Characterization of Material Properties of HPS-485W (70 W) TMCP for Bridge Girder Applications

There are currently two methods of production for A 709 Grade HPS-485W (70 W)-quenching and tempering (Q&T) and thermomechanical controlled processing (TMCP). The TMCP enables plates to be rolled in longer lengths than is possible with Q&T; however, because of its recent introduction and a lack of material testing, relatively little is known concerning the effect of this new production method upon the intraplate variability of both tensile strength and toughness. Data from 96 tensile tests show that yield and ultimate strengths of HPS-485W (70 W) TMCP may be dependent upon plate thickness and orientation. The average yield strength was found to be lower than the 485 MPa (70 ksi) limit, while the average ultimate strength was within acceptable limits. Seventy-five Charpy V-Notch (CVN) specimens were tested, and all met the 48 J at -23°C (35 ft-lb at 10°F) AASHTO Zone III requirement for minimum toughness. Overall it was seen that HPS 485W (70 W) TMCP shows promise for bridge girder applications, but thicker plates do not currently meet all the ASTM A 709 standards, and should be reevaluated before being used in bridge construction on a large scale.