Keywords: Quench, sampling, calibration, testing temperature, testing steps, steps, quenching oil, thermocouple, temperature, frequency,

　　The test process includes sampling, calibration, adjusting the test temperature, testing and other steps, and the technical requirements of each step are shown in the table.
　　table technical requirements for each step of the test process
　　name technical requirements
sampling
　　2L quenching oil sample is required, and the oil sample shall be collected carefully to ensure its representativeness. To avoid contamination, the container holding the oil sample should be clean and dry.
Calibration
　　1. Probe Thermocouple Calibration
　　① Calibrate the probe thermocouple by binding a previously calibrated thermocouple to the outer surface of the probe and heating the probe to the test temperature.
　　When the probe temperature reaches equilibrium, use a potentiometer to compare the output of the two thermocouples. In the measurement temperature (850 & plusmn; Within the range of 5)℃, if the output error of the probe thermocouple exceeds & plusmn of the given value; 2%, the probe will be scrapped.
　　② Frequency of recalibration. For new probes, calibrate the probe as required before use, for probes in use, before the start of no more than 25 series of experiments, and for probes in normal use, after every 25 experiments.
　　③ Compensation of error. Before the start of the experiment, the error determined at the time of calibration was recorded. When determining the probe temperature value and recording the result data, add or subtract as appropriate.
　　2. Calibration of Recorder and Differentiator
　　① Temperature axis. Before the start of each experiment, check the setting of the zero point, and before the start of consecutive experiments, check the scale of the figure with a potentiometer. For example, an input of 34mV gives a movement of 170mm.
　　② Speed axis. The differentiator shall have the ability to be calibrated either by a complete calibration device or by external experimental equipment. The calibration of the differentiator shall be checked before the start of each successive experiment. 5mV/s, 10mV/s, 20mV/s input rate should be able to give the selected 250mm graphic scale. Before the start of each experiment, check the setting of the zero point.
　　③ Timeline. Before the start of each successive experiment, the speed of the recording paper was checked using a stopwatch.
Adjust the test temperature
　　1. Probe temperature. The standard probe temperature should be 850 ^. In the air, the probe is heated to (850 & plusmn;5) and the probe should be kept at this temperature for 5 minutes before the test starts.
　　During each experiment, make appropriate corrections based on the temperature axis of the F & mdash; recorder, and consider the errors displayed by the cold end compensation and the probe thermocouple calibration to determine the probe temperature value. Before the test, the cold junction and probe thermocouple calibration values should be recorded on the table.
　　2. The temperature of the sample. Quench oil samples should be tested within the temperature range specified for product use. The temperature of the quenching oil can be selected to meet individual requirements. For ease of comparison, unless otherwise emphasized, the recommend test is carried out at an oil temperature of 40T. At the beginning of the test, the temperature of the quenching oil shall be within & plusmn;2 ℃ of the set test temperature.
　　In order to reduce the thermal gradient, the quenching oil sample should be properly stirred during heating, and the temperature of the oil sample should be checked before starting the experiment. The experiment should be carried out in a still oil sample.
test
　　1. Put the quenching oil sample to be tested into the container. If necessary, adjust the oil sample to the required experimental temperature. During heating, the quenching oil sample should be stirred to reduce the thermal gradient.
　　2. Put the initialized, cleaned and calibrated probe into the heating furnace and heat it to the set temperature.
　　Disconnect the heating furnace power supply before quenching (to avoid possible interference with the control system) and put down the stylus. Move the probe from the furnace into the quenched oil sample to ensure that the event trigger records the moment the probe is in contact with the oil sample.
　　When the probe temperature drops to 200 ℃, or the low temperature value required by the specified experiment, turn off the recorder and differentiator, remove the probe from the oil, and complete the specified cleaning process.

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