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为了推导出线材与棒钢轧制中宽展率的通用简化计算公式,用方形—椭圆、圆—椭圆、方形—菱形与菱形—菱形孔型系对钢坯进行了热轧试验研究。此外,还研究了这种轧材的无应力侧表面的外形和各种几何因素与宽展率的关系。宽展侧表面(无应力侧表面)的外形在四种孔型系中是不同的:在方形—椭圆孔型中,近似于直线;在圆形—椭圆孔型中,呈双圆弧,其半径比坯料的大;在方形—菱形孔型中,轧制前后侧表面的夹角相近似;在菱形—菱形孔型中,轧后侧表面的夹角比轧前的稍小一些。对最大接触宽度投影计算值和实测值的比较表明两者非常一致。采用上述四种孔型系统时,轧材的宽展率可以用如下简化公式表示:宽展率=B_1-B_0/B_0=αL_(dm)/B_0+0.5H_0·F_H/F_0式中 B_0、B_1—轧制前后的轧件宽度;H_0—轧制前的坯料高度;L_(dm)—接触弧的平均投影长度;F_H/F_0—坯料断面压缩率;α—系数(=0.83)。这是一个通用的、简单而有效的、精确的公式。
In order to derive a general simplified formula for calculating the wide spread ratio of wire rod and rod rolling, hot rolling tests on the billet were carried out with square-ellipse, circle-ellipse, square-diamond and diamond-diamond. In addition, the relationship between the shape of the unstressed side surface of this rolled material and various geometric factors and the wide spread ratio has also been studied. The profile of the widened side surface (unstressed side surface) is different for the four pore types: in a square-elliptical well, it approximates a straight line; in a circular-elliptical well, a double circular arc The radius is larger than that of the blank; in the square-rhombic hole type, the included angles of the side surfaces before and after rolling are similar; in the rhombus-rhombic hole type, the included angle of the back side of the rolling is slightly smaller than that before the rolling. Comparisons of the calculated and measured values for the maximum contact width show that the two are very consistent. When using the above four kinds of hole type system, the wide spread rate of the rolled material can be expressed as the following simplified formula: Wide spread = B_1-B_0 / B_0 = αL_ (dm) /B_0+0.5H_0_F_H/F_0 Where B_0, B_1 - rolling width before and after rolling; H_0 - billet height before rolling; L_ (dm) - average projected length of the contact arc; F_H / F_0 - billet section reduction; α coefficient (= 0.83). This is a universal, simple and effective, accurate formula.