Effect of Rare Earth Elements on Growth Dynamics of Austenite in 60CrMnMo Steel

The growth dynamics of austenite grains was investigated in 60CrMnMo steel with different RE elements. The results show that austenite grains of 60CrMnMo steel can be refined and their growth can be restrained by adding a certain amount of RE. From the experimental results, the values of n and Q were evaluated.

Effect of Rare Earths on Tensile Behavior of Hot Roller Steel 60CrMnMo and Estimation of Roll's Fati

The effect of rare earth(RE) on tensile behavior of hot roller steel 60CrMnMo was investigated at the temperature when roll served The roll′s fatigue at 500 ℃ was estimated The results show that elongation δ of hot roller steel 60CrMnMo can be increased by adding RE It is possible to estimate the fatigue life with tensile behavior of hot roller steel 60CrMnMo

Effect of Rare Earth Elements on Austenite Growth Dynamics of Steel 9Cr2Mo

The growth dynamics of austenite grain was investigated in steel 9Cr2 Mo with different rare earth(RE)element addition.The results show that austenite grains of steel 9Cr2 Mo can be refined and their growth can be restrained by adding a certain amount of RE.According to the results,the n and Q were calculated and the mechanism of the refinement of austenite grains was discussed.

Effect of Rare Earth Elements on Low Frequency Fatigue Cyclic Softening of Hot Rolled Steel 60CrMnMo at High Temperature

The effect of rare earth (RE) on cyclic softening of low frequency fatigue of the hot rolled steel 60CrMnMo at high temperature was investigated. The hardness of specimens before thermal fatigue test and being cycled 180 times from room temperature to 650℃ was compared. The results show that by adding a certain amount of RE in steel 60CrMnMo, the cyclic softening during low frequency fatigue test at high temperature can be restrained considerly. The carbide particles were refined during tempering treatment and the agglomeration and growth of carbide particles can be obstructed during thermal cycle.

Effect of Rare Earth Elements on Low Frequency Fatigue of Hot Rolled Steel 60CrMnMo at High Temperature

The effect of rare earth(RE) on low frequency high temperature fatigue strength of hot rolled steel 60CrMnMo was investigated. The results show that by adding a certain amount of RE in steel 60CrMnMo, its serviceable life during low frequency fatigue test at high temperature can be improved.The number of cycles for fracture was increased by 18.5%～28.8%. The number of large inclusion particleswas reduced and the composition of inclusions and their shape were changed as well. The strip distances on fatigue fracture surface were decreased. It is concluded that the optimum amount of RE addtion is about 0.05 wt%～0. 10 wt%.

稀土深层渗碳钢的研究

研究了稀土深层渗碳钢 2 0Cr2Mn2MoRE奥氏体晶粒长大动力学、渗层组织和力学性能 ,并与2 0Cr2Mn2Mo钢进行了比较。结果表明 :钢中加入稀土元素可显著抑制奥氏体晶粒长大 ,改善渗层组织 。

稀土对低合金耐磨铸钢铸态显微组织的影响

针对未添加稀土和添加不同量La、Ce稀土的低合金耐磨铸钢铸态试样,采用金相显微镜、QUANTA-400环境扫描电镜和JEM-2100透射电镜对其铸态组织、微观亚结构及原始奥氏体晶粒大小进行观察分析,探讨稀土的作用机理。结果表明,未添加稀土时,试验钢的铸态组织为粒状贝氏体,当La、Ce稀土总量为0.0092%时,有少量下贝氏体出现,随稀土含量增加到0.0320%,下贝氏体量增多,并且有板条马氏体出现;透射电镜观察表明,添加稀土可以增大铸态组织中的位错密度、细化试验钢的原始奥氏体晶粒,并使晶粒也更加均匀。

稀土深层渗碳钢晶粒长大及组织遗传研究

通过稀土元素对深层渗碳钢奥氏体晶粒长大倾向的研究,探讨了深层渗碳钢组织遗传的特点,结果表明:稀土元素可细化奥氏体晶粒,从而可以抑制深层渗碳钢的组织遗传,为深层渗碳钢的组织遗传问题提供一些资料。

稀土对不同尺寸微合金钢连铸坯奥氏体化行为的影响

以加与未加稀土的低碳微合金连铸钢坯为研究对象,分别截取心部不同尺寸的试样,根据现场加热制度进行加热处理。通过ICP测定试样的铌、钛含量,采用激光共焦显微镜分析奥氏体原始组织,分析试样尺寸、稀土对奥氏体化行为的影响规律。结果表明,小尺寸试样比大尺寸试样Nb、Ti含量高,而加入稀土对铌、钛的固溶度无明显影响;加入稀土可以改善奥氏体晶粒分布的均匀性、细化晶粒尺寸,对加稀土的大尺寸试样影响显著,其中晶粒尺寸小于30μm的占55.29%,30～60μm的占39.65%,其余尺寸很少。

稀土含量对TRIP/TWIP钢晶粒及晶界特征的影响

利用XRD和EBSD分析稀土含量对TRIP/TWIP高锰钢相组成、晶粒及晶界特征的影响。结果表明,试验钢变形前组织以γ奥氏体为主,还有部分ε马氏体,经过塑性变形后,组织中还观察到少量α马氏体;随着稀土含量的增加,奥氏体转变为马氏体的量有所增加,表明稀土元素促进了试验钢的TRIP效应。此外,稀土元素的添加细化了试验钢中奥氏体晶粒,减少了小角度晶界数量而增加了大角度晶界数量,尤其是取向差为60°左右的大角度晶界;同时,稀土元素的添加也促进了低Σ值重位点阵(CSL)晶界特别是Σ3晶界的形成。

稀土Ce对BT80s-5Cr油井管钢组织及第二相析出的影响

通过加入不同含量的稀土Ce,研究了稀土Ce对BT80s-5Cr油井管钢组织及第二相析出的影响。采用金相显微镜对淬火后原奥氏体晶粒度进行了分析;利用SEM、XRD、TEM对热处理后的微观组织和第二相进行了观察及分析。结果表明,试验钢经900℃保温50 min水淬后,随着稀土Ce含量从0增加至0.012%,原始奥氏体晶粒平均尺寸由14.21μm下降到了11.06μm,稀土Ce含量为0.0025%时,晶粒分布最为均匀,且6~15μm范围内的晶粒占比60.26%。稀土加入后细化了原奥氏体晶粒,并使组织更为均匀。淬火钢经690℃回火90 min后组织为回火索氏体+回火托氏体的混合组织。随着稀土Ce含量从0增加至0.012%,碳化物析出量减少,稀土的加入抑制了碳化物的析出;碳化物的类型主要为Cr_(23)C_(6)、Cr_(7)C_(3),稀土Ce的加入不改变碳化物的类型;Ce含量为0.012%时,碳化物在晶界处由连续分布转变为断续的团簇分布。

稀土对低碳高铌钢奥氏体晶粒尺寸及Nb、Ti固溶的影响

研究了稀土对低碳高铌钢奥氏体化行为的影响,采用激光共焦显微镜观察了低碳高铌钢的奥氏体原始组织,采用电感耦合等离子体原子发射光谱仪(ICP)测定了不同加热温度下Nb、Ti的固溶量,通过扫描电子显微镜观察未固溶颗粒的大小及分布情况。结果表明,稀土能提高低碳高铌钢原始奥氏体晶粒的均匀性,细化该钢的原始奥氏体晶粒,降低钢中Nb、Ti的固溶温度。加入稀土后,在1250℃加热时奥氏体平均晶粒尺寸由未添加稀土时的36.18μm减小到23.16μm。加热温度为1250℃时,稀土使Nb、Ti的固溶百分含量分别提高了54.1%和44.9%;加热温度为1280℃时,稀土使Nb、Ti的固溶百分含量分别提高了25.6%和13.7%。