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Residual Stress Distribution in Dievar Tool Steel Bars Produced by Conventional Additive Manufacturing and Rotary
Josef Izák1, Pavel Strunz2, Olena Levytska2
1Faculty of Mechanical Engineering, Brno University of Technology, Technická 2896, 616 00 Brno, Czech Republic.
Materials (Basel, Switzerland)
|December 17, 2024
Summary
Manufacturing methods significantly impact residual stresses in Dievar steel. Rotary swaging effectively reduces these stresses and enhances microstructure and hardness in both conventionally cast and additively manufactured components.
Area of Science:
- Materials Science
- Metallurgy
- Manufacturing Engineering
Background:
- Residual stresses are critical factors influencing material failure.
- Additive manufacturing (AM) processes like selective laser melting (SLM) can introduce significant residual stresses.
- Understanding and mitigating these stresses is crucial for component integrity.
Purpose of the Study:
- To investigate the influence of manufacturing strategies on residual stress development in Dievar steel.
- To evaluate the effectiveness of hot rotary swaging as a post-processing technique for stress reduction and property enhancement.
- To compare residual stress profiles and microstructural characteristics between conventional ingot casting and SLM.
Main Methods:
- Dievar steel bars were fabricated using conventional ingot casting and selective laser melting (SLM).
- Hot rotary swaging at 900 °C was applied as a thermomechanical treatment.
- Residual stresses were quantified using neutron diffraction.
- Microstructural analysis, phase identification, precipitate characterization, and hardness testing were performed.
Main Results:
- Conventional casting resulted in low residual stresses (±200 MPa) with hardness increasing from 172 HV1 to 613 HV1 after swaging.
- SLM produced tensile surface stresses and compressive core stresses (-600 MPa) which were reduced to +200 MPa and -300 MPa respectively after swaging.
- Rotary swaging refined grain structure (3-5 µm) and increased hardness in SLM samples (560 HV1 to 606 HV1).
Conclusions:
- Manufacturing method significantly dictates residual stress distribution in Dievar steel.
- Hot rotary swaging is an effective post-processing method to reduce detrimental residual stresses in both conventional and additively manufactured components.
- Rotary swaging improves microstructural and mechanical properties, including hardness and grain refinement, alongside stress mitigation.
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