ASTM D746 Brittleness Temperature Test of Plastics and Elastomers by Impact / Low Temperature Brittleness Tester

ASTM D746 Brittleness Temperature Test of Plastics and Elastomers by Impact / Low Temperature Brittleness Tester

1. Overview

The maximum temperature at which the sample is damaged by impact under the specified conditions, that is, the brittleness temperature, can be used to comparatively evaluate the performance of plastics and other elastic materials under low temperature conditions. The brittle temperature and low temperature properties of vulcanized rubbers of different rubber materials or different formulations can be determined. Therefore, it is indispensable in the quality inspection of scientific research materials and their products, and the control of production processes. The instrument is designed according to GB1682 national standard, and the technical indicators meet the requirements of HG 2-162-1965 plastic low temperature impact compression test method and GB5470-2008 plastic impact embrittlement temperature test method.

2. Use and specific design parameters

Uses: It can measure the brittleness temperature and low temperature performance of vulcanized rubber of different rubber and plastic materials or different formulations, so it is indispensable in the quality inspection of scientific research materials and their products, and control in production process.

3. Main design parameters

(1) Test temperature: -70°C - normal temperature

(2) Impact speed: 2m/s ± 0.2m/s

(3) After the constant temperature, the temperature fluctuation within 3min of the test: < ±0.5°C

(4) Impact blade radius: 1.6 ± 0.1mm

(5) The radius of the jaw under the clamp arc: 4.0 ± 0.1mm

(6) The gap between the outer side of the impact blade and the clamp: 2.0 ± 0.1mm

(7) The distance between the impact point of the impact blade and the fixture: 3.6±0.1mm

(8) Test speed within 5mm after impact, and after impact: 200cm/s

(9) External dimensions: 900 × 505 × 800mm (length × height × width)

(10) Studio dimensions: 220 × 170 × 70mm (length × height × width)

(11) Cooling medium: ethanol or other antifreeze

(12) Working power 220V~240V, 50Hz, 1.5kW

4. Structure principle

(1) The equipment consists of the main body of the refrigeration compressor, heating device, electronic control box, cooling tank, cooling medium circulation system, automatic alarm device, etc.

(2) Lifting clamp

The distance from the impact portion of the sample to the lower end of the holder is 11 ± 0.5 mm.

(3) Impactor

Impactor head shape and size. The working stroke of the impactor is 40±1mm.

5. Method of use

(1) Inject cold medium (usually industrial ethanol) into the cold well, and the injection amount should ensure that the distance from the lower end of the holder to the liquid surface is 75±10mm.

(2) Turn on the power, and the temperature controller and timer display lights.

(3) The sample is clamped vertically on the holder. The clip should not be too tight or too loose to prevent the sample from deforming or falling off.

(4) Press the gripper to start freezing the sample and start the timing control switch (or press the stopwatch) to time. The freezing time of the sample was specified to be 3.0 ± 0.5 min. During the freezing of the sample, the temperature of the freezing medium should not exceed ±1 °C.

(5) Lift the lifting clamp so that the impactor impacts the specimen within half a second.

(6) After the sample is impacted (only one impact per sample), if there is damage, the temperature of the freezing medium should be increased, otherwise the temperature will be lowered and the test will continue.

Through trial and error, the lowest temperature at which at least two samples are not destroyed and the highest temperature at which at least one sample is destroyed are determined. If the difference between the two results is not more than 1℃, the test is finished.

6. Test criteria

Specifications

The sample has a length of 20.0 ± 0.25 mm, a width of 2.5 ± 0.1 mm, and a thickness of 1.6 ± 0.1 mm.

Requirements

The surface of the sample should be smooth and free of foreign matter and damage. The finished product should be ground to the appropriate size.

7. Installation guide

(1) During the handling and installation of this equipment, it is strictly forbidden to vibrate vigorously, and the inclination shall not be greater than 450;

(2) The equipment should be placed 0.2 meters away from the wall for a long time, and it should be well ventilated to avoid direct sunlight exposure.

(3) Carry out a comprehensive inspection of the equipment to ensure that the parts are intact.

(4) Open the cooling tank cover, take out the sample basket and temperature sensor, and insert the temperature sensor plug into the socket at the back of the box. Please be sure to insert it firmly. Otherwise, the temperature display is abnormal and the “-1” display appears. At this time, the heating tube will heat up. The cooling medium in the heating tank, if there is no cooling in the tank, the heating tube will burn out in an instant.

(5) Connect the 220V, 50Hz power supply, and ensure that the grid voltage is between 220V~240V. It is recommended to configure a 5kW AC voltage regulator.

(6) Before the first use of the new machine, please open the side net cover. When pressing the “refrigeration” switch, observe the working condition of the compressor. The correct work should be: the compressor is pressed when the “cooling” switch is pressed. The compressor starts immediately (touch the compressor by hand and feel the vibration). After about 5 minutes, the lower compressor starts to start.

8. Operation steps

(1) Add an appropriate amount of cooling medium to the cooling bath.

(2) After confirming that the power supply is under the specified voltage and grounding safety, and the parts of the equipment are under normal conditions, the power switch is turned off.

(3) Press the temperature setting button (set) for 0.5 seconds and then release the temperature setting. Press the key of the plus or minus key to set the temperature. After setting the required temperature, press the set button for 0.5 seconds to return to normal operation and memorize the parameter values. At this point the device starts working;

(4) Press the agitator switch to check if the coolant in the cooling bath is flowing.

(5) Finally press the cooling switch.

(6) When the medium in the cooling tank approaches the set temperature, the constant temperature heating device works and the indicator light flashes;

When the set temperature is reached, the automatic alarm device sounds, the constant temperature timer starts to record, and the constant temperature time is displayed. When the operator hears the news, the alarm switch can be turned off. When the constant temperature timer displays the required constant temperature time, The sample was removed for testing.

(7) Press the move key to clear the time value of the temperature set value display window.

9. Matters Needing Attention

This equipment has been adjusted before leaving the factory and cannot be changed arbitrarily.

10. Daily maintenance and precautions

(1) Maintain the condition of the equipment, strictly prohibit vibration and collision, and do not disassemble at will. The inclination should not exceed 45° when carrying.

(2) Equipment should not be placed near high temperatures or exposed to sunlight.

(3) The electric control box should be protected from moisture, and it is strictly forbidden to enter any liquid.

(4) Before starting the machine, it must be ensured that the ground wire is connected to ensure safety; the power plug must be inserted firmly to prevent the compressor from being destroyed due to looseness and burning.

(5) In case of power failure or failure, the restart interval must be greater than 30 minutes; when the room temperature exceeds 25℃, the restart interval must be greater than 60 minutes.

(6) If the compressor does not start up, and the intermittent operation will stop suddenly after a period of time, please shut down immediately, first check if the power supply voltage is 220V~240V. If it does not meet, please check the grid voltage or configure the AC voltage regulator to make it reach the normal working voltage value of the instrument.

(7) Secondly, attention should be paid to the ambient temperature. The cryostat is recommended to be used at an ambient temperature of 25℃. Because the ambient temperature is too high, the pressure in the compressor system is too high. If the grid capacity is insufficient or the voltage is low, start at this time. It is more difficult, and the interval between two power-ons is much longer.

(8) The sample placed in the cooling tank should be wiped clean. Do not bring foreign matter such as iron filings into the cooling tank to avoid blocking the circulation line.

(9) Before using again, check the amount of cooling medium in the tank. The appropriate amount of cooling medium should cover the evaporator copper tube (otherwise the evaporator is easy to frost, increase the water content of the cooling medium) and reach the upper end of the mixing cycle. Height (otherwise the circulation is not smooth) is appropriate, if the use temperature is low, please pay attention to the change of the volume of the cooling medium caused by the temperature, the cooling medium should be replenished in time.

(10) The cooling medium should be released after each use.

(11) The cooling medium should be replaced regularly to minimize the impurity content and water content. Otherwise, the circulation is not good and the cooling effect and temperature accuracy are affected.

(12) When pressing the "Power" switch, make sure that the cooling bath is filled with cooling medium and that the temperature sensor is not allowed to be removed from the cooling bath.

FAQ

Q: Are you trading company or manufacturer ?

A: We are a manufacturer.

Q: How long is your delivery time?

A: Generally it is 5-10 days if the goods are in stock. or it is 15-20 days if the goods are not in stock, it is according to quantity.

Q: Do you provide samples ? Is it free or extra ?

A: No, we don't provide the samples for testing.

Q: What is your terms of payment ?

A: Payment<=1000USD, 100% in advance. Payment>=1000USD, 50% T/T in advance ,balance before shipment.
If you have another question, please feel free to contact us.

Q: What is your terms of payment ?

A: The warranty for the equipment is 1 year. Definitely, all equipment are tested well and runs well by testing our customer's sample before shipment. Please contact us if the equipment doesn't work well after being shipped to your company. We will guide you how to fix it. The spare parts or components will be sent if necessary. The charges will be occurred if it is caused by customer's misoperation.