POSTER REFERENCE: ICF100359PR DYNAMIC JR CURVES FROM INSTRUMENTED IMPACT TEST OF UNPRECRACKED CHARPY V-NOTCH SPECIMENS OF AUSTENITIC STAINLESS STEEL P. R. Sreenivasan, S. K. Ray and S. L. Mannan Materials Development Group, Indira Gandhi Centre for Atomic Resaearch, Kalpakkam, Tamilnadu-603 102,India Telephone:04114-40202/40232/40222 Fax.: 04114-40360/40396/40381/40356/40301 E-mail: mannan@igcar.ernet.in ABSTRACT. A new (shift) procedure has been suggested for obtaining the JR (J fracture resistance) curves of ductile alloys from the load-displacement traces of (unprecracked) CVN specimens (with CVN energy > 30 J) and demonstrated using instrumented impact test results from Charpy V-notch (CVN) and precracked CVN (PCVN) specimens of AISI 316 stainless steel. This involves generating the pseudo-JR curve from CVN specimens using a key-curve method and also by the procedure due to Schindler (Schindler curve). Then the pseudo-JR curve is shifted uniformly downward to bring it into coincidence with or slightly above the Schindler curve. This shift can be expressed as Jpseudo + Q.p, where p is the exponent in the power-law fitted to the pseudo-JR curve and Q takes values of − 2 to − 4. The shift-JR curves more truly reproduce the slopes of the PCVN-JR curves (hence tearing resistance) than the Schindler curves, though the latter are easy to generate. However, the range of applicability, size restrictions applicable and other aspects (like influence of loading rate, use of blunting line) need further validation using tests on different materials. When validated, the new method will obviate the need for expensive and time-consuming precracking, at least for select materials and test conditions. These methods will be useful not only for quality control purposes, but even for conservative engineering design. KEYWORDS. Stainless steel, Charpy V-notch, dynamic JR curve, key-curve, pseudo-JR curve, Schindler procedure 1. INTRODUCTION
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