含锡易切削钢的冶炼和性能研究

以锡替代铅，用20k感应炉熔炼了成分(％)为：0．20～0．21C，0．56～0．60Si，0．78～0．80Mn，0．28-0．29S，0．066～0．070P，0～0．049Sn易切削钢。试验结果表明，加锡可以明显改善钢的切削性能，经60min切削，高速钢刀具后刀面磨损宽度(Vb)由切削未加Sn钢的0．60唧降到切削加Sn钢的0．45mm。加锡钢的力学性能与含铅易切削钢相当。扫描电镜和能谱对钢中夹杂物和断口分析表明，在含锡钢的晶界和夹杂物附近锡偏聚显著。     

易切削非调质塑料模具钢的研究

研究了易切削系非调质塑料模具钢的组织与性能。本钢种无需经过任何热处理，经锻轧后空冷就能达到较好的强韧性。通过切削、磨削、抛光等实验证实该材料具有良好的加工性能。利用光学显微镜、电子显微镜以及电子探针等仪器观察与分析了显微组织特征和易切削相，并探讨了其易切削机理。     

硫易切削齿轮钢的开发

多年来我厂一直存在行星齿轮加工难问题,尤为突出的是钻孔工序与铣齿工序,经常出现打刃现象.影响齿轮加工的因素主要有3个方面:齿轮材料、齿轮毛坯的硬度及显微组织、加工齿轮的刀具.国外在解决齿轮加工难问题上,也是从这3个方面着手,如德国大众公司为使捷达传动器齿套好加工,采用一种硫含量很高的齿轮材料TL4126(28MnCr5S),毛坯采用等温退火.     

Microstructure and Mechanical Properties of NANOBAIN Steel

The microstructure and mechanical properties of NANOBAIN steel treated at different isothermal temperatures were investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM),uniaxial tensile tests and X-ray diffraction(XRD).It was found that bainitic ferrite(BF)plate was made of basic shear transformation units arranged in the same direction of subunits.The existence of defects,such as nanoscale twinning and dislocation,suggested that the growth of transformation units was controlled by the surrounding defect plane with dislocation,which was consistent with the moving direction of BF/austenite interface parallel to the twinning plane.The behavior of work hardening indicated that mechanical stability of microstructures obtained at 250 ℃ and 300 ℃ was much more stable than that obtained at 210℃.The evolution of carbon partitioning in retained austenite and bainitic ferrite also indicated that austenite was enriched in carbon at the initial stage step by step;after the formation of BF,the austenite did not seem to be greatly enriched in carbon and the carbon content showed a little decrease instead;subsequently,aphenomenon of little decarburization of supersaturated bainitic ferrite has also been found.     

Microstructure and Mechanical Properties of TWIP Steel Joints

As a new type of high manganese steel, the twinning induced plasticity （TWIP） steels have attracted a growing interest in the automotive industry due to their good performance. Thin plates of TWIP steel were welded by laser beam welding （LBW） and gas tungsten arc welding （GTAW）. The microstructure result shows that GTAW joint has obvious heat-affected zone （HAZ）, while the HAZ of LBW joint is almost invisible. The X-ray diffraction result shows that the phase compositions of both joints are austenitic and no phase transition occurs. Energy disper- sive spectrometry result shows that there is violent evaporation of Mn element in LBW joint, while the proportion of Mn element in GTAW joint is almost unchanged. Tensile tests and micro-hardness measurements were performed to take into account the mechanical properties of joints manufactured by the two different processes. The micro-hard- ness profiles of both joints present a typical saddle distribution, and the hardness of GTAW seam is lower than that of LBW seam. The failure positions of LBW joints are all located in base metal while the GTAW joints are all at the weld toe due to the softening of HAZ. By means of scanning electron microscopy, a typical ductile fracture is observed in LBW joint, while a brittle fracture with quasi-cleavage fracture characteristic is observed in GTAW joint.     

控轧直接淬火钢的微观组织与力学性能

分析了22SiMn2TiB钢再结晶控轧直接淬火(RCR&DQ)、未再结晶控轧直接淬火(CR&DQ)以及两者重新调质后(CR&DQQ、RCR&DQQ)的微观组织和力学性能。同时,与传统再加热淬火处理(RA&Q)的组织和性能进行了对比,结果表明:试验钢直接淬火后强硬度明显高于再加热淬火钢,塑性基本相当,而韧性也得到了较大幅度的提升。     

以锡代铅研制环保型易切削钢

以锡代铅研制了一种含锡的环保型易切削钢,并进行了切削及力学性能试验.结果表明,在含量小于0.05%(质量分数)时,锡能明显改善钢的易切削性能,未发现对钢的力学性能有不利的影响.     

环保型含Bi低碳高硫易切削钢的开发

开发Bi易切削钢1215M(%:0.06C、0.04Si、1.25Mn、0.39S、0.17Bi)替代Pb易切削钢SUM24L。生产Bi易切削钢的流程为40t UHP EAF-40t LF(喂Bi线)-180 mm×180 mm连铸-连轧工艺。试验结果表明,Bi易切削钢1215MΦ9 mm盘条夹杂物分布均匀,Bi易切削钢1215M的切削性能优于SUM23HS含S易切削钢与SUM24L含Pb易切削钢相当。     

硫系易切削钢氧化物和硫化物变性的分析

通过分析和研究影响硫系易切削钢加工性能的一个重要因素-钢中氧化物和硫化物的组成、特性和分布形态，提出了硫系易切削钢的冶炼钙处理工艺优化技术，即应首先对铜液中的氧化物进行变性处理，然后再进行硫化物的变性处理。     

Microstructure and Mechanical Properties of High Manganese TRIP Steel

 Abstract： Microstructure evolution and mechanical properties of newly designed 01C-6Mn-05Si-1Al TRIP-aided steels under different annealing conditions and the effects of matrix microstructure before intercritical annealing on the final microstructure were studied by means of X-ray diffraction (XRD), scanning electron microcopy (SEM), dilatometric simulation, optical microstructure (OM) and tensile testing in this work. The experimental results indicate that the TRIP steel with Mn of 6% could form a considerable amount of retained austenite with good TRIP effect after a simple intercritical annealing treatment, and the matrix microstructure before intercritical annealing treatment can greatly affect the final microstructure. The original microstructure of the ferritic matrix steel was eliminated, while annealed martensite was remained from the martensite matrix steel under the same intercritical annealing conditions.     

超高碳钢的回火组织及力学性能

用CM200型透射电子显微镜研究了超高碳钢双相区淬火 中、高温回火后的组织,用Instron型拉伸试验机测定了力学性能.结果表明:650℃的回火组织为等轴状的铁素体与球状的渗碳体,屈服强度σ0.2=1127MPa,抗拉强度σb=1 266 MPa,均匀伸长率δu=8.26%,总伸长率δt=9.71%,维氏硬度HV为397;450℃回火组织的铁素体保持淬火的形态,回火碳化物为ε碳化物在基体上以断续的片状析出,σ0.2=1 911 MPa,σb=2 028MPa,δu=δt=1.88%,HV为595;400℃回火组织中的铁素体保持淬火的形态,回火碳化物在位错处几乎呈网状析出,拉伸无塑性,HV为703.     

V-Ti-N耐大气腐蚀钢组织性能研究

采用真空感应炉、热模拟试验机、ICP发射光谱仪、光学显微镜、TEM和电子拉伸试验机等设备,研究了V-Ti-N耐大气腐蚀钢(0%V、0.05%V、0.10%V和0.15%V)的动态CCT曲线、析出钒、晶粒尺寸和强度。结果表明:在耐大气腐蚀钢中添加0.10%V,对CCT曲线的影响有限,贝氏体转变温度都低于600℃;V-Ti-N耐大气腐蚀钢的晶粒尺寸为6.2~7.8μm,产生了101~175 MPa的沉淀强化,屈服强度随着钒氮积的增加而升高,但强化效率逐渐降低;V-Ti-N微合金化较适合于生产400 MPa和450 MPa级高强度耐大气腐蚀钢,此时,钒含量应小于0.10%。     

新型耐蚀塑料模具钢的组织和性能

 研究了w(C)=039%和w(C)=053%的2种Cr17Mo型耐蚀塑料模具钢的组织、力学性能及耐蚀性能。实验结果表明：2种钢材经适当的淬、回火处理后,均具有较高的硬度和强度;在弱酸和氧化性酸(醋酸和硝酸)中,均具有良好的耐腐蚀性能。     

亚共析石墨化易切削钢的开发

 石墨易切削钢是顺应易切削钢无铅、低硫这一发展趋势而提出的。具有亚共析组织的钢种其石墨化过程一直很难,因此该钢种开发的关键是促进其石墨化过程。基于增加石墨核心来加速石墨化过程进行了钢种的成分设计与研制。结果表明,正是开发钢中具有与石墨结构（简单六方）相同的BN成为了石墨的形核位置,从而有效促进了开发钢的石墨化过程。开发钢的组织由铁素体和石墨组成,其中,石墨的缺口效应和润滑效果赋予了开发钢较高的切削性能和冷成形性能。     

低碳贝氏体钢的组织类型及其对性能的影响

低碳贝氏体钢受控冷工艺的影响会得到不同类型的组织，在较慢速冷却时，在奥氏体中先形成针状铁素体，残余奥氏体会被包裹在铁素体之中，形成粒状贝氏体团。工业轧制试验表明．不同控制冷却工艺可得到两类组织，一类出现黑珠组织(富碳马氏体组织)．具有该组织的钢轧态冲击韧性低。另外一类为细化的板条贝氏体组织，具有该组织的钢轧态强度高，冲击韧性好，但伸长率不足。通过回火处理，存在黑珠组织钢的冲击韧性能得到提高，超细化板条贝氏体组织钢的伸长率也能得到改善，但后者屈服强度会比前者高100MPa左右。     

高马氏体量双相钢的组织与性能研究

通过光镜、扫描电镜分析以及拉伸试验研究了高马氏体量双相钢(马氏体体积分数大于30%)在不同热处理条件下的显微组织和拉伸性能,并进一步探讨了其断裂机理.结果表明,随着两相区保温温度的升高,马氏体体积分数不断升高,导致强度不断提高.马氏体体积分数较低时,钢的断裂特征为韧性断裂;马氏体体积分数较高时,则会转变为脆性断裂.微孔在断裂表面附近形成.微孔的形态随着马氏体的比率而变化,随着马氏体体积分数的升高,微孔形态从界面结合力的丧失转为微裂纹.     

高性能渗碳轴承钢的组织与性能

 研究了热处理工艺对渗碳轴承钢组织、力学性能的影响规律,并探讨了强韧化机制。研究表明,随着淬回火温度升高和回火次数增加以及采用深冷工艺,渗碳轴承钢的强度与硬度增加,冲击韧性值下降。采用910℃淬火和180℃二次回火,轴承钢材料性能可达到硬度HRC452,抗拉强度Rm为1450MPa,屈服强度ReL为1240MPa,AKU为105J,残余奥氏体的体积分数控制在1%以下。试验钢良好的强韧性配合主要来自于晶粒的细化、超细马氏体板条和均匀弥散的细小碳化物的析出;尺寸稳定性的效果主要是残余奥氏体量的控制。     

Microstructure and Mechanical Properties of Martensitic High-Strength Engineering Steel

Metallurgist - A promising martensitic steel with good hardenability is studied. In the cooling rate range 0.1–30°C/sec and the only transformation recorded by a dilatometer starts at an...     

Microstructure and Mechanical Properties of Hot-Rolled Fe-Mn-C-Si TWIP Steel

 Mechanical properties and microstructural evolution of the hot-rolled Fe-Mn-C-Si TWIP steel were investigated and the deformation mechanism was analyzed. The results showed that the tensile strength and elongation were about 1050 MPa and 60%, respectively. The hot-rolled steel had high specific energy absorption and impact toughness between -120 ℃ and 20 ℃. Some inhomogeneous dislocation zones were observed in the undeformed steel. Lots of deformation twins and twin-dislocation interactions were observed in the deformed steel. TWIP effect was the major deformation mechanism for the excellent mechanical properties.     

TiC强化304不锈钢的显微组织和性能

对原位合成TiC强化304不锈钢的显微组织和性能进行了研究。试验结果表明:在304不锈钢中产生TiC颗粒后,热处理态组织中的孪晶得到明显细化,同时出现了很多纳米级的未固溶的方形颗粒Cr23C6和圆形颗粒TiC。TiC颗粒的产生,使304不锈钢强度有较大提高而塑性有一定的下降。在TiC强化钢磨损过程中,TiC颗粒暴露于磨损表面起承载和形成油膜的作用,从而保护基体不发生严重磨损。随着钢中TiC含量的增加,强度和磨损性能的提高越明显。