HB450低合金超高强耐磨钢回火过程中的组织性能演变

  利用透射电镜（TEM）、扫描电镜（SEM）等试验方法，研究了新型低成本HB450低合金超高强耐磨钢在不同回火条件下组织和性能演变规律，并分析了其强韧变化机制。结果表明：回火对试验钢的硬度和强度均有较大影响。在200~250℃回火，试验钢表现出良好的强韧性配合，满足国标工程机械用高强度耐磨板GB/T24186—2009中NM450级别要求；在250℃回火时，试验钢出现硬化迹象。透射电镜分析表明，在该温度下回火，析出物中除了有大量弥散分布的ε 碳化物外，还出现了少量30~50nm的（Nb，Ti）（C，N）粒子，该2类粒子对试验钢的强化起着较大的作用。

Microstructure and Properties Evolution of HB450 Ultra-High Strength Low-Alloy Abrasion Resistant Steel During Tempering

Effects of tempering on microstructure and mechanical properties of new HB450 low alloy abrasion resistant steel were investigated by transmission electron microscopy (TEM) and utilizing scanning electron microscopy (SEM), and the mechanisms of reinforcement in strength and toughness were also analyzed. Results show that tempering has considerable influence on both hardness and strength. When tempering temperature is from 200℃ to 250℃, the mechanical properties meet the demands of NM450 at GB /T 24186—2009. The hardening phenomenon occurs at the tempering temperature of 250℃. TEM analyses shows that besides the precipitate of ε carbide, some of the 30 to 50nm（Nb,Ti）（C,N） particles also precipitate in the original austenite grain boundaries and martensite lath beam, which played a large role on strengthening for the test steel.