Introduction to Cast Iron Heat Treatment

Abstract

This article introduces the general principles and applications of heat treatment to iron castings. It provides a detailed discussion on the heat treatment processes, namely, stress relieving, annealing, normalizing, throughhardening, and surface hardening for various types of cast irons. These include gray iron, ductile iron, compacted graphite iron, white iron, malleable iron, and high-alloy iron. The article describes how to control temperature and atmosphere during the heat treatment of the iron castings.

Effect of manufacturing processes on the natural frequency, surface roughness and dimensional tolerances of GCI brake discs

“…The presence of residual stresses has a significant impact on cast iron components. This can invariably lead to significant degradation of the most crucial material properties, such as reduced fracture toughness, accelerated stress corrosion, decreased fatigue resistance, and undesirable shape distortions, which may compromise the fulfilment of geometrical tolerance requirements [19][20][21][22][23][24][25]. Residual stresses frequently result in expensive hidden issues, the repercussions of which are felt throughout the service life of a component.…”

“…Gray cast iron brake rotors may still contain a sizable amount of residual stress after casting operations. Generally, manufacturers can reduce residual stresses in metallic components by controlling the magnitude and type of residual stresses through stress-relief heat treatment, regulating heat-treatment processes, mechanical treatment, and alloy selection [25]. Thermal processing can reduce residual stresses, which are thermally unstable.…”

Improving mechanical properties of carbon and tool steels via chromizing

“…Steels possess high hardness, toughness, wear resistance and durability [1]. Due to their favourable mechanical properties, steel materials are widely used in a variety of engineering applications with sliding interfaces such as cutting tool materials in metal cutting, wood machining [1][2][3], biomass comminution systems [4][5][6], machinery components in bearings [7], gears [8] and shafts [9] or as rails and wheel materials in the railways sector [10].…”

“…Among different coating and diffusion-based surface treatment techniques, chromizing has been applied to ferrous alloys to increase their corrosion and high-temperature oxidation resistance [11][12][13][14] and to improve the wear [12][13][14][15], hardness [16][17][18], and adhesion properties [15,17]. The main advantage of chromizing over other surface hardening methods such as boron or titanium treatments is corrosion resistance [9]. Due to these favourable properties, chromized steel materials are used in applications such as heat exchanger tubing [19,20], timing chains in vehicles [19], automotive exhausts [21] or sealing cans for the food industry [19].…”