钙处理条件对钢中夹杂物组成和形态变化的影响

钙处理条件对钢中夹杂物组成和形态变化的影响［日］木通口善彦等１绪言近年来随着耐ＨＩＣ钢评价法的超严化，成为ＨＩＣ裂纹起点的夹杂物的无害化已变得更为重要。为此，就需要通过加Ｃａ在钢液阶段优化夹杂物中的ＣａＯ－Ａｌ２Ｏ３组成，并抑制存在于夹杂物中的ＣａＳ...     

钢中夹杂物含量及其形态对钢力学性能的影响

在实验室１６ｋｇ真空感应炉上对铝镇静钢水用ＣａＯ－ＣａＦ２－Ａｌ和ＣａＯ－ＣａＦ２－Ａｌ－Ｃａ进行精炼处理，降低了钢中硫含量和总氧含量，研究了钢中氧化物和硫化物夹杂的含理及其形态对钢力学性能，尤其是冲击韧性的影响。钢水经钙处理后，钢中硫含量和总氧含量都可降低到１０ｐｐｍ以下，且钢中Ａｌ２Ｏ３和ＭｎＳ夹杂物能完全转变成硫化钙和铝酸钙，钢的转变温度低于－６０℃，而且钢的各向异性消失。     

车轮轮箍钢失效与夹杂物控制

钢中夹杂物是导致车轮轮箍疲劳失效的主要原因,尤其是Ａｌ２Ｏ３链状夹杂物的影响最大,在常规生产条件下,采用减铝和复合脱氧可有效减少钢中Ａｌ２Ｏ３夹杂;采用喷Ｓｉ－Ｃａ粉、喂Ｓｉ－Ｃａ线工艺对钢中Ａｌ２Ｏ３夹杂进行变性处理,以及在真空精炼工艺条件下,采用降低铝量和精炼后期用Ｃａ、Ｂａ系复合合金处理工艺,可显著降低车轮轮箍钢中Ａｌ２Ｏ３夹杂级别和数量,提高车轮轮箍钢的使用性能。     

SKF钢包炉精炼钢中Al_S含量对夹杂总量的影响

精炼车轮钢的化学成分(%)为:Ｃ0.60±0.02,Ｓｉ0.25±0.03,Ｍｎ0.75±0.03,Ｓ、Ｐ<0.020。钢中夹杂物采用ＡＳＴＭ标准评级,要求Ｂ类(Ａｌ2Ｏ3)夹杂<1级,Ａ类(硫化物)夹杂<2级、Ｃ类(硅酸盐)夹杂<2级、Ｄ(点状氧化物)夹杂<2级。为了保证车轮钢的质量,对工业生产中的数据进行了分析研究,确定出用铝的工艺参数。1　精炼工艺　　精炼炉采用90ｔＬＦＶＤ(ＳＫＦ)钢包炉,设有除渣、加热、真空处理3个工位,具有加热、电磁搅拌、成分微调、真空处理、吹Ａｒ搅拌等功能。工艺流程:初炼钢水→除氧化渣→脱氧造渣→ＬＦ(升温、脱氧、微调)→ＶＤ→搅拌…     

超低氧钢中夹杂物形态及分布规律

采用ＧＰＥＦ＋ＶＡＤ工艺冶炼低碳碳齿轮钢、氧含量平均达１０ｐｐｍ左右，改变了传统模铸钢中夹杂物分布规律，减小了脆性夹杂物尺寸，提高了钢材质量。     

铈对ZG75CrMo钢中非金属夹杂物及钢性能的影响

探讨了铈对ＺＧ７５ＣｒＭｏ钢中夹杂物及钢性能的影响。研究表明，与ＺＧ７５ＣｒＭｏ钢相比，ＺＧ７５ＣｒＭｏ（Ｃｅ）钢中夹杂物的含量减少且性态改变，塑韧性、抗热疲劳性和抗高温氧化性均有明显提高。     

钢包喂CaSi线对钢中夹杂物变性的影响

本文对钢包内钢水喂ＣａＳｉ线处理后,铝镇静钢中夹杂物的组成、形态、尺寸和分布等变化规律作了较详细的研究。研究结果表明,喂线后钢中钙铝比达到０．０９以上时,钢中的Ａｌ２Ｏ３类夹杂物能获得较好的变性;并且夹杂物中的钙铝比随喂线后钢中钙铝比的增大线性增加;较高的钢中钙铝比有利于连铸坯中大颗粒夹杂物的去除,有利于钢中夹杂物球化率的提高。     

15MnHP钢夹杂物行为研究

针对武汉钢铁公司二炼钢厂ＬＤ－钢包吹氩处理－ＣＣ生产１５ＭｎＨＰ钢的工艺，对钢包，中间包和铸坯中夹杂物进行系统的研究，为进一步改善１５ＭｎＨＰ钢清洁度提供了依据。     

改善弹簧钢中氧化物夹杂形态的热力学条件

为了控制钢中析出氧化物夹杂的组成和形态,通过钢液－夹杂物、钢液－熔渣之间的化学平衡关系,以弹簧钢为例,计算了１８２３Ｋ时钢中强脱氧元素钙和铝的残余含量对析出夹杂物组成的影响,并给出了可使钢中析出具有良好变形能力的ＣａＯ．Ａｌ２Ｏ３．２ＳｉＯ２夹杂物的钙、铝含量的控制范围和控制方法。     

钢包喂CaSi线对钢中夹杂物变性的影响

在生产铝镇静钢的工艺条件下,研究了钢包喂Ｃａｓｉ线处理后钢中夹杂物的组成、形态、尺寸和分布等的变化规律。结果表明,喂线后钢中钙铝比达到０．０９以上时,钢中的Ａｌ２Ｏ３类夹杂物能获得较好的变性;夹杂物中的钙铝比随喂线后钢中钙铝比的增大呈线笥增加趋势;较高的钢中钙铝比有利于连铸坯中大颗粒夹杂物的去除,有利于钢中夹杂物球化率的提高。     

Effect of sintering atmosphere on densification,mechanical properties and diamond stability of prealloyed diamond impregnated composites obtained by free sintering

Abstract

The sintering behaviour of prealloyed powder compacts has been studied as a function of the sintering atmosphere in free sintering experiments. Atmospheres with different hydrogen/nitrogen ratios and even vacuum have been used in the sintering cycles. Powder compacts with and without diamond additions have been sintered. Three different grades of diamond were used in the experiments, all of them synthetic manmade diamond. Two had different levels of metallic inclusions and one was coated with Ti. The interaction between bond/atmosphere/diamond has been characterised analysing the density, microstructure, bend strength and degradation of the diamonds after dissolving the matrix. Diamonds from atmospheres with low hydrogen content show evidence of strong degradation. Moreover, any diamond additions strongly decrease the strength of the bonds, acting as defects. The strength is also affected by the sintering atmosphere and sintering temperature but not significantly by the type of diamond.     

Effect of Y2O3 and Dy2O3 on Microstructure and Mechanical Behaviors of Aluminum Nitride Ceramics

The effects of two types of additives, Y2O3 and Dy2O3, on the sintering and mechanical behaviors of AlN ceramics were investigated. The experimental results show that the sintering temperature can be decreased and the mechanical behavior can be improved by adding rare earth in AlN ceramics. The strength of AlN ceramics with Y2O3 and Dy2O3 are 326 and 320 MPa, respectively, which are 97.6% and 93.9% higher than the un-doped AlN ceramics. The fracture behavior on the fracture surfaces of rare earth oxide AlN ceramics was found to be a mixed mode of transgranular fracture and intergranular fracture. As a result, it is concluded that the improvement of bending strength of AlN ceramics with Y2O3 and Dy2O3 addition are mainly achieved by strengthening the grain boundary.     

Roles of rare earth oxide additives in millimeter-wave sintering of AlN

Roles of rare earth oxide (RE2O3) additives in millimeter-wave(MM) sintering of AlN were investigated from the standpoints of phase diagram, heating characteristics of rare earth oxides, and morphology of intergranular oxide phase. In the millimeter-wave sintering of AlN, densification temperature decreased with the decrease of the ionic radius of rare earth ion and was closely related with the eutectic temperature in the RE2O3-Al2O3 binary system. The lowest densification temperature in the millimeter-wave sintering of AlN with Yb2O3 additive was attributed to the largest heating rate of Yb2O3·Al2O3 binary oxide under millimeter-wave radiation. Furthermore, the lowest densification temperature could be attained while selecting the Yb2O3 content so as to form the intergranular phase with the eutectic composition in the Yb2O3-Al2O3 binary system. The result showed good agreement with the above mentioned during the sintering of Si3N4 with Yb2O3-Al2O3 additive. From TEM observation, it was verified that film-like intergranular oxide phase formed under millimeter-wave radiation was favorable for attaining high thermal conductivity in the Yb2O3 added AlNs.     

稀土及烧结温度对铁基胎体力学性能的影响

采用正交设计和方差分析的方法 ,研究了烧结温度、稀土种类及添加形态、稀土含量对金刚石工具用Fe基金属胎体力学性能的影响。实验结果表明 ,烧结温度的影响特别显著 ;稀土种类及添加形态的影响不大 ;稀土含量在 0 .2 %～ 0 .4 %之间时 ,对胎体的力学性能的提高最明显 ,继续增加稀土含量 ,对胎体性能的影响不大     

Effect of Rare Earths on the Quality of Brush-plated Coating

ＥｆｅｃｔｏｆＲａｒｅＥａｒｔｈｓｏｎｔｈｅＱｕａｌｉｔｙｏｆＢｒｕｓｈｐｌａｔｅｄＣｏａｔｉｎｇＬｉＭｕｑｉｎ（李慕勤），ＭａＣｈｅｎ（马臣）（ＪｉａｍｕｓｉＩｎｓｔｉｔｕｔｅｏｆＴｅｃｈｎｏｌｏｇｙ，Ｊｉａｍｕｓｉ１５４００７，Ｃｈｉｎａ）Ｌｉ...     

稀土在H13模具钢低温粉末渗硼中的应用

对低温加稀土粉末渗硼进行了研究，初步探讨了稀土含量和工艺因素对渗层组织和性能的影响。结果表明，在低温下，加稀土渗硼仍具有比较明显的“滑化”效果，能够提高渗硼层的耐磨性；合适的稀土加入量促使渗层趋向均匀、致密，并有一定的催渗作用。     

添加剂对预合金粉末胎体性能及其金刚石工具使用效果的影响

研究了ＴＴ１５预合金粉末及添加适量其他成分后的烧结性能，对金刚石的包镶与粘结性能及其组织结构，确定了该种粉末作为金刚石工具胎体的制造工艺条件，指出以ＴＴ１５合金粉末为基，通过添加适量铜合金或钴，可以得到适用于不同石材的金刚石工具胎体。     

石材切割锯片金刚石刀头磨损状况的研究

研究了花岗石锯切过程中金刚石锯片刀头的磨损状况,对刀头结合剂和金刚石磨粒的磨损机理进行了分析,并探讨了金刚石磨粒的磨损形态对金刚石锯片锯切性能的影响。     

Effect of Rare Earth Additives on Chrome-Plating Quality

Electroplatingisoneofthetraditionalprocessesof decorationandsurfaceprotection.Boththeelectroplate principleandprocessparameterscanformacomplete setofsystem.However,therestillexistsixmostseri ousproblemssuchasthepoorcombinationstrengthof electroplatecoatin…     

Composition, Processing Technology and Property of Ceramic Die Materials Containing Rare Earth Additives

Development and application of new ceramic die materials is one of the important topics in the field of die research. The composition, processing technology, mechanical property and engineering performance of the ceramic materials such as cermet, ZTA, TZP, TZP/Al2O3, TZP/TiC/Al2O3, PSZ and Sialon, etc., with rare earth yttrium, lanthanum and cerium, and so on working as additives, were investigated and analyzed in the present study. Problems existed in the research and application of rare earth ceramic die materials were discussed. Rare earth additives can effectively improve the mechanical property and engineering performance of ceramic die materials. Thus, it will have further perspectives of wider application. More attention should be paid in the future to the toughening and strengthening of the ceramic die materials, the adding forms and kinds of rare earth elements and acting mechanisms of rare earth additives in ceramic die materials.