Effect of dew point on the surface selective oxidation and subsurface microstructure of TRIP-aided steel

Liu, Huachu; He, Yanlin; Swaminathan, Srinivasan; Rohwerder, Michael; Lin, Li

doi:10.1016/j.surfcoat.2011.08.038

Cited by 49 publications

(26 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…2, which presents GDOES analysis for the same sample. Through comparisons between carbon concentration profiles before (blue line) and after (red line) the selective oxidation test, it can be observed a strong decarburization after that test (>120µm in depth).Similar to the present study, Liu et al [7] found a ferrite layer (decarburization depth) of about 20 µm depth. Moreover, a small mass gain linked to oxide formation was also observed.…”

Section: Tg Analysissupporting

confidence: 89%

Study of Grain Boundary Oxidation of High Alloyed Carbon Steels at Coiling Temperature

Ronqueti¹,

Favergeon²,

Risbet³

et al. 2017

Anais Do Seminário De Laminação E Conformação

View full text Add to dashboard Cite

The effect of coiling temperature on selective oxidation behaviour of binary and ternary iron-based model alloys containing different contents of Si or Mn were investigated by SEM and SIMS. The experiments were carried out with a temperature ranging from 450 °C to 700 °C, under N2-5%H2 gas flow with a Dew Point of -3.3°C, for different durations. SEM images of binary iron-based model alloys revealed a decrease of grain boundary oxidation depth with increasing Silicon or Manganese content. At 530°C and 600°C SIMS results showed no Silicon diffusion toward surface, contrary to the results analyzed for Fe-x%Mn. Tests results and Wagner's theory application (specific cases Fe-0.2%Si and Fe-0.5%Si) showed that grain boundary oxygen diffusion coefficient "Do GB " is almost 60 to 70 times faster than oxygen bulk diffusion coefficient. These results helped to broaden knowledge of single-element effects on grain boundary oxidation, in addition, will contribute of the future works in new steels with complex alloy compositions.

show abstract

Section: Tg Analysissupporting

confidence: 89%

Study of Grain Boundary Oxidation of High Alloyed Carbon Steels at Coiling Temperature

Ronqueti¹,

Favergeon²,

Risbet³

et al. 2017

Anais Do Seminário De Laminação E Conformação

View full text Add to dashboard Cite

show abstract

“…De acordo com as análises via XPS, o manganês foi o elemento que se apresentou mais abundante na superfície propostas por Swaminathan e Spiegel (8) e Liu et al, (12) este pico corresponde ao óxido Mn 3 (PO 4 ) 2 . Guttmann et al (13) observam que o enriquecimento superficial de fósforo em aço endurecido por solução sólida substitucional cresce com o emprego de atmosferas úmidas.…”

Section: Caracterização Do Aço Não Revestido Após Recozimento Contínuounclassified

Efeito Do Ponto De Orvalho Da Atmosfera Dos Fornos De Recozimento Da CGL Na Qualidade Do Revestimento Ga Em Aço Bake Hardenable

Guimarães¹,

Barbosa²,

Gonzalez³

et al. 2013

TMM

View full text Add to dashboard Cite

ResumoA condição superficial do aço após o recozimento contínuo é de extrema importância para a qualidade do revestimento galvannealed (GA). A presença de óxidos ou precipitados pode afetar as reações na interface revestimento/ substrato e diminuir a molhabilidade do zinco na superfície, provocando defeitos no produto final. Visando evitar a oxidação do material durante o recozimento, emprega-se uma atmosfera protetora nos fornos. Mas, apesar dessa atmosfera, é possível a oxidação seletiva ou precipitação de partículas de segunda fase, sendo o ponto de orvalho (PO) um dos fatores preponderantes no sentido de atenuar estas ocorrências. Neste estudo, avalia-se o efeito do PO sobre a qualidade de revestimento GA aplicado em aço bake hardenable. Em um Simulador de Processo de Galvanização a Quente realizou-se um recozimento contínuo sob pontos de orvalho de -60°C, -30°C e 0°C, assim como a galvanização a quente. Conclui-se que o PO é determinante para a quantidade, distribuição e tipo de óxidos formados, sendo a condição de -30°C a que proporciona a obtenção de um revestimento com menos falhas e melhor aderência. Palavras chave: Recozimento contínuo; Ponto de orvalho; Aço bake hardenable; Revestimento galvannealed. EFFECT OF DEW POINT OF ATMOSPHERE OF CGL'S ANNEALING FURNACES ON THE QUALITY OF GA COATING ON BAKE HARDENABLE STEEL AbstractThe strip steel surface condition after continuous annealing of strip is extremely important to the quality of galvannealed coating (GA). The presence of oxides or precipitated can affect the reactions at the coating/substrate interface and decrease the zinc wettability on the steel surface, leading to various defects in the final product. To avoid oxidation of the material during continuous annealing, a protective atmosphere is used in the furnaces. Despite this atmosphere, it is possible the selective oxidation or precipitation of second phase particles, being the dew point of atmosphere one of the leading factors to reduce this occurrence. This study aims to evaluate the effect of the dew point on the quality of GA coatings applied to a bake hardenable steel. The continuous annealing under dew points of -60°C, 30°C and 0°C, as well as hot dip galvanizing, were performed in a Hot Dip Process Simulator. It is found that the dew point has a decisive influence on the amount, distribution and type of oxides formed, and the condition of -30°C provided the coating with less failures and better adhesion.

show abstract

“…[4] One approach to mitigate the formation of external oxides during annealing is by annealing at high dew points to promote internal oxidation of alloying elements. [5] However, alloying element oxides can still be observed at the steel surface after annealing at high dew points, even when the annealing conditions favor internal oxidation. [6] An alternative way to create an oxide-free steel surface during annealing prior to galvanizing is by first forming a uniform thin Fe 1-d O (Wu¨stite) layer at the steel surface that subsequently is reduced into iron.…”

Section: Introductionmentioning

confidence: 99%

Reduction Kinetics of Wüstite Scale on Pure Iron and Steel Sheets in Ar and H2 Gas Mixture

Mao

Sloof

2017

Metall Mater Trans B

View full text Add to dashboard Cite

A dense and closed Wu¨stite scale is formed on pure iron and Mn alloyed steel after oxidation in Ar + 33 vol pct CO 2 + 17 vol pct CO gas mixture. Reducing the Wu¨stite scale in Ar + H 2 gas mixture forms a dense and uniform iron layer on top of the remaining Wu¨stite scale, which separates the unreduced scale from the gas mixture. The reduction of Wu¨stite is controlled by the bulk diffusion of dissolved oxygen in the formed iron layer and follows parabolic growth rate law. The reduction kinetics of Wu¨stite formed on pure iron and on Mn alloyed steel are the same. The parabolic rate constant of Wu¨stite reduction obeys an Arrhenius relation with an activation energy of 104 kJ/mol if the formed iron layer is in the ferrite phase. However, at 1223 K (950°C) the parabolic rate constant of Wu¨stite reduction drops due to the phase transformation of the iron layer from ferrite to austenite. The effect of oxygen partial pressure on the parabolic rate constant of Wu¨stite reduction is negligible when reducing in a gas mixture with a dew point below 283 K (10°C). During oxidation of the Mn alloyed steel, Mn is dissolved in the Wu¨stite scale. Subsequently, during reduction of the Wu¨stite layer, Mn diffuses into the unreduced Wu¨stite. Ultimately, an oxide-free iron layer is obtained at the surface of the Mn alloyed steel, which is beneficial for coating application.

show abstract

Effect of dew point on the surface selective oxidation and subsurface microstructure of TRIP-aided steel

Cited by 49 publications

References 37 publications

Study of Grain Boundary Oxidation of High Alloyed Carbon Steels at Coiling Temperature

Study of Grain Boundary Oxidation of High Alloyed Carbon Steels at Coiling Temperature

Efeito Do Ponto De Orvalho Da Atmosfera Dos Fornos De Recozimento Da CGL Na Qualidade Do Revestimento Ga Em Aço Bake Hardenable

Reduction Kinetics of Wüstite Scale on Pure Iron and Steel Sheets in Ar and H2 Gas Mixture

Contact Info

Product

Resources

About