Hardening of the surface is necessary for work pieces exposed to severe work conditions such as hydraulic cylinder rods on earth moving equipment. This process makes the surface much more resistant to scraping, gouging, and denting caused by hard objects striking the outside diameter.
This process is mainly used on hydraulic cylinders; other applications include ball screws to increase the wear resistance in the ball track and other round parts
The technology is based on the induction hardening process. Induction hardening uses eddy currents to produce heat on the surface of the work piece. Eddy currents are evoked by one or more induction coils with high frequency alternating current.
The number of induction coils used, is determined by the required through feed speed, depth of hardness and the diameter of the bars or pipes.
A continuously running transport system feeds the steel bars through the induction coils at a consistent speed.
Specifically engineered transport system, controlled by the PLC, is designed for maximum efficiency and production. The extremely accurate and repeatable spiral movement insures consistent hardness and hardening depth throughout the complete bar.
The outer surface heats up to the required hardening temperature. Deeper layers will not reach this temperature during the short heating period and therefore will not be hardened.
Immediately after heating, the bar or tube is quenched with an emulsion or with water. The quenching medium is applied by an automatically operating quencher.