scope:

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.