冷轧压下率对 ELC-BH 钢板织构的影响

通过极图分析方法研究了冷轧压下率（８０％～９０％）对Ｎｂ＋Ｔｉ处理的ＥＬＣ－ＢＨ钢板冷轧和退火织构的影响．结果表明,冷轧和退火织构的基本特性与冷轧压下率无关,冷轧压下率增大对于退火织构的有利组分与不利组分的强度比影响不大．     

拉伸变形对AA6016铝合金汽车外板再结晶组织及性能的影响

为优化冲压成形工艺,研究了不同拉伸形变量对T4P态AA6016冷轧薄板再结晶、析出行为、烘烤硬化性及断裂方式的影响规律.采用与气垫炉生产线类似的新型热处理设备,对合金进行固溶处理,预时效后室温停放,获得T4P态合金.以单向拉伸模拟板材局部冲压成形过程,采用金相显微镜、扫描电镜和透射电镜,对合金再结晶组织、拉伸断口以及位错进行观察,并结合DSC测定和拉伸性能测定,对合金析出行为及力学性能表征.结果表明:随拉伸形变量增加,局部晶粒有被拉长的趋势;形变可抑制GP区溶解,并促进强化相析出;烘烤硬化性随形变增加而减弱;形变较小时,烘烤前后断裂方式均为塑性断裂,而形变较大时,烘烤前合金更加趋向于解理断裂,烘烤后解理断裂趋势减弱.     

Deformation behavior of ultra-low carbon steel in ferrite region during warm processing

The hot deformation experiments of ultra-low carbon steel in ferrite range were carried out in a hot simulator in order to research hot deformation behaviors of ultra-low carbon steel in ferrite range at low temperature. The results show that the influences of deformation parameters on flow stress are different to those in austenitic deformation. The deformation characteristic parameters were calculated for ultra-low carbon steel in ferrite region. The flow stress equation for ultra-low carbon steel in ferritic deformation at low temperature was obtained.     

PEPSET和呋喃树脂自硬砂工艺性能对比研究

目的　研究铸铝件用ＰＥＰＳＥＴ 树脂自硬砂和呋喃树脂自硬砂的工艺性能． 方法　对比两种造型制芯材料常温性能和高温性能的实验研究方法． 结果　通过实验获得两种树脂自硬砂的工艺参数, 并就两种自硬砂的硬化速度、硬透性、发气性等的实验结果曲线进行对比分析． 结论　ＰＥＰＳＥＴ 树脂自硬砂工艺性能良好, 可望成为树脂自硬砂工艺的一个重要的发展方向．     

A creep technique for monitoring the aging precipitation in Cu-Nb bainitic steels

A creep technique was applied on a Gleeble-1500 thermal simulator for monitoring the aging precipitation in ultra-low carbon steels containing various coppers. The aging hardening curve was obtained by the hardness testing. With the aid of an optical microscope and TEM, the microstructure and the aging precipitates were detected. The results indicate that when the precipitation occurs during the creep a plateau will appear on the creep curve; the left-hand and right-hand endings of the plateau correspond to the precipitation start （Ps） and finish （Pf） times, respectively. The Pf obtained from the creep curve coincides with the peak hardness time （tp） at the aging hardening curve. A precipitation-time-temperature （PTT） diagram of the steel can be obtained.     

自硬砂替代油砂制芯工艺可行性分析

目的研究用ＰＥＰＳＥＴ自硬砂法替代油砂制芯工艺的可行性．方法通过实验,从ＰＥＰＳＥＴ自硬砂与油砂的硬化特性、抗拉强度、发气性、溃散性以及经济性等方面进行了对比分析．结果ＰＥＰＳＥＴ自硬砂各种工艺性能都优于油砂,可替代油砂制芯．结论ＰＥＰＳＥＴ自硬砂制芯工艺简单,可明显提高铸件质量,节约能源,降低成本,具有推广和使用价值．     

Hot deformation behavior of a Cr-containing low carbon steel in the ferrite range

A low carbon steel with Cr addition of 0.46wt% combined with trace elements of Mn and Ti was studied.The apparent activation energy of deformation and the hot deformation equation of the steel in the ferritic range were determined by means of single hot compression tests.The hot-rolled strip of 3 mm in thickness rolled in the ferritic range was obtained using a laboratory hot rolling mill.The mechanical properties show that the values of yield strength and ultimate tensile strength are 230 and 330 MPa,respe...     

High performance low cost steels with ultrafine grained and multi-phased microstructure

Ultrafine grained ferrite was obtained through tempering cold rolled martensite with an average grain size of 200―400 nm in a low carbon and a microalloyed steel. Thermal and mechanical stability of the two steels was studied. Due to the pinning effect of microalloyed precipitates on the movement of dislocations and grain boundaries, the recrystallization and grain growth rate were retarded, and the thermal stability of ultrafine grained microstructure was improved. The ultrafine grained ferritic steel was ...     

Effect of Strain Rate on Formability in Sheet Metal Forming

ＥｆｆｅｃｔｏｆＳｔｒａｉｎＲａｔｅｏｎＦｏｒｍａｂｉｌｉｔｙｉｎＳｈｅｅｔＭｅｔａｌＦｏｒｍｉｎｇＬＩＣｈｕｆｆｉｎｇ；ＬＩＸｕｅｃｈｕｎ；ＹＡＮＧＹｕｙｉｎｇ；ＬＩＳｈｕｏｂｅｎ（李春峰），（李雪春），（杨玉英），（李硕本）（Ｄｅｐｔ．ｏｆＭａｔ...     

锈蚀冷弯薄壁型钢板材力学性能退化规律

为了研究锈蚀对冷弯薄壁型钢和热轧钢材料力学性能的不同影响,通过对工业环境下服役多年的冷弯薄壁C型钢进行拉伸试验,借助3Dscan手持式激光扫描仪得到腐蚀钢板表面形貌,探讨了锈蚀程度对其材料力学性能的影响。将试验结果与锈蚀热轧钢进行对比分析,比较了锈蚀对两种钢材表面形貌、断口形式、应力-应变曲线、力学性能指标的不同影响。研究结果表明:锈蚀冷弯薄壁型钢三维粗糙度参数S_a、S_q随锈蚀率的增大而呈现逐渐增大趋势,且增长速率高于热轧钢;锈蚀冷弯薄壁型钢的弹性模量、屈服强度、极限强度和极限应变均随着锈蚀率的增大呈线性下降,但伸长率随锈蚀率的增大呈二次曲线下降;同等锈损深度下,冷弯薄壁型钢的弹性模量、屈服强度、极限强度、极限应变和伸长率的下降速率均大于热轧钢,证明了锈蚀对冷弯薄壁型钢力学性能的影响高于热轧钢。     

Bake hardening behavior of TRIP and DP steels

The bake hardening (BH) behavior of transformation-induced plasticity (TRIP) and dual-phase (DP) steels after different prestrains was studied. The experimental results indicate that TRIP steel exhibits good BH ability while DP steel does not, and pre-strain displays a strong effect on the BH values of both steels. The comparison of microstructures of the two steels showed that the hard second phase in the matrix might be harmful to the BH ability. For deformed specimens, baking resulted in a loss of uniform elongation, but there was no obvious decrease in uniform elongation for unprestrained specimens.     

BN对超低碳钢连铸保护渣性能的影响

采用C BN作为骨架粒子,研究开发了一种新型的超低碳钢保护渣.其性能可以满足超低碳钢连铸的需要.C BN作为骨架粒子可以使保护渣的粘度减小、熔化温度降低、熔化速度降低、结晶温度降低.     

针状硅灰石对磷酸盐骨水泥性能的影响

以磷酸氢二钾和磷酸二氢钾为固化液,以磷酸四钙、α-磷酸三钙、磷酸氢钙、焦磷酸钙、羟基磷灰石和碳酸钙为原料合成骨水泥,向其添加针状硅灰石,研究了针状硅灰石对其性能的影响。结果表明,在磷酸钙骨水泥中添加针状硅灰石可以缩短凝结时间,提高抗压强度。当针状硅灰石的添加量为3%,骨水泥性能达到最佳;其初凝时间、终凝时间分别为14和28 min,样品在Ringer’s模拟液溶液中浸泡2周后抗压强度达49.23 MPa,浸泡液的pH值变化幅度小(7.1~7.8),在安全范围之内。     

CSP工艺条件下低碳钢板带材力学性能研究

热轧板带材成品因其内在组织形态及成分不同而呈现较明显的力学性能差异.就包钢薄板坯连续连轧CSP工艺条件下,低碳典型钢种Q235B和SS400显微组织及轧制工艺对材料力学性能的影响进行了实验研究.用数理统计方法建立了工艺参数与产品性能回归数值模型,模型拟合效果较好.     

软煤应变强度硬化冲击灾变

煤与瓦斯突出软煤层不具冲击倾向性,但在深部开采中却发生了软煤层冲击灾变动力现象.为探索软煤冲击灾变的成因,通过文献研究和工程案例实证分析,证明了软煤层冲击灾变现象的客观存在;通过煤样无侧限单轴压缩试验和冲击倾向性测定,得知试验煤样无冲击倾向性,极限载荷后单调应变强度软化;模拟工程背景现场与掘进工作面和采煤工作面中部相同的边界约束和加载条件,开展单自由度边界承压试验,考察灾变全程应力、应变、声发射特征,研究软煤冲击灾变机理.结果表明:单自由度边界条件下加载,3个煤样均出现应变强度软化-硬化-灾变过程,甚至反复软化-硬化;经应变强度硬化,灾变前煤样抗压强度均超过冲击倾向性的阈值条件;定义了应变强度软化、应变强度硬化系数,灾变前应变强度硬化系数分别为1. 26,1. 53,2. 25,应变强度硬化程度比较显著;软煤在单自由度约束条件下承压,应变硬化达到煤样冲击破坏强度条件时,可发生类似硬煤的冲击灾变,合理解释了现场软煤层冲击灾变的成因.深部高应力条件下,煤与瓦斯突出软煤掘进和开采,要对应变强度硬化导致煤层冲击灾变引起重视;工程上,这种冲击灾变的强度一般不高,但其可诱导煤与瓦斯突出或瓦斯异常涌出,危害性很高.     

冷轧超低碳钢带表面缺陷的研究与分析

针对马钢CSP工艺生产的某品种冷轧超低碳钢带表面缺陷进行了详细的统计和分析,同时对现场收集到的典型缺陷试样进行金相和扫描电镜分析,找出了钢带表面缺陷的种类、来源及分布的变化规律。对冷轧超低碳钢带表面缺陷分析发现缺陷主要是由具有结晶器保护渣特征的钙铝酸盐夹杂物、钙铝酸盐和硫化钙共生的夹杂物以及表面条状的氧化铁皮压入造成。本文根据表面缺陷分析研究的结果提出了相应的工艺控制措施,降低了表面缺陷的发生率。     

利用人工神经网络模型预测Q235B热轧板带力学性能

从某公司的薄板热轧管理机中随机抽取数据,用人工神经网络中的BP网络建立原始化学成分和热轧生产的主要工艺参数与产品力学性能之间的关系,来预测产品的力学性能.离线仿真表明,产品力学性能的预报值与实测值的相对误差很小.抗拉强度预报值与实测值的相对误差有88%不超过±2%,屈服强度预报值与实测值的相对误差有86%不超过±4%,延伸率预报值与实测值的相对误差有78%不超过±6%.     

Toughening mechanisms of a high-strength acicular ferrite steel heavy plate

An ultra-low carbon acicular ferrite steel heavy plate was obtained with an advanced thermo-mechanical control process-relaxed precipitation controlled transformation (TMCP-RPC) at Xiangtan Steel, Valin Group. The heavy plate has a tensile strength of approximately 600 MPa with a lower yield ratio. The impact toughness of the heavy plate achieves 280 J at ?40°C. The fine-grained mixed microstructures of the heavy plate mainly consist of acicular ferrite, granular bainite, and polygonal ferrite. The high str...     

成核剂和填料对反式-1,4-聚异戊二烯性能的影响

研究了成核剂(PL285)和各种填料对反式-1,4-聚异戊二烯(TPI)力学性能和硬化速度的影响。研究发现,加入成核剂后,TPI各项物理性能增加,且随成核剂用量的增加屈服强度和拉伸强度增大,弯曲模量、弯曲强度和邵尔D型硬度降低。加入填料后TPI的拉伸强度和断裂伸长率降低,屈服强度、弯曲强度、弯曲模量、邵尔D型硬度及100%定伸应力增大;其中填充白炭黑的TPI各项物理性能最佳。填料使TPI硬化速度降低,几种填料中填充白炭黑的TPI硬化速度最快,且用量增加硬化速度降低。     

Effect of gear teeth finishing method on properties of teeth surface layer and its resistance to pitting wear creation

This work presented the characteristics of two gear teeth finishing methods, due to the properties of gear teeth surface layer obtained at the tooth working depth. These methods are: 1) the teeth carburization, hardening to a hardness of HRC 60-62 and then grinding, 2) the soft gear shaving as the final mechanical treatment and then carburizing and hardening to the hardness of HRC60-62. This work included the test results of the contact fatigue strength carried out on the circulating power system. The Wohler curves were plotted due to the obtained results, as the basis for the practical evaluation of the considered gear finishing methods. The parameters like volume distribution of the voids, content of the retained austenite, compressive residual stress value, but also the results of contact fatigue strength tests, are more favorable for the teeth shaving method than for the teeth grinding method.