| 摘要 |
This invention is directed to an improved zinc containing metallic coated ferrous product, particularly sheet and strip, which is resistant to intergranular penetration by zinc and embrittlement of the ferrous base. Use of such zinc containing metallic coated ferrous product in elevated-temperature service, such as found with certain appliances and automotive exhaust components, is enhanced by the coated products of this invention. The resistance to embrittlement of the zinc containing metallic coated ferrous base, when subjected to elevated service temperatures, is achieved by the use of a high-phosphorus containing steel base. For a plain content steel base, a phosphorus content of at least 0.020% by weight, preferably at least 0.030%, and more preferably at least 0.039% was found sufficient to render such zinc-alloy coated ferrous base resistant to embrittlement by zinc. By use of such high phosphorus ferrous base, for the reception of a zinc containing alloy coating, an improved metallic coated ferrous product has been found which resists intergranular penetration by zinc and embrittlement of the ferrous base. Such coated product has extended service life at temperatures above about 450 DEG F. (232 DEG C.) and when restored to room temperature possesses a high degree of ductility. |
