Effect of Coating Structure on Powdering Resistance of Galvannealed Steel Sheet

Sakurai, Michitaka; Zhang, Li Wei; Tajiri, Yasuhisa; Kondo, Takaaki

doi:10.4271/920174

Cited by 2 publications

(4 citation statements)

References 4 publications

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“…Xray diffraction was performed using a diffractometer with CuK a source, on the top surfaces of 28 mm diameter coupons. Phases were identified using the methods described in refrences 11,21) For cross-sectional examinations samples were polished using diamond paste and etched by immersing in 3% nital solution in alcohol.…”

Section: Draw Bead Testsmentioning

confidence: 99%

“…These include relatively simple tests such as Ubend, 4,5) 60°V bend type tests 6,7) and Luniaxial tensile tests. 8) More sophisticated tests, such as Double-Olsen, 9) cylindrical-cup 10) and draw bead tests [11][12][13][14] provide more realistic simulations of the actual stamping processes in laboratory environment.…”

Section: Introductionmentioning

confidence: 99%

“…Urai et al 16) also showed that the powdering resistance increased when the Al content of the galvanizing bath was increased. On the other hand, Sakurai et al 11) sought a correlation between the ratio of the gamma 1 (G 1 ) phase and the total gamma amount (i.e., the sum of G and G 1 ) and concluded that the increase in the percentage of G 1 phase in the coating improved the powdering resistance. Sakurai et al 11) also noted that an increase in the thickness of G phase layer would deteriorate the powdering resistance.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, Sakurai et al 11) sought a correlation between the ratio of the gamma 1 (G 1 ) phase and the total gamma amount (i.e., the sum of G and G 1 ) and concluded that the increase in the percentage of G 1 phase in the coating improved the powdering resistance. Sakurai et al 11) also noted that an increase in the thickness of G phase layer would deteriorate the powdering resistance. Jordan et al 6) proposed that the powdering resistance should decrease when the thickness of "the interfacial layer" (presumably G ) exceeded 1 mm.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Microstructure on Fracture Mechanisms in Galvannealed Coatings.

Alpas

Inagaki

2000

ISIJ International

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Fracture mechanisms in galvannealed coatings have been studied by performing draw bead tests on galvannealed Ti stabilized interstitial free and Aluminum killed low carbon steel sheets and by investigating coating microstructures by scanning electron microscopy. Galvannealing treatments, on samples galvanized using an industrial hot-dip galvanizing process, were conducted at 450, 500 and 550°C for several time periods between 1 and 360 s in a laboratory induction furnace.In the coatings with low Fe content (up to 5 g/m 2 ), the amount of powdering during the draw bead test was minimal. Growth of cracks nucleated within the d 1 phase was arrested at the steel-coating interfaces where only a limited amount of decohesion occurred. A steep increase in the amount of powdering was observed in coatings with Fe contents between 6-9 g/m 2 . In these coatings, cracks originating from the d 1 phase reached G-G 1 -d 1 phase boundaries, which provided preferential crack growth paths and thus facilitated fracture within the coating. A fracture mechanics model was proposed to account for the powdering resistance of galvannealed coatings.

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Section: Draw Bead Testsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Microstructure on Fracture Mechanisms in Galvannealed Coatings.

Alpas

Inagaki

2000

ISIJ International

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Influence of Si Oxide on Fe-Zn Galvannealing Reaction of Si-added Steel Sheet

Makimizu¹,

Suzuki²,

Yamada³

et al. 2015

Journal of The Surface Finishing Society of Japan

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The influences of external and internal Si oxides on the galvannealing reaction of 0-1.8%Si-added steel were investigated. Internal and external Si oxides formed by recrystallization annealing at the dew points of 223-263 K. The distribution of Si oxides in the subsurface region of the substrate steel was analyzed using glow discharge optical emission spectroscopy, reflection electron microscopy, and transmission electron microscopy. External Si oxides suppressed the galvannealing reaction. Then the ζ phase formed locally at the interface between the substrate steel and the zinc coating after galvanizing, which suggests that the external Si oxides at the steel surface acted as a barrier to the Fe-Zn reaction. When Si oxidized internally, a depleted zone of solute Si was observed in the subsurface region of the substrate steel. In this case, the galvannealing reaction was accelerated in comparison with that when Si did not oxidize. Furthermore, decrease of the solute Si content led to acceleration of the galvannealing reaction, nucleation of the ζ phase, and growth of the Γ phase. From these results, it was concluded that depletion of solute Si attributable to internal oxidation of Si accelerated the galvannealing reaction.

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Effect of Coating Structure on Powdering Resistance of Galvannealed Steel Sheet

Cited by 2 publications

References 4 publications

Effect of Microstructure on Fracture Mechanisms in Galvannealed Coatings.

Effect of Microstructure on Fracture Mechanisms in Galvannealed Coatings.

Influence of Si Oxide on Fe-Zn Galvannealing Reaction of Si-added Steel Sheet

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