Alloy G-30 Data Sheet

GENERAL PROPERTIES

With higher chromium, added cobalt and tungsten alloy G30 is an improved version of nickel-chromium-ironmolybdenum-copper alloy G-3. G-30 shows superior corrosion resistance over most other nickel and iron based alloys in commercial phosphoric acids as well as complex environments containing highly oxidizing acids. The resistance of the alloy to the formation of grain boundary precipitates in the heat-affected zone makes it suitable for use in most chemical process applications in the as-welded condition.

RESISTANCE TO CORROSION

Alloy G-30 provides very high resistance to the hydrofluoric acid and nitric acid solutions that are utilized in the stainless steel pickling. This specific application includes dilute 15% nitric acid and 5% hydrofluoric acid at temperature of 140°F or 60°C. It also offers superior resistance to the industrial phosphoric acid. The use of alloy has been increasing in the fertilizer industry for acid evaporators.

The relative resistance offered by alloy G-30 and alloy G or alloy 625 to the industrial acids is described in the varied concentrations, temperatures and pollution levels. The significant difference in the rate of corrosion is possible in the acids of equal amount though from dissimilar sources. The corrosion evaluation in the acids obtained from the different sources and functionality of G-30 alloy as compare to 625 alloy is described. Normally Alloy G-30 provides improved performance in the corrosive conditions.

PHYSICAL PROPERTIES

MECHANICAL PROPERTIES

CHEMICAL PROPERTIES

WELDING

Alloy G-30 is easily weldable through Gas Tungsten Arc welding, Gas Metal Arc welding and shielded metal arc welding methods. The welding features are similar to Alloy G-3. Submerged arc welding is not preferred because this procedure includes extensive heating of base metal and slows weld quenching.

Basic Metal: The joining surface and around space is cleaned properly for welding. Every kind of contaminant and foreign material like oil crayon marks, sulphur compounds and grease and other materials are removed.

Filter metals: Machining work filer metal is preferred for welding. For Gas Tungsten Arc welding, Gas Metal Arc welding, Alloy G-30 filler wire is recommended. For shielded metal arc welding, G-30 alloy covered electrodes are preferred.

HEAT TREATMENT

Alloy G-30 is capable of being annealed. However, this alloy must be solution-annealed after hot forming in order to restore its resistance to corrosion.