Project Description
Introduction to 4330V Modified Alloy Steel
4330V modified alloy steel is a vacuum-degassed, high-strength low-alloy grade engineered to withstand extreme torsional loads, bending stresses, and high-cycle fatigue. The strategic vanadium addition refines austenite grain boundaries during thermal processing, delivering superior toughness critical for raise bore drill rods and heavy-duty drilling components.
At Hunan ShunFu Metal Material Co., Ltd., we produce 4330V directly from our integrated melt shop and forging lines. We supply API Q1 and ISO 9001-certified material to top-tier global oilfield service companies and mining contractors. Our controlled vacuum degassing and precision thermal processing ensure every bar meets rigorous downhole demands.
Equivalent Grades
| Standard / System | Equivalent Designation |
|---|---|
| AISI / SAE | 4330V / 4330 Modified |
| DIN / EN | 1.6511 (Modified) / 30CrNiMo8V |
| GB (China) | 30CrNiMo8V |
| JIS (Japan) | SNCM431 (Modified) |
Primary Applications
- Raise Bore Drill Rods: Supplied as precision-machined hollow bars or solid rounds, heat-treated and BTA deep-hole drilled to exact OD/ID tolerances for immediate threading.
- Drill Collar Blanks & Stabilizer Bodies: Delivered as high-forging-ratio round bars for drill collar manufacturing, normalized and quenched/tempered in API-calibrated furnaces before CNC rough machining.
- Heavy-Wall Mining Shafts & Rock Drill Steels: Provided as forged round or flat bars with controlled grain flow, ready for downstream hard-facing and fatigue-critical service.
- Downhole Tool Joints & Sub Assemblies: Supplied as custom-cut forged billets or pre-machined blanks, with in-house UT and four-quadrant hardness verification ensuring defect-free performance.
- High-Torque Drill Pipe Tool Joints: Manufactured from vacuum-degassed 4330V rounds for drill pipe assemblies, heat-treated to matched strength levels and delivered with full traceability for API-spec welding.
Specifications & Standards
ShunFu Metal strictly manufactures 4330V in full compliance with international metallurgical standards. Upon request, we issue corresponding standard-specific Mill Test Certificates with complete heat-to-finished-product traceability.
Available Sizes & Delivery
ShunFu Metal supplies 4330V in hot-rolled and open-die forged round bars (Ø50–Ø600 mm) and flat bars (thickness 50–400 mm, width up to 800 mm). Our hydraulic forging presses achieve reduction ratios exceeding 4:1, closing internal porosity and refining grain structure for maximum fatigue life.
All bars undergo thermal processing in our API-calibrated heat treatment furnaces, followed by precision machining on CNC lathes and BTA deep-hole drilling lines. For standard sizes, we maintain ready stock with single-piece MOQ and ~7-day dispatch. Custom forged orders require a 3-ton MOQ with ~30-day lead times.
Chemical Composition
ShunFu Metal verifies every heat through in-house spectrometry before tapping, ensuring strict adherence to specified ranges. We can also fine-tune micro-alloying elements to match your target hardenability or impact requirements.
| Element | C | Mn | Si | Cr | Ni | Mo | V | P ≤ | S ≤ |
|---|---|---|---|---|---|---|---|---|---|
| 4330V | 0.28–0.33 | 0.75–1.00 | 0.15–0.35 | 0.75–1.05 | 1.65–2.00 | 0.35–0.50 | 0.05–0.10 | 0.025 | 0.025 |
Melting & Processing
ShunFu Metal produces 4330V via EAF + LF + VD as standard, ensuring hydrogen levels remain below 2 ppm to prevent flaking. For critical downhole applications, we offer ESR or PESR remelting. For highest purity demands, VIM + VAR routes are available.
Mechanical Properties
| Condition | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Charpy V-Notch (J, RT) |
|---|---|---|---|---|
| Q&T (540–620°C Temper) | 960–1100 | 860–1000 | ≥14 | ≥50 |
ShunFu Metal provides accredited laboratory mechanical test reports with every shipment. All tensile, impact, and hardness data are fully traceable to the specific heat number and production batch.
Heat Treatment Protocols
| Process | Temperature Range | Holding Time | Cooling Medium |
|---|---|---|---|
| Normalizing | 900–930°C | Section-dependent | Still Air |
| Austenitizing | 845–870°C | Section-dependent | Oil / Polymer Quench |
| Tempering | 540–620°C | 2–4 hours (multiple cycles) | Still Air |
ShunFu Metal’s heat treatment furnaces are calibrated and audited strictly according to API standards, guaranteeing exceptional temperature uniformity. This controlled thermal environment ensures 4330V consistently achieves a uniform tempered martensitic structure, eliminating soft spots and maximizing through-thickness toughness.
Surface Finish & Machining
ShunFu Metal delivers 4330V bars in black, turned, ground, or fully CNC-machined conditions. Our turning and milling lines achieve Ra 1.6–3.2 µm with h9/h7 diameter tolerances, while precision grinding delivers Ra ≤0.8 µm for sealing surfaces.
For hollow drill rod configurations, our BTA deep-hole drilling systems produce straight, concentric bores with tight ID tolerances. By integrating machining directly into our production flow, ShunFu Metal eliminates secondary handling and reduces your total lead time.
Quality Assurance & Inspection
ShunFu Metal enforces a rigorous API Q1 and ISO 9001-compliant quality system across every 4330V production stage. Each bar undergoes ultrasonic testing (UT) to stringent flat-bottom hole acceptance criteria, four-quadrant hardness mapping, and metallographic grain size verification.
We issue EN 10204 3.1 certificates as standard, with 3.2 certification available upon request. Third-party inspections by SGS, TÜV, or client-nominated agencies are fully supported and coordinated at our facility.
Packing & Shipping
Black-finish bars are securely bundled with high-tensile steel wire to prevent transit damage. Precision-machined or ground bars receive multi-layer protective wrapping and end caps to preserve surface finish and dimensional accuracy.
All materials are coated with industrial-grade anti-rust oil for ocean freight protection. With exports to over 50 countries, ShunFu Metal seamlessly complies with destination-specific packaging, marking, and customs documentation requirements.
Frequently Asked Questions
Can ShunFu Metal supply 4330V round bars to API or ASTM specifications?
Yes. We manufacture 4330V in strict accordance with ASTM A29/A322 and API Spec 7-1 material requirements. Every heat is vacuum-degassed, spectrometry-verified, and supplied with full EN 10204 3.1 certification and traceable mechanical test reports.
What is the minimum order quantity for 4330V drill rod stock?
For standard diameters held in ready stock, we accept single-piece orders with dispatch within 7 days. Custom forged or rolled sizes require a 3-ton MOQ. For specialized chemistry modifications, our induction furnace accommodates melts as low as 3–5 tons.
How does ShunFu Metal ensure fatigue resistance in large-diameter 4330V bars?
Fatigue performance is secured through our controlled EAF+LF+VD steelmaking (hydrogen <2 ppm), minimum 4:1 forging reduction to close porosity, and API-calibrated quench & temper cycles. We also perform mandatory UT and inclusion rating per ASTM E45 to eliminate crack-initiation sites before shipment.
Can you supply pre-machined hollow bars for raise bore drill rods?
Absolutely. ShunFu Metal’s integrated BTA deep-hole drilling and CNC machining lines produce precision hollow bars with tight OD/ID concentricity and specified surface roughness. We deliver them heat-treated, inspected, and ready for your threading and hard-facing operations.
Ready to Upgrade Your Drill String Components?
Contact our metallurgical engineering team today for technical datasheets, custom forging capabilities, or competitive pricing on 4330V modified alloy steel.