汽车用弹簧扁钢60Si2Mn淬火开裂分析

对用60Si2Mn生产的汽车用弹簧扁钢出现的淬火裂纹形态及其形成原因进行了分析,研究结果表明：厚截面板簧选用60Si2Mn,由于此材质的产品淬透性稍差,采用水基淬火液淬火时,因冷却速度较快,需严格控制水基淬火液浓度,一旦控制不当易引起淬火开裂等现象。建议汽车板簧生产厂家选用50CrVA类淬透性较好的弹簧扁钢生产厚截面板簧,确保产品质量。     

60Si2Mn冶炼工艺技术分析

分析了６０Ｓｉ２Ｍｎ的冶炬工艺技术情况，对其存在的问题提出改进措施。     

Effect of Testing Temperature on Retained Austenite Stability of Cold Rolled CMnSi Steels Treated by Quenching and Partitioning Process

The effect of testing temperature on retained austenite (RA) stability of industrially cold rolled CMnSi sheet steel treated by quenching and partitioning (Q&P) process has been investigated by observing the deformation and transformation behavior of RA at different testing temperatures. Uniaxial tensile properties at different temperatures were determined and a correlation between RA stability and mechanical properties were also established. Ultimate tensile strength increases monotonously when temperature decreases, while total elongation reaches an optimum value between 0 and 20°C, where RA exhibits the greatest TRIP effect. Work hardening rate was calculated to decrease through three different stages in an oscillation manner, leading to significant enhancement in both strength and ductility. The kinetic of deformation‐induced martensite transformation is also studied and the stability of RA can be evaluated by comparing the kinetic parameter β.     

60Si2Mn连铸方坯的生产实践

石横特钢厂通过严格保证钢水质量，控制钢水及铸坯温度，拉坯速度和冷却强度，并采用浸入式水口保持浇注技术，在普通机上生产出合格的优质钢连铸坯，文章以６０Ｓｉ２Ｍｎ合金弹簧钢为重点，阐述了生产符合标准要求的优质钢连铸方坯的电炉冶金及Ｒ５．２５ｍ罗可普型小方坯铸机的生产工艺参数。     

江西长力转炉开发60Si2Mn弹簧钢工艺研制

介绍了江西长力转炉研发60Si2Mn弹簧扁钢的过程,以及60Si2Mn弹簧钢的转炉生产工艺及研制结果.     

淬火-配分马氏体钢的组织特征

淬火-配分(Quenching and Partitioning,简称QP)工艺是针对马氏体钢提出的热处理新工艺。利用QP工艺处理40Si2Ni2钢,并通过扫描电镜观察其微观组织特征。结果表明,与传统淬火+回火工艺得到的组织不同,QP组织为低碳(回火态)和高碳马氏体(淬火态)共存,其中高碳马氏体呈现为有规则几何形状、边界清晰、无析出物析出的块状组织,淬火温度(QT)对高碳马氏体(淬火态)量有影响。     

Microstructure and Wear Resistance in Medium and High C Steels Treated by Quenching and Partitioning

The quenching and partitioning (Q&P) steels have shown to be promising candidates to be applied in fields where wear resistance is required. In this study, a medium and a high C steel are heat treated by Q&P and the resulting microstructure, hardness, and wear resistance are characterized. The mechanical stability of the austenite phase under wear test conditions is investigated. It is found that the stability of austenite is very high in the high C steel and decreases in the medium C steel. Additionally, the hardness and wear behavior of the Q&P-treated steels are compared with the results obtained for quenching and tempering (Q&T) treated samples, showing that, although the hardness of Q&P steels is quite lower, the obtained wear rates are similar. It means that in the studied Q&P steels, although the austenite transformation into martensite does not occur considerably, the presence of austenite might play a key role in the wear resistance.     

60Si2Mn钢渗扩氮冷待淬火强韧化研究

研究了淬火加热温度，渗扩氮冷待淬火对６０Ｓｉ２Ｍｎ钢的显微组织、硬度和亚结构的影响；对６０Ｓｉ２Ｍｎ钢制六角螺母冲头进行了寿命试验，采用模拟理想冷却曲线设计的方便易行、节能省时的渗扩氮冷待淬火强韧化热处理，冲头的使用寿命可提高２倍以上。     

昆钢60Si2Mn弹簧钢冶炼实践

以昆钢炼钢厂开发60Si2Mn弹簧钢为实例,介绍了60Si2Mn弹簧钢冶炼的工艺流程：（KR）铁水脱硫预处理—50t氧气顶底复吹转炉-LF精炼。通过对LF精炼造弱碱性渣控制钢中夹杂物,KR法铁水预处理采用底吹氮气达到更好的处理效果等方法,对60Si2Mn弹簧钢冶炼过程中夹杂物、碳、磷、硫的控制进行了分析。     

60Si2Mn弹簧钢半固态浆料的制备研究

研究了60Si2Mn弹簧钢半固态浆料的制备规律，结果表明：在本实验条件下，当搅拌时间为2min时，可以获得尺寸大小为100-300μm、固相率为40％～50％的球状初生奥氏体的半固态浆料，这样的半固态浆料便于从搅拌室底孔中放出；电磁搅拌使60Si2Mn弹簧钢熔体获得均匀的温度场和溶质场，抑制了发达的初生奥氏体枝晶的形成，为球状晶的获得奠定了基础；电磁搅拌引起蔷薇状初生奥氏体枝晶出现强烈的温度起伏和枝晶臂根部熔断是获得球状晶粒最重要的原因。     

60Si2Mn半固态非枝晶组织特征与触变性能

利用自制高熔点半固态试样制备装置,对60Si₂Mn半固态试样非枝晶组织以及影响因素进行了试验研究.结果表明:60Si₂Mn半固态显微组织结构的特点为近球形先析出相均匀分布于残余液相.搅拌工艺制度、搅拌功率与搅拌时间对凝固初生相形态影响显著.采取降温搅拌方式,较大搅拌功率和搅拌时间,初生组织得到了充分的细化和均匀的球化.60Si₂Mn非枝晶组织形态是影响剪切变稀触变性能的主要因素.     

60Si2Mn钢动态再结晶数学模型的实验研究

利用计算机技术对轧制过程进行组织性能预报在工业生产中有着广泛的应用前景，而开发合理的数学模型就成为组织性能预报的关键：轧制过程中发生的动态再结晶行为直接影响着预报结果的可靠性。作者在实验室条件下采用单、双道次压缩实验对60Si2Mn钢的轧制过程进行了研究，得到了该钢种动态再结晶的计算模型：     

Stress-Strain Partitioning Analysis in Dual Phase Steels

Dual-Phase (DP) steels are made of ductile ferrite phase and hard martensite phase.Although it became crucial in progress of automotive industry to save fuel consumption and reduce total weight of vehicles,we need more accurate estimation of distribution to mechanical properties in total amounts of specimen.DP steels have considerable difference of mechanical levels in each phase including ferrite and martensite.That is why this study focuses on deconvolution of experimental tensile curve into ferrite and martensite using EBSD for calculation of phase volume fractions and Swift equation.Nanoindentation for certain parameter of each phase was conducted to produce the deconvolution curves.     

60Si2Mn弹簧钢中Si,Ni,Cu的测定及溶样方法改进

在同一溶样体系条件下,对60Si2Mn弹簧钢中硅、镍、铜元素进行了测定,获得较满意的结果.     

60Si2Mn弹簧扁钢崩料分析与改进研究

针对江西长力汽车簧股份有限公司轧制厂60Si2Mn弹簧扁钢生产中的崩料问题,进行了现场调研和试验研究分析,指出钢中氧、氮含量高,成分偏析,扁钢韧性下降是崩料产生的主要原因,并指出了改进措施,通过实施跟踪证明,取得了满意的效果。     

On the role of Manganese Partitioning in Metastable Austenite by Quenching and Partitioning Treatment

With the aim to study the role of “frozen” concentration gradient of manganese (Mn) element in stability of retained austenite (RA) with multiple-stage martensite transformation, a series of intercritical annealing (IA) temperatures is conducted before quenching and partitioning (Q&P) treatment. Morphology and distribution of RA are observed by field emission gun scanning electron microscope and electron back-scatter diffraction. The volume fraction (7%–16%) and stability of metastable RA is found to be affected profoundly by IA temperature. Thermodynamic and kinetic analysis are conducted to elucidate the evolution of RA in process of IAQP treatment. The predicted levels of RA are in good accordance with measurements. It is found that the inhomogeneous partitioning of Mn in period of IA, combining with the incomplete partitioning of carbon during Q&P, radically regulated the Q&P microstructure. The incomplete partitioning of carbon in RA, with excess carbon segregation at dislocations and boundaries, lead to partition-less bainite transformation owing to the average carbon content in RA lower than the “T_o” threshold.     

弹簧扣件用60Si2Mn热轧盘条的开发及应用

介绍了安钢60Si2Mn热轧盘条的工艺特点、产品质量,及其在铁路弹簧扣件生产中的应用。冶炼工艺采取了多项关键技术以实现窄成分控制和钢水洁净度控制,保证了铸坯无缺陷生产;利用摩根第六代高速线材生产工艺设备,采用控轧控冷,盘条尺寸精确控制在13～13.2mm,抗拉强度为950～1050MPa,面缩为36%～47%,硬度为269～288HRB,组织为S+P+F,脱碳层深度小于1%D;生产的60Si2Mn弹条硬度为41～46HRC,组织为均匀回火索氏体,疲劳试验达到700万次无损坏,残余变形小于1mm,完全满足TB/T 1495.2和用户要求。     

氧气转炉熔炼的60Si2Mn扁弹簧钢的内部质量分析

对采用氧气转炉熔炼＋ＬＦ炉精炼｜＋连铸连轧工艺生产的６０Ｓｉ２Ｍｎ扁弹簧钢的化学成分，金相组织以及经８７０℃油淬＋５００℃水冷处理扣的力学性能进行测试，证明其内部质量良好，各项性能优良，同时指出，为完善连铸坯内部质量，Ｃ和Ｓｉ的含量分别在０．５６≤Ｃ≤０．６０％，１．５０≤Ｓｉ≤１．８０％，应控制Ｃ含量的波动在±０．０２％内。     

两种不同冶金工艺生产的60Si2CrVA弹簧钢的高周疲劳性能

 采用旋转弯曲疲劳试验研究了两种不同冶金工艺生产的60Si2CrVA弹簧钢的高周疲劳破坏行为。结果表明,尽管两种试验料的氧含量接近,但两者夹杂物特征的差异使其疲劳性能存在明显的差异。与采用电炉+LF+VD+CC工艺生产的X8料相比,采用转炉＋LF+RH+CC工艺生产的X6料中的夹杂物数量明显减少,夹杂物尺寸较小,同时还减少了不规则的多棱角富Al2O3夹杂,因而后者的疲劳强度得到明显提高,并具有良好的疲劳寿命稳定性。     

Quenching and Partitioning of CMnSi Steels Containing Elevated Manganese Levels

Quenching and partitioning (Q&P) is receiving increased attention as a potential processing route to develop “Third Generation” advanced high strength steel (AHSS) properties. The Q&P process consists of quenching a steel from a reheat temperature to a pre‐determined temperature in the M_s ? M_f temperature region followed by a so‐called partitioning treatment at the quench temperature or higher. The present contribution investigates the Q&P response of laboratory‐processed CMnSi alloys with 3 or 5 wt% manganese. Samples were processed at quench temperatures between 70 and 250°C with partitioning temperatures of 400 and 450°C for times up to 100 s. Scanning electron microscopy and X‐ray diffraction were utilized to evaluate the Q&P microstructures. Attractive properties were generated with tensile strength/total elongation combinations such as 1500 MPa and 17%.