Project Description
Inconel X-750 (UNS N07750 / W. Nr. 2.4669 / NiCr15Fe7TiAl) is a precipitation-hardenable nickel-chromium alloy strengthened by additions of aluminum (0.40–1.00 %) and titanium (2.25–2.75 %), which combine to form coherent γ’ (gamma prime) precipitates within the austenitic matrix. This age-hardening mechanism delivers very high tensile and yield strength — up to 1,380 MPa tensile in spring temper — while retaining excellent relaxation resistance below 540 °C and oxidation resistance up to 980 °C. In the oil and gas sector, Inconel X-750 bar is the go-to material for high-stress, high-temperature components that demand dimensional stability over long service intervals: downhole lock mandrels, wellhead fasteners, Belleville springs in safety valves, retaining rings in compressors, and anti-vibration clips in high-pressure process pipework. SHUNFU METAL supplies N07750 bar from VIM-cast, homogenized heats, hot-forged or hot-rolled to bar, and heat-treated to the customer-specified aging condition — delivering EN 10204 3.1 / 3.2 MTR with chemistry, mechanical test, and hardness survey on every lot.
Inconel X-750 / N07750 — Introduction
Alloy X-750 occupies a unique niche among nickel superalloys: it is the only INCONEL® grade specifically optimized for spring and fastener applications at temperatures where austenitic stainless steels lose relaxation resistance. The precipitation-hardening response is controlled by the Al + Ti atomic ratio; at Ni₃(Al,Ti) composition, the γ’ precipitates are fully coherent with the matrix, providing a combination of strength, ductility, and fatigue resistance unavailable in solid-solution alloys. The alloy’s composition also inherits the chloride-SCC resistance of Alloy 600, making it suitable for sour and chloride environments encountered downhole and in offshore topsides.
SHUNFU METAL offers three standard aging routes for N07750 bar: Route A (single age 704 °C / 20 h — maximum room-temperature strength), Route B (885 °C / 24 h + 704 °C / 20 h — balanced strength and relaxation resistance to 540 °C), and Route C (982 °C / 1 h + 843 °C / 24 h + 704 °C / 20 h — maximum creep and rupture strength to 816 °C). All aged bars undergo hardness traverse, tensile test, and optional stress-rupture test per ASTM E139 for critical downhole applications.
Equivalent Grades & Applicable Standards
| Standard Body | Designation / Grade | Specification / Form |
|---|---|---|
| ASTM | N07750 | B637 (bar, rod & forgings), B670 (plate, sheet & strip) |
| ASME | N07750 | SB-637 (bar & forgings) |
| AMS | — | AMS 5667 (bar, rod & forgings — Condition A), AMS 5668 (bar — Condition B), AMS 5669 (bar — Condition C), AMS 5542 (sheet/strip), AMS 5598 (sheet/strip — aged), AMS 5698/5699 (spring wire) |
| EN / DIN | NiCr15Fe7TiAl / 2.4669 | DIN 17744 (composition), DIN 17752 (bar), EN ISO 9723 (bar & rod) |
| BS | NA 55 | BS 3076 (bar & rod) |
| AFNOR | NC15TNbA | NF A-05-054 |
| JIS | NCF 750 | JIS G4902 (bar) |
| Chinese GB / GH | GH4145 / GH145 | GB/T 14992, GB/T 15062 (bar) |
| ISO | NiCr15Fe7TiAl | ISO 9723 (bar & rod) |
Oil & Gas Applications — Inconel X-750 Bar Components
Precision-machined lock mandrels and setting sleeves in packer assemblies where sustained load retention at 150–250 °C is critical.
High-strength studs, nuts, and bolting for wellhead connectors and subsea tree flanges per ASTM B637 and ISO 13628 requirements.
Disc springs and conical washers in SSV and wellhead choke bodies requiring consistent spring rate after thermal cycling.
Valve plate retaining rings and spring seats in reciprocating and centrifugal gas compressors handling sour or acid gas streams.
Spring-loaded clamps and clip assemblies securing high-pressure tubing bundles on offshore topsides in corrosive, high-vibration service.
Gun body bars, detonator retainers, and shaped-charge positioning mandrels for downhole perforating tools in HPHT wells.
Turbine casing bolts, blade retaining pins, and sealing ring fasteners in gas turbine compressor drivers on pipeline and offshore platforms.
Sliding sleeve bodies, mandrel blanks, and flow-control insert bars for ICD completions in high-temperature sour reservoirs.
Supply Forms & Size Range — Inconel X-750 Bar
| Form | Size Range | Applicable Standard | Condition |
|---|---|---|---|
| Hot-Rolled Round Bar | Ø 6 mm – Ø 200 mm | ASTM B637 | Annealed or aged (A/B/C) |
| Hot-Rolled Flat Bar | Thickness 6–100 mm × Width 20–350 mm | ASTM B637 | Annealed or aged |
| Cold-Drawn Round Bar | Ø 3 mm – Ø 80 mm | ASTM B637 / AMS 5667 | Stress-equalized + aged |
| Forged Round Bar | Ø 80 mm – Ø 700 mm | ASTM B637 / AMS 5667–5669 | Forged + annealed + aged |
| Forged Flat / Block | Thickness 50–350 mm × Width up to 1,000 mm | ASTM B637 / EN ISO 9723 | Forged + annealed + aged |
Standard lengths: 1,000–6,000 mm; cut-to-length available. SHUNFU METAL stocks annealed and Condition A–aged bars in common diameters (Ø 12–Ø 120 mm) for prompt delivery. All finished bars can be supplied as-rolled/black, turned (peeled), or precision-ground to h9/h11. Heat treatment certificates with time-temperature charts are provided as standard for aged product.
Chemical Composition — ASTM B637 / N07750
| Element | Ni + Co | Cr | Fe | Ti | Nb + Ta | Al | C | Mn | Si | S | Cu |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Content (%) | ≥ 70.0 | 14.0–17.0 | 5.0–9.0 | 2.25–2.75 | 0.70–1.20 | 0.40–1.00 | ≤ 0.08 | ≤ 0.30 | ≤ 0.50 | ≤ 0.01 | ≤ 0.50 |
Bold elements (Ti, Nb+Ta, Al) are the γ’ precipitation-hardening agents. SHUNFU METAL verifies Ti and Al by ICP-OES on every heat. Composition per ASTM B637 / AMS 5667 / UNS N07750. Full 12-element MTR provided with every shipment.
Mechanical Properties — Inconel X-750 Bar by Heat Treatment Condition
| Condition | Tensile Strength Rm (MPa) |
Yield Strength Rp0.2 (MPa) |
Elongation A₅ (%) |
Hardness HB |
|---|---|---|---|---|
| Condition A — Single Age 704 °C / 20 h, air cool |
1,170–1,420 | 790–980 | 15–25 | 313–400 |
| Condition B — Stress Equalized + Age 885 °C / 24 h, AC + 704 °C / 20 h, AC |
1,103–1,359 | 724–1,034 | 20–30 | 300–390 |
| Condition C — Full Solution + Double Age 982 °C / AC + 843 °C / 24 h, AC + 704 °C / 20 h, AC |
1,103–1,296 | 690–965 | 20–30 | 302–363 |
| Annealed (pre-aging baseline) Solution treated, no aging |
827–1,124 | 379–690 | 30–45 | 200–280 |
Test temperature: 20 °C. Standards: ASTM B637 / AMS 5667 (Condition A), AMS 5668 (Condition B), AMS 5669 (Condition C). Density: 8.28 g/cm³. Melting range: 1,393–1,427 °C. SHUNFU METAL performs full tensile and hardness test on each aged lot; stress-rupture data at 650 °C / 690 MPa is available on request for downhole packer and lock-mandrel qualification per API 11D1 / ISO 14310.