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Now the soft composites are applied in the automobiles and household appliances such as ABS brake motors, refrigerator compressor motors and brushless servo motors. The process of iron powder soft magnetic composites in recently years was introduced which includes the preparation of iron powder, insulating coating, compression and heat treatment. And then the main properties of soft magnetic composites were summarized. At last some opinions on following researching directions were pointed out.     

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The quality of strip cannot meet the requirements of various industries at present, one of the main reasons is that the plate-profile automatic control system is imperfect and researches in signal detection, signal processing, plate-profile pattern recognition are lag, which will make it become the weak link in flatness control. The research achievements of plate-profile signal detection, plate-profile defect discrimination and flatness control for cold-rolled strip was introduced. The advantages and disadvantages of these researches are compared and the development directions are put forward.     

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The gasification behavior of different iron cokes was studied in laboratory by the means of thermogravimetry technique, the temperatures at which iron cokes start to react with CO2 were measured, and theoretical analysis was conducted with the FactSage thermodynamic software. The results show that the higher the metallic iron content in iron coke, the higher the gasification rate, and it increases with the increasing temperature; metallic iron can promote the decrease of starting temperature of gasification reaction, and the higher the metallic iron content, the more the decrease extent of gasification starting temperature; at the initial stage of gasification reaction, metallic iron in iron coke is oxidized by CO2, as a result, the weight of samples not only decrease but also increase.     

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Laser additive manufacturing(LAM) is a new type technology combined with laser science, digital science and material science, it has many advantage, such as dimensionality reduction manufacturing, complex shapes manufacturing, and high utilization ratio of materials. According to the way of material inputting, it can be divided into selective laser melting(SLM) technology and laser melting deposition(LMD) technology. Laser additive manufacturing parts with fine grains and homogeneous microstructure has been widely used in aerospace field, due to its excellent mechanical properties. Recent developments in Ni- based laser additive manufacturing technology have been reviewed in the following aspects: technical principles, microstructure, mechanical properties, and density. It is noted that lightweight design and integration of structure- function may be the development tendency of laser additive manufacturing in the future.     

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In the steel strip cold rolling process, the thermal crown of rollers affects the transverse thick difference and the strip flatness. But it is difficult to be measured on line. Through the establishment of transverse thickness difference equation and thermal crown tracing analysis, the change rule of roll thermal crown hide in this mass of process data was found out, and was used to predict and compensate it online. This method was used in the 300 testing cold rolling mill, and compared with the traditional rolling process. The test results show that the prediction is reasonable, and the compensation is effective to level off transverse thick difference.     

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The sintering basic performance of iron ore fines and its research status were overviewed, the existing research methodologies and techniques of sintered ore blending were analyzed, and the further development and improvement of sintering optimization ore matching was prospected. It is suggested that the establishment of integrated comprehensive system of sintering ore, which is based on the iron ore sintering performance, is one of the development direction of sintering optimization ore matching. It should make full use of advantages of neural networks and Matlab mathematical software to develop the expert system for sintering optimization ore matching.     

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The pore distribution of low silica sinter samples with different C was measured by pressure mercury, and the fractal characteristic of pore distribution was calculated with multifractal theory. With the amount of C increasing, ???? is the least when the mass percent of C is 3. 7%, furthermore, the value of ??f(??) changes from negative to positive in the vicinity 3. 7%, the number of maximum probability element increases relatively, so the sinter has good multiple fractal structure and fractal features. If the amount of C continues increasing, the size of pores will drop, then fractal features will becomes less pronounced. The results also show when the mass percent of C is 3. 7%, its metallurgical properties is optimal.     

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MS980 is one of advanced high-strength steels, which has a great potential for producing square tubes. Residual stress plays a significant role in determining roll-formed members?? behavior and strength. An experimental study on transverse residual stress of roll-formed shape with square section was conducted via X-ray diffraction method. The distribution of transverse residual stresses at different position in sections was measured and studied, and influence of cold-rolled-sheet and hot-rolled-sheet, different fillet radius, different processes, and different pickling time on circumferential residual stress distribution for square section was investigated. The experimental results show the transverse residual stresses are compressive stress in the corner portion and the tensile stress in the straight edge. Fillet radius, sheet, and process have a significant impact on the distribution of residual stress, but the conventional pickling hardly affects residual stress.     

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The scale composition, mass percent and thickness of high carbon steel wire rod were investigated under different rolling and laying temperatures in order to improve the mechanical descaling property of high carbon steel wire rod. Effects of rolling and laying temperatures on scale properties were studied by using thermodynamics and kinetics of scale formation and growth. The works can provide technological supports for industrial practices. The requirement of customers is satisfied.     

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The material selection ,development and localization about steam generator (SG) tube of unit in pressurized water reactor (PWR) in China in recent decades were reviewed. Through serious of research and technology breakthrough, a lot of data about material performance were accumulated. And an SG tube material with completely independent intellectual property right was developed successfully by China, which bears excellent SCC and pitting corrosion resistant properties. The industrialization ability of domestic Inconel 690TT etc. tube has been built, which have been used in China. All of these above strongly promote the localization process of critical material in nuclear power.     

微合金元素Ti-Nb对低碳贝氏体钢组织和力学性能的影响

试验的700 MPa级低碳贝氏体钢由30 kg真空感应炉熔炼铸成断面100 mm×50 mm扁锭-轧成12mm板。通过CCT曲线和3～30℃/s冷却速度下组织的分析,研究0.01Ti-0.03Nb和0.06Ti-0.05Nb两种微合金化对(%)0.059～0.066C、1.41～1.67Mn、0.30～0.36Si、0.37～0.48Cu、0.21～0.24Ni、0.18～0.22Mo、0.000 8～0.002 2Bs、0.002 6N低碳贝氏体组织和力学性能的影响。结果表明,0.06Ti-0.05Nb钢的强度高于0.01Ti-0.03Nb钢,但前者Ti含量高,-40℃冲击功较后者低。700 MPa级低碳贝氏体钢合适的微合金化Ti-Nb成分为0.04%～0.05%Nb-0.015%～0.025%Ti。     

Nb微合金化低碳贝氏体钢的再结晶和应变诱导析出

通过Gleeble-2000热模拟试验机研究了850～1 050℃双道次变形(第1道次60%,20 s-1,第2道次20%,10 s-1)及不同道次间隔时间(10～50 s)对含铌低碳贝氏体钢(%:0.21C、1.50Cr、0.20Mo、0.047Nb)再结晶的影响和应变诱导析出Nb(CN)与热变形奥氏体再结晶的相互作用.结果表明,该钢在1 000～900℃变形10 s后,开始应变诱导析出Nb(CN),延迟静态再结晶过程;通过双道次变形,可获得≤10 μm奥氏体晶粒.     

抽油杆用超高强度贝氏体非调质钢的研制

所研制的新型超高强度非调质贝氏体钢为唐山钢铁公司开发的低碳Mn-Mo系V－Ti微合金化非调贝氏体钢FG20的改型钢种，新型钢主要成分（％）为：＜0．16C，1．0－2．0Mn,1.0-3.0Si,1.0-2.5Cr,0.1-0.3Mo,0.05-0.10V,0.03-0.06Ti，该钢热轧材经580℃回火后，强度极限为1020－1100Mpa，延伸率大于12％。     

钒微合金化低碳贝氏体钢的连续冷却相变特性

 采用热膨胀法测定6种不同成分低碳贝氏体钢的连续冷却转变(CCT)曲线。CCT曲线表明,加入微量硼能使含钒低碳贝氏体钢在大于03℃/s的冷速下获得贝氏体组织,而V-N微合金化的低碳贝氏体获得全贝氏体的临界冷速要高于V-B钢,且贝氏体转变的开始温度也要较V-B钢高20℃左右。在含钒、氮低碳贝氏体钢中加入钼、铬将会促进钢的贝氏体相变,但钼的作用要优于铬;钼、铬的加入可使含钒、氮低碳贝氏体钢的贝氏体转变温度降低至少30℃,且贝氏体组织得到了细化,钢的维氏硬度也提高了HV10~30。     

Ti-Nb微合金化对低碳高强度钢组织和性能的影响

0.153Ti-0.038Nb和0.080Ti-0.062Nb两种Ti-Nb微合金化低碳钢(/%:0.061～0.075C、0.22Si、1.76～1.77Mn、0.002～0.003S、0.006P、0.003Als、0.003 8～0.004 2N、0.004 0～0.004 5O)由50 kg真空感应炉冶炼,轧成10 mm板,终轧温度880℃,水冷至630℃。试验结果表明,两种Ti-Nb微合金化钢的析出物均为(Nb,Ti)(C,N)复合析出物;当Ti含量由0.080%增加至0.153%,同时Nb含量由0.062%降至0.038%时,钢屈服和抗拉强度分别从558 MPa和653 MPa提高至633 MPa和756 MPa,屈强比、伸长率和断面收缩率变化较小。表明,添加Ti代替部分Nb进行复合微合金化可提高钢材强度,降低生产成本。     

600 MPa级Nb-Ti微合金高强度钢的开发

开发的Nb-Ti微合金高强钢(/%:0.04C、0.34Si、1.40Mn、0.010P、0.004S、0.098Nb、0.020Ti、0.045Al、0.002 5N)由真空感应炉冶炼、50 kg钢锭40 mm锻造板坯经试验室单架轧机于1 200℃7道次轧制成10mm板,末道次压缩比≥15%,终轧温度880℃,喷水冷却至600℃,置于热处理炉600℃30 min,炉冷至室温,分别模拟层流冷却和卷取工艺。该钢经Gleeble 3500热模拟机试验得出,高温低塑性区为650～800℃和≥1 300℃。力学性能试验结果为下屈服强度R_el625～640 MPa,抗拉强度R_m705～710 MPa,伸长率18.0%～19.5%。所开发的钢具有碳当量低,焊接性能好,成本低等特点。     

超低碳高强度Q550D贝氏体钢的研制

利用超低碳和微合金化的成分设计,采用TMCP(Thermomechanical Controlled Proces)-T(Tempering)工艺,充分利用晶粒细化和针状铁素体与粒状贝氏体组织强化等手段,辅以回火处理工艺,在工业试制条件下得到韧性良好,屈服强度为550 MPa级的超低碳贝氏体钢。     

微合金化HRB400高强度热轧钢筋的试制

HRB400高强度钢筋(％:0.19～0.25C、0.40～0.60Si、1.20～1.50Mn、≤0.040P、≤0.040S)由120 t转炉—钢包吹氩-120 mm×120 mm连铸工艺冶炼.为提高HRB400Φ12 ～22 mm热轧带肋钢筋的综合力学性能,冶炼时进行加5 kg/t钢MnSiN+0.4～0.9 k...     

空冷低碳贝氏体钢DB590的组织和性能

试验用空冷低碳贝氏体钢DB590(%:0.06C、0.92Mn、0.49Mo、0.65Cr、0.02Nb、0.08V、0.001 0B)由50 kg真空感应炉熔炼、铸成22 kg锭、锻成(mm)100×100×150钢坯,并控制轧成16 mm板,空冷。通过Gleeble 1500热模拟机得出该钢的CCT曲线。DB590钢轧后空冷(3℃/s)的组织为贝氏体+铁素体基体,钢板的抗拉强度645 MPa,屈服强度471 MPa,伸长率32%,0℃冲击功94 J以及优良的冷弯性能。     

安钢Nb微合金化高强度船体结构钢板的开发

安阳钢铁公司通过100 t转炉-100 t LF-200 mm×1 500 mm连铸机-2800 mm中板轧机生产流程开发了Nb微合金化高强度船板。生产数据统计结果表明,通过精确控制钢的成分(%:0.13～0.16C、0.33～0.43Si、1.31～1.42Mn、0.007～0.014P、0.005～0.0185、0.021～0.039A1、0.018～0.022Nb),精轧开始温度950℃,精轧累积压下率≥50%,终轧温度780～850℃,使AH36牌号6～25 mm钢板的晶粒度为9～9.5级,屈服强度360～475 MPa,抗拉强度490～610 MPa,δ5伸长率18%～36%,0℃冲击功110～221J。