配分工艺对中碳Ti-Mo高强Q&P钢组织和性能的影响

摘要：采用盐浴实验、扫描电镜、透射电镜、拉伸实验和磨损实验等手段，研究了配分工艺对中碳Ti Mo钢组织和性能的影响，分析了不同配分工艺处理下的组织演变和性能变化。结果表明，显微组织主要由回火马氏体、渗碳体、(Ti，Mo)C粒子组成。随着配分时间的延长和配分温度的升高，板条马氏体数量减少，马氏体板条厚度增加，边界钝化。此外，随着配分温度从310℃提高至400℃，抗拉强度、硬度和低温冲击韧性同时下降，分别降低约250MPa、56HV和15J。最后，Ms以下温度配分（310℃）试样的耐磨损性能明显优于Ms以上温度配分（400℃）试样。Ms以下温度配分试样磨损表面形貌以塑性变形为主，Ms以上温度配分试样磨损表面以犁沟为主。     

含钛中锰钢淬火-配分组织及力学性能

为了研究淬火配分含钛中锰钢的组织与力学性能,借助扫描电子显微镜,透射电子显微镜、电子背散射衍射技术与万能拉伸试验机、磨粒磨损试验机等,分析与测试了含钛中锰钢在165～240℃淬火380℃配分处理后组织、强度、塑性与磨粒磨损性能.结果 表明,试验钢淬火-配分组织主要为板条状一次马氏体、块状二次马氏体及残余奥氏体,同时含有...     

Ms以下温度等温淬火对中碳贝氏体钢相变和性能影响

摘要：设计了马氏体起始相变温度（Ms）以上和以下2个不同温度等温淬火试验，结合热膨胀仪、扫描电镜显微组织、X光衍射和拉伸试验等试验手段，研究了对比于Ms以上温度等温淬火试验，Ms以下等温淬火对中碳贝氏体钢相变、组织和性能的影响。结果表明，贝氏体相变可以发生在Ms温度以下，且其相变动力学被明显促进。相比于Ms以上温度等温淬火，Ms温度以下等温淬火虽然可以加速相变动力学，但导致强度和伸长率下降，因此降低了最终的力学性能。这主要是因为Ms温度以下等温淬火试样组织内部出现了大量的回火无热马氏体（AM）和少量的贝氏体和残余奥氏体（RA）。因此，Ms温度以下等温淬火热处理后的组织性能未必优于Ms温度以上等温处理后组织性能，这主要取决于具体的成分和工艺。     

Effect of quenching temperature on the microstructure of Si-containing steel during quenching and partitioning

This study aims to investigate the effect of the 1-step quenching and partitioning( QP) process on the microstructure and the resulting Vicker's hardness of 0. 3C-1. 5Si-1. 5M n steel by using in-situ dilatometry,optical microscopy( OM),scanning electron microscopy( SEM),X-ray diffractometry( XRD),and Vicker 's hardness measurement. Systematic analyses indicate that the microstructure of the specimens quenched and partitioned at150 ℃,200 ℃,250 ℃,and 300 ℃ mainly comprises lath martensite and retained austenite. The dilatometry curve of the specimen partitioned at 150 ℃ is presumably ascribed to the formation of isothermal martensite. In the early stages of partitioning at 200 ℃,the nearly unchanged dilatation curve is closely related to the synergistic effect of isothermal martensite formation and transitional epsilon carbide precipitation. In the later stages of partitioning at200 ℃,the slight increase in the dilatation curve is due to the continuous isothermal martensite formation. With further increase in partitioning temperature to 250 ℃,the dilatation increases gradually up to 3600 s,which is related to carbon partitioning and lower bainite formation. Partitioning at a higher temperature of 300 ℃ causes a rapid increase in the dilatation curve during the initial stages,which subsequently levels off upon prolonging the partitioning time. This is mainly attributed to the rapid diffusion of carbon from athermal martensite to retained austenite and continuous formation of lower bainite.     

基于镀锌的Q/P工艺对钢组织与性能的影响

基于热镀锌的工艺特点制定Q/P热处理工艺,研究了奥氏体化温度及配分时间对组织和性能的影响。结果表明,随奥氏体化温度从800升至900℃,Q/P处理后组织中铁素体量减少,马氏体和残余奥氏体量增加,钢的屈服强度、抗拉强度均升高,伸长率降低,900℃奥氏体化时钢的强塑积最高。在460℃配分10、30、60s时,随着配分时间延长,组织中马氏体发生回火且发生大量贝氏体转变,造成Q/P处理后残余奥氏体量减少,使钢的抗拉强度、伸长率和强塑积均下降。     

回火温度对Cu-Cr-Ti马氏体耐磨钢组织及强韧性的影响

摘要：矿山机械用耐磨钢构件服役环境恶劣而常常出现磨损失效,研究适用于复杂工况下的高耐磨钢成分、工艺与组织性能的关系,有利于提高耐磨构件的服役寿命并降低经济损失。利用SEM、TEM、洛氏硬度计、万能拉伸试验机及冲击试验机等,研究了160～400℃不同回火温度下Cu-Cr-Ti马氏体耐磨钢的组织形貌、强度硬度及-20℃冲击韧性的变化。结果表明,试验钢淬火态组织主要为板条马氏体,当回火温度为160℃时,马氏体板条依然清晰,但随回火温度升高到400℃,马氏体板条界渐渐消失,基体中出现大量片状或粒状渗碳体。EDS分析发现样品钢基体中含有纳米级Ti、Nb的碳氮化物。随回火温度升高,基体组织演变导致强化机制发生变化,回火温度为300℃,综合力学性能最佳,其抗拉强度为1500MPa,屈服强度1100MPa,伸长率为15.5%。随回火温度升高,-20℃冲击韧性由60J/cm2逐渐降低到36.3J/cm2。     

回火温度对Ti-V-Mo复合微合金钢组织及硬度的影响

摘要：利用OM、SEM、TEM、EBSD和维氏硬度计等手段研究了回火温度对Ti-V-Mo复合微合金钢组织转变及硬度的影响，探讨了 (Ti,V,Mo)C在不同回火温度下的析出规律及其对硬度的作用机制。结果表明，在450～600℃回火时，随着回火温度的升高，硬度呈直线上升趋势，在600℃回火时硬度具有最大值450HV。随着回火温度的升高，试验钢马氏体板条块宽度由7.3μm增大至9.9μm，600℃回火时析出相粒子的平均尺寸为5nm，10nm以下的(Ti,V,Mo)C粒子可高达90%，理论计算沉淀强化增量导致硬度上升90.7HV，远高于基体软化造成的硬度损失，因而析出强化是影响Ti-V-Mo复合微合金钢硬度的主要因素。在600～650℃回火，大小角度晶界分布比例基本相同，马氏体板条块的平均尺寸变化不大，但是析出相的平均尺寸由5nm提高到5.6nm，尺寸小于5nm的(Ti,V,Mo)C粒子所占比例逐渐下降，导致硬度下降。     

淬火-贝氏体区配分工艺及钢的组织性能

 Q&P（Quenching and Partitioning, 淬火配分）工艺在CCE条件下,通过采用[Ms]和[Mf]点之间的最佳淬火温度和低于[Ms]点的配分温度,避免配分阶段的贝氏体形成最终可以得到最高含量的残余奥氏体组织。但试验中得到不足体积分数8%的残余奥氏体含量限制了钢塑性的提高。通过提出淬火-贝氏体区配分工艺,并应用在(0.21～0.29)C-(1.5~2.0)Si-(1.5～2.1)Mn成分钢,得到了体积分数12%左右的残余奥氏体含量和25%左右的伸长率,同时强度保持在1 000～1 100 MPa,强塑积最高达到36.6 GPa·%。不同的淬火温度和配分温度试验结果表明,工艺变化对强度影响较低,伸长率和强塑积随着配分温度的提高而提高,其中270 ℃的淬火温度试样的提高幅度高于245 ℃淬火试样,采用Q&PB工艺得到了无碳贝氏体＋马氏体＋残余奥氏体的三相组织。淬火和贝氏体区配分得到了优异的强度和塑性的结合,为新一代汽车用钢的发展提供新的思路。     

回火温度对30Cr15Mo1N微观组织和力学性能影响

 为探索高氮马氏体钢在回火过程中组织性能演变，对30Cr15Mo1N高氮钢进行了不同温度下的回火处理，利用OM、XRD、拉伸、冲击、SEM和TEM等方法研究了高氮钢在回火过程中微观组织和力学性能的变化规律。结果表明，30Cr15Mo1N钢经淬火和低温处理后在150～700 ℃回火，随回火温度升高，显微组织中马氏体基体逐渐发生回复与再结晶，组织中马氏体形态逐渐消失，碳氮化物先在马氏体板条边界呈片状或棒状析出，逐渐演变为颗粒状弥散分布，700 ℃时碳氮化物聚集长大、球化。随着回火温度升高，30Cr15Mo1N钢的基体持续软化，析出强化不断增强，导致其在500 ℃以下回火时强度变化较小，抗拉强度保持在2 000 MPa以上；当回火温度大于500 ℃时，强度随回火温度升高而线性下降。随着回火温度升高，30Cr15Mo1N钢的U型缺口冲击吸收功先基本保持不变再持续升高，在700 ℃回火后冲击韧性达到45 J/cm2。不同回火温度下冲击性能的变化与其强度、塑性变化密切相关，冲击韧性好坏主要由塑性大小决定。     

Selection of Heat Treatment Process and Wear Mechanism of High Wear Resistant Cast Hot-Forging Die Steel

 Dry sliding wear tests of a Cr-Mo-V cast hot-forging die steel was carried out within a load range of 50-300 N at 400 ℃ by a pin-on-disc high-temperature wear machine. The effect of heat treatment process on wear resistance was systematically studied in order to select heat treatment processes of the steel with high wear resistance. The morphology, structure and composition were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS); wear mechanism was also discussed. Tribo-oxide layer was found to form on worn surfaces to reduce wear under low loads, but appear inside the matrix to increase wear under high loads. The tribo-oxides were mainly consisted of Fe3O4 and Fe2O3, FeO only appeared under a high load. Oxidative mild wear, transition of mild-severe wear in oxidative wear and extrusive wear took turns to operate with increasing the load. The wear resistance strongly depended on the selection of heat treatment processes or microstructures. It was found that bainite presented a better wear resistance than martensite plus bainite duplex structure, martensite structure was of the poorest wear resistance. The wear resistance increased with increasing austenizing temperature in the range of 920 to 1120 ℃, then decreased at up to 1220 ℃. As for tempering temperature and microstructure, the wear resistance increased in following order: 700 ℃ (tempered sorbite), 200 ℃ (tempered martensite), 440 to 650 ℃ (tempered troostite). An appropriate combination of hardness, toughness, microstructural thermal stability was required for a good wear resistance in high-temperature wear. The optimized heat treatment process was suggested for the cast hot-forging steel to be austenized at 1020 to 1120 ℃, quenched in oil, then tempered at 440 to 650 ℃ for 2 h.     

Effects of combined high and low temperature deformation processing of β III titanium

The structure and properties of β III titanium alloy (nominal composition: 11.5 pct Mo, 6 pct Zr, 4.5 pct Sn, bal Ti) were studied as a function of combined high and low temperature ther-momechanical processing. A water quenched extrusion was deformed various amounts by swaging at room temperature prior to the aging treatment. No re-solution heat treatment was employed. The swaging introduced mechanical twinning and a small amount of stress induced orthorhombic martensite. Following a 900°F, 8 hr aging treatment, substantial increases in yield and tensile strength were observed, combined with a severe decrease in tensile ductility in samples with small amounts of swaging. The orientation and morphology of the deformation products have a critical influence on tensile ductility. A decrease in the plane strain fracture toughness accompanied the large increase in tensile strength.     

新型耐高温磨损钢板组织性能与高温磨损行为研究

随着低合金耐磨钢应用领域逐渐增加,对其中高温条件下的耐磨性能提出了要求.通过成分设计、控制轧制和离线热处理工艺制备了一种Mo、V合金化新型低合金高温耐磨钢.初步探索了其在300～500℃温度范围的高温磨损行为和组织演变,并与同硬度级别的商用常规耐磨钢NM450进行了对比分析.结果 表明:通过添加Mo和V等元素可以抑制位...     

Influence of Heat Treatment Temperature on Micro-structure and Property of 00Cr13Ni5Mo2 Su-permartensitic Stainless Steel

The microstructural evolution and mechanical property of 00Cr13Ni5Mo2supermartensitic stainless steel(SMSS)subjected to different heat treatments were investigated.Room tensile tests,hardness tests,scanning electron microscopy,transmission electron microscopy and X-ray diffraction were conducted on the heat-treated steels.It is found that the microstructure of the heat-treated steel is composed of tempered lath martensite,retained austenite andδ-ferrite.The austenitizing temperature and tempering temperature have a significant effect on the microstructural changes,which leads to the complex variations of mechanical properties.The fine tempered lath martensite and more dispersed reversed austenite in the microstructure facilitate improving the comprehensive mechanical properties of the studied steel.The optimal heat treatment process of 00Cr13Ni5Mo2SMSS is obtained by austenitizing at 1 000℃for 0.5h+air cooling followed by tempering at 630℃for 2h+air cooling,where the excellent combination of tensile strength,elongation and hardness can be achieved.     

22SiMn2TiB钢淬火与回火过程中的组织演变

以超高强度钢 22SiMn2TiB 为对象,研究了在淬火、回火和配分状态下组织的演变规律.采用光学金相显微镜(OM)、扫描电镜(SEM)和 X 射线衍射技术(XRD)研究了不同处理状态下组织的演变规律.实验表明,回火或配分温度低于 320 ℃,板条马氏体组织形貌没有明显变化,且不随回火和配分时间的变化而变化;在此温度以上进行配分,不论配分时间的长短,组织皆转变为回火组织.表明 320 ℃为该钢材的临界回火、配分温度.随着回火温度的升高,位错密度下降;且 320 ℃以下温度回火或配分,马氏体衍射峰的半峰宽 FWHM 只是略有减少,表明虽然板条马氏体的组织形貌没有明显变化,但板条内的位错密度和内应力降低.     

谐波减速器柔轮用特殊钢RL40的组织特性

通过光学显微定量分析和热膨胀实验,研究了柔轮用钢RL40(/％:0.40C,0.90Cr,1.85Ni,0.25Mo,0.05Nb,0.016Ti)的微观组织、相变点和奥氏体晶粒粗化规律等材料基本特性.结果表明:轧材组织为贝氏体+马氏体,原始奥氏体晶粒平均尺寸为14.0 μm,晶粒度级别为9.0～9.5,平均标准偏差均...     

淬火温度对马氏体/铁素体双相钢组织性能的影响

双相钢具有优异的力学性能,而马氏体/铁素体的含量对其性能具有重要影响。通过实验调节淬火温度制备了不同马氏体体积分数的双相钢,采用金相显微镜对马氏体/铁素体组织形貌及分布进行了定性观察;其次利用电子背散射衍射技术(EBSD)并结合高斯拟合,发现马氏体/铁素体衍射花样衬度呈双峰分布,据此对钢中马氏体体积分数进行了定量统计。结果表明:淬火温度为730℃时,马氏体体积分数仅为19.09%。随淬火温度增加,双相钢中马氏体含量提高;于790℃淬火时,马氏体体积分数达到30.96%,提高了62%。此外,对试验双相钢力学性能进行对比分析发现:随淬火温度升高,双相钢的抗拉强度明显提高,屈服强度也呈上升趋势,这主要与马氏体含量增加有关;而双相钢延伸率显著降低,这主要是由于铁素体含量减少,且形貌由利于变形的针状转变为多边形所致。     

压铸模具钢4Cr5Mo2V的组织和碳化物的高温行为

摘要：通过测定4Cr5Mo2V钢在不同冷却速度下的相变膨胀曲线,得到其过冷奥氏体连续冷却转变曲线（CCT曲线）及Ac1、Ac3和Ms点温度。结合各相变点和Thermal-Calc分析结果,利用原位观察研究了4Cr5Mo2V钢在升温、保温和降温过程中的组织和及升温过程中碳化物的变化规律。结果表明,4Cr5Mo2V钢的相变点温度分别是：Ac1为820℃,Ac3为855℃,Ms为275℃;升温过程中,Cr23C6先于VC溶解,并在表面产生浮凸和空洞;保温过程中,晶粒长大机制为旧晶界迁移,并使得晶粒发生吞并和长大;连续冷却过程中,4Cr5Mo2V钢马氏体形的生成是以先形成的板条为基准逐步形成彼此平行的板条而构成板条束,或者是先形成的板条可以触发产生另一方向（60°或120°）的板条马氏体,构成多边形等具有几何形状的组织特征。     

深冷处理对NM500耐磨钢性能与磨损行为的影响

以一种自行设计的NM500级别耐磨钢为研究对象,利用冲击磨损试验,分析了深冷处理对其组织性能和磨损行为的影响。结果表明,NM500耐磨钢经深冷处理后,抗拉强度、硬度和冲击韧性均有提高,在淬火+深冷+回火处理后,最佳的综合力学性能可达抗拉强度1 910 MPa、硬度523HB、冲击韧性24.3 J/cm2,此时试验钢组织主要为马氏体,有Nb和Ti的碳化物析出。深冷处理通过残余奥氏体向马氏体转变,减少了不稳定相的含量,提升了试验钢的力学性能,从而使淬火+深冷+回火处理后的试验钢具有更高的耐磨性,此时的磨损机制以磨粒磨损为主,磨损形貌主要为犁沟、犁皱。而未经深冷处理的淬火+回火处理试验钢磨损机制以黏着磨损为主,磨损形貌主要为剥落坑和切削。     

SPS制备WC颗粒增强高合金工具钢的组织及力学性能

采用放电等离子烧结技术(SPS)制备不同WC颗粒含量的HGSF01高合金工具钢.通过扫描电镜、X射线衍射技术等测试手段研究烧结态的组织、物相组成和力学性能,并对试样的弯曲断裂断口进行分析.实验结果表明:随着烧结温度的提高,材料密度不断提高;随着增强颗粒含量的增加,材料的硬度和抗弯性能得到明显提升,但致密度有所下降;烧结态试样的主相是马氏体,同时还伴有残余奥氏体、Cr7C3、VC、Cr2VC2及少量的Mo、Cr碳化物;由弯曲试验的断口分析得知,1 050℃烧结试样的断口形貌特征为多种断裂机制并存.     

固溶温度对新型无钻马氏体时效钢00Nil4Cr3Mo3Ti 冲击性能的影响

研究了固溶温度750～1050℃对00Ni14Cr3Mo3Ti新型马氏体时效钢冲击性能和硬度的影响,并用扫描电镜观察试验钢冲击断口的形貌和固溶态显微组织。试验结果表明,钢的固溶温度低于900℃时,随着固溶温度的升高,基体中未溶的Laves相逐渐溶解,固溶态和510℃ 5 h时效态的冲击性能均随着固溶温度的上升而提高;固溶温度高于900℃,固溶态冲击性能随着固溶温度的上升而提高,该钢固溶态冲击功由900℃的215J增加至1050℃固溶的226J,但时效态冲击性能随着固溶温度上升而降低,510 5h时效钢的冲击功由900℃最大值62J降至1050℃固溶的25J。