The rolling production of metal thin strips,especially the production of stainless steel and copper thin strips with high yield strength,due to the limitation of the minimum rolling thickness,multi roll mills with sma...The rolling production of metal thin strips,especially the production of stainless steel and copper thin strips with high yield strength,due to the limitation of the minimum rolling thickness,multi roll mills with small working roll diameter are mostly used,and the 20 roll mill is the most common.Aiming at the problem that the actual tension of some 20 high rolling mills with long service time and low assembly accuracy has a large deviation from the set tension and is not accurate enough,this paper first designs the tension calibration device of the low precision 20 high rolling mill.Secondly,the calibration principle of the tension calibration device designed in this paper is described.Then,according to the calibration principle and specific implementation scheme,the actual tension tact of the strip steel is comprehensively determined,and the mapping relationship between the set tension tset and the actual tension tact of the 20 high mill is established,so as to improve the tension control accuracy of the 20 high mill and ensure the shape quality of the strip steel.展开更多
Compared with the original GCr15 bearing steel,TiN inclusions are greatly reduced by the effect of Mg addition,and many different types of non-metallic Mg-containing inclusions were observed in Mg-treated GCr15 bearin...Compared with the original GCr15 bearing steel,TiN inclusions are greatly reduced by the effect of Mg addition,and many different types of non-metallic Mg-containing inclusions were observed in Mg-treated GCr15 bearing steel which includes MgO,MgS·MnS,MgO–MgS·MnS,MgAl_(2)O_(4)–MgS·MnS,MgO–TiN,MgS·MnS–TiN,and MgO–MgS·MnS–TiN.The inclusion size distribution based on automatic inclusion analysis software shows that the number of inclusion with the size ranging from 1 to 3μm increases obviously because a large amount of MgO,MgS·MnS,TiN inclusions containing Mg with smaller sizes are massively generated.In situ observation on the experimental steel by high-temperature confocal laser scanning microscopy confirms that MgO can provide nucleation sites for TiN.In addition,the MgS·MnS and MgO–MgS·MnS inclusions can also provide positions for the nucleation of TiN.Thermodynamic calculations indicate that after Mg addition to liquid steel,a large number of fine MgO inclusions are generated in the liquid steel because of the strong reactivity of Mg and O.At the same time,MgS precedes TiN precipitates in the solid–liquid two-phase region;thus,MgO and MgS·MnS can provide sites for TiN nucleation.At last,two possible formation pathways for the above various TiN inclusions containing Mg are discussed.展开更多
文摘The rolling production of metal thin strips,especially the production of stainless steel and copper thin strips with high yield strength,due to the limitation of the minimum rolling thickness,multi roll mills with small working roll diameter are mostly used,and the 20 roll mill is the most common.Aiming at the problem that the actual tension of some 20 high rolling mills with long service time and low assembly accuracy has a large deviation from the set tension and is not accurate enough,this paper first designs the tension calibration device of the low precision 20 high rolling mill.Secondly,the calibration principle of the tension calibration device designed in this paper is described.Then,according to the calibration principle and specific implementation scheme,the actual tension tact of the strip steel is comprehensively determined,and the mapping relationship between the set tension tset and the actual tension tact of the 20 high mill is established,so as to improve the tension control accuracy of the 20 high mill and ensure the shape quality of the strip steel.
基金The authors are grateful to the National Natural Science Foundation of China(Grant No.51874170)for supporting this work.
文摘Compared with the original GCr15 bearing steel,TiN inclusions are greatly reduced by the effect of Mg addition,and many different types of non-metallic Mg-containing inclusions were observed in Mg-treated GCr15 bearing steel which includes MgO,MgS·MnS,MgO–MgS·MnS,MgAl_(2)O_(4)–MgS·MnS,MgO–TiN,MgS·MnS–TiN,and MgO–MgS·MnS–TiN.The inclusion size distribution based on automatic inclusion analysis software shows that the number of inclusion with the size ranging from 1 to 3μm increases obviously because a large amount of MgO,MgS·MnS,TiN inclusions containing Mg with smaller sizes are massively generated.In situ observation on the experimental steel by high-temperature confocal laser scanning microscopy confirms that MgO can provide nucleation sites for TiN.In addition,the MgS·MnS and MgO–MgS·MnS inclusions can also provide positions for the nucleation of TiN.Thermodynamic calculations indicate that after Mg addition to liquid steel,a large number of fine MgO inclusions are generated in the liquid steel because of the strong reactivity of Mg and O.At the same time,MgS precedes TiN precipitates in the solid–liquid two-phase region;thus,MgO and MgS·MnS can provide sites for TiN nucleation.At last,two possible formation pathways for the above various TiN inclusions containing Mg are discussed.
