Remarkable Features of Salt Bath Heat Treatment

13 April 2021

Different heat treatment processes are being conducted when working with steels and other types of metals due to numerous reasons. One of the key reasons why these materials undergo the said processes is to improve their overall strength and hardness. These processes can also provide them resistance to elements, particularly corrosion. The physical properties of the materials as well as their ductility are likewise altered by heat treatment processes.

Overview of Salt Bath Heat Treatment

One particular process that can provide numerous additional features to different types of steels is known as the salt bath heat treatment. This specific process is often conducted in a furnace that has a ceramic or metal container and is filled with molten salt. The salt bath heat treatment utilises one or more types of salts, nitrates, chlorides, carbonates, cyanides, caustics, and small amounts of other additives.

An involved workpiece is often immersed for the heating process, with the heat being transferred between the said material and molten salt through conduction. The cooling process can also be done with salt bath heat treatment thanks to the excellent conductivity of molten salt. 

Heat is generated by the furnace through its resistance to current passage, with heavy electrode bars causing salt circulation once the electromagnetic forces are energised. A strong magnetic field is then created between electrodes, causing salt particles to move downward. The movement of these particles can ensure that the bath will obtain absolute temperature uniformity throughout the heat treatment.

Salt Bath Heat Treatment Features

One great feature of salt bath heat treatment is that it can work on and cater to different types of steels. This treatment can process low, medium, and high-carbon steels. Even ceramics and plastics can be processed with salt bath heat treatment.

Another great feature of salt bath heat treatment is that it can effectively provide quick heating of a workpiece. As the workpiece is immersed into the furnace, it is effectively heated through conduction by maximising the liquid media. With liquid media, the heat transfer rate is deemed faster than other heating mechanisms like radiation and convection by gas. Immersing the workpiece in a salt bath can likewise protect the workpiece from the effects of the atmosphere.

As mentioned before, salt bath heat treatment can also be great in terms of cooling. The cooling process in the molten salt is known to be slower compared to conducting it in other quenching media. The former can even stop at a much lower temperature. Conventional quenching processes, alternatively, often have a high cooling rate, which could only cause cracks and distortions on the workpiece.

Salt Bath Heating at Alpha Detroit

Salt bath heat treatment can effectively conduct numerous processes such as quenching, hardening, nitriding, carbonitriding, carburising, solution treatment, and deep brazing. If you want to know more about high-temperature salt baths, feel free to contact us at Alpha Detroit. We provide a wide range of services for all your heat treatment needs. Our expertise allows us to suggest the most appropriate process for your heat treatment requirements.

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