A Comparative Study on the Microstructures and Mechanical Properties of Two Kinds of Iron-Based Alloys by WAAM

Abstract

In order to adapt to the high temperature and heavy load process environment of large forgings, a novel die with “fist-like” structure is designed. The “fist-like” die mainly consists of “skin” layer, “bone” layer and matrix. To obtain the material with good supportability and good bonding strength with the “skin” layer, iron-based alloys RMD248 and CN72 were selected to make the “bone” layer, and the properties were compared. In this paper, the “bone” layer and the “skin” layer (CHN327) were surfaced on 5CrNiMo matrix by wire arc additive manufacture (WAAM). Then, cyclic heating to 500 °C and thermal compression with a maximum deformation of 30% were adapted to test the high temperature mechanical properties. The microstructure changes before and after thermal cycles and compressions were observed by optical microscopy (OM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and scanning electron microscopy (SEM). The results show that CN72 has more carbides than RMD248 at the joint surface, which makes it easy to form brittle fracture at the joint. Mechanical properties were tested by using microhardness machine. Meanwhile, hot tensile tests were performed to study bonding strength between the “skin” layer and the “bone” layer. The results show that the RMD248 has stable microhardness distribution while the microhardness of CN72 decreases with the distance from the interface. And the ultimate tensile strength between CN72 and CHN327 is higher than RMD248 in the temperature range of 400–450 °C. It can be inferred that CN72 has higher inter-layer wear resistance and RMD248 has more stable high temperature performance.

Keywords

iron-based alloy / wire arc additive manufacture / die / microstructure / mechanical properties

References

[1] Altan T, Lilly B, Yen YC. Manufacturing of Dies and Molds[J]. Cirp. Ann-Manuf. Technol., 2001, 50(2): 405-423.

[2] Lu S, Zhou J, Zhang J S. Optimization of Welding Thickness on Casting-Steel Surface for Production of Forging Die[J]. Int. J. Adv. Manuf. Technol., 2015, 76(5–8): 1411-1419.

[3] Shen L, Zhou J, Ma X, et al. Microstructure and Mechanical Properties of Hot Forging Die Manufactured by Bimetal-Layer Surfacing Technology[J]. J. Mater. Process. Technol., 2017, 239: 147-159.

[4] Wang X H, Han F, Qu S Y, et al. Microstructure of the Fe-Based Hardfacing Layers Reinforced by TiC-VC-Mo₂C Particles[J]. Surf. Coat. Technol., 2008, 202(8): 1502-1509.

[5] Zhang J S, Zhou J, Tao Y P, et al. The Microstructure and Properties Change of Dies Manufactured by Bimetal-Gradient-Layer Surfacing Technology[J]. Int. J. Adv. Manuf. Technol., 2015, 80(9–12): 1807-1814.

[6] Xia Y F, Jin L, Cheng Q, et al. A Comparative Study on the Microstructures and Mechanical Properties Between Surfacing Nickel-Based Superalloy and Surfacing Cobalt-Based Superalloy[J]. Mater. Res. Express, 2019, 6(9): 12

[7] Zhou Y F, Yang Y L, Jiang Y W, et al. Fe-24 wt%Cr-4.1 wt%C Hardfacing Alloy: Microstructure and Carbide Refinement Mechanisms With Ceria Additive[J]. Mater. Charact., 2012, 72: 77-86.

[8] Yang K, Jiang Y F, Bao Y F. Effect of Titanium Content on Microstructure and Wear Resistance of Hardfacing Alloy[J]. J. Wuhan Univ. Technol.-Mat. Sci. Edit., 2018, 33(3): 669-673.

[9] Masaylo D V, Orlov A, Razumov N G, et al. Laser Cladding of Heat-Resistant Iron Based Alloy[J]. Key Engineering Materials, 2019, 822: 520-525.

[10] Shen L, Zhou J, Xiong Y B, et al. Analysis of Service Condition of Large Hot Forging Die and Refabrication of Die by Bimetal-Layer Weld Surfacing Technology with a Cobalt-Based Superalloy and a Ferrous Alloy[J]. J. Manuf. Process., 2018, 31: 731-743.

[11] Zhang J S, Zhou J, Wang Q Y, et al. Process Planning of Automatic Wire Arc Additive Remanufacturing for Hot Forging Die[J]. Int. J. Adv. Manuf. Technol., 2020, 109(5–6): 1613-1623.

[12] Wang X L, Wang A M, Li Y B. A Sequential Path-Planning Methodology for Wire and Arc Additive Manufacturing Based on a Water-Pouring Rule[J]. Int. J. Adv. Manuf. Technol., 2019, 103(9–12): 3813-3830.

[13] Shen C, Pan Z X, Ma Y, et al. Fabrication of Iron-Rich Fe-Al Intermetallics Using the Wire-Arc Additive Manufacturing Process[J]. Addit. Manuf., 2015, 7: 20-26.

[14] Azimi G, Shamanian M. Effects of Silicon Content on the Microstructure and Corrosion Behavior of Fe-Cr-C Hardfacing Alloys[J]. J. Alloy. Compd., 2010, 505(2): 598-603.

[15] Gao F, Zhou J, Zhou J F, et al. Microstructure and Properties of Surfacing Layers of Dies Manufactured by Bimetal-Gradient-Layer Surfacing Technology before and after Service[J]. Int. J. Adv. Manuf. Technol., 2016, 88(5–8): 1-9.

[16] Northover P, Crossley A, Grazioli C, et al. A Multitechnique Study of Archeological Bronzes[J]. Surf. Interface Anal., 2008, 40(3–4): 464-468.

[17] Adachi S. The Handbook on Optical Constants of Metals: In Tables and Figures[M], 2012 Singapore: World Scientific.

[18] Liu X B, Yu G, Guo J, et al. Research on Laser Welding of Cast Ni-Based Superalloy K418 Turbo Disk and Alloy Steel 42CrMo Shaft[J]. J. Alloy. Compd., 2008, 453(1–2): 371-378.

[19] Maugis P, Kandaskalov D. Revisiting the Pressure Effect on Carbon Migration in Iron[J]. Mater. Lett., 2020, 270: 437-449.

[20] Liu J, Chen W P. Microstructure, Mechanical Properties and Corrosion Behavior of an Fe-10Cr-2.7B-5.5Al-13Mn Alloy Prepared by Spark Plasma Sintering[J]. J. Alloy. Compd., 2018, 741: 348-359.

[21] Bonny G, Domain C, Castin N, et al. The Impact of Alloying Elements on the Precipitation Stability and Kinetics in Iron Based Alloys: An Atomistic Study[J]. Comput. Mater. Sci., 2019, 161: 309-320.

[22] Yuksel N, Sahin S. Wear Behavior-Hardness-Microstructure Relation of Fe-Cr-C and Fe-Cr-C-B Based Hardfacing Alloys[J]. Mater. Des., 2014, 58: 491-498.

[23] Abbasi E, Rainforth W M. Microstructural Evolution of Nb-V-Mo and V Containing Trip-Assisted Steels During Thermomechanical Processing[J]. J. Mater. Sci. Technol., 2017, 33(4): 311-320.

[24] Aguilar-Sierra S M, Giraldo C P S, Aristizabal-Sierra R E. Microstructural Transformations in Dissimilar Welds between Austenitic Stainless Steel and Ferritic Stainless Steel[J]. Soldagem Insp., 2015, 20(1): 59-67.

[25] Joshy S, Jayadevan K R, Ramesh A, et al. Microstructural Evolution and Microhardness Response of H11 Hot Forging Dies[J]. World Journal of Engineering, 2019, 16(5): 573-581.

[26] Yang G X, Xu Y F, Jiang L, et al. High Temperature Tensile Properties and Fracture Behavior of Cast Nickel-Base K445 Superalloy[J]. Prog. Nat. Sci., 2011, 21(5): 418-425.

[27] Jiang D W, Zheng L J, Zhou L, et al. High Temperature Tensile Properties of Directionally Solidified Ni-43Ti-4Al-2Nb-2Hf Alloy[J]. Rare Metals, 2012, 31(4): 328-331.