ABSTRACT
High-performance steels (HPS) were developed through a cooperative research program between the US
Navy, the Federal Highway Administration (FHWA), and the American Iron and Steel Institute (AISI).
At the time of this writing, two grades of HPS are available and have successfully been used in bridge
construction. Their ASTM designations are HPS50W and HPS70W (the equivalent metric designations
are HPS345W and HPS485W, respectively). A primary objective of developing HPS is to take advantage
of the higher strength offered by high-strength steels without compromising on weldability. Conven-
tional high-strength steels have a relatively high carbon content (approximately 19% by weight), and so
special attention is needed to obtain high quality welds. This typically requires preheating of the welded
parts, controlling the interpass temperature, controlling the energy input during passes, using special
electrodes, careful handling of the welding consumables, and if necessary applying postweld treatment
such as controlled cooling and feathering of the welds. When all operations are performed correctly and
all prescribed procedures are followed carefully, one can often obtain good quality welds in conventional
high-strength steels. Unfortunately, while these conditions can usually be met in a controlled envir-
onment such as in a shop, difficulties may arise when such welding has to be done on the field. This is
particularly the case for bridge construction, when welding under less than optimal condition is often the
norm. HPS have a carbon content that is very comparable to low carbon steel, and they can be welded
under a variety of conditions without requiring the rather time consuming and often expensive pre-and
postweld treatments. In addition, it has been demonstrated experimentally that HPS exhibit good
toughness and satisfactory ductility values for use as an effective construction material.
