一引言硼对低、中碳合金结构钢韧性的影响已有不少研究.硼既可通过固溶于基体或析出为硼相而直接影响韧性,又可通过提高淬透性、改变晶粒大小而间接影响韧性,由于因素比较复杂,因此,所得结果也不尽一致.一般认为,从提高淬透性来看,最佳含硼量范围约在0.0015～0.0025%左右.由于改善了淬透性,淬火后无铁素体,回火后具有较低的脆性转化温度.不少研究指出,当钢中酸溶硼>0.0030%时,在 I. INTRODUCTION There has been much research on the effect of boron on the ductility of low and medium carbon structural steel.Brite can directly affect the toughness by solid solution in the matrix or precipitated as boron phase and can also change the grain size by increasing the hardenability, But indirectly affect the toughness, due to more complex factors, so the results are not uniform.It is generally believed that from the perspective of improving hardenability, the optimum range of boron content of about 0.0015 ~ 0.0025% due to improved hardenability , After quenching without ferrite, after tempering has a lower brittle transition temperature.Many studies have shown that when the steel acid soluble boron> 0.0030%, at