Cast Bonding of Cast Irons to Ferritic Stainless Steel

Abstract

Composite metal products consisting of two different alloys can be prepared by a few methods. Cast bonding is one of these methods. The bond between the two materials forms primarily in the solid state by diffusion, after casting of a cladding alloy on to the preheated surface of a substrate. In this work, a ferritic stainless steel was used as the substrate, and, gray iron or nodular iron as the cast alloy. It was found that these two alloys can be successfully joined, and under specific casting parameters, a very strong bond develops between the two alloys. Bond strength was found to be greater than that of gray iron. Microstructural zones on both sides of the bond were studied. It was found that diffusion of chromium into iron and diffusion of carbon into steel is significant in bonding. Chemical composition changes due to diffusion was studied by EDS. Fe-Cr-Mn carbides were formed at the bond during the casting. These carbides were largely eliminated by a subsequent high temperature heat treatment.

Interfacial reactions in white iron/steel composites

“…Interfacial layers have also been observed in other joints between dissimilar alloys produced by techniques such as vacuum casting (Huggett et al, 2005), cast bonding (Cingi et al, 2010) and hard-facing (Chang et al, 2009). For example, the latter workers found that fusion bonding of a 40% chromium white iron to an ASTM A36 steel plate resulted in the formation of a planar interfacial layer of alpha phase layer via epitaxial solidification.…”

“…In this method a melt of wear resistant alloy is cast onto a preheated solid steel substrate in a foundry. Cingi et al described a variant of this process in which cast iron was bonded to ferritic stainless steel (Cingi et al, 2010). 'Cast bonding' may also be described as the 'hard top' process (Chattopadhyay, 2001).…”

Manufacturing Methods of Alloy Layers on Casting Surfaces

“…Therefore, this technology can be significantly competitive for the commonly used technologies of surfacing by welding and thermal spraying because, in addition to its economic advantages, it does not generate opportunities for the development of cracks in the heat-affected zone that may arise as a result of making the layer by using the welding method. In general, the technology of cast bimetals containing a working layer and a base part is carried out based on two systems; i.e., liquid-liquid [1,2] and liquid-solid [3][4][5][6][7][8][9][10][11][12][13][14][15][16]. An example of the former is a technology in which two independent gating systems are made, which guarantees a two-stage filling of the sand mold cavity.…”

“…The basis technology of layered castings made in a liquid-solid system is the so-called method of mold cavity preparation. In this manufacturing method, the element enriching the surface of the casting is placed in the mold in the form of a granular [3][4][5][6][7][8][9] or monolithic [10][11][12][13][14][15][16] insert directly before the molten metal is poured. Therefore, this paper presents possibilities of using a Cr-base alloy as a granular insert and high-chromium and chromium-nickel alloy steels as monolithic inserts.…”

Characterization of Bimetallic Castings with an Austenitic Working Surface Layer and an Unalloyed Cast Steel Base

“…In general, the technology of bimetallic castings containing a working layer and a base part is carried out based on two fundamental methods, i.e., the liquid-liquid (Ref 1-3) and liquid-solid (Ref [4][5][6][7][8][9][10][11][12][13][14][15][16][17] configuration. An example of the former is a technology in which two independent gating systems are made that guarantee two-stage filling of the sand mold cavity.…”