by George Langford, Sc.D., Massachusetts Institute of Technology, Cambridge, MA, 1966
2005 by George Langford
Low Alloy Steels - Lesson 3 - Fifth specimen
Pearlite in a spheroidized tool steel at 100X etched
Tool steel bars like this one (1% carbon, 0.2% silicon, 0.2% manganese and 0.2% vanadium) are always delivered in the spheroidized (i.e., annealed) condition.  However, there is pearlite present here (100X, Nital etch at left) which does not machine as well as spherodite (ferrite plus large, spheroidal cementite particles).

In the middle photomicrograph below at 500X you can resolve the microstructure better.  There is a mixture of proeutectoid ferrite and pearlite which formed from austenite of near eutectoid composition. 
Evidently, the carbon content is subnormal in this part of the specimen, and the cooling rate during annealing was too rapid to permit the pearlite to spheroidize while it was forming.
Pearlite in a spheroidized tool steel at 500X etched
Ordinarily, at this (intended) carbon content there would be spheroidized proeutectoid cementite, because the annealing treatment is started from just above the eutectoid temperature rather than from the all austenite phase field.  The lower starting temperature avoids any precipitation of excess cementite on the austenite grain boundaries
Normal microstructure in a spheroidized tool steel at 500X etched
The last photomicrograph from this specimen shows a different place on the specimen where the microstructure is more nearly normal: proeutectod cementite plus partially spheroidized pearlite at 500X.

The last specimen in this lesson is a tool steel which was abusively cut with an abrasive disk.