Investigation of remelting and preheating in SLM of 18Ni300 maraging steel as corrective and preventive measures for porosity reduction



One of the most critical defects in selective laser melting (SLM) is the porosity formation. Optimization of process parameters for reducing the porosity levels to lower than <1% is possible in most of the cases. Susceptibility to porosity formation can be higher for different alloys as function of chemical composition due to higher spark generation and molten pool instabilities. On the other hand, the probability of porosity formation increases in larger components due to an extended processing time. Powder recoater wear, increase in thermal load, and accumulation of particles in the processing chamber become more relevant as the processing time increases. Hence, the use of integrated monitoring and correction strategies becomes crucially important.

In this work, three different correction strategies are discussed for the correction of porosity during the SLM of 18Ni300 maraging steel. The main aim is to develop a possible correction and prevention scheme to be used within a fully monitored SLM process. The 18Ni300 maraging steel is susceptible to high levels of porosity due to the empirically observed melt-pool instabilities as well as high spark and vapor generation. The correction methods consisted of remelting of the defected layer employing different scan strategies namely “double pass,” “soft melting,” and “polishing.” As a preventive strategy, preheating at 170 °C was also evaluated. At an initial stage, all the strategies were tested throughout the part built in order to assess their general capacity in improving the part density. Surface roughness, geometrical error, and material microhardness were also evaluated to assess the impact of the strategies on the other quality aspects. The results indicate the capacity of improving the part density and reduce the part roughness effectively.


Additive manufacturing Porosity Defect correction Defect prevention Surface roughness Geometrical error Microhardness 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Gong H, Rafi K, Gu H, Starr T, Stucker B (2014) Analysis of defect generation in Ti-6Al-4V parts made using powder bed fusion additive manufacturing processes. Addit Manuf 1:87–98. doi: 10.1016/j.addma.2014.08.002 CrossRefGoogle Scholar
  2. 2.
    Abdelrahman M, Reutzel EW, Nassar AR, Starr TL (2017) Flaw detection in powder bed fusion using optical imaging. Addit Manuf 15:1–11. doi: 10.1016/j.addma.2017.02.001 CrossRefGoogle Scholar
  3. 3.
    Neef A, Seyda V, Herzog D, Emmelmann C, Schönleber M, Kogel-Hollacher M (2014) Low coherence interferometry in selective laser melting. Phys Procedia 56:82–89. doi: 10.1016/j.phpro.2014.08.100 CrossRefGoogle Scholar
  4. 4.
    Everton SK, Hirsch M, Stravroulakis P, Leach RK, Clare AT (2016) Review of in-situ process monitoring and in-situ metrology for metal additive manufacturing. Mater Des 95:431–445. doi: 10.1016/j.matdes.2016.01.099 CrossRefGoogle Scholar
  5. 5.
    Grasso M, Colosimo BM (2017) Process defects and in situ monitoring methods in metal powder bed fusion: a review. Meas Sci Technol 28:44005. doi: 10.1088/1361-6501/aa5c4f CrossRefGoogle Scholar
  6. 6.
    Kasperovich G, Haubrich J, Gussone J, Requena G (2016) Correlation between porosity and processing parameters in TiAl6V4 produced by selective laser melting. Mater Des 105:160–170. doi: 10.1016/j.matdes.2016.05.070 CrossRefGoogle Scholar
  7. 7.
    Kamath C, El-dasher B, Gallegos GF, King WE, Sisto A (2014) Density of additively-manufactured, 316L SS parts using laser powder-bed fusion at powers up to 400 W. Int J Adv Manuf Technol:65–78. doi: 10.1007/s00170-014-5954-9
  8. 8.
    Aboulkhair NT, Everitt NM, Ashcroft I, Tuck C (2014) Reducing porosity in AlSi10Mg parts processed by selective laser melting. Addit Manuf 1:77–86. doi: 10.1016/j.addma.2014.08.001 CrossRefGoogle Scholar
  9. 9.
    Senthilkumaran K, Pandey PM, Rao PVM (2009) Influence of building strategies on the accuracy of parts in selective laser sintering. Mater Des 30:2946–2954. doi: 10.1016/j.matdes.2009.01.009 CrossRefGoogle Scholar
  10. 10.
    Bouwer S (2016) Leveraging geometry optimization tools to reduce component weight, development cost, and design schedule Philadelphia, PA. AHS Int 72nd Annu Forum 1–20Google Scholar
  11. 11.
    Cloots M, Spierings AB, Wegener K (2013) Assessing new support minimizing strategies for the additive manufacturing technology SLM. Int Solid Free Fabr Symp An Addit Manuf Conf August 12-14 2013:131–9. doi:10.1017/CBO9781107415324.004Google Scholar
  12. 12.
    Calignano F (2014) Design optimization of supports for overhanging structures in aluminum and titanium alloys by selective laser melting. Mater Des 64:203–213. doi: 10.1016/j.matdes.2014.07.043 CrossRefGoogle Scholar
  13. 13.
    Yadroitsev I, Krakhmalev P, Yadroitsava I, Johansson S, Smurov I (2013) Energy input effect on morphology and microstructure of selective laser melting single track from metallic powder. J Mater Process Technol 213:606–613. doi: 10.1016/j.jmatprotec.2012.11.014 CrossRefGoogle Scholar
  14. 14.
    Buchbinder D, Meiners W, Pirch N, Wissenbach K, Schrage J (2014) Investigation on reducing distortion by preheating during manufacture of aluminum components using selective laser melting. J Laser Appl 26:12004. doi: 10.2351/1.4828755 CrossRefGoogle Scholar
  15. 15.
    Zhou S, Huang Y, Zeng X, Hu Q (2008) Microstructure characteristics of Ni-based WC composite coatings by laser induction hybrid rapid cladding. Mater Sci Eng A 480:564–572. doi: 10.1016/j.msea.2007.07.058 CrossRefGoogle Scholar
  16. 16.
    Zhou S, Zeng X, Hu Q, Huang Y (2008) Analysis of crack behavior for Ni-based WC composite coatings by laser cladding and crack-free realization. Appl Surf Sci 255:1646–1653. doi: 10.1016/j.apsusc.2008.04.003 CrossRefGoogle Scholar
  17. 17.
    Zarini S, Previtali B, Vedani M, Rovatti L (2014) Cracks susceptibility elimination in fiber laser cladding of Ni-based alloy with addition of tungsten carbides. Proc. ASME 2014 12th Bienn. Conf. Eng. Syst. Des. Anal. ESDA2014, p. ESDA2014–20623Google Scholar
  18. 18.
    Yasa E, Kruth JP (2010) Investigation of laser and process parameters for selective laser erosion. Precis Eng 34:101–112. doi: 10.1016/j.precisioneng.2009.04.001 CrossRefGoogle Scholar
  19. 19.
    MC Machinery Systems Inc (n.d.) Lumex Avance 25 (accessed March 2, 2017)
  20. 20.
    Sodick Co Ltd (n.d.) OPM350L (accessed March 2, 2017)
  21. 21.
    Kruth J-P, Yasa E, Deckers J (2008) Roughness improvement in selective laser melting. Proc 3rd Int Conf Polym Mould Innov 170–83.Google Scholar
  22. 22.
    Vaithilingam J, Goodridge RD, Hague RJM, Christie SDR, Edmondson S (2016) The effect of laser remelting on the surface chemistry of Ti6al4V components fabricated by selective laser melting. J Mater Process Technol 232:1–8. doi: 10.1016/j.jmatprotec.2016.01.022 CrossRefGoogle Scholar
  23. 23.
    Kruth J, Badrossamay M, Yasa E, Deckers J, Thijs L, Van Humbeeck J (2010) Part and material properties in selective laser melting of metals. 16th Int Symp Electromachining 1–12Google Scholar
  24. 24.
    Yasa E, Kempen K, Kruth J (2010) Microstructure and mechanical properties of Maraging Steel 300 after selective laser melting. Proc 21st Int Solid Free Fabr Symp 383–96Google Scholar
  25. 25.
    Jägle EA, Choi P-P, Van Humbeeck J, Raabe D (2014) Precipitation and austenite reversion behavior of a maraging steel produced by selective laser melting. J Mater Res 29:2072. doi: 10.1557/jmr.2014.204 CrossRefGoogle Scholar
  26. 26.
    Demir AG, Colombo P, Previtali B (2017) From pulsed to continuous wave emission in SLM with contemporary fiber laser sources: effect of temporal and spatial pulse overlap in part quality. Int J Adv Manuf Technol 91:2701–2714. doi: 10.1007/s00170-016-9948-7
  27. 27.
    Zhou X, Liu X, Zhang D, Shen Z, Liu W (2015) Balling phenomena in selective laser melted tungsten. J Mater Process Technol 222:33–42. doi: 10.1016/j.jmatprotec.2015.02.032 CrossRefGoogle Scholar
  28. 28.
    Lamikiz A, Sánchez JA, López de Lacalle LN, Arana JL (2007) Laser polishing of parts built up by selective laser sintering. Int J Mach Tools Manuf 47:2040–2050. doi: 10.1016/j.ijmachtools.2007.01.013 CrossRefGoogle Scholar
  29. 29.
    De Giorgi C, Furlan V, Demir AG, Tallarita E, Candiani G, Previtali B (2017) Laser micropolishing of AISI 304 stainless steel surfaces for cleanability and bacteria removal capability. Appl Surf Sci 406:199–211. doi: 10.1016/j.apsusc.2017.02.083 CrossRefGoogle Scholar
  30. 30.
    Qiu C, Panwisawas C, Ward M, Basoalto HC, Brooks JW, Attallah MM (2015) On the role of melt flow into the surface structure and porosity development during selective laser melting. Acta Mater 96:72–79. doi: 10.1016/j.actamat.2015.06.004 CrossRefGoogle Scholar
  31. 31.
    Casati R, Lemke JN, Tuissi A, Vedani M (2016) Aging behaviour and mechanical performance of 18-Ni 300 steel processed by selective laser melting. Metals (Basel) 6. doi: 10.3390/met6090218

Copyright information

© Springer-Verlag London Ltd. 2017

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringPolitecnico di MilanoMilanItaly

Personalised recommendations