低碳硫铋易切削钢的生产工艺实践

总结了低碳硫铋易切削钢1214Bi生产过程中为保证轧材质量在冶炼、连铸及轧制工艺上采用的关键措施。生产实践表明,1214Bi易切削钢轧材夹杂物分布均匀,钢中铋颗粒细小均匀,产品切削性能良好。     

Ca-S复合易切削奥氏体不锈钢在微波元件——N型同轴转换接头上的应用

随着轻工,电子工业以及精密机械工业的发展,易切削不锈钢使用量日益俱增。S系易切削不锈钢虽有很好的切削性能,但其冷热加工性能,耐腐蚀性能不良,使其用途受到限制。六十年代西德、日本先后研制成功了Ca易切削钢并实现了工业化生产。使用证明,Ca易切削钢采用超硬工具和高速切削加工时能显著提高钢的切削性能、ca易切削     

环保型含Bi低碳高硫易切削钢的开发

开发Bi易切削钢1215M(%:0.06C、0.04Si、1.25Mn、0.39S、0.17Bi)替代Pb易切削钢SUM24L。生产Bi易切削钢的流程为40t UHP EAF-40t LF(喂Bi线)-180 mm×180 mm连铸-连轧工艺。试验结果表明,Bi易切削钢1215MΦ9 mm盘条夹杂物分布均匀,Bi易切削钢1215M的切削性能优于SUM23HS含S易切削钢与SUM24L含Pb易切削钢相当。     

硫系易切削钢C1118的工艺实践及其组织性能

通过合理的化学成分以及冶炼、连铸和轧制工艺的设计与控制,开发了一种硫系易切削钢C1118,并进行了工艺实践,成功生产了28mm的圆钢。通过金相显微镜、扫描电镜、能谱仪和Leica图像仪对其组织、夹杂物进行了观察分析,结果表明:该工艺下生产的易切削圆钢疏松等级良好,基体组织为铁素体和少量的珠光体,MnS以长条状或纺锤状存在,可以细化铁素体组织并改善钢的切削性能。开发的易切削钢C1118的力学性能满足供货要求,切削性能优异,磨损速度明显低于45号钢,相对于45号钢的加工性Kr为1.62。     

连铸工艺开发SAE1141汽车用易切削钢

采用EAF—LF—CC工艺生产SAE1141汽车用易切削钢,对连铸坯内在质量、轧材表面质量等问题进行了控制,并对连铸、连轧生产的SAE1141钢进行了各项性能的检测,钢材性能可满足汽车零部件的要求。采用连铸工艺生产SAE1141,在成材率方面比模铸提高10％以上。连铸时要采取措施防止水口结瘤及连铸坯表面裂纹。为提高切削性能,连铸时需对硫化物形态进行控制。     

亚共析石墨化易切削钢的开发

 石墨易切削钢是顺应易切削钢无铅、低硫这一发展趋势而提出的。具有亚共析组织的钢种其石墨化过程一直很难,因此该钢种开发的关键是促进其石墨化过程。基于增加石墨核心来加速石墨化过程进行了钢种的成分设计与研制。结果表明,正是开发钢中具有与石墨结构（简单六方）相同的BN成为了石墨的形核位置,从而有效促进了开发钢的石墨化过程。开发钢的组织由铁素体和石墨组成,其中,石墨的缺口效应和润滑效果赋予了开发钢较高的切削性能和冷成形性能。     

Y45S20易切削钢的工艺开发

在Y45S20易切削钢开发过程中对其关键工艺作了调整和改进，特别是在连铸大批量生产中对各工艺要点的控制以及对各主要成份的分期控制，使Y45S20易切削钢易有合理的成份分布，较好的机械性能和优异的切削性能。     

国内外易切削钢综述

综述了国内外易切削钢概况，重点介绍了五种常见易切削钢系列钢种及其特性，并指出了易切削钢的发展方向。     

轿车连杆用易切削非调质钢YF35MnV的试验

采用高碱度炉渣、直接脱氧和扩散脱氧相结合的超低氧钢生产工艺、稳定的增氮增硫技术、控制硫偏析的连铸工艺,成功开发了轿车发动机连杆用易切削非调质钢YF35MnV,该钢种的各项性能指标满足轿车连杆用钢的要求。     

碲系易切削钢及其切削性评价

硫系易切削钢利用硫化物的脆断性来提升钢材的切削性能,硫化物的形态、大小、分布是决定易切削钢切削性能优劣的关键因素.上海大学与芜湖新兴铸管有限责任公司合作,通过在1215MS易切削钢基础上添加碲元素,来改善硫化物的形态及分布,提升产品的切削性能.结果表明:硫系易切削钢添加质量分数0.016％ 的碲后,易切削钢中硫化物三维...     

海洋平台用钢的研发生产现状与发展趋势

介绍了国内外海洋平台用钢发展现状,总结出海洋平台用钢生产的主要特点,对传统海洋平台用钢的成分、工艺、组织、性能特征及其局限性进行了分析,提出了开发"Mn/C"合金化新型高强韧海洋平台用钢的发展思路,对海洋平台用钢今后的发展趋势加以展望。鉴于我国高级别海洋工程用钢与国外相比仍存在一定的差距,关键产品还依赖于进口,今后应重点研制屈服强度为690 MPa级的海洋平台用高强韧钢。     

连铸小方坯生产高质量特殊钢线材

综合论述了国际上用连铸小方坯生产高碳钢（包括轮胎钢）、弹簧钢、冷镦钢等特殊钢线材的工艺路线,比较了大、小方坯连铸的区别及用小方坯连铸生产这些钢种所采取的质量和工艺措施。     

攀钢1#连铸坯生产大型材最小压缩比探讨

介绍了当今钢铁企业对钢材最小压缩比的规定,并分析了随着炼钢浇注及轧制技术的进步,压缩比可以逐步减小。本文通过对攀钢连铸坯45#轧材检验结果进行分析,以及根据攀钢连铸坯碳合结轧材近140000t无力学性能质量外事异议情况,总结出其压缩比达到3.39时,产品可达到国家优质钢材标准的要求;当连铸坯的纯净度相当好时,压缩比为2.28亦能满足国家标准要求。     

特殊钢方坯连铸的发展

为满足成品棒材组织结构的要求，生产齿轮钢、高碳铬轴承钢等合金钢的连铸坯断面直径在350mm以上为宜，减少中间包钢水过热度，采用铸模电磁搅拌和低速浇铸等可防止柱状晶裂纹和减少中心疏松和偏析。     

高强度非调质冷镦钢研究和开发现状

根据国内外高强度非调质冷镦钢的研究和开发现状,分析和讨论了800～1 200 MPa高强度非调质冷镦钢的化学成分、工艺特点、组织和力学性能。高强度非调质冷镦钢应具有高的强度和有良好的冷成形性,其热轧材的强度和硬度应控制在一个合适的范围内。采用低碳高锰及微合金化的成分系列,通过热机轧制工艺,该钢种能获得良好的组织和力学性能。     

Alternatives to Lead as a Machinability Enhancer in Free Cutting Steels

Low levels of lead are added to free cutting steels to improve machinability. For environmental reasons, there is interest in alternatives to lead that are technically and commercially viable. The machining performance of eight low carbon free cutting steels with alternative machinability enhancers, including additions of bismuth, increased sulphur (with and without tellurium), tin and phosphorus, has been investigated. In tests with high speed steel tools and lubricant, the leaded steel showed the best performance in terms of production rate, surface finish and chip form. In tests with coated carbide tools at a range of cutting speeds the standard non‐leaded 11 SMn30 steel performed well in terms of tool wear, but showed poorer chip form than the leaded steel. The steels with increased sulphur showed improved performance compared with the 11SMn30 steel in tests using high speed steel tools and lubricant, but did not approach the leaded steel in terms of production rate. The steels containing tin did not generally perform better than the 11 SMn30 steel. The 11 SMn30Bi steel gave performance approaching that of the leaded steel in tests with high speed steel tools and lubricant. However, the cost of this addition may make it uneconomic for large scale use.     

低碳高硫易切削钢LF精炼工艺研究

硫易切削钢因其良好的可切削性能和作为含铅易切削钢的环保替代品,在机加工行业已得到广泛使用。石横特钢通过对低碳高硫易切削钢LF精炼工艺的研究,改善了钢中硫化物形态,降低了脆性夹杂物出现的机率,显著提高了该钢的切削性能,满足了用户需求。     

Carbon or nitrogen alloyed quenched and tempered stainless steels - a comparative study

Some conventional stainless quenched and tempered steel grades were modified by substituting nitrogen for carbon and by variing the contents of chromium, molybdenum and nickel. Results of a comparative study of carbon and nitrogen steels are presented in a wide range of tempering temperatures. In nickelmartensitic steels nickel can be partially substituted by nitrogen without harming the properties. Due to their finer microstructure nitrogen steels with 15-17 %Cr, 2 %Ni and 0.2 %N, at the same strength level, offer higher toughness and better corrosion resistance than the respective conventional steel X20 CrNi 17 2.     

Application of Thermodynamic Model for Inclusion Control in Steelmaking to Improve the Machinability of Low Carbon Free Cutting Steels

Oxide inclusions formed during steelmaking processes influence the machinability of steel products. At moderate and high cutting speeds, the tool life is dominated by chemical wear. However this wear can be suppressed by engineering exogenous and indigenous glassy oxide inclusions in steel. The present work demonstrates a method to engineer glassy oxide inclusions in a low carbon free cutting steel applying a new thermodynamic model for deoxidation control of steel based on slag‐melt as well as melt‐oxide inclusion equilibration. The model is used online in an industrial production line for the controlled production of glassy inclusions. These inclusions are shown to improve machinability by lubricating the tool‐chip interface during machining of the steel at high cutting speeds. Using an inclusion engineered work piece, the crater wear of an uncoated P10 tool is significantly improved and the tool life is tripled at cutting speeds in the range between 200 and 400 m/min. The industrial results show that thermodynamic modelling is a powerful tool to produce free cutting steels with consistently good machinability behaviour.     

Lowcycle fatigue behavior on duplex stainless steels

Stainless steels are used predominantly for their corrosion resistance in moderate to highly aggressive environments. For construction purposes, engineers normally select carbon steel due to low cost, long experience, applicable design rules and a large variety of strength classes. However, different stainless steel types can also provide a very wide range of mechanical properties and they have the advantage of not needing surface protection. Duplex Stainless Steels (DSSs) in particular, are austeno-ferritic steels with twice the mechanical strength of conventional austenitic and ferritic stainless steels and have a potential use in construction. In the early 1980’s, a ‘second generation’ of duplex steels was introduced with better weldability mainly through nitrogen alloying. The most common duplex grade today is the UNS S32205/S31803, which is used in a great number of applications in a wide variety of product forms. This grade was the basis for the development of a ‘third generation’ of duplex steels. These higher alloys are called super-duplex stainless steels and identified as UNS S32750/S32760. The cyclic hardening-softening response, the cyclic stress-strain curve and the microstructure evolution of a high nitrogen duplex stainless steel S32750 have been evaluated and the results compared with reference to low and medium nitrogen duplex stainless steels, S32205 and S32900 grades, respectively. The beneficial effects of nitrogen on the cyclic properties of most modern alloys have been analyzed in terms of the flow stress components, i.e. the back and the friction stress. A phenomenological model is proposed to explain the influence of nitrogen atoms on the cyclic behavior of these steels.