Project Description
AISI 4140 Hollow Bar & Solid Bar Overview
AISI 4140 is a premium chromium-molybdenum alloy steel renowned for its exceptional yield strength, fatigue resistance, and through-hardening capabilities. The precise addition of chromium and molybdenum enhances high-temperature strength and prevents temper embrittlement, making this grade a cornerstone material across the oilfield equipment supply chain.
As an API Q1 and ISO 9001 certified manufacturer, ShunFu Metal specializes in producing high-performance 4140 hollow bar and solid bar products specifically for the demanding oil, gas, and mining sectors. With extensive export experience to over 50 countries and a proven track record supplying the world's top 10 oilfield service companies, we possess the technical authority and manufacturing capability to deliver this versatile grade for your most critical applications.
From drill collar blanks requiring exact concentricity to casing and tubing accessories demanding sour service compliance, our metallurgical and machining expertise ensures every bar meets the specification your project demands.
Equivalent Grades
| US / ASTM | UNS | DIN / EN | JIS | GB |
|---|---|---|---|---|
| AISI 4140 | G41400 | 1.7225 / 42CrMo4 | SCM440 | 42CrMoA |
Applications
- Drill Collar Blanks (Oil & Gas / Drilling): Supplied by ShunFu Metal as precision-machined 4140 hollow bar, utilizing our advanced BTA deep hole drilling and CNC machining to ensure exact concentricity and straightness for directional drilling operations.
- Valve Bodies & Bonnets (Oil & Gas): Provided as heavy forged round steel, fully quenched and tempered in our AMS 2750 compliant furnaces to meet NACE MR0175/ISO 15156 standards for sour service environments.
- Blowout Preventer (BOP) Components: Delivered as heavy-wall 4140 hollow bar or custom forgings, undergoing 100% ultrasonic testing by our in-house quality team to guarantee high-pressure containment integrity.
- Rock Drill Steel & Tool Joints (Mining): Supplied as hot-rolled or forged bars, complete with customized heat treatment and precise turning from our factory to withstand severe impact and wear in hard-rock mining.
Specifications & Standards
ShunFu Metal strictly organizes production in accordance with the following international standards and can issue corresponding material test certificates based on your specific project requirements.
- ASTM: ASTM A29 / A29M, ASTM A322, ASTM A388
- API: API 6A
- NACE: NACE MR0175 / ISO 15156
- AMS: AMS 2301, AMS 2750
- DIN / EN: DIN 1.7225 / EN 10083-3 (42CrMo4)
- JIS: JIS G4105 (SCM440)
- GB: GB/T 3077 (42CrMoA)
Available Sizes & Delivery Options
ShunFu Metal offers flexible supply of AISI 4140, including hot-rolled bars (1″ to 10″), forged bars, and precision 4140 hollow bar. Our heavy forging capabilities ensure a minimum 4:1 reduction ratio for optimal grain flow, supported by API-calibrated heat treatment and BTA deep hole drilling.
- Ready Stock: Common sizes available for immediate dispatch, MOQ of 1 piece, approximately 7 days delivery.
- Custom Forgings / Rolled Bars: MOQ typically 3 tons, approximately 30 days delivery.
- Small Batch Special Melts: In-house small induction furnaces allow custom melts from 3–5 tons.
- Large Volume Orders: 30–60 ton EAF capacity ensures rapid delivery.
Chemical Composition
ShunFu Metal rigorously verifies the chemistry of every heat through in-house spectrometry before pouring, ensuring that all alloying elements strictly meet specification and can be micro-adjusted to suit your specific mechanical performance needs.
| Element | Minimum % | Maximum % |
|---|---|---|
| Carbon (C) | 0.38 | 0.43 |
| Silicon (Si) | 0.15 | 0.35 |
| Manganese (Mn) | 0.75 | 1.00 |
| Phosphorus (P) | – | 0.035 |
| Sulfur (S) | – | 0.040 |
| Chromium (Cr) | 0.80 | 1.10 |
| Molybdenum (Mo) | 0.15 | 0.25 |
| Nickel (Ni) | – | 0.25 |
| Aluminum (Al) | 0.015 | 0.030 |
Melting & Processing Routes
We offer standard EAF + LF + VD melting as the baseline refining route. For applications requiring superior cleanliness—such as CRA piping components or critical subsea equipment—ESR (Electroslag Remelting), PESR, or VIM + VAR (Vacuum Induction Melting + Vacuum Arc Remelting) are available. Customers can consult ShunFu Metal to customize the ideal metallurgical route for your specific service conditions.
Mechanical Properties
Prior to delivery, ShunFu Metal provides comprehensive mechanical property test reports from our approved laboratories, with all data fully traceable to the specific heat and batch numbers.
| Variant | 0.2% Yield Strength | Ultimate Tensile Strength | Elongation | Hardness | Impact (Charpy V-Notch @ 23°C) |
|---|---|---|---|---|---|
| 80ksi (NACE) | ≥ 80 ksi (552 MPa) | ≥ 100 ksi (690 MPa) | ≥ 20% | 18–22 HRC (217–237 HBW) | 80 J (59 ft-lb) avg |
| 110ksi (High-Strength) | ≥ 110 ksi (758 MPa) | ≥ 125 ksi (862 MPa) | ≥ 13% | 30–36 HRC (285–341 HBW) | 60 J (44 ft-lb) avg |
Heat Treatment Parameters
ShunFu Metal's heat treatment furnaces are strictly calibrated and regularly surveyed in accordance with AMS 2750 and API standards. This guarantees exceptional temperature uniformity and process repeatability, ensuring every batch of AISI 4140 achieves the precise hardenability, strength, and toughness required for your critical applications.
| Process | Temperature Range | Cooling Method |
|---|---|---|
| Austenitizing | 840°C – 870°C (1545°F – 1600°F) | Liquid Quench (Oil or Polymer) |
| Tempering | 540°C – 680°C (1000°F – 1255°F) | Air Cool |
| Stress Relieving | 500°C – 550°C (930°F – 1020°F) | Furnace Cool |
Surface Finish & Machining Capabilities
Leveraging our in-house CNC lathes, milling centers, and BTA deep hole drilling equipment, ShunFu Metal provides precision-machined 4140 hollow bar profiles. We offer peeled, turned, and ground finishes achieving precise Ra roughness values and tight dimensional tolerances, delivering factory-direct, ready-to-use components that reduce your downstream machining costs.
Quality Assurance & Inspection
As an API Q1 and ISO 9001 certified manufacturer, ShunFu Metal conducts 100% UT per ASTM A388, four-quadrant hardness testing, metallography, and comprehensive dimensional checks. This multi-layered inspection protocol guarantees uncompromising AISI 4140 integrity for every order. We issue EN 10204 Type 3.1 certificates as standard and welcome third-party inspections from SGS or TÜV at any stage of production.
Packing & Shipping
Having exported to over 50 countries, ShunFu Metal expertly packs every order to destination requirements. Black surface materials are securely wire-bundled, while precision-machined 4140 hollow bars receive anti-rust oil coating and multi-layer protective wrapping to preserve dimensional accuracy throughout global ocean transit.
Frequently Asked Questions
Can ShunFu Metal supply AISI 4140 hollow bar to API 6A and NACE specifications?
Yes. Our fully calibrated heat treatment facilities allow us to produce the 80ksi variant of AISI 4140, strictly conforming to NACE MR0175/ISO 15156 for sour service and API 6A standards for wellhead and tree equipment.
What is the minimum order quantity for custom 4140 hollow bar or forgings?
For custom forged or rolled AISI 4140, our MOQ is typically 3 tons. However, ShunFu Metal maintains ready stock for common sizes allowing 1-piece orders, and we utilize small induction furnaces to accommodate special 3–5 ton melts for highly customized requirements.
How does ShunFu Metal ensure the internal soundness of heavy-wall 4140 products?
Every piece of AISI 4140 steel undergoes 100% ultrasonic testing (UT) by our in-house inspection team according to ASTM A388 and API 6A PSL 3 & 4 acceptance criteria, ensuring the complete absence of internal defects before leaving our factory.
What equivalent grades are available, and can ShunFu Metal certify to my local standard?
AISI 4140 corresponds to UNS G41400, DIN 1.7225 / 42CrMo4 (EN 10083-3), JIS SCM440 (JIS G4105), and GB 42CrMoA (GB/T 3077). We issue EN 10204 3.1 certificates to any of these standards based on your project specification.
What heat treatment capabilities support sour service and high-strength variants?
Our AMS 2750 compliant furnaces perform precisely controlled austenitizing, liquid quenching, and tempering cycles. For the NACE 80ksi variant, we temper at the upper range (above 620°C) to achieve hardness below 22 HRC, while the 110ksi high-strength variant uses lower tempering temperatures to retain strength above 30 HRC. Full process records are traceable by heat number.
