GB/T 7991.3-2021Test method of viterous and porcelain enamels—Part 3: Determination of resistance to thermal shock (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules of Standardization Documents" drafted.

This document is part 1 of GB/T 7991 "Test methods for glass-lined layers". GB/T 7991 has released the following parts.

--- Part 1: Determination of corrosion resistance to alkaline solutions;

--- Part 3: Determination of resistance to sudden changes in temperature;

--- Part 4: Determination of mechanical shock resistance;

--- Part 5: Thickness measurement by electromagnetic method;

--- Part 6: High voltage test;

--- Part 7: Determination of the mean coefficient of linear thermal expansion;

--- Part 9: Determination of tensile strength;

--- Part 10: Determination of lead and cadmium dissolution.

This document replaces GB/T 7987-2013 "Test Method for Rapid Deformation Resistance of Glass-Lined Layers to Temperature Difference", compared with GB/T 7987-2013, except In addition to structural adjustments and editorial changes, the main technical changes are as follows:

a) Changed the "test principle" (see Chapter 4, Chapter 3 of the 2013 edition);

b) Changed "Apparatus and Instruments" (see Chapter 5, Chapter 4 of the 2013 edition);

c) Changed the shape and size of the sample (see Chapter 6, Chapter 5 of the 2013 edition);

d) Added the requirement that the glass-lined layer of the sample should pass the 10kV high voltage test (see 6.2);

e) Changed the test procedure (see Chapter 7, Chapter 6 of the 2013 edition);

f) The requirements for "making ice-water mixtures" have been added to Chapter 7 (see 7.3).

Introduction

GB/T 7991 aims to accurately measure the performance data of the glass-lined layer, and is intended to consist of 10 parts.

--- Part 1: Determination of corrosion resistance to alkaline solutions;

--- Part 2: Determination of resistance to boiling acid and its vapor corrosion properties;

--- Part 3: Determination of resistance to sudden changes in temperature;

--- Part 4: Determination of mechanical shock resistance;

--- Part 5: Thickness measurement by electromagnetic method;

--- Part 6: High voltage test;

--- Part 7: Determination of the mean coefficient of linear thermal expansion;

--- Part 8: Determination of scratch resistance;

--- Part 9: Determination of tensile strength;

--- Part 10: Determination of lead and cadmium dissolution.

These ten performance parameters are very important to glass-lined equipment, and are directly related to the quality and service life of glass-lined equipment.

The glass-lined layer's resistance to rapid temperature difference is a very important performance parameter of glass-lined equipment. During the use of glass-lined equipment, the It is unavoidable to withstand the impact of high and low temperature. If the glass-lined layer has poor resistance to rapid temperature difference, the rapid temperature change will cause the glass-lined layer to be damaged and exploded. Equipment is scrapped.

After the improvement of the experimental device in this document, the experimental error has been greatly reduced, and the difference of the experimental results in different regions, seasons and environments has been reduced. different. Moreover, this method is also closer to the actual working conditions of glass-lined equipment, and can more accurately measure the resistance of glass-lined layers to sudden changes in temperature. according to. To optimize the formulation of glass-lined glaze, evaluate the rationality and advancement of the firing process of glass-lined equipment, and improve the quality and quality of glass-lined equipment. Service life is very important.

1 Scope

This document describes the test principle of the glass-lined layer's resistance to abrupt changes in temperature, and specifies the test equipment and instruments, test specimens, test procedures, and results. Results judgment and test report.

This document is applicable to the determination of the resistance to sudden changes of temperature difference of glass-lined flat plate specimens.

2 Normative references

The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, dated citations documents, only the version corresponding to that date applies to this document; for undated references, the latest edition (including all amendments) applies to this document.

GB/T 7991.6 Test method for glass-lined layer - Part 6: High voltage test

HG/T 3105 Preparation of Steel Plate Glass-Lined Specimen

3 Terms and Definitions

There are no terms and definitions that need to be defined in this document.

4 Test principle

After heating the sample to the thermal shock test temperature, spray cold water on the surface of the glass-lined layer of the sample, dry the glass-lined layer of the sample, and observe the lining of the sample. Whether the glass layer is damaged such as cracking, cracking, peeling, etc. If no damage to the glass lining is found after the first thermal shock test, the The high test temperature is 10 °C, and the thermal shock test is repeated until the glass-lined layer of the sample is damaged. The previous test temperature at which failure occurred is the same as the The difference in water temperature is the temperature resistance value of the glass-lined sample.

5 Apparatus and instruments