Drill Pipe Specification
API Standard: API Spec 5DP / ISO 11961
Steel Grades: E75, X95, G105, S135
Outer Diameter (OD): 2 3/8″ to 6 5/8″
Pipe End Upsets: Internal Upset (IU), External Upset (EU), Internal-External Upset (IEU)
Tool Joints: NC26, NC31, NC38, NC46, NC50, 5 1/2 FH, 6 5/8 FH (Cold Rolled Root Threads)
Quality Level: PSL-1,PSL-2 or PSL-3 available according to API Spec 5DP requirements
Optional Service:
Sour Service Drill Pipe (H2S Service) available upon request,Aluminum Alloy Drill Pipe.
Stock Availability:
Selected 3 1/2″, 4″, 4 1/2″ and 5″ Range 2 drill pipes available for short lead-time delivery, subject to current inventory.
Submit a procurement request to obtain the drill pipe inventory list.
Drill pipe is the basic structural element of the drill string, manufactured from seamless steel pipe with a typical wall thickness of 9-11mm. Its primary function is to transmit torque to the drill bit and circulate drilling fluid down the wellbore — making it one of the most critical components in the entire drilling operation.
Mitigating Drilling Risks: The ELITE® API 5DP Drill Pipe Manufacturing Blueprint
Sourcing drill pipe isn’t just about matching dimensions; it’s about guaranteeing operational uptime under extreme torque and high-fatigue drilling dynamics. Every length of drill pipe supplied by ELITE is engineered to survive the world’s most demanding oilfield environments.
Our Industrial Sourcing Commitments to Procurement Teams:
API Spec 5DP Certified Traceability: 100% of our drill strings are manufactured strictly compliant with API 5DP specifications, delivered with complete Material Test Certificates (MTC) traceable back to the steel heat number.
Advanced Inertia Friction Welding: The transition zone between the pipe body and the tool joint is joined via computer-controlled inertia friction welding, followed by 100% full-body heat treatment to eliminate structural stress zones.
Premium Steel Grades Ready: Available from standard Grade E-75 up to high-tensile Grade S-135, optimized with premium internal upset (IU), external upset (EU), or internal-external upset (IEU) configurations.
Hardbanding & Internal Plastic Coating (IPC): Optional premium hardbanding (Arnco, Duraband) and IPC (TC2000, TK34) to maximize wear resistance against abrasive formations and corrosive drilling fluids.
Streamline Your Drill String RFQ
Are you finalizing a procurement tender or replacing a worn-out drilling fleet string? Use our factory-direct technical channel below:
Need direct pricing for commercial strings (e.g., 4-1/2″ S135)?
Request an Instant Fleet-Pricing Quote Submit your size, grade, and connection profiles for a 24-hour commercial proposal.
Reviewing full dimension limits, wall thickness, and weights?
Download API Drill Pipe Technical Catalog Get immediate access to comprehensive engineering datasheets and crossover specifications (PDF).
Send your complete Bill of Materials (BOM) directly to our strategic corporate sourcing desk at info@apidrillpipe.com （WhatsApp: +86 18615995257） for a priority engineering review.
Drill pipe structure and specification
The drill pipe is composing of seamless steel pipes, and the wall thickness is generally 9~11mm.
It consists of two parts: the drill pipe body and the drill pipe joint.
Drill pipe body and tool joints can be connected in two ways. The older method uses fine-thread (“button”) connections, threaded directly onto both ends of the pipe body. The modern and now industry-standard method is friction welding, where the tool joint is welded to the pipe body under controlled heat and pressure – known as “upset welding” or “flash welding” drill pipe.
Fine-thread connections have been largely phased out across the industry.Virtually all drill pipe manufactured today, including ELITE’s full product range, uses friction-welded tool joints for superior fatigue resistance and connection integrity.
Supplement | Knowledge
In order to enhance the connection strength between the pipe body. And the joint, both ends of the pipe body are thickening.
Commonly used thickening forms are internal thickening, external thickening, and internal and external thickening.
According to the regulations of the American Petroleum Institute (API-American Petroleum Institute), drill pipe is dividing into three categories by length:
- R1 ：5.486~6.706m(18~22ft)；
- R2：8.230~9.144m(27~30ft)；
- R3:11.582~13.716m(38~45ft)；
The most commonly used drill pipe sizes are 88.9 (3.5in), 114.3 (4.5in), and 127.0mm (5in).
The outer diameter of the drill pipe joint is larger than the outer diameter of the pipe.
During the drilling process, it is constantly in contact. And friction with the well wall or casing, resulting in wear. Equipped with drill pipe joint wear belt.
ELITE Quality Assurance & Inspection (PSL-1, PSL-2, PSL-3)
All drill pipes undergo strict non-destructive and destructive testing to ensure compliance with API Spec 5DP quality control levels:
Full Body Ultrasonic Testing (UT): 100% full-length ultrasonic flaw detection for pipe body wall thickness and laminations.
Weld Zone Inspection: 100% Magnetic Particle Inspection (MPI) and UT on friction-welded joint areas.
Thread Inspection: API Spec 7-2 thread gauging and optical profile inspection.
Mechanical Testing: Full lot tensile, yield, Charpy V-Notch impact testing, and hardness testing per heat number.
Certificates Supplied: EN 10204 3.1 Mill Test Certificate (MTC), Third-Party Inspection Reports (SGS, BV, Intertek, Lloyd’s) available upon request.
Grade and strength of oil drill pipe
Drill pipe steel grade is defined by the minimum yield strength of the material. API specifies five standard grades: D, E-75, X-95, G-105, and S-135 — with X, G, and S grades classified as high-strength drill pipe.
Higher steel grades deliver greater yield strength and, correspondingly,higher tensile, torsional, and collapse resistance. When designing a drill string for higher-stress applications, ELITE’s engineering team generally recommends increasing steel grade rather than wall thickness — this preserves internal bore diameter for fluid flow while still achieving the required strength margin.
Why Drill Pipe Size Alone Is Not Enough
Two drill pipes with the same outside diameter may have different:Nominal weights,Wall thicknesses,Inside diameters,Steel grades,Upset types,Tool joint dimensions,Connections,Finished weights,Torque capacities,Internal coatings,Hardbanding systems.
For example, a request for “5-inch S135 drill pipe” is still incomplete unless the nominal weight, range, connection and tool joint dimensions are confirmed.
When comparing quotations, require each supplier to provide a complete technical data sheet rather than only a product description.
How to Compare API Drill Pipe Quotations
Do not compare quotations using only the price per joint.
Check the following items line by line.
Technical Configuration
Outside diameter,Nominal weight,Wall thickness,Grade,Range,Upset type,Connection,Tool joint OD,Tool joint ID,Finished length,Approximate joint weight.
Manufacturing Scope
Pipe body manufacturer.Tool joint manufacturer.Upsetting location.Heat-treatment location.Friction-welding location.Threading location.Hardbanding applicator.Internal-coating applicator.
Inspection Scope
Material test certificate,Chemical composition,Mechanical properties,Heat-treatment records,Full-length NDT,Weld-zone inspection,Tool joint inspection,Thread gauging,Hardness report,Dimensional report,Traceability list.
Commercial Scope
Price per joint,Included hardbanding,Included internal coating,Thread protectors,Export packing,Inspection cost,Third-party inspection cost,Incoterm,Freight,Production lead time,Offer validity,Warranty,Claim procedure.
A lower quotation may exclude internal coating, hardbanding, inspection reports, export packing or third-party inspection.
Ask every supplier to list all deviations and exclusions in writing.
Why Procurement Teams Source Drill Pipe From ELITE
Since 2006 — Taizhou ELITE Drilling Pipe Co., Ltd. has manufactured API 5DP drill pipe for 20+ years, with $30M+ invested in production capacity.
Global Service Network — Branches in the USA and Thailand, with service outlets across 8 regions worldwide.
Full Traceability — Every drill pipe ships with Material Test Certificates (MTC) traceable to the steel heat number.
Complete Grade Range — E-75 through S-135, with IU/EU/IEU upset
configurations and optional hardbanding (Arnco, Duraband) or internal plastic coating (IPC).
[Request a Quote →]
info@apidrillpipe.com
+86 18615995257
