GB/T 7690.6-2013Reinforcements -- Test method for yarns -- Part 6: Determination of twist balance index (English PDF)

Foreword

GB/T 7690 "Test method for yarns enhanced" is divided into six sections.

--- Part 1. Determination of linear density;

--- Part 2. Determination of twist;

--- Part 3. Glass fiber breaking force and elongation measurement;

--- Part 4. Determination of stiffness;

--- Part 5. Determination of glass fiber diameter of the fiber;

--- Part 6. Determination of twist balance index.

This section GB/T Section 67690 of.

This section drafted in accordance with GB/T 1.1-2009 given rules.

This Part replaces GB/T 7690.6-2001 "enhanced method for yarns - Part 6. Determination of twist balance index", and GB/T 7690.6-2001 compared to, in addition to editorial changes outside the main technical changes are as follows.

--- In a broader range of applications, in addition to the original standard glass fiber coated carbon fiber and aramid fiber yarn, but also includes other Reinforcing fibers (see Chapter 1);

--- Remove the "Reference Standards" GB/T 18374, an increase of ISO 291 (see Chapter 2, Section 2 of the 2001 edition);

--- Remove the "Definitions" chapter (see Chapter 3 of the 2001 edition);

--- Added "sample" and "test the humidity and the environment" chapters (see Chapter 4, Chapter 5).

This section uses the translation method identical with ISO 3343:2010 "Enhanced yarn twist balance index determination", made the following editorial modify.

--- Modify the standard name.

The correspondence between the consistency of the international normative documents referenced in our country with the following documents.

--- GB/T 2918-1998 plastic sample conditioning and testing of the standard environment (ISO 291:1997, IDT).

This part of the National Standardization Technical Committee fiberglass (SAC/TC245) centralized.

This section is responsible for drafting. Nanjing Fiberglass Research and Design Institute Limited, the national glass fiber product quality supervision and inspection center.

1 Scope

GB/T 7690 provisions of this part of the ply yarns and cables made of glass fiber, carbon fiber, aramid fiber or other reinforcing fibers Determination of twist balance index.

2 Normative references

The following documents for the application of this document is essential. For dated references, only the dated version suitable for use herein Member. For undated references, the latest edition (including any amendments) applies to this document.

ISO 291 environmental standard plastic sample conditioning and testing (Plastics-Standardatmospherefor conditioningandtesting) Principle 3 the yarn is put into a predetermined length and width of the opening of the coil, and count the number of twist yarns own making.

4 Sample

A unit of product 1) or laboratory sample 2) continuous take five samples were measured.

5 Conditioning and testing environment

Without the humidity. In case of disputes, the temperature should be specified in ISO 291 is (23 ± 2) °C, relative humidity of (50 ± 10)% of the standard environment Under conditions.

6 Operating

6.1 start package tangential direction to return 50m yarns to obtain a representative sample. With the thumb and forefinger of yarn, but not Take it off.

6.2 tangentially drawn 1m yarn as a sample, according to the 6.1, with the other hand and hold the other end of the sample, but do not cut off. The sample was vacant and forming an opening at both ends of the coil of 100mm apart.

6.3 Record opening coils twist self-inflicted (Ni) and twist the coil (S or Z). You can use the untwisting of the twist count method Slither.

1) per unit of product. the smallest unit of a commercially available usual delivery of products.

2) laboratory samples is part of the unit of the product, the product is not easy when the unit into the laboratory, take a laboratory sample, from which the desired and cut samples.