热等静压对ZL205A壳体铸件缺陷及力学性能的影响北大核心CSCD

研究了热等静压(520℃±10℃,120 MPa,2 h)对ZL205A合金壳体铸件缺陷、组织及力学性能的影响。结果表明:铸件缩松缺陷等级为4级,热等静压后经X光检测未见缺陷;T5处理后,铸件本体抗拉强度由428 MPa提高到477 MPa,伸长率由2.3%提高到6.8%;热等静压后铸件晶粒度无变化。     

热等静压对ZL205A壳体铸件缺陷及力学性能的影响

研究了热等静压(520℃±10℃,120 MPa,2 h)对ZL205A合金壳体铸件缺陷、组织及力学性能的影响。结果表明:铸件缩松缺陷等级为4级,热等静压后经X光检测未见缺陷;T5处理后,铸件本体抗拉强度由428 MPa提高到477 MPa,伸长率由2.3%提高到6.8%;热等静压后铸件晶粒度无变化。     

热等静压制备Si_p/Al-Cu复合材料的组织与性能

采用热等静压(HIP)技术制备50Sip/Al-Cu和70Sip/Al-Cu复合材料(50Sip/Al-4.0Cu和70Sip/Al-4.0Cu,Si含量为体积分数,Cu的质量分数为4.0%),利用XRD和扫描电镜研究热等静压态样品的相组成和组织形貌,并测试其主要物理和力学性能。结果表明:材料完全致密、Si颗粒在Al基体中分布均匀且组织细小;热等静压态的50Sip/Al-Cu和70Sip/Al-Cu复合材料的热膨胀系数分别为12.7×10 6和8.7×10 6K 1,抗弯强度分别为395和350MPa,热处理后的材料强度拉弯可进一步提高至548和397 MPa,与采用其他技术制备的同类材料相比,热等静压制备的Sip/Al-Cu复合材料在保持低膨胀系数的同时具有更高的抗弯强度及其他力学性能。     

热等静压处理对Ti6242合金铸件的组织和拉伸性能的影响

研究Ti6242合金铸件及经热等静压后的组织和拉伸性能变化,观察分析了熔炼铸坯和重力铸造铸件热等静压处理前后的组织,并测试了其拉伸性能。结果表明,热等静压消除了铸造时产生的缩松、缩孔等缺陷,增加了材料的抗拉强度。经热等静压处理后Ti6242合金铸件的抗拉强度(sm)为852 MPa,较熔炼铸坯的提升了9.2%,较重力铸造铸件的提升了3.3%。热等静压处理后Ti6242合金铸件的伸长率为6.32%,较熔炼铸坯的提升了13%,而较重力铸造铸件的降低了8.9%。     

热等静压扩散焊制备耐磨层的组织与性能

采用热等静压粉-固连接工艺,研究了0Cr18Ni1oTi合金与Stellite6钴基粉末经热等静压扩散连接及热处理后,耐磨层的组织、力学性能及界面区元素扩散情况.结果表明,热等静压制备的耐磨层组织均匀,主要由Co、Cr3C2、Cr23C6和CrSi2等相组成;界面处W、Fe、Co、Ni和Cr等元素相互扩散,扩散区宽度为40 μm,形成了良好的冶金结合,其结合强度约为500 MPa;耐磨层硬度达到55 HRC以上.钴基耐磨层具有良好的耐磨性,热处理后,耐磨层材料的硬度及强度有所提高,XRD分析显示有CoWSi、CrSi2和C06 W6C相析出有利于提高材料的硬度.     

TC4与93W合金热等静压扩散连接技术研究

以KOVAR合金作为中间过渡层材料,应用扩散连接技术,在热等静压机内对W-Fe-Ni合金与Ti-6Al-4V合金进行扩散连接。采用SEM对连接界面的元素分布进行了分析,并测试了连接件的抗拉强度。结果表明,采用140 MPa,980℃,30 min热等静压工艺、KOVAR合金为过渡层材料,可实现W-Fe-Ni合金与Ti-6Al-4V合金冶金结合,抗拉强度为190 MPa。     

热等静压对铸造AlSi7Cu2Mg合金缺陷及性能的影响

采用砂型铸造AlSi7Cu2Mg铝合金阶梯形铸件,对不同部位试样进行等静处理,研究了不同热等静压压力(80~120 MPa)、时间(1~3h)对不同壁厚铸件缺陷及性能的影响。结果表明,随着热等静压压力增大和保压时间延长,不同壁厚铸件孔洞减少、密度提升,抗拉强度相应增大。铸件壁厚越大,密度和抗拉强度提升越明显;在热等静压温度(490℃)、压力(100 MPa)不变条件下,保温时间超过2h,铸件密度增加幅度较小;而在热等静压温度(490℃)、时间(2h)不变条件下,当热等静压压力超过临界值(100MPa)后,铸件抗拉强度提升不明显。     

热等静压对电子封装60wt%Si-Al合金组织与性能的影响

采用喷射成形技术制备了新型电子封装材料60wt%Si-Al合金,选用两种热等静压工艺对其进行致密化处理,研究热等静压对材料组织和性能的影响。观察、分析了热等静压致密化后合金组织,测试了热等静压后合金的致密度、导热及热膨胀性能。结果表明,热等静压可有效减少或消除喷射成形60wt%Si-Al合金坯件内部的缩松缩孔,使合金接近理论密度。固态(520℃)热等静压后的合金相比半固态(600℃)热等静压合金,表现出更高的致密度、热导率和更低的热膨胀系数。     

热等静压对铸态及固溶态第二代镍基单晶高温合金显微缺陷及持久性能的影响

以初始组织分别为铸态组织和固溶态组织的第二代镍基单晶高温合金为研究对象,通过进行1300℃、30 MPa、2 h+1300℃、100 MPa、3 h两阶段的热等静压处理,对比热等静压前后显微缺陷及微观组织的变化,并在980℃、250 MPa条件下进行高温持久性能实验,明确了热等静压处理对不同初始组织状态下镍基单晶合金组织状态及持久性能改善的影响机制。结果表明:固溶处理显著促进Re、W、Al、Ta等合金元素的扩散,降低铸态组织共晶面积分数但显著提高显微孔洞平均面积分数及平均尺寸。热等静压处理可以显著降低显微孔洞平均面积分数及平均尺寸且对固溶态组织的作用更为显著,但热等静压对共晶组织的消除作用不如固溶处理明显。固溶态组织经热等静压处理后,显微孔洞面积分数降低至0.005%;共晶组织基本消除;Re、W、Al、Ta等元素枝晶偏析程度显著缓解;其980℃、250 MPa高温持久寿命相比未经热等静压处理的标准热处理态合金提高了40%左右。对固溶态组织进行热等静压处理的工序安排有利于提高显微孔洞闭合作用,促进成分均匀化并显著提高合金高温持久寿命。     

热等静压对SEBM成形TC4钛合金性能的影响分析

由于选区熔化成形的TC4钛合金致密程度不高，因此针对电子束选区熔化技术（SEBM）成形的TC4钛合金，随炉进行热等静压试验，研究分析热等静压处理后合金的微观组织和力学性能。结果表明，经过热等静压处理后的TC4钛合金试件通过排水法测试出的相对密度达到了99%以上，几乎完全致密。对拉伸试样并进行室温拉伸试验，热等静压处理后的试件呈现出抗拉强度下降，塑性提高的趋势，抗拉强度为640.49 MPa，低于SEBM成形件的760 MPa，断裂伸长率达到19.95%。试样断口呈现被拉长的杯锥状及数量少、形状大且深的韧窝。热等静压过处理后的试件呈现出网篮组织，整体均匀细致，在β晶界内密集的片状α相互交错分布，且伴随着等轴α相。     

热处理工艺对高铁耐蚀60Si2Mn弹簧钢组织和性能的影响

在常规高铁弹条60Si2Mn弹簧钢基础上,通过添加Cr、Ni、Cu等耐蚀元素设计了耐蚀60Si2Mn弹簧钢,研究了热处理工艺对耐蚀弹簧钢显微组织、力学性能的影响规律,并评价了其耐蚀性能。结果表明,淬火+回火处理后耐蚀60Si2Mn钢显微组织为回火屈氏体,870 ℃保温45 min,油淬+440 ℃回火60 min处理后,耐蚀弹簧钢的综合力学性能最佳,屈服强度为1606 MPa,抗拉强度为1716 MPa,断后伸长率为5.3%,洛氏硬度为50.2 HRC。添加耐蚀元素的60Si2Mn钢耐蚀性较常规60Si2Mn钢得到较大提升。     

低合金高强度抗应力腐蚀开裂海洋软管用钢的开发

通过合金成分设计,轧制、热处理工艺的探索,开发了低合金高强度海洋软管用钢,其屈服强度大于600 MPa且满足抗氢脆、抗氢致开裂、抗应力腐蚀开裂性能,并通过全浸腐蚀实验对该钢的海水腐蚀行为进行了研究。结果表明,采用低C、低Mn并复合添加耐蚀元素Cr、Mo和采用合理的热轧、冷轧、调质处理工艺,可获得满足抗应力腐蚀开裂性能的600 MPa级高强钢。耐蚀元素的添加使实验钢具有良好的耐海水腐蚀能力,腐蚀稳定状态下的平均年腐蚀速率为0.11 mm/a。     

固溶温度对2507双相不锈钢力学性能及耐蚀性的影响

利用光学显微镜、扫描电镜、XRD、拉伸试验机和电化学综合测试仪等研究了不同固溶温度对2507超级双相不锈钢组织、力学性能和耐蚀性的影响。采用Thermo-Calc热力学软件计算了2507双相不锈钢的热力学平衡相图,并与测试结果进行了对比。研究结果表明,经1050 ℃及以上温度固溶后,σ相溶解;随着固溶温度的升高,铁素体相含量增加,奥氏体相含量降低,α/γ相体积分数比增加;1050~1100 ℃固溶30 min并水冷时,双相不锈钢具有较好的综合力学性能,屈服强度、抗拉强度和伸长率分别大于600 MPa、840 MPa和35%。1050 ℃固溶30 min时,双相钢可获得较好的耐蚀性能。     

L450MS+No8825复合不锈钢板轧制工艺研究

在生产试验条件下,采用控轧控冷工艺试制了L450MS管线钢+No8825奥氏体镍基合金复合板。通过加大道次变形量,提高轧后钢板冷却速率,保证了L450MS管线钢综合性能,其屈服强度达484～542 MPa,抗拉强度达544～593 MPa,伸长率达45%～50%,-30℃纵向冲击功达300 J以上,同时No8825奥氏体镍基合金与L450MS管线钢基体复合良好,既保留了不锈钢的耐蚀、耐磨、抗磁性能以及外表美观的特点,又兼具管线钢良好的可焊性、成形性、拉伸性、导热性的特点,提高了设备的抗腐蚀能力,延长了设备的使用寿命,降低了企业生产成本。     

690MPa级高强韧低碳微合金建筑结构钢设计及性能

基于JMatPro热力学软件计算并考虑化学元素间相互影响,设计了690 MPa级抗震耐蚀防火功能结构一体化高强建筑用钢,其化学成分(质量分数,%)主要为:Fe-0.08C-0.3Si-1.1Mn-0.12(Nb+V+Ti)-1.6(Cr+Cu+Ni+Mo)-0.002B-0.004N。经实验室冶炼和控轧控冷工艺(TMCP)处理后,采用EPMA、EBSD等多种微观分析和性能测试手段对该低碳微合金钢的微观组织特征、强韧化机理和力学性能、防火性及耐蚀性等进行了表征和分析。结果表明,所设计的低碳微合金钢TMCP状态下的微观组织包含粒状贝氏体、板条贝氏体和贝氏体铁素体;室温下屈服强度达700 MPa,抗拉强度为878 MPa,屈强比为0.80,断后延伸率为20%,并具有良好的低温韧性。低碳微合金钢在600℃保温1~3 h时,均达到耐火性能要求;并对其在海洋环境下的耐蚀性进行了评价,发现粒状贝氏体对耐腐蚀性能具有积极作用。进一步分析表明,低碳微合金钢具有良好的强韧性源于析出强化、细晶强化、位错强化和固溶强化的综合作用;对低温冲击断口截面组织分析表明,裂纹会多次穿过板条贝氏体呈"Z"字型扩展以消耗更多的能量,也是该钢具有良好低温韧性的原因。     

终锻温度对核电用316L奥氏体不锈钢组织性能的影响

采用光学显微镜、电子万能试验机和晶间腐蚀试验等研究了终锻温度对核电用316L奥氏体不锈钢显微组织、力学性能及耐晶间腐蚀性能的影响.结果表明:当始锻温度为940℃,终锻温度为830℃时,试验钢的晶粒度为4.5～5级,比终锻温度860℃和890℃的样品分别高0.5级和1级.终锻温度为830℃的样品在室温下抗拉强度达到574...     

高强不锈钢激光熔覆层的组织与性能

针对核装备零部件维修再制造的需要,采用激光熔覆技术制备高强韧马氏体不锈钢熔覆层,以改善核装备零部件的表面性能,随后对熔覆层试样分别进行300 ℃和500 ℃保温2 h的回火处理。采用OM、SEM、显微硬度计、万能拉伸试验机等设备测试了试样的组织和性能。结果表明,原始试样的抗拉强度为1719 MPa,断后伸长率在15%左右,硬度为550 HV0.2,耐磨性较差;当回火温度为300 ℃时,出现逆转变奥氏体,硬度降至500 HV0.2,抗拉强度降为1662 MPa,断后伸长率超过15%,耐磨性提高;当回火温度上升到500 ℃时,逆转变奥氏体减少,碳化物逐渐析出,出现二次硬化,硬度又上升至530 HV0.2,抗拉强度降至1582 MPa,断后伸长率降至14%左右,耐磨性与原始试样相当。该高强马氏体不锈钢熔覆层整体耐腐蚀性均优于1Cr13钢,具有良好的耐腐蚀能力。     

Microstructure and Mechanical Properties of 1,000 MPa Ultra-High Strength Hot-Rolled Plate Steel for Coal Mine Refuge Chamber

The 1,000 MPa ultra-high strength hot-rolled plate steel with low-carbon bainitic microstructure was developed in the laboratory for coal mine refuge chamber. The static recrystallization behavior, microstructure evolution, and mechanical properties of this hot-rolled plate steel were investigated by the hot compression, continuous cooling transformation, and tensile deformation test. The results show that the developed steel has excellent mechanical properties at both room and elevated temperature, and its microstructure mainly consists of lath bainite, granular bainite, and ferrite after thermal–mechanical control process(TMCP). The ultra-high strength plate steel is obtained by the TMCP process in hot rolling, strengthened by bainitic transformation, microstructure refinement, and precipitation of alloying elements such as Nb, Ti, Mo, and Cu. The experimental steel has relatively low welding crack sensitivity index and high atmospheric corrosion resistance index. Therefore, the developed steel has a good balance of strength and ductility both at room and elevated temperature, weldability and corrosion resistance, and it can suffice for the basic demands for materials in the manufacture of coal mine refuge chamber.     

Vergleich des SwRK-Verhaltens eines auf hohe Duktilität vergüteten martensitaushärtenden PH 13-8 Mo Stahls mit dem Dampfturbinenlaufschaufelstahl X20 CrMoV 12 1

Corrosion fatigue behaviour of the to high ductility aged precipitation hardened steel PH 13-8 Mo and the X20 CrMoV 121 steam turbine blading steel in comparison The corrosion fatigue behaviour of the martensitic stainless steels PH 13-8 Mo and X20 CrMoV 121 is compared. The investigation includes both electrochemical and corrosion fatigue tests. Also mechanical, metallographical and SEM investigations were performed. The corrosion fatigue resistance at 150°C of the precipitation hardened steel PH 13-8 Mo in the modification with the higher strength level (cast I) varies between 100 and 135 MPa. The mean stress was 250 MPa. The influence of the pH-value is predominant to the Cl^? -concentration. The corrosion fatigue resistance of the lower strength modification of PH 13-8 Mo (cast II) is significant lower than that of cast 1. At the conventional 12% Cr-steel cracks are initiated from notches caused by corrosion under salt like deposits primarily at the grain boundaries, weakened by carbide precipitations. At the PH 13-8 Mo steel the crack initiation is located at zones of plastic deformation between the martensitic laths. Corrosion attack occurred preferably by orthogonal orientation of the laths to the surface.     

Effect of Interlayers on Microstructure and Properties of 2205/Q235B Duplex Stainless Steel Clad Plate

In this research,2205/Q235 B clad plates were prepared by a vacuum hot rolling composite process.The effects of adding Fe,Ni,and Nb interlayers on the bonding interface structures and the shear strengths of the clad steel plates were studied.The results showed that 2205 duplex stainless steel and the three interlayers produced a large amount of plastic deformation and low-angle boundaries,and the main structures were the recrystallized and deformed grains.There were many recrystallized grains in the microstructure of the Q235 B low-carbon steel due to the low deformation in the rolling process.The Fe interlayer had better wettability with the two kinds of steel,but the lower strength led to the reduction of shear strength by about14 MPa compared with the original clad steel plate.The C element in the Q235 B low-carbon steel easily diffused into the Fe interlayer,and the clad steel plate attained a poor corrosion resistance because a large decarburization area was formed.The Nb interlayer reacted with the Mo element in the 2205 duplex stainless steel to form an Nb-Mo binary alloy,which generated long-banded ferrite.The decarburization area was also produced because the Nb reacted with the C element in the Q235 B to form hard and brittle NbCx.As a result,the shear strength was significantly reduced by about 282 MPa,and the corrosion resistance of the bonding surface was deteriorated.The Ni interlayer did not react with the alloy elements in both sides,and therefore effectively prevented element diffusion and improved the corrosion resistance of the bonding surface.Due to the low strength of the Ni interlayer and the increased number of bonding surfaces of the clad steel plates,the shear strength was reduced to some extent(about 40 MPa),but it still met the engineering application standards.