Investigation determined whether irradiated pressure-vessel steels 4340 and 212-B are susceptible to hydrogen embrittlement and to catastrophic failure. Hydrogen-charging conditions which completely embrittled 4340 steel had negligible effect on 212-B steel in tensile and delayed-failure tests

Rossin, A. D.

English

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June 1968
	 Brief 68-10194 
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Susceptibility of Irradiated Steels to Hydrogen Embrittlement 
An investigation was conducted to determine 
whether irradiated pressure-vessel steels 4340 and 
212-B could become susceptible to hydrogen embrit-
tlement, and if these irradiated structures would then 
be susceptible to catastrophic failure. Knowledge of 
the effect of irradiation on various types of steel is 
extremely important for reactor safety. 
The results of the investigation are contained in the 
report, Hydrogen Embriulement in Irradiated Steels, 
by A. D. Rossin, ANL-7266, February 1967, Argonne 
National Laboratory, Argonne, Illinois. This report 
completely presents the very specialized area of hydro-
gen embrittlement of 4340 and 212-B steels. Back-
ground information, experimental procedures, testing 
results, and possibilities for future work are included. 
Two very different steels were examined. A high-
strength steel, quenched and tempered 4340, was 
chosen because its behavior when charged with hydro-
gen is well known and documented. It was irradiated, 
then hydrogenated and tested in a manner which had 
previously revealed catastrophic embrittlement. 
Steel 212-B was chosen because of its use as a vessel 
material in a number of pressurized- and boiling-
water reactors. Further, fully documented material 
was available. Samples of 212-B were exposed to an 
irradiation dose large enough to raise its ductile-
brittle transition temperature well above room tem-
perature to cause a substantial increase in its yield 
and tensile strength. It was then hydrogenated and 
tested in the manner that results in catastrophic fail-
ure in 4340. 
Hydrogen-charging conditions which completely 
embrittled 4340 high-strength steel had negligible 
effect on 212-B pressure vessel steel in tensile and
delayed-failure tests. Much higher hydrogen charges 
reduced the notch-tensile strength slightly. Delayed 
failure was observed only at stresses above 90% of the 
notch-tensile strength of the hydrogenated 212-B. 
Tests on 212-B, which had been irradiated to give a 
35% increase in strength and an NDT temperature 
shift of 94 0 C, showed the same relationship between 
delayed-failure limits and notch-tensile strength as 
that observed without irradiation. 
Catastrophic embrittlement due to hydrogen was 
not observed in 212-B, even for irradiated material 
that had been charged to produce high hydrogen 
content. Therefore, catastrophic hydrogen embrittle-
ment of a well-designed nuclear-reactor pressure 
vessel is not probable. 
The notch-tensile strength of 4340 steel was reduced 
by irradiation, although the tensile strength increased. 
Catastrophic delayed failure still occurred, but the 
sensitivity to hydrogen was slightly reduced. 
Notes: 
I. This report is available from the Clearinghouse 
for Federal Scientific and Technical Information, 
Springfield, Va. 22151; price $3.00 (microfiche 
copies, $0.65). 
2. Inquiries concerning this innovation may be di-
rected to:
Office of Industrial Cooperation 
Argonne National Laboratory 
9700 South Cass Avenue 
Argonne, Illinois 60439 
Reference: B68-10194 
Source: A. D. Rossin

Metallurgy Division

(ARG-101 15) 
(continued overleaf) 
This document was prepared under the sponsorship of the Atomic 
Energy Commission and/or the National Aeronautics and Space 
Administration. Neither the United States Government nor any per-
son 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 the use of any information, apparatus, 
method, or process disclosed in this document may not infringe pri-
vately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19680000194 2020-03-12T05:37:26+00:00Z
Patent status: 
Inquiries about obtaining rights for commercial 
use of this innovation may be made to: 
Mr. George H. Lee, Chief 
Chicago Patent Group 
U.S. Atomic Energy Commission 
Chicago Operations Office 
9800 South Cass Avenue 
Argonne, Illinois 60439 
Brief 68-10194	 Category 03


Susceptibility of irradiated steels to hydrogen embrittlement

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