GB/T 1301-2025Hollow drill steels for rock drilling (English PDF)

1 Scope

This Document specifies the classification and code, ordering details, manufacturing process, technical requirements, test methods, inspection rules, packaging, marking, and quality certificate for hexagonal and round hollow steel used in rock drilling rods.

This Document applies to hexagonal and round hollow steel (hereinafter referred to as "hollow steel") used in rock drilling rods.

2 Normative References

The provisions in following documents become the essential provisions of this Document through reference in this Document. For the dated documents, only the versions with the dates indicated are applicable to this Document; for the undated documents, only the latest version (including all the amendments) is applicable to this Document.

GB/T 222 Permissible tolerances for chemical composition of steel products

GB/T 223.11 Iron, Steel and Alloys - Determination of Chromium Content - Titrimetric and Spectrophotometric Methods (GB/T 223.11-2025, ISO 4937.2024, MOD)

GB/T 223.14 Methods for chemical analysis of iron, steel and alloy - The N-benzoy-N- phenylhydroxylamine extraction photometric method for the determination of vanadium content

GB/T 223.23 Iron, steel and alloy - Determination of nickel content - The dimethylglyoxime spectrophotometric method

GB/T 223.25 Methods for chemical analysis of iron, steel and alloy - The dimethylglyoxime gravimetric method for the determination of nickel content

GB/T 223.26 Iron, steel and alloy - Determination of molybdenum content - The thiocyanate spectrophotometric method

GB/T 223.53 Methods for chemical analysis of iron, steel and alloy - The flame atomic absorption spectrophotometric method for the determination of copper content

GB/T 223.60 Iron, steel and alloy - Determination of silicon content - Gravimetric method (GB/T 223.60-2024, ISO 439.2020, MOD) technical standards of metallurgy

YB/T 5293 Metallic materials - Test method for upsetting

3 Terms and Definitions

For the purposes of this Document, the following terms and definitions apply.

4 Classification and Code

4.1 Hollow steel is classified into hexagonal and round shapes according to its shape.

4.2 Main specifications and codes are shown in Table 1.

4.3 Other specifications of hollow steels may also be provided upon negotiation between the supplier and the purchaser, and as specified in the contract.

Table 1 – Specifications and codes Unit. mm

Specifications and codes

5 Ordering Details

The order contract or order shall include at least the following.

a) This Document number;

b) Product name;

c) Designation;

d) Controlled residual elements (if required);

e) Weight (or quantity) of the delivered product;

f) Specification code and dimensional tolerance level;

g) The used processing method (if required);

h) Length;

i) Other special requirements.

6 Manufacturing Process

6.1 The billet used for producing hollow steel shall be vacuum degassed.

6.2 Hollow steel core holes may be machined by drilling, piercing, and punching.

6.3 Hollow steel is usually delivered in hot-rolled condition; but may also be delivered in heat- treated condition (annealed, normalized, or high-temperature tempered) condition upon the purchaser's request and specified in the contract.

6.4 Hollow steel shall not exhibit overheated or burnt structures.

6.5 The inner lining tube of hollow steel shall not be loose or fall off.

7 Technical Requirements