CAJ | 학술논문

研究了高强度含铜钢HSLA80和HSLA100奥氏体连续冷却转变产物的强度和韧性随冷却速率的变化规律,探讨了连续冷却过程中形成的Cu沉淀的特征和熟化规律.在Gleeble3800热模拟试验机上进行0.1℃·s-1至20℃·s-1的连续冷却实验,利用扫描电镜和透射电镜分析了显微组织和Cu沉淀.结果表明,随冷却速率提高,HSLA80的连续冷却转变组织由多边形铁素体向块状铁素体和贝氏体转变,在冷速0.1~1℃·s-1范围内Cu发生沉淀,两者综合作用造成随冷却速率提高钢的硬度分阶段变化,而韧性逐渐提高；HSLA100的连续冷却转变组织以贝氏体为主,且不发生Cu的沉淀,随冷却速率提高钢的硬度基本保持不变,但韧性发生剧烈变化.连续冷却过程中形成的Cu沉淀在等温过程中的熟化符合Ostwald熟化规律,半径随时效时间t1/3变化.
연구료고강도함동강HSLA80화HSLA100오씨체련속냉각전변산물적강도화인성수냉각속솔적변화규률,탐토료련속냉각과정중형성적Cu침정적특정화숙화규률.재Gleeble3800열모의시험궤상진행0.1℃·s-1지20℃·s-1적련속냉각실험,이용소묘전경화투사전경분석료현미조직화Cu침정.결과표명,수냉각속솔제고,HSLA80적련속냉각전변조직유다변형철소체향괴상철소체화패씨체전변,재랭속0.1~1℃·s-1범위내Cu발생침정,량자종합작용조성수냉각속솔제고강적경도분계단변화,이인성축점제고；HSLA100적련속냉각전변조직이패씨체위주,차불발생Cu적침정,수냉각속솔제고강적경도기본보지불변,단인성발생극렬변화.련속냉각과정중형성적Cu침정재등온과정중적숙화부합Ostwald숙화규률,반경수시효시간t1/3변화.
The effects of cooling rate on the strength and toughness of austenite decomposition products in high strength Cu-bearing steels HSLA80 and HSLA100 were investigated during continuous cooling. Characterization and ripening of Cu precipitates formed dur-ing continuous cooling were discussed. Continuous cooling experiments from 0.1 to 20℃·s-1 were carried out by Gleeble thermo-simu-lation. Microstructures and Cu precipitates were observed by scanning electron microscopy and transmission electron microscopy. It is found that the microstructure of austenite decomposition products in HSLA80 steel changes from polygonal ferrite to granular ferrite and bainite with increasing cooling rate. Cu precipitation occurs during continuous cooling within the cooling rate of 0.1 to 1℃·s-1 . Due to the microstructure and Cu precipitates, the hardness changes by stages and the toughness increases gradually as the cooling rate in-creases. The microstructure of austenite decomposition products in HSLA100 steel is mainly bainite and Cu precipitation does not oc-cur, so that the hardness does not change on the whole, but the toughness varies dramatically with increasing cooling rate. Ripening of Cu precipitates formed during continuous cooling obeys the Ostwald law. The radius of Cu precipitates increases with aging time t1/3 .