GB/T 43550.2-2023Mechanical pencils and leads for general use - Classification, dimensions, quality and test methods - Part 2: Black leads (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 2 of GB/T 43550 "Classification, Dimensions, Quality and Test Methods of Mechanical Pencils and Leads for General Purposes":

GB/T 43550 has published the following parts:

---Part 1: Mechanical Pencil;

---Part 2: Black lead core:

This document is equivalent to ISO 20318-2:2019 "Classification, Dimensions, Quality and Test Methods for Mechanical Pencils and Leads for General Purposes" Part 2: Black Lead Core:

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

Introduction

Mechanical pencils are one of the most popular writing tools among consumers: In recent years, general-purpose mechanical pencils have become increasingly popular among students:

Welcome, and with different use occasions, the types of lead core hardness and diameter are also increasing: It is worth noting that the mechanical pencil presents an overall the output is increasing year by year, but the output of mechanical pencils used for technical drawing is on a downward trend: Scope of application of GB/T 39542 (all parts) the scope is limited to technical drawing mechanical pencils and lead to clearly differentiate between mechanical pencils and lead for two different uses: Therefore, for technical drawing Mechanical pencils are different, and documentation is necessary for general purpose mechanical pencils and refills:

GB/T 43550 is intended to consist of two parts:

---Part 1: Mechanical Pencil: The purpose is to establish quality requirements and test methods suitable for general-purpose mechanical pencils:

---Part 2: Black lead core: The purpose is to establish quality requirements and test methods for black lead cores for general-purpose mechanical pencils:

Since the release of the standard for technical drawing mechanical pencils and refills, two issues have not been resolved: One is mechanical pencil and lead packaging the markings on the product indicate that lead cores with nominal diameters of 0:35mm and 1mm are marked as 0:3mm and 0:9mm respectively: This paper attempts to accurately determine Define the diameter to solve the sign problem: Second, there is currently no scientific definition of hardness grade: Although this paper attempts to establish a purely quantitative assessment methods, but qualitative assessment is still needed: This issue is not addressed in this paper:

General purpose mechanical pencils and lead classifications, sizes, Quality and test methods Part 2: Black lead core

1 Scope

This document specifies the classification, size and quality requirements for black lead for general purpose mechanical pencils specified in ISO 20318-1, and describes Corresponding test methods:

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:

technology-Densitymeasurements-Part 3:Spectralconditions) Note: GB/T 11501-2008 Photographic density measurement Part 3: Spectral conditions (ISO 5-3:1995, IDT) General use) Note: GB/T 26714-2019 Ink ballpoint pens and refills (ISO 12757-1:2017; ISO 12757-2:1998, MOD) General use) Note: GB/T 32017-2019 Water-based ink ballpoint pens and refills (ISO 14145-1:2017; ISO 14145-2:1998, MOD) ISO 20318-1 Classification, dimensions, quality and test methods of mechanical pencils and lead for general use Part 1: Mechanical pencils Part 1:Mechanical pencils) Note: GB/T 43550.1-2023 Classification, dimensions, quality and test methods of mechanical pencils and lead for general use Part 1: Mechanical pencils (ISO 20318-1:2019,IDT)

3 Terms and definitions

The terms and definitions defined in ISO 20318-1 and the following apply to this document:

ISO and IEC maintain terminology databases used for standardization at:

---ISO online browsing platform: available from https://www:iso:org/obp;

black lead core blacklead A solid writing material containing carbon (such as graphite) and a binder that produces erasable black lines: