UNS R31233 / Ultimet® Alloy Special Alloys For Automotive With Exceptional Resistance To Galling

Alloy UNS R31233 (W.Nr. 2.4681, Ultimet® Alloy) for automotive and locomotive fan blades, bolts, nozzle etc

1 PRODUCT

Alloy UNS R31233 (W.Nr. 2.4681, Ultimet® Alloy) for automotive and locomotive fan blades, bolts, nozzle etc.

Product available in forms of bar, rod, wire(profile, square, round, flat), bolts, plate, sheet, strip, forging billets, die etc.

2 APPLICATION

Typical application

Agitators, blenders, bolts, dies, extruders, fan blades, filters, glass plungers, nozzles, pumps, rolls, screw conveyors, and valve parts.

While UNS R31233 alloy has been used successfully in the form of wrought products, its largest applications have involved weld overlays, made with solid wire consumables and arcwelding processes such as GMAW (MIG) and GTAW (TIG).

3 OVERVIEW

UNS R31233 is a cobalt-based alloy with exceptional resistance to galling, cavitation erosion, slurry erosion, liquid droplet impact. Ideal welding material with exceptional ductility and resistance to weld cracking, very easy to apply as an overlay, multiple layers appliable with little to no preheat.

UNS R31233 provides a unique blend of properties. From a wear standpoint, it behaves like the STELLITE® alloys with lower carbon contents. From a corrosion standpoint, it possesses many of the attributes of the C-type and G-type HASTELLOY® materials, in particular outstanding resistance to chloride-induced pitting and crevice corrosion. Its mechanical and welding characteristics are much closer to those of the HASTELLOY® alloys than those of the STELLITE® alloys, whose low ductilities can be problematic.

4 CHEMICAL COMPOSITION (wt%):

5 PHYSICAL PROPERTY

Density: 0.306 lb/in³, 8.47 g/cm³

Melting Range: 2430- 2470°F (1332 -1354°C)

Modulus of elasticity: 31.2 x 10³ ksi (215 x 10³ MPa) in tension

6 MECHANICAL PROPERTY

Mechanical properties as per ASTM B815 and B818

Impact Strength

These impact strengths were generated using Charpy V-notch samples, machined from mill annealed plate of thickness 12.7 mm (0.5 in).

7 CORROSION RESISTANCE

The alloy exhibits very high resistance to chloride-induced pitting and crevice attack, forms of corrosion to which the austenitic stainless steels are particularly prone.

Sulfide stress cracking

Wrought UNS R31233 alloy has been tested according to NACE TM0177, which defines sulfide stress cracking as a room temperature phenomenon, resulting from hydrogen em- brittlement.

The TM0177 tests involved 5% NaCl + 0.5% glacial acetic acid, saturated with H₂S, proof- ring apparatus, and samples coupled to carbon steel and stressed to the point of yield.

UNS R31233 alloy was able to withstand these conditions, both annealed and cold-reduced (15%), indicating good resistance to hydrogen embrittlement.

H₂S induced stress corrosion cracking

Cracking at elevated temperatures in environments containing H₂S is defined as a form of

stress corrosion cracking.

Wrought UNS R31233 alloy has been tested in 20% NaCl + 0.517 MPa (75 psi) H S + 4.83 MPa (700 psi) CO₂, with and without 0.5 g/l sulfur, at 121°C and 177°C; the tests were conducted according to the recommendations of ASTM Standard G 39, the fixtures being made of UNS R31233 alloy, to prevent galvanic effects.

Like other materials, UNS R31233 alloy was prone to cracking in the cold-reduced condition, but resistant to H₂S induced stress corrosion cracking in the annealed condition, at these temperatures.

8 WORKING INSTRUCTION

Wrought products of UNS R31233 alloy are supplied in the Mill Annealed (MA) condition, unless otherwise specified. This solution annealing procedure has been designed to optimize the alloy’s corrosion resistance and ductility. Following all hot forming operations, the material should be re-annealed, to restore optimum properties. The alloy should also be reannealed after any cold forming operations that result in an outer fiber elongation of 7% or more.

The annealing temperature for UNS R31233 alloy is 1177°C (2150°F), and water quenching is advised (rapid air cooling is feasible with structures thinner than 10 mm (0.375 in). A hold time at the annealing temperature of 10 to 30 minutes is recommended, depending on the thickness of the structure (thicker structures need the full 30 minutes).

UNS R31233 alloy can be hot worked and cold worked. However, it is very strong, and work- hardens rapidly during cold working. The alloy may therefore require frequent, intermediate anneals, if cold working is employed. Please consult us for more details.

While cold work does not usually affect the resistance of UNS R31233 alloy to general cor-rosion, and to chloride induced pitting and crevice attack, it can affect resistance to stress corrosion cracking. For optimum corrosion performance, therefore, the re-annealing of cold worked parts (following an outer fiber elongation of 7% or more) is important.

9 STANDARD SPECIFICATION

ASTM B815 Billet, Rod & Bar

ASTM B818 / ASME SB818 Sheet, Plate & Strip

NACE MR0175 / MR0103

ISO 15156

10 COMPETITIVE ADVANTAGE:

(1) More than 50 years experience of research and develop in high temperature alloy, corrosion resistance alloy, precision alloy, refractory alloy, rare metal and precious metal material and products.
(2) 6 state key laboratories and calibration center.
(3) Patented technologies.
(4) Ultra-purity smelting process VIM + IG-ESR + VAR.

(5) High performance material.

11 BUSINESS TERM