Process Evaluation of AISI 4340 Steel Manufactured by Laser Powder Bed Fusion

Jelis, Elias; Hespos, Michael R.; Ravindra, Nuggehalli M.

doi:10.1007/s11665-017-2989-8

Cited by 25 publications

(4 citation statements)

References 9 publications

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“…A number of low-alloy steels have already been successfully processed with LB-PBF, including HY100 [9], AF9628 [10], 4130 [11], 4140 [12–14] and 4340 [1516]. These studies indicate that build plate preheating is advised to successfully minimise cold cracking within the as-built components.…”

Section: Introductionmentioning

confidence: 99%

Laser-based powder bed fusion of non-weldable low-alloy steels

2021

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This study focuses on the processability of four low-alloy steels (AISI 4130, 4140, 4340 and 8620) via laser-based powder bed fusion (LB-PBF). In the as-built condition, the alloys consisted of tempered martensite that was the result of an intrinsic heat treatment (IHT) during LB-PBF. In terms of defects, a distinct transition in porosity was observed that correlated to the volumetric energy density (VED). At low VED, specimens contained a lack of fusion porosity, while at high VED, they contained keyhole porosity. Additionally, cold cracking was observed in 4140 and 4340 specimens produced at low/intermediate VEDs. This cracking could be mitigated by increasing the VED or laser power, as both enhance the IHT. This enhanced IHT lowered the material hardness below specific thresholds (<500HV 4340 and <460 4140), increasing ductility and allowing the specimens to avoid cracking. From these findings, crack-free, high-density (>99.8%) low-alloy steel specimens were produced without the requirement of build plate preheating.

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Section: Introductionmentioning

confidence: 99%

Laser-based powder bed fusion of non-weldable low-alloy steels

2021

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“…However, other recent works already showed the possibility to manufacture low alloy steels (~ 0.5 C wt. %) [6,[16][17][18][19][20][21]. The present study thus aims to provide the basis for understanding the processability of low alloy tool steel grade AISI S2.…”

Section: Development and Processability Of Aisi S2 Tool Steel By Lase...mentioning

confidence: 99%

Development and processability of AISI S2 tool steel by laser powder bed fusion

Saggionetto

2023

Materials Research Proceedings

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Abstract. Nowadays, the advantages of Laser Powder Bed Fusion (LPBF) technology attract both industry and researchers. Indeed, it is possible to build up complex geometrical parts with higher mechanical properties than those obtained by conventional methods. However, LPBF involves complex phenomena due to the high heating and cooling rates that lead to out-of-equilibrium conditions. For this reason, few metal alloys are easily processable up to now. Nevertheless, research on new steels by LPBF has been growing in recent years, in particular, regarding the development of tool steels. This work thus focuses on the development of the tool steel AISI S2 by LPBF. The process map has been investigated by varying the laser power from 100 to 250 W and the scan speed from 400 to 2000 mm/s. By combining surface analysis by means of profilometer observations, density measurements by pycnometry, defects characterization and quantification and investigations on the melt pool morphology, the best process window is selected to have fully dense, defect-free parts. Furthermore, this study allows to have comprehensive insights on the effect of the parameters on the type of defects generated during the manufacturing.

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“…Additionally, there are generic issues during PBF-LB (e.g. keyholes pores and lack of fusion defects) that can lead to a reduction in performance when compared to conventionally produced material and induce anisotropic behaviour [5][6][7]. Overall, these issues have put into question the viability of martensitic low-alloy steel when using PBF-LB.…”

Section: Introductionmentioning

confidence: 99%

“…In order to adopt these alloys for PBF-LB, detailed process development is required in combination with mechanical property testing. To date, limited data on this subject is available in the literature, with process development of martensitic low-alloy steel primarily involving single-track experiments [8][9][10] and the production of specimens at specific sets of processing parameters [6,7,11,12]. An important parameter that has yet to be examined in adequate detail is the build plate preheating temperature (BPT), which has improved the processing of carbon-containing tool steels during PBF-LB [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Development of powder bed fusion – laser beam process for AISI 4140, 4340 and 8620 low-alloy steel

2022

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This study focuses on process development and mechanical property evaluation of AISI 4140, 4340 and 8620 low-alloy steel produced by powder bed fusionlaser beam (PBF-LB). Process development found that increasing the build plate preheating temperature to 180°C improved processability, as it mitigated lack of fusion and cold cracking defects. Subsequent mechanical testing found that the low-alloy steels achieved a high ultimate tensile strength

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Process Evaluation of AISI 4340 Steel Manufactured by Laser Powder Bed Fusion

Cited by 25 publications

References 9 publications

Laser-based powder bed fusion of non-weldable low-alloy steels

Laser-based powder bed fusion of non-weldable low-alloy steels

Development and processability of AISI S2 tool steel by laser powder bed fusion

Development of powder bed fusion – laser beam process for AISI 4140, 4340 and 8620 low-alloy steel

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