Study On Galvanizability Of Medium-Mn Steel And Microstructural Development Of Zn-coating During Austenitizing

Nowadays,automotive light-weighting has become an important trend in automobile development,and advanced high-strength steel is the optimal choice to meet the light weight and safety of automobile Medium-Mn steels become a focus because of the combination of high-strength and high ductility.In addition,the body anti-corrosion is also an important factor to ensure the safety of automobile,and the hot dip galvanizing technology as a kind of mature and cheap coating anticorrosive technology has become a better choice for automotive steel corrosion treatment.In order to combine the high strength steel with hot dip galvanizing coating technology to achieve the manufacture of advanced high-strength steel with better anti-corrosion performance,this paper has carried out some research on hot dip galvanizing coating and its evolution during hot-stamping process of a newly designed medium-Mn steel.In this paper,the newly designed medium-Mn steel steel is studied,through the compare of the samples in different annealing atmosphere during hot dip galvanizing,an appropriate annealing atmosphere for the medium-Mn steel is obtained,this paper also studied the heating process and Fe-Al inhibition layer on the influence of coating organization after austenitizing,the main conclusions are as follows:(1)With the increase of dew point,the oxygen partial pressure increases,the oxidation form is changed from the external oxidation to the internal oxidation,the surface quality of the hot-dip sample is improved.With the increase of hydrogen content,the reducing of atmosphere is enhanced and the surface quality is improved,but with the further increase of hydrogen content,the oxygen partial pressure in the atmosphere decreases,the coating quality decreases;(2)Through the electron probe surface scanning experiment,the distribution of elements in different annealing atmosphere samples has compared,it indicate the effect of annealing atmosphere on the hot-dip of medium manganese steel;(3)Accoding to the experimental results in this paper,the optimal annealing atmosphere for the medium manganese steel is dew point-5? and 10%hydrogen content;(4)The rapid heating process can inhibit the occurrence of sandelin effect in siliconcontaining manganese steel,and control the thickness of the coating;(5)By the austenitic simulation of different hot dip galvanizing sample,the influence of the Fe-Al inhibition layer on the evolution of coating was compared,and the continuous Fe-Al inhibition layer had a certain inhibitory effect on the growth of the Fe-Zn layer,and the coating thickness was controlled.