Cold rolled steel sheet and hot dip zinc-coated cold rolled steel sheet having excellent bake hardenability, non-aging properties and formability, and process for producing same
US5470403A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 18, 1994 |
| Grant date | Nov 28, 1995 |
| Priority date | — |
| Expiry date | Feb 18, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12799
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The present invention provides a cold rolled steel sheet and a hot dip zinc-coated cold rolled steel sheet excellent in paint bake hardenability, non-aging properties and formability, and a process for producing the same. In the present invention, an extremely low carbon steel or extremely low carbon steel containing at least one element selected from the group consisting of Ti and Nb is used as a base steel, and Mn and Cr are positively added thereto, whereby the resultant steel has a mixed structure after annealing. Accordingly, there can be obtained a steel sheet having both a high paint bake hardenability and non-aging properties, and being excellent in formability such as an average r-value (deep drawability). With regard to the paint bake hardenability, the present invention may provide a cold rolled steel sheet and a hot dip zinc-coated cold rolled steel sheet to which paint bake hardening may be optionally imparted in an amount as large as about 10 kgf/mm.sup.2 and which also have non-aging properties.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.