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Gears From Deformed Bainitic Ductile Iron

#G-1166


Influence of Hot Plastic Deformation and Austempering on Structure-Property Relationships in New Ductile Iron for Gears

Tech Area / Field

  • MAN-MAT/Engineering Materials/Manufacturing Technology
  • MAT-ALL/High Performance Metals and Alloys/Materials

Status
3 Approved without Funding

Registration date
20.07.2004

Leading Institute
Georgian Technical University, Georgia, Tbilisi

Collaborators

  • University of Illinois At Urbana-Champaign / Department of Mechanical and Industrial Engineering, USA, IL, Urbana\nNew Mexico Institute of Mining and Technology / Mechanical Engineering Department, USA, NM, Socorro\nTohoku University / Institute for Materials Research (IMR), Japan, Sendai

Project summary

As is well known, gears belong to the most widespread and important machine parts. Improvement in working characteristics of gears materials has a beneficial effect on the performance and competitiveness of machines and mechanisms. For example, due to its higher wear and contact fatigue resistance, higher plastic limit, and lower heat treating cost, ADI is a commercially available alternative to steel for gear applications. As manufacturers have confirmed, employment of ADI gears cuts the gear noise by 50% and reduces the production costs of various devices. In our opinion, the most promising ADI are deformable ADI – a new class of ADI that we have developed. They can be used for manufacture of various machine parts by casting, pressing, rolling and extrusion. That will allow reducing the metal loss and improving the operation characteristics of products. Hot plastic deformation of cast iron favours changes in the graphite inclusion shapes, amount and distribution of structure defects, and state and activity of interphase and intergrain boundaries; promotes an increase in the metallic matrix dispersion, and affects the processes of polygonization and recrystallisation of the structure. The character of structure changes depends on the plastic deformation degree of cast iron.

The mentioned changes affect ambiguously formation of the cast iron structure and properties at subsequent austempering, which, as known, is essential for production of the cast iron of high quality. For effective application of deformable ADI, it is essential to study the effects of the degree of dispersion on temperature-kinetic parameters of formation of the cast iron structure and properties during austempering of the ductile caste iron. The obtained results have allowed us to determine the optimal conditions of deformation and subsequent austempering of the cast iron, which provide manufacture of gears with high operation characteristics.

The aim of present work is an investigation of the effects of hot plastic deformation and austempering on structure-property relationships in ductile iron for substantiating scientifically new technologies for production of gears.


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