Alloy Cast Irons

Abstract

Alloy cast irons are considered to be those casting alloys based on the iron-carbon-silicon system that contain one or more alloying elements intentionally added to enhance one or more useful properties. Alloy cast irons can be classified as white cast irons, corrosion-resistant cast irons, and heat-resistant cast irons. This article discusses abrasion-resistant chilled and white irons, high-alloy corrosion-resistant irons, and medium-alloy and high-alloy heat-resistant gray and ductile irons. The article outlines in a list the approximate ranges of alloy content for various types of alloy cast irons. The article explains the effects of alloying elements and the effects of inoculants. In most cast irons, it is the interaction among alloying elements that has the greatest effect on properties. Inoculants other than appropriate graphitizing or nodularizing agents are used rarely, if ever, in high-alloy corrosion-resistant or heat-resistant irons.

A Preliminary Study of New Experimental Low-Cost Fe–P-Based and Mn–Fe–P-Based Brazing Filler Metals for Brazing of Non-Alloy and Low-Alloy Steels

“…Due to the intermetallic phases in the microstructure, the HRC values are determined comparatively from the table for Cr-alloyed white cast iron [47]. The values are approximate because the HV→HRC converters are different for the different materials [47,48].…”

Preliminary Study of New Low-Temperature Hard Abrasion Resistant Fe-P and Fe-P-X (X = C or/and B) Casting Alloys

“…For iron-based alloys, these properties reach the highest values in white cast irons. This is due to the high content of carbon and thus carbides in their microstructure [ 1 ]. Due to their brittleness, they are suitable for parts whose surface is exposed to small pieces of hard materials with low dynamic stresses.…”

“…The chemical composition of white cast irons causes white fracture either over the entire thickness of the casting or in the surface area of thick-walled castings (from 10 to several 10 s of millimetres). The chemical compositions of various standardised white cast irons are in the following ranges (wt%): C = 2.0–3.7, Si ≤ 2.2, Mn ≤ 2, Cr ≤ 30, Mo ≤ 3.5, Ni ≤ 7, P ≤ 0.3 [ 1 , 2 , 3 ]. For example, the initial chemical compositions of malleable cast iron and unalloyed white cast iron are the same.…”

“…Casting in a mould increases the hardness of the alloy by at least 50 HB (60 HV, 3 HRC) [ 2 ]. After heat treatment, which removes high-temperature products of austenitic transformation from the microstructure, the hardness values of alloyed white cast irons typically reach 700–790 HB (800–950 HV, 62–67 HRC) [ 1 ] or at least 600 HB (660 HV, 56 HRC) for the first stage and 650 HB (715 HV, 59 HRC) for the second stage [ 2 ]. Wear-resistant cast irons with added vanadium and a low chromium content (e.g., C = 2.2–2.7, V = 6, Cr = 1; in wt%) achieve hardness in the range of 600–900 HV after heat treatment [ 4 ].…”

“…The highest P content is found in grey cast irons: in common grades, it is less than 0.6 wt% [ 20 , 29 ], while in those with good castability and wear resistance requirements, the P content is 0.6–1.8 wt% [ 20 ]. In other cast irons and steels, phosphorus is present in much lower amounts [ 1 , 30 , 31 , 32 , 33 ]. Although it is present in very small amounts, its characteristic segregations can cause problems [ 20 , 33 , 34 ] and make steel sheets brittle [ 34 ].…”