Warm oil having greater fluidity enables more rapid convection currents to be set up and to carry off the heat. As explained in the article on the iron-carbon phase diagram, the carbon atoms in the austenite lattice each occupy the space inside the face-centered cubic unit cells. Steam also causes stirring action at the surface of the bath. Emulsions invariably form layers with water at the bottom of the tank. Cooling coils, or even heating coils, depending on the need, are used in the tank. Water Quenching Steel. This aspect of organic quenchant is of great importance, as much cheaper components can be produced. Hot, or cold water flows through the heat exchangers fitted in the bath. Due to the Leidenfrost phenomenon, immersion quenching is a more or less uncontrolled task, because prediction of the appropriate rewetting process is difficult. Temperature of oil should not be so high that it flashes, or burns, when object is immersed in it. If, on the other hand, the focus is on achieving high strength with high toughness, the tempering temperatures are selected accordingly higher. It is suggested that aqueous chloride solutions with special additives preventing metal surface corrosion and reducing separation of components containing chlorine are used as quenching media realizing rapid quenching methods for alloy steels. As it is the amount of heat required to change unit mass of liquid coolant to vapour at a constant temperature, a coolant with low latent heat of vapourisation changes into vapour easily, and thus shall promote the ‘A’ stage of cooling, i.e. It consists of aluminium oxide particles in a retort, fluidized by a continuous stream of gas blown upwards through the base of the retort. The paper discusses results of computer simulation connected with the double distortion during batch quenching of of spur gears caused by a local film boiling between teeth. Quenching stage of hardening heat treatment is a difficult and complex step. Before proceeding to consider the cooling characteristics of commonly used coolants, it may be advantageous to study what happens when a heated steel object (say at 840°C) is plunged into a stationary bath of cold water. There are two main requirements of contradictory nature: 1. Presence of soap in water prolongs ‘A’ stage, similar to increase of temperature of the water. In an oil-quench, a considerable variation is possible by the use of animal, vegetable, or mineral oil, or blends of two, or more of these varieties. In industry, water as a coolant is used to harden plain carbon steels and some low alloy steels, i.e., the shallow-hardening steels. These conditions induce large internal stresses. Such oils are mineral oils (usually of petroleum type).