SHS 9700 GMAW OAW is a multicomponent steel alloy with a unique uniform glass-forming melt chemistry that allows high undercooling to be achieved during welding. This results in considerable refinement of the crystalline microstructure down to a near nanosize (submicron) range. Unlike conventional weld overlay materials which are macrocomposites containing hard particles and general carbides in a binder, the refined microstructure of SHS 9700 does not incorporate distinct hard particles in a binder and is a uniformly hard matrix when welded. This allows SHS 9700 to provide vastly improved hardness and wear resistance that lasts significantly longer than conventional macrocomposites. Additionally, SHS 9700 is an iron-based alloy without tungsten carbide particulates.

High Hardness
Hardness performance of SHS 9700 is significantly better in multiple layer applications than in single layer applications. The micrograph to the right shows how maximum 69 HRc develops within 57.6 µm (0.0023”) of the weld overlay interface. HRc hardness values in the micrograph were measured from a single pass SHS 9700 GMAW weld overlay applied to an A36 steel plate.

High Wear Resistance
SHS 9700 can be built up in as many weld passes as necessary with the second and all subsequent layers providing maximum wear resistance of 0.12 - 0.14 g (+/- 0.03) mass loss in ASTM G65-04 Abrasion Tests.

Damage Tolerance
The superior toughness of SHS 9700 occurs from the in-situ formation of high-volume fraction of refined complex borocarbide phases during welding which are surrounded by ductile phases. The borocarbide phases, which form during solidification, are completely wetted by the matrix and prevent premature pull-out, delamination and crack nucleation. The refined nature of the borocarbide phases allows the reduction of stress concentration sites and the ductile matrix supplies effective crack blunting and bridging.

Hardness as a Function of Heat Treatment
The effect of exposure to elevated temperature for NanoSteel's SHS 9192 GMAW and SHS 9700 GMAW can be seen in the table to the right. SHS 9192 retains its hardness through temperatures of 1,000°F with only a small drop from the as welded hardness. SHS 9700 shows a larger drop initial drop in hardness but it then stays above 61 HRc through 1,000°F.

Weld Parameters
For SHS 9700 GMAW OAW weld parameters, contact NanoSteel at 1-877-293-NANO or info@nanosteelco.com.