CAJ | 학술논문

以C－Si－Mn系TRIP钢成分为基础，设计了四种不同Si和Mn含量的合金成分，并采用不同两相区奥氏体化温度的淬火—配分（ Q&P）工艺进行处理，得到了兼具高强度和高塑性的Q&P钢。其中，当奥氏体化温度为820℃时，0．18C－1．8Si－2．2Mn（质量分数，％）钢和0．18 C－1．8 Si －2．5 Mn 钢在抗拉强度达到1000 MPa 以上的同时断后延伸率仍不低于20％，显示了极佳的强塑性结合。利用SEM和XRD等对热处理材料的显微组织进行了表征，结果显示，其显微组织为铁素体、板条马氏体和一定量的残余奥氏体，残余奥氏体多呈块状且被铁素体所包围，且奥氏体化温度为820℃时，材料中的残余奥氏体含量和平均碳浓度均较高。更多且稳定的残余奥氏体在变形过程中发生TRIP效应，可以在不显著降低材料强度的情况下更有效地改善材料的塑性，这也是四种试验用钢经820℃的Q&P工艺处理后显示出更佳强塑性结合的主要原因。
이C－Si－Mn계TRIP강성분위기출，설계료사충불동Si화Mn함량적합금성분，병채용불동량상구오씨체화온도적쉬화—배분（ Q&P）공예진행처리，득도료겸구고강도화고소성적Q&P강。기중，당오씨체화온도위820℃시，0．18C－1．8Si－2．2Mn（질량분수，％）강화0．18 C－1．8 Si －2．5 Mn 강재항랍강도체도1000 MPa 이상적동시단후연신솔잉불저우20％，현시료겁가적강소성결합。이용SEM화XRD등대열처리재료적현미조직진행료표정，결과현시，기현미조직위철소체、판조마씨체화일정량적잔여오씨체，잔여오씨체다정괴상차피철소체소포위，차오씨체화온도위820℃시，재료중적잔여오씨체함량화평균탄농도균교고。경다차은정적잔여오씨체재변형과정중발생TRIP효응，가이재불현저강저재료강도적정황하경유효지개선재료적소성，저야시사충시험용강경820℃적Q&P공예처리후현시출경가강소성결합적주요원인。
Based on C -Si-Mn TRIP steel, four types of steels with different contents of Si and Mn were designed and subjected to quenching and partitioning ( Q&P) processes with variable austenizing temperatures .The as-treated steels exhibited good combination of high strength and substantial elongation .Particularly, with austenizing at 820℃, 0.18C-1.8Si-2.2Mn (%) steel and 0.18C -1.8Si -2.5Mn (%) steel possessed high elongation ( more than 20%) with the tensile strength over 1 000 MPa.The microstructures of the as-treated steels were observed by SEM , and the volume fraction and carbon content of retained austenite were quantified by XRD .As a result , the designed Q&P steels contained a multi-phase microstructure including ferrite , lath martensite and retained austenite , the volume fraction and carbon content of which is higher in those steels treated by Q&P processes with austenizing at 820 ℃.By TRIP effect during the deformation , more retained austenite with better stability can more effectively improve the formability of steels with slightly decreasing the strength , contributing to a better performance .