Nickel Alloy Plate

Sandmeyer Steel Company stocks Alloy 825 nickel alloy plate in thicknesses from .1875" (4.8mm) through 2.00" (50.8mm) for corrosion resistant applications in the air pollution control, chemical and petrochemical, food processing, nuclear, offshore oil and gas production, ore processing, petroleum refining, steel pickling and waste disposal industries.

Available thicknesses for Alloy 825:

3/16" 1/4" 3/8" 1/2" 5/8" 3/4"
4.8mm 6.3mm 9.5mm 12.7mm 15.9mm 19mm
 
1" 1 1/4" 1 1/2" 1 3/4" 2"
25.4mm 31.8mm 38.1mm 44.5mm 50.8mm

Alloy 825 (UNS N08825) is an austenitic nickel-iron-chromium alloy with additions of molybdenum, copper and titanium. It was developed to provide exceptional corrosion resistance in both oxidizing and reducing environments. The alloy is resistant to chloride stress-corrosion cracking and pitting. The addition of titanium stabilizes Alloy 825 against sensitization in the as-welded condition making the alloy resistant to intergranular attack after exposure to temperatures in a range that would sensitize un-stabilized stainless steels. The fabrication of Alloy 825 is typical of nickel-base alloys, with material being readily formable and weldable by a variety of techniques.

Specification Sheet Overview

for Alloy 825 (UNS N08825)
W.Nr. 2.4858:
An Austenitic Nickel-Iron-Chromium Alloy Developed for Exceptional Corrosion Resistance In Both Oxidizing and Reducing Environments

Alloy 825 Nickel Alloy Plate

General Properties

Alloy 825 (UNS N08825) is an austenitic nickel-iron-chromium alloy with additions of molybdenum, copper and titanium. It was developed to provide exceptional resistance to numerous corrosive environments, both oxidizing and reducing.

The nickel content of Alloy 825 makes it resistant to chloride stress-corrosion cracking, and combined with molybdenum and copper, provides substantially improved corrosion resistance in reducing environments when compared to conventional austenitic stainless steels. The chromium and molybdenum content of Alloy 825 provides resistance to chloride pitting, as well as resistance to a variety of oxidizing atmospheres. The addition of titanium stabilizes the alloy against sensitization in the as-welded condition. This stabilization makes Alloy 825 resistant to intergranular attack after exposure in the temperature range which would typically sensitize un-stabilized stainless steels.

Alloy 825 is resistant to corrosion in a wide variety of process environments including sulfuric, sulfurous, phosphoric, nitric, hydrofluoric and organic acids and alkalis such as sodium or potassium hydroxide, and acidic chloride solutions.

The fabrication of Alloy 825 is typical of nickel-base alloys, with material readily formable and weldable by a variety of techniques.


Applications

  • Air Pollution Control
    • Scrubbers
  • Chemical Processing Equipment
    • Acids
    • Alkalis
  • Food Process Equipment
  • Nuclear
    • Fuel Reprocessing
      • Fuel Element Dissolvers
    • Waste Handling
  • Offshore Oil and Gas Production
    • Seawater Heat Exchangers
    • Piping Systems
    • Sour Gas Components
  • Ore Processing
    • Copper Refining Equipment
  • Petroleum Refining
    • Air-cooled Heat Exchangers
  • Steel Pickling Equipment
    • Heating Coils
    • Tanks
    • Crates
    • Baskets
  • Waste Disposal
    • Injection Well Piping Systems

Standards

ASTM..................B 424
ASME..................SB 424

Chemical Analysis

Typical Values (Weight %)

Nickel 38.0 min.–46.0 max. Iron 22.0 min.
Chromium 19.5 min.–23.5 max. Molybdenum 2.5 min.–3.5 max.
Molybdenum 8.0 min.-10.0 max. Copper 1.5 min.–3.0 max.
Titanium 0.6 min.–1.2 max. Carbon 0.05 max.
Niobium (plus Tantalum) 3.15 min.-4.15 max. Titanium 0.40
Carbon 0.10 Manganese 1.00 max.
Sulfur 0.03 max. Silicon 0.5 max.
Aluminium 0.2 max.

Physical Properties

Density

0.294 lbs/in3
8.14 g/cm3

Specific Heat

0.105 BTU/lb-°F
440 J/kg-°K

Modulus of Elasticity

28.3 psi x 106 (100°F)
196 MPa (38°C)

Magnetic Permeability

1.005 Oersted (μ at 200H)

 

Thermal Conductivity

76.8 BTU/hr/ft2/ft-°F (78°F)
11.3 W/m-°K (26°C)

Melting Range

2500 – 2550°F
1370 – 1400°C

Electrical Resistivity

678 Ohm circ mil/ft (78°F)
1.13 μ cm (26°C)

Linear Coefficient of Thermal Expansion

7.8 x 10-6 in / in°F (200°F)
4 m / m°C (93°F)

Mechanical Properties

Typical Room Temperature Mechanical Properties, Mill Annealed

Yield Strength
0.2% Offset
Ultimate Tensile
Strength
Elongation
in 2 in.
Hardness
psi (min.) (MPa) psi (min.) (MPa) % (min.) Rockwell B
49,000 338 96,000 662 45 135-165

Alloy 825 has good mechanical properties from cryogenic to moderately high temperatures. Exposure to temperatures above 1000°F (540°C) can result in changes to the microstructure that will significantly lower ductility and impact strength. For that reason, Alloy 825 should not be utilized at temperatures where creep-rupture properties are design factors. The alloy can be strengthened substantially by cold work. Alloy 825 has good impact strength at room temperature, and retains it’s strength at cryogenic temperatures.

Table 6 - Charpy Keyhole Impact Strength of Plate

Temperature Orientation Impact Strength*
°F °C ft-lb J
Room Room Longitudinal 79.0 107
Room Room Transverse 83.0 113
-110 -43 Longitudinal 78.0 106
-110 -43 Transverse 78.5 106
-320 -196 Longitudinal 67.0 91
-320 -196 Transverse 71.5 97
-423 -253 Longitudinal 68.0 92
-423 -253 Transverse 68.0 92

Corrosion Resistance

The most outstanding attribute of Alloy 825 is its excellent corrosion resistance. In both oxidizing and reducing environments, the alloy resists general corrosion, pitting, crevice corrosion, intergranular corrosion and chloride stress-corrosion cracking.

Resistance to Laboratory Sulfuric Acid Solutions

Alloy Corrosion Rate in Boiling Laboratory Sulfuric Acid Solution Mils/Year (mm/a)
10% 40% 50%
316 636 (16.2) >1000 (>25) >1000 (>25)
825 20 (0.5) 11 (0.28) 20 (0.5)
625 20 (0.5) Not Tested 17 (0.4)

Stress-Corrosion Cracking Resistance

The high nickel content of Alloy 825 provides superb resistance to chloride stress-corrosion cracking. However, in the extremely severe boiling magnesium chloride test, the alloy will crack after long exposure in a percentage of samples. Alloy 825 performs much better in less severe laboratory tests. The following table summarizes the alloy's performance.

Resistance to Chloride Stress Corrosion Cracking

Alloy Tested as U-Bend Samples
Test Solution Alloy 316 SSC-6MO Alloy 825 Alloy 625
42% Magnesium Chloride (Boiling) Fail Mixed Mixed Resist
33% Lithium Chloride (Boiling) Fail Resist Resist Resist
26% Sodium Chloride (Boiling) Fail Resist Resist Resist

Mixed – A portion of the samples tested failed in the 2000 hours of test. This is an indication of a high level of resistance.

Pitting Resistance

The chromium and molybdenum content of Alloy 825 provides a high level of resistance to chloride pitting. For this reason the alloy can be utilized in high chloride environments such as seawater. It can be used primarily in applications where some pitting can be tolerated. It is superior to conventional stainless steels such as 316L, however, in seawater applications Alloy 825 does not provide the same levels of resistance as SSC-6MO (UNS N08367) or Alloy 625 (UNS N06625).

Crevice Corrosion Resistance

Resistance to Chloride Pitting and Crevice Corrosion

Alloy Temperature of Onset at Crevice
Corrosion Attack* °F (°C)
316 27 (-2.5)
825 32 (0.0)
6MO 113 (45.0)
625 113 (45.0)

*ASTM Procedure G-48, 10% Ferric Chloride

Intergranular Corrosion Resistance

Alloy Boiling 65% Nitric Acid ASTM
Procedure A 262 Practice C
Boiling 65% Nitric Acid ASTM
Procedure A 262 Practice B
316 34 (.85) 36 (.91)
316L 18 (.47) 26 (.66)
825 12 (.30) 1 (.03)
SSC-6MO 30 (.76) 19 (.48)
625 37 (.94) Not Tested

Associations and Accreditations

ASME
Metals Service Center Institute Member 2016
NIAC
SSINA
Quality System Certificate
Pennsylvania Prosperity Project
Proud Member of the National Association of Manufacturers