Incoloy alloy 825 UNS N08825/W.Nr.2.4858 ASTM B424 sheet bar tube

Overview

INCOLOY alloy 825 (UNS N08825/W.Nr. 2.4858) is a nickel-iron-chromium alloy with additions of molybdenum, copper, and titanium. This alloy is designed to provide exceptional resistance to many corrosive environments. The nickel content is sufficient for resistance to chloride-ion stress-corrosion cracking. The nickel, in conjunction with the molybdenum and copper, also gives outstanding resistance to reducing environments such as those containing sulfuric and phosphoric acids. The molybdenum also aids resistance to pitting and crevice corrosion. The alloy’s chromium content confers resistance to a variety of oxidizing substances such as nitric acid, nitrates and oxidizing salt. The titanium addition serves, with an appropriate heat treatment, to stabilize the alloy against sensitization to intergranular corrosion.

Limiting Chemical Composition, %

Nickel ......................................................................................................................................................................................................38.00-46.00

Iron.............................................................................................................................................................................................................22.00 min.

Chromium................................................................................................................................................................................................19.50-23.50

Molybdenum ...............................................................................................................................................................................................2.50-3.50

Copper .........................................................................................................................................................................................................1.50-3.00

Titanium.......................................................................................................................................................................................................0.60-1.20

Carbon..........................................................................................................................................................................................................0.05 max.

Manganese ..................................................................................................................................................................................................1.00 max.

Sulfur ...........................................................................................................................................................................................................0.03 max.

Silicon ..........................................................................................................................................................................................................0.50 max.

Aluminum.....................................................................................................................................................................................................0.20 max.

Physical Constants

Mechanical properties

INCOLOY alloy 825 has good mechanical properties from cryogenic temperatures to moderately high temperatures. Exposure to temperatures above about 1000°F (540°C) can result in microstructural changes (phase formation) that significantly lower ductility and impact strength. For that reason, the alloy is not normally used at temperatures where creep-rupture properties are design factors.

Compressive yield strength of the alloy is similar to tensile yield strength. Tests on annealed rod of 1.0-in. (25-mm) diameter produced a compressive yield strength (0.2% offset) of 61,400 psi (423 MPa) compared with a tensile yield strength of 57,500 psi (396 MPa). Ultimate tensile strength of the material was 104,500 psi (720 MPa).

INCOLOY alloy 825 has good impact strength at room temperature and retains its strength at cryogenic temperatures.

Tensile-properties

Corrosion Resistance

The outstanding attribute of INCOLOY alloy 825 is its high level of corrosion resistance. In both reducing and oxidize environments, the alloy resists general corrosion, pitting, crevice corrosion, intergranular corrosion, and stress-corrosion cracking. Some environments in which INCOLOY alloy 825 is particularly useful are sulfuric acid, phosphoric acid, sulfur-containing flue gases, sour gas and oil wells, and sea water

Heat treatment

The heat treatment process of Incoloy alloy 825 mainly includes solution treatment and aging treatment. Solution treatment is to heat the alloy to a certain temperature, so that all phases in the alloy are fully dissolved, and then quickly cooled to obtain a single-phase structure. Aging treatment is to heat the alloy after solid solution treatment to a certain temperature, so that the phase in the alloy is precipitated again to obtain the required mechanical properties.

During heat treatment, factors such as temperature, time and cooling rate affect the properties of Incoloy alloy 825. Therefore, it is necessary to determine the best heat treatment process parameters according to the specific alloy composition and product requirements.

Hot and Cold Forming

The hot-working range for INCOLOY alloy 825 is 1600 to 2150°F (870 to 1180°C). For optimum corrosion resistance, final hot working should be done at temperatures between 1600 and 1800°F (870 and 980°C).

Cooling after hot working should be air cool or faster. Heavy sections may become sensitized during cooling from the hot-working temperature, and therefore be subject to intergranular corrosion in certain media. A stabilizing anneal (see above)restores resistance to corrosion. If material is to be welded or subjected to further thermal treatment and subsequently exposed to an environment that may cause intergranular corrosion, the stabilizing anneal should be performed regardless of cooling rate from the hot-working temperature.

Cold-forming properties and practices are essentially the same for INCOLOY alloy 825 as for INCONEL alloy 600.Although work-hardening rate is somewhat less than for the common grades of austenitic stainless steels, it is still relatively high. Forming equipment should be well powered and strongly built to compensate for the increase in yield strength with plastic deformation.

Available Forms

We provide you with a variety of product forms, including but not limited to

● Bar & Rod

● Pipe & Tube

● Coil & Strip

● Plate & Sheet & Circle

● Wire & Welding

● Fitting (Flange, Elbow, Tee...)

● Customize