Ni-15Cr-7Fe-2.5Ti-0.7Al-1.0Nb+Ta (mass%)

Main Features

MA750 is an age-hardening Ni-Cr base alloy that shows, if it receives proper heat treatment, great stress rupture strength and small creep strength even at a high temperature of 816°C and under high stress . In addition, the alloy shows excellent resistance to chemical corrosion and oxidization. When precipitation hardening is performed to MA750 at 704°C, it achieves high strength. If the alloy is used at 593°C or below, higher strength can be realized by coupling cold-work and heat treatment. When using the alloy at 593°C or in higher temperatures, proper quality can be obtained by a three-step heat treatment . However, at 816°C or above , the alloy will lose most of its age-hardening property along with the increase in the temperature. Alloys which had solution treatment or direct aging will maintain their strength up to approximately 982°C.

Examples of applications

Gas turbine rotor blade, wheel, bolt, gas turbine parts, jet engine, ramjet rocket after-burner, pressure container, air roof frame, missile, heat treatment device, testing machine grip, spring material, bellows, honeycomb tray, extrusion dies, etc.


Since welding of these types of precipitation hardening alloys is difficult due to problems such as cracking after precipitation, welding must be performed before precipitation hardening. Weld efficiency is 80% or higher, but this efficiency will be cut greatly if various oxides are not removed before welding. Also, since the alloy has brittleness in high temperatures, each layer may require annealing or solution treatment when welding each layer.

Available Product Forms

Various shapes, such as flat-rolled plates, forgings, welding wires, wires, welded pipes and tubes, seamless pipes and tubes can be manufactured.


Information on specifications to which MA750 alloy can be ordered.


Bars, Forgings


Bars, Forgings


Plates Bars
G4902 G4901

AMS UNS N07750

Plates Bars, Forgings Pipes and Tubes Wires
5542 5667 5582 5698
5598 5668 5583 5699

Mechanical Properties, Physical Properties

Tensile properties in normal temperature

Heat treatment conditions Testing temperature (°C) Tensile strength
Yield strength(0.2% offset )
1149°C×2hr AC room temperature 122.0 83.0 27
843°C×24hr AC 538 107.0 73.8 26
704°C×20hr AC 649 95.6 72.4 10
760 73.1 54.5 8
871 33.1 21.2 18
982 10.0 6.2 31

Rupture test value

Breaking time(hr) Stress(kgf/mm2)
100 34.0
1000 26.6

Impact value(kgf•m)

Normal temperature 538°C 816°C
5.0 6.8 9.0

Physical Properties

Specific gravity Temperature range°C Specific heat cal/(g•°C) Coefficient of Thermal expansion 10-6/°C Electrical resistivity μΩ-cm
8.3 1395∼1425 Normal temperature 0.103
27°C∼93°C 12.1
27°C∼871°C 16.8

Degree of elasticity(kgf/mm2)

Normal temperature 538°C 816°C
21.8×103 18.8×103 16.3×103

Specific thermal conductivity(Cal/cm/sec/°C)

Normal temperature 538°C 816°C
0.029 0.045 0.057