass and Fe: 4-6% by mass, especially An aluminum rapidly solidified powder alloy having the above composition can be listed. In the former alloy, a preferable Si concentration is 11.5 to 12.5% by mass, a preferable Cu concentration is 3.5 to 4.5% by mass, a preferable Ni concentration is 1.5 to 2.5% by mass, and a preferable Fe concentration. Is 0.3 to 0.5 mass%, and the preferred Mg concentration is 0.9 to 1.1 mass%.

An oblique bottomed tubular member (1) shown in FIG. 1 was produced using an alloy having the composition shown in Table 1. The oblique bottomed cylindrical member (1) has a cup shape in which one end of a cylindrical section (2) having a circular cross section is opened and the other end is closed by a bottom section (3) inclined with respect to the axis (Q _s ). It is a molded product. The inclination angle (θ _S ) of the bottom portion (3) is 7.5 °, and a circular recess (4) is formed on the outer surface of the bottom portion (3). The volume ratio (VSH: VSL) of the high half (SH) and the low half (SL) virtually divided by the vertical plane passing through the axis (Q _S ) is 54%: 46%.

[Examples 1 to 12]
In each example shown in Table 2, a preform having an inclined surface is manufactured by upsetting in the preforming step, and subsequently, in the main forming step, the die (20) shown in FIGS. 3A and 3B and The preformed product was forged using the punch (26) to forge the oblique bottomed cylindrical member (1).
(Preliminary molding process)
In the preforming process, Examples 1, 2, 4, 5, 7, 8, 10, and 11 were used by slicing the alloy B or the alloy C of Table 1 as the upsetting material, In Examples 3, 6, 9, and 12, solidified powder obtained by rapidly solidifying the alloy D shown in Table 1 was extruded, and this extruded material was sliced and cut. Further, the molding temperature in the upsetting process is as shown in Table 2.

In Examples 1 to 9, as shown in FIG. 4B, a preform (19) in which one end face (18) of the cylindrical body was inclined was manufactured. The inclination angle (θ _P ) of the inclined end face (18) of the preform (19) is 10 ° (Examples 1 to 3), 5 ° (Examples 4 to 6), or 15 ° (Examples 7 to 9). ), And a positioning projection (13) is provided on the peripheral wall.

In Examples 10-12, as shown in FIG. 2, a preform (10) in which one end face (11) of the cylindrical body was inclined was manufactured. The preform has a circular recess (12) on the inclined end surface (11), and a positioning projection (13) is provided on the peripheral wall. Further, the inclination angle (θ _P ) of the inclined surface (11) is 10 °.

In the preforms of Examples 1 to 12, the volume ratio (VP1) of the first half (P1) on the higher side and the second half (P2) on the lower side virtually divided by the vertical plane passing through the axis (Q _P ). : VP2) is as shown in Table 2.
(Main molding process)
In the main forming step, a lubricant was applied to the die (20) and the punch (26), and the preformed product was subjected to a bond treatment to impart lubricity. The preform was preheated to the temperature shown in Table 2, and the die (20) and the punch (26) were also heated to the temperatures shown in Table 2, respectively.

  In Examples 1 to 3 and 7 to 12, the preformed products (10) and (19) are loaded into the molding hole (21) of the die (20) with the inclined end faces (11) and (18) facing upward. 4 to 6 were loaded with the inclined end face (11) facing down. In any of the examples, the preforms (10) and (19) could be loaded at predetermined positions by fitting the positioning projections (13) into the grooves (24) of the die (20).

  The punch (26) was lowered with the following load and forged to produce an oblique bottomed tubular member (1).

XX: 0.77 MPa or more (520 t or more)
X: 0.74 MPa or more and less than 0.77 MPa (500 t or more and less than 520 t)
○: 0.72 MPa or more and less than 0.74 MPa (490 t or more and less than 500 t)
A: 0.71 MPa or more and less than 0.72 MPa (480 t or more and less than 490 t)
A: Less than 0.71 MPa (less than 480 t)

[Comparative Examples 21-33]
In each comparative example shown in Table 3, a preform for forging was produced by upsetting or machining.
(Preliminary molding process)
In Comparative Examples 21 to 27 and 31 to 33, preforms were manufactured by upsetting. As upsetting materials, Comparative Examples 21 to 23, 25, 26, 31, and 32 were obtained by slicing and cutting continuous cast materials of Alloys A, B, and C in Table 1, and Comparative Examples 24, 27, and 33 were Tables. A solidified powder obtained by rapidly solidifying the alloy D of No. 1 was extruded, and this extruded material was cut into slices. The preforms of Comparative Examples 21 to 27 were formed in a cylindrical body having both end faces orthogonal to the axis and having no inclined surfaces, as referred to the material (40) in FIG. The preforms of Comparative Examples 31 to 33 each have a shape in which both end faces of the cylindrical body are inclined at 7.5 °. Further, the molding temperature in upsetting is as shown in Table 3.

  In Comparative Examples 28 to 30, preforms were manufactured by machining. In Comparative Examples 28 and 29, the alloys B and C in Table 1 were continuously cast to the same diameter as the oblique bottomed tubular member (1), and this continuous cast material was cut so that one end face was inclined at 10 °. processed. In Comparative Example 33, a solidified powder obtained by rapidly solidifying the alloy D in Table 1 is extruded to the same diameter as the oblique bottomed tubular member (1), and this extruded material is cut so that one end face is inclined at 10 °. Was processed as follows. These cut products have the same shape as the forging material (19) of FIG. 4B except that there is no positioning portion (13).

In the preforms of Comparative Examples 21 to 33, the volume ratio (VP1) of the first half (P1) on the higher side and the second half (P2) on the lower side virtually divided by the vertical plane passing through the axis (Q _P ). : VP2) is as shown in Table 3.
(Main molding process)
Similar to the main forming step of the example, a lubricant was applied to the die (20) and the punch (26), and the preformed product was subjected to a bond treatment to impart lubricity. The preform was preheated to the temperature shown in Table 3, and the die (20) and the punch (26) were also heated to the temperatures shown in Table 3, respectively. The punch (26) was lowered and forged to produce an oblique bottomed tubular member (1). The forging load symbol is the same as in the example.

  The oblique bottomed tubular members produced in the examples and comparative examples were evaluated by the following methods and criteria for formability, form, high temperature mechanical properties, quality, and cost of the tubular portion, and further comprehensively evaluated. These evaluation results are shown in Table 2 and Table 3.

(Formability)
Evaluation was made by visual observation.
×: The cylindrical part is not formed uniformly ○: The cylindrical part is formed almost uniformly ◎: The cylindrical part is formed evenly

(Form)
Evaluation was based on the depth of entrainment defects.
×: Entrainment defect having a depth of 1 mm or more occurred ○: Depth of the entrapment defect was 0.5 mm or more and less than 1 mm ◎: Entrainment defect had a depth of 0.3 mm or more and less than 0.5 mm ◎ A: Depth of entrainment defect was less than 0.3 mm

(cost)
Relative to the cost of manufacturing 100,000 slanted bottomed tubular members, the cost is relative when the bottomed tubular member of the same shape is manufactured by casting and the cost per cast article is "1". Compared.
×: 2 or more ◎: 1.5

(High temperature mechanical properties)
High temperature fatigue strength at 300 ° C. was measured.
×: 30 MPa or more and less than 45 MPa ○: 45 MPa or more and less than 60 MPa ◎: 60 MPa or more

(quality)
×: Internal defect ○: No internal defect

(Overall)
The following criteria were evaluated by comprehensively evaluating the molding load, moldability, form defects, mechanical properties, quality, and cost.
XX: One or more XX XX: One or more X ◎: One or more ◎ ◎: Two or more ◎ ◎: One or more ◎◎ or four or more ◎

  From Tables 2 and 3, it was confirmed that an oblique bottomed cylindrical member with good dimensional accuracy can be manufactured at low cost by forging a preform that reflects the volume ratio of the oblique bottomed cylindrical member.

  According to the present invention, it is possible to manufacture an oblique bottomed tubular member with low cost and good dimensional accuracy, and for example, it can be applied to manufacture of an engine piston.

1… An oblique bottomed tubular member
2 ... Cylindrical part
3 ... Bottom
4 ... depression
5 ... Positioning convex part SH ... High half SL ... Low half
10 ... Preliminary products
11… End face
12 ... depression
13 ... Positioning convex part P1 ... 1st half part P2 ... 2nd half part
20 ... dice
26 punches

Claims (8)

In the method of manufacturing an oblique bottomed tubular member having a bottom portion inclined with respect to the axis of the tubular portion at one end of the tubular portion,
A preforming step of forming a preform by upsetting, and a main forming step of forging the preform and forming an oblique bottomed tubular member;
The oblique bottomed tubular member is virtually divided by a plane parallel to the forging direction through the axis in the middle of the inclination direction of the bottom portion, with the high side of the cylindrical portion being the high half and the low side being low. Half and
A preform corresponding to the first half and the second half corresponding to the high half of the oblique bottomed cylindrical member on a plane passing through the axis and parallel to the upsetting direction is formed in the preform formed in the preforming step. Virtually divided into half parts, where the ratio of the volume of the high half part to the whole volume of the oblique bottomed tubular member is 1, the ratio of the volume of the first half part to the whole volume of the preform is 0.9. A method for producing an oblique bottomed cylindrical member, characterized by being in the range of -1.2.   The oblique difference according to claim 1, wherein a difference in volume between the first half and the second half of the preform is larger than a difference in volume between the high half and the low half of the oblique bottomed tubular member. Manufacturing method of bottomed cylindrical member.   The said bottomed cylindrical member is a manufacturing method of the bottomed cylindrical member of Claim 1 or 2 with which the volume of a high half part is larger than the volume of a low half part.   The manufacturing method of the diagonal bottomed cylindrical member in any one of Claims 1-3 which shape | molds the preform which expanded the diameter to the same diameter as the diagonal bottomed cylindrical member from the raw material of a small diameter in the said preforming process. .   5. The preforming step includes molding a preform having an end face inclined with respect to the axis, and setting the high side of the peripheral wall as the first half and the low side as the second half. The manufacturing method of the diagonal bottomed cylindrical member in any one of.   The said preforming product is a manufacturing method of the slant bottomed cylindrical member in any one of Claims 1-5 which has a positioning part which determines the loading position to the die for forging.   The manufacturing method of the slanted bottomed cylindrical member according to claim 6, wherein the positioning portion is a convex portion that protrudes from a peripheral wall of the preform and is fitted into a groove provided in a forging die. The manufacturing method of the diagonal bottomed cylindrical member in any one of Claims 1-7 which forms a recessed part in the inclined end surface of a preforming part with respect to the diagonal bottomed cylindrical member which has a recessed part in a bottom part.

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