Project Description
4145H MOD Alloy Steel Hollow Bars
4145H MOD is a premium chromium-molybdenum alloy steel engineered for exceptional hardenability, toughness, and resistance to fatigue. Modified with higher alloy content than standard 4145, it delivers superior mechanical properties for severe downhole environments.
As a dedicated manufacturer for the global oil & gas and mining sectors, Hunan ShunFu Metal Material Co., Ltd. specializes in producing this critical grade. Backed by our API Q1 and ISO 9001 certifications, we supply 4145H MOD pre-drilled hollow bars to the world’s top 10 oilfield service companies. Our extensive export experience ensures that every heat lot delivers the uniform chemistry and material integrity your projects demand.
Equivalent Grades
| Standard / Region | Grade Designation |
|---|---|
| API (US) | 4145H MOD |
| UNS | G41450 (Modified) |
| DIN / EN | 42CrMo4 (Modified) |
Applications
- Drill Collar Blanks: Supplied by ShunFu Metal as precision-machined pre-drilled hollow bars for drill collars, ready for final threading and immediate deployment by the customer.
- MWD / LWD Housings: Delivered as deep-hole bored tubes with exceptionally tight ID tolerances, utilizing ShunFu Metal's in-house BTA boring and honing capabilities. We also supply non-magnetic steel grades for demanding MWD applications.
- Downhole Motor Components: Supplied as forged and quenched & tempered rounds, heat-treated in ShunFu Metal’s API-calibrated furnaces for optimal yield strength and fatigue resistance. Explore our hollow bar capabilities.
- Valve Body Forgings: Provided as custom forged blocks or thick-walled hollows, ensuring high structural integrity for high-pressure fluid control, fully tested by ShunFu Metal's QA team.
Specifications & Standards
ShunFu Metal strictly organizes production according to these international standards and can issue fully traceable material test certificates corresponding to your required specification.
- API Spec 7-1 (Rotary Drill Stem Elements)
- API 5CT (Casing and Tubing – related applications)
- ASTM A29 / ASTM A322 (Standard Specification for Alloy Steel Bars)
Available Sizes & Delivery
ShunFu Metal offers exceptional flexibility in supplying 4145H MOD. Our size range covers ODs from 3.00" to 11.00" (76.2–279.4 mm) and IDs from 1.00" to 4.00" (25.4–101.6 mm), in lengths up to 50 feet (15 meters). We utilize high-ratio forging for superior grain structure, combined with advanced BTA deep-hole drilling and CNC machining.
| Parameter | Value |
|---|---|
| Outside Diameter (OD) | 3.00 – 11.00 inches (76.2 – 279.4 mm) |
| Inside Diameter (ID) | 1.00 – 4.00 inches (25.4 – 101.6 mm) |
| Maximum Length | Up to 50 ft (15 m) |
| Common Sizes (Stock) | Ready stock in Shanghai – approx. 7-day global shipment; single-piece orders accepted |
| Custom Forgings / Rolled Bars | MOQ 3 tons – approx. 30-day lead time |
| Small-Batch Micro-Alloy Melts | 3–5 ton induction furnaces available |
| Large-Scale Projects | 30–60 ton EAF capabilities for rapid turnaround |
Need a specialized micro-alloy? ShunFu Metal’s flexible melting routes accommodate both small trials and full production runs.
Chemical Composition
ShunFu Metal verifies every melt through rigorous in-house spectrometry, ensuring all elemental contents strictly meet API 7 specifications. We can also micro-alloy and fine-tune the chemistry to match your specific performance demands.
| Element | Content (%) |
|---|---|
| Carbon (C) | 0.42 – 0.49 |
| Manganese (Mn) | 0.65 – 1.10 |
| Silicon (Si) | 0.15 – 0.35 |
| Chromium (Cr) | 0.75 – 1.20 |
| Molybdenum (Mo) | 0.15 – 0.35 |
| Phosphorus (P) | 0.025 max |
| Sulfur (S) | 0.025 max |
Melting & Processing
ShunFu Metal offers tailored melting routes. Our standard is EAF + LF + VD for excellent purity. For stricter demands, we provide ESR or PESR. Customers can negotiate the optimal melting strategy with ShunFu Metal to perfectly balance cost and downhole performance.
Mechanical Properties
ShunFu Metal issues comprehensive mechanical testing reports from our accredited laboratory prior to delivery, with all data fully traceable to the specific heat and batch number.
| Property | Value |
|---|---|
| Tensile Strength (min) | 135,000 psi (930 MPa) |
| Yield Strength (min) | 110,000 psi (760 MPa) |
| Charpy V-Notch Impact (Longitudinal, min) | 40 ft-lbs (54 J) |
| Charpy V-Notch Impact (Transverse, min) | 20 ft-lbs (27 J) |
| Hardness | 285 – 341 BHN |
Heat Treatment
ShunFu Metal’s heat treatment facility features furnaces strictly calibrated to API standards. This guarantees exceptional temperature uniformity and process repeatability, ensuring every 4145H MOD hollow bar develops the fine, fully tempered martensite/sorbite structure required for maximum sulfide stress corrosion cracking resistance.
| Process | Temperature / Details | Cooling Method |
|---|---|---|
| Austenitizing | 840°C – 870°C (hold time based on section thickness) | Water or Polymer Quench |
| Tempering | 540°C – 680°C (adjusted to target hardness) | Air Cool |
Surface Finish & Machining
ShunFu Metal delivers factory-direct precision. For 4145H MOD hollow bars, our in-house capabilities include BTA deep-hole boring, pull boring, skiving, and honing for flawless IDs, alongside OD turning and CNC milling. We achieve exacting surface roughness (Ra) values and tight dimensional tolerances over lengths up to 50 feet.
By integrating these advanced machining and roller burnishing processes under one roof, ShunFu Metal eliminates third-party delays and guarantees the precise surface finish your downhole tools demand. Learn more about our hollow bar and precision boring services.
Quality Assurance & Inspection
Quality is engineered into every step at ShunFu Metal. Our API Q1 and ISO 9001 certified protocols dictate rigorous testing: full-length ultrasonic testing (UT), precise dimensional checks, and metallographic analysis. We conduct strict 4-quadrant hardness testing to guarantee uniform strength across the bar's cross-section, alongside comprehensive chemical and mechanical evaluations.
This uncompromising QA process means your 4145H MOD products arrive defect-free. We provide EN 10204 3.1 certificates as standard, with 3.2 certification and third-party inspections (SGS, TÜV) available upon request. About ShunFu Metal’s quality commitments.
Packing & Shipping
Black-forged products are securely wire-tied to prevent transit damage. For precision-machined hollow bars, ShunFu Metal applies premium anti-rust oil and multi-layer protective packaging. Leveraging our experience exporting to over 50 countries, we ensure flawless maritime transit and full compliance with your destination's specific documentation requirements.
Frequently Asked Questions
Can ShunFu Metal supply 4145H MOD hollow bars to API specifications?
Yes, ShunFu Metal manufactures, heat-treats, and tests all 4145H MOD products in strict accordance with API Spec 7-1, fully backed by our API Q1 certified quality management system.
What is the minimum order quantity for 4145H MOD pre-drilled bars?
Thanks to our strategic inventory in Shanghai, ShunFu Metal can supply industry-common sizes from ready stock with no strict MOQ. For custom sizes or specific forgings, our MOQ is typically 3 tons.
What deep hole drilling capabilities does ShunFu Metal offer?
ShunFu Metal operates advanced BTA boring and trepanning equipment in-house. We can drill or trepan IDs from 1.00" to 4.00" in bar lengths up to 50 feet (15 meters), ensuring a simplified and cost-effective supply chain for our clients.
What heat treatment is applied to 4145H MOD?
Austenitizing at 840°C–870°C followed by water or polymer quench, then tempering at 540°C–680°C adjusted to target hardness. This develops the fine tempered martensite/sorbite structure required for maximum sulfide stress cracking resistance.
What material certificates are provided with shipments?
We issue EN 10204 3.1 certificates as standard, with 3.2 certification and third-party inspections (SGS, TÜV) available upon request. All testing reports are fully traceable to the heat and batch number.
