Manganese, silicon, and magnesium markedly reduce the tendency of Inconel 718 to weld microfissuring. By combining a manganese, 0.20 percent by content, with silicon, greater than 0.25 percent content, or by adding 20 ppm of magnesium, the weld microfissuring decreased in the standard alloy

Morrison, T. J.

Shira, C. S.

Weisenberg, L. A.

English

NASA Technical Reports Server

July 1968
A N A S TECH Ri EF
Brief 68-10251 
EN 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Weld Microfissuring in Inconel 718 Minimized by Minor Elements 
Inconel 718 is a commercial precipitation-harden-
able nickel-base alloy having good strength and ductil-
ity over a wide temperature range (_4230 to > 
1300°17). Because of these properties and its superior 
weldability and high resistance to strain-age cracking 
(compared to René 41) Inconel 718 has been used for 
parts requiring high strength at both cryogenic and 
elevated temperatures, particularly those which are 
machined and welded and then heat treated to develop 
required properties. 
Intergranular microfissures have been detected in 
the weld heat-affected zone of Inconel 718 forgings 
and plate by refined dye-penetrant and X-ray inspec-
tion techniques. Such microfissures have not been un-
common in other precipitation-hardenable nickel-base 
alloys and were shown to be measurably influenced by 
specific trace elements. An investigation was therefore 
undertaken to identify and establish the concentrations 
of trace (minor) elements which would minimize weld 
microfissuring in Inconel 718. The results of this in-
vestigation thus far show that a manganese content in 
excess of 0.20 percent combined with a silicon content 
greater than 0.25 percent markedly reduces the tend-
ency of Inconel 718 to weld microfissuring. Experi-
ments have also shown that the addition of 20 ppm of
magnesium significantly decreases weld microfissuring 
in the standard alloy. A 2100°F solution anneal, 
known to severely degrade standard Inconel 718 weld-
ability, had no appreciable effect on the weldability of 
the alloy with the added magnesium. Only electron-
beam welding, a most severe test of fissuring tendency, 
could cause the magnesium-modified alloy to fissure 
measurably. 
Note: 
Pertinent information on Inconel 718 is also con-
tained in Tech Briefs 67-10049 and 67-10282. In-
quiries on the microfissuring investigation may be 
directed to:
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B68-10251 
Patent status: 
No patent action is contemplated by NASA. 
Source: T. J. Morrison, C. S. Shira, 
and L. A. Weisenberg 
of North American Rockwell Corporation 
under contract to 
Marshall Space Flight Center 
(MFS-18185) 
Category 03 
mr
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19680000251 2020-03-12T06:04:59+00:00Z
• rs-cAs-42n 
RM. 1313	 KS C FIQS..


Weld microfissuring in Inconel 718 minimized by minor elements

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server