SHUNFU METAL utilizes AISI 4145H alloy steel for manufacturing Kelly bars, which is specifically designed for high-stress drilling applications. This premium alloy steel provides exceptional strength, toughness, and wear resistance characteristics essential for demanding drilling operations.
Kelly bars are positioned at the top of the drill string and are available in both square and hexagonal configurations. As a leading manufacturer, SHUNFU METAL specializes in producing high-quality Kelly bars that serve as the critical link between the rotary table and the entire drill string system. The primary function of Kelly bars is to transmit the rotational motion from the rotary table to the entire drill string and drill bit for formation breaking, effectively transferring torque while supporting the complete weight of the drill string.
SHUNFU METAL’s square and hexagonal Kelly bars are manufactured using premium AISI 4145H alloy steel with full-length heat treatment processing. This advanced manufacturing approach ensures consistent mechanical properties throughout the entire length of the product, providing superior performance and reliability in demanding drilling operations. Our products exhibit excellent Brinell hardness ranging from 285 to 341 HB and Charpy impact energy of 54J, with these physical properties guaranteed at 1 inch below the tube surface.
Key Applications and Functions
The Kelly bars manufactured by SHUNFU METAL are essential components in rotary drilling operations, serving multiple critical functions including torque transmission from the rotary table to the drill string, supporting the entire weight of the drill string assembly, and providing the necessary rotational motion for efficient drilling operations. These products are widely used in oil and gas exploration, water well drilling, geothermal drilling, and various construction and mining applications.
SHUNFU METAL ensures that all Kelly bar ends and drive sections, including internal dimensions and connections, are machined and inspected according to API Spec 7-1 or SY/T 6509-2000 standards. This adherence to international standards guarantees compatibility with existing drilling equipment and ensures optimal performance in various drilling environments worldwide.
Chemical Composition Section
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High-Performance AISI 4145H Steel from SHUNFU METAL
Introduction Section
AISI 4145H Alloy Steel Composition
| Element | Carbon (C) | Silicon (Si) | Manganese (Mn) | Chromium (Cr) | Molybdenum (Mo) |
|---|---|---|---|---|---|
| Typical Range (%) | 0.43-0.48 | 0.15-0.35 | 0.75-1.00 | 0.80-1.10 | 0.15-0.25 |
Heat Treatment Process
SHUNFU METAL employs comprehensive heat treatment processes including full-length quenching and tempering of AISI 4145H alloy bars. This advanced heat treatment ensures uniform hardness distribution and optimal mechanical properties throughout the entire length of the Kelly bar. The process guarantees hardness levels of 285-341 Brinell hardness at one inch below the surface according to ASTM A370 standards, with Charpy impact energy exceeding 54J.
Available Types Section
Available Kelly Types from SHUNFU METAL
Square Kelly Bars
Hexagonal Kelly Bars
Square Kelly Bars with Wear Protection
Available Shapes and Configurations
Four-Sided Kelly
Six-Sided Kelly
Custom Kelly Configurations
Available Sizes – Square Kelly Bars
SHUNFU METAL offers a comprehensive range of square Kelly bar sizes to meet diverse drilling requirements. Our standard size options ensure compatibility with various drilling systems and operational needs.
| Size | Length (ft) |
Standard L₀ (ft) |
Max L (ft) |
Inside Diameter D₀” (in) |
Square Dimension D₁” (in) |
Square Dimension D₀” (in) |
Pin End R₀ (in) |
Box End R₁₀ (in) |
Weight per Unit (t) |
|---|---|---|---|---|---|---|---|---|---|
| 2 1/2 | 37 | — | 40 | — | 2 1/2 | 3 9/32 | 3.25 | 5/16 | 0.450 |
| 3 | 37 | 51 | 40 | 54 | 3 | 3 15/16 | 3.875 | 3/8 | 0.450 |
| 3 1/2 | 37 | — | 40 | — | 3 1/2 | 4 17/32 | 4.437 | 1/2 | 0.450 |
| 4 1/4 | 37 | 51 | 40 | 54 | 4 1/4 | 5 9/16 | 5.500 | 1/2 | 0.475 |
| 5 1/4 | 37 | 51 | 40 | 54 | 5 1/4 | 6 29/32 | 6.750 | 5/8 | 0.625 |
Available Sizes Section – Hexagonal Kelly
Available Sizes – Hexagonal Kelly Bars
SHUNFU METAL’s hexagonal Kelly bars offer enhanced torque transmission capabilities with six-sided configurations. These products provide superior performance in high-torque drilling applications.
| Size | Length (ft) |
Standard L₀ (ft) |
Max L (ft) |
Inside Diameter D₀ (in) |
Hexagonal Dimension D₁ (in) |
Hexagonal Dimension D₀ (in) |
Pin End R₀ (in) |
Box End R₁₀ (in) |
Weight per Unit (t) |
|---|---|---|---|---|---|---|---|---|---|
| 3 | 37 | — | 40 | — | 3 | 3 3/8 | 3.375 | 1/4 | 0.475 |
| 3 1/2 | 37 | — | 40 | — | 3 1/2 | 3 31/32 | 3.937 | 1/4 | 0.525 |
| 4 1/4 | 37 | 51 | 40 | 54 | 4 1/4 | 4 13/16 | 4.781 | 5/16 | 0.625 |
| 5 1/4 | 37 | 51 | 40 | 54 | 5 1/4 | 5 31/32 | 5.900 | 3/8 | 0.625 |
| 6 | 37 | 51 | 40 | 54 | 6 | 1 13/16 | 0.622 | 0.623 | 0.625 |
Extended Length Capabilities
SHUNFU METAL can provide Kelly bars up to 16 meters in length, offering exceptional flexibility for various drilling applications. We maintain regular inventory of standard sizes and welcome inquiries for immediate pricing and availability.
We also accept custom orders and invite you to consult with our technical team regarding specific dimensional requirements and manufacturing capabilities to meet your unique drilling needs.
Mechanical Properties Section
Mechanical Properties
SHUNFU METAL’s Kelly bars manufactured from AISI 4145H alloy steel exhibit exceptional mechanical properties that ensure reliable performance in demanding drilling conditions. The comprehensive heat treatment process guarantees consistent properties throughout the material.
| Outer Diameter Range | Tensile Strength (MPa) |
Yield Strength (MPa) |
Elongation δ4 (%) |
Charpy Impact AKV (J) |
Brinell Hardness (HB) |
|---|---|---|---|---|---|
| 79.4-171.4 mm (3 1/8″ – 6 3/4″) |
≥965 | ≥758 | ≥13 | ≥54 | ≥285 |
| 177.8-279.4 mm (7″ – 11″) |
≥930 | ≥689 | ≥13 | ≥54 | ≥285 |
Quality Assurance and Testing
SHUNFU METAL implements comprehensive quality control measures throughout the manufacturing process. All raw materials used for Kelly bar production undergo magnetic particle inspection and ultrasonic testing. The entire length and cross-section of finished products are subjected to ultrasonic inspection, and the drive section thickness is also ultrasonically tested to ensure structural integrity.
Surface Protection and Performance Enhancement
To enhance friction resistance and extend service life, all threads on SHUNFU METAL’s Kelly bars are coated with API thread compound. This protective coating ensures smooth assembly and disassembly operations while preventing galling and extending the operational life of the threading connections. The surface treatment also provides additional protection against corrosion in harsh drilling environments.
Heat Treatment Section
Heat Treatment and Manufacturing Process
Full-Length Heat Treatment
Precision Manufacturing
Quality Control Standards
Why Choose SHUNFU METAL for Kelly Bars
Premium Materials
API Compliance
Extended Lengths
Complete Protection
Contact SHUNFU METAL Today
Ready to discuss your Kelly bar requirements? Contact our technical sales team for detailed specifications, pricing, and delivery information. SHUNFU METAL is your trusted partner for premium drilling equipment solutions.
We are committed to integrate steel resources in china and serve the global steel market. Our company has more than 15 years of experience in steel researching, production, managing and sales. And our team mostly are based on and worked in national famous steel enterprise before. In the aspect of resources and information, we have established cooperative relationship with nearly hundred enterprises, either state-owned or private owned in China.
What’s more, we have built long, deep and close business relationship with dozens of steel company, Sharing and holding equities with several steel enterprises. Because of the close cooperation with steel companies and our pioneering spirit, which can ensure us stay at the top competition, and ensure our customers get what they really want. We provide preffesional one-stop service to the Contractors of follows project:
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Oil and Gas Pipeline Construction
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Onshore and Offshore
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Boiler Manufacturers
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Oil Refining Equipment
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Petroleum and Chemical Plant Construction
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Fire Protection
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Heating & Air Conditioning
Our ability to purchase materials directly from leading mills at the best possible price will give you the competitive edge. This coupled with a skilled workforce dedicated to embracing the demands of the markets we serve. Just give us a call +86-731-89903933.
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