JP3555353B2 - Straightening method for metal tubular parts - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for correcting a metal tubular part, and more particularly to a technique for correcting deformation of a nickel-based alloy part used for an aircraft or the like.
[0002]
[Prior art]
Nickel-based alloys and titanium-based alloys may be used for the casing of a jet engine, but the casing of the jet engine may be deformed due to heat history, vibration, metal fatigue, stress, etc. during use. is there.
[0003]
Conventionally, when deformation of a nickel-based alloy component or the like occurs, the solution is kept in a heating furnace at a temperature of 900 ° C. to 1100 ° C. and then solution-corrected. For about 24 hours.
[0004]
[Problems to be solved by the invention]
However, in the case of a nickel-based alloy component, it is difficult to improve the dimensional accuracy, for example, when trying to correct the deformation at room temperature because of the high strength and the effect of springback.
In addition, when processing at a high temperature (solution temperature) appropriate for deformation correction, stainless steel may be used as a correction type. However, the high-temperature strength of stainless steel is lower than that of nickel-based alloys, Dimensional accuracy tends to decrease.
[0005]
The present invention has been made in view of the above circumstances, and aims to achieve the following objects.
(1) Improve dimensional accuracy when correcting the deformation of the part to be corrected.
(2) Deformation due to heat treatment performed after deformation correction is suppressed.
(3) Improve workability related to deformation correction.
{Circle around (4)} Reduce costs related to deformation correction.
{Circle around (5)} Inexpensive jigs, such as stainless steel correction dies, can be used.
[0006]
[Means for Solving the Problems]
In the method of straightening a metal cylindrical part, a step of performing a solution treatment of the part to be corrected, a step of cooling the part to be corrected to around room temperature, and a step of heating and thermally expanding the part to be corrected Fitting the thermally expanded component to be corrected into the correction mold, heating the correction die and the component to be corrected, correcting the deformed portion of the component to be corrected by thermal expansion due to a rise in temperature, and A technique in which a process of performing the aging treatment of the corrected part and a step of cooling the corrected part are applied.
The fitting of the heat-expanded corrected part into the correction mold is performed, for example, at room temperature.
The correction temperature of the part to be corrected needs to be set lower than the solution heat treatment temperature, and is desirably set to a temperature lower than the aging treatment temperature.
The component to be corrected is a casing made of a nickel-based alloy and having a cylindrical cross section.
The correction mold is desirably made of a metal having a larger coefficient of linear expansion than the part to be corrected. When the part to be corrected is a nickel-based alloy, the correction mold is made of a stainless steel material.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a method for correcting a metal tubular part according to the present invention will be described with reference to the drawings.
[0008]
The part to be corrected (casing) 1 applied in the embodiment is, for example, a casing having a cylindrical cross section of an aircraft engine, and is made of a nickel-based alloy.
The casing 1 is provided with a flange 1a and a cylindrical wall 1b, and the cylindrical wall 1b has a deformed portion C, which has been deformed from a preferable shape indicated by a chain line in FIG. It is assumed that part 1a is also deformed.
[0009]
As shown in FIG. 2 (b), a modified mold 2 is combined with the casing 1, and the modified mold 2 is formed of, for example, a stainless steel material. It is set to correspond to the shape.
[0010]
Hereinafter, the state of implementation of the method for correcting a metal tubular part according to the present invention will be described in the order of steps with reference to FIGS. 1 to 3.
[0011]
[S1: Solution treatment of casing]
As shown by the solution temperature T _a in Figure 3, and the charging of the casing 1 inside the heating furnace, subjected to solution treatment at a temperature of 900 ° C. C. to 1100 ° C. For example 1 to 4 hours, which can be deformed In addition to the metallographic state, it is cooled to near normal temperature by natural cooling or the like. And D ₀ Average inner diameter near the flange 1a of the casing 1, for example at room temperature in this state.
[0012]
[S2: Thermal expansion of casing]
Inside the casing 1, if the outer diameter near the flange 1a at normal temperature when loading a modified type 2 is D _2, the loading is inhibited for example by deformation portion C, Heat the casing 1 to 0.99 ° C. to 300 ° C. , Thermal expansion. The average inner diameter in the vicinity of the flange 1a of the casing 1 when this is the D _1.
[0013]
[S3: Correction type fitting]
A casing 1 which is the thermal expansion, for example, the outer diameter near the flange 1a at room temperature conditions fit a modified type 2 is D _{2. However,} it is assumed to have the relationship _D 1> D _2.
[0014]
[S4: Heating of the part to be corrected and the correction mold]
The casing 1 and the correction mold 2 are heated inside the heating furnace to a correction temperature _Tc : 500 ° C to 600 ° C.
[0015]
[S5: Correction of deformed part]
When the casing 1 and the correction mold 2 are heated in a combined state, the expansion of the correction mold 2 becomes remarkable as the temperature of the correction mold 2 rises, and the correction mold 2 presses the outer casing 1 from the inside. .
As a result, thermal expansion accompanying plastic deformation occurs in a part of the casing 1 (for example, the deformed portion C), and plastic deformation concentrates in the vicinity of the deformed portion C. And the flange 1a is also corrected based on the correction of the deformed portion C of the casing 1.
Internal diameter _{D 3} next to the near flange 1a of this _{time, D 3> D 1> D} 2 relationship is established.
[0016]
[S6: Aging treatment]
Next, heat treatment (aging treatment) indicated by the aging temperature _Td in FIG. 3 is performed to return the casing 1 to a desired metal structure. In the aging treatment in this case, heating is performed in a heating furnace at a temperature of 600 to 800 ° C. for about 24 hours.
[0017]
[S7: Cooling]
The deformation-corrected casing 1 is cooled to a room temperature state, whereby the deformation correction step is completed. As a result, the casing 1 is the inner diameter D ₄ is the size of the normal.
[0018]
In the step S3, the correction mold 2 is set in a room temperature state. However, it is also effective to make the temperature lower than the room temperature state, and a temperature setting at which a sufficient thermal expansion can be obtained when heated to near the aging temperature. It is possible to do.
[0019]
【The invention's effect】
According to the method for correcting a metal tubular part of the present invention, the following effects can be obtained.
(1) By performing the deformation correction near the aging temperature, it is possible to improve the dimensional accuracy when correcting the deformation of the part to be corrected.
(2) By performing the deformation correction hot, it is possible to reduce the generation of stress and suppress the deformation after the deformation correction.
(3) By inserting a correction mold in a low temperature state into a heated correction part, deformation correction is performed only by thermal expansion, so that the number of steps can be reduced and workability can be improved.
(4) The cost for correcting the deformation can be reduced.
(5) By setting the temperature of the deformation correction near the aging treatment, it is possible to apply a metal material which is inexpensive and has good workability and expand the range of application.
[Brief description of the drawings]
FIG. 1 is a flowchart of an operation procedure showing an embodiment of a method for correcting a metal tubular part according to the present invention.
FIG. 2 is a front sectional view showing an embodiment of a method for correcting a metal tubular part according to the present invention, showing a combined state of a part to be corrected and a correction mold.
FIG. 3 is a temperature-time curve diagram in one embodiment of the method for correcting a metal tubular part according to the present invention.
[Explanation of symbols]
1 ... casing 1a ... flange 1b ... cylindrical wall 2 ... a modified C ... deformed portion T a _... solution temperature T c _... straightening temperature T d _... aging temperature

Claims (7)

A step of fitting the correction mold (2) into the part (1) to be corrected, a step of heating and thermally expanding the correction mold to correct a deformed portion of the part to be corrected, and a step of cooling the correction mold and the part to be corrected to cool the part. and a step of taking corrective parts, metallic tubular part methods straightening and sets the target correction part correcting the temperature (T _c) lower than the solution temperature (T _a). A step of heating the part to be corrected (1) to be in a thermal expansion state; a step of fitting a correction mold (2) into the part to be corrected which has undergone thermal expansion; and a step of heating the correction mold to thermally expand the part to be corrected. A method for correcting a metal cylindrical part, comprising: a step of correcting a deformed portion; and a step of cooling a correction mold and a part to be corrected and removing the part to be corrected. 3. The method for correcting a metal tubular part according to claim 1, wherein the correction temperature ( _Tc ) of the part to be corrected (1) is approximated to the aging temperature ( _Td ) of the part to be corrected. . 4. The metal according to claim 3, wherein after the solution to be corrected (1) is subjected to a solution treatment, the deformed portion (C) is cooled by cooling to around room temperature and then heated to near to an aging treatment suitable temperature. A method of straightening cylindrical parts. The metal cylindrical part according to claim 3 or 4, wherein the correction temperature ( _Tc ) of the part to be corrected (1) is set lower than the aging treatment temperature ( _Td ) of the part to be corrected. Correction method. The method for correcting a metal cylindrical part according to any one of claims 1 to 5, wherein the correction mold (2) is formed of a metal having a larger coefficient of linear expansion than the part (1) to be corrected. The method for correcting a metallic tubular part according to any one of claims 1 to 6, wherein the part to be corrected (1) is a nickel-based alloy.

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