GB/T 14345-2003 in English

《GB/T 14345-2003合成纤维长丝捻度试验方法》由608（中国纺织工业联合会）归口，主管部门为中国纺织工业联合会。
本标准规定了合成纤维长丝捻度的试验方法。本标准适用于具有捻度的合成纤维复丝、合股变形丝及股线的试验。

Testing method for twist of synthetic filament yarns

1 Scope

This standard specifies the testing method for twist of synthetic filament yarns.

This standard is applicable to the testing of synthetic fiber multifilament, plying textured filament yarns and plied yarns with twist.

2 Normative references

The following documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments to (excluding any corrigendum), or revisions of, any of these publications do not apply. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the latest editions of the standards indicated below. For undated references, the latest edition of the document referred to applies.

GB/T 3291.1-1997 Textiles—Terms of textile material properties and test—Part 1: Fibre and yarn
GB/T 3291.3-1997 Textiles—Terms of textile material properties and test—Part 3: General
GB/T 6502-2001 Sampling method for synthetic filament yarns
GB 6529-1986 Standard atmospheres for textiles conditioning and testing
GB/T 8170 Rules for rounding off of numerical values

3 Terms and definitions

For the purposes of this standard, the terms and definitions given in GB/T 3291.1-1997 and GB/T 3291.3-1997 as well as the following apply.

3.1
twist
number of twisting turns of filament in a certain length along the axial direction

3.2
twist direction
inclination direction of the monofilament in the multifilament or the multifilament in the plied yarns after twisting, which is marked with S or Z


4 Principle

Under a certain tension, one end of the sample is fixed and the other end is rotated to remove the twist of the filament yarn within the specified length until the components in the monofilament or piled yarns in the multifilament are parallel. Then the twist direction is observed and the twist is calculated.

5 Apparatus and materials

5.1 Twist meter, which shall be equipped with:

a) Two grippers, one of which can rotate in clockwise and counter-clockwise directions, and whose specified starting length position can be adjusted;

b) Rotary counter, the number of revolutions shall be accurate to the nearest one;

Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Apparatus and materials
6 Standard atmosphere for conditioning and testing
7 Sample and its preparation
8 Testing methods
9 Expression of results
Annex B (Informative) Method for calculating pretension