Strain Aging Properties Of High-Strength Hot-Rolled Steels 770165
The need of the automotive industry for low cost, high-strength steel has prompted consideration of the strain aging process as a means of achieving this goal. To determine the steel best suited for these strained and aged applications, both the static and dynamic strain aging characteristics for carbon steel and various hot-rolled, high-strength steels representing yield strengths from 40 ksi (276 MPa) to 107 ksi (738 MPa) were determined. The medium-strength (40/50 ksi - 276/345 MPa) renitrogenized steels with high soluble nitrogen levels were found to offer an excellent combination of good ductility, large strain aging response and high strength levels in the finished automotive part at low cost. For difficult forming operations, the dynamic strain aging process utilizing the titanium-strengthened 80 ksi (552 MPa) steel offers a useful technique, providing improved ductility at elevated forming temperatures while retaining high strength levels in the finished part.