A material dedicated to open gearing applications
FerryNod® is a ferrous alloy grade that covers a hardness range from 250 BHN (FerryNod®250) to 340 BHN (FerryNod®340). It allows guaranteed minimum mechanical properties and hardness in thick cross-sections (>100 mm). FerryNod® material grades do not have direct equivalents in published standards. FerryNod® Grades 320 to 340 are the subject of technical patents.
Physical Properties Guaranteed
- Range : from 250 to 340 BHN (minimum guaranteed on casting)
- FerryNod®is a very homogenous material: on a 200 mm thickness cross-section, the maximum hardness loss is 5
Mininum mechanical properties guaranteed beyond material standard limits
Material standard eN 1563 does not specify minimum mechanical properties for high hardness material, having thick cross-sections (see table below).
FerryNod® bridges the gaps in the specification by guaranteeing mechanical properties on thick cross- sections.
Minimum mechanical properties values guaranteed by Ferry Capitain for FerryNod® grades
Gear design standard ISO6336, Section 5, specifies the maximum allowable contact (tooth flank σhlim) and bending (tooth root σFlim) stresses as a function of material hardness (see graphs below). FerryNod® grades meet or exceed the specified stress values of this standard.
ISO6336 does not specify allowable stress values for hardness above 300 BHN. FerryNod® 310 to 340 material grades allow the limitations of the standard to be exceeded, and to achieve higher allowable contact and bending stresses.
the presence of graphite nodules provides inherent lubricity and enhances a better vibration damping properties
Welding trials and mechanical testing conducted specifically on SGI gear teeth have shown that a serviceable repair on an installed gear is possible, with only minor losses in fatigue strength. As such, any production stoppages due to damaged gearing should be minimized. Ferry Capitain has established a formal repair procedure (PR2/89).