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High-cycle Fatigue Fracture Behavior of Ultrahigh Strength Steels

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Journal of Materials Science & Technology 2008年第5期24卷 787-792页

作者： Weijun HUI Yihong NIE Han DONG yuqing weng Chunxu WANG State Key Laboratory of Advanced Steel Processing and Products Beijing 100081 China National Engineering Research Center of Advanced Steel Technology Beiing 100081 China Yanshan University Qinhuangdao 066004 China The Chinese Society for Metals Beijing 100711 China

The fatigue fracture behavior of four ultrahigh strength steels with different melting processes and therefore different inclusion sizes were studied by using a rotating bar two-point bending fatigue machine in the high-cycle regime up to 107 cycles of loading. The fracture surfaces were observed by field emission scanning electron microscopy （FESEM）. It was found that the size of inclusion has significant effect on the fatigue behavior. For AtSI 4340 steel in which the inclusion size is smaller than 5.5 μm, all the fatigue cracks except one did not initiated from inclusion but from specimen surface and conventional S-N curve exists. For 65Si2MnWE and Aermet 100 steels in which the average inclusion sizes are 12.2 and 14.9 μm, respectively, fatigue cracks initiated from inclusions at lower stress amplitudes and stepwise S-N curves were observed. The S-N curve displays a continuous decline and fatigue failures originated from large oxide inclusion for 60Si2CrVA steel in which the average inclusion size is 44.4 pro. In the case of internal inclusion-induced fractures at cycles beyond about 1×10^6 for 65Si2MnWE and 60Si2CrVA steels, inclusion was always found inside the fish-eye and a granular bright facet （GBF） was observed in the vicinity around the inclusion. The GBF sizes increase with increasing the number of cycles to failure Nf in the long-life regime. The values of stress intensity factor range at crack initiation site for the GBF are almost constant with Nf, and are almost equal to that for the surface inclusion and the internal inclusion at cycles lower than about 1×10^6. Neither fish-eye nor GBF was observed for Aermet 100 steel in the present study.

关键词： High-cycle fatigue Ultrahigh strength steel Inclusion S-N curve Fish-eye fracture

Third generation high strength low alloy steels with improved toughness

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Science China(Technological Sciences) 2012年第7期55卷 1797-1805页

作者： SUN XinJun LI ZhaoDong YONG QiLong YANG ZhiGang DONG Han weng yuqing Institute for Structural Materials Central Iron and Steel Research InstituteBeijing 100081China Department of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Chinese Society for Metals Beijing 100711China

On-line thermo mechanical controlled processing(TMCP) was conducted to develop the third generation high strength low alloy(HSLA) steel with high toughness *** ultra-low carbon content ensured a high level of upper shelf energy while ultrafine lath martensitic structure transformed from super-thin pancaked austenite during controlled rolling and *** reduction of martensite block size decreased ductile-to-brittle transition temperature(DBTT) and compensated the strength loss due to carbon ***,the excellent balance of strength and toughness values was obtained as 950-1060 MPa for yield strength,180 J for Charpy V-notch impact absorbed energy at 30℃,which is much superior to that of traditional martensitic *** mechanisms for the refinement of lath martensite block were proposed:One is the austenite grain refinement in the direction of thickness,and the other is the reduction in the fraction of sub-block boundaries with small misorientation and the increase in the fraction of block boundaries with large misorientation,possibly due to austenite hardening.

关键词： pancaked austenite lath martensite precipitate TMCP HSLA steel

Effects of Magnetic Annealing on Magnetic Properties in Nd_4Fe_(76)Co_3(Hf_(1-x)Ga_x)B_(16) Alloy

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Journal of Iron and Steel Research International 1999年第1期6卷 36-42页

作者： Gao Youhui Zhu Jinghan weng yuqing Eon Byung Park Choong Jin Yang Central Iron & Steel Research Institute Research Institute of Industrial Science and Technology

The best linear fit of Hc(T)/Ms(T) vs 2k1(T)/0Ms2(T) infers that Hc is determined by a nucleation process in nanocrystalline twophase magnet. The condition of the grain shapes is improved after adding Hf and Ga, but the surfaces are deteriorated by some precipitates on the boundary. Taking into account the values of , Neff, the results of TEM, and Moessbauer spectroscopy, the magnetic field heattreatment not only induces grain refinement but also causes a uniform distribution of the soft and hard phases. It is one recommendable method to improve the condition of the microstructure. Both the remanence and energy product values are increased by 20 %-30 % for all ribbons after annealing with magnetic field. The magnetic interaction in Nd2Fe14B/Fe3B+Fe based nanocrystalline twophase magnets is studied using M plots in this paper. It is found that the exchangecoupled interaction is greatly enhanced in the sample annealed with magnetic heattreatment, specially, Nd4Fe76Co3Hf0.5Ga0.5B16 which achieves the highest energy product (BH)max=126.4 kJ/m3.

关键词： magnetic annealing nanocrystalline heat treatment

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Ausforming effects on anisotropy of mechanical properties in HSLA martensitic steel

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Science China(Technological Sciences) 2012年第7期55卷 1806-1813页

作者： LI ZhaoDong SUN XinJun CAO WenQuan YONG QiLong YANG ZhiGang DONG Han weng yuqing Institute for Structural Materials Central Iron and Steel Research InstituteBeijing 100081China Department of Materials Science and Engineering Tsinghua UniversityBeijing 100084China The Chinese Society-for Metals Beijing 100711China

In order to clarify effects of prior pancaked austenitic structure on microstructure and mechanical properties of transformed martensite in ausformed steel,a super-thin pancaked austenite was processed by multi-pass rolling in a 0.03-2.6Mn0.06Nb-0.01Ti(wt%) low alloy *** evolution of prior pancaked austenite grain during multi-pass rolling was studied using Ni-30Fe model *** with the structure and texture in the prior super-thin pancaked austenite in Ni-30Fe alloy,the texture and anisotropy of mechanical properties of transformed martensite in the studied ausformed steel were focused *** were mainly three kinds of rolling texture components in the super-thin pancaked austenite:Goss {110} 001,copper {112} 111 and brass {110} *** were further transformed into the weak {001} 110 and strong {112} 110,{111} 112 texture components in the martensitic *** orientation relationship(OR) of lath martensite transformation from pancaked austenite in the ausformed steel deviated larger from the exact Kurdjumov-Sachs(K-S) OR than in the case of equiaxed austenite without *** tensile and yield strengths of the ausformed martensitic steel first decreased and then increased as the angle between tension direction and rolling direction *** main reason for the anisotropy of strength was considered as the texture component {112} 110 in ***,the anisotropy of impact toughness was more complex and the main reasons for it are unknown.

关键词： pancaked austenite lath martensite texture strength and toughness HSLA steel

Microstructures and mechanical properties of the third generation automobile steels fabricated by ART-annealing

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Science China(Technological Sciences) 2012年第7期55卷 1814-1822页

作者： CAO WenQuan WANG Chang WANG CunYu SHI Jie WANG MaoQiu DONG Han weng yuqing Central Iron&Steel Research Institute(CISRI) Beijing 100081China Chinese Society for Metals Beijing 100711China

The mechanical properties dependence on the microstructure was reviewed and analyzed,and the ultrafine grained duplex microstructure of BCC matrix and large fractioned austenite was given as one of the optimum structures to develop the third generation steel with high strength and high *** medium-Mn steels with different carbon contents processed by austenite reverted transformation(ART-annealing) were studied thoroughly to fabricate the ultrafine duplex steels with large fractioned *** lamellar typed ultrafine structure,the granular typed ultrafine duplex structure and the corresponding mechanical properties of the medium-Mn steels processed by ART-annealing were demonstrated in this *** was revealed that the duplex structure with large fraction of austenite and ultrafine grain structure is capable of producing steels with excellent combination of strength and ductility,i.e.,Rm A about 30-50 GPa%,which is about two times of that of the conventional automobile steels and close to that of the TWIP *** was concluded that the ART-annealing of the medium-Mn steels would be at least one of the promising ways to fabricate the third generation automobile steels in the near future.

关键词： automobile steel high strength and high ductility austenite reverted transformation(ART) m-Mn steel ultrafine grain size

The Value of γδ T Cells in Lung Infections and Advances in Diagnosis and Treatment

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Journal of Biosciences and Medicines 2024年第10期12卷 164-177页

作者： Jiyu Xiao Wei Wang yuqing weng Department of Respiratory and Critical Medicine Zhuhai Clinical Medical College of Jinan University (Zhuhai Peoples Hospital) Zhuhai China Department of Pulmonary and Critical Care Medicine Zhuhai Clinical Medical College of Jinan University (Zhuhai Peoples Hospital) Zhuhai China

Lung infections are usually caused by pathogenic microorganisms and are a disease with high morbidity and mortality. In clinical practice, the use of broad-spectrum antibiotics has become increasingly common, but this has also led to the problem of antibiotic abuse and irrational use, which in turn has spawned the emergence of multidrug-resistant bacteria, making the treatment of lung infections more complex and difficult. In the human immune system, γδ T cells play a crucial role in defense against foreign pathogens and regulation of autoimmune responses. These cells act as a bridge between innate and adaptive immunity and can be rapidly activated in the early stages of infection to produce inflammatory factors and chemokines that attract other immune cells to the site of infection. Recent advances have shown that γδ T cells not only play a direct role in the innate immunity of pathogen infection, but are also involved in regulating the subsequent adaptive immune response. The aim of this review is to explore the mechanism of γδ T cells in lung infections and to summarize the current progress of clinical research, with the aim of providing new scientific basis and therapeutic strategies for the treatment of lung infections.

关键词： Lung Infections γδ T Cells Immunotherapy IL-17

Achievements of New Generation Steel Project in China

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Achievements of New Generation Steel Project in China

进一步发展高炉喷煤和精料技术推动炼铁系统节能降耗和结构调整

海峡两岸第二届工程材料研讨会

作者： weng yuqing(The Chinese Society for Metals, Beijing, China)

Major achievements of the national project, Fundamental Research on New Generation of Iron and Steel Materials in China (NG Steel), are reviewed in the paper. Ultrafine grained steel technology, based on deformation induced ferrite transformation (DIFT)and successive microstructure changes, is illustrated for grain refinement in both plain low carbon steel and microalloyed steel. Delayed fracture resistance of alloy structure steel can be improved through prior austenite grain refinement. It is shown by results that nano scale precipitates play an important role to grain refinement in thin slab casting and rolling (TSCR)process. Progresses on super cleanliness, high homogeneity, welding and metallurgical process simulation are also briefly introduced.

关键词： NG steel high strength grain refinement DIFT delayed fracture

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钢铁 1998年第7期33卷 3-6页

作者：翁宇庆国家冶金工业局

回顾了１９９７年炼铁系统生产技术的进步以及炼铁系统面临的形势和任务，指出了炼铁技术发展的方向及炼铁技术发展的思路。

关键词：炼铁技术节能降耗结构调整

优化炼钢轧钢工艺结构,促进钢铁生产流程节能降耗,实现优质高效

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钢铁 1998年第6期33卷 3-6+47页

作者：翁宇庆国家冶金工业局

总结了１９９７年我国炼钢、轧钢生产的主要成绩和问题；提出了１９９８年冶金工业炼钢、轧钢行业发展的基本思路是继续坚持依靠科技进步加快企业产品、工艺、设备、生产组织经营的结构调整和优化作为中心任务，实现市场竟争力和经济效... 详细信息

总结了１９９７年我国炼钢、轧钢生产的主要成绩和问题；提出了１９９８年冶金工业炼钢、轧钢行业发展的基本思路是继续坚持依靠科技进步加快企业产品、工艺、设备、生产组织经营的结构调整和优化作为中心任务，实现市场竟争力和经济效益的同步提高。

关键词：结构调整节能降耗优质高效