Inconel 693 (UNS N06693) - Alumina-Forming High Temperature Alloy Supplier of Bars, Tubes & Plates | Shanghai Hangbo Alloy Group
Date: 2026年8月6日 Categories: News Views: 336
By Shanghai Hangbo Alloy Group Co., Ltd. - China Supplier | ISO 9001:2015 | Est. 2012
Contact: sales@hangboalloy.com | hangbo@nickel-alloy.com | WhatsApp (Lisa): +86 13611656360
Quick Answer: What Is Inconel 693?
Inconel 693 (UNS N06693) is an alumina-forming nickel-chromium alloy with 29% chromium and 3.2% aluminum that provides exceptional resistance to hot hydrogen sulfide (H₂S) corrosion, metal dusting, and chlorination at temperatures up to 1000°C — environments that destroy chromia-forming alloys like Inconel 690 and 625. It is specified to ASTM B166/B168 and is the material of choice for petroleum refinery heater tubes, gasification units, and advanced petrochemical processes where sulfur and chlorine attack conventional nickel alloys. Shanghai Hangbo Alloy Group supplies Inconel 693 as round bars, seamless tubes, and plates.
Industry Pain Point: Petroleum refiners processing opportunity crudes (high-sulfur, high-chloride) face rapid degradation of heater tubes and transfer lines: conventional chromia-forming alloys (Inconel 600, 625, 800H) suffer catastrophic sulfidation and metal dusting in the 400-800°C range where H₂S and CO coexist. Inconel 693's alumina (Al₂O₃) protective scale — formed by its 3.2% aluminum — blocks both sulfur penetration and carbon diffusion (metal dusting), extending heater tube life from 2-3 years to 8-12 years in the same sour service.
Key Properties at a Glance
| Property | Value |
|---|---|
| UNS Number | N06693 |
| W.Nr. | 2.4649 |
| Alloy Family | Ni-Cr-Al (Alumina-Forming) |
| Density | 7.95 g/cm3 |
| Melting Range | 1345-1405C |
| Max Service Temp. | ~1000C (1830F) |
| Tensile (Ann.) | >= 700 MPa (102 ksi) |
| Yield (Ann.) | >= 350 MPa (51 ksi) |
| Elongation (Ann.) | >= 30% |
| Key Standards | ASTM B166, B168, B167 |
Product Overview
Inconel 693 was developed by Special Metals to solve the refinery and petrochemical problem that Inconel 690 could not: high-temperature sulfidation combined with metal dusting and chlorination. The alloy's metallurgical strategy mirrors that of Haynes 214 but tuned for process environments rather than pure oxidation:
- 29% Chromium: Forms the primary Cr₂O₃ scale for general oxidation resistance — higher than Inconel 600 (15%) and comparable to 690 (30%).
- 3.2% Aluminum: The signature element. At service temperature, aluminum diffuses to the surface and forms a continuous Al₂O₃ sub-layer beneath the chromia. This alumina barrier is nearly impermeable to sulfur and carbon, providing resistance to H₂S sulfidation and metal dusting that chromia alone cannot deliver.
- Niobium (0.5-2.5%) + Titanium (≤1.0%): Carbide formers that precipitate fine MC carbides for creep strength and provide additional stability.
The metal dusting mechanism (why 693 wins): Metal dusting is the catastrophic disintegration of metals in carbon-supersaturated atmospheres (CO + H₂ at 400-800°C). Carbon diffuses into the metal, precipitates as graphite, and the metal literally disintegrates into "dust." Alumina blocks this carbon ingress — Inconel 693 resists metal dusting where chromia formers fail within months.
Test data (laboratory metal dusting, 650°C, 1000 hours, high-carbon activity atmosphere):
| Alloy | Weight Loss (mg/cm²) |
|---|---|
| Inconel 693 | < 0.5 (negligible) |
| Inconel 600 | > 100 (disintegration) |
| Inconel 625 | ~ 20 |
| Inconel 690 | ~ 10 |
Shanghai Hangbo Alloy Group supplies Inconel 693 in bars, seamless tubes, and plates.
Executive Standards
| Product Form | ASTM | ASME |
|---|---|---|
| Bar & Rod | ASTM B166 | ASME SB-166 |
| Plate, Sheet & Strip | ASTM B168 | ASME SB-168 |
| Seamless Pipe & Tube | ASTM B167 | ASME SB-167 |
| Forgings | ASTM B564 | ASME SB-564 |
| Welding Filler | ERNiCrFe-7 (matching) | AWS A5.14 |
Chemical Composition (wt.%)
| Element | Min | Max | Role |
|---|---|---|---|
| Ni | Balance | -- | Matrix; sulfidation resistance |
| Cr | 27.0 | 31.0 | Cr₂O₃ scale; general oxidation |
| Al | 2.5 | 4.0 | Al₂O₃ sub-scale — sulfur/carbon barrier |
| Fe | 2.5 | 6.0 | Cost; structural |
| Nb | 0.5 | 2.5 | MC carbide strengthener |
| Ti | -- | 1.0 | Carbide former; stability |
| C | -- | 0.15 | Carbide strengthening |
| Mn | -- | 0.5 | Deoxidizer |
| Si | -- | 0.5 | Deoxidizer |
| S | -- | 0.02 | Impurity control |
Mechanical & Physical Properties
Room-Temperature (Solution-Annealed 1065-1120C/AC)
| Property | Value |
|---|---|
| Tensile Strength | >= 700 MPa (102 ksi) |
| Yield Strength 0.2% | >= 350 MPa (51 ksi) |
| Elongation | >= 30% |
| Hardness | ~90-100 HRB |
Elevated-Temperature (Typical)
| Temperature | Tensile (MPa) | Yield (MPa) |
|---|---|---|
| 20C | 850 | 450 |
| 650C | 620 | 270 |
| 800C | 350 | 180 |
| 950C | 110 | 60 |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.95 g/cm3 |
| Thermal Conductivity (20C) | ~12 W/m-K |
| Melting Range | 1345-1405C |
| Magnetic | Non-magnetic |
Heat Treatment
Solution Annealing: 1065-1120C (1950-2050F), rapid air cool or water quench. No precipitation hardening.
Pre-oxidation for maximum service life: Heat components to 1010C (1850F) for 2-4 hours in air before service to pre-form the Al₂O₃ sub-scale. This is standard practice for metal-dusting service and extends component life by 30-50%.
Production Process
1. Bars & Forgings
- Melting: VIM (Vacuum Induction Melting) for aluminum control — Al would be lost in air melt. ESR optional for premium quality.
- Hot Forging: 1100-1180C, finishing >=1000C, minimum 4:1 reduction.
- Solution Anneal: 1065-1120C, rapid cool. Hardness check.
- UT & Finishing: 100% UT per ASTM B166 for bars >=50mm. PMI every piece.
2. Seamless Tubes
- Extrusion: 1120-1180C.
- Cold Pilgering: Multi-pass with intermediate anneals.
- Final Anneal: 1065-1120C + rapid cool.
- Testing: 100% hydrostatic/ET. Flattening/flaring per ASTM B167.
Industry Applications
| Industry | Component | Why Inconel 693? |
|---|---|---|
| Petroleum Refining | Heater tubes, transfer lines (opportunity crude service) | H₂S sulfidation + metal dusting resistance in 400-800C sour service |
| Gasification | Syngas cooler internals, gasifier components | High-carbon-activity atmospheres — metal dusting immunity |
| Petrochemical | Steam reformer outlet manifolds, synthesis gas equipment | CO + H₂ atmospheres |
| Chemical | Chlorination reactor internals, HCl service | Chlorine resistance at elevated temperature |
| Heat Treatment | Furnace fixtures in carburizing atmospheres | Carburization + oxidation dual resistance |
Quality Assurance: 7-Stage
- Raw Material: Ni, Cr, Al, Nb analyzed by ICP-OES. Aluminum purity >=99.9%.
- VIM Melt: Al 2.5-4.0%, Cr +/-0.3%, Nb +/-0.2%, C <=0.10% internal.
- Hot Working: 1100-1180C, finishing >=1000C, reduction >=4:1.
- Solution Anneal: 1065-1120C verified, hardness 90-100 HRB.
- Metal Dusting Test: High-carbon-activity exposure test on request per lot.
- NDE: 100% UT bars >=50mm; ET/hydro tubes. PMI every piece.
- Documentation: EN 10204 3.1 MTC. SGS/TUV/BV witness.
Frequently Asked Questions
Q1: What is Inconel 693 used for?
Petroleum refinery heater tubes and transfer lines in high-sulfur (opportunity crude) service, gasification syngas coolers, petrochemical steam reformer equipment, and chlorination reactor internals — environments combining H₂S, CO, and chlorine at 400-1000°C.
Q2: What makes 693 special?
The 3.2% aluminum forms an Al₂O₃ sub-scale beneath the Cr₂O₃ layer that blocks sulfur and carbon diffusion — providing sulfidation and metal dusting resistance that chromia-formers cannot deliver.
Q3: Inconel 693 vs 690?
690: 30% Cr, 0.3% Al — chromia former, general oxidation. 693: 29% Cr, 3.2% Al — alumina former, sulfidation + metal dusting resistance. Upgrade to 693 for sour service.
Q4: Inconel 693 vs 625?
625 has excellent aqueous corrosion but poor metal dusting resistance. 693's alumina scale makes it superior in high-carbon-activity atmospheres.
Q5: What is the maximum service temperature?
~1000°C (1830°F) for continuous service.
Q6: Is it weldable?
Yes, with ERNiCrFe-7 matching filler. GTAW preferred.
Q7: What is the price?
$60-100/kg EXW. Contact sales@hangboalloy.com.
Q8: What product forms?
Bars (6-250mm), seamless tubes (OD 10-219mm), plates (3-50mm), forgings. SGS available.
Q9: Does it resist metal dusting?
Yes — laboratory tests show <0.5 mg/cm² weight loss at 650°C/1000h vs >100 mg/cm² for Inconel 600.
Q10: What is the density?
7.95 g/cm3.
Q11: What heat treatment?
Solution annealing at 1065-1120°C, rapid cool. Pre-oxidation at 1010°C recommended before service.
Q12: Does Shanghai Hangbo ship internationally?
Yes — FOB/CIF/DAP to 40+ countries.
Q13: Why aluminum at 3.2%?
Aluminum forms the protective Al₂O₃ sub-scale that blocks sulfur and carbon diffusion — the alloy's defining capability.
Q14: What standards apply?
ASTM B166 (bar), B168 (plate), B167 (tube), B564 (forgings).
Q15: How does it compare to Haynes 214?
Both are alumina-formers. 214 optimizes for cyclic oxidation to 1600°C. 693 optimizes for process corrosion (H₂S, metal dusting, chlorination) with better weldability and fabricability for process piping.
Contact Shanghai Hangbo Alloy Group
| Channel | Details |
|---|---|
| Company | Shanghai Hangbo Alloy Group Co., Ltd. - China Supplier |
| Website | www.nickel-alloy.com |
| Email (Sales) | sales@hangboalloy.com |
| Email (Technical) | hangbo@nickel-alloy.com |
| WhatsApp (Lisa) | +86 13611656360 |
| Address | Room 1508, No. 288 Shiyi Road, Baoshan District, Shanghai 200940, China |
Shanghai Hangbo Alloy Group - Complete Product Range
| Family | Available Grades |
|---|---|
| Pure Nickel | NI200, NI201, N4, N5, N6 |
| Monel | 400, 401, 404, K-500, R-405 |
| Inconel | 600, 601, 617, 625, 690, 693, 718, X-750, 725 |
| Incoloy | 800, 800H, 800HT, 825, 925, 926, A-286, 25-6HN, 27-7MO |
| Hastelloy | C-276, C-22, C-2000, C-4, G-30, G-35, X, B-2, B-3, B-4, N |
| Super Austenitic | 904L, Alloy 28, Alloy 31, 254SMO |
| Chromium-Rich | Alloy 33 |
| Nimonic | 75, 80A, 90, 95, 105, 115, 263 |
| Haynes | 25, 188, 214, 230, 242, 282, 556, HR-120, HR-160 |
| RA Series | RA330, RA333 |
| Precision | 1J22, 1J46, 1J50, 1J79, 1J85, 3J21, 4J32, 4J36, 4J45 |
| High-Strength | 18Ni250, 18Ni300, AerMet 100, PH13-8Mo |
| Heating | Cr20Ni80, Cr40Ni60 |
| Specialty | Alloy 20, Alloy 59, Inconel 686, 602CA |
Product Forms: Bars(6-500mm) | Tubes(OD 6-610mm) | Plates(0.1-100mm) | Forgings | Welded Pipes | Fittings | Wire(0.05-10mm) | Strip(0.02-4.0mm)
SGS/BV/TUV. Contact: sales@hangboalloy.com | WhatsApp (Lisa): +86 13611656360 | www.nickel-alloy.com
