Key Performance Characteristics

 
SHS 7270 features very high crack resistance while exhibiting high hardness and wear resistance. The eight element, glass forming alloy can be used alone for crack-free applications where high hardness and high wear resistance are needed in combination with high toughness. Alternatively, SHS 7270 can be used as a matrix material and mixed with tungsten carbide particulates for extreme abrasion applications.

Exceptional Resistance to Cracking/Cross Checking
SHS 7270 has been designed to exhibit exceptional resistance to cracking/cross checking during welding. When SHS 7270 was welded onto a 1/4” plate with and without a 600°F preheat, no cracking/cross checking was observed after dye penetrant inspection. Generally, no preheat is needed to prevent cracking/cross checking. But in cases where high thermal gradients occur, such as on thin parts, a 600°F preheat is recommended to eliminate cracking/cross checking.

High Hardness
Rockwell C (HRc) hardness measurements show that SHS 7270 weld deposits develop a refined microstructure which yields high hardness from 54 - 58 HRc.

High Wear Resistance
SHS 7270 has inherently good wear resistance due to the significant fraction (~ 40%) of borocarbide phases which form during welding. Wear resistance can be improved by mixing the base SHS 7270 material with various carbide blends. The photo to the right is an example of an SHS 7270 weld mixed with tungsten carbide particles before welding. The feedstock material was made by blending +45 / -150 µm acicular tungsten carbide (Duram FTC) particulates at 18 wt% to the SHS 7270 starting powder. Note that the amounts and types of carbide particles used are for demonstration purposes only and do not necessarily represent optimum conditions.

High Toughness
The distribution of very fine complex borocarbide phases surrounded by ductile ferrite spherical dendrite phases contributes to the high toughness of SHS 7270. Individual spherical dendrites in the PTAW structure of SHS 7270 are approximately 5 µm in size while the multiphase borocarbide interdendritic phases are very fine with an average length scale of less than a micron. During Palmqvist toughness studies using indentation loads up to 300 kg, no cracking was observed. SHS 7270 PTA welds solidify primarily through a dendritic mechanism with the interdendritic regions forming a multiphase cellular structure.

Weld Parameters
For SHS 7270 PTAW weld parameters, contact NanoSteel at 1-877-293-NANO or info@nanosteelco.com.