Progress on Additive Manufacturing of Maraging Steel

Fig. 1. Traditional methods as well as working principle and typical characteristics of LPBF AM of maraging steel. (a) Schematic of traditional preparation methods; (b) schematic of LPBF process parameters and microstructure of maraging steel by AM; (c) characteristic temperature change during formation of maraging steel; (d) in-situ heat treatment effect of AM and schematic of maraging phase transformation; (e) effects of defects, in-situ heat treatment, and post-treatment on mechanical properties of maraging steel by AM

Download full size

Fig. 2. Effects of LPBF and its post-treatment process on microstructure, relative density and surface roughness of maraging steel. (a) Effect of LPBF laser energy density on relative density, Vickers hardness, and surface roughness of maraging steel^[31-32]; (b) microstructure of 18Ni300 maraging steel by DED AM; (c) enlarged microstructure; (d) industrial computed tomography (CT) result of maraging steel at as-fabricated state by AM; (e) industrial CT at hot isostatic pressing state^[32]

Download full size

Fig. 3. Mechanical properties of FeNi based maraging steels by AM and variation trends ^{[5,11,14-15,31,33-37,39-40,43-59]}. (a) Tensile elongation at break; (b) tensile strength

Download full size

Fig. 4. Schematics of AM of heterostructural steel and functionally graded material. (a) AM maraging steel/Damascus-like steel and thermal cycling temperature curve^[11]; (b) AM heterostructure maraging steel and microhardness distribution^[58]; (c) forming method and interfacial heat-affected zone of functionally graded material by AM^{[48,55,60-62]}

Download full size

Fig. 5. Microstructure and three-dimensional atom probe tomography (3D-APT ) analysis of heterostructural Fe-19Ni-5Ti maraging steel by AM as well as effects of graded materials and composite particle reinforcement phase on comprehensive properties. (a) Optical micrographs and 3D-APT as well as magnified view of precipitated phase and composition concentration distribution^[11]; (b) mechanical properties of graded materials by AM^{[48,55,60-62]}; (c) effects of composite particle reinforcement phase on tensile strength and elongation of maraging steel by AM^[32,36,63]; (d) effects of SiC addition on wear rate (K_c) and corrosion current density (I_corr) in maraging steel by AM^[32]

Download full size

Fig. 6. Applications of AM maraging steel in conformal cooling die and laser cladding repair technology. (a) Three-dimensional design of mold with spiral conformal cooling channels and LPBF fabricated 18Ni300 maraging steel mold (after mechanical finishing)^[65]; (b) effects of channel cavity spacing and waterway spacing on cooling time and surface temperature difference of conformal cooling die^[66]; (c) cross sections of erosion zone and repaired zone of laser cladding repaired and alloy strengthened 2Cr13 martensitic stainless steel blade^[67]

Download full size

Table 1. Yield stress, ultimate tensile strength and elongation of maraging steel at different states by each AM process

View table

Table 1. Yield stress, ultimate tensile strength and elongation of maraging steel at different states by each AM process

Steel	Process	State	YS /MPa	UTS /MPa	El	Research institution	Ref.
18Ni300	LPBF	As-fabricated Heat-treated	1214 1998±32	1290±114 2217±73	13.3%±1.9% 1.60%±0.26%	Katholieke Universiteit, Belgium	[35]
TiC/AISI420	LPBF	As-fabricated	-	1218.0-1452.5	7.43%-8.65%	Huazhong University of Science and Technology, China	[36]
Low Ti-18Ni300	LPBF	As-fabricated	988.0±177.3	1196.3±4.6	15.1%±1.0%	University of New Brunswick，Canada	[37]
High Ti-18Ni300	LPBF	As-fabricated	1113.0±11.0	1217.7±11.7	15.39%±1.20%	University of New Brunswick，Canada	[37]
19Ni3Mo1.5Ti	LPBF	Heat-treated	1730±9	1892±7	11.5%±0.1%	University of Texas at El Paso，USA	[38]
18Ni300	DMLS	As-fabricated Heat-treated	1050±100 1990±100	1057-1174 1971-2006	15.7% 6%-7%	University of Limerick, Ireland	[15]
18Ni300	LPBF	As-fabricated	1126±31	1221-1222	12.9%-14.6%	University of New Brunswick，Canada	[39]
AISI 420	DED	As-fabricated Heat-treated	517±37 535±31	1208±116 1670±202	16.5%±2.1% 15.4%±1.1%	University of Windsor，Canada	[40]
Fe19Ni5Ti	DED	As-fabricated	-	1300	>10%	Fraunhofer Institute, Germany	[11]
18Ni300	DED	As-fabricated Heat-treated	-	959.2±20.2 1561.7±16.5	0.8%-1.6% 0.06%-0.12%	Harbin Institute of Technology，China	[41]
C300	Wrought	Solution treated Aged	850±20 2050	1050±10 2100	18%±2% 10.0%±1.5%	Chinese Academy of Sciences，China	[42]

Table 2. Tensile mechanical properties of typical mold steel along laser scanning direction (SD), building direction (BD) or at different scanning speed conditions

View table

Table 2. Tensile mechanical properties of typical mold steel along laser scanning direction (SD), building direction (BD) or at different scanning speed conditions

Steel	Condition	YS /MPa	UTS /MPa	El	Hardness /HV	Ref.
FeNiTi	As-fabricated-SD	800±100	1100±100	8%±1%	-	[11]
FeNiTi	As-fabricated-BD	800±100	1050±100	4%±1%	-	[11]
5CrNi4Mo	As-fabricated-SD	-	1576	5.6%	-	[4]
5CrNi4Mo	As-fabricated-BD	-	1240	4.0%	-	[4]
5CrNi4Mo	Heat-treated-SD	-	1682	9.7%	-	[4]
5CrNi4Mo	Heat-treated-BD	-	<1350	<9%	-	[4]
316L	As-fabricated-SD	550	665	53.2%	-	[30]
316L	As-fabricated-BD	520	575	71.9%	-	[30]
H13	v＝200 mm/s	1342	1704	1.55%	585	[50]
H13	v＝400 mm/s	1167	1321	0.35%	516	[50]
H13	v＝800 mm/s	1133	1227	0.30%	469	[50]