**Thermal Di**ff**usivity Measurement of Laser-Deposited AISI H13 Tool Steel and Impact on Cooling Performance of Hot Stamping Tools**

#### **Jon Iñaki Arrizubieta 1,\*, Magdalena Cortina 1, Arantza Mendioroz 2, Agustín Salazar 2 and Aitzol Lamikiz 1**


Received: 19 December 2019; Accepted: 15 January 2020; Published: 20 January 2020

**Abstract:** Additive manufacturing is a technology that enables the repair and coating of high-added-value parts. In applications such as hot stamping, the thermal behavior of the material is essential to ensure the proper operation of the manufactured part. Therefore, the effective thermal diffusivity of the material needs to be evaluated. In the present work, the thermal diffusivity of laser-deposited AISI H13 is measured experimentally using flash and lock-in thermography. Because of the fast cooling rate that characterizes the additive process and the associated grain refinement, the effective thermal diffusivity of the laser-deposited AISI H13 is approximately 15% lower than the reference value of the cast AISI H13. Despite the directional nature of the process, the laser-deposited material's thermal diffusivity behavior is found to be isotropic. The paper also presents a case study that illustrates the impact of considering the effective thermal conductivity of the deposited material on the hot stamping process.

**Keywords:** DED; laser; additive manufacturing; thermal conductivity; thermal diffusivity; thermal modeling; hot stamping; AISI H13
