Zinc coatings for hot sheet metal forming: Comparison of phase evolution and microstructure during heat treatment

Kondratiuk, Jens; Kühn, Patrick; Labrenz, Eckhard; Bischoff, Christine

doi:10.1016/j.surfcoat.2011.03.002

Cited by 71 publications

(58 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The angle of scanning was (2): 4°-70°. intermetallic, however this phase was not observed in the present study [5]. …”

Section: Methodscontrasting

confidence: 77%

“…The blank transfer from the furnace to the press might promote some steel oxidation. In order to avoid this phenomenon, coatings are applied on the blank [5]; [6].…”

Section: Introductionmentioning

confidence: 99%

“…Thus, alternative coatings zinc base, have been developed. Zn-Ni is one of alternative to Al-Si; it is an electrodeposited coating, which consists in around 15 % in mass of nickel [5]; [6].…”

Section: Introductionmentioning

confidence: 99%

“…It is known that the heating causes chemical elements diffusion that results in intermetallics formation amongst the elements presents in the coating and base metal [5].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The use of X-ray diffraction for phase identification of press hardened steels

Couto¹,

Costa²,

Martinez³

et al. 2016

Blucher Physics Proceedings

View full text Add to dashboard Cite

The numbers of hot stamped components have been steadily increasing in the automotive industry. Press hardened steels are generally used in hot stamping process since at the end of the process, the steel may achieve a tensile strength about 1500 MPa. The hot stamping process consists to heat the steel blank at total austenitization temperature and to transfer the blank into the press tooling for shaping and fast cooling to fully martensitic transformation. The transfer of the blank from the furnace to the press might promote at some extent, steel oxidation. The application of metallic coatings avoids this hindrance. The AlSi has been the most applied coating on steel. In parallel, alternative coatings such as Zn-Ni have been ResumoÉ crescente o número de componentes estampados a quente destinados a indústria automotiva. Os aços endurecidos por estampagem (PHS) são geralmente usados no processo de estampagem a quente porque ao final do processo o aço atinge resistência mecânica próxima a1500 MPa. O processo de estampagem a quente consiste em aquecer um blanque em temperaturas de total austenitização e transferi-lo do forno de aquecimento para uma prensa. Nesta prensa, ocorre a conformação mecânica e o resfriamento brusco para total transformação martensítica. O estágio de transferência do forno para a prensa pode promover alguma oxidação do aço. A aplicação de revestimentos ao blanque evita esse fenômeno. O revestimento Al-Si tem sido o mais aplicado. Paralelamente, estudos de revestimentos alternativos como o Zn-Ni estão sendo realizados. Sabe-se que o aquecimento favorece a difusão dos elementos químicos que resulta na formação de intermetálicos entre os elementos presentes no revestimento e no substrato. Este estudo teve o objetivo de caracterizar as fases presentes em amostras estampadas e revestidas por Zn-Ni e Al-Si pela da técnica de difração de raios X. Não foram identificadas fases sugeridas pela literatura como Zn-Fe, Zn-Ni-Fe ou A-lSi-Fe. Mesmo assim a difração de raios X detectou a presença de ZnO e α-Fe para a chapa de aço revestida com Zn-Ni e para a chapa de aço revestida com Al-Si, a presença de Al5Fe2, AlFe3 e α-Fe.Palavras chaves: PHS, fases, difração de raios X.

show abstract

“…The angle of scanning was (2): 4°-70°. intermetallic, however this phase was not observed in the present study [5]. …”

Section: Methodscontrasting

confidence: 77%

“…The blank transfer from the furnace to the press might promote some steel oxidation. In order to avoid this phenomenon, coatings are applied on the blank [5]; [6].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…It is known that the heating causes chemical elements diffusion that results in intermetallics formation amongst the elements presents in the coating and base metal [5].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The use of X-ray diffraction for phase identification of press hardened steels

Couto¹,

Costa²,

Martinez³

et al. 2016

Blucher Physics Proceedings

View full text Add to dashboard Cite

show abstract

“…Zn and Zn-alloyed coating are therefore being developed. 14,15) However, the formation of small surface cracks on die-quenched Zn-coated PHS panels related to liquid metal induced embrittlement (LMIE), has been widely reported. 8) Because of the low melting temperature of Zn and Fe-Zn intermetal-© 2015 ISIJ lic compounds, most of the Zn and Zn-alloy coatings are partially liquid at the austenitizing temperature.…”

Section: Introductionmentioning

confidence: 99%

Liquid-Metal-Induced Embrittlement Related Microcrack Propagation on Zn-coated Press Hardening Steel

et al. 2015

View full text Add to dashboard Cite

The coatings on press hardening steel are needed to suppress high temperature oxidation and decarburization. Additional corrosion protection is provided by Zn coatings which provide cathodic protection to press hardened parts. Due to the low melting temperature of Zn and Zn-Fe intermetallic compounds, the Zn-coated PHSs are susceptible to LMIE during the die-quenching process. In the present work, the mechanical properties of Zn coated PHS were evaluated in terms of tensile properties and bending properties. A deterioration of the room temperature bendability, due to microcrack formation and propagation, was observed. The presence of Γ-Fe3Zn10 observed in the microcracks at room temperature correspond to liquid Zn at the die-quenching temperature, making it possible to trace the progress of the liquid Zn phase during microcrack formation. The results suggest that Zn-grain boundary diffusion causes the phase transformation to ferrite of the austenite grain boundary region. This results in intergranular cracking due to the lower strength of ferrite. The LMIE microcrack formation is most severe in areas where the applied stress and the friction are highest during the forming process, making the occurrence of LMIE-mitigated microcrack propagation dependent on the local deformation conditions.

show abstract

Complementary in‐situ electrochemical ICP‐OES and corrosion studies of hot‐formed zinc alloy coated steel

Wiesener

Schinkinger

Grundmeier

2015

Materials & Corrosion

View full text Add to dashboard Cite

A spectroelectrochemical approach for the fundamental analysis of the cathodic corrosion behavior of hot‐formed zinc alloy coated steel based on the in‐situ combination of inductively coupled plasma‐optical emission spectroscopy (ICP‐OES) is presented. Complementary to the microscopic information on the alloy dissolution, line‐scans of the free corrosion potential were measured across welding spots with a scanning capillary cell (SCC) to illustrate both the change in the local coating integrity and the ability of the coating to cathodically protect possible defects in the welding spot area. These studies were performed as a function of the holding time during hot‐forming. The results of the coulometric ICP‐OES measurements and the potential line‐scans are in very good agreement and show that in‐situ ICP‐OES provides insight into the dissolution behavior of zinc alloys that goes far beyond standard electrochemical techniques such as coulometry alone. It could be shown that the hot‐forming induced alloying of zinc with iron leads to preferential dissolution of zinc in the initial phase and to a parallel dissolution of iron and zinc in the second phase. For zinc‐nickel alloys the initial preferential zinc dissolution leads to a fast de‐alloying and the dissolution of the nickel rich phase occurs at rather anodic potentials. The alloying of nickel into zinc coatings leads to an inhibition of the zinc dissolution and hence to a decrease of the cathodic corrosion protection ability. However, the zinc‐nickel coatings are more resistant to evaporation and the defect formation in the welding spot is less significant. It could be shown that under the same conditions an aluminum silicon alloy does not show a significant preferential anodic dissolution hinting at a negligible cathodic protection.

show abstract

Zinc coatings for hot sheet metal forming: Comparison of phase evolution and microstructure during heat treatment

Cited by 71 publications

References 20 publications

The use of X-ray diffraction for phase identification of press hardened steels

The use of X-ray diffraction for phase identification of press hardened steels

Liquid-Metal-Induced Embrittlement Related Microcrack Propagation on Zn-coated Press Hardening Steel

Complementary in‐situ electrochemical ICP‐OES and corrosion studies of hot‐formed zinc alloy coated steel

Contact Info

Product

Resources

About