STP1248

    The Role of Strike Marks on the Reproducibility of Charpy Impact Test Results

    Published: Jan 1995


      Format Pages Price  
    PDF Version (260K) 16 $25   ADD TO CART
    Complete Source PDF (4.9M) 16 $96   ADD TO CART


    Abstract

    Charpy V-notch specimens from one lot of high-strength steel were tested using three machines to determine reference values for three measures of toughness: absorbed energy, lateral expansion, and height of shear lips. The broken specimens were examined to determine the location and magnitude of changes in specimen features made during testing. The features of interest were the height and location of the shear lips, the location of the lateral expansion projections ranked by height, and the location, length, width, and angle of the first- and second-strike marks. Changes in these features were compared to the changes in average absorbed energy for each of the machines in its standard condition. To correlate changes in these features with intentional machine modifications, ten series of tests were made on a fourth machine. Patterns which could predict the direction of change in absorbed energy for most modifications were observed. The trends indicated by these data are: (1) each modification resulted in an increase in absorbed energy, (2) the distance between second-strike marks is a measure of the compliance of the striking edge and anvil, (3) the offset of the first-strike marks is largely due to lift-off of the specimen at the moment the striker hits the specimen, (4) offset and the angle of second-strike marks are measures of general asymmetry of loading, and (5) lateral expansion and shear lips are valuable as means to detect scale errors and excess losses not related to the work of fracture.

    Keywords:

    Absorbed energy, Charpy V-notch, high-strength steel, high-speed photography, impact machine, lateral expansion, shear lips, strike marks


    Author Information:

    Schmieder, AK
    Consultant, Scotia, NY

    Purtscher, PT
    Physical Scientist and ASTM Charpy Program Coordinator, NIST, Boulder, Colorado

    Vigliotti, DP
    Physical Scientist and ASTM Charpy Program Coordinator, NIST, Boulder, Colorado


    Paper ID: STP14653S

    Committee/Subcommittee: E28.07

    DOI: 10.1520/STP14653S


    CrossRef ASTM International is a member of CrossRef.