Title : Processability of AISI-H13 hot work tool steel processed via additive manufacturing
Abstract:
Additive manufacturing offers the advantage of producing intricate parts more efficiently compared to traditional methods, resulting in cost savings and improved product quality. One promising application involves creating molds and dies with conformal cooling for injection molding, die casting, and forging. AISI H13 tool steel is commonly employed in these scenarios due to its exceptional properties such as high hardness at elevated temperature, good wear resistance, and commendable toughness. In this study, the primary focus was on examining the processability of AISI H13 tool steel using powder bed fusion with laser beam (PBF-LB), while also conducting a microstructural analysis. The experimental parameters, including laser power (ranging from 97 to 216 W) and scan speed (ranging from 300 to 700 mm/s), were intentionally varied to assess their impact on part consolidation, common defects, solidification structure, microstructure, and Vickers hardness. Throughout the explored range of processing parameters, the microstructural features were found to be largely consistent, characterized by a predominantly cellular solidification structure consisting of martensite with retained austenite content ranging from 19.8% to 25.9%. The cellular/dendritic solidification structure exhibited segregation of elements such as C, Cr, and V towards the cell walls. The thermal cycle led to the formation of alternating layers of heat-affected zones, exhibiting some variations in hardness and microstructure. The presence of retained austenite was found to be associated with the solidification structure and displayed a preferential orientation aligned with the {001}//build direction. Density and porosity maps were obtained through helium gas pycnometry and light optical microscopy, respectively. These, along with the evaluation of linear crack density, were employed to identify appropriate processing parameters for H13 tool steel. Additionally, measurements of thermal diffusivity, thermal conductivity, and thermal capacity were conducted to determine dimensionless processing parameters, which were then compared to values reported in the existing literature.
Audience Take Away Notes:
- Understand the process window of H13 steel under AM PBF-LB
- This research presents a workflow to study process parameters and metallurgical characterization for alloys processed via AM PBF-LB
- Comparison between dimensionless parameters and volumetric energy density
