Journal Published Online: 25 June 2018
Volume 7, Issue 1

Residual Strength and Fracture Toughness of 0.3C-CrMoV(ESR) Ultrahigh-Strength Steel Used for Solid Booster Motor Cases

CODEN: MPCACD

Abstract

0.3C-CrMoV(ESR) steel is an ultrahigh-strength low-alloy steel developed primarily for use as a cost-effective material for aerospace pressure vessel applications. These large-sized (Ø 2,800 mm) pressure vessels are manufactured by auto Tungsten Inert Gas (TIG) welding of plates/end domes. During the welding process, defects are likely to be generated, which will reduce the strength of the material. Therefore, residual strength in the presence of a possible missed defect has to be analyzed to qualify the pressure vessel for aerospace applications. In order to evaluate the residual strength and fracture toughness of welded specimens using surface crack tension specimens, mechanical tests were conducted as per the ASTM E740/E740M-03(2010) standard, Standard Practice for Fracture Testing with Surface-Crack Tension Specimens. Plates of 7.6 mm were TIG welded with filler wire matching the chemical composition of the base metal. The welded plates were hardened at 920 ± 10°C and tempered at 505 ± 5°C. The material exhibited a 0.2 % proof strength of 1,417 MPa, ultimate strength of 1,466 MPa, residual strength (σr) of 1,301 MPa, and apparent fracture toughness (KIe) of 86.5 MPa√m in the presence of a surface crack, sized 6 by 2 mm.

Author Information

Manikandan, P.
Material Characterization Division, Vikram Sarabhai Space Center, Trivandrum, India
Rao, G. Sudarsana
Material Characterization Division, Vikram Sarabhai Space Center, Trivandrum, India
Murty, S. V. S. Narayana
Material Characterization Division, Vikram Sarabhai Space Center, Trivandrum, India
Nayak, Goutam
Rocket Motors Fabrication Activities, Vikram Sarabhai Space Center, Trivandrum, India
Mishra, A. K.
Rocket Motors Fabrication Activities, Vikram Sarabhai Space Center, Trivandrum, India
Narayanan, P. Ramesh
Material Characterization Division, Vikram Sarabhai Space Center, Trivandrum, India
Ramkumar, P.
Materials and Metallurgy Group, Vikram Sarabhai Space Center, Trivandrum, India
Venkitakrishnan, P. V.
Materials and Mechanical Entity, Vikram Sarabhai Space Center, Trivandrum, India
Pages: 11
Price: $25.00
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Details
Stock #: MPC20170171
ISSN: 2379-1365
DOI: 10.1520/MPC20170171