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Description / Abstract:
Introduction
Note: Nothing in this standard supercedes
applicable laws and regulations.
Note: In the event of conflict between the
English and domestic language, the English language shall take
precedence.
Purpose. This standard was designed to evaluate
the susceptibility to secondary work embrittlement (SWE) and to
intergranular fracture at low temperature from impact loading of
ultra-low carbon, interstitial free, and rephosphorized steels. The
test may also be used to determine the ductile-to-brittle
transition temperature (DBTT) of any sheet steel that has
sufficiently high ductility to be deep-drawn.
Applicability. This test was initially designed
for the evaluation of any ultra-low carbon steel that is subject to
high drawing strains in part manufacture.
Ultra low carbon and rephosphorized grades of ultra-low carbon
steels can, under specific conditions, be susceptible to
intergranular cracking from impacts at low temperatures and from
cold forming of sheet steel that has previously been subjected to
large drawing strains during a previous forming process. This test
is designed to evaluate a steels susceptibility to these types of
failures through the determination of the ductile-to-brittle
transition temperature (DBTT).
There are many factors and conditions that can affect the DBTT.
The DBTT test described in this standard does not necessarily
correlate to field temperatures at which brittle fracture may
occur. This test only provides a method to evaluate the relative
performance of steels compared to those with established field
performance.
Remarks. The test consists of a series of cups
which are deep-drawn from a sheet of the test material. These cups
are cooled to various low temperatures and then subjected to a drop
test from a fixed height and with a constant weight. The highest
temperature at which the cups fracture in a brittle manner is
observed and recorded.