GB/T 20671.1-2020Classification system and test methods for nonmetallic gasket materials—Part 1: Standard classification system for nonmetallic gasket materials (English PDF)

Foreword

GB/T 20671, Classification system and test methods for nonmetallic gasket materials, is divided into 11 parts:

-- Part 1: Standard classification system for nonmetallic gasket materials;

-- Part 2: Standard test method for compressibility and recovery of gasket materials;

-- Part 3: Standard test method for fluid resistance of gasket materials;

-- Part 4: Standard test method for sealability of gasket materials;

-- Part 5: Standard test method for creep relaxation of gasket materials;

-- Part 6: Standard test method for adhesion of gasket materials to metal surfaces;

-- Part 7: Standard test methods for tension testing of nonmetallic gasket materials;

-- Part 8: Standard test method for flexibility of non-metallic gasket materials;

-- Part 9: Standard test method for binder durability of cork composition gasket materials;

-- Part 10: Standard practice for evaluating thermal conductivity of gasket materials;

-- Part 11: Standard practice for determining resistance of synthetic polymeric materials to fungi.

This Part is Part 1 of GB/T 20671.

This Part was drafted in accordance with the rules given in GB/T 1.1-2009.

This Part replaces GB/T 20671.1-2006, Classification system and test methods for nonmetallic gasket materials - Part 1: Standard classification system for nonmetallic gasket materials. Compared with GB/T 20671.1-2006, the main technical changes, except editorial changes, are as follows:

-- Change "Classification basis" to "Classification method" and "Code definition" (see Chapter 3, Chapter 4; Chapter 4 of version 2006);

-- Modify the method of some codes, and delete "ASTM F104" (see 3.3; 4.3 of version 2006);

1 Scope

This Part of GB/T 20671 specifies the classification method, code definition, thickness requirements and measurement methods, sampling and sample adjustment of nonmetallic gasket materials.

This Part applies to materials which are made of asbestos, cork, cellulose and other inorganic or organic materials combined with various adhesives or impregnant. It does not apply to rubber product materials, gasket coating materials or multilayer composite gasket materials; but the surface layer single-layer material of the multilayer composite gasket material is also suitable for this classification system.

2 Normative references

The following documents are indispensable for the application of this document.

For dated references, only the dated version applies to this document. For undated references, the latest edition (including all amendments) applies to this document.

GB/T 20671.2-2006, Classification system and test methods for nonmetallic gasket materials - Part 2: Standard test method for compressibility and recovery of gasket materials

GB/T 20671.3, Classification system and test methods for nonmetallic gasket materials - Part 3: Standard test method for fluid resistance of gasket materials

GB/T 20671.4, Classification system and test methods for nonmetallic gasket materials - Part 4: Standard test method for sealability of gasket materials

GB/T20671.5, Classification system and test methods for nonmetallic gasket materials - Part 5: Standard test method for creep relaxtion of gasket materials […]

3 Classification method

3.3 The sequence of the six-digit code that represents the basic characteristics is defined as:

a) reinforcement classification;

b) manufacturing method;

c) compressibility;

d) thickness increase rate after immersion in IRM 903 oil;

e) mass increase rate after immersion in IRM 903 oil;

f) mass increase rate after immersion in water.

Example: For the gasket material that is coded as GB/T 20671 (F725400), its basic characteristics are defined as follows (see Table 1):

The first code 7 represents non-asbestos fiber; the second code 2 represents the beating and copying process; the third code 5 represents that in accordance with the test of GB/T 20671.2-2006, the compressibility is 20% ~ 30%; the fourth code 4 represents that in accordance with the test of GB/T 20671.3, the thickness increase rate after immersion in IRM903 oil is 15% ~ 30%; the fifth digit code 0 represents the mass increase rate without considering the immersion in IRM903 oil; the sixth digit code 0 represents the mass increase rate that is obtained without considering the immersion in water.

3.4 According to the needs of the application conditions, specified supplementary characteristics can be added after the basic characteristics.

Example: For the gasket material that is coded as GB/T 20671 (F725400- B5E66M4), the definition of its basic characteristics has been given in the example of 3.3, and its supplementary characteristics are defined as follows (see Table 2): […]