B/P Co-added Dual Phase Steel

Controllable Surface Oxides

A dual phase steel whose selective surface oxidation can be tuned between coarse external oxides and fine dispersed particles by adjusting dew point, providing a basis for optimized galvanizing.

Xutong, Wang · Xuanyu, Zhang · Tianyu, Luan · Li, Yan · Bai, Qin · Xu, Jifang · Teng, Huaxiang · Guangxin, Wu

Corrosion Science 2026

Specifications

Surface B peak at −50 °C

{'zh': '12.42', 'en': '12.42'} wt%

Surface B peak at −30 °C

{'zh': '3.61', 'en': '3.61'} wt%

Surface B peak at −10 °C

{'zh': '3.41', 'en': '3.41'} wt%

Reduction in surface B peak (−30 °C vs −50 °C)

{'zh': '71.0', 'en': '71.0'} %

Reduction in surface B peak (−10 °C vs −50 °C)

{'zh': '72.5', 'en': '72.5'} %

Surface Si/Mn peak ratio at −50 °C

{'zh': '0.15', 'en': '0.15'}

Surface Si/Mn peak ratio at −10 °C

{'zh': '0.11', 'en': '0.11'}

Advantages

Tunable oxide morphology

Adjusting the dew point converts coarse external oxides into fine dispersed particles, improving zinc wettability.

Large reduction in B enrichment

Raising the dew point from −50 °C to −30 °C or −10 °C reduces the surface B peak by over 70%, mitigating the negative effect of B on galvanizing.

Enhanced P enrichment

At high dew point (−10 °C), surface P enrichment is enhanced, which may favor subsequent reactions with the zinc coating.

Applications

• Automotive AHSS：For automotive lightweighting, tuning dew point reduces brittle oxides and improves zinc adhesion.
• Hot-dip Galvanized Steel：Pre-annealing dew point control avoids detrimental surface oxides, enhancing hot-dip galvanizing wettability and coating quality.
• Steel Surface Treatment：As a surface conditioning method, selective oxidation can be managed via dew point, replacing complex post-treatments.