I. Manufacturing Process

Raw Materials: Large cross-section continuously cast billets (e.g., 320×480mm)

Forming: Through drilling, hot rolling, forging, and other processes

Heat Treatment: Quenching and tempering (quenching + high-temperature tempering), normalizing

Hardness Standard: Normalized state HRC32-35, Quenched and tempered state HRC49-57

II. Quality Grades (Classified by rock hardness coefficient f value)

Grade | Applicable Rock | Hardness Coefficient f

Superior Grade | Extremely hard rock | f ≥ 12 (Grade III and above)

Excellent Grade | Hard rock | f ≥ 12 (Grade IV and above)

Ordinary Grade | Medium hard and below | f ≤ 8 (Grade IV and below)

III. Usage Instructions

Must be used with a tapered drill bit.

The tapered drill rod itself does not have drilling capability and must be used with a tapered drill bit. Drill bit types include:

Chisel Bit: Suitable for soft to medium-hard rocks, high drilling speed

Cross Bit: Suitable for medium-hard to hard rocks, good wear resistance

Button Bit: Suitable for high-hardness, highly abrasive rocks, long service life

⚠️ Core Rule: The taper angles of the drill rod and drill bit must be consistent (e.g., a 7° drill rod must be paired with a 7° drill bit).

IV. Applicable Equipment

Mainly compatible with handheld pneumatic rock drills, such as models YT29, YT27, and YT28.

V. Selection Principles

Select the appropriate taper drill pipe based on the operating conditions:

Soft rock (f ≤ 8): Standard grade drill pipe + flathead drill bit, 7° taper

Medium-hard rock (f 8-12): Premium grade drill pipe + crosshead drill bit, 7° or 11° taper

Hard rock (f ≥ 12): Superior grade drill pipe + ball-tooth drill bit, 11° or 12° taper

Deep hole operations (>3m) Prefer H22 or higher specifications to ensure rigidity.

VI. Usage and Maintenance Points

Usage Precautions

Taper Fit Check: Ensure the drill rod and drill bit taper are consistent and tightly fitted to prevent loosening during operation.

Manual Pre-tightening: Tighten manually during installation; do not use the drilling machine to directly impact installation to prevent damage.

Matching Principle: The drill bit diameter should be larger than the drill rod diameter.

Abnormal Handling: If the drill gets stuck or jammed, stop drilling immediately or reverse the drill and slowly advance to prevent the drill rod from bending and deforming.

Maintenance Specifications

Regular Maintenance: Perform rust and dust prevention treatment according to the specified cycle.

Post-Operation Cleaning: After working in acidic or alkaline environments, clean the rod surface with clean water promptly to remove the corrosion layer.

Scrap Standard: Drill rods with excessive bending or damaged threads that cannot operate normally should be scrapped or returned to the factory for repair.

Storage Requirements

Store in a dry environment with multiple support points at the bottom.

Do not pile them randomly under gravel or coal piles.

After maintenance and cleaning, cover with a protective cap or pack and seal.

VII. Common Specification Quick Reference Table

Parameters

Common Specifications

Taper Angle

4°46' / 6° / 7° / 11° / 12°

Hexagonal dimensions: H19 / H22 / H25

Handle dimensions: 19×108 / 22×108 / 22×159 / 25×108 / 25×159 (mm)

Length range: 0.4m - 10m

Material: 55SiMnMo / 95CrMo / 23CrNi3Mo

Weight per piece: 1.7kg - 25kg (depending on length)