大型支撑辊的堆焊修复工艺及应用

大型支撑辊重量大、辊径大、辊面长、耐磨层厚,采用传统的堆焊工艺修复Cr3~Cr5大型支撑辊难度大,母体金属与堆焊层容易在堆焊时发生相变,导致开裂。另外,传统的轧辊堆焊修复工艺不合理,修复的轧辊力学性能较差,限制了轧辊的使用寿命,大量报废的轧辊尤其是大型轧辊长期堆积在轧钢厂内,增加了生产成本,造成了极大浪费。为此,开展了大型热轧Cr3~Cr5支撑辊及大型冷轧Cr3支撑辊焊材制备、堆焊工艺及修复技术研究。技术实施表明,修复后的支撑辊使用寿命达到新轧辊的寿命,每支堆焊修复支撑辊上机使用至报废尺寸,至少可循环堆焊修复3次,使支撑辊单项辊耗成本在每个循环周期内降低40%~60%,同时解决了大型支撑辊焊接性能不稳定的难题。     

冷轧支承辊堆焊技术研究进展

分析了国内外冶金轧辊堆焊修复技术的发展状况,并对国内外轧辊堆焊技术进行了比较,着重对冷轧支承辊堆焊材料进行了较为全面的概括,指出现行冷轧支承辊堆焊材料存在的问题,对冷轧支承辊堆焊修复工艺进行了介绍,最后对国内冷轧支承辊堆焊修复进行展望.     

中厚板大型锻钢支撑辊堆焊修复实践

与有关大型设备修造厂合作,通过选用合理的堆焊材料及堆焊工艺,成功地对安钢2800mm中厚板机组失效的支撑辊进行了堆焊修复再利用,从而延长了支撑辊的使用寿命,降低了轧辊消耗,为企业可持续发展开辟了一条新途径.     

窄带不锈钢冷轧支承辊堆焊修复技术

依据窄带不锈钢冷轧支承辊使用工况,选择了YJ012-S堆焊过渡层和YJ243-S药芯焊丝作为堆焊工作层并辅以焊前预热和焊后回火热处理的自动埋弧堆焊工艺对冷轧支承辊进行堆焊修复.堆焊修复后的冷轧支承辊,其强韧性和耐磨性优于原9Cr2Mo辊面金属.修复后的冷轧支承辊在实际生产线上进行运行考核,相对原辊,寿命提高了1倍,满足了冷轧支承辊的使用要求.     

钢管冷轧辊等离子弧粉末堆焊工艺

本文在充分地研究钢管冷轧辊的技术条件和市售的等离子弧堆焊粉末性质的基础上,更换了目前冷轧辊的基体材料,研制了适合堆焊钢管冷轧辊曲面型工作面的小型等离子弧粉末焊枪,选出了合适的合金粉末,确定了最佳工艺参数,并拟定了防止堆焊层裂纹的工艺措施,为钢管冷轧辊延长使用寿命、降低成本、修复旧轧辊开辟了一个新的途径。     

热连轧精轧机Cr4支承辊堆焊修复再制造技术

通过对鞍钢1700精轧机Cr4支承辊母材成分和力学性能进行分析,采用自主开发的耐磨堆焊材料,并配以先进的全数字焊接设备及科学的修复工艺,成功地实现了精轧机Cr4支承辊的堆焊修复再制造。同时,通过实际应用验证,经堆焊修复的精轧机Cr4支承辊完全符合轧制工艺要求,并且其毫米过钢量达到新品轧辊水平,而修复费用仅为新品轧辊的50%。     

冷轧辊耐磨堆焊修复工艺

从轧辊局部堆焊修复入手,介绍了Cr3型冷轧工作辊耐磨堆焊参数及试验过程,进行了堆焊层耐磨试验及堆焊焊缝的显微观察,结合母材和堆焊焊接材料的成分特点及2种不同的堆焊工艺试验,对试验结果及工艺参数的选取进行了分析说明.     

汽车前轴辊锻模的表面堆焊再制造技术

介绍了汽车前轴辊锻模具的堆焊再制造工艺,包括焊前模具处理和模具预热,堆焊合金层,焊后退火热处理等。堆焊修复后的模具大幅度提高了辊锻模具寿命。     

支承辊镶套修复

针对大型支承辊采用堆焊修复而使辊面组织不均匀的问题,采用了支承辊镶套修复技术,根据支承辊的使用情况设计镶套轧辊的配合直径及联接过盈量,根据配合直径及过盈量确定热装温度,保证安装顺利进行.支承辊镶套修复后,镶套轧辊联接紧固,可以满足支承辊使用性能.实际使用中效果良好.     

60CrMnMo钢轧辊堆焊修复及热处理工艺

在分析60CrMnMo钢轧辊堆焊修复和热处理工艺的基础上,研制了局部堆焊修复的焊接材料.选择Stellite muhipass 224药芯焊丝和HJ107焊剂作为整体轧辊堆焊材料,通过焊前预热、局部焊补、轧辊表面埋弧堆焊、焊后热处理等措施,成功修复了尺寸为φ1150mm的60CrMnMo钢轧辊.实践证明,经该工艺处理后轧辊使用寿命提高0.5倍.     

面向零件形状的计算机图形库的开发

论述了CAD技术中参数化设计的三种建模方法，重点介绍了基于特征的参数化建模原理。在此基础上，分析机械设计中的机构结构，归纳出其零件的几何特征构成。设计了机构CAD图形库，并提出了该图形库生成步骤和人机交互界面。     

FeCrAIW电弧喷涂层组织的致密化研究

采用激光辐照对FeCrAlW电弧喷涂层的组织进行致密化处理,借助扫描电镜和X衍射对涂层的组织进行了分析.测试了涂层的显微硬度.结果表明:涂层组织致密度提高,孔隙率明显降低.随着激光扫描速度的增加,涂层的显微硬度降低.在较低的扫描速度下,涂层与基体之间形成互熔区,涂层与基体之间产生良好的冶金结合.     

Prospects of the Use of Synergetic Approach to Solution of Problems of the Science of Nanomaterials

A synergetic approach to solution of problems of self-controlled synthesis of nanostructures and creation of self-organizing nanotechnologies is considered in connection with the superproblem of creation of materials with functional properties resembling those of biosystems. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 55 – 61, July, 2005.     

Kinetics of the oxidation of metals — Influence of self-diffusion of metal

The importance of the self-diffusion of a metal during its oxidation by a gas is treated for the cases of nonstoichiometric oxides having either interstitial cation or cation vacancies. We have established a general relationship for the reaction rate when a mixed diffusion process occurs. From this relationship, we have shown that the pressure dependence can be different, according to whether the rate-determining process is the self-diffusion through the metal or through the product.     

Features of formation of the structure in production of blanks of disks of heat-resistant nickel alloys

Conclusions To provide a high level of mechanical properties in wrought blanks of cast ÉP741NP and ÉP962 alloys it is necessary to form controlled structures. A necklace-type structure formed in homogenizing isostatic treatment, subsequent thermomechanical working including alternation of the operations of deformation in the (+)-area and recrystallization anneals, and final heat treatment is preferable. The temperature conditions of all stages of thermomechanical working are strictly controlled, especially the final operation of deformation and heating for hardening. To eliminate hardening cracks and distortions it is necessary to use molten salts at t=600°C as quenchants. The use of multiple production operations makes it possible to significantly reduce the structural inhomogeneity related to inhertance of the original dendritic structure. However, the structure of the final semifinished product is nevertheless characterized by a difference in occurrence of the processes of polygonization and recrystallization between the former dendritic cells and the interdendritic spaces in deformation and heat treatment.To obtain structurally homogeneous blanks for gas turbine engine parts it is necessary to use basically new methods of remelting such as vacuum double electrode remelting and electron beam remelting with an intermediate vessel.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 25–29, December, 1991.     

Ab-initio calculation of enthalpies of formation of intermetallic compounds and enthalpies of mixing of solid solutions

A large number of ab-initio calculations of energies of formation of intermetallic compounds have been performed in the last 15 years. The currently used methods are listed. The paper presents a review of the aluminium based compounds which have been studied. Comparisons of calculated and experimental enthalpies of formation are provided for aluminim-3d and-4d transition metal alloys at equiatomic composition. The modelling of the enthalpies of mixing of solid solutions based on a given lattice is described.     

试论洋务派教师聘任的思想

洋务派在洋务学堂的办学活动中,为了解决西学专业学科的教学困难,采用了聘请外籍教师的应急措施.他们以真才实学,合同制管理作为主导思想,并认为这种解决师资的途径只是权宜之计,并非久远.从客观上看,洋务派的教师聘任思想有深刻的历史影响.