Hot-rolled ferritic steel for motor vehicle exhaust members.

摘要

A hot-rolled ferritic steel capable of being used in a hot-rolled annealed condition as a material for a motor vehicle exhaust system including: about 0.02 wt% or less of C, about 0.8 wt% or less of Mn, about 0.015 wt% or less of N, about 0.02 wt% or less of Al, about 0.02 wt% or less of Ti, about 0.02 wt% or less of Zr; said steel further comprising the critical inclusion of: about 0.4 to 2 wt% of Si, about 6 to 17 wt% of Cr, about 0.025 to 0.10 wt% of P, about 0.35 to 0.60 wt% of Nb; and the balance Fe and incidental impurities. The weight percentages of the above components satisfy the following equations (1) and (2): <MATH> <MATH> such that a low-cost ferritic steel is produced which, after conventional hot rolling, exhibits characteristics well-suited for motor vehicle exhaust systems such as high workability, high heat resistance and good manufacturability.