GB/T 43316.6-2023Plastics - Determination of resistance to environmental stress cracking (ESC) - Part 6: Slow strain rate method (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents" Drafting:

This document is Part 6 of GB/T 43316 "Determination of Environmental Stress Crack Resistance (ESC) of Plastics": GB/T 43316 has been released the following sections are included:

---Part 1: General principles;

---Part 2: Constant tensile load method;

---Part 3: Bending method;

---Part 4: Ball pressure or acupressure method;

---Part 5: Constant tensile deformation method;

---Part 6: Slow strain rate method:

This document is modified to adopt ISO 22088-6:2006 "Determination of environmental stress cracking (ESC) resistance of plastics - Part 6: Slow strain rates Law":

The technical differences between this document and ISO 22088-6:2006 and their reasons are as follows:

---Replaced ISO 22088-1 with normatively cited GB/T 43316.1 to adapt to my country's technical conditions and increase operability (See Chapter 3);

---Added the definition of ESC index (see 3.12) to provide for the meaning of the result (see 9.5);

---Replaced ISO 527-2 (see 7.1) with normatively cited GB/T 1040.2 to adapt to my country's technical conditions and increase operability Doing things:

The following editorial changes have been made to this document:

---The description of other parts in the scope of ISO 22088-6:2006 is adjusted to the introduction of this document;

---Adjust the description of this method as a grade test in the scope of ISO 22088-6:2006 to the introduction of this document;

---Change the calculation method of the ESC index in the result representation to a descriptive statement (see 9.5):

Please note that some content in this document may involve patents: The publisher of this document assumes no responsibility for identifying patents:

Introduction

The stress that exists externally or internally, or both, when plastics are subjected to stresses or strains below their yield point in air:

The combined action of plastics can cause cracking: This type of cracking is often accelerated by the chemical environment in which the plastic is located: This phenomenon is called environmental stress:

Cracking (ESC): ESC damage can occur in many materials, including plastics, which can significantly reduce the ability of the material to survive long-term use:

force or strain:

The ESC process is as follows:

1) After applying stress, microscopic holes are formed in the sample due to stress concentration;

2) The action of the chemical environment causes the rupture of intermolecular bonds, causing the formation and expansion of larger pores, thereby forming interconnected pores:

Silver streaks composed of holes and microfiber structures;

3) Under the combined action of stress and chemical environment, the microfiber structure breaks and silver streaks grow;

4) Cracks appear at the tip of the craze and continue to develop, eventually leading to brittle failure:

Cracks may continue to develop along the thickness of the material until the material breaks into two or more fragments; cracks may also develop when low stress is reached:

forces, different materials, and/or different morphological regions:

The ESC test is relatively complex and is affected by the following parameters:

---Sample size;

---Sample state (orientation, microstructure, internal stress);

---Sample preparation method;

---Thermal history of the specimen;

---Stress and strain;

---Test temperature;

---Test duration;

---Chemical environment;

---Methods for applying stress and strain;

---Failure criterion:

By using one parameter as a variable and keeping other parameters unchanged, the impact of variable parameters on ESC can be evaluated: The main purpose of the ESC test the purpose is to determine the relative effects of chemical media on the plastics (specimens and articles) to which they are exposed:

When the failure modes are consistent with those obtained in actual use, these test results can be used to evaluate molding conditions for molding:

impact on product quality:

Since the influencing factors of product ESC performance in actual applications are more complex, the sample ESC test results and actual product performance are established:

Direct correlation is very difficult:

Environmental stress cracking testing is used as a quality control tool and in research and development to evaluate stress cracking resistance:

The test method is chosen based on the types of stresses or strains the material will be subjected to in service: When using constant strain testing methods such as the bending bar method or when using the needle intrusion method, be aware that the stress applied to the material will decay over time as the stress relaxes:

Select test conditions based on material variety and usage conditions: Compare the ESC properties of materials under the same test conditions:

GB/T 43316 "Determination of Environmental Stress Crack Resistance (ESC) of Plastics" aims to specify the environmental stress cracking resistance of thermoplastic plastics:

The general principles and description of its determination methods are intended to be composed of six parts:

---Part 1: General principles: The purpose is to establish general principles for determining the resistance of plastics to environmental stress cracking:

---Part 2: Constant tensile load method: The purpose is to establish the resistance of thermoplastics to a constant tensile load in a test medium:

An operational, traceable, and verifiable determination procedure for environmental stress cracking:

---Part 3: Bending method: The purpose is to establish thermoplastics capable of withstanding fixed bending strains in the presence of test agents:

An operational, traceable, and verifiable determination procedure for environmental stress cracking resistance:

---Part 4: Ball pressure or acupressure: The purpose is to establish a thermoplastic ring that can withstand constant strain when a ball or needle is pressed into it:

Operable, traceable, and verifiable measurement procedures for environmental stress cracking:

---Part 5: Constant tensile deformation method: The purpose is to establish a test medium for thermoplastics when subjected to constant tensile deformation:

Operable, traceable, and verifiable measurement procedures for environmental stress cracking resistance:

---Part 6: Slow strain rate method: The purpose is to establish for thermoplastics slowly increasing tension at a constant rate in the test medium:

An operable, traceable and verifiable measurement procedure for environmental stress cracking resistance under tensile specimen strain conditions:

Part 6 and other parts support each other and together form a standard system for determining the environmental stress cracking resistance of plastics:

The above tests for environmental stress cracking (ESC) resistance are essentially rating tests and are not intended to provide information for design or performance prediction:

data:

Determination of environmental stress cracking (ESC) resistance of plastics Part 6: Slow strain rate method

1 Scope

This document describes the resistance of thermoplastics to environmental stress cracking when the strain of a tensile specimen is slowly increased at a constant rate in a chemical medium:

(ESC) test method:

This document applies to specimens prepared by molding and/or machining for the determination of environmental stress cracking resistance of plastics exposed to different environments:

Environmental stress cracking resistance of different plastics when exposed to specific environmental conditions:

2 Normative reference documents

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

GB/T 1040.2 Determination of tensile properties of plastics Part 2: Test conditions for molded and extruded plastics (GB/T 1040.2-2022,ISO 527-2:2012,MOD) GB/T 43316.1 Determination of environmental stress cracking (ESC) resistance of plastics Part 1: General principles (GB/T 43316.1-2023, ISO 22088-1:2006,MOD)

3 Terms and definitions

The terms and definitions defined in GB/T 43316.1 and the following apply to this document:

CHD

The distance traveled by the beam from the start of the test:

Crosshead speed CHS Crosshead displacement (CHD) divided by test time:

The length of the narrow parallel section in the middle of the specimen (see Figure 1):

areaofparallel-sidedsection A1 the cross-sectional area of the narrow parallel portion of the specimen (see Figure 1):