低碳贝氏体钢的研究现状与发展前景

综述了低碳贝氏体钢的国内外研究现状,指出低碳贝氏体钢性能优良且成本低廉.并结合低碳贝氏体钢的市场需求和邯钢品种钢的研发方向,展望了低碳贝氏体钢的发展前景,提出低碳贝氏体钢产品品种的开发及其控轧控冷工艺的研制是其研究方向.     

Microstructure and Mechanical Properties of a Dissimilar Friction Stir Weld between Austenitic Stainless Steel and Low Carbon Steel

Dissimilar fusion welding of austenitic stainless steels to carbon steels has some metallurgical and technical problems.It was suggested that the solid-state nature of friction stir welding(FSW) can overcome these problems and produce a sound weld with reliable mechanical properties.In this study,plates of 304 stainless steel and st37 steel were welded together by FSW at tool rotational speed of 600 r/min and welding speed of 50 mm/min.In the stir zone(SZ) of 304 stainless steel,the results showed a refined grain structure with some features of metadynamic recrystallization.In the SZ of st37 steel,the hot deformation of material in the austenite region produced small austenite grains.These grains transformed to fine ferrite and pearlite by cooling the material after FSW.The production of fine grains increased the hardness and tensile strength in the SZ of both sides with respect to their base metals(BMs).     

碳钢和低合金钢模拟坑孔腐蚀试验方法研究

采用模拟坑孔腐蚀的闭塞电池法对其耐蚀性进行评价,选用两种典型的碳素船体钢及4种不同的坑孔溶液条件,并结合电化学极化和显微腐蚀形貌观察,对其闭塞电池试验方法进行了研究,结果表明,坑孔溶液为pH=4、质量浓度为3%的NaC l具有较好的模拟性与可操作性,闭塞电池试验结果与挂片结果有较好的对应性。     

Comparison of Impact Properties for Carbon and Low Alloy Steels

The impact properties of hot rolled carbon steel(used for the manufacture of reinforcement steel bars) and the quenched & tempered(Q&T) low alloy steel(used in the pressure vessel industry) were determined.The microstructure of the hot rolled carbon steel contained ferrite/pearlite phases,while that of the quenched and tempered low alloy steel contained bainite structure.Impact properties were determined for both steels by instrumented impact testing at temperatures between-150 and 200 C.The impact properties comprised total impact energy,ductile to brittle transition temperature,crack initiation and propagation energy,brittleness transition temperature and cleavage fracture stress.The Q&T low alloy steel displayed much higher resistance to ductile fracture at high test temperatures,while its resistance to brittle fracture at low test temperatures was a little higher than that of the hot rolled carbon steel.The results were discussed in relation to the difference in the chemical composition and microstructure for the two steels.     

Effect of High Pressure Heat Treatment on Microstructure and Compressive Properties of Low Carbon Steel

The effect of high pressure heat treatment on microstructure and compressive properties of low carbon steel were investigated by optical microscope,transmission...     

低、中碳钢材料高温化学抛光工艺

低、中碳钢材料低温化学抛光过程中双氧水易分解、温度不易控制、中温化学抛光配方中使用氢氟酸的废水中氟离子较难处理,为了解决这些问题研究了高温化学抛光液的组成和前处理工艺,分析了抛光液中各物质含量对工件产生的影响.结果表明,在不使用CrO3的情况下,将普通酸和常用助剂组合,温度控制在95～110℃时,可以使低、中碳钢工件表面抛光成镜面光亮,抛光时间短、速度快、效率高、容易控制、无有毒气体NOx逸出,废水中无有毒离子,可以实现清洁化生产.     

Characterization and Properties of Nanostructured Surface Layer in a Low Carbon Steel Subjected to Surface Mechnaical Attrition

A nanostructured surface layer was synthesized on a low carbon steel by using surface mechanical attrition (SMA) technique,The refined microstructure of the surface layer was characterized by means of different techniques, and the hardness variation along the depth was examined,Experimental results show that the microstructure is inhomogeneous along the depth ,In the region from top surface to about 40 μm depth,the grain size increases from about 100 nm to 1000 nm ,The grain refinement can be associated with the activity of dislocations After the SMA treatment, the hardness of the surface layer is enhanced significantly compared with that of the original sample ,which cam primarily be attributed to the grain refinement.     

合金元素对耐热钢组织及性能的影响

通过对ＨＫ４０、ＨＰ４５和ＺＧ４Ｃｒ２５Ｎｉ３５ＷＮｂ３种耐热钢高温力学性能的测试和各种状态下显微组织的观察分析，比较了其性能的优劣，并探讨了合金元素镍、钨及铌的作用。     

Solidification Structure of Low Carbon Steel Strips with Different Phosphorus Contents Produced by Strip Casting

In the present paper, low carbon steel strips with different phosphorus contents were produced using a twin roll strip casting process. The solidification structure was studied and its features were analyzed in detail. It was found that the strips possessed a fine microstructure compared with the mould cast steels. With increasing phosphorus content more ferrite has been formed with finer grains.     

钒、铬微合金化对高碳钢微观组织与力学性能的影响

为了开发性能更优的高碳盘条钢,在原有70钢的基础上,以铬、钒微合金化设计开发新钢种,并分析了铬、钒对试验钢的微观组织和力学性能的影响。铬、钒单独微合金化,使索氏体化率增大、片层间距减小、原始奥氏体晶粒细化;与70钢相比,随铬、钒含量的增加,钢的抗拉强度逐渐升高,断口伸长量下降。铬钒复合微合金化对钢中微观组织的改善明显好于单独微合金化;与70钢相比,铬钒复合微合金化钢的强度显著升高,塑性略有降低;与80钢相比,铬钒复合微合金化钢的强度和塑性均较高。     

Characterization and Properties of Nanostructured Surface Layer in a Low Carbon Steel Subjected to Surface Mechanical Attrition

A nanostructured surface layer was synthesized on a low carbon steel by using surface mechanical attrition (SMA)technique. The refined microstructure of the surface layer was characterized by means of different techniques,and the hardness variation along the depth was examined. Experimental results show that the microstructure is in homogeneous along the depth. In the region from top surface to about 40 /zm deep, the grain size increases fromabout 10 nm to 100 nm. In the adjacent region of about 40~80 /zm depth, the grain size increases from about 100nm to 1000 nm. The grain refinement can be associated with the activity of dislocations. After the SMA treatment,the hardness of the surface layer is enhanced significantly compared with that of the original sample, which canprimarily be attributed to the grain refinement.     

微合金元素Nb对低碳铸钢强度和冲击韧性的影响

采用中频炉冶炼制备不同Nb含量的微合金低碳铸钢,用光学显微镜(OM)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、液压万能强度试验机、半自动冲击试验机等手段研究了Nb微合金化对低碳铸钢显微组织、强度和冲击韧性的影响。结果表明,添加合适的微合金元素Nb可以使低碳铸钢的晶粒尺寸减小20.8%~34.6%,同时促进细小NbC析出相的形成,能有效提高低碳铸钢的强度和冲击韧性,晶粒细化和析出强化为其主要的强韧化机制。其中,含Nb量为0.044%的微合金铸钢屈服强度为350 MPa,抗拉强度为520 MPa,室温冲击功为119.7J。与普通低碳铸钢相比,其塑性基本保持不变,但屈服强度、抗拉强度和室温冲击功分别提高了20.7%、7.2%和25.6%。     

碳含量对Mo-W-Co合金组织与性能的影响

采用粉末冶金技术,在 Mo-W-Co 合金中添加不同质量分数的碳,研究碳含量对 Mo-W-Co 合金组织性能的影响。实验结果表明：碳含量对合金硬度的影响不大;在一定范围内,Mo-W-Co 合金的塑性随合金碳含量的增加呈先增后减趋势,碳含量为1%时合金塑性最好;在真空烧结过程中,碳和基体钼形成影响合金组织与性能的关键相 Mo2 C。     

Mechanical Properties and Temper Resistance of Deformation Induced Ferrite in a Low Carbon Steel

The microstructures and mechanical properties of deformation induced ferrite(DIF) in the low carbon steel Q235 under different deformation temperatures have been investigated systematically.Through deformation induced ferrite transformation(DIFT),ferrite grain can be refined to 3 μm and accounts for above 85% of the overall fraction.Yield strength of DIF(>500 MPa) is increased by up to 100% compared with the conventional low carbon steel.Comparison of microstructure and mechanical properties in the Q235 ste...     

Thermodynamic Research on Precipitates in Low Carbon Nb-Microalloyed Steels Produced by Compact Strip Production

Microalloying element Nb in low carbon steels produced by compact strip production （CSP） process plays an important role in inhibiting recrystallization, decreasing the transformation temperature and grain refinement.With decreasing the rolling temperature, dislocations can be pinned by carbonitrides and the strength is increased. Based on the two sublattice model, with metal atom sublattice and interstitial atom sublattice,a thermodynamic model for carbonitride was established to calculate the equilibrium between matrix and carbonitride. In the steel produced by CSP, the calculation results showed that the starting temperature of precipitation of Ti and Nb are 1340℃ and 1040℃, respectively. In the range of 890-950℃, Nb rapidly precipitated. And the maximum of the atomic fraction of Nb in carbonitride was about 0.68. The morphologies and energy spectrum of the precipitates showed that （NbTi） （CN） precipitated near the dislocations. The experiment results show that Nb rapidly precipitated when the temperature was lower than 970℃, and the atomic fraction of Nb in carbonitride was about 60%-80%. The calculation results are in agreement with the experiment data. Therefore the thermodynamic model can be a useful assistant tool in the research on the precipitates in the low carbon steels produced by CSP.     

Co、B对新型铁素体耐热钢组织和性能的影响

介绍了铁素体耐热钢的发展历程,综述了第四代耐热钢的国内外发展研究现状,重点介绍了Co和B元素对新型耐热钢组织性能的影响规律,指出优化合金元素含量提升新型耐热钢的蠕变性能和降低成本是未来发展方向。     

Cu对低合金钢耐海水腐蚀的影响

为研究Cu对低合金钢耐海水腐蚀性能的影响,选择含Cu低合金钢和碳钢各两种进行对比实验.利用室内间浸挂片、实海潮差区挂片和模拟闭塞腐蚀电池实验比较钢的耐全面腐蚀和点蚀能力;利用扫描电镜(SEM)、能谱分析(EDAX)、电子探针(EPMA)和X射线衍射(XRD)分析钢中夹杂物和锈层的特征.结果表明:Cu的添加不仅可提高钢的...     

Metallurgical and Corrosion Properties of Explosively Welded Ti6Al4V/Low Carbon Steel Clad

Titanium alloy (Ti6Al4V) and Iow carbon steel (LCS) were joined by explosive welding method using different ratios of explosive. Some metallurgical properties of joined samples were investigated. Joined samples were examined by means of optical microscope, scanning electron microscope (SEM) and tensile-shearing tests. Bending, tensile, hardness and corrosion behaviour of the samples were investigated. Separation was not occurred on the joining interface after tensile-shearing and bending tests. It is seen that hardness of both plates were increased with increasing explosive.It is found that increasing explosive ratio leads to an increase in corrosion. It is also found that corrosion rate was high at the beginning of the experiment but the rate of the corrosion decreased subsequently during the experiment.     

Metallurgical and Corrosion Properties of Explosively Welded Ti6A14V/Low Carbon Steel Clad

1.IntroductionIn order to join metals preserving their propertiesand to join metals having different properties,solid-statewelding methods are used[1].Explosive welding is a solid-state process in which controlled explosion forces to jointwo or more materials together under high pressures[2~5].It is used to joint directly a wide variety of similar or dis-similar metals that cannot be joined by any other weld-ing or bonding technique[6~8].The parameters of thesystem include:(1)the explosive cha…     

温轧温度对Cr-Ti-B系低碳钢组织与织构的影响

使用扫描电镜、电子背散射衍射、透射电子显微镜和固体内耗仪研究了温轧温度对Cr-Ti-B系低碳钢组织和织构的影响.结果 表明,温轧后钢的组织由变形铁素体和少量珠光体所组成,随着温轧温度的提高铁素体晶内剪切带的含量呈现先提高后降低的趋势,在450℃温轧剪切带的含量最高.剪切带的形成,与Ti和B元素的偏聚密切相关.在350℃...