| 摘要 |
The invention provides a high strength cold rolled steel sheet having excellent chemical conversion treatment property stably even Mo is added aiming high strengthening. The surface property of the cold rolled steel sheet satisfies that the characteristic of 10μm or more of the maximum depth (Ry) of the unevenness and 30μm or less of the average spacing (Sm) of the unevenness, and that either one or more preferably both of, the characteristic of the load length ratio (tp40) of the unevenness of the surface is 20% or less, and the characteristic of the difference of the load length ratios (tp60) and (tp40) is 60% or more, is satisfied, and the crack of 3μm or less width and 5μm or more depth does not exist on the surface. |
