UNS Number N06455

Hastelloy C-4 alloy is the most (microstructurally) stable of the widely used nickel-chromium-molybdenum materials, which are well known for their resistance to many aggressive chemicals, in particular hydrochloric acid, sulfuric acid, and chlorides. This stability means that the alloy can be welded without fear of sensitization, i.e. the nucleation and growth of deleterious, second phase precipitates in the grain boundaries of the weld heat-affected zone (HAZ).
Like other nickel alloys, it is ductile, easy to form and weld, and possesses exceptional resistance to stress corrosion cracking in chloride-bearing solutions (a form of degradation to which the austenitic stainless steels are prone). With its high chromium and molybdenum contents, it is able to withstand both oxidizing and non-oxidizing acids, and is resistant to pitting and crevice attack in the presence of chlorides and other halides.

Available Forms of Hastelloy C-4 at Rooplaxmi Steels:

• Round Bars
•  Sheet
•  Wires

Characteristics of Hastelloy C-4:

• Excellent resistance to stress-corrosion cracking and to oxidizing atmospheres at high temperature
•  Exceptional resistance to a wide variety of chemical process environments including, hot contaminated mineral acids, solvents, chlorine, formic and acetic acids, and salt waters.

Hastelloy C-4 Chemical Composition, %:

Ni	Co	Cr	Mo	Fe	Mn	Ti	Si
65 Balance	2 max	16	16	3 max	1 max	0.7 max	0.08 max

C	Cu
0.01 max	0.5 max

Application of Hastelloy C-4:

• Chemical processing

 

Machining and Fabrication with Hastelloy C-4:

Hastelloy C-4 alloy can be hot forged, hot rolled, hot upset, hot extruded, and hot formed. However, it is more sensitive to strain and strain rates than the austenitic stainless steels, and the hot working temperature range is quite narrow. For example, the recommended start temperature for hot forging is 1177°C (2150°F) and the recommended finish temperature is 954°C (1750°F). Moderate reductions and frequent re-heating provide the best results.

Hastelloy C-4 alloy is very amenable to the Gas Metal Arc (GMA/MIG), Gas Tungsten Arc (GTA/TIG), and Shielded Metal Arc (SMA/Stick) welding processes.

Hastelloy C-4 ASTM Specification:

Pipe Smls	Pipe Welded	Sheet/Plate	Bar	Fitting
SB 622/B 622	SB 619/B 619 SB 626/B 626	SB 575/B 575	SB 574/B 574	SB 366/B 366

Welding Wire Designations:
AWS A5.14 - ERNiCrMo7

Mechanical Properties of Hastelloy C-4:
At Room Temperature

Ultimate tensile strength	100 ksi or 690 Mpa
Yield strength	40 ksi or 276 MPa
Elongation	40 %