The Charpy V-notch impact test is often used to evaluate the brittleness of the 9% nickel steel, which is subjected to extremely rapid strain rate especially at cryogenic temperatures. It shall be conducted in accordance with ASTM E23. The V-notched specimen can measure the resistance of the material to crack propagation. During the test, absorbed energy, lateral expansion, and fracture appearance are obtained from a 10 mm x 10 mm x 55 mm piece of 9% nickel alloy steel bar subjected to impact loading. The impact energy absorbed reflects the impact toughness of the material.

Charpy V-Notch Impact Test Data Range for 9% Nickel Steel

The probable ranges of Charpy V-notch impact values for double normalized & tempered and quenched & tempered 9% nickel alloy steel are presented in above illustrations. The specimens are tested both longitudinally and transversely, while the normal expectancy curve is plotted. The tests are performed at a temperature range from -320°F to room temperature.

Charpy Impact Tests for 9-Ni Steel Plates of Different Thicknesses

The specimens are taken from quenched and tempered 9% nickel steel plates with the thickness of 0.4″, 0.5″, 0.9″, 1.6″, 1.9″ and 2″ respectively. Both longitudinal and transverse V-notch impact tests are performed at -320°F. The test results are recorded in below table, showing the effect of plate thickness on Charpy impact values.

Plate Thickness	Longitudinal		Transverse
inch	Each (ft*lb)	Average (ft*lb)	Each (ft*lb)	Average (ft*lb)
0.4	31~38	45	-	-
0.5	28~46	38	27~36	32
0.9	45~50	48	34~39	36
1.6	41~50	45	30~31	30
1.9	30~47	35	26~31	28
2.0	32~48	40	20~25	22

*The absorbed energy of each specimen and the average of the three specimens shall be calculated.

Effect of Heat Treatment & Rolling Direction on Charpy V-Notch Impact Test of 9% Nickel Steel

The test pieces are taken from 9% nickel alloy steel plates manufactred to ASTM A353 (NNT) or ASTM A553 Type I (QT), respectively. The longitudinal and transverse charpy values are shown by the curves plotted. Test temperature: -320°F ~ room temperature; Specimen thickness: 0.5 inch.