热处理工艺对Cr12MoV钢组织及硬度的影响

采用金相显微镜、XRD射线衍射仪及维氏硬度计等,研究了普通热处理和深冷处理工艺对Cr12MoV钢显微组织及硬度的影响.结果 表明:Cr12MoV钢经普通热处理和深冷处理淬火后的组织均为隐针马氏体+残余奥氏体+碳化物,200℃低温回火后组织转变为回火马氏体+碳化物+残余奥氏体.深冷处理可大幅减少钢中残余奥氏体,提升钢的硬...     

深冷处理对AHPT15M粉末高速钢回火转变的影响

对退火态AHP T15M粉末高速钢进行盐浴淬火处理,然后对退火态样品与淬火态样品进行深冷处理、回火处理和同步热磁分析,研究深冷处理对AHP T15M粉末高速钢回火转变的影响。结果表明,退火态粉末高速钢中的铁素体含量(体积分数)约为71.5%;淬火态钢中的马氏体含量(体积分数,下同)约为45.2%,在经过1、2、3次823 K/1 h连续回火处理后,马氏体含量分别约为68.5%、71.0%和71.3%;回火前增加143 K深冷处理工序,在深冷后和1、2、3次回火后,钢中马氏体含量分别约为59.8%、69.9%、70.9%和71.3%。深冷处理可提前残留奥氏体向马氏体的转变进程、抑制残留奥氏体中的碳化物析出,并促进马氏体中更大量(约2.3%)的微细碳化物析出,使钢的硬度提高52 HV0.1。     

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。     

深冷处理后W18Cr4V高速钢的显微组织

 用X射线衍射和透射电子显微镜研究了W18Cr4V高速钢循环深冷处理前后的显微组织。结果表明,与一次长时间深冷处理相比,多次循环深冷处理后马氏体轴比和碳含量明显下降,奥氏体含量进一步减少,有大量新的超细弥散碳化物颗粒沿马氏体孪晶带和位错线析出,表明高速钢多次循环深冷处理效果好于一次长时间深冷处理。     

冷冲模钢的深冷处理

本文研究了深冷处理对Cr_(12)钢组织、结构和性能的影响。金相和X射线研究表明,深冷处理(-196℃)不仅使残余奥氏体大大减少,而且使马氏体在一定程度上分解,从中析出大量的细小碳化物。机械性能试验表明,深冷处理使Cr_(12)钢硬度提高,而且分布均匀,改善了材料的耐磨性。深冷处理后材料的冲击韧性和断裂韧性下降很少。深冷处理可显著地提高冷冲模的使用寿命。     

深冷处理对H13钢组织结构和热稳定性的影响

 为了研究深冷处理对H13热作模具钢热稳定性的影响及组织演化规律,利用洛氏硬度计、X射线衍射仪、扫描电子显微镜及透射电子显微镜等对经不同热处理工艺处理后H13热作模具钢的热稳定性及显微组织进行了表征。结果表明,深冷处理促使部分残余奥氏体转变为马氏体,导致深冷处理后试验钢的硬度高于淬火态试验钢的硬度。经深冷处理后试验钢在540 ℃回火20 h过程中其硬度均比常规热处理的试验钢硬度高,深冷处理的试验钢具有更好的热稳定性。与常规热处理的试验钢相比,深冷处理促使钢中碳原子偏聚并在回火过程中以碳化物的形式析出,导致深冷处理的试验钢回火后马氏体基体中碳的质量分数降低。透射电镜结果显示,试验钢在回火过程中析出的大量弥散分布的纳米级M₂₃C₆型碳化物,经长时间回火后碳化物粗化致使试验钢硬度随着回火时间的增加而下降。     

卷取机助卷辊表面堆焊研制

采用埋弧堆焊工艺在20CrNiMo表面堆焊6-8mm的Cr13系列新型马氏体不锈钢熔覆材料，分析熔覆金属的组织形貌，并进行耐磨性和硬度测定。研究结果表明，熔覆金属的焊态组织主要为板条状马氏体和大量的残余奥氏体，并伴有少量的回火马氏体，同时在马氏体间可见少量较小的碳化物。经500℃回火后其组织为回火马氏体和少量残余奥氏体，碳化物析出相增多。焊态硬度值为46-50HRC,回火后硬度值为54-58HRC,磨损失重是45#淬火钢的0.31倍。经过六个月的使用后，助卷辊的单边磨损量1.13mm,辊面平均硬度值在54.2HRC,说明该熔覆金属具有优异的耐磨性能。     

深冷处理对18Ni马氏体时效钢性能及组织的影响

通过采用固溶、深冷及时效等处理方式,对18Ni马氏体时效钢进行了不同热处理工艺试验,研究了深冷处理对18Ni马氏体时效钢性能及组织的影响.结果表明,18Ni马氏体时效钢经深冷处理后硬度能有效提高;随着深冷处理时间的延长,材料的性能仍有所提升.深冷处理能使材料中的残余奥氏体向马氏体转变,但不能完全消除残余奥氏体.     

0.1C-5Mn钢两相区退火后的残余奥氏体与力学性能

通过ART(奥氏体逆相变)热处理工艺,研究了两相区退火温度对0.1C-5Mn钢中残余奥氏体与力学性能的影响。采用SEM、XRD、室温拉伸等分析测试手段,表征了试验钢组织形貌、亚稳奥氏体含量以及力学性能。结果表明,试验钢经ART工艺处理后,室温组织主要由铁素体与残余奥氏体组成;随退火温度升高,试验钢中出现碳化物析出与再溶解,同时板条状形变马氏体回复多边化形成等轴铁素体,颗粒状奥氏体过冷转变为板条状和块状马氏体;630、645、660℃退火1h试样中奥氏体体积分数相近,分别为18.4%、19.5%、18.8%,随温度升高,奥氏体含量骤降,大量逆相变奥氏体转变为马氏体;综合不同退火温度,表明试验钢经660℃退火可获得最佳的综合力学性能。     

14Cr 1Mo 15V高铬白口铸铁的深冷硬化机理

 采用X射线衍射、磁性法和硬度测量等方法研究了深冷处理对高铬白口铸铁显微组织和硬化行为的影响。结果表明，去稳+深冷处理铸铁的硬度比未深冷处理铸铁明显提高，从HRC 641提高到HRC 670。这是因为深冷处理使高铬白口铸铁的残余奥氏体量大大下降，马氏体的大量形成和细微二次碳化物的析出强化作用显著提高了高铬白口铸铁的硬度。深冷处理后铸铁组织中仍存在少量残余奥氏体。     

合金元素对高氮不锈轴承钢组织与性能的影响

采用金相、扫描、X射线衍射和电化学等方法研究了合金元素对高氮不锈轴承钢组织性能的影响.结果表明:钢中加氮细化组织与碳化物,析出相尺寸随着氮含量的增加而降低.高氮不锈轴承钢1030、1050℃淬火后残余奥氏体体积分数达到20％～35％,而且碳氮含量越高,残余奥氏体越多.经冷处理及回火后残余奥氏体体积分数降至7％～10.3...     

高氮不锈轴承钢的微观组织与性能研究

利用OM、SEM、XRD和电化学方法对X60N高氮不锈轴承钢(/％:0.63C,15.00Cr,0.61Mo,0.190N)进行组织观察、室温和高温力学性能及耐蚀性能研究.结果表明,钢中降碳加氮可显著降低粗大共晶碳化物的数量及尺寸,X60N钢加氮后的原始奥氏体晶粒尺寸及碳化物明显细化.X60N钢经1050 ℃奥氏体化淬...     

Comparison of microstructure and property of high chromium bearing steel with and without nitrogen addition

Microstructure and property of bearing steel with and without nitrogen addition were investigated by microstructural observation and hardness measurement after different heat treatment processing. Based on the microstructural observation of both 9Cr18 steel and X90N steel,it was found that nitrogen addition could effectively reduce the amount and size of coarse carbides and also refine the original austenite grain size. Due to addition of nitrogen,more austenite phase was found in X90N steel than in 9Cr18 steel. The retained austenite of X90N steel after quenching at 1 050 °C could be reduced from about 60% to about 7% by cold treatment at-73 °C and subsequent tempering,and thus finally increased the hardness up to 60 HRC after low temperature tempering and to 63 HRC after high temperature tempering. Furthermore,both the wear and corrosion resistance of X90N steel were found much more superior than those of 9Cr18 steel,which was attributed to the addition of nitrogen. It was proposed at last that nitrogen alloying into the high chromium bearing steel was a promising way not only to refine the size of both carbides and austenite,but also to achieve high hardness,high wear property and improved corrosion resistance of the stainless bearing steel.     

热处理工艺对Cr12MoV钢组织、硬度及耐磨性的影响

本试验研究了不同淬火和回火工艺热处理对Cr12MoV钢组织、硬度和磨损性能的影响。实验结果表明:当在1050~1100℃范围内淬火、520℃回火时,得隐针马氏体+少量残余奥氏体组织,材料硬度与耐磨性均较好;当在1100℃淬火,各温度二次回火硬度均较一次回火高,当在550℃回火时,试验钢实现二次硬化,且残余奥氏体大量转变,硬度和耐磨性达最大值,材料性能最优。     

中高碳贝氏体钢的组织和耐磨性

对一种新型中高碳贝氏体钢的组织，转为动力学和耐磨性进行了研究，中高碳贝氏体钢空冷后的组织为贝氏体，马氏体，碳化物和残留奥氏体，组织细小均匀，大截面实物硬度测定和组织观察表明，截面上具有高硬度，并组织分布均匀，中高碳贝氏体钢具有高的耐磨性。     

Study of Wear Stabilisation in Cryoprocessed Cobalt-Based High Speed Steel

Cryogenic treatment is employed for high speed tool steels in order to enhance their wear resistance. The improvement in wear resistance is associated with a decrease in retained austenite and or by formation of eta-carbide/nano-scale carbides. In the present work, a complex alloyed high speed tool steel (M35) specimens were hardened at 1,200?°C, triple tempered at 400?°C, cryosoaked at ?185?°C for 4?C48?h and soft tempered (100?°C). The microstructure of the samples were characterised for hardness, carbide density, impact energy, wear loss and residual stress. Influence of these measured parameters on wear behaviour was studied to understand underlying wear mechanism. The cryotreated specimens exhibited mild to stable wear transition at 16?h and then subsequent wear stabilisation for all higher cryosoaking intervals.     

Effect of Cryogenic Treatment on Property of 14Cr2Mn2V High Chromium Cast Iron Subjected to Subcritical Treatment

Effect of cryogenic treatment on the microstructure, hardening behavior and abrasion resistance of 14Cr2Mn2V high chromium cast iron （HCCI） subjected to subcritical treatment was investigated. The results show that cryogenic treatment after subcritical treatment can obviously improve the hardness and abrasion resistance of HCCI because abundant retained austenite is transformed into martensite and fine secondary carbides E（Fe, Cr）23 C6 ] precipitate. The amount of martensite and precipitated secondary carbide in HCCI experiencing subcritical treatment followed by cryogenic treatment was more than that experiencing the subcritical treatment followed by air cooling. When the abrasion resistance of HCCI reaches the maximum, its microstructure contains about 15 % retained austenite. Cryogenic treatment can further reduce the austenite content but the retained austenite cannot be transformed in to martensite completely.     

调质热处理对55NiCrMoV7模具钢组织与力学性能的影响

采用扫描电镜(SEM)、硬度测试、Ⅴ型冲击实验和单向拉伸实验结合有限元建模仿真,研究了55NiCrMoV7模具钢在不同淬火温度(790～910℃)、回火温度(100～650℃)下的微观组织演化和力学性能的变化规律.结果表明,随着淬火温度升高,球状碳化物逐渐溶解到马氏体基体中,马氏体组织不断长大、粗化,残余奥氏体逐渐增多...     

Microstructure and Wear Resistance in Medium and High C Steels Treated by Quenching and Partitioning

The quenching and partitioning (Q&P) steels have shown to be promising candidates to be applied in fields where wear resistance is required. In this study, a medium and a high C steel are heat treated by Q&P and the resulting microstructure, hardness, and wear resistance are characterized. The mechanical stability of the austenite phase under wear test conditions is investigated. It is found that the stability of austenite is very high in the high C steel and decreases in the medium C steel. Additionally, the hardness and wear behavior of the Q&P-treated steels are compared with the results obtained for quenching and tempering (Q&T) treated samples, showing that, although the hardness of Q&P steels is quite lower, the obtained wear rates are similar. It means that in the studied Q&P steels, although the austenite transformation into martensite does not occur considerably, the presence of austenite might play a key role in the wear resistance.