摘要
用Gleeble-2000动态热/力模拟机,通过凝固法测定成分(%)为0.61C-0.74Mn-0.18Cr 60Mn钢的高温塑性(断面收缩率),得出60Mn钢存在＞1 300 ℃和925～750 ℃两个高温脆性区.在925～750 ℃温度中,钢中AlN和NbN等氮化物在γ晶界析出,先共析α-相在γ+α区呈网膜状.通过优化工艺,钢中Als量由原来的≤0.015%降到≤0.010%,采用强化VD脱气和保护浇铸使[N]由60×10-6降至40×10-6,过热度由≤50 ℃降至≤35 ℃,比水量由0.40 L/kg降至0.30 L/kg,降低拉矫力并保持矫直前铸坯表面温度≥900 ℃,从而降低了铸坯疏松级别,等轴晶比由优化前的45.7%增至51.3%,内裂发生率由5.2%降至1.7%,铸坯质量显著提高.
the hot plasticity （reduction of area） of steel 60Mn-0.61C, 0.74Mn, 0.18Cr was carried out by Gleeble-2000 dynamic thermo mechanical simulator using solidifying method. It was obtained that there were two low ductility regions at high temperature - more than 1300℃ and 925～750℃. At temperature between 925℃ and 750℃, the nitride AlN and NbN precipitated at γ grainboundary and the proeutectoid α- phase was distributed as net shaped in γ＋α two phase region. With optimized process the Als in steel decreased to ≤0.010% from original ≤0.015%, by intensifying VD degassing and shielding casting practice the [N] decreased to 40 × 10^-6 from 60 × 10^-6 , and with overheating temperature of molten steel decreasing to ≤35℃ from ≤50℃, water ratio decreasing to 0.30 L/kg from 0.40 L/kg, lowering cast straightening force and keeping surface temperature of billet ≥900℃ before straightening, the rating of billet porosity decreased, the equiaxed zone ratio increased to 51.3% from 45.7% before optimized and internal crack ratio decreased to 1.7% from 5.2%, the quality of billet obviously improved.
出处
《特殊钢》
北大核心
2005年第6期54-56,共3页
Special Steel
