JP6759713B2 - Thermal history estimation method and thermal history estimation device for precipitation hardening aluminum alloy members - Google Patents

Description

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

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

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

Japanese Unexamined Patent Publication No. 2012-2231

By the way, in the method of estimating the heat exposure temperature by measuring the ambient temperature around the precipitation hardening aluminum alloy member as described above, since the information is not directly obtained from the precipitation hardening aluminum alloy member, the precipitation hardening aluminum alloy It may not be possible to accurately estimate the heat exposure temperature of the member.

Therefore, an object of the present invention is to provide a thermal history estimation method and a thermal history estimation device for a precipitation hardening aluminum alloy member capable of more accurately estimating the heat exposure temperature of the heat-exposed precipitation hardening aluminum alloy member. It is to be.

The method for estimating the thermal history of a precipitation-curable aluminum alloy member according to the present invention is a method for estimating the thermal history of a heat-exposed precipitation-curable aluminum alloy member, and the conductivity of the precipitation-curable aluminum alloy member before and after heat exposure. It is known that the conductivity measuring step for measuring the above, the amount of change in conductivity and the heat exposure time before and after heat exposure of the precipitation-curable aluminum alloy member, and the same composition as that of the precipitation-curable aluminum alloy member obtained in advance. Heat exposure temperature estimation step for estimating the heat exposure temperature of the precipitation-curable aluminum alloy member by comparing the amount of change in conductivity before and after heat exposure and the heat exposure time of the heat-exposed precipitation-curable aluminum alloy. It is characterized by having.

In the method for estimating the thermal history of a precipitation-curable aluminum alloy member according to the present invention, a hardness measuring step of measuring the hardness of the precipitation-curable aluminum alloy member before and after heat exposure and heat exposure of the precipitation-curable aluminum alloy member. A D value calculation step 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 of the precipitation-curable aluminum alloy member before and after heat exposure as variables is provided. The heat exposure temperature estimation step is a precipitation-hardening type in which the D value and the heat exposure time of the precipitation-hardening type aluminum alloy member and a known heat-exposure having the same composition as the precipitation-hardening type aluminum alloy member obtained in advance are received. It is characterized in that the heat exposure temperature of the precipitation-hardened aluminum alloy member is estimated by comparing the D value of the aluminum alloy and the heat exposure time.

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

In the method for estimating the thermal history of a precipitation-curable aluminum alloy member according to the present invention, the hardness measuring step is measured by a Vickers hardness measuring method, a Rockwell hardness measuring method, a Brinell hardness measuring method, or a Noupe hardness measuring method. It is characterized by that.

The heat history estimation device for the precipitation-curable aluminum alloy member according to the present invention is a heat history estimation device for the heat-exposed precipitation-curable aluminum alloy member, and the conductivity of the precipitation-curable aluminum alloy member before and after heat exposure. It is known that the conductivity measuring means for measuring the above, the amount of change in conductivity and the heat exposure time before and after heat exposure of the precipitation-curable aluminum alloy member, and the same composition as the predetermined precipitation-curable aluminum alloy member. Heat exposure temperature estimation means for estimating the heat exposure temperature of the precipitation-curable aluminum alloy member by comparing the amount of change in conductivity and the heat exposure time before and after heat exposure in the heat-exposed precipitation-curable aluminum alloy. It is characterized by having.

In the thermal history estimation device of the precipitation-curable aluminum alloy member according to the present invention, a hardness measuring means for measuring the hardness of the precipitation-curable aluminum alloy member before and after heat exposure and heat exposure of the precipitation-curable aluminum alloy member. A D value calculating 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 of the precipitation-curable aluminum alloy member before and after heat exposure as variables is provided. The heat exposure temperature estimation means is a precipitation-curing type that has received a known heat exposure having the same composition as the precipitation-hardening type aluminum alloy member, which has the same composition as the D value and heat exposure time of the precipitation-hardening type aluminum alloy member. It is characterized in that the heat exposure temperature of the precipitation-hardened aluminum alloy member is estimated by comparing the D value of the aluminum alloy and the heat exposure time.

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

It is a flowchart which shows the thermal history estimation method of the precipitation hardening type aluminum alloy member in 1st Embodiment of this invention. It is a model figure which shows the relationship between the conductivity and the heat exposure time in the precipitation hardening type aluminum alloy member in the 1st Embodiment of this invention. It is a model diagram which shows the method of estimating the heat exposure temperature in the 1st Embodiment of this invention. It is a block diagram which shows the structure of the thermal history estimation apparatus of the precipitation hardening type aluminum alloy member in the 1st Embodiment of this invention. It is a flowchart which shows the thermal history estimation method of the precipitation hardening type aluminum alloy member in the 2nd Embodiment of this invention. It is a model figure which shows the relationship between the hardness and the heat exposure time in the precipitation hardening type aluminum alloy member in the 2nd Embodiment of this invention. It is a model figure which shows the relationship between the D value, the heat exposure time, and the heat exposure temperature in the 2nd Embodiment of this invention. It is a model diagram which shows the method of estimating the heat exposure temperature in the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the thermal history estimation apparatus of the precipitation hardening type aluminum alloy member in the 2nd Embodiment of this invention. It is a graph which shows the master curve in Example 1 of this invention. It is a graph which shows the relationship between the amount of change of hardness before and after heat exposure, heat exposure time, and heat exposure temperature in Example 2 of this invention. It is a graph which shows the master curve in Example 2 of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

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

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

The precipitation hardening aluminum alloy member is formed of a precipitation hardening aluminum alloy such as JIS standard. The precipitation-hardening type aluminum alloy is an aluminum alloy in which precipitates are precipitated and strengthened by a solution treatment and then an aging treatment. Precipitated and cured 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 and the like. (2000 series, 6000 series, 7000 series, AC1B, AC4A, AC4C, AC4CH, etc.).

The conductivity measuring step (S10) is a step of measuring the conductivity of the precipitation hardening aluminum alloy member before and after heat exposure. The conductivity of the precipitation-curable aluminum alloy member is mainly affected by the solid solution amount of the solute element in the Al matrix in the precipitation-curable aluminum alloy. When the precipitation-curable aluminum alloy member is exposed to heat, solute elements that are solid-dissolved in the Al matrix are precipitated as precipitates, and the amount of solute elements in the Al matrix is reduced, resulting in precipitation. The conductivity of the curable aluminum alloy member changes. From this, the influence of heat exposure of the precipitation hardening aluminum alloy member can be evaluated by the change in conductivity before and after heat exposure of the precipitation hardening aluminum alloy member.

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

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

The precipitation hardening aluminum alloy member is strengthened by precipitating a precipitate composed of a metastable phase by an aging treatment after the solution heat treatment. When the precipitation-curable aluminum alloy member is exposed to heat, solute elements that are solid-solved in the Al matrix are precipitated, the metastable phase increases, the morphology of the metastable phase changes, and finally the stable phase. Is formed. When a solute element dissolved in the Al matrix is precipitated by heat exposure, the amount of the solute element dissolved in the Al matrix is reduced, so that the conductivity of the precipitation-curable aluminum alloy member is reduced. Tends to increase. Further, when the heat exposure temperature becomes high, the precipitation of the solute element dissolved in the Al matrix is promoted, so that the amount of the solute element dissolved in the Al matrix is further reduced. Therefore, the conductivity of the precipitation-curable aluminum alloy member tends to be higher.

For example, when the precipitation-curable aluminum alloy member is formed of an Al—Cu—Mg-based alloy, solute elements such as Cu and Mg that are solid-dissolved in the Al matrix are precipitated by heat exposure. In the alloy structure, the precipitate changes in the process of GPB (Guinier Preston Bagayatsky) (1) zone → GPB (2) zone (S “phase) → S'phase → S phase (Al ₂ CuMg). Finally, the stable phase S phase (Al ₂ CuMg) is formed. When solute elements such as Cu and Mg that are solid-dissolved in the Al matrix are precipitated by heat exposure, the Al matrix contains the solute elements. Since the amount of solute elements such as Cu and Mg that are solid-dissolved in the aluminum decreases, the conductivity of the precipitation-curable aluminum alloy member increases. Further, when the heat exposure temperature increases, it solidifies in the Al matrix. Since the precipitation of dissolved solute elements such as Cu and Mg is promoted, the amount of solute elements such as Cu and Mg dissolved in the Al matrix is greatly reduced, and the precipitation-curable aluminum The conductivity of the alloy member increases. As described above, the conductivity of the precipitation-curable 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 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 aluminum alloy member can be measured non-destructively, it is preferably measured by the eddy current conductivity measuring method. If it is an eddy current type conductivity measuring method, it can be measured even at a site where a precipitation hardening aluminum alloy member is provided.

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

The relationship between the amount of change in conductivity before and after heat exposure in a precipitation hardening aluminum alloy having the same composition as the precipitation hardening aluminum alloy member and the known heat exposure and the heat exposure time can be obtained by experiments or the like, for example. Create a master curve, etc. The heat exposure of the precipitation hardening aluminum alloy may be performed at a plurality of heat exposure temperatures assumed in the operation and analysis of the apparatus provided with the precipitation hardening aluminum alloy member, for example. For example, if the precipitation hardening aluminum alloy member may be exposed to a heat exposure temperature of 100 ° C., 120 ° C., 140 ° C., 160 ° C., 180 ° C., or 200 ° C. from the operation of the device, Heat exposure may be sufficient at these temperatures. Then, the heat exposure temperature of the precipitation hardening aluminum alloy member is estimated from the amount of change in conductivity before and after heat exposure and the heat exposure time of the precipitation hardening aluminum alloy member.

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. Further, the heat exposure temperature T1 indicates that the temperature is higher than the heat exposure temperature T2. For example, when the amount of change in conductivity of the precipitation hardening aluminum alloy member before and after heat exposure 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 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. In this way, the heat exposure temperature of the precipitation hardening 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 tempered state and processed state of the precipitation hardening aluminum alloy member before heat exposure (unexposed) are different. However, the same master curve can be used to estimate the heat exposure temperature. More specifically, it is estimated based on the amount of change in conductivity before and after heat exposure even in the case of precipitation hardening aluminum alloy members which are formed of precipitation hardening aluminum alloys having the same composition and have different heat treatment conditions and processing conditions. Therefore, the effects before heat exposure can be excluded. This makes it possible to estimate the heat exposure temperature using the same master curve even in the case of precipitation hardening aluminum alloy members having different tempered states, processed states, and the like.

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

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

The control means 14 includes a heat exposure temperature estimation means 18 and a storage means 20. The control means 14 is composed of, for example, a general personal computer or the like.

The heat exposure temperature estimating means 18 determines the amount of change in conductivity and heat exposure time of the precipitation-curable aluminum alloy member before and after heat exposure, and the heat exposure known in advance with the same composition as that of the precipitation-curable aluminum alloy member. It has a function of estimating the heat exposure temperature of the precipitation-curable aluminum alloy member by comparing the amount of change in conductivity and the heat exposure time of the received precipitation-curable aluminum alloy before and after heat exposure.

The storage means 20 is subjected to known heat exposure with the same composition as the previously determined precipitation-curable aluminum alloy member, such as the amount of change in conductivity and heat exposure time before and after heat exposure of the precipitation-curable aluminum alloy member. It has a function to store data such as a master curve showing the relationship between the amount of change in conductivity and the heat exposure time before and after heat exposure in the type aluminum alloy, the amount of change in conductivity and the heat exposure time.

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

As described above, according to the above configuration, precipitation hardening aluminum by estimating the heat exposure temperature of the precipitation hardening aluminum alloy member from the amount of change in conductivity before and after heat exposure and the heat exposure time of the precipitation hardening aluminum alloy member. Since the estimation is made by directly obtaining information from the alloy member, it is possible to estimate the heat exposure temperature more accurately.

[Second Embodiment]
Next, the second embodiment of the present invention will be described in detail with reference to the drawings. The same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. FIG. 5 is a flowchart showing a method for estimating the thermal history of the precipitation hardening aluminum alloy member. The thermal history estimation method for the precipitation-curable aluminum alloy member includes a conductivity measurement step (S10), a hardness measurement step (S20), a D value calculation step (S22), and a heat exposure temperature estimation step (S24). It has.

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

The hardness measuring step (S20) is a step of measuring the hardness of the precipitation hardening aluminum alloy member before and after heat exposure. The hardness of the precipitation hardening aluminum alloy member is mainly affected by the morphology of the precipitation hardening aluminum alloy deposits.

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

When the heat exposure temperature is relatively low temperature T2 (for example, 140 ° C. or lower), the hardness of the precipitation hardening aluminum alloy member is substantially constant at the initial stage of heat exposure, and after a predetermined heat exposure time elapses. Starts 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 aluminum alloy member gradually decreases from the initial stage of heat exposure, and the predetermined heat exposure time is reached. After the lapse of time, the decrease becomes large. As described above, the hardness of the precipitation hardening aluminum alloy decreases faster as the heat exposure temperature becomes higher, and the degree of decrease increases.

When the precipitation-curable aluminum alloy member is exposed to heat, solute elements that are solid-solved in the Al matrix are precipitated, the metastable phase increases, the morphology of the metastable phase changes, and finally the stable phase. Is formed. The hardness of the precipitation-curable aluminum alloy member tends to be 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 aluminum alloy member tends to further decrease due to Ostwald growth or the like even after the stable phase is precipitated. Further, regarding the hardness of the precipitation-curable aluminum alloy member, when the heat exposure temperature is relatively low (for example, the heat exposure temperature of 140 ° C. or lower), the precipitation rate and morphological change of the metastable phase become slow. Since it becomes difficult to shift to the stable phase, it tends to be substantially constant even if the heat exposure time is long.

For example, when the precipitation-curing aluminum alloy member is formed of an Al—Cu—Mg-based alloy, the hardness of the precipitation-curing aluminum alloy member is GPB (1) zone, GPB (2) zone (S ”. It is substantially constant while the semi-stable phase composed of the phase) and the S'phase is precipitated as a precipitate, but tends to decrease when the stable phase composed of the S phase (Al ₂ CuMg) is precipitated as a precipitate. As described above, the hardness of the precipitation-curable aluminum alloy member changes mainly due to the morphology of the precipitate.

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

In the D value calculation step (S22), the relationship between the amount of change in conductivity of the precipitation-curable aluminum alloy member before and after heat exposure and the amount of change in hardness of the precipitation-curable aluminum alloy member before and after heat exposure are used as variables. This is a step of calculating the D value based on the formula.

The conductivity of the precipitation-curable 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. , It changes as the amount of solute element dissolved in the Al matrix decreases. For this reason, the conductivity of precipitation hardening aluminum alloy members tends to change significantly from the initial stage of heat exposure. On the other hand, the conductivity of the precipitation-curable aluminum alloy member changes with respect to the degree of change because the amount of solute elements in the Al matrix decreases when most of the solute elements dissolved in the Al matrix are precipitated. It tends to be smaller.

Since the hardness of the precipitation hardening aluminum alloy member is mainly due to the morphology of the precipitate, the degree of change tends to be small in 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 aluminum alloy member tends to increase when the morphology of the precipitate changes with the passage of heat exposure time and a stable phase is precipitated. Further, the hardness of the precipitation hardening aluminum alloy member tends to change greatly due to Ostwald growth or the like even after the stable phase is formed.

Therefore, by using the D value based on the relational expression with the amount of change in conductivity and the amount of change in hardness as variables as parameters, mainly during the period when the degree of change in hardness at the initial stage of heat exposure is small. , The D value changes due to the change in conductivity, the heat exposure time becomes long, and the D value changes mainly due to the change in hardness during the period when the degree of change in conductivity becomes small. As described above, by using the D value as a parameter, the heat exposure temperature of the precipitation hardening aluminum alloy member can be accurately estimated during the entire period of 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. By setting the D value to such a simple parameter, it becomes easy to estimate the heat exposure temperature of the precipitation hardening 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. The heat exposure temperature T1 indicates a case where the temperature 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 of FIG. 2 and the model diagram showing the relationship between the hardness and the heat exposure time of FIG. When the amount of change in is ΔE and the amount of change in hardness is ΔH, the D value is calculated by D = (ΔH + 100) / (ΔE + 100).

In this case, the D value gradually decreases with the lapse of the heat exposure time because the hardness is substantially constant or gradually decreases and the conductivity gradually increases in the initial stage of heat exposure. Then, as the heat exposure time elapses further, the hardness is further reduced and the conductivity is further increased, so that the decrease in the D value is large. Thus, the D value changes depending on the heat exposure time. In addition, 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-curing type in which the D value and heat exposure time of the precipitation-curing aluminum alloy member and a known heat-exposure having the same composition as the previously obtained precipitation-curing aluminum alloy member are received. This is a step of estimating the heat exposure temperature of the precipitation-curable aluminum alloy member by comparing the D value of the aluminum alloy and the heat exposure time.

The relationship between the D value of the precipitation hardening aluminum alloy having the same composition as the precipitation hardening aluminum alloy member and the known heat exposure and the heat exposure time was obtained by experiments or the like, and for example, the master curve as shown in FIG. To create. The heat exposure of the precipitation hardening aluminum alloy may be performed at a plurality of heat exposure temperatures assumed in the operation and analysis of the apparatus provided with the precipitation hardening aluminum alloy member, for example. Then, the heat exposure temperature of the precipitation hardening aluminum alloy member is estimated from the D value and the heat exposure time of the precipitation hardening 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 of estimating the heat exposure temperature of the precipitation hardening aluminum alloy member using the model diagram of FIG. 7. For example, when the heat-exposed precipitation hardening aluminum alloy member has a D value of D1 and a heat exposure time of t1, the heat exposure temperature is estimated to be T1. Further, when the D value of the heat-exposed precipitation hardening aluminum alloy member is D2 and the heat exposure time is t2, the heat exposure temperature is estimated to be T2. In this way, the heat exposure temperature of the precipitation hardening aluminum alloy member is estimated.

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

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

The hardness measuring means 24 has a function of measuring the hardness of the precipitation hardening aluminum alloy member before and after heat 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 means 26 includes a D value calculation means 30, a heat exposure temperature estimation means 32, and a storage means 34. The control means 26 is composed of, for example, a general personal computer or the like.

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

The heat exposure temperature estimation means 32 provides known heat exposure with the same composition as the previously determined precipitation-curable aluminum alloy member, the amount of change in conductivity and heat exposure time before and after heat exposure in the precipitation-curable aluminum alloy member. It has a function of estimating the heat exposure temperature of the precipitation-curable aluminum alloy member by comparing the amount of change in conductivity and the heat exposure time of the received precipitation-curable aluminum alloy before and after heat exposure.

The storage means 34 is a precipitation-curable aluminum alloy member having a change in conductivity before and after heat exposure, a change in hardness before and after heat exposure, a D value and a heat exposure time, and a predetermined precipitation-curable aluminum alloy member. The amount of change in conductivity before and after heat exposure, the amount of change in hardness before and after heat exposure, D value and heat exposure time, D value and heat exposure time in a known heat-exposed precipitation-curable aluminum alloy with the same composition as It has a function to store data such as a master curve showing the relationship between.

The output means 28 has a function of outputting the estimated heat exposure temperature of the precipitation hardening aluminum alloy member and the like. 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-curable aluminum alloy member is based on the amount of change in conductivity of the precipitation-curable aluminum alloy member before and after heat exposure and the amount of change in hardness before and after heat exposure. By estimating, the heat exposure temperature can be estimated more accurately because the information is directly obtained from the precipitation-hardened aluminum alloy member.

[Example 1]
A case of estimating the heat exposure temperature in a compressor impeller used for a supercharger or the like will be described. The compressor impeller is formed of a 2014 alloy which is an Al—Cu—Mg based alloy (conditioning state T6: artificial aging treatment after solution treatment). The compressor impeller is heat 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 specimen for the master curve, a 2014 alloy material (conditioned state T6) having the same composition as the compressor impeller was used at each heat exposure temperature of 120 ° C., 140 ° C., 160 ° C., 180 ° C. and 200 ° C., and a predetermined heat exposure time. The heat-exposed one and the unexposed one were used.

The conductivity of the master curve specimen was measured at room temperature before and after heat exposure. The conductivity was measured by an eddy current conductivity measuring method. As a measuring device, a Sigma tester autoSigma3000 (eddy current type) manufactured by GE was used.

A master curve was created showing the relationship between the amount of change in conductivity before and after heat exposure, the heat exposure time, and the heat exposure temperature. 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 amount of change in conductivity, a white rhombus at 120 ° C, a white quadrangle at 140 ° C, and a black triangle at 160 ° C. The temperature at 180 ° C. is indicated by a black square, and the temperature at 200 ° C. is indicated by a black rhombus. At each heat exposure temperature, the longer the heat exposure time, the greater the conductivity, and the greater the amount of change in conductivity before and after heat exposure. Further, when the heat exposure time was the same, the higher the heat exposure temperature, the larger the change in conductivity before and after the heat exposure. As described above, it was clarified that the amount of change in conductivity before and after heat exposure shows different values depending on the heat exposure temperature and the heat exposure time.

Next, a method of estimating the heat exposure temperature of the heat-exposed compressor impeller will be described. First, the conductivity of the compressor impeller before and after heat exposure is measured by an eddy current conductivity measuring method. Then, the amount of change in the conductivity of the compressor impeller before and after heat exposure is calculated. The heat exposure temperature of the compressor impeller is estimated by using the master curve shown in FIG. 10 as the data of the change in conductivity and the heat exposure time before and after heat exposure in the master curve specimen obtained in advance. For example, when the amount of change in conductivity of the compressor impeller before and after heat exposure 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 of FIG. To.

[Example 2]
Next, as a master curve, the heat exposure temperature of the compressor impeller is set 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 case of estimation will be described. First, a method of creating a master curve will be described. As for the amount of change in conductivity before and after heat exposure, the data of the master curve specimen in Example 1 was used.

Similar to Example 1, a 2014 alloy material (conditioned state T6) having the same composition as the compressor impeller was exposed to heat at 120 ° C., 140 ° C., 160 ° C., 180 ° C., and 200 ° C. on the master curve specimen. Heat-exposed and unexposed ones were used, respectively, at a temperature and a predetermined heat exposure time. The hardness of the master curve specimen was measured at room temperature. The hardness was measured by the 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. As the hardness tester, AKASHI MVK-Hardness Tester manufactured by Akashi Seisakusho was used. 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 quadrangle at 140 ° C., and a black triangle at 160 ° C. The temperature at 180 ° C. is indicated by a black square, and the temperature at 200 ° C. is indicated by a black rhombus. The longer the heat exposure time, the lower the hardness, and the greater the amount of change in hardness before and after heat exposure. In addition, 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. Further, when the heat exposure temperature was 140 ° C. or lower, the hardness was substantially constant up to about 30 hours.

The D value was obtained from the change in conductivity ΔE before and after heat exposure and the change in hardness ΔH before and after heat exposure. The D value was calculated from the formula D = (ΔH + 100) / (ΔE + 100). Then, a master curve showing the relationship between the D value, the heat exposure time, and the heat exposure temperature was created. FIG. 12 is a graph showing a master curve. In the graph of FIG. 12, the horizontal axis is the heat exposure time, the vertical axis is the D value, 120 ° C is a white rhombus, 140 ° C is a white quadrangle, 160 ° C is a black triangle, and 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 was clarified that the D value shows different values depending on the heat exposure temperature and the heat exposure time.

Next, a method for estimating the heat exposure temperature in the heat-exposed compressor impeller will be described. The conductivity of the compressor impeller before and after heat exposure is measured by an eddy current conductivity measuring method. The hardness of the compressor impeller before and after heat exposure is measured by the Micro Vickers hardness test method. Then, the amount of change in conductivity ΔE before and after heat exposure and the amount of change in hardness ΔH before and after heat exposure are calculated, and the D value is calculated from the formula 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 the data of the D value and the heat exposure time of the specimen for the master curve obtained in advance. For example, when the D value of the 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 of FIG.

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

Claims (4)

A method for estimating the thermal history of heat-exposed precipitation hardening aluminum alloy members.
A conductivity measuring step for measuring the conductivity of the precipitation hardening aluminum alloy member before and after heat exposure, and
A hardness measuring step for measuring the hardness of the precipitation hardening aluminum alloy member before and after heat exposure, and
Calculate the D value based on the relational expression with the amount of change in conductivity of the precipitation-hardening aluminum alloy member before and after heat exposure and the amount of change in hardness of the precipitation-hardening aluminum alloy member before and after heat exposure as variables. and D value calculation step of,
The D value and heat exposure time of the precipitation hardening aluminum alloy member, and the D value and heat exposure of the precipitation hardening aluminum alloy that has been subjected to known heat exposure with the same composition as the precipitation hardening aluminum alloy member obtained in advance. A heat exposure temperature estimation step for estimating the heat exposure temperature of the precipitation hardening aluminum alloy member by comparing with time, and
A method for estimating the thermal history of a precipitation hardening aluminum alloy member. The method for estimating the thermal history of a precipitation hardening aluminum alloy member according to claim 1 .
The conductivity measuring step is a method for estimating the thermal history of a precipitation hardening aluminum alloy member, which comprises measuring by an eddy current type conductivity measuring method. The method for estimating the thermal history of a precipitation hardening aluminum alloy member according to claim 1 or 2 .
The hardness measuring step is a method for estimating the thermal history of a precipitation-hardened aluminum alloy member, which comprises measuring by a Vickers hardness measuring method, a Rockwell hardness measuring method, a Brinell hardness measuring method or a Knoop hardness measuring method. A thermal history estimation device for heat-exposed precipitation hardening aluminum alloy members.
A conductivity measuring means for measuring the conductivity of the precipitation hardening aluminum alloy member before and after heat exposure,
A hardness measuring means for measuring the hardness of the precipitation hardening aluminum alloy member before and after heat exposure,
Calculate the D value based on the relational expression with the amount of change in conductivity of the precipitation hardening aluminum alloy member before and after heat exposure and the amount of change in hardness of the precipitation hardening aluminum alloy member before and after heat exposure as variables. and D value calculating means for,
The D value and heat exposure time of the precipitation hardening aluminum alloy member, and the D value and heat exposure of the precipitation hardening aluminum alloy that has been subjected to known heat exposure with the same composition as the precipitation hardening aluminum alloy member obtained in advance. A heat exposure temperature estimating means for estimating the heat exposure temperature of the precipitation hardening aluminum alloy member by comparing with time ,
Thermal history estimator of precipitation hardenable aluminum alloy member, characterized in that it comprises a.

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