Coarse carbides by multiple annealing - 1.7034
The reason for the formation of coarse carbides, at constructional and tool steels, is almost always an annealing with wrong heat treatment parameters. Temperature and annealing time play the largest role. The initial structure before annealing can affect the result also. For example, pearlitic structures with coarse lamella rather inclines to form coarse carbides than bainitic microstructures or fine lamellar pearlite structure conditions. In the following example the material is repeatedly annealed. The carbides have grown strongly through this, while the number of individual carbides has been reduced.
Rod wire 25,00 mm round - spheroidised