ASTM G39-99(2016)
Standard Practice for Preparation and Use of Bent-Beam Stress-Corrosion Test Specimens

Standard No.

ASTM G39-99(2016)

Release Date

1999

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM G39-99(2021)

Latest

ASTM G39-99(2021)

Scope

5.1 The bent-beam specimen is designed for determining the stress-corrosion behavior of alloy sheets and plates in a variety of environments. The bent-beam specimens are designed for testing at stress levels below the elastic limit of the alloy. For testing in the plastic range, U-bend specimens should be employed (see Practice G30). Although it is possible to stress bent-beam specimens into the plastic range, the stress level cannot be calculated for plastically-stressed three- and four-point loaded specimens as well as the double-beam specimens. Therefore, the use of bent-beam specimens in the plastic range is not recommended for general use.

1.1 This practice covers procedures for designing, preparing, and using bent-beam stress-corrosion specimens.

1.2 Different specimen configurations are given for use with different product forms, such as sheet or plate. This practice is applicable to specimens of any metal that are stressed to levels less than the elastic limit of the material, and therefore, the applied stress can be accurately calculated or measured (see Note 1). Stress calculations by this practice are not applicable to plastically stressed specimens.

Note 1: It is the nature of these practices that only the applied stress can be calculated. Since stress-corrosion cracking is a function of the total stress, for critical applications and proper interpretation of results, the residual stress (before applying external stress) or the total elastic stress (after applying external stress) should be determined by appropriate nondestructive methods, such as X-ray diffraction (1).2

1.3 Test procedures are given for stress-corrosion testing by exposure to gaseous and liquid environments.

1.4 The bent-beam test is best suited for flat product forms, such as sheet, strip, and plate. For plate material the bent-beam specimen is more difficult to use because more rugged specimen holders must be built to accommodate the specimens. A double-beam modification of a four-point loaded specimen to utilize heavier materials is described in 10.5.

1.5 The exposure of specimens in a corrosive environment is treated only briefly since other practices deal with this aspect, for example, Specification D1141, and Practices G30, G36, G44, G50, and G85. The experimenter is referred to ASTM Special Technical Publication 425 (2).

1.6 The bent-beam practice generally constitutes a constant strain (deflection) test. Once cracking has initiated, the state of stress at the tip of ......

ASTM G39-99(2016) Referenced Document

• ASTM D1141 Standard Practice for the Preparation of Substitute Ocean Water
• ASTM G30 Standard Practice for Making and Using U-Bend Stress-Corrosion Test Specimens
• ASTM G36 Standard Practice for Evaluating Stress-Corrosion-Cracking Resistance of Metals and Alloys in a Boiling Magnesium Chloride Solution*， 2018-10-01 Update
• ASTM G44 Standard Practice for Exposure of Metals and Alloys by Alternate Immersion in Neutral 3.5?% Sodium Chloride Solution
• ASTM G50 Standard Practice for Conducting Atmospheric Corrosion Tests on Metals
• ASTM G85 Standard Practice for Modified Salt Spray (Fog) Testing

ASTM G39-99(2016) history

• 2021 ASTM G39-99(2021) Standard Practice for Preparation and Use of Bent-Beam Stress-Corrosion Test Specimens
• 1999 ASTM G39-99(2016) Standard Practice for Preparation and Use of Bent-Beam Stress-Corrosion Test Specimens
• 1999 ASTM G39-99(2011) Standard Practice for Preparation and Use of Bent-Beam Stress-Corrosion Test Specimens
• 1999 ASTM G39-99(2005) Standard Practice for Preparation and Use of Bent-Beam Stress-Corrosion Test Specimens
• 1999 ASTM G39-99 Standard Practice for Preparation and Use of Bent-Beam Stress-Corrosion Test Specimens