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从实验结果证明,硼对珠光体的成核及成长是有影响的;在亚共析钢中硼促使珠光体的开始形成时间推迟,增长了珠光体成核的孕育期,但对成核率与时间的关系,在近于A_1温度(700℃)时,略为加速,而在珠光体转变速度最大的温度(650℃)时却没有影响。在共析钢中硼同样的使珠光体形成开始时间延迟,但对成核率与时间的关系没有改变,因此很可能硼促使奥氏体晶界能降低,珠光体得不到足够的能量成核,因而增加了奥氏作的稳定度。硼有加速珠光体成长率的作用,无论在亚共析或共析钢中皆有同样的现象产生。因此我们认为在珠光体形成温度范围内,硼虽使奥氏体转变开始时间推迟,但不影响转变终了时间的原因,是由于珠光体成长率加速所致。
From the experimental results, it is proved that boron affects the nucleation and growth of pearlite. In the hypoeutectoid steel, boron causes the pearlite to start to defer and the growth period of pearlite nucleation increases, but the nucleation rate The relationship with time is slightly accelerated near A_1 (700 ° C) and unaffected at 650 ° C (pearlite transformation). In eutectoid steels, boron also delayed the onset of pearlite formation, but did not change the relationship between nucleation rate and time, so it is probable that boron promotes the reduction of austenite grain boundaries and does not provide enough energy for pearlite nucleation , Thus increasing the stability of austenite. Boron accelerates the growth rate of pearlite and produces the same phenomenon in both sub-eutectoid and eutectoid steels. Therefore, we believe that the reason for the delay in the beginning of austenite transformation in the range of pearlite formation temperature is that boron does not affect the end-of-transition time due to the accelerated pearlite growth rate.