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Alloy 625 (UNS N06625, 2.4856)

Applications

Industrial

Offshore Industry, Furnace Linings, Geothermal Power Plants, ect.

Features

Grade 1

  • Exceptional resistance to pitting, crevice corrosion, erosion and intergranular corrosion
  • Immunity to chloride-induced stress corrosion cracking
  • Good resistance to mineral acids such as nitric, phosphoric, sulfuric and hydrochloric acid
  • Good resistance to alkalis and organic acid
  • Good mechanical properties

Grade 2

  • Excellent creep strength above about 600°C
  • Good resistance to many types of hot gas corrosion, particularly chlorination

Material

Alloy 625 / UNS N06625 / 2.4856

Surface

Bright annealed / annealed

Package

Wooden case

Chemical composition (Nominal) %

Grade C Mn Si P S Cr Cb+Ta Co
Alloy 625 0.10 max 0.50 max 0.50 max 0.015 max 0.015 max 20.0-23.0 3.15-4.15 1.0 max
Mo Fe Al Ti Ni
8.0-10.0 5.0 max 0.40 max 0.40 max 58.0 min

Physical properties

Density 8.47 g/cm3 (0.306 lb/in3)

Heat treatment

Soft Annealing Solution Annealing
Alloy 625 is used in applications where the operating temperatures are below 600°C (1,112°F) in the soft annealed condition (grade 1). The soft annealing is carried out at temperatures of 950 to 1,050°C (1,742 to 1,922°F); a temperature of 980°C (1,796°F) is preferred. For applications above 600°C (1,112°F), the solution annealed variant of Alloy 625 (grade 2), which provides optimized creep strength, is used. The solution heat treatment should be carried out in the temperature range between 1,080°C and 1,160°C (1,976 and 2,120°F), preferably at 1,120°C (2,048°F).

Pipe and tube

Standard

ASTM B444 for seamless pipe and tube

Mechanical properties

Heat Treatment Tensile Strength, min, ksi (MPa) Yield Strength, min. (0.2% offset), min, ksi (MPa) Elongation in 2 in. or 50.8 mm (or 4 D), min, %
Grade 1 (annealed) 120 (827) 60 (414) 30
Grade 2 (solution annealed) 100 (690) 40 (276) 30

Round bar

Standard

ASTM B446

Mechanical properties

Heat Treatment Tensile Strength, min, ksi (MPa) Yield Strength, min. (0.2% offset), min, ksi (MPa) Elongation in 2 in. or 50 mm (or 4 D), min, %
Grade 1 (annealed)
Up to4		 120 (827) 60 (414) 30
Grade 1 (annealed)
Over 4 to 10		 110 (758) 50 (345) 25
Grade 2 (solution annealed) 100 (690) 40 (276) 30