Super Alloy Hastelloy(r) G50(r) (UNS N06950)

Topics Covered

Introduction
Chemical Composition
Physical properties
Mechanical Properties
Thermal Properties
Fabrication and Heat Treatment
     Machinability
     Forming
     Welding
     Cold Working
     Annealing
     Hardening
Applications

Introduction

Super alloys or high performance alloys have the capacity to function at high temperatures and extreme mechanical stress, and also where high surface stability is required. They are available in different shapes, and have good creep and oxidation resistance. Solid-solution hardening, work hardening, and precipitation hardening are performed for improving strength of this alloy.

Hastelloy(r) G50(r) is a nickel-chromium-molybdenum and iron alloy. The following datasheet gives an overview of hastelloy(r) G50(r).

Chemical Composition

The chemical composition of hastelloy (r) G50(r) is outlined in the following table.

Elements Content (%)
Nickel, Ni ≥ 50
Chromium, Cr 19-21
Iron, Fe 15-20
Molybdenum, Mo 8-10
Cobalt, Co ≤ 2.50
Manganese, Mn ≤ 1
Silicon, Si ≤ 1
Tungsten, W ≤ 1
Niobium, Nb ≤ 0.50
Copper, Cu ≤ 0.50
Aluminum, Al ≤ 0.40
Phosphorous, P ≤ 0.040
Carbon, C ≤ 0.020
Sulfur, S ≤ 0.015

Physical properties

The physical properties of hastelloy(r) G50(r) are given in the following table.

Properties Metric Imperial
Density 8.33 g/cm³ 0.301 lb/in³
Melting point 1399°C 2550°F

Mechanical Properties

The following table shows the mechanical properties of Hastelloy(r) G50(r).

Properties Metric Imperial
Tensile strength ≥ 760 MPa ≥ 110000 psi
Yield strength (@ strain 0.200%) 700-860 MPa 102000-125000 psi
Elastic modulus (room temp.) 192 GPa 27800 ksi
Elongation at break (in 50 mm) ≥ 20% ≥ 20%
Hardness, Brinell (estimated from Rockwell C for Brinell 10 mm ball/3000 kg load) 290 290
Hardness, Knoop (estimated from Rockwell C) 345 345
Hardness, Rockwell A (estimated from Rockwell C) 66 66
Hardness, Rockwell C ≤ 31 ≤ 31
Hardness, Vickers (estimated from Rockwell C) 300 300

Thermal Properties

The thermal properties of hastelloy(r) G50(r) are displayed in the following table.

Properties Metric Imperial
Thermal expansion co-efficient (@ 20-95°C/68- 03°F) 13.0 µm/m°C 7.22 µin/in°F

Fabrication and Heat Treatment

Machinability

Hastelloy(r) G50(r) is machined using conventional methods which are used for iron-based alloys. It has machining characteristics similar to that of austenitic stainless steels.

Forming

Hastelloy(r) G50(r) can be formed using conventional methods.

Welding

Hastelloy (r) G50(r) is welded using gas tungsten arc welding, metal-arc welding, and shielded metal-arc welding methods. Submerged-arc welding method is not preferred for this alloy.

Cold Working

Hastelloy (r) G50(r) can be cold worked using standard tooling. Soft die materials such as zinc alloy and bronze are used for reducing galling problems.

Annealing

Hastelloy(r) G50(r) is annealed at 1149°C (2100°F) followed by rapidly cooling or quenching in water.

Hardening

Hastelloy(r) G50(r) is hardened by cold working.

Applications

Hastelloy(r) G50(r) is suitable for oil production applications.

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