Super Alloy Pyromet 680 (UNS N06002)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Fabrication and Heat Treatment
     Machinability
     Welding
     Heat Treatment
     Forging
     Hardening
Other Designations
Applications

Introduction

Pyromet alloy 680 is a nonmagnetic, heat and corrosion resistant, nickel-base alloy that exhibits excellent high temperature strength and oxidation resistance. It is resistant to stress-corrosion cracking. It is a solid solution strengthened alloy and develops optimum mechanical properties through a simple heat treatment.

The following section will provide an overview of Pyromet alloy 680.

Chemical Composition

The chemical composition of Pyromet alloy 680 is outlined in the following table.

Element Content (%)
Chromium, Cr 20.5-23
Iron, Fe 17-20
Molybdenum, Mo 8-10
Manganese, Mn 1
Silicon, Si 1
Aluminum, Al 0.5
Cobalt, Co 0.5-2.5
Copper, Cu 0.5
Tungsten, W 0.2-1
Titanium, Ti 0.15
Carbon, C 0.05-0.15
Phosphorus, P 0.04
Sulfur, S 0.03
Nickel, Ni Balance

Physical Properties

The following table shows the physical properties of Pyromet alloy 680.

Properties Metric Imperial
Density 8.22 g/cm3 0.297 lb/in3
Melting point 1260-1354°C 2300-2470°F

Mechanical Properties

The mechanical properties of Pyromet alloy 680 are displayed in the following table.

Properties Metric Imperial
Tensile strength (solution annealed) 114 MPa 16534 psi
Yield strength (solution annealed) 70 MPa 10153 psi
Elongation at break (solution annealed) 43% 43%

Thermal Properties

The thermal properties of Pyromet alloy 680 are given in the following table

Properties Metric Imperial
Thermal expansion co-efficient (@26-38°C/79-200°F) 13.86 µm/m°C 7.7 µin/in°F
Thermal conductivity 9.06 W/mK 62.8 BTU.in/hrft².°F

Fabrication and Heat Treatment

Machinability

Pyromet alloy 680 is machinable by conventional means and is similar to machining of the austenitic stainless steels.

Welding

The alloy can be welded using conventional processes such as shielded metal arc, resistance welding, and tungsten inert gas welding techniques.

Heat Treatment

The alloy is heat treated at (2150°F) and then rapidly cooled.

Forging

Forging of Pyromet alloy 680 can be carried out using conventional methods.

Hardening

The alloy can be hardened by cold working.

Other Designations

Other designations that are equivalent to Pyromet alloy 680 include the following:

AISI 680 ASTM B435 GE B50A436
AMS 5536 ASTM B572 GE B50A463
AMS 5587 ASTM B619 GE B50T83A
AMS 5588 ASTM B622 GE B50TF24
AMS 5754 ASTM B626 GE B50TF31
AMS 5798 DIN 2.4603 GE B50TF25
ASTM B366 DIN 2.4665 PWA 1038

Applications

The following are the list of applications of Pyromet alloy 680:

  • Petrochemical process equipment
  • Gas turbines
  • Afterburner components
  • Chemical industry.

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