Alloy 926
Alloy 926 ( Material No. 1.4529) is a austenitic (face-centered cubic structure), stainless special steel . This stainless steel is a further development of Alloy 904l (1.4539). However, the molybdenum content was increased to 6.5% and the material was provided with 0.2% nitrogen. Thisimprovedthe resistance to pitting and crevice corrosion . The resistance to stress corrosion cracking inducedby pitting corrosion also increases.
The UNS number of the material is N08926. Other brand names are Alloy 6Mo and Cronifer 1925hMo .
This material was developed by ThyssenKrupp VDM (now VDM Metals ) in the 1980s. A similar material is Alloy 254SMO (1.4547), which was developed by Avesta in Sweden. However, this has a lower nickel content.
Main areas of application for Alloy 926
Alloy 926 is mainly used in:
- Concentration and crystallization systems for salt production by evaporation
- Condenser tubes and piping systems in power plants with heavily contaminated cooling water
- Pump rods for oil production systems
- Evaporators, heat exchangers , tank linings and in phosphoric acid production
- Tanks for the transport of aggressive chemical products
- Distribution systems and coolers for sulfuric acid plants
- Fire extinguishing systems, seawater filtration, hydraulic and injection systems for offshore technology
- Flexible pipes in the offshore industry
- in swimming pools
In swimming pool construction, the material was included in the building standard after the accident in Uster and is now mandatory. In the accident, the ceiling of the indoor pool fell down while the pool was in use, and many people were killed. The reason for this was chlorine-induced stress corrosion cracking .
Alloy 926 is characterized by:
- Approval for pressure vessels with temperatures between −196 and 400 ° C
- increased resistance to stress corrosion cracking compared to other austenitic stainless steels
- excellent general corrosion resistance in the area of oxidizing and reducing media
- less tendency to form intermetallic phases compared to similar steels with only 18% nickel
- very good resistance to pitting and crevice corrosion
- Building authority approval for components and fasteners made of stainless steels, Deutsches Institut für Bautechnik , September '98
Chemical composition of Alloy 926
| C 0 - 0.02% | Si 0 - 0.5% | Mn 0 - 1.0% | P 0 - 0.03% | S 0 - 0.005% | Cr 20.0 - 21.0% |
| Mo 6.0 - 6.8 | Ni 24.5 - 25.5% | N 0.18 - 0.2% | Cu 0.8 - 1.0% | Fe rest |
Special properties of Alloy 926
| Temperature range | High temperature range |
| Melting temperature range | 1320-1390 ° C |
| density | 8.14 g / cm³ |
| ISO-V notched impact strength | Mean value at RT longitudinally and transversely ≥ 150 J / cm² |
The material has ISO 15156 / NACE MR0175 Class 5 for sour gas applications in the oil and gas industry and is described in VdTÜV information sheet 502. The effective sum is 47.
Welding consumables (for welding with Alloy 926)
With the following welding consumables can welded are:
- SG-NiCr23Mo16, material no. 2.4607, AWS A5.14, ERNiCrMo-13
- EL-NiCr22Mo16, material no. 2.4609, AWS A5.11, ENiCrMo-13
- SG-NiCr21Mo9Nb, material no. 2.4831, FM 625, AWS A5.14, ERNiCrMo-3
- EL-NiCr20Mo9Nb, material no. 2.4621, AWS A5.11, ENiCrMo-3
Welding processes: TIG, TIG hot wire, plasma, MIG / MAG, UP and MMA.
Individual evidence
- ↑ Material Data Sheet VDM Metals (PDF; 460 kB), to the material data sheet .
- ↑ Homepage , brief overview.