微合金化高碳77B盘条钢的组织与性能

Microstructure and Properties of Microalloying High-carbon 77B Steel Rods

利用热模拟试验机、万能试验机和光学显微镜对不同微合金化处理后高碳77B盘条钢的变形温度和冷却速度进行了研究。实验结果表明:钒微合金化和钒氮微合金化均能细化珠光体组织,提高77B钢的强度,且钒氮微合金化的作用更大,但也更易形成先共析铁素体,钒和氮的添加上限分别约为0.08%和0.012%;77B盘条钢中单独加铬对抗拉强度有小幅提升,但钒、氮、铬同时加入时会极大恶化塑性,铬合金化不是77B盘条的强化方向。钒氮微合金化77B钢的最佳生产工艺为:变形温度900～920℃;终冷速度1～2℃/s。

The deformation temperature and cooling rate of different microalloying high carbon 77B steel rods were studied by thermal simulator, universal test machine and optical microscope. The results show that vanadium microalloying and vanadium nitrogen microalloying can both refine pearlite structure and improve the strength of 77B steel rods, and vanadium nitrogen microalloying is more effective, but it is easier to form pre eutectoid ferrite. The upper limit of adding vanadium and nitrogen is about 0.08% and 0.012%, respectively. The tensile strength of 77B wire rods is increased slightly by adding chromium alone. However, when vanadium, nitrogen and chromium combined addition, it will greatly deteriorate plasticity. Chromium alloying is not the strengthening direction of 77B wire rods. The best test production process of vanadium nitrogen microalloyed 77B steel rods is rolling at 900-920 ℃ with the cooling speed at 1-2 ℃/s.