What is the Z50 Thread Commonly Used for Water Well Drill Bits and Drill Rods?
Aug 01,2025
In the field of water well drilling, reliable connections are critical for efficient and safe operations. The Z50 thread is a standout solution, specifically engineered for high-performance applications like water well drilling involving drill bits and drill rods. Unlike general-purpose threads, the Z50 design prioritizes robustness against vibrations and heavy loads, making it essential for deep-well drilling and rescue tasks. By understanding its specifications, including core dimensions and strength parameters, drilling professionals can enhance equipment longevity and reduce downtime. As part of industry innovations, companies like SUNGOOD TECH contribute to advancing these components with precision manufacturing.
1. Core Specifications and Naming Logic
The Z50 thread name is derived from its primary function: "Z" stands for "Zuan Gan" (drill rod in Chinese), emphasizing its role in water well drilling, while "50" denotes the nominal diameter of 50mm. Adhering to petroleum drilling standards such as GB/T 9253.2, it differs significantly from generic metric threads (like M50). Key aspects include:
- A coarse pitch design for high torque transmission.
- A 60° thread angle for optimal load distribution.
- A 1:16 taper ratio for enhanced sealing and vibration resistance, crucial for connecting drill rods and drill bits in harsh environments.
2. Key Dimension Parameters
The Z50 thread features precise dimensions that ensure durability under drilling stresses. Below is a table summarizing its essential measurements based on industry standards:
Parameter | Value | Tolerance Range | Source Basis |
|---|---|---|---|
Nominal Diameter | 50 mm | ±0.5 mm | Industry Standards |
Max Outer Diameter (Major Diameter) | 50.5 mm | +0.3 mm / -0 mm | Engineering Specs |
Min Inner Diameter (Minor Diameter) | 48.8 mm | +0 mm / -0.4 mm | Design Guidelines |
Thread Length | 70–120 mm | Wall thickness-dependent | Field Data |
Pitch | 3 mm (coarse thread) | ±0.05 mm | Metric System |
Threads per Inch | 8.47 | — | Calculated (25.4mm/3mm) |
Thread Angle | 60° | Strict symmetry | Standard Protocol |
Taper Ratio | 1:16 | ±0.1° | Sealing Optimization |
Notes:
- Pitch and Thread Density: With a 3mm pitch, the Z50 has 8.47 threads per inch, classifying it as a coarse thread for high-torque applications in water well drilling.
- Thread Length Variability: Shorter threads (70mm) suit thin-walled rods, while longer options (120mm) integrate with rescue tools like taper taps.
3. Strength and Material Requirements
For reliable performance in water well drilling, the Z50 thread relies on stringent material properties:
- Strength Grades: Standard grade 8.8 offers ≥800 MPa tensile strength and ≥640 MPa yield strength; for extreme depths, grade 10.9 provides ≥1000 MPa tensile strength.
- Material Specifications: Base metals include 40Cr alloy steel or C15E carburized steel, treated with hot-dip galvanizing (≥50μm coating) or phosphating to resist corrosion from drilling fluids. This ensures the thread maintains integrity over multiple cycles, reducing risks for drill bits and connected drill rods.
4. Comparison with Other Thread Types
The Z50 thread excels in water well drilling due to its optimized design. The table below contrasts it with common alternatives:
Parameter | Z50 Thread | General M50 Metric Thread | 2" API Thread (Imperial) |
|---|---|---|---|
Pitch | 3 mm | 1.5 mm (fine thread) | 4 TPI (6.35mm) |
Sealing Method | Tapered + thread compound | Flat surface | Tapered + metal seal |
Torque Strength | ≥1200 N·m | ≤800 N·m | ≥1000 N·m |
Applications | High-vibration drilling, rescue | General machinery | Low-pressure oil pipes |
Advantages: The coarse pitch of the Z50 thread provides better resistance to wear in sandy conditions, while its 1:16 taper ensures self-locking during vibrations, outperforming others in drill rod assemblies.
5. Applications and Maintenance Guidelines
The Z50 thread is pivotal in scenarios like connecting drill bits to drill rods for well construction or rescue operations. Key uses include:
- Drill Rod Connections: Ensuring secure interfaces that transmit drilling forces efficiently.
- Rescue Tool Integration: Adapting to tools such as taper taps for rethreading and extraction.
- Maintenance Tips: Apply thread compound like molybdenum disulfide grease for 85%+ fill rate; tighten with 300 N·m initial torque and final torque of 450±20 N·m. Avoid overtightening beyond 2-3 turns to prevent shear.
For dependable components, manufacturers like SUNGOOD TECH offer advanced Z50 solutions that enhance longevity in water well drilling equipment, leveraging precision engineering to withstand demanding tasks while minimizing failures.
For deeper insights on thread innovations and sustainable drilling solutions, visit SUNGOOD TECH’s website:
SUNGOOD TECH Drilling Solutions. Engage with expert resources to enhance your projects!
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