GB/T 7991.7-2019 in English

Introduction

GB/T 7991.7—2019 "Test methods for glass-lined layers Part 7: Determination of average linear thermal expansion coefficient" is an important national standard used to regulate the measurement method of the linear thermal expansion coefficient of glass-lined glaze at different temperatures. This standard replaces the previous GB/T 25144—2010, and has made many improvements and optimizations in technical requirements, experimental equipment and operating procedures.

Background of standard revision

With the widespread application of glass-lined materials in the fields of chemical industry and pharmaceuticals, the performance requirements for glass-lined layers are increasing. The original standard GB/T 25144—2010 can no longer meet modern testing needs in terms of experimental equipment accuracy and operating procedures. This revision introduces new test principles and higher technical requirements to ensure the accuracy and reliability of measurement results.

Main technical requirements

Experimental equipment and operating specifications

Test steps and data analysis

The test is divided into three stages: initial length determination, heating process control and data correction. The average linear thermal expansion coefficient is calculated by formula to ensure that the test accuracy is within ±3×10⁻⁷℃⁻¹.

Implementation suggestions

To ensure the effective implementation of the standard:

• The laboratory needs to be equipped with a dilatometer and heating furnace that meet the requirements.
• Operators should undergo professional training and be familiar with the experimental process and data processing methods.
• It is recommended to calibrate the equipment regularly and use standard samples for verification.