Sorbite

According to Boynton this constituent is sorbite in the case of steels containing more than ·8 per cent. carbon, for if troostite be β iron free from carbon it cannot exist in hyper-eutectoid steels.

After a very long period of annealing their morphology is very similar to the carbides precipitated in the sorbite and, as regards the amount of precipitate, the ferritic grains are almost indiscernible from the sorbitic (Fig.3).

Some consider granular pearlite or granular cementite to be sorbite. Hence it is also called sorbitic pearlite, and when referring to the contained carbon, sorbitic carbide.

Sorbite is isomeric with mannite and dulcite, and forms with oxalic acid at 75° sorbite-formamide, with evolution of carbonic anhydride. It is a colourless odourless syrup.