Drill pipe joints
Technical Specifications – Drill Pipe Tool Joints Range
The tables below present key specifications for our standard drill pipe joints. All tool joints comply with API Spec 7-1 requirements for dimensions, mechanical properties, thread gauging, and weld zone integrity.
API Standard Tool Joint Sizes & Connections
| Drill Pipe Size (in) | API Grade | Connection Type | Tool Joint OD (in/mm) | Tool Joint ID (in/mm) | Tong Space (in/mm) Box/Pin | Typical Application |
|---|---|---|---|---|---|---|
| 2‑3/8" | E75 / G105 | NC26 | 3.37 / 85.7 | 1.75 / 44.5 | 7 / 178 ; 8 / 203 | Slim hole, shallow wells |
| 2‑7/8" | E75 / G105 | NC31 | 4.12 / 104.8 | 2.00 / 50.8 | 9.1 / 232 ; 11 / 280 | Standard shallow drilling |
| 3‑1/2" | DZ50 / G105 | NC38 | 5.00 / 127 | 2.56 / 65.1 | 9.8 / 248 ; 12.2 / 310 | Medium depth, directional |
| 4" | G105 | NC40 | 5.91 / 150 | 2.56 / 65.1 | — | Medium‑deep drilling |
| 4‑1/2" | DZ50 / G105 | NC46 | 6.25 / 158.8 | 3.25 / 82.6 | 9.3 / 236 ; 12.6 / 320 | Deep drilling, heavy load |
| 5" | DZ50 / G105 | NC50 | 6.63 / 168.3 | 3.39 / 86.0 | 9.3 / 236 ; 12.6 / 320 | Deep drilling, heavy load |
| 5‑1/2" | G105 | 5‑1/2" FH | 7.25 / 184.2 | 3.62 / 92.1 | — | Heavy duty, offshore |
| 6‑5/8" | G105 | 6‑5/8" FH | 8.00 / 203.2 | 5.68 / 144.3 | — | Ultra‑deep, offshore |
API Drill Pipe Body Specifications (For Reference)
| Drill Pipe Size (in) | Nominal Weight (lb/ft) | ID (in) | Wall Thickness (in) | Grade Range | Connection (typical) |
|---|---|---|---|---|---|
| 2‑3/8" | 6.65 | 1.815 | 0.280 | E75–S135 | NC26 |
| 2‑7/8" | 10.40 | 2.151 | 0.362 | E75–S135 | NC31 |
| 3‑1/2" | 13.30 / 15.50 | 2.764 / 2.602 | 0.368 / 0.449 | E75–S135 | NC38 |
| 4" | 14.00 / 15.70 | 3.340 / 3.240 | 0.330 / 0.380 | E75–S135 | NC40 |
| 4‑1/2" | 16.60 / 20.00 | 3.826 / 3.640 | 0.337 / 0.430 | E75–S135 | NC46 |
| 5" | 19.50 / 25.60 | 4.276 / 4.000 | 0.362 / 0.500 | E75–S135 | NC50 |
| 5‑1/2" | 21.90 / 24.70 | 4.778 / 4.670 | 0.361 / 0.415 | E75–S135 | 5‑1/2" FH |
| 6‑5/8" | 25.20 / 27.70 | 5.965 / 5.901 | 0.330 / 0.362 | E75–S135 | 6‑5/8" FH |
Heavy Weight Drill Pipe (HWDP) Tool Joint Specifications (API 7-1)
| Nominal Size (in) | Pipe Body OD (in/mm) | Tool Joint Connection | Tool Joint OD (in/mm) | Tool Joint ID (in/mm) | Center Upset OD (in/mm) |
|---|---|---|---|---|---|
| 3‑1/2" | 3.50 / 88.9 | NC38 | 4.75‑5.00 / 121‑127 | 2.25 / 57.2 | 4.00 / 102 |
| 4" | 4.00 / 101.6 | NC40 | 5.25 / 133 | 2.50 / 63.5 | 4.50 / 114 |
| 4‑1/2" | 4.50 / 114.3 | NC46 | 6.25 / 159 | 2.69 / 68.3 | 5.00 / 127 |
| 5" | 5.00 / 127.0 | NC50 | 6.63 / 168 | 3.00 / 76.2 | 5.50 / 140 |
| 5‑1/2" | 5.50 / 139.7 | 5‑1/2" FH | 7.00‑7.50 / 178‑191 | 3.25 / 82.6 | 6.00 / 152 |
| 6‑5/8" | 6.63 / 168.3 | 6‑5/8" FH | 8.00‑8.50 / 203‑216 | 4.00 / 102 | 7.13 / 181 |
*HWDP specifications per API Spec 7-1 [9†L3-L10]. HWDP is manufactured from one‑piece AISI 4145H modified quenched and tempered steel and serves as a transition member between standard drill pipe and drill collars, providing weight on bit and additional stiffness to prevent buckling in directional wells. HWDP has a wall thickness increase of 2‑3 times that of standard drill pipe.*
Mechanical Properties – API Drill Pipe Grades
| Grade | Minimum Yield Strength (psi) | Minimum Tensile Strength (psi) | Maximum Yield Strength (psi) | Tool Joint Material |
|---|---|---|---|---|
| E‑75 | 75,000 | 100,000 | 105,000 | 4145H (110 ksi min yield) |
| X‑95 | 95,000 | 105,000 | 125,000 | 4145H (110 ksi min yield) |
| G‑105 | 105,000 | 115,000 | 135,000 | 4145H (110 ksi min yield) |
| S‑135 | 135,000 | 145,000 | 165,000 | 4145H Mod (135 ksi min yield) |
*Mechanical property data per API standards [11†L23-L25]. Tool joint steel typically has higher strength than the pipe body to ensure the connection is not the weak point in the drill string.*
Product Types – Complete Drill Pipe Joints Portfolio
As a comprehensive drill pipe joints supplier, we manufacture the following categories:
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Standard Drill Pipe Tool Joints – For API 5DP drill pipe, sizes 2‑3/8" to 6‑5/8". Connections: NC26, NC31, NC38, NC40, NC46, NC50, 5‑1/2" FH, 6‑5/8" FH. Grades E75, X95, G105, S135.
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Heavy Weight Drill Pipe (HWDP) Tool Joints – For integral and welded HWDP, sizes 3‑1/2" to 6‑5/8". Manufactured from one‑piece AISI 4145H modified quenched and tempered steel. Integral designs have the tool joint forged as part of the pipe body; welded types use friction welding.
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Non‑Magnetic Tool Joints – For MWD/LWD applications requiring magnetic permeability below 1.02. Fabricated from special non‑magnetic alloys to prevent interference with directional measurement tools.
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Sour Service (H₂S) Tool Joints – NACE MR0175 compliant, with controlled hardness and alloy chemistry to resist sulfide stress cracking and hydrogen embrittlement.
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Arctic / Low‑Temperature Tool Joints – Impact‑tested at ‑45°C or lower. Designed for drilling operations in the North Sea, Siberia, and other extreme cold environments.
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Spiral HWDP with Hardbanding – Heavy weight drill pipe with spiral outer contour and welded hardbanding on both tool joints and middle upset. The spiral design reduces friction and differential sticking.
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Premium Connection Tool Joints – Double‑shoulder designs for high torque extended‑reach drilling. Custom thread profiles and proprietary connections available.
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Special Length and Upset Options – Customized tool joint lengths (long or short configurations), special upset dimensions, and non‑standard drift diameters for specific wellbore clearance requirements.
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API 8C Lifting Subs & Crossovers – Specialized subs with handling grooves for lifting operations and crossover subs for connecting mismatched thread types.
Applications – Where Our Drill Pipe Joints Are Used
Our drill pipe joints are field‑proven across the full spectrum of drilling operations:
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Conventional onshore drilling – Standard NC tool joints for vertical wells. Our NC38 (3‑1/2" pipe), NC46 (4‑1/2" pipe), and NC50 (5" pipe) connections are the industry standard for most land drilling programs.
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Directional and horizontal drilling – HWDP tool joints provide transition stiffness between standard drill pipe and drill collars, reducing stress concentration and fatigue in the connection area. The thick wall of HWDP also reduces abrasion and fracture risk in deviated wells.
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Offshore platform drilling – Higher strength grades (G105, S135) and premium connections (FH series) for deepwater operations. 5‑1/2" FH and 6‑5/8" FH connections are common for large O.D. offshore drill strings.
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Extended reach drilling (ERD) – Heavy‑duty tool joints with high torque capacity are essential for long laterals exceeding 2,000 meters. Our S135 grade connections provide maximum torsional yield strength.
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Casing drilling – Tool joints for casing drilling strings require specific upset configurations and hardbanding to withstand wear against the previous casing string.
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Arctic drilling (‑45°C environments) – Low‑temperature impact‑tested tool joints prevent brittle fracture in extreme cold. Proven on multiple Rosneft drilling campaigns.
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Deep HP/HT wells (15,000+ ft, 15,000+ PSI) – Premium connections with metal‑to‑metal seals, high torque shoulders, and corrosion‑resistant alloys for sour gas environments.
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Heavy weight drill pipe (HWDP) applications – HWDP serves as a transition between standard drill pipe and drill collars, reducing stress concentration and fatigue in the connection area while providing weight on bit without the full stiffness of drill collars. The increased wall thickness (2‑3 times that of standard drill pipe) makes HWDP ideal for directional drilling.
Why Choose SJ Petro as Your Drill Pipe Joints Supplier?
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Sinopec‑backed manufacturing quality – As a direct subsidiary of China’s largest oilfield equipment group, we operate with the scale, resources, and technical depth (180,000+ m² manufacturing campus, 2,100+ machines, 314 R&D engineers) that independent tool joint manufacturers cannot match.
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API 7-1 certified across the range – Every tool joint is manufactured to API Specification 7-1. Third‑party inspection (ABS, DNV, BV, SGS) is always welcome at our facilities.
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Full material traceability – Each tool joint receives a unique serial number. We maintain complete material certificates (EN 10204 3.1) with heat numbers, chemical analysis, and mechanical test results. Traceability documentation is provided with every shipment.
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In‑house heat treatment and forging – We do not subcontract critical manufacturing steps. Our heat treatment facilities (quenching and tempering) and multi‑way hydraulic forge production lines are operated entirely by SJ Petro personnel, ensuring consistent quality and shorter lead times.
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Complete thread gauging – We maintain a full set of API master gauges for all NC, IF, FH, and REG connections. Each tool joint thread is gauged before shipment to ensure perfect interchangeability.
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100% non‑destructive testing (NDT) – Magnetic particle inspection (MPI) of every tool joint identifies surface cracks, laminations, and other defects. Ultrasonic thickness testing is also performed on critical sections.
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Global logistics network – We have shipped drill pipe tool joints to over 30 countries, including Russia, Kazakhstan, UAE, Saudi Arabia, India, Indonesia, and North Africa. Full export documentation — commercial invoice, packing list, bill of lading, Certificate of Origin — provided for every shipment. Our standard packing includes black painting, thread protectors, and secure bundling for container transport.
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Short lead times – Standard tool joints in common sizes (NC38, NC46, NC50, 5‑1/2" FH) are stocked for immediate shipment. Custom tool joints and HWDP sizes: 20‑30 days. Emergency rush orders can be expedited to 10‑15 days.
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Competitive direct‑manufacturer pricing – No trading company markups. You pay factory‑direct prices for Sinopec‑level quality, typically 15‑20% below Western brands for equivalent API certification and material grades.
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Warranty & technical support – 12 months warranty on all tool joints. Our in‑house technical team provides installation guidance, thread connection best practices, and failure analysis for any tool joint that does not meet performance expectations.
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Hardbanding and coating services – We apply hardbanding alloy to tool joint ODs on request, extending tool joint life in abrasive formations. Internal coating (TK34, TC2000, Arnco) is also available.
Frequently Asked Questions (FAQ)
Q1: What is a drill pipe tool joint and why is it important?
A drill pipe tool joint is the threaded connector at each end of a drill pipe. It consists of a box (internal threads at one end) and a pin (external threads at the other end). When pins mate with boxes, the drill pipe singles are joined into a continuous drill string. The tool joint must transmit the full tensile load (often exceeding 1 million lbs), all torque from the top drive, and provide a leak‑tight seal for drilling fluid circulation. A tool joint failure means a parted drill string — a very costly fishing job.
Q2: What is the difference between NC, IF, FH, and REG connections?
NC (Numbered Connections) are the modern standard. They are designated by the nominal pitch diameter in sixteenths of an inch (e.g., NC38 = 3.875" pitch diameter). NC connections have largely replaced older connection families. IF (Internal Flush) connections have a smooth bore with the same diameter as the pipe ID, minimizing flow turbulence. FH (Full Hole) connections have a larger ID than IF but smaller than pipe body. REG (Regular) connections are an older standard with a reduced ID, used primarily for larger drill collars and BHA components.
Q3: What is HWDP and why does it have special tool joints?
Heavy Weight Drill Pipe (HWDP) is a transitional drill string member between standard drill pipe and drill collars. Its wall thickness is 2‑3 times that of standard drill pipe. The tool joints on HWDP are usually larger in OD and incorporate thicker upset sections to handle the higher stress concentrations typical in the transition zone. HWDP tool joints are almost always supplied with hardbanding.
Q4: What do the numbers mean — NC38, NC46, NC50?
In NC (Numbered Connection) designations, the number refers to the nominal pitch diameter of the thread in sixteenths of an inch. NC38 = 38/16 = 2.375" pitch diameter (approximately 3.5" pipe). NC46 = 46/16 = 2.875" pitch diameter (approximately 4.5" pipe). NC50 = 50/16 = 3.125" pitch diameter (approximately 5" pipe). The numbers provide a universal specification that eliminates confusion with older named connections.
Q5: What material grades do you offer for tool joints?
Tool joints are typically manufactured from 4145H modified alloy steel, which exceeds the strength of the pipe body. For drill pipe, we supply tool joints matched to body grades E75, X95, G105, and S135. The API standard defines minimum yield strengths: E75 = 75,000 psi; X95 = 95,000 psi; G105 = 105,000 psi; S135 = 135,000 psi. For HWDP, 4145H is standard. Choose grade based on your expected tensile load and well depth.
Q6: What is hardbanding and do you provide it?
Hardbanding is a hard, wear‑resistant alloy welded onto the tool joint OD. It protects the tool joint from abrasive wear when rotating the drill string against the borehole wall, particularly in deviated and horizontal wells. We provide hardbanding in multiple alloy formulations (including proprietary ultra‑low friction alloys) on request. Hardbanding is strongly recommended for all HWDP and any tool joints run in abrasive formations.
Q7: What is the typical lead time for a tool joint order?
Standard tool joints (common sizes and connections, e.g., NC38, NC46, NC50 for 4‑1/2" and 5" drill pipe): 7‑14 days. Non‑standard sizes or custom upset configurations: 20‑30 days. HWDP tool joints (integral or welded): 30‑45 days. We maintain substantial finished‑goods inventory in our bonded warehouse for fast shipment.
Q8: What quality documentation do you provide?
Every shipment includes: material test certificates (EN 10204 3.1) with heat numbers, chemical composition, and mechanical properties; dimensional inspection report with API master gauge traceability; NDT report (MPI); and a certificate of conformance. For international shipments, we also provide commercial invoice, packing list, bill of lading, and Certificate of Origin (China).
Q9: Do you supply tool joints for drill pipe from other manufacturers?
Yes. We can match the thread type, OD, ID, and material grade of tool joints from any API‑compliant manufacturer. Provide a sample or detailed drawing, and we will manufacture drop‑in replacement tool joints. Our thread gauges cover all API connections as well as many proprietary designs.
