JP2017211303A - Method and apparatus for estimating heat history of precipitation-hardened aluminum alloy members - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of estimating a heat history of a precipitation-hardened aluminum alloy member, which allows for accurately estimating heat temperature the precipitation-hardened aluminum alloy member has been thermally exposed to.SOLUTION: A method of estimating a heat history of a precipitation-hardened aluminum alloy member includes: a conductivity measurement step (S10) for measuring conductivity of a precipitation-hardened aluminum alloy member before and after thermally exposure to heat; and a heat exposure temperature estimation step (S12) for estimating temperature to which the precipitation-hardened aluminum alloy member was thermally exposed by comparing change in conductivity of the precipitation-hardened aluminum alloy member before and after the heat exposure to heat and heat exposure time, and a pre-acquired change in conductivity of a precipitation-hardened aluminum alloy of the same composition as the precipitation-hardened aluminum alloy member before and after being thermally exposed to known heat and corresponding heat exposure time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thermal history estimation method and a thermal history estimation device for a precipitation-hardened aluminum alloy member exposed to heat.

  Due to the increase in operating temperature of turbochargers, compressors, etc., the usage environment of precipitation hardening type aluminum alloy members such as impellers made of precipitation hardening type aluminum alloy is approaching the limit of the capability of the material. In order to improve the reliability of the precipitation hardening type aluminum alloy member, a life design with high accuracy is required. In order to perform the life design of the precipitation hardening type aluminum alloy member with high accuracy, it is necessary to more accurately grasp the heat exposure temperature in the actual environment.

  Conventionally, the thermal exposure temperature of a precipitation hardening type aluminum alloy member has been estimated by measuring the ambient temperature around the precipitation hardening type aluminum alloy member (see, for example, Patent Document 1).

JP 2012-2231 A

  By the way, in the method of measuring the ambient temperature around the precipitation hardening aluminum alloy member as described above and estimating the heat exposure temperature, the information is not obtained directly from the precipitation hardening aluminum alloy member. There is a possibility that the heat exposure temperature of the member cannot be accurately estimated.

  Accordingly, an object of the present invention is to provide a thermal history estimation method and a thermal history estimation device for a precipitation hardening type aluminum alloy member capable of estimating the heat exposure temperature of the precipitation hardening type aluminum alloy member exposed to heat with higher accuracy. It is to be.

  The thermal history estimation method of a precipitation hardening type aluminum alloy member according to the present invention is a thermal history estimation method of a precipitation hardening type aluminum alloy member that has been exposed to heat, and the conductivity of the precipitation hardening type aluminum alloy member before and after thermal exposure. A conductivity measuring step, a change in conductivity before and after thermal exposure and a thermal exposure time in the precipitation hardening aluminum alloy member, and a known composition having the same composition as the precipitation hardening aluminum alloy member obtained in advance. Thermal exposure temperature estimation step of estimating the thermal exposure temperature of the precipitation hardened aluminum alloy member by comparing the amount of change in conductivity before and after the heat exposure and the heat exposure time in the precipitation hardened aluminum alloy subjected to the heat exposure And.

  In the thermal history estimation method for a precipitation hardening type aluminum alloy member according to the present invention, a hardness measurement step for measuring the hardness of the precipitation hardening type aluminum alloy member before and after thermal exposure, and the heat exposure in the precipitation hardening type aluminum alloy member A D value calculation step of calculating a D value based on a relational expression with a change amount of conductivity before and after and a change amount of hardness before and after thermal exposure in the precipitation hardening type aluminum alloy member, The heat exposure temperature estimation step includes a precipitation hardening type that has been subjected to a known heat exposure with the same composition as the precipitation hardening type aluminum alloy member obtained in advance and the D value and the heat exposure time of the precipitation hardening type aluminum alloy member. The D value of the aluminum alloy and the heat exposure time are compared, and the heat exposure temperature of the precipitation hardening type aluminum alloy member is estimated.

  In the thermal history estimation method for a precipitation hardening type aluminum alloy member according to the present invention, the conductivity measuring step is measured by an eddy current conductivity measuring method.

  In the thermal history estimation method for a precipitation hardening type aluminum alloy member according to the present invention, the hardness measurement step is measured by a Vickers hardness measurement method, a Rockwell hardness measurement method, a Brinell hardness measurement method, or a Knoop hardness measurement method. It is characterized by that.

  The thermal history estimation device for a precipitation hardening type aluminum alloy member according to the present invention is a thermal history estimation device for a heat treatment of a precipitation hardening type aluminum alloy member, and the conductivity of the precipitation hardening type aluminum alloy member before and after the heat exposure. A conductivity measuring means for measuring the amount of change in electrical conductivity before and after thermal exposure and thermal exposure time in the precipitation hardening aluminum alloy member, and the same composition as that of the precipitation hardening aluminum alloy member determined in advance. Thermal exposure temperature estimation means for estimating the thermal exposure temperature of the precipitation hardened aluminum alloy member by comparing the amount of change in electrical conductivity before and after heat exposure and the heat exposure time in the precipitation hardened aluminum alloy subjected to heat exposure And.

  In the thermal history estimation apparatus for precipitation hardening type aluminum alloy members according to the present invention, hardness measuring means for measuring the hardness of the precipitation hardening type aluminum alloy member before and after thermal exposure, and heat exposure in the precipitation hardening type aluminum alloy member D value calculation means for calculating a D value based on a relational expression with the amount of change in conductivity before and after and the amount of change in hardness before and after thermal exposure in the precipitation hardening aluminum alloy member, The heat exposure temperature estimation means is a precipitation hardening type that has received a known heat exposure with the same composition as the precipitation hardening type aluminum alloy member obtained in advance and the D value and the heat exposure time of the precipitation hardening type aluminum alloy member. The D value of the aluminum alloy and the heat exposure time are compared, and the heat exposure temperature of the precipitation hardening type aluminum alloy member is estimated.

  According to the above configuration, the heat exposure temperature is estimated based on the change in conductivity of the precipitation-hardened aluminum alloy member exposed to heat, so the heat exposure temperature of the precipitation-hardening aluminum alloy member is estimated more accurately. It becomes possible.

In 1st embodiment of this invention, it is a flowchart which shows the thermal-history estimation method of a precipitation hardening type aluminum alloy member. In 1st embodiment of this invention, it is a model figure which shows the relationship between the electrical conductivity in a precipitation hardening type aluminum alloy member, and heat exposure time. In 1st embodiment of this invention, it is a model figure which shows the estimation method of heat exposure temperature. In 1st embodiment of this invention, it is a block diagram which shows the structure of the thermal history estimation apparatus of a precipitation hardening type aluminum alloy member. In 2nd embodiment of this invention, it is a flowchart which shows the thermal history estimation method of a precipitation hardening type aluminum alloy member. In 2nd embodiment of this invention, it is a model figure which shows the relationship between the hardness in a precipitation hardening type aluminum alloy member, and heat exposure time. In 2nd embodiment of this invention, it is a model figure which shows the relationship between D value, heat exposure time, and heat exposure temperature. In 2nd embodiment of this invention, it is a model figure which shows the estimation method of heat exposure temperature. In 2nd embodiment of this invention, it is a block diagram which shows the structure of the thermal history estimation apparatus of a precipitation hardening type aluminum alloy member. In Example 1 of this invention, it is a graph which shows a master curve. In Example 2 of this invention, it is a graph which shows the relationship between the variation | change_quantity of the hardness before and behind heat exposure, heat exposure time, and heat exposure temperature. In Example 2 of this invention, it is a graph which shows a master curve.

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

[First embodiment]
A first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a flowchart showing a thermal history estimation method for a precipitation hardening type aluminum alloy member. The thermal history estimation method for a precipitation hardening type aluminum alloy member includes a conductivity measurement step (S10) and a thermal exposure temperature estimation step (S12).

  The precipitation hardening type aluminum alloy member is, for example, a spreading member or a casting member such as a compressor impeller used for a marine supercharger, a generator, or a vehicle supercharger. Such a precipitation hardening type aluminum alloy member is exposed to heat at about 100 ° C. to about 200 ° C. during operation of a device such as a supercharger.

  The precipitation hardening type aluminum alloy member is formed of a precipitation hardening type aluminum alloy such as JIS standard. The precipitation hardening type aluminum alloy is an aluminum alloy that is strengthened by depositing precipitates by aging treatment after solution treatment. Precipitation hardening type aluminum alloy members include, for example, Al-Cu alloys, Al-Cu-Mg alloys, Al-Mg-Si alloys, Al-Zn-Mg alloys, Al-Zn-Mg-Cu alloys, etc. (2000 series, 6000 series, 7000 series, AC1B, AC4A, AC4C, AC4CH, etc.).

  The conductivity measurement step (S10) is a step of measuring the conductivity before and after thermal exposure in the precipitation hardening type aluminum alloy member. The electrical conductivity of the precipitation hardening type aluminum alloy member is mainly influenced by the amount of solute elements in the Al matrix in the precipitation hardening type aluminum alloy. When the precipitation hardening type aluminum alloy member is exposed to heat, the solute elements dissolved in the Al matrix phase precipitate as precipitates, and the amount of solute elements in the Al matrix phase decreases, resulting in precipitation. The conductivity of the curable aluminum alloy member changes. From this, the influence of the heat exposure of the precipitation hardening type aluminum alloy member can be evaluated by the change in the conductivity before and after the heat exposure in the precipitation hardening type aluminum alloy member.

  FIG. 2 is a model diagram showing the relationship between electrical conductivity and heat exposure time in a precipitation hardening type aluminum alloy member. In FIG. 2, the horizontal axis indicates the heat exposure time, the vertical axis indicates the conductivity, and the change in conductivity is indicated by a solid line. Moreover, it is shown that the heat exposure temperature T1 is higher than the heat exposure temperature T2.

  The conductivity of the precipitation hardening type aluminum alloy member tends to increase with the passage of the heat exposure time from the start of the heat exposure. Moreover, when the heat exposure time is the same, the conductivity of the precipitation hardening type aluminum alloy member tends to increase as the heat exposure temperature increases.

  Precipitation hardening type aluminum alloy members are strengthened by precipitating precipitates composed of metastable phases by aging treatment after solution treatment. When precipitation hardened aluminum alloy members are exposed to heat, solute elements dissolved in the Al matrix phase precipitate, increasing the metastable phase and changing the metastable phase form. Is formed. When the solute element dissolved in the Al matrix phase precipitates due to heat exposure, the amount of the solute element dissolved in the Al matrix phase decreases, so the conductivity of the precipitation hardened aluminum alloy member Tend to be larger. In addition, when the heat exposure temperature increases, precipitation of solute elements dissolved in the Al matrix phase is promoted, so the decrease in the amount of solute elements dissolved in the Al matrix phase is greater. Therefore, the conductivity of the precipitation hardening type aluminum alloy member tends to be larger.

For example, when the precipitation hardening type aluminum alloy member is formed of an Al—Cu—Mg alloy, solute elements such as Cu and Mg that are solid-dissolved in the Al matrix are precipitated by heat exposure. Within the alloy structure, precipitates change in the process of GPB (Guiner Preston Bagalysky) (1) Zone → GPB (2) Zone (S ”phase) → S ′ phase → S phase (Al ₂ CuMg) As a result, an S phase (Al ₂ CuMg), which is a stable phase, is formed.When solute elements such as Cu and Mg that are dissolved in the Al matrix are precipitated by heat exposure, As the amount of solute elements such as Cu and Mg dissolved in the solution decreases, the conductivity of the precipitation hardened aluminum alloy member increases, and when the heat exposure temperature increases, Melted Since the precipitation of solute elements such as Cu and Mg is promoted, the decrease in the amount of solute elements such as Cu and Mg dissolved in the Al matrix is greatly increased. Thus, the conductivity of the precipitation hardening type aluminum alloy member changes mainly due to the solid solution amount of the solute element in the Al matrix.

  The conductivity of the precipitation hardening type aluminum alloy member can be measured by a general method for measuring the conductivity of a metal material. Since the conductivity of the precipitation hardening type aluminum alloy member can be measured nondestructively, it is preferably measured by an eddy current type conductivity measurement method. If it is an eddy current type conductivity measuring method, it can be measured even at the site where the precipitation hardening type aluminum alloy member is provided.

  In the heat exposure temperature estimation step (S12), the amount of change in electrical conductivity and the heat exposure time before and after the heat exposure in the precipitation hardening type aluminum alloy member, the same composition as the precipitation hardening type aluminum alloy member obtained in advance and a known heat This is a step of estimating the heat exposure temperature of the precipitation hardening aluminum alloy member by comparing the amount of change in electrical conductivity before and after heat exposure and the heat exposure time in the exposed precipitation hardening aluminum alloy.

  The relationship between the amount of change in conductivity before and after heat exposure in a precipitation hardened aluminum alloy that has been subjected to a known heat exposure with the same composition as the precipitation hardening aluminum alloy member in advance, and the relationship between the heat exposure time and the like are determined by experiments, for example, Create a master curve. The heat exposure of the precipitation hardening type aluminum alloy may be performed, for example, at a plurality of heat exposure temperatures assumed in the analysis or the like from the operation of the apparatus provided with the precipitation hardening type aluminum alloy member. For example, when the precipitation hardening type aluminum alloy member may be exposed to any one of the heat exposure temperatures of 100 ° C., 120 ° C., 140 ° C., 160 ° C., 180 ° C., and 200 ° C. from the operation of the apparatus, Heat exposure may be performed at these temperatures. And the heat exposure temperature of a precipitation hardening type aluminum alloy member is estimated from the variation | change_quantity of the electrical conductivity before and behind heat exposure in a precipitation hardening type aluminum alloy member, and heat exposure time.

  FIG. 3 is a model diagram showing a method for estimating the heat exposure temperature. In FIG. 3, the horizontal axis represents the heat exposure time, the vertical axis represents the amount of change in conductivity, and the amount of change in conductivity is indicated by a solid line. Moreover, it is shown that the heat exposure temperature T1 is higher than the heat exposure temperature T2. For example, when the amount of change in conductivity before and after heat exposure in the precipitation hardening type aluminum alloy member is ΔE1, and the heat exposure time is t1, the heat exposure temperature is estimated to be T1. When the conductivity of the precipitation hardening type aluminum alloy member before and after heat exposure is ΔE2 and the heat exposure time is t2, the heat exposure temperature is estimated to be T2. Thus, the heat exposure temperature of the precipitation hardening type aluminum alloy member is estimated.

  In addition, when the heat exposure temperature is estimated based on the amount of change in conductivity before and after heat exposure, the tempering state or processing state of the precipitation hardening aluminum alloy member before heat exposure (unexposed) is different. But the same master curve can be used to estimate the heat exposure temperature. More specifically, even in the case of precipitation hardened aluminum alloy members that are formed of a precipitation hardening aluminum alloy having the same composition and have different heat treatment conditions and processing conditions, the estimation is based on the amount of change in conductivity before and after thermal exposure. Therefore, the effect before heat exposure can be eliminated. This makes it possible to estimate the heat exposure temperature using the same master curve even in the case of precipitation hardening type aluminum alloy members having different tempering states and processing states.

  Next, a thermal history estimation device for precipitation hardening type aluminum alloy members will be described. FIG. 4 is a block diagram showing the configuration of the thermal history estimation device 10 for precipitation hardening type aluminum alloy members. Precipitation hardening type aluminum alloy member thermal history estimation device 10 includes conductivity measuring means 12, control means 14, and output means 16.

  The conductivity measuring means 12 has a function of measuring the conductivity before and after thermal exposure in the precipitation hardening type aluminum alloy member. The conductivity measuring means 12 is composed of an eddy current conductivity measuring device or the like.

  The control means 14 has a heat exposure temperature estimation means 18 and a storage means 20. The control means 14 is comprised by the general personal computer etc., for example.

  The heat exposure temperature estimation means 18 performs the known heat exposure with the same composition as the precipitation hardening type aluminum alloy member obtained in advance and the amount of change in conductivity and the heat exposure time before and after the heat exposure in the precipitation hardening type aluminum alloy member. It has the function of estimating the heat exposure temperature of a precipitation hardening type aluminum alloy member by comparing the amount of change in conductivity and the heat exposure time before and after heat exposure in the received precipitation hardening type aluminum alloy.

  The storage means 20 is a precipitation hardening that has been subjected to a known heat exposure with the same composition as the precipitation hardening type aluminum alloy member obtained in advance and the amount of change in conductivity and the heat exposure time before and after the heat exposure in the precipitation hardening type aluminum alloy member. It has a function of storing data such as a master curve indicating the relationship between the amount of change in electrical conductivity and the heat exposure time before and after heat exposure and the relationship between the amount of change in electrical conductivity and the heat exposure time.

  The output means 16 has a function of outputting the estimated heat exposure temperature of the precipitation hardening type aluminum alloy member. The output means 16 is composed of a display, a printer or the like.

  As described above, according to the above configuration, the precipitation hardening type aluminum alloy member is estimated by estimating the heat exposure temperature of the precipitation hardening type aluminum alloy member from the amount of change in conductivity and the heat exposure time before and after the heat exposure in the precipitation hardening type aluminum alloy member. Since the information is obtained directly from the alloy member and estimated, the heat exposure temperature can be estimated more accurately.

[Second Embodiment]
Next, a second embodiment of the present invention will be described in detail with reference to the drawings. In addition, about the structure similar to 1st embodiment, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted. FIG. 5 is a flowchart showing a thermal history estimation method for a precipitation hardening type aluminum alloy member. The thermal history estimation method of the precipitation hardening type aluminum alloy member includes a conductivity measurement step (S10), a hardness measurement step (S20), a D value calculation step (S22), a heat exposure temperature estimation step (S24), It has.

  The conductivity measurement step (S10) is a step of measuring the conductivity before and after thermal exposure in the precipitation hardening type aluminum alloy member. Since the conductivity measurement step (S10) is the same as the conductivity measurement step (S10) of the first embodiment, detailed description thereof is omitted.

  The hardness measurement step (S20) is a step of measuring the hardness of the precipitation hardening aluminum alloy member before and after thermal exposure. The hardness of the precipitation hardening type aluminum alloy member is mainly influenced by the form of the precipitate of the precipitation hardening type aluminum alloy.

  FIG. 6 is a model diagram showing the relationship between hardness and heat exposure time in a precipitation hardening type aluminum alloy member. In the model diagram of FIG. 6, the horizontal axis indicates the heat exposure time, the vertical axis indicates the hardness, and the change in hardness is indicated by a solid line. Moreover, it is shown that the heat exposure temperature T1 is higher than the heat exposure temperature T2.

  When the heat exposure temperature is a relatively low temperature T2 (for example, 140 ° C. or less), the hardness of the precipitation hardening type aluminum alloy member is substantially constant at the beginning of the heat exposure, and after a predetermined heat exposure time has elapsed. Start to decline. Further, when the heat exposure temperature is a relatively high temperature T1 (for example, 160 ° C. or higher), the hardness of the precipitation hardening type aluminum alloy member gradually decreases from the initial stage of the heat exposure, and the predetermined heat exposure time is reached. The decrease increases after the passage. As described above, the hardness of the precipitation hardening type aluminum alloy decreases more rapidly as the heat exposure temperature becomes higher, and the degree of decrease increases.

  When precipitation hardened aluminum alloy members are exposed to heat, solute elements dissolved in the Al matrix phase precipitate, increasing the metastable phase and changing the metastable phase form. Is formed. The hardness of the precipitation hardening type aluminum alloy member becomes substantially constant while the metastable phase is precipitated as a precipitate, and tends to decrease when the stable phase is precipitated as a precipitate. The hardness of the precipitation hardening type aluminum alloy member tends to further decrease due to Ostwald growth or the like even after the stable phase is precipitated. In addition, the hardness of the precipitation hardening type aluminum alloy member is such that when the heat exposure temperature is relatively low (for example, a heat exposure temperature of 140 ° C. or lower), the metastable phase precipitation rate and the change in form are slow, Since it becomes difficult to shift to a stable phase, it tends to be substantially constant even if the heat exposure time is long.

For example, when the precipitation hardening type aluminum alloy member is formed of an Al-Cu-Mg alloy, the hardness of the precipitation hardening type aluminum alloy member is GPB (1) zone, GPB (2) zone (S " Phase) and the metastable phase consisting of the S ′ phase are substantially constant while being precipitated as precipitates, but tends to decrease when the stable phase consisting of the S phase (Al ₂ CuMg) is precipitated as precipitates. As described above, the hardness of the precipitation hardening type aluminum alloy member changes mainly due to the form of the precipitate.

  For the hardness measurement, for example, a Vickers hardness measurement method such as a micro Vickers hardness measurement method, a Rockwell hardness measurement method, a Brinell hardness measurement method, a Knoop hardness measurement method, or the like can be used. The hardness measurement may be performed by directly measuring a precipitation hardening type aluminum alloy member, or by cutting a sample and filling it with a resin and polishing it with an abrasive such as water-resistant abrasive paper, alumina, or colloidal silica. . Further, the hardness measurement is preferably performed by a micro Vickers hardness measurement method. According to the micro Vickers hardness measurement method, since the indentation size is small, the hardness can be measured at a plurality of locations even if the precipitation hardening type aluminum alloy member is small.

  In the D value calculation step (S22), the amount of change in conductivity before and after thermal exposure in the precipitation hardening aluminum alloy member and the amount of change in hardness before and after heat exposure in the precipitation hardening aluminum alloy member are variables. This is a step of calculating a D value based on the equation.

  The electrical conductivity of the precipitation hardening type aluminum alloy member is mainly due to the amount of solute elements dissolved in the Al matrix, and the solute elements in the Al matrix are precipitated by heat exposure. The amount of solute elements in the Al matrix changes as the amount of solute decreases. From this, the electrical conductivity of the precipitation hardening type aluminum alloy member tends to increase in the degree of change from the initial stage of heat exposure. On the other hand, the conductivity of the precipitation-hardening type aluminum alloy member, when almost all the solute elements dissolved in the Al matrix phase are precipitated, the amount of solute elements in the Al matrix phase decreases, so the degree of change is small. There is a tendency to become smaller.

  Since the hardness of the precipitation hardening type aluminum alloy member is mainly due to the form of the precipitate, the degree of change tends to be small at the initial stage of heat exposure in which the metastable phase is precipitated as a precipitate. is there. On the other hand, the hardness of the precipitation hardening type aluminum alloy member tends to increase as the form of the precipitate changes and the stable phase precipitates as the heat exposure time elapses. Further, the hardness of the precipitation hardening type aluminum alloy member tends to increase in degree due to Ostwald growth or the like even after the stable phase is formed.

  Therefore, by using as a parameter the D value based on the relational expression in which the amount of change in conductivity and the amount of change in hardness are variables, in the period when the degree of change in hardness at the initial stage of heat exposure is small, In the period in which the D value changes due to the change in conductivity, the heat exposure time becomes longer, and the degree of change in conductivity becomes smaller, the D value changes mainly due to the change in hardness. Thus, by using the D value as a parameter, the heat exposure temperature of the precipitation hardening aluminum alloy member can be accurately estimated over the entire period of the heat exposure.

  The D value may be calculated as D = (ΔH + 100) / (ΔE + 100), where ΔE is the amount of change in conductivity before and after heat exposure, and ΔH is the amount of change in hardness before and after heat exposure. This is because setting the D value to such a simple parameter makes it easy to estimate the heat exposure temperature of the precipitation hardening type aluminum alloy member.

  FIG. 7 is a model diagram showing the relationship between the D value, the heat exposure time, and the heat exposure temperature. In the model diagram of FIG. 7, the horizontal axis represents the heat exposure time, the vertical axis represents the D value, and the D value is indicated by a solid line. Note that the heat exposure temperature T1 is higher than the heat exposure temperature T2. Further, in the model diagram of FIG. 7, the conductivity is obtained by using the model diagram showing the relationship between the conductivity and the heat exposure time in FIG. 2 and the model diagram showing the relationship between the hardness and the heat exposure time in FIG. D is calculated by D = (ΔH + 100) / (ΔE + 100) where ΔE is the amount of change in Δ and ΔH is the amount of change in hardness.

  In this case, in the initial stage of heat exposure, the D value gradually decreases as the heat exposure time elapses because the hardness decreases substantially or gently and the conductivity gradually increases. And if heat exposure time passes further, since hardness will fall further and electrical conductivity will become larger, the fall of D value will become large. Thus, the D value varies depending on the heat exposure time. Further, the D values at the heat exposure temperatures T1 and T2 show different changes with respect to the heat exposure time.

  The heat exposure temperature estimation step (S24) is a precipitation hardening type that has been subjected to a known heat exposure with the same composition as the precipitation hardening type aluminum alloy member obtained in advance and the D value and heat exposure time of the precipitation hardening type aluminum alloy member. This is a step of estimating the heat exposure temperature of the precipitation hardening type aluminum alloy member by comparing the D value of the aluminum alloy and the heat exposure time.

  The relationship between the D value of a precipitation hardening aluminum alloy having the same composition as that of the precipitation hardening aluminum alloy member, which has been subjected to known heat exposure, and the heat exposure time is obtained through experiments or the like. For example, a master curve as shown in FIG. Create The heat exposure of the precipitation hardening type aluminum alloy may be performed, for example, at a plurality of heat exposure temperatures assumed in the analysis or the like from the operation of the apparatus provided with the precipitation hardening type aluminum alloy member. And the heat exposure temperature of a precipitation hardening type aluminum alloy member is estimated from D value and the heat exposure time of a precipitation hardening type aluminum alloy member.

  FIG. 8 is a model diagram showing a method for estimating the heat exposure temperature. The model diagram of FIG. 8 shows a method for estimating the heat exposure temperature of the precipitation hardening aluminum alloy member using the model diagram of FIG. For example, when the D value of the precipitation-hardened aluminum alloy member exposed to heat is D1, and the heat exposure time is t1, the heat exposure temperature is estimated to be T1. Further, when the D value of the precipitation-hardened aluminum alloy member exposed to heat is D2, and the heat exposure time is t2, the heat exposure temperature is estimated to be T2. Thus, the heat exposure temperature of the precipitation hardening type aluminum alloy member is estimated.

  Next, a thermal history estimation device for precipitation hardening type aluminum alloy members will be described. FIG. 9 is a block diagram showing a configuration of the thermal history estimator 22 for precipitation hardening type aluminum alloy members. Precipitation hardening type aluminum alloy member thermal history estimation device 22 includes conductivity measuring means 12, hardness measuring means 24, control means 26, and output means 28.

  The conductivity measuring means 12 has a function of measuring the conductivity before and after thermal exposure in the precipitation hardening type aluminum alloy member. Since the conductivity measuring means 12 is the same as the conductivity measuring means 12 of the first embodiment, a detailed description is omitted.

  The hardness measuring means 24 has a function of measuring the hardness of the precipitation hardening type aluminum alloy member before and after thermal exposure. The hardness measuring means 24 includes a Vickers hardness tester, a Rockwell hardness tester, a Brinell hardness tester, a Knoop hardness tester, an ultrasonic hardness tester, and the like.

  The control unit 26 includes a D value calculation unit 30, a heat exposure temperature estimation unit 32, and a storage unit 34. The control means 26 is composed of, for example, a general personal computer.

  The D value calculation means 30 is a relational expression in which the amount of change in conductivity before and after thermal exposure in the precipitation hardening type aluminum alloy member and the amount of change in hardness before and after heat exposure in the precipitation hardening type aluminum alloy member are variables. It has a function to calculate the D value based on it.

  The heat exposure temperature estimation means 32 calculates the amount of change in conductivity and the heat exposure time before and after the heat exposure in the precipitation hardening aluminum alloy member, and the known heat exposure with the same composition as the precipitation hardening aluminum alloy member obtained in advance. It has the function of estimating the heat exposure temperature of a precipitation hardening type aluminum alloy member by comparing the amount of change in conductivity and the heat exposure time before and after heat exposure in the received precipitation hardening type aluminum alloy.

  The storage means 34 is a precipitation hardening type aluminum alloy member obtained in advance, the amount of change in electrical conductivity before and after heat exposure in the precipitation hardening type aluminum alloy member, the amount of change in hardness before and after heat exposure, the D value and the heat exposure time. Change in conductivity before and after heat exposure, change in hardness before and after heat exposure, D value and heat exposure time, D value and heat exposure time It has a function of storing data such as a master curve indicating the relationship.

  The output means 28 has a function of outputting the estimated heat exposure temperature of the precipitation hardening type aluminum alloy member. The output means 28 is composed of a display, a printer or the like.

  As described above, according to the above configuration, the heat exposure temperature of the precipitation hardening type aluminum alloy member based on the amount of change in conductivity before and after heat exposure in the precipitation hardening type aluminum alloy member and the amount of change in hardness before and after heat exposure. Since the information is directly obtained and estimated from the precipitation hardening type aluminum alloy member, it is possible to estimate the heat exposure temperature with higher accuracy.

[Example 1]
A case where the heat exposure temperature is estimated in a compressor impeller used for a supercharger or the like will be described. The compressor impeller is formed of 2014 alloy (tempered state T6: artificial aging treatment after solution treatment) which is an Al—Cu—Mg alloy. The compressor impeller is thermally exposed at a substantially constant temperature between 120 ° C and 200 ° C. First, the creation of a master curve for estimating the heat exposure temperature of the compressor impeller will be described.

  For the master curve specimen, a 2014 alloy material (tempered state T6) having the same composition as the compressor impeller was exposed to 120 ° C., 140 ° C., 160 ° C., 180 ° C., and 200 ° C. heat exposure temperatures and predetermined heat exposure times. The ones exposed to heat and the unexposed ones were used.

  About the test piece for master curves, the electrical conductivity before and behind heat exposure was measured at room temperature. The conductivity measurement was performed by an eddy current type conductivity measurement method. As a measuring device, Sigma tester autoSigma 3000 (eddy current type) manufactured by GE was used.

  A master curve showing the relationship between the amount of change in conductivity before and after thermal exposure, the thermal exposure time, and the thermal exposure temperature was prepared. FIG. 10 is a graph showing a master curve. In the graph of FIG. 10, the horizontal axis represents the heat exposure time, the vertical axis represents the change in conductivity, the white rhombus at 120 ° C., the white square at 140 ° C., the black triangle at 160 ° C., When the temperature is 180 ° C., a black square is shown, and when it is 200 ° C., a black rhombus. At each heat exposure temperature, the longer the heat exposure time, the higher the conductivity, and the greater the change in conductivity before and after the heat exposure. When the heat exposure time was the same, the higher the heat exposure temperature, the greater the change in conductivity before and after heat exposure. Thus, it became clear that the variation | change_quantity of the electrical conductivity before and behind heat exposure shows a different value for every heat exposure temperature and heat exposure time.

  Next, a method for estimating the heat exposure temperature of the heat-exposed compressor impeller will be described. First, the electrical conductivity before and after thermal exposure in the compressor impeller is measured by an eddy current conductivity measurement method. Then, the amount of change in conductivity before and after heat exposure in the compressor impeller is calculated. The heat exposure temperature of the compressor impeller is estimated by using the master curve shown in FIG. 10 as data of the change in conductivity before and after the heat exposure and the heat exposure time in the master curve specimen obtained in advance. For example, when the amount of change in conductivity before and after heat exposure in a compressor impeller is 6 (% IACS) and the heat exposure time is 100 hours, the heat exposure temperature is estimated to be about 200 ° C. from the master curve in FIG. The

[Example 2]
Next, as a master curve, using the D value based on the relational expression with the amount of change in conductivity before and after heat exposure and the amount of change in hardness before and after heat exposure as variables, the heat exposure temperature of the compressor impeller is calculated. A case of estimation will be described. First, a method for creating a master curve will be described. In addition, about the variation | change_quantity of the electrical conductivity before and behind heat exposure, the data of the specimen for master curves in Example 1 were used.

As in Example 1, the master curve specimen was subjected to a heat treatment at 120 ° C., 140 ° C., 160 ° C., 180 ° C., and 200 ° C. with a 2014 alloy material (tempered state T6) having the same composition as the compressor impeller Temperatures, those exposed to heat at a predetermined heat exposure time, and those not exposed were used. The hardness of the specimen for master curve was measured at room temperature. The hardness was measured by a micro Vickers hardness measurement method. For the sample for hardness measurement, a small piece (length 10 mm x width 5 mm x thickness 3 mm ^t ) is cut out from the master curve specimen, filled with resin, and polished to # 2000 with water-resistant abrasive paper (emery paper). did. An AKASHI MVK-Hardness Tester manufactured by Akashi Seisakusho was used as the hardness tester. The test conditions were a load of 1 kgf and a load time of 15 s.

  FIG. 11 is a graph showing the relationship between the amount of change in hardness before and after heat exposure, the heat exposure time, and the heat exposure temperature. In the graph of FIG. 11, the horizontal axis represents the heat exposure time, the vertical axis represents the amount of change in hardness, a white triangle at 120 ° C., a white square at 140 ° C., a black triangle at 160 ° C., When the temperature is 180 ° C., a black square is shown, and when it is 200 ° C., a black rhombus. The longer the heat exposure time, the lower the hardness, and the greater the change in hardness before and after heat exposure. When the heat exposure time was the same, the higher the heat exposure temperature, the greater the amount of change in hardness before and after heat exposure. Furthermore, when the heat exposure temperature was 140 ° C. or lower, the hardness was substantially constant up to about 30 hours.

  D value was calculated | required from the variation | change_quantity (DELTA) E of the electrical conductivity before and behind heat exposure, and the variation | change_quantity (DELTA) H of the hardness before and behind heat exposure. The D value was calculated from the equation D = (ΔH + 100) / (ΔE + 100). And the master curve which shows the relationship between D value, heat exposure time, and heat exposure temperature was created. FIG. 12 is a graph showing a master curve. In the graph of FIG. 12, the horizontal axis represents the heat exposure time, the vertical axis represents the D value, the white rhombus at 120 ° C., the white square at 140 ° C., the black triangle at 160 ° C., and the 180 ° C. The time is indicated by a black square, and the time at 200 ° C. is indicated by a black rhombus. From the graph of FIG. 12, it became clear that D value shows a different value for every heat exposure temperature and heat exposure time.

  Next, a method for estimating the heat exposure temperature in a heat-exposed compressor impeller will be described. The electrical conductivity of the compressor impeller before and after thermal exposure is measured by an eddy current conductivity measurement method. The hardness of the compressor impeller before and after heat exposure is measured by the micro Vickers hardness test method. Then, the change amount ΔE of the conductivity before and after the heat exposure and the change amount ΔH of the hardness before and after the heat exposure are calculated, and the D value is calculated from the equation D = (ΔH + 100) / (ΔE + 100).

  The heat exposure temperature of the compressor impeller is estimated by using the master curve shown in FIG. 12 as data of the D value and heat exposure time of the master curve specimen obtained in advance. For example, when the D value in a heat-exposed compressor impeller is 0.45 and the heat exposure time is 100 hours, the heat exposure temperature is estimated to be about 200 ° C. from the master curve in FIG.

DESCRIPTION OF SYMBOLS 10, 22 Thermal history estimation apparatus 12 Conductivity measurement means 14, 26 Control means 16, 28 Output means 18, 32 Thermal exposure temperature estimation means 20, 34 Storage means 24 Hardness measurement means 30 D value calculation means

Claims (6)

A thermal history estimation method for a precipitation-hardened aluminum alloy member exposed to heat,
A conductivity measuring step for measuring conductivity before and after thermal exposure in the precipitation hardening type aluminum alloy member;
Precipitation hardening type aluminum having the same composition as the precipitation hardening type aluminum alloy member obtained in advance and a known heat exposure, the amount of change in electrical conductivity and the heat exposure time before and after heat exposure in the precipitation hardening type aluminum alloy member A heat exposure temperature estimating step of estimating a heat exposure temperature of the precipitation hardening type aluminum alloy member by comparing a change in conductivity before and after heat exposure in the alloy and a heat exposure time;
A method for estimating the thermal history of a precipitation hardening aluminum alloy member, comprising: It is the thermal history estimation method of the precipitation hardening type aluminum alloy member according to claim 1,
A hardness measurement step for measuring the hardness before and after thermal exposure in the precipitation hardening type aluminum alloy member;
Calculate D value based on relational expression with variable amount of change in conductivity before and after thermal exposure in precipitation hardening aluminum alloy member and change in hardness before and after heat exposure in precipitation hardening aluminum alloy member. A D value calculating step,
With
The heat exposure temperature estimation step includes:
D value and heat exposure time of the precipitation hardening type aluminum alloy member, and D value and heat exposure of the precipitation hardening type aluminum alloy which has been subjected to known heat exposure with the same composition as the precipitation hardening type aluminum alloy member obtained in advance. A method for estimating the thermal history of a precipitation hardening type aluminum alloy member, comprising comparing the time and the heat exposure temperature of the precipitation hardening type aluminum alloy member. It is the thermal history estimation method of the precipitation hardening type aluminum alloy member according to claim 1 or 2,
The method for estimating thermal history of a precipitation hardening type aluminum alloy member, wherein the conductivity measuring step is measured by an eddy current type conductivity measuring method. It is the thermal history estimation method of the precipitation hardening type aluminum alloy member according to claim 2 or 3,
The method for estimating the heat history of a precipitation hardening type aluminum alloy member, wherein the hardness measurement step is performed by a Vickers hardness measurement method, a Rockwell hardness measurement method, a Brinell hardness measurement method, or a Knoop hardness measurement method. A thermal history estimation device for a precipitation-hardened aluminum alloy member exposed to heat,
Conductivity measuring means for measuring conductivity before and after thermal exposure in the precipitation hardening type aluminum alloy member;
Precipitation hardening type aluminum having the same composition as the precipitation hardening type aluminum alloy member obtained in advance and a known heat exposure, the amount of change in electrical conductivity and the heat exposure time before and after heat exposure in the precipitation hardening type aluminum alloy member A thermal exposure temperature estimation means for estimating a thermal exposure temperature of the precipitation hardened aluminum alloy member by comparing a change in conductivity before and after thermal exposure in the alloy and a thermal exposure time;
A thermal history estimation device for a precipitation hardening type aluminum alloy member, comprising: It is the thermal history estimation apparatus of the precipitation hardening type aluminum alloy member according to claim 5,
Hardness measuring means for measuring the hardness before and after thermal exposure in the precipitation hardening type aluminum alloy member;
Calculate D value based on relational expression with variable amount of change in conductivity before and after thermal exposure in precipitation hardening aluminum alloy member and change in hardness before and after heat exposure in precipitation hardening aluminum alloy member. D value calculating means for
With
The thermal exposure temperature estimation means includes
D value and heat exposure time of the precipitation hardening type aluminum alloy member, and D value and heat exposure of the precipitation hardening type aluminum alloy which has been subjected to known heat exposure with the same composition as the precipitation hardening type aluminum alloy member obtained in advance. A thermal history estimation device for a precipitation hardening type aluminum alloy member, wherein the heat exposure temperature of the precipitation hardening type aluminum alloy member is estimated by comparing the time.

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