The blacksmith's guide : valuable instructions on forging, welding, hardening, tempering, casehardening, annealing, coloring, brazing, and general blacksmithing (1907)
Sallows, J. F. (James Francis), 1865- · Brattleboro, Vt. : The Technical Press · leaf 84
HARDENING AND TEMPERING 71 … C. Structure at edge of overheated bar. D. Showing change in structure near edge of bar. Fig. 2. Micro-photographs showing Variation in Structure of Overheated Bar.
Blacksmithing
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
