What is a low temperature test? Low temperature test conditions and methods

Date：2022-02-21 13:39:29Views：2271

Low temperature test is mainly used to evaluate the impact of low temperature conditions on the safety, integrity and performance of equipment during storage, work and disassembly. To determine the sequence of low temperature test, two principles should be followed: maximize the service life of equipment and the applied environment should be able to display the superposition effect to the greatest extent. The purpose is to test whether the test piece can be stored, manipulated and controlled in a long-term low-temperature environment, and to determine the adaptability and durability of military and civil equipment under low-temperature conditions. Physical and chemical properties of materials at low temperature. The standard has specification requirements for pre-test treatment, initial test, sample installation, intermediate test, post-test treatment, heating rate, load condition of temperature cabinet, volume ratio of measured object to temperature cabinet, etc.

Failure mode of test piece at low temperature:The parts and materials used in the product may crack, embrittlement, jamming of movable part, characteristic change and other phenomena at low temperature.

Test conditions for low temperature test:

Low temperature point, low temperature test time and temperature change rate.

Time of low temperature test:

The low-temperature working test is generally at least 2 hours, and the storage is 12 hours or 24 hours. The test time is clearly specified according to the actual application environment of the product and relevant standards. This test time can be selected according to the actual situation.

Generally, the temperature point of low-temperature operation test is relatively loose than that of low-temperature storage test. The operation or start-up test is to be powered on for performance test, which is relatively harsh.

Low temperature environmental test belongs to the type of environmental adaptability test of ultimate stress. Before the test, it is necessary to clearly understand the low temperature test requirements of the user and relevant standards for products.

Effect of low temperature

1. Make the material hard and brittle;

2. The lubricant viscosity increases, the flow capacity decreases and the lubrication effect decreases;

3. The performance of electronic components changes;

4. Water condensation and freezing;

5. Seal failure;

6. Material shrinkage causes changes in mechanical structure.

Scope of application

Low temperature test is mainly used for scientific research, preservation of medical supplies, low temperature experiment and storage of biological products, ocean products, electronic components, chemical materials and other special materials.

Low temperature test standard

Environmental testing of electric and electronic products Part 2: Test methods test a: low temperature GB / T 2423.1-2008, IEC 60068-2-1:2007

Packaging - Basic tests for transport packages - Part 2: temperature and humidity conditioning treatment (GB / T 4857.2-2005, ISO 2233:2000)

Basic technical conditions for automotive electrical equipment QC / T 413-2002

General specification for electronic measuring instruments GB / T 6587-2012

General specification for computers Part 1: desktop microcomputers GB / t9813 1-2016

General specification for computer part 2: portable microcomputer GB / T 9813.2-2016

General specification for computer part 3: server GB / T 9813.3-2017

General specification for computers Part 4: microcomputer for industrial applications GB / t9813 4-2017

Military equipment laboratory environmental test methods Part 4: low temperature test GJB150 4A-2009