GB/T 39024-2020Black leads for wood-cased pencils--Classification and diameters (English PDF)

Foreword

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

The translation method used in this standard is equivalent to ISO 9180.1988 "Classification and Diameter of Wooden Pencil Black Lead".

This standard was proposed by the China National Light Industry Council.

This standard is under the jurisdiction of the National Pen Standardization Technical Committee (SAC/TC378).

Drafting organizations of this standard. Shanghai Institute of Pen Industry, China First Pencil Co., Ltd., Anshuo Stationery (Shanghai) Co., Ltd.

the company.

1 Scope

This standard specifies the classification and diameter of the black lead core of wooden pencil pencils.

2 Terms and definitions

The following terms and definitions apply to this document.

2.1

Blacklead

Containing carbon (such as graphite) and adhesive, the resulting black stitches are erasable solid writing materials.

2.2

Hardnessdegree

Represents the classification level with increasing hardness from 6B to 9H, and increasing stitch concentration from 9H to 6B.

Note. There is no scientific definition of hardness level.

2.3

Wood-casedpencil

A hand-held writing tool with a lead core fixed in the barrel made of wood and capable of withstanding the force of writing.

3 categories

Lead cores are divided into the following 17 types according to their hardness levels.

9H, 8H, 7H, 6H, 5H, 4H, 3H, 2H, H, F, HB, B, 2B, 3B, 4B, 5B and 6B.

4 diameter

The diameter of the lead core should meet the requirements of Table 1.

Table 1 Diameter

Hardness grade (see 2.2) Lead core diameter/mm

9H, 8H, 7H, 6H, 5H, 4H, 3H, 2H, H >=1.8

F, HB, B, 2B, 3B, 4B, 5B, 6B >=2.0