Heat-Affected Zone Formation in Electrospark-Deposition Additive Manufacturing on Ultrahigh-Strength Steel
| Autor: | T. Langston, J. Kadali, W. E. Wood, Benjamin Adam, R. Talla |
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| Rok vydání: | 2017 |
| Předmět: |
Heat-affected zone
Materials science Polymers and Plastics Metallurgy Alloy Metals and Alloys Substrate (electronics) Welding engineering.material Indentation hardness Corrosion law.invention Mechanics of Materials law Stellite Ceramics and Composites engineering Composite material Electrospark deposition |
| Zdroj: | Materials Performance and Characterization. 6:MPC20160038 |
| ISSN: | 2165-3992 |
| DOI: | 10.1520/mpc20160038 |
| Popis: | Electrospark deposition (ESD), an additive microweld-surfacing process, is typically used as a new or repair technology to enhance wear and corrosion resistance for build-up and special surface modifications. ESD employs short-duration, high-current electrical pulses that result in a fused metallurgical bond to the substrate. The pulse microsecond duration splat transfer produces micro- and nanostructures and a very narrow heat-affected zone. The limited corrosion and hydrogen-induced cracking resistance of conventional ultrahigh strength 4340 type steel, greater than 1500-MPa yield strength, led to the development of precipitation-hardened, corrosion-resistant, ultrahigh-strength steel alloys such as Custom 465 and Ferrium S53. Additive surface repair technologies of these alloys in the heat-treated condition are very limited. Preheating requirements, distortion, heat-affected zones, and post-additive heat-treatment requirements prevent surface treatments in the heat-treated condition. This paper characterizes ESD applied to ultrahigh-strength steel with respect to the heat-affected zone and the deposit–substrate mixed zone through micro- and nanohardness measurements and through microstructural and microchemical characterization. The additive alloy was Stellite 21, a cobalt-based, high-chromium alloy capable of developing high hardness and high corrosion resistance. Results show that, properly applied, the heat-affected zone width ranged from 8 to 15 μm. Microhardness analysis revealed a drop in hardness within this zone. The weld dilution zone width in the deposit is on the order of 8 to 10 μm within the first two deposit layers. |
| Databáze: | OpenAIRE |
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