eutectoid ferrite

The pre eutectoid ferrite transformation initiated at the original austenite grain boundaries and formed a net structure.

先共析铁素体沿原始奥氏体晶粒边界生长，形成网状结构。

By Cr microalloying, the fore eutectoid ferrite eduction is restrained, the distance between rows of pearlite is decreased, then the tensile strength, section shrinkage and drawing property of high carbon steel wire rod is obviously raised and improved.

高碳钢中加入的铬元素抑制先共析铁素体析出，减小珠光体片层间距，可明显提高抗拉强度，提高断面收缩率，改善线材的拉拔性能。

The experimental results show that the critical cooling rate of pro-eutectoid ferrite is 0. 1 5 ℃/ s, and the structure of complete granular bainite can be obtained with a cooling rate from 0. 15 ℃/ s to 1 ℃/ s.

试验结果表明，本试验用钢不发生先共析铁素体析出的临界冷却速度为0.15℃／s；冷却速度在0.15～1.00℃／s范围时可得到全部粒状贝氏体组织；

The critical cooling rate that does not occur pre-eutectoid ferrite is 0.012 ℃/ s.

不发生先共析铁素体转变的临界冷却速度为0012℃/s。

It is found that the pre eutectoid ferrite is retarded by addition of B element and the segregation of P and S on the grain boundary is restrained.

研究中发现，在连铸过程中，硼添加到钢中，显著推迟了先共析铁素体的析出，抑制了P，S等元素在晶界的偏聚。

The results show that the microstructure of the steel obtained after cooling is proeutectoid ferrite, eutectoid ferrite from the austenite, a little carbide-free bainite, granular bainite and martensite.

结果表明，该钢在冷却过程中组织均为未溶的先共析铁素体、从奥氏体中析出的共析铁素体、少量的无碳化物贝氏体、粒状贝氏体和马氏体。