STP1332

    Hydrogen Cracking During Service of High Strength Steel Cannon Components

    Published: Jan 1999


      Format Pages Price  
    PDF Version (564K) 16 $25   ADD TO CART
    Complete Source PDF (18M) 16 $129   ADD TO CART


    Abstract

    An investigation of environmental cracking during service of high strength steel cannon components is described. Two cases of cracking occurred in similar prototypes of an advanced cannon over a two year period. The materials, component configurations, applied and residual stresses, environmental conditions, and the resulting cracking behaviors and SEM fracture surface characteristics are outlined. Laboratory hydrogen cracking tests of the cannon materials, finite element stress analysis, and stress intensity factor calculations were used to model the hydrogen cracking. The first cracking incident involved cracks up to 21 mm long near a pressure seal in a 1160 MPa yield strength ASTM A723 forged steel cannon tube, following five firing cycles. The second incident involved 50 mm long cracks that after thirty firing cycles had grown near the seal between two adjoining cannon components, one made from A723 and one from 1280 MPa yield strength PH 13-8 Mo stainless steel. The cause of cracking, given the presence of hydrogen laden propellant products and susceptible high strength steels, was the sustained tensile stresses arising from assembly preloads required to maintain pressure seals between cannon components. Recommended preventative measures include reducing the strength level of the existing martensitic steels, changing to austenitic nickel-iron base alloys, and redesign to lower the level of sustained tensile stress concentrations in areas subjected to propellant environments.

    Keywords:

    hydrogen cracking, pressure vessels, high strength steel, environmental cracking threshold, crack growth rate, finite element analysis


    Author Information:

    Underwood, JH
    Development and Engineering Center, Benét Laboratories, Watervliet, NY

    Troiano, E
    Development and Engineering Center, Benét Laboratories, Watervliet, NY

    Vigilante, GN
    Development and Engineering Center, Benét Laboratories, Watervliet, NY

    Kapusta, AA
    Development and Engineering Center, Benét Laboratories, Watervliet, NY

    Tauscher, S
    Development and Engineering Center, Benét Laboratories, Watervliet, NY


    Paper ID: STP14990S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP14990S


    CrossRef ASTM International is a member of CrossRef.