Lift-Off of Surface Oxides During Galvanizing of a Dual-Phase Steel in a Galvannealing Bath

Effects of alloying elements on surface oxides of hot–dip galvanized press hardened steel

“…Bellhouse and McDermid [27] found that different thermal expansion coefficients of oxides and Fe are responsible for chipped off oxides during annealing and quenching on TRIP steel. Chen et al [11] confirmed this behavior in a dual phase steel similar to the investigated steel grades. Due to the storage of the specimen in standard atmosphere, the Zn patina has already started to alter and form Zn(OH)2 [28] as HIM-ToF-SIMS measurements confirm.…”

“…They found that higher C contents, as well as higher contents of the alloying elements Mn and Cr result in more stable -Fe(Zn) but the evolution of the surface oxide region was not investigated in their work. Chen et al [11] focused on the effects of surface oxides on the steel strip before galvanization and compared standard Zn coatings on dual phase steels with ZnFe galvannealed coatings. Wang et al [12] described the diffusion process for the ZnFe phase depending on the Zn concentration in GA coated 22MnB5.…”

Effect of Dew Point on the Selective Oxidation and Reactive Wetting of DP980 Steel during Hot‐Dip Galvanizing

“…[2] Therefore, the Al-rich inhibition layer formed in this work is very thin and discontinuous, and more iron and zinc diffuse to form Fe-Zn compounds, which can be observed at many interfaces after GI in a zinc bath with low Al content. [36,45] Khondker et al [42] determined that the reduction of MnO is thermodynamically possible by the reaction shown in Equation ( 4), although no direct evidence is observed in the present work. 3MnOðsÞ þ 2AlðsÞ!…”

“…The bow‐shaped oxide layer at the steel‐coating interface and the zinc‐rich layer beneath it in the study of Minenkov et al support this theory as well. [ 38 ] Chen et al [ 45 ] discovered the phenomenon of stripping and incorporation into Fe–Zn intermetallic compounds of MnO after GI in liquid zinc containing 0.125% Al through TEM.…”

“…The bow-shaped oxide layer at the steel-coating interface and the zincrich layer beneath it in the study of Minenkov et al support this theory as well. [38] Chen et al [45] discovered the phenomenon of stripping and incorporation into Fe-Zn intermetallic compounds of MnO after GI in liquid zinc containing 0.125% Al through TEM. Furthermore, surface oxide cracking and spalling may also result from oxide mismatch stress brought on by the differential in the coefficient of thermal expansion (CTE) between the steel substrate and the oxide during cooling.…”