Production and Characterization of Austenitic Stainless Steel Cast Parts Reinforced with WC Particles Fabricated by Ex Situ Technique

Abstract

In this work, austenitic stainless steel specimens were locally reinforced with WC particles. The reinforcements were fabricated via an ex situ technique based on powder technology. Mixtures of WC, Fe, and M0101 binder were cold-pressed to obtain powder compacts. After debinding and sintering, the porous WC–Fe inserts were fixed in a mold cavity, where they reacted with liquid metal. Microstructural analysis was conducted for characterization of the phases constituting the produced reinforcement zone and the bonding interface. The results revealed that the reinforcement is a graded material with compositional and microstructural gradients throughout its thickness. The zone nearest to the surface has a ferrous matrix with homogeneously distributed WC particles and (Fe,W,Cr)6C and (Fe,W,Cr)3C carbides, formed from the liquid metal reaction with the insert. This precipitation leads to austenite destabilization, which transforms into martensite during cooling. A vast dissolution of the WC particles occurred in the inner zones, resulting in more intense carbides formation. Cr-rich carbides ((Fe,Cr,W)7C3, and (Fe,Cr,W)23C6) formed in the interdendritic regions of austenite; this zone is characterized by coarse dendrites of austenite and a multi-phase interdendritic network composed of carbides. An interface free of discontinuities and porosities indicates good bonding of the reinforcement zone to stainless steel.

Cast Austenitic Stainless Steel Reinforced with WC Fabricated by Ex Situ Technique

“…The specimens were produced by casting as described in detail in our recent work [17]. Porous Fe-WC preforms, composed of 28 vol.% WC (D 50 = 107 µm), 42 vol.% Fe (D 50 = 8 µm), and 30 vol.% M0101 binder (D 50 = 398 µm), with dimensions of 31 mm × 12 mm × 9 mm, were prepared using powder technology.…”

“…The electrolytic etching revealed small grains of ferrite in the matrix of austenite (γ). Our previous study reports in detail the characterization of these phases by SEM/EDS, electron backscatter diffraction (EBSD), and X-ray diffraction (XRD) techniques [17].…”

“…Several studies have been carried out to investigate the methodologies for producing locally reinforced steel parts with tungsten carbide (WC) particles [9][10][11][12][13][14][15][16]. More recently, austenitic stainless steel castings locally reinforced with Fe-WC inserts by employing an ex situ technique based on powder metallurgy technology were also successfully produced, and detailed microstructural characterization of phases formed in the reinforcement zone was performed [17]. This study aims to expand the knowledge about the behavior of locally reinforced stainless steel by analyzing the mechanical properties, including that of the phases formed.…”

Investigation of Manufacturability of WC Particle Reinforced Steels by Powder Metallurgy Method

“…Alloys such as nickel, molybdenum, vanadium are some of the alloying elements added [6]. Steels contain carbon, silicon phosphorus and small amounts of aluminum elements [7][8][9]. While these elements impart hardness to steels, elements such as nickel, vanadium, titanium and manganese give stainless steels the ability to be shaped.…”