Large Diameter DTH Drill Pipes for Foundation & Piling Projects

Rock Drilling Tools

Large Diameter DTH Drill Pipes

Applicable hole diameter: 305-1200mm
Thread connection types: NUMA 120/180/240; API REG
Material: Low-carbon alloy steel

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Typical Applications

Rock socket drilling in foundation engineering projects, including building piles, bridge piles, metro construction, and other infrastructure foundation works.

Industrial plant foundations

Land reclamation and offshore foundation projects

Technical Specifications

Model	Outer diameter	Adapter type	Length
426mm drill pipe	426mm	273 hexagonal	1000-9000mm
450mm drill pipe	450mm	273 hexagonal	1000-9000mm
508mm drill pipe	508mm	273 hexagonal	1000-9000mm
610mm drill pipe	610mm	273 hexagonal	1000-9000mm
711mm drill pipe	711mm	320 hexagonal	1000-9000mm
813mm drill pipe	813mm	320 hexagonal	1000-9000mm
914mm drill pipe	914mm	320 hexagonal	1000-9000mm

Key Advantages

Excellent interchangeability: All connections are designed according to NUMA-standard hexagonal joints, ensuring high interchangeability with mainstream large-diameter DTH systems.
Customizable length range: Drill pipe lengths can be customized from 1m to 12m, allowing flexible configuration to suit different drilling depths and rig setups.
Hexagonal quick-connection design: The hexagonal male-female joint design significantly reduces make-up and break-out time.
Due to the heavy weight of large-diameter drill pipes, installation is typically assisted by a crane. Once the hex joint is properly aligned, the pipe is secured with a locking pin, enabling fast, safe, and reliable installation.
Excellent air sealing performance: The drill pipes provide reliable air sealing with minimal leakage, making them well suited for DTH drilling operations using high-capacity air compressors.
Optimized pipe diameter for air efficiency: The pipe diameter is designed to closely match the drill bit diameter, improving air utilization efficiency during drilling and reducing compressor air consumption, thereby lowering overall operating costs.

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How is the appropriate drill pipe selected?

The drill pipe diameter should be selected to closely match the drill bit diameter in order to ensure efficient air flow and stable drilling performance. For formations dominated by hard rock, double-wall drill pipes are recommended, as they provide improved air delivery and structural strength. In formations containing large amounts of sand, gravel, or soil, spiral drill pipes are more suitable due to their enhanced cuttings removal capability.

How are large diameter DTH drill pipes maintained?

Before drilling, after the drill pipe is connected to the drilling rig, compressed air should be blown through the pipe to remove any internal debris. This prevents contaminants generated during manufacturing or transportation from entering the DTH hammer and affecting its service life. After use, drill pipes should be stored in a dry and well-ventilated environment. When conditions permit, applying a protective oil coating to the outer surface is recommended to help prevent corrosion and extend service life.