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National Advisory Committee for Aeronautics, Technical Notes - Tensile Stress-Strain Properties of 17-7 PH and AM 350 Stainless Steel Sheet at Elevated Temperatures

Tensile stress—strain test results are presented for 17-7 PH stainless-
steel sheet in the Condition TH 1,050 and for AM 550 stainless—steel sheet
in the double-aged condition for temperatures from room temperature to
1,5000 F. Stress—strain curves and data for yield and ultimate stresses,
Young's modulus, and elongation are given in tabular and graphical form.

A comparison is made between the tensile properties and the compressive
properties of NACA Technical Note MOTH.

Two precipitation-hardening stainless steels, 17-7 PH and AM 550,
show promise as aircraft structural materials for elevated—temperature
use. In addition to high strength and satisfactory ductility in the heat—
treated condition, these materials are corrosion resistant and can be
easily worked in the annealed condition. Conventional short-time elevated—
temperature data from various sources for these stainless steels and other
selected alloys are given in reference 1.

In the present investigation, short-time elevated—temperature tensile
data were obtained for 17-7 PH and AM 350 stainless-steel sheet from the
same sample material for which the compressive properties were determined
in reference 2. The 17—7 PH was in the Condition TH 1,050 and the AM 550
was double aged. The tensile stress-strain'curves and the tensile prop-
erties are given herein for temperatures up to 1,5000 F. A comparison
with the compressive properties is included.

Conventional tensile stress-strain tests were performed at room and
elevated temperatures. The equipment and pchedure_were essentially the
same as described in reference.5. The specimens were exposed to the test
temperature for 1/2 hour and then loaded to failure at a strain rate of
0.002 per minute. A stress-strain curve and a strain-time curve for each
test were recorded simultaneously on an autographic recorder. The strain—
time curve was used to control the strain rate during the test. The tem-
perature variations during the exposure period were within i'lOO F and
during the test within i5° F of the desired test temperature. Several
tests at room temperature were conducted with Tuckerman optical strain
gages to determine Young's modulus more'accurately.