Patent ID: 8114224

Claim:
A process for making an articulated structural part comprising: providing a part made from steel having carbon content by weight in the range of about 0.4% to about 0.6%; carburizing said part laminarly up to a carburized depth of 0.5 mm below a surface of said part and achieving a carburized part having increased carbon content by weight of up to 1.3% such that a surface layer of the carburized part contains martensite and residual austenite; cooling said part after carburizing to a temperature of about 250° C.; and after cooling said part, then hardening said carburized part to a hardened depth being greater than the carburized depth by induction hardening, wherein induction hardening is carried out at a frequency in the range of about 8 kHz to about 15 kHz, a power range of about 150 kW to about 300 kW, and a heating period in the range of about 1 to about 15 seconds.