Super Alloy HAYNES 625 (UNS N06625)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
     Machinability
     Forming
     Heat Treatment
     Forging
     Welding
     Annealing
     Hot Working
     Cold Working
Applications

Introduction

Super alloy HAYNES 625 is a nickel-chromium-molybdenum wrought alloy. It is an excellent general purpose material that is ideal for high temperature use in high strength, oxidation problem applications. HAYNES 625 also has excellent corrosion resistance to several acids and resists stress-corrosion cracking and intergranular attack. It can be used in short term applications at temperatures of up to 815°C (1500°F) as well.

The following sections will discuss in detail about super alloy HAYNES 625.

Chemical Composition

The chemical composition of HAYNES 625 is outlined in the following table.

Element Content (%)
Nickel, Ni 62
Chromium, Cr 21
Molybdenum, Mo 9
Iron, Fe ≤ 5
Tantalum, Ta 3.7
Niobium, Nb 3.7
Cobalt, Co ≤ 1
Manganese, Mn ≤ 0.50
Silicon, Si ≤ 0.50
Titanium, Ti ≤ 0.40
Aluminum, Al ≤ 0.40
Carbon, C ≤ 0.10

Physical Properties

The physical properties of HAYNES 625 are tabulated below.

Properties Metric Imperial
Density 8.44 g/cm3 0.305 lb/in3
Melting point 1290 - 1350°C 2350 - 2460°F

Mechanical Properties

The following table shows mechanical properties of HAYNES 625.

Properties Metric Imperial
Tensile strength 915 MPa 133000 psi
Yield strength 425 MPa 61600 psi
Elastic modulus 208 GPa 30200 ksi
Elongation at break 46% 46%

Thermal Properties

The thermal properties of HAYNES 625 are tabulated below.

Properties Metric Imperial
Thermal expansion co-efficient (@25-200°C/77-392°F) 12.8 µm/m°C 7.11 µin/in°F
Thermal conductivity 9.80 W/mK 68 BTU in/hr.ft².°F

Other Designations

Equivalent materials to HAYNES 625 are tabulated below:

AMS 5599 AMS 5837 AMS 5879 ASTM B443 ASTM B444
AMS 5581 AMS 5666 ASTM B366 ASTM B446 ASTM B704
ASTM B705 DIN 2.4856 GE B50TF133 MIL E-21562 (RN625)

Fabrication and Heat Treatment

Machinability

HAYNES 625 can be machined using conventional processes. This alloy tends to work harden ahead of cutting, and hence rigid tooling is required to prevent chatter and work hardening.

Forming

HAYNES 625 can be cold formed using conventional processes and tooling.

Heat Treatment

HAYNES 625 can be heat treated in the solution annealed condition at 1177°C (2150°F) for a specific amount of time depending upon the section thickness of the material. This process has to be followed by annealing the alloy and air cooling.

Forging

Hot forging can be done by heating the material to 1149-1176°C (2100-2150°F). Heating should not exceed 1176°C (2150°F). It is recommended that heavy forging be performed down to a temperature of 1010°C (1850°F) while light forging down to 926°C (1700°F).

Welding

Welding of HAYNES 625 can be performed using all the traditional welding methods. It is recommended that a matching alloy filler metal be used.

Annealing

Annealing can be performed at 982-1093°C (1800-2000°F) and air cooled. Stress relief of cold worked parts can be performed at 593-760°C (1100-1400°F).

Hot Working

Hot working can be performed by heating the alloy to 1177°C (2150°F). As this alloy possesses good strength at high temperatures, it tends to resist hot deformation and hence powerful tools are required.

Cold Working

HAYNES 625 can be cold formed using the traditional methods and tooling.

Applications

HAYNES 625 is used in high temperature applications such as heat exchangers and gas turbine components. This alooy’s good corrosion resistance makes it ideal for use in wet scrubbers and certain acid process equipment.

HAYNES 625 is commonly used in the following industries:

  • Aerospace industry
  • Chemical process industry
  • Power industry.

Tell Us What You Think

Do you have a review, update or anything you would like to add to this article?

Leave your feedback
Submit