MIL-STD-810H High Temperature (Method 501.7) Test Machine.

MIL-STD-810H (Method 501.7) High Temperature

MIL-STD-810G (Method 501.5)Test Machine

The MIL-STD-810H (Method 501.7) High Temperature Test Machine is designed to assess the reliability of a device under high-temperature conditions. This test simulates the effects of temperature increases on electronic components and evaluates the device’s durability in such environments.

1. Scope

1.1 Purpose:

This test is used to evaluate the effects of high temperature conditions on material safety, integrity, and performance.

1.2 Application:

This method is suitable for evaluating materials that are likely to be exposed to temperatures higher than standard ambient temperatures.

1.3 Limitations:

This test method is not suitable for evaluating aging effects due to long-term (years-long) exposure to high temperatures. Additionally, it is generally not recommended for the following situations:

• For materials directly exposed to solar radiation (Method 505.7, Procedure I should be used).
• For the evaluation of photochemical (actinic) effects (Method 505.7, Procedure II should be used).
• For the evaluation of aerodynamic heating effects.

2. Test Tailoring Guidance

2.1 Selecting this method

Requirement documents should be reviewed to determine whether high-temperature exposure is expected in the material’s life cycle.

2.1.1 Effects of high-temperature environments

• Compression of parts due to differential expansion of materials with different thermal expansion coefficients.
• Decreased fluidity and loss of lubricants.
• Dimensional changes in materials.
• Deformation of seals, gaskets, and bearings.
• Electronic circuit stability being affected by temperature variations.
• Changes in resistance values.
• Degradation of adhesives and cracking of organic materials.
• Increased pressure in sealed containers.
• Expansion or accelerated combustion of explosive and propellant materials.

2.1.2 Sequencing with other test methods

This test can be applied together with Method 505.7 (Solar Radiation Test) to provide a more realistic assessment of real-world conditions.

2.2 Test procedure selection

This method includes three different test procedures:

1. Procedure I – Storage: Evaluates the effects of long-term storage at high temperatures on the material.
2. Procedure II – Operation: Evaluates the effects of high ambient temperatures on materials while in operation.
3. Procedure III – Tactical Standby – Operation: Evaluates the operability of materials stored in enclosed compartments exposed to solar radiation.

2.3 Determining test levels and conditions

• Climatic conditions: The material should be tested under real field conditions.
• Exposure duration: Continuous or cyclic temperature exposure should be determined.
• Material configuration: The real-world positioning of the material during storage and operation should be evaluated.

3. Information Required

3.1 Pre-test preparations

• Need for humidity control (if applicable).
• Temperature measurement points and sensor locations.
• Maximum storage temperature and ambient temperature.

3.2 Data to be collected during the test

• Temperature-time records of the test chamber.
• Temperature-time data of the tested material.

3.3 Post-test data

• Recorded temperature variations during the test.
• Visual inspection results.
• Operational status and functionality of the tested material.

4. Test Process

4.1 Test Facility and Equipment

• A temperature chamber or cabinet should be designed to maintain the surrounding air temperature of the material at the specified level.
• Airflow should be adjusted to match real environmental conditions for the tested material.

4.2 Test Controls

• The rate of temperature change should not exceed 3°C per minute.
• During testing, temperature deviation should not exceed 2°C.

4.3 Test Interruptions

• Test chamber failure: If the test is interrupted, the material should be returned to the last successfully completed temperature level before resuming the test.
• Material failure: If the test item fails, the test should be restarted from the beginning with a new specimen.

4.4 Test Implementation Procedures

• Procedure I – Storage: Evaluates the effects of storage at high temperatures on the material.
• Procedure II – Operation: Tests the material’s ability to function under high temperature conditions.
• Procedure III – Tactical Standby – Operation: Assesses the transition of materials exposed to solar radiation into operational status.

5. Analysis of Results

Test results are analyzed based on the following:

• Physical damage: Cracks, deformations, loss of sealing.
• Functional degradation: Failures in electrical or mechanical components.
• Chemical effects: Changes in material composition.
• Special requirements: Additional analyses should be conducted for materials that must operate under specific temperature conditions.

6. References and Related Documents

• MIL-STD-810H
• NATO STANAG 4370, AECTP 230 (Climatic Conditions)
• MIL-HDBK-310 (Global Climatic Data)

Key Features

Feature Value / Description Temperature Range From +55°C to +85°C Test Duration Between 24 hours and 1000 hours Temperature Change Rate 10°C per hour Test Method Utilizes a hot air chamber Test Result Evaluates the reliability and longevity of devices at high temperatures

Application Areas

• Electronics: Devices with or without cooling mechanisms operating under high temperatures.
• Military Equipment: Vehicles and devices operating in high-temperature environments.

Advantages

• Assesses the performance of electronic components under extreme temperatures.
• Tests the device’s resistance to long-term temperature changes.

For more information about MIL-STD-810H (Method 501.7) and to place an order, please contact us!

Standard reference

MIL-STD-810H Method 501.7 defines High-Temperature procedures: Procedure I — Storage and Procedure II — Operation. The temperature levels and diurnal cycles are taken from the climatic category of the deployment region; the item may be tested at constant or cycling high temperature.