Project Description
AISI 4140 Modified Steel
AISI 4140 Modified is an advanced chromium-molybdenum (CrMo) alloy steel engineered for critical, high-stress environments. By featuring enhanced chromium and molybdenum levels, this grade delivers superior hardenability, exceptional through-section properties, and outstanding wear resistance compared to standard 4140.
As an API Q1 and ISO 9001 certified manufacturer, ShunFu Metal specializes in producing this premium grade specifically for the demanding oil & gas and mining sectors. Backed by over a decade of export experience to more than 50 countries, we proudly supply AISI 4140 Modified steel to the world’s top 10 oilfield service companies — learn more about our quality commitment — guaranteeing uncompromising material integrity for the most severe downhole operations.
Equivalent Grades
| Standard | Grade / Designation |
|---|---|
| AISI / SAE | 4140 Modified / 4140M |
| UNS | G41400 (Modified) |
| EN / DIN | 42CrMo4 (Modified) / 1.7225 (Modified) |
Applications
Tool Joints & Crossover Subs (Oil & Gas)
Supplied by ShunFu Metal as precision CNC-machined components or forged blanks. We utilize a high forging reduction ratio (minimum 4:1) to ensure optimal grain flow and exceptional fatigue resistance in drill string assemblies.
Drill Collars & Shock Subs (Drilling)
Delivered as heavy-walled tubulars or pre-drilled hollow bars. ShunFu Metal uses in-house BTA deep-hole drilling and rigorous heat treatment to achieve the exact 80ksi to 125ksi yield strengths required for drill collars and shock subs.
High-Stress Gears & Power Transmission Shafts (Mining)
Provided as peeled or smooth-turned round bars. Our precise chemistry control during the melting process ensures the superior wear resistance and toughness needed for extreme load-bearing machinery.
Top Drive Components & Stabilizers (Oil & Gas)
Supplied as custom-forged blocks or cylinders. ShunFu Metal performs 100% ultrasonic testing (UT) to API 6A PSL 3&4 standards on these parts to guarantee zero internal defects before machining.
Specifications & Standards
ShunFu Metal strictly organizes production according to the following standards and provides fully traceable material test certificates (MTC) corresponding to your required specifications.
- ASTM A29 / A29M: Standard Specification for Steel Bars, Carbon and Alloy, Hot-Wrought
- API Spec 6A: Specification for Wellhead and Tree Equipment
- API Spec 7-1: Specification for Rotary Drill Stem Elements
- NACE MR0175 / ISO 15156: Materials for use in H₂S-containing environments (80ksi variant)
- AMS 2750: Pyrometry – heat treatment furnace requirements
- AMS 2301: Steel Cleanliness, Aircraft Quality
Available Sizes & Delivery
ShunFu Metal offers highly flexible supply capabilities for AISI 4140 Modified steel. We supply hot-rolled and forged round bars from 1″ to 12″ (25.4mm–304.8mm), alongside custom flat bars and pre-drilled hollow bars. Our manufacturing leverages high forging ratios for optimal grain structure, API-calibrated heat treatment furnaces, and advanced machining including BTA deep-hole drilling, CNC lathes, and long-distance gunhole drilling.
Delivery & MOQ
- Ready Stock: Common sizes available for immediate shipment (MOQ: 1 piece, ~7 days delivery).
- Custom Forged/Rolled: Tailored dimensions with a standard MOQ of 3 tons (~30 days delivery).
- Small Batch Melting: Our specialized 3–5 ton induction furnaces accommodate niche custom chemistry requirements.
- Large Volume Orders: Processed via our 30–60T EAF for rapid, large-scale fulfillment.
Chemical Composition
ShunFu Metal verifies every melt through rigorous in-house spectrometry before pouring, ensuring all elemental fractions strictly comply with your target specifications and our enhanced cleanliness standards. We can also micro-adjust the composition based on your specific performance requirements.
| Element | Minimum % | Maximum % |
|---|---|---|
| Carbon (C) | 0.40 | 0.43 |
| Silicon (Si) | 0.20 | 0.35 |
| Manganese (Mn) | 0.75 | 1.10 |
| Phosphorus (P) | – | 0.015 |
| Sulfur (S) | – | 0.020 |
| Chromium (Cr) | 0.80 | 1.20 |
| Molybdenum (Mo) | 0.25 | 0.35 |
| Nickel (Ni) | – | 0.25 |
| Aluminum (Al) | 0.015 | 0.030 |
The bold values in the original specification highlight the tighter chemistry controls and enhanced alloy content that differentiate 4140 Modified from standard 4140 steel.
Melting & Processing
ShunFu Metal offers flexible melting routes tailored to your needs:
- Standard: EAF + LF + VD (Extended Vacuum Degassing)
- Higher Purity: ESR or PESR
- Maximum Cleanliness: VIM + VAR
Customers can consult our metallurgical engineers to select the optimal melting process to achieve the exact cleanliness and fatigue life required for their application.
Mechanical Properties
ShunFu Metal issues comprehensive mechanical property test reports from accredited laboratories prior to delivery, with all yield, tensile, and impact data fully traceable to the specific heat and batch number.
80ksi Variant (NACE MR0175 Compliant)
| Property | Minimum | Maximum |
|---|---|---|
| 0.2% Yield Strength | 80 ksi (552 MPa) | – |
| Ultimate Tensile Strength | 100 ksi (690 MPa) | – |
| Elongation | 20% | – |
| Reduction of Area | 45% | – |
| Hardness | 18 HRC / 217 HBW | 22 HRC / 237 HBW |
| Charpy V-Notch @ 23°C | 80 J (Average) | – |
| Charpy V-Notch @ -32°C | 55 J (Average) | 40 J (Min Single) |
110ksi Variant
| Property | Minimum | Maximum |
|---|---|---|
| 0.2% Yield Strength | 110 ksi (758 MPa) | – |
| Ultimate Tensile Strength | 135 ksi (931 MPa) | – |
| Elongation | 13% | – |
| Reduction of Area | 40% | – |
| Hardness | 30 HRC / 285 HBW | 36 HRC / 341 HBW |
| Charpy V-Notch @ 0°C | 30 J (Average) | 22 J (Min Single) |
| Charpy V-Notch @ -20°C | 27 J (Average) | 20 J (Min Single) |
125ksi Variant
| Property | Minimum | Maximum |
|---|---|---|
| 0.2% Yield Strength | 125 ksi (862 MPa) | – |
| Ultimate Tensile Strength | 135 ksi (931 MPa) | – |
| Elongation | 13% | – |
| Reduction of Area | 40% | – |
| Hardness | 32 HRC / 301 HBW | 38 HRC / 352 HBW |
| Charpy V-Notch @ 0°C | 25 J (Average) | 20 J (Min Single) |
Heat Treatment
| Process | Temperature Range | Holding Time | Cooling Method |
|---|---|---|---|
| Austenitizing | 840°C – 870°C | 1 hour per inch of section | Liquid Quench (Polymer/Oil) |
| Tempering | 540°C – 680°C | 1 hour per inch of section | Air Cool |
| Stress Relieving | 500°C – 550°C | 1 – 2 hours | Air Cool / Furnace Cool |
ShunFu Metal’s heat treatment facility utilizes furnaces that are regularly surveyed and calibrated in strict compliance with API and AMS 2750 standards. This guarantees exceptional temperature uniformity and process repeatability, ensuring every batch of AISI 4140 Modified steel achieves the precise through-section hardness and impact toughness required for critical downhole environments.
Surface Finish & Machining
Leveraging our comprehensive in-house machining center, ShunFu Metal delivers AISI 4140 Modified steel in various precision finishes. We offer turning, grinding, and CNC milling to achieve tight dimensional tolerances and surface roughness down to Ra 0.8μm. For tubular oilfield components, our specialized BTA boring and long-distance gunhole drilling ensure perfect concentricity. We also provide roller burnishing and shot peening to enhance surface fatigue resistance. By integrating these precision machining capabilities directly at the factory level, we eliminate third-party processing delays and guarantee exact fitment for your final components.
Quality Assurance & Inspection
ShunFu Metal’s API Q1 and ISO 9001 certified quality system governs every production phase. We conduct 100% Ultrasonic Testing (UT) per ASTM A388 (meeting API 6A PSL 3&4), alongside rigorous chemical, dimensional, and metallographic evaluations (verifying ASTM 5 grain size or finer). Crucially, we perform four-quadrant hardness testing to verify uniform through-thickness strength in heavy-walled components.
We provide EN 10204 3.1 certificates standard, with 3.2 certification available upon request. We also routinely coordinate with SGS, TÜV, and other third-party inspectors, ensuring our oilfield clients receive materials with zero defects.
Packing & Shipping
With over a decade of experience exporting to 50+ countries, ShunFu Metal ensures secure transit. Black-surface bars are tightly wire-bundled, while bright/machined components receive multi-layer protective wrapping and heavy anti-rust oil coating. We strictly accommodate all destination port documentation and custom seaworthy packaging requirements.
Frequently Asked Questions
Can ShunFu Metal supply AISI 4140 Modified steel to API 6A and NACE MR0175 specifications?
Yes. As an API Q1 certified manufacturer, ShunFu Metal strictly controls the chemical composition (specifically limiting sulfur to ≤ 0.020% and phosphorus to ≤ 0.015%) and utilizes our AMS 2750 calibrated heat treatment furnaces to ensure our 80ksi variant fully complies with NACE MR0175/ISO 15156 for sour service environments.
What is the minimum order quantity (MOQ) for custom-machined 4140 Modified drill collars?
For standard sizes available in our ready stock, the MOQ is just 1 piece. For custom-forged or CNC-machined components requiring specific BTA deep-hole drilling, our typical MOQ is 3 tons, though we can easily accommodate smaller trial batches using our 3–5 ton induction melting furnaces.
How does ShunFu Metal guarantee the internal soundness of heavy-walled components?
Every piece of AISI 4140 Modified steel undergoes 100% Ultrasonic Testing (UT) in our facility according to ASTM A388, evaluated against stringent API 6A PSL 3&4 acceptance criteria. We also perform four-quadrant hardness testing to verify uniform through-section properties, ensuring the material will not fail under high-stress drilling conditions.
What sizes and forms of AISI 4140 Modified steel can ShunFu Metal deliver?
We supply hot-rolled and forged round bars from 1″ to 12″ (25.4–304.8mm), plus custom flat bars and pre-drilled hollow bars. Machined components such as tool joints, drill collars, and top drive parts are also available directly from our factory. Contact us to discuss your exact dimensional and finishing requirements.
