合金元素对0Cr17Ni4Cu4Nb不锈钢组织与力学性能的影响—铜（3）

实验室研究了Cu含量对0Cr17Ni4Cu4Nb不锈钢组织与力学性能的影响,通过力学性能测试和金相显微分析,研究结果表明：在淬火冷却速度较快的情况下,随Cu含量的增加,强度增加,塑性下降;随淬火冷却速度的降低,强度下降,且Cu含量越高,强度下降的幅度越大;在淬火缓冷情况下,Cu含量对强度的影响不大;随时效后冷却速度的降低,强度增加;Cu含量控制在中下限容易满足技术条件的要求。     

合金元素-铌对0Cr17Ni4Cu4Nb不锈钢组织与力学性能的影响

实验室研究了Nb含量对0Cr17Ni4Cu4Nb不锈钢组织与力学性能的影响,通过力学性能测试和金相显微分析,研究结果表明：随Nb含量的增加,强度增加,塑性降低;随时效温度的升高,强度下降,上限Nb含量试验料的强度下降较缓;随淬火冷却速度的降低,强度下降;随时效后冷却速度的降低,强度增加;Nb含量控制在中限容易满足技术条件的要求。     

合金元素对0Cr17Ni4Cu4Nb不锈钢组织与力学性能的影响—碳(1)

实验室研究了C含量对0Cr17Ni4Cu4Nb不锈钢组织与力学性能的影响,通过力学性能测试和金相显微分析,研究结果表明:随C含量的增加,As点、Mf点降低,且Mf点可降到室温以下,导致强度降低,塑性、韧性增加;随淬火冷却速度的降低,强度降低,塑性增加;随时效冷却速度的降低,强度增加;选择低的C含量容易满足技术条件要求。     

合金元素对0Cr17Ni4Cu4Nb不锈钢组织与力学性能的影响—铬(2)

实验室研究了Cr含量对0Cr17Ni4Cu4Nb不锈钢组织与力学性能的影响,通过力学性能测试和金相显微分析,研究结果表明:随Cr含量的增加,容易产生δ铁素体,引起C、Cr等元素的偏析,使As点、Mf点降低,且Mf点可降到室温以下,导致强度降低、塑性、韧性增加;随淬火冷却速度的降低,强度降低,塑性增加;随时效冷却速度的降低,强度增加;选择下限的Cr含量容易满足技术条件要求。     

调整处理对0Cr17Ni4Cu4Nb不锈钢组织与力学性能的影响

实验室研究了调整处理工艺对0cr17Ni4Cu4Nb不锈钢组织与力学性能的影响,通过力学性能测试和金相显微组织观察,结果表明：随调整处理温度的提高,强度逐渐增加,塑性、韧性逐渐下降;816℃整处理后,随时效温度的提高,强度逐渐下降,塑性、韧性逐渐增加;在相同的时效温度下,与固溶态相比,调整处理后的强度显著较低但塑性、韧性较高。     

化学成分和热处理工艺对17—4PH钢力学性能的影响

为了解决0Cr17Ni4Cu4Nb在物理性能检验时强度指标比GB／T8732标准值高的问题,研究了化学成分、热处理工艺包括固溶处理、时效处理和冷却速度对0Cr17N-4Cu4Nb的显微组织和力学性能的影响。结果表明：（1）为了提高合格率Cr含量控制下限,M控制在中上限,将δ-铁素体的含量控制在5％以下,化学成分应精确控制减小波动,特别是碳含量;N应分析和控制;（2）在GB8732—88规定的温度范围内（1020℃-1060℃）固溶处理温度对性能的影响不大;（3））冷却速度、试样固溶及第一次时效后进行下一步处理前的温度是获得良好力学性能的关键,并且前者对力学性能的影响程度要大于后者。室温在20℃左右时,冷却速度最合适,合格率最高。     

冷却工艺对X80HD2管线钢组织和性能的影响

试验分析了开冷温度、冷却速度和终冷温度对X80HD2管线钢组织和性能的影响,结果表明,在不同开冷温度下,均能得到铁素体和贝氏体双相组织,随开冷温度的降低,铁素体含量增多,M/A含量增加,屈服强度下降,Rt0.5/Rm下降,均匀伸长率降低;随冷却速度提高,贝氏体组织细化,屈服强度增加,Rt0.5/Rm升高,均匀伸长率降低;随终冷温度降低,M/A细化,抗拉强度降低,Rt0.5/Rm升高,加工硬化速率升高,均匀伸长率升高。最佳冷却工艺参数:开冷温度690℃,冷却速度15℃/s,终冷温度400℃。     

固溶处理对00Cr25Ni7Mo4N双相不锈钢组织和力学性能的影响

研究了真空感应炉(6.5 kg锭)熔炼的00Cr25Ni7Mo4N钢(%:0.007～0.009C、24.50～24.84Cr、6.92～6.99Ni、3.65～3.72Mo、0.27～0.30N)的相比例和固溶处理温度对钢的组织和力学性能的影响。结果表明,随固溶温度由1 050℃增至1 200℃,钢中铁素体含量由48%～50%提高至53%～55%。当固溶温度由1 050℃提高至1100℃,钢的强度下降,伸长率和冲击韧性增加,当固溶温度由1 100℃提高至1 200℃,钢的强度增加,伸长率和韧性降低,该钢最佳固溶温度为1 100℃±50℃。     

热处理制度对选择性激光熔化成形TC4钛合金的组织与力学性能的影响

采用金相显微镜、扫描电子显微镜和电子万能材料试验机研究热处理制度对选择性激光熔化成形技术(SLM)成形TC4(Ti6Al4V)钛合金显微组织和力学性能的影响。结果表明:激光成形样品的组织主要由呈外延生长的粗大柱状晶组成,原始柱状β晶粒的显微组织由大量的针状α′相组成;随退火温度升高,条状α相的宽度先增加后降低,强度降低,塑性增加;在(α+β)两相区固溶时,随固溶温度升高,α相的长宽比增加,α相的间距减小,α束集变大,强度升高,塑性降低;对比该7种热处理制度,800℃保温2 h炉冷为最佳热处理工艺,经该工艺处理的试样综合力学性能较好。     

冷却速度对 900 MPa 级冷轧马氏体钢组织性能的影响

以高氢冷却工艺连退生产线为基础,以 900 MPa 级冷轧马氏体超高强钢为研究对象,研究了连续冷却相变区转变规律和连退快速冷却工艺对钢的力学性能和显微组织的影响。结果表明,连续冷却相变区由先共析铁素体转变区、贝氏体转变区和马氏体转变区组成,随着冷却速度的增加,先共析铁素体含量逐渐下降,贝氏体和马氏体含量逐渐上升,当冷却速度大于 40 ℃/s 时,不再有先共析铁素体生成;当冷却速度大于 80 ℃/s 时,则完全进入马氏体转变区。随着连退快冷工艺中冷却速度的增加,钢的屈服强度、抗拉强度和屈强比逐渐增加,断后伸长率逐渐下降。当冷却速度为 50 ℃/s 时,钢的屈服强度、抗拉强度和断后伸长率就已经达到了 900 MPa 级冷轧马氏体超高强钢的力学性能要求。     

Effect of heat treatment on microstructure and mechanical properties of plastic mold steel 10Ni2Cr2MnCuMoVAl

The effects of solution and aging treatment on microstructure and mechanical properties of 10Ni2Cr2MnCuMoVAl plastic mold steel were experimentally studied. The results show that the dominant microstructure of 10Ni2Cr2MnCuMoVAl steel after solid solution treatment is lath martensite, and higher solution temperature results to larger width of martensite, while the highest value of hardness could be obtained after solution treatment at 890??. After aging, the microstructure consists of lath martensite, granular bainite and carbides. For steel aged at 460-520??, the strength of the material gradually increased with higher aging temperature, while the toughness decreased gradually. When the temperature exceeded 520??, higher temperature led to decreased hardness and increased toughness. Compared the mechanical properties of steel aged at 540?? for different time, the test steel reached the peak of mechanical properties at 8h. By comparing the mechanical properties of the test steels after different aging treatments, the optimized heat treatment process of 10Ni2Cr2MnCuMoVAl steel is solution treatment at 880?? for 2h with air cooling and tempering temperature at 540?? for 4h with air cooling.     

Improvement in Mechanical Properties of Microalloyed Steel 30MSV6 by a Precipitation Hardening Process

 The microstructural evolutions and mechanical properties of vanadium microalloyed steel (30MSV6) during precipitation hardening were studied. The effects of aging temperature and cooling rate on mechanical strength (yield strength and ultimate tensile strength) were similar. Increasing aging temperature or cooling rate firstly increased the mechanical strength of specimens up to their maximum values, which then decreased with further increase in aging temperature or cooling rate. Microstructural evolutions revealed that cooling rate had significant effects on the pearlite interlamellar spacing and size of pre-eutectoid ferrite. Unlike the effect of austenitizing temperature, the pearlite interlamellar spacing and pre-eutectoid ferrite size were decreased by increasing the cooling rate from austenitizing temperature. According to the microstructural evolutions and mechanical properties, the optimal heat treatment process of microalloyed steel 30MSV6 was austenitizing at 950 ℃ for 1 h, air cooling (3. 8 ℃/s) and aging at 600 ℃ for 1. 5 h. This optimal heat treatment process resulted in a good combination of elongation and yield strength.     

0Cr17Ni4Cu4Nb组织及力学性能试验

采取不同热处理方式观察0Cr17Ni4Cu4Nb钢的组织对力学性能的影响。该钢经固溶、时效后,析出与基体保持共格关系的富铜SH（ε—Cu）、NbC、M23C6等碳化物使强度提高,并在480℃时效时,获得最大的强度值。     

Si含量对超超临界汽轮机转子钢30Cr2Ni4MoV组织和性能的影响

30Cr2Ni4MoV钢(%:0.15～0.16C、0.03～0.45Si、0.12～0.14Mn、0.005P、0.005～0.006S、1.62～1.72Cr、3.60～3.63Ni、0.52～0.53Mo、0.07V、≤0.005A1)由10kg真空感应炉冶炼,锻后经930℃空冷+900℃空冷+640℃空冷处理,再经850℃水淬+600℃回火调质处理。试验结果表明,当钢中的Si含量由0.03%增加至0.45%时,钢中马氏体量增加,晶粒更为粗大;钢的抗拉和屈服强度分别从922～936 MPa和868～873 MPa增至1015～1028 MPa和950～959 MPa,但平均冲击功由205 J降至154 J。     

合金元素Ni对Fe-Cu合金析出过程的影响

以添加Ni前后的Fe-Cu合金和Fe-Cu-Ni合金为研究对象,采用金相显微镜(OM)观察了Fe-Cu合金与Fe-Cu-Ni合金时效过程中的显微组织形貌变化,借助硬度测试分析了两种合金在等温时效过程中的硬度变化规律,并利用透射电子显微技术(TEM)进行了两种合金的析出相精细结构观察与衍射分析,在此基础上,通过实验与理论分析相结合的方法,探索了Ni元素的添加对含铜钢的显微组织、硬度及析出相形貌、尺寸的影响。显微形貌及硬度测试显示,Ni元素的加入提高了钢的淬透性,从而促进了淬火马氏体的形成,合金的强化效果显著增强,硬度与不添加Ni元素的实验钢相比有明显提高;析出相观察发现,含铜钢中Ni元素的加入加快了形核的进程,提高了析出相颗粒的形核的速率,促进富Cu相的析出,从而细化了析出相的尺寸;透射电子衍射分析表明,Cu在时效过程中会发生结构演化,逐渐形成了bcc结构的富Cu亚稳相。     

Influence of heat treatment conditions on the mechanical properties of Ti–6Al–4V alloy

In the current work, several heat treatments were carried out below and above the beta-transition temperature of the Ti–6Al–4V alloy followed by aging at 550 °C for 6 hours. The resultant microstructures and their effects on the mechanical properties of Ti–6Al–4V alloy were investigated. The results showed that solution treatment of Ti–6Al–4V samples followed by water quenching from β and α/β fields raised the alloy hardness from 380 to 575 and 656?HV, respectively, while no remarkable changes were observed after aging. The hot tensile strength of the as-forged sample increased from 671 to 756?MPa after water quenching from the ß- or α/ß- field, while the air cooling from β-phase field decreased the tensile strength to 644 MPa. The fracture mode of the tensile samples was more ductile in case of the solution-treated samples compared to the as-forged samples. A subsurface layer was formed due to the diffusion of oxygen into the surface at high temperatures. This layer which is known as ‘oxygen diffusion layer’ masked the differences of wear behaviour of the specimens.