Ti微合金化Q345D钢中厚板的组织和力学性能

Structure and Mechanical Properties of Medium and Heavy Plate of Ti Microalloyed Q345D Steel

研究了铁水脱硫处理-150 t转炉-RH-保护浇铸-控轧控冷工艺生产的Ti微合金化Q345D钢（/％：0.15C,0.27Si,1.36Mn,0.019Ti,0.011P,0.003S,0.026Als）30 mm ×2 500 mm中板的力学性能、组织和析出物.结果表明,Ti微合金化Q345D钢的抗拉强度≥525 MPa,屈服强度≥390 MPa,延伸率≥29％,-40℃冲击功125 J;该钢组织为珠光体＋铁素体＋少量索氏体,晶粒度为12 ～ 14级;钢中夹杂物主要为MnS和Ti4C2S2,钢中析出物为50 ～250 nm弥散分布的TiN;钢的强度增加主要是TiN细晶强化作用引起的.

The mechanical properties, structure and precipitates of medium plate 30 mm ≥ 2 500 mm of Ti microal- loyed Q345D steel （/% ： 0. 15C, 0. 27Si, 1.36Mn, 0. 019Ti, 0. 011P, 0. 003S, 0. 026Als） produced by hot metal desul- phurizing-150 t converter-RH-shielding casting-control rolling and cooling process have been studied. Results show that of Ti microalloying Q345D steel the tensile strength is ≥525 MPa, yield strength ≥390 MPa, elongation ≥29% and the -40 ℃ impact energy is 125 J; the structure of steel consists of pearlite, ferritc and minor sorbite with grain size grade 12 ~ 14; the main inclusions in steel are MnS and Ti4C2S2, the precipitates in steel are dispersive-distributed 50 -250 nm TiN ; and the increment of strength of steel is mainly caused by fine-grain strengthening of TiN.