Ductile vs. Brittle Behavior—Body-centered-cubic or ferritic alloys exhibit a significant transition in behavior when impact tested over a range of temperatures. At temperatures above transition, impact specimens fracture by a ductile (usually microvoid coalescence) mechanism, absorbing relatively large amounts of energy. At lower temperatures, they fracture in a brittle (usually cleavage) manner absorbing appreciably less energy. Within the transition range, the fracture will generally be a mixture of areas of ductile fracture and brittle fracture.

The temperature range of the transition from one type of behavior to the other varies according to the material being tested. This transition behavior may be defined in various ways for specification purposes.

The specification may require a minimum test result for absorbed energy, fracture appearance, lateral expansion, or a combination thereof, at a specified test temperature.

The specification may require the determination of the transition temperature at which either the absorbed energy or fracture appearance attains a specified level when testing is performed over a range of temperatures. Alternatively the specification may require the determination of the fracture appearance transition temperature (FATTn) as the temperature at which the required minimum percentage of shear fracture (n) is obtained.

Further information on the significance of impact testing appears in Annex A5.

1. Scope

1.1 These test methods cover procedures and definitions for the mechanical testing of steels, stainless steels, and related alloys. The various mechanical tests herein described are used to determine properties required in the product specifications. Variations in testing methods are to be avoided, and standard methods of testing are to be followed to obtain reproducible and comparable results. In those cases in which the testing requirements for certain products are unique or at variance with these general procedures, the product specification testing requirements shall control.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ISO Standard

ASME Document

ASTM Standards

Index Terms

bend test; Brinell hardness; Charpy impact test; elongation; FATT (Fracture Appearance Transition Temperature); hardness test; portable hardness; reduction of area; Rockwell hardness; tensile strength; tension test; yield strength; Steel wire; Temperature tests--metals/alloys; Tensile properties/testing--steel; Tin mill products; Yield strength and yield point; Bend testing--metallic materials; Brinell hardness; Charpy impact test; Elongation--metallic materials; Forgings; Fracture appearance transition temperature (FATT); Generator materials; Hardness (indentation)--metallic materials; Impact resistance; Impact testing--Charpy; Mechanical analysis/testing; Pressure vessel steel; Railroad steel materials; Rockwell hardness; Seven-wire strand (tendon); Shipbuilding steel materials--specifications; Steel; Steel bars; Steel bolting materials; Steel chain; Steel pipe; Steel sheet; Steel sheet/strip; Steel sheet/strip/plate; Steel tube; Steel valves;

ICS Code

ICS Number Code 77.040.10 (Mechanical testing of metals); 77.140.01 (Iron and steel products in general)

Citing ASTM Standards

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