低硅含铝TRIP钢残余奥氏体变形过程中稳定性研究EI北大核心CSCD

采用预拉伸实验对低硅含铝TRIP钢变形过程中残余奥氏体的演变规律进行研究,建立残余奥氏体变形过程中稳定性与加工硬化指数n之间的对应关系,在此基础上通过设计不同热处理工艺,获得具有不同初始残余奥氏体特性的TRIP钢以及具有不同组织构成的TRIP钢,并分析了TRIP钢的残余奥氏体稳定性。结果表明:TRIP钢中的残余奥氏体随着变形的深入,稳定性逐渐增加;残余奥氏体越稳定,TRIP钢的瞬时加工硬化值越稳定(n值越稳定);随着初始碳含量的增加,残余奥氏体在变形过程中的稳定性也随之提高。在变形过程中,残余奥氏体的稳定性受残余奥氏体碳含量,分布以及周围相等因素的共同影响。     

热轧TRIP钢残余奥氏体及其稳定性研究

采用X射线衍射(XRD)、透射电镜(TEM)和拉伸实验等方法,研究三种工艺制备的热轧TRIP钢残余奥氏体及其碳含量和稳定性.结果显示:贝氏体区停留时间对残余奥氏体量影响较大,当在贝氏体区模拟卷取时,残余奥氏体量最多;适当的增加弛豫时间,会增加最终组织中残余奥氏体的碳含量;残奥碳含量,还有残余奥氏体的形状和晶粒大小及周围...     

热轧TRIP钢的加工工艺与残余奥氏体形成的关系

低合金TRIP钢的显微组织中残余奥氏体使其具有优良的强度和延性组合。分别介绍了热轧TRIP钢在奥氏体再结晶区、未再结晶区以及临界区变形对残余奥氏体形成的影响。分析了输送台上的冷却和卷取温度对残余奥氏体形成的影响。对低合金TRIP钢残余奥氏体的形成等物理冶金学的研究可以促进该类合金的开发和推广应用。     

贝氏体区等温时间对TRIP钢残奥及力学性能影响

为研究贝氏体区等温时间对热轧TRIP钢残余奥氏体和力学性能的影响,采用金相显微镜、X射线衍射、拉伸实验等方法对3种不同贝氏体区等温时间下制备的热轧TRIP钢进行分析.结果表明:随着贝氏体等温时间的延长,残余奥氏体量减少而残余奥氏体碳含量增加,残余奥氏体晶粒尺寸及残余奥氏体形貌变化不大;热轧TRIP钢的力学性能随着贝氏体...     

TRIP钢中奥氏体的力学稳定性研究

采用分阶段拉伸、XRD、EBSD、SEM、TEM等实验手段,研究了TRIP钢奥氏体的力学稳定性.结果表明:拉伸变形初期奥氏体转变较快,拉伸变形后期奥氏体转变较慢;奥氏体的含碳量不同,在相同的拉伸变形阶段奥氏体转化率的增加速率不同;处于铁素体、贝氏体晶界或者相界面1um以上大颗粒奥氏体几乎在变形初期就全部发生相变,而晶粒...     

含磷低硅TRIP 钢快速退火组织演变行为研究

通过实验室热处理模拟实验,对含磷低硅transformation induced plasticity(TRIP)钢快速退火过程中各个阶段的组织演变行为进行研究,主要研究了不同退火温度对各个阶段组织组成的影响。通过添加P元素降低钢中的Si含量,可改善表面质量,解决镀锌问题,且P价格低廉,成本降低。结果表明:最终组织中的铁素体量降低,贝氏体和马氏体混合物的量增加。经X射线衍射(XRD)分析可知,残余奥氏体量增加,由750℃退火时的12.7%增加至790℃退火时的14.9%。     

双相钢中的残余奥氏体

研究了热－机械处理中各种因素对双相钢中的残余奥氏体的影响，发现：双相区热处理前的冷加工使奥氏体成核密度提高，且使残余奥氏体分布均匀和含量增加；微观结构的观察表明，空冷过程中奥氏体颗粒在不断缩小，颗粒的尺寸效应和碳原子向奥氏体中偏聚均使奥氏体变得稳定。因此，恰当地控制冷加工量、冷却速度、加热温度和时间，可使双相钢含有数量和稳定度都合适的残余奥氏体。此外还发现，从双相区温度空冷所得马氏体必须经低温短时     

预奥氏体化对中Mn TRIP钢组织及力学性能的影响

为了提高钢的综合力学性能,用盐浴法对中Mn TRIP钢进行了热处理.采用SEM、TEM、XRD和拉伸测试研究了预奥氏体化处理对中Mn TRIP钢显微组织及力学性能的影响.实验结果表明:全马氏体冷轧态组织经两相区退火处理后,会析出大量渗碳体颗粒,随着退火时间延长,渗碳体颗粒逐渐溶解,马氏体组织逐渐转变为奥氏体和铁素体双相片层状组织;而在两相区退火处理前添加两相区预奥氏体化处理后,渗碳体析出被有效抑制,双相片层组织迅速形成;相比于常规两相区退火处理,预奥氏体化处理能够提高组织中残余奥氏体体积分数和综合力学性能.     

滚动轴承钢中残余奥氏体量的测定

分别采用磁性法、金相方法和X射线衍射法测量了GCr15轴承钢中的残余奥氏体含量,探讨了残余奥氏体含量对GCr15轴承钢使用寿命的影响.结果表明,磁性法测量GCr15轴承钢中残余奥氏体量快捷、准确,易于实现产品生产中的在线快速检测,轴承钢中残余奥氏体对轴承运行过程中疲劳寿命的影响,必须结合应力形态、分布、运行状态及诱发马...     

中锰Q&P钢残余奥氏体的稳定性及其TRIP效应

通过单向拉伸及平面应变实验研究了Mn含量为7%的中锰淬火-配分(QP)钢残余奥氏体的机械稳定性,利用X射线衍射仪(XRD)测定试验钢残余奥氏体的含量,通过观察试验钢的拉伸曲线及扫描电镜(SEM)、透射电镜(TEM)照片,分析变形前后的微观组织,研究中锰QP钢的变形机制。结果表明:应力状态对残余奥氏体稳定性有较大的影响,平面应变更有利于相变诱导塑性(TRIP)效应的发挥;中锰QP钢的拉伸变形特征是由超细晶硬化机制和TRIP效应相互作用产生的,通过微观组织观察发现中锰QP钢的塑性变形主要是残余奥氏体的TRIP效应,其中薄膜状的残余奥氏体的稳定性最高。     

Quantitative Mossbauer Study on Retained Austenite and Carbide in High Speed Steel

The retained austenite in high speed steel oftwo different heat treatment regimes wasquantitatively,determined by transmissionMssbauer spectroscopy (TMS),backscatteringX-ray geometry,Mossbauer spectroscopy (BXMS)and X-ray diffraction technique.The results meas-ured by these methods were in agreement with eachother.It was demonstrated that the concentrationof carbides in high speed steel could be measured bytransmission Mossbauer spectroscopy or Mossbau-er spectroscopy in backscattering X-ray geometryaccurately.     

GCr15钢等温转变组织中的残余奥氏体

本文采用SCAY-1型数字式残余奥氏体测定仪测量了试样的残余奥氏体量,揭示了等温时间与残余奥氏体含量之间的关系,并且用JEM-100CX透射电子显微镜观察了残余奥氏体的形貌,发现残余奥氏体大多以层片状存在于贝氏体/贝氏体(B/B)边界或马氏体/贝氏体(M/B)边界上。     

Mechanical and Transformation Behaviors of a C-Mn-Si-Al-Cr TRIP Steel under Stress

Transformation induced plasticity （TRIP） steels combine high strength and excellent ductility, making them suited for application in crash-relevant parts in the automotive industry. However, the high Si contents in the conventional TRIP steel will generate surface defects on the hot rolled strip, which is difficult to process in continuous galvanizing lines. In order to solve the above problem the TRIP steel with the addition of Al replacing majority of Si was designed. In the present paper, the volume fraction of various phases in a C-Mn-Si-Al-Cr TRIP steel was determined by metallographic examination and X-ray diffraction analysis, and the multi-phase microstructures were characterized using an atomic force microscope based on their height difference. Tensile tests were performed at different temperatures ranging from -40℃ to 90℃. The results show that transition temperature Ms^σ in the present TRIP steel cannot be determined due to its lower volume fraction of retained austenite, different from the conventional TRIP steel. While the yield stress and tensile strength at different temperatures are higher than those of the conventional TRIP steel, which is attributed to the addition of Cr. In order to evaluate the effect of martensitic transformation on the total elongation, the sample without retained austenite obtained by quenching in liquid nitrogen was carried out under tensile test. The results indicate that the elongation of the original sample containing 9% retained austenite is about 20% higher than that of the sample quenched in liquid nitrogen, which demonstrates that the retained austenite plays an important role in improving the elongation of the TRIP steel.     

Research on Retained Austenite for Advanced Aluminum-containing Hot-rolled TRIP Steel

1. IntroductionTransformation induced plasticity (TRIP) steels havebeen well known for the well balanced comprehen-sive mechanical properties with high strength and highplasticity[1~13] and can be used to press form thevehicle's parts to increase the safety and save the oilby increasing the strength and reducing the weight forautomobile[14~17]. Silicon is one of the common andcheap elements to be added into the steel to increase re-tained austenite stability[18,19]. However, silicon tendsfor…