高强度大梁钢纵剪后镰刀弯成因及处置

国内某商用车制造厂频繁发生高强度大梁钢开平板纵剪后的条料出现镰刀弯大于标准要求7 mm 的问题。通过对热轧生产线、开平机组和剪板机等工序进行排查,确认镰刀弯主要在开平机组产生。通过对开平机组粗矫直机、精矫直机分别单独投入使用,确认镰刀弯主要由于精矫直机调校不良诱发,最终通过调整精矫直机矫直辊插入量、出入口倾斜、传动侧与操作侧倾斜,消除了镰刀弯缺陷。     

TiN粒子在焊接热循环过程中的溶解、粗化及再析出行为

采用萃取复型技术,对经受焊接热循环不同阶段的试样进行研究,分析TiN粒子在焊接热循环不同阶段的溶解、粗化及再析出行为。结果表明,在焊接热循环加热过程的低温阶段（1200℃以下）,粒子的溶解以粒子的尺寸减小为主要特征,粒子数量变化不大。在焊接热循环加热过程的高温阶段（1200-1350℃）,大量小尺寸粒子消失,粒子平均尺寸显著增大。研究发现,TiN粒子的溶解存在很大的滞后效应,在冷却过程的高温阶段（1350-1300℃）,粒子仍继续溶解,在冷却过程的低温阶段（1300℃以下）,固溶状态的Ti与N结合并沉淀到残留的TiN粒子上,使粒子粗化。在焊接热循环过程中,Ti微合金钢原始奥氏体晶粒长大主要发生在冷却阶段。     

铝钪中间合金的制备方法

本文系统地介绍了目前制取铝钪中间合金的几种方法,对对掺法、熔盐电解法及金属热还原法的优缺点进行了比较,指出作者新近实验成功的氯化钪铝镁热还原法为制备钪中间合金提供了有广阔发展前景的途径。     

钢中稀土微合金化作用与应用前景

低氧硫钢中室温下稀土固溶量达10-5～10-4,MnS夹杂完全变质后,稀土固溶量显著增加,酸溶铝,Nb,Ti均有利于提高钢中稀土固溶量.固溶稀土偏聚在晶界,减少硫、磷在晶界的偏析,渗碳体中固溶稀土多于铁素体.稀土和碳相互作用,减少珠光体数量、珠光体片间距和渗碳体厚度,细化珠光体组织,提高硬度.稀土对钢的强度影响具有两面性,稀土能提高锰碳钢的屈强比和有利于改善低合金高强度钢的强韧性.稀土在低合金高强度钢中有广泛的应用前景,发展具有中国资源优势的稀土微合金钢有重要的意义.     

高砷次氧化锌综合回收试验研究

介绍了硫酸焙烧法处理高砷次氧化锌的试验研究,主要探讨了焙烧的温度,时间及硫酸用量对有害元素砷,氟、氯等脱除率的影响,工业试验证明,铅,锌,锗的直收率分别为99％,98％,60％以上,砷的脱除大于90％,氟、氯的挥发率大于95％。     

22SiMn2TiB钢淬火与回火过程中的组织演变

以超高强度钢 22SiMn2TiB 为对象,研究了在淬火、回火和配分状态下组织的演变规律.采用光学金相显微镜(OM)、扫描电镜(SEM)和 X 射线衍射技术(XRD)研究了不同处理状态下组织的演变规律.实验表明,回火或配分温度低于 320 ℃,板条马氏体组织形貌没有明显变化,且不随回火和配分时间的变化而变化;在此温度以上进行配分,不论配分时间的长短,组织皆转变为回火组织.表明 320 ℃为该钢材的临界回火、配分温度.随着回火温度的升高,位错密度下降;且 320 ℃以下温度回火或配分,马氏体衍射峰的半峰宽 FWHM 只是略有减少,表明虽然板条马氏体的组织形貌没有明显变化,但板条内的位错密度和内应力降低.     

18CrNiMo7-6���ִָ�״��֯���Ƽ������ѧ���ܵ�Ӱ��

Effect of normalized cooling treatment on banded structure of gear steel 18CrNiMo7-6 was analyzed through metallographic microscope. Effects of banded structures with different degree on micro hardness uniformity, composition segregation, mechanical properties of test steels after quenching and tempering were analyzed through microhardness tester, scanning electron microscope, tensile testing machine, impact testing machine and metallographic microscope. The results show that, banded structure can be reduced to 1.5 degree after austenizing heat preservation at 930??, Strong wind cooling to 610??, furnace cooling to 400?? and then air cooling. But continuous rapid cooling can result in the formation of a large amount of bainite; Micro hardness range of test steels with different banded structure degree is between 30~35 HB after quenching at 850?? and tempering at 180??. Hardness uniformity and anisotropy of mechanical properties are comparable.     

Distribution law of flow field and temperature field in electroslag remelting withdrawal process

A three- dimensional mathematical model was developed to describe the interaction of multiple physical fields during the electroslag remelting withdrawal (ESRW) process. Flow fields and temperature fields of the ESRW system were simulated by commercial software ANSYS. The flow fields, temperature fields and the shapes of the molten pool during the ESRW process with different electrode immersed depths and slag heights were analyzed and compared. The temperature of ingot surface was measured, and the accuracy of simulation results was verified. The results show that there are two pairs of vortexes in slag bath during the ESRW process. A pair of large vortexes turns counterclockwise, and another pair of small vortexes rotates clockwise. The speed of slag increases with the increasing of immersion depths of the electrode, and decreases with the increasing of slag heights. There are two high temperature zones in the slag bath, and the temperature in the slag bath is higher than that in the metal bath. The temperature of ESRW system (electrode, slag bath and ingot) becomes higher with the increasing of immersion depths of the electrode, whereas becomes lower with increasing of slag heights.     

Effect of process parameters on microstructure and mechanical properties of non- annealed cold heading steel SWRCH35KM

In order to realize the on- line softening treatment of non- annealed cold heading steel SWRCH35KM, the influence of controlled rolling and controlled cooling process on the microstructure and mechanical properties of medium carbon cold heading steel was investigated. The results show that the microstructures of spherular pearlite dispersed in 60%-63% ferrite matrix are obtained after step slow cooling process. With the decrease of finish rolling temperature from 850?? to 750??, ferrite grain size refines from 15-16. 9??m to about 10??m, and spheroidization of pearlite tends to significantly. Tensile strength of test steel with step slow cooling process is about 490-510MPa, elongation is 36. 5%-40. 5%, and hardness is 73HRB-78HRB. Compared with the air cooling process, the tensile strength of test steel decreases by about 30-40MPa, elongation increases by 1%-3% and hardness decreases by about 2HRB-3HRB.     

Creep and microstructure evolution of foreign and domestic 10Cr rotor steel

In order to understand the property features of domestic 10Cr steel used for turbine rotor in ultra- supercritical unit, the research was conducted on domestic and foreign 10Cr steel for comparison. Firstly, the development of rotor steel and research situation of foreign and domestic 10Cr steel were introduced. The creep and microstructure evolution was studied on foreign and domestic 10Cr rotor steel for comparison. The results indicate that creep rupture strength at 595?? of the foreign 10Cr steel is higher than that of domestic 10Cr steel. The foreign and domestic 10Cr rotor steels have similar microstructure evolution features. With increasing time, different phases including M23C6?? MX?? Laves propagate, accumulate and grow subsequently. The Nb- rich phase with large size is found in domestic 10Cr steel and thought to have negative influence on properties.