Method for testing lag time of vacuum double-chamber furnace for fastener

Abstract

The invention relates to a method for testing the lag time of a vacuum double-chamber furnace for a fastener. The method comprises a test process of calculating the lag time of the fastener by taking heating at a preheating temperature K1 as a starting point. According to the technical scheme, the heating chamber of the vacuum double-chamber furnace is cooled to the preheating temperature K1 from the solid solution temperature, and the fastener enters the heating chamber of the vacuum double-chamber furnace from the preheating temperature K1 to be heated to the solid solution temperature, so that the situation that the heating chamber of the vacuum double-chamber furnace is heated to the solid solution temperature from the room temperature and then cooled to the room temperature is avoided; the problem that in the prior art, the cooling process of a vacuum double-chamber furnace is long in period is solved.

Description

Technical Field

[0001] This invention relates to a method for testing the hysteresis time of fasteners using a vacuum double-chamber furnace, belonging to the field of heat treatment technology. Background Technology

[0002] Fasteners such as bolts or nuts need to be heated to the solution temperature in a vacuum double-chamber furnace. However, when existing vacuum double-chamber furnaces are used (see Chinese patent application publication number CN103952522A), the product is heated from room temperature to the solution temperature and then cooled to room temperature before being removed from the furnace, resulting in a long product cooling cycle. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method for testing the hysteresis time of a vacuum dual-chamber furnace for fasteners.

[0004] The present invention is achieved through the following technical solutions.

[0005] This invention provides a method for testing the hysteresis time of fasteners using a vacuum dual-chamber furnace, comprising: The test process is implemented to calculate the lag time of fasteners starting from the preheating temperature K1.

[0006] The testing process includes step S1: Loading the furnace with the maximum loading capacity, placing the fasteners into the heating chamber of the vacuum double-chamber furnace at room temperature, inserting the test coupler through the rear door of the heating chamber of the vacuum double-chamber furnace, placing the test coupler in the center of the fasteners, and closing the heating chamber; the vacuum double-chamber furnace has a built-in control coupler to monitor the set heating temperature, and the test coupler is used to monitor the actual heating temperature reached by the fasteners.

[0007] The test process also includes step S2: after evacuating the heating chamber, heating is performed, and the heating chamber of the vacuum double chamber furnace is heated to the solid solution temperature K2; observe the control couple temperature curve and the test couple temperature curve, set the preheating temperature K1, with the control couple temperature curve on top and the test couple temperature curve on the bottom, and the holding time T is the time from the beginning of the test couple temperature curve slowing down to the preheating temperature K1. Step S2 of the test process also includes: observing the time T3 when the dipole temperature curve reaches the set solution temperature K2 when heated to the solution temperature K2, and the time T4 when the dipole temperature curve reaches the actual solution temperature K2. The lag time = T4-T3. The time value corresponding to the solution temperature K2 is determined according to the regulations for the start time of heat preservation of different materials. The time T4 is taken as the value corresponding to the lower limit of the actual solution temperature K2. The starting point of the lag time is increased from room temperature to preheating temperature K1.

[0008] Step S3: After the fasteners are heated in the heating chamber of the vacuum double-chamber furnace, they are transferred to the cold chamber to cool and then removed. The next batch of fasteners enters the cold chamber to wait. When the fasteners are preheated to the preheating temperature K1 in the heating chamber of the vacuum double-chamber furnace, they are placed in the heating chamber of the vacuum double-chamber furnace and held at the preheating temperature K1 for a holding time T. Then they are heated from the preheating temperature K1 to the solution temperature.

[0009] The beneficial effects of this invention are as follows: The technical solution adopted in this application realizes that the heating chamber of the vacuum double chamber furnace is cooled from the solution temperature to the preheating temperature K1, and the fasteners are heated to the solution temperature after entering the heating chamber of the vacuum double chamber furnace from the preheating temperature K1. This avoids the situation where the heating chamber of the vacuum double chamber furnace is heated from room temperature to the solution temperature and then cooled back to room temperature, thus solving the problem of long cooling process time of the prior art vacuum double chamber furnace. Attached Figure Description

[0010] Figure 1 This is a time and temperature distribution diagram of the fastener heating according to the present invention; Figure 2 This is a diagram showing the heating time and temperature distribution in an embodiment of the present invention; Figure 3 This is a time and temperature distribution diagram of heating from preheating temperature K1 according to the present invention; Detailed Implementation

[0011] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0012] like Figures 1 to 3 As shown.

[0013] This application discloses a method for testing the hysteresis time of fasteners using a vacuum dual-chamber furnace, comprising the following steps.

[0014] S1: At room temperature, load the fasteners into the heating chamber of the vacuum double-chamber furnace according to the maximum loading capacity. Insert the test coupler from the rear door of the heating chamber of the vacuum double-chamber furnace and place the test coupler in the center of the fasteners. Then close the heating chamber. The vacuum double-chamber furnace has a built-in control coupler to monitor the set heating temperature. The test coupler is used to monitor the actual heating temperature reached by the fasteners.

[0015] S2: After evacuating the heating chamber, heat it, setting the preheating temperature K1. Heat the heating chamber of the vacuum dual-chamber furnace to the solution temperature K2; observe the control couple temperature curve and the test couple temperature curve, and refer to... Figure 1 or Figure 2 The control temperature curve is on top, and the test temperature curve is on the bottom. The holding time T is the time from the beginning of the test temperature curve slowing down to the preheating temperature K1 (holding time = T2 - T1). When heating to the solution temperature K2, control the time T3 for the dipole temperature curve to reach the set solution temperature K2, and test the time T4 for the dipole temperature curve to reach the actual solution temperature K2. The lag time = T4 - T3. Determine the time value corresponding to the solution temperature K2 according to the relevant standards for the start time of heat preservation of different materials. For example, according to AMS2759, the time T4 should be taken as the value corresponding to the lower limit of the actual solution temperature K2. The starting point for achieving the lag time is raised from room temperature to the preheating temperature K1, such as... Figure 3 As shown.

[0016] S3: The fasteners wait to be put into the furnace in the cooling chamber of the vacuum double chamber furnace; after the fasteners are cooled to the preheating temperature K1 in the heating chamber, they are put into the heating chamber of the vacuum double chamber furnace and held at the preheating temperature K1 for a holding time T, and then heated from the preheating temperature K1 to the solution temperature.

[0017] The technical solution adopted in this application achieves the cooling of the heating chamber of the vacuum double-chamber furnace from the solution temperature to the preheating temperature K1, and the heating of fasteners from the preheating temperature K1 to the solution temperature. This avoids the situation where the heating chamber of the vacuum double-chamber furnace is heated from room temperature to the solution temperature and then cooled back to room temperature, solving the problem of long cooling time after heating fasteners in existing vacuum double-chamber furnaces, and achieving a shorter waiting time for the next batch. In this application, the process of cooling the heating chamber of the vacuum double-chamber furnace to below the preheating temperature K1 and then reheating it to the solution temperature avoids energy waste and long equipment idle time compared to the process of cooling the heating chamber of the vacuum double-chamber furnace to room temperature and then reheating it to the solution temperature.

[0018] Example: The machining specification is MJ8×1, and the material is InconelX750. It is a twelve-point precision bolt.

[0019] The steps for using the above-mentioned method for testing the hysteresis time of a vacuum dual-chamber furnace for fasteners are as follows.

[0020] S1: Prepare test materials, 60Kg of InconelX750 alloy bolts; Each layer of fixture is fitted with 20kg of alloy bolts. The alloy bolts are distributed across the three layers of fixture and are evenly laid out within the fixture. The alloy bolts are fed into the heating chamber of the vacuum double-chamber furnace at room temperature along with the tooling. The rear door of the heating chamber is opened, and the test coupler is fixed in the middle of the second layer of tooling. The rear door of the heating chamber is then closed.

[0021] S2: After evacuating the heating chamber to <1.33 Pa, heat to 850℃, preheat and hold for 30 min, then increase the temperature at (8-12)℃ / min to the solution temperature of 1160℃; calculate the hysteresis time, where hysteresis time = time for the test couple to reach the lower limit of the set temperature T4 - time for the control couple to reach the set temperature T3. The obtained hysteresis time data can be found in [reference needed]. Figure 2 ; Figure 2 In the diagram, the green line at the top represents the temperature curve of the thermocouple, and the orange line at the bottom represents the temperature curve of the test thermocouple.

[0022] S3: After the first batch of Inconel X750 alloy bolts is held at a certain temperature in the heating chamber of the vacuum double-chamber furnace, it is transferred to the cooling chamber for oil cooling before being removed from the furnace. While the heating chamber of the vacuum double-chamber furnace is cooling down, the second batch of Inconel X750 alloy bolts can enter the cooling chamber of the vacuum double-chamber furnace to wait. When the temperature in the heating chamber of the vacuum double-chamber furnace drops to 850°C, the second batch of Inconel X750 alloy bolts is placed into the heating chamber of the vacuum double-chamber furnace for preheating and holding for 30 minutes. Then, the second batch of Inconel X750 alloy bolts is heated from the preheating temperature to a solution temperature of 1160°C. Subsequent batches of Inconel X750 alloy bolts are all placed from the preheating temperature into the heating chamber of the vacuum double-chamber furnace for heating to a solution temperature of 1160°C, and then removed to the cooling chamber of the vacuum double-chamber furnace for cooling to room temperature, thereby improving the utilization efficiency of the heating chamber of the vacuum double-chamber furnace.

Claims

1. A method for testing the hysteresis time of fasteners using a vacuum dual-chamber furnace, characterized in that, include: The test process is implemented to calculate the lag time of fasteners starting from the preheating temperature K1.

2. The method for testing the hysteresis time of a vacuum dual-chamber furnace for fasteners as described in claim 1, characterized in that, The testing process includes step S1: Loading the furnace with the maximum loading capacity, placing the fasteners into the heating chamber of the vacuum double-chamber furnace at room temperature, inserting the test coupler through the rear door of the heating chamber of the vacuum double-chamber furnace, placing the test coupler in the center of the fasteners, and closing the heating chamber; the vacuum double-chamber furnace has a built-in control coupler to monitor the set heating temperature, and the test coupler is used to monitor the actual heating temperature reached by the fasteners.

3. The method for testing the hysteresis time of fasteners using a vacuum dual-chamber furnace as described in claim 2, characterized in that, The testing process also includes step S2: after evacuating the heating chamber, heating is performed, and the heating chamber of the vacuum double-chamber furnace is heated to the solid solution temperature K2; observe the control couple temperature curve and the test couple temperature curve, set the preheating temperature K1, with the control couple temperature curve on top and the test couple temperature curve on the bottom, and the holding time T is the time from the beginning of the test couple temperature curve slowing down to the preheating temperature K1.

4. The method for testing the hysteresis time of fasteners using a vacuum dual-chamber furnace as described in claim 3, characterized in that: Step S2 of the test process also includes: observing the time T3 when the dipole temperature curve reaches the set solution temperature K2 when heated to the solution temperature K2, and the time T4 when the dipole temperature curve reaches the actual solution temperature K2. The lag time = T4-T3. The time value corresponding to the solution temperature K2 is determined according to the regulations for the start time of heat preservation of different materials. The time T4 is taken as the value corresponding to the lower limit of the actual solution temperature K2. The starting point of the lag time is increased from room temperature to preheating temperature K1.

5. The method for testing the hysteresis time of fasteners using a vacuum dual-chamber furnace as described in claim 4, characterized in that, The testing process also includes step S3: after the fasteners are heated in the heating chamber of the vacuum double-chamber furnace, they are transferred to the cold chamber to cool and then taken out. The next batch of fasteners enters the cold chamber to wait. When the fasteners that have been preheated to the preheating temperature K1 in the heating chamber of the vacuum double-chamber furnace are placed in the heating chamber of the vacuum double-chamber furnace, they are kept at the preheating temperature K1 for a holding time T, and then heated from the preheating temperature K1 to the solution temperature.

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