硅铝钡作终脱氧剂的试验

介绍了用硅铝钡合金代替硅钙合金和硅铝失对钢水进行终脱氧试验的情况。试验结果表明：本工艺可降低风中氧含量及夹杂物含量,改善钢材机械性能,提高经济效益,改善工作一半。     

环境温度对船用耐蚀钢腐蚀行为的影响

 采用国际海事组织（IMO）模拟油轮货油舱内底板环境试验方法,对比分析了传统船板和耐腐蚀船板的腐蚀失重与腐蚀形貌,深入研究了环境温度对船用耐蚀钢腐蚀行为影响规律。结果表明,环境温度对船板腐蚀行为存在显著影响,随着环境温度（30~50℃）的升高,点蚀坑的数量逐渐增多,点蚀坑深度先增大后减小,在45℃时达到峰值。2种钢点蚀行?畋鸾洗螅炒甯值闶纯拥纳疃戎本侗龋╤/D）随环境温度的增大而增大,而耐蚀船板则呈现逐步下降的趋势。耐蚀合金元素的加入有效降低了船板钢在不同温度下的腐蚀速率,减小了钢的点蚀坑数量,改善了点蚀坑的扩展方式。即点蚀坑由纵向深度方向扩展,转为横向表面方向扩展,有效提高了船板的安全性。     

强酸性氯离子环境下低合金钢的点蚀行为

 参照国际海事组织（IMO）发布的《油轮货油舱耐蚀钢性能标准》中所规定的模拟内底板试验方法,对比研究了在强酸性高氯离子浓度的环境下,传统低合金钢和耐蚀低合金钢的腐蚀速率及点蚀行为随温度变化的规律。试验结果表明,添加铜、镍元素的耐蚀低合金钢腐蚀速率较传统低合金钢最高降低了90%以上,并且具有优于传统低合金钢的抑制点蚀增殖、扩展的性能。耐蚀低合金钢表面及点蚀坑内部分布有白色颗粒,为铜元素的再沉积所致。该纯铜颗粒分布于试验钢表面可以有效提高钢的腐蚀电位,在点蚀坑内部的富集可以有效抑制点蚀坑在深度方向上的扩展。     

不同脱氧方式对低合金高强钢局部腐蚀性能的影响

采用Al脱氧和Zr-Ti复合脱氧方式对低合金高强钢进行脱氧,利用金相显微镜和扫描电镜观察不同脱氧方式下钢材组织形貌以及夹杂物等方面的差异。根据俄罗斯GOST 9.911—89标准进行室内模拟海水加速腐蚀试验以及电化学试验,探究不同脱氧方式对低合金高强钢局部腐蚀稳定性的影响。研究结果表明,2种脱氧方式形成的夹杂物均为细小氧化物。传统Al脱氧样品中的夹杂物呈球状或呈线性汇集,Zr-Ti复合脱氧样品中的夹杂物则主要呈球状均匀分布。采用Zr-Ti复合脱氧样品的局部耐海水腐蚀性能比常规Al脱氧样品更优异,ZrTi复合脱氧钢平均腐蚀速率比Al脱氧钢减小17.27%。同时,采用Zr-Ti复合脱氧,能有效控制夹杂物的类型、尺寸与分布,尺寸主要分布在1~5μm,Zr-Ti复合氧化物弥散分布于基体中,降低了点蚀诱发敏感性,提高了其耐海水局部腐蚀稳定性。     

夹杂物对低合金钢点蚀诱发敏感性的影响

为了进一步提高低合金钢的抗点蚀性能,采用Ti/Al脱氧及Ca处理工艺熔炼并轧制制备了试验钢。利用场发射扫描电镜及能谱仪(SEM-EDS)、电化学极化试验及浸蚀前、后夹杂物的原位观测,研究了不同脱氧工艺钢中夹杂物在模拟海水介质中诱导点蚀的行为。结果表明:与Al脱氧钢相比,Ti脱氧钢中形成了富含Ti Ox、数量更多、尺寸更细小的夹杂物,有利于Mn S的局部分散析出,降低其诱发点蚀的危害,采用Ti脱氧工艺有助于提高钢的抗点蚀性能;Mn S诱发点蚀的能力强于氧化物夹杂,点蚀优先在Mn S夹杂与基体的界面处及夹杂物曲率半径小的区域萌生;降低夹杂物的腐蚀活性应该以调控夹杂物的组成为基础,其次优化夹杂物的形貌(球形化),在微米级范围内,夹杂物尺寸对点蚀诱发的影响最小。     

稀土耐候钢中的夹杂物及耐点蚀性能研究

利用电子探针、扫描电镜及能谱仪、图像分析仪对含稀土和不含稀土耐候钢中夹杂物的成分、形貌、尺寸等进行了研究。钢中加入稀土后,小球状的稀土硫化物和稀土氧硫化物夹杂取代了钢中原有的有害的长条硫化锰夹杂。对于低硫低氧(S:～0.004%,O:～0.002%)的耐候钢,0.0065%～0.016%的稀土含量保证了钢中夹杂物的良好变质效果,变质后的夹杂弥散分布而且85%以上的稀土夹杂物都小于2μm。通过干湿周期浸润实验室加速腐蚀试验研究了Cu-P-RE耐候钢和对比Q235钢的耐蚀性能。通过电化学极化试验和扫描电镜分析研究了稀土耐候钢中的夹杂物诱发点蚀行为。结果表明,微米级弥散分布的稀土夹杂取代了易腐蚀的长条硫化锰夹杂,减弱了钢中的微区域电化学腐蚀,从而抑制了钢中点腐蚀的发生和扩展。并可以诱发耐候钢表面发生均匀的全面腐蚀,促进均匀致密保护性锈层的生成。Cu-P耐候钢中加入适量稀土提高了钢的点蚀电位和耐点蚀能力,降低了耐候钢的腐蚀速率,提高了其耐蚀能力。     

采用石油液化气进行钢液脱氧

在实验室利用石油液化气对钢中氧进行去除.研究结果表明:利用石油液化气对钢液脱氧是可行的,配合VD真空冶炼,可用于生产高碳、高质量洁净钢.钢液脱氧时,通入氩气和液化气两者的混合气体的脱氧效果优于单纯通入单一气体,钢中氧含量下降更明显,碳含量增加幅度更低.混合气体对钢液脱氧操作8 min后,钢中脱氧减慢,氧含量下降不明显.钢液脱氧的起始阶段,钢中碳含量增加较为缓慢,当钢中氧含量降低到一定水平后,钢中碳含量迅速增加.通入氩气,加强了钢液搅拌,在一定程度上抑制钢中氢含量的增加速度,促进了钢中氢的去除.      

AlCaC复合脱氧剂在转炉炼钢中的应用

日钢在60t转炉上试验采用AlCaC作为Q235B钢的终脱氧剂,并与目前使用的SiAlTi脱氧合金进行了对比,结果表明.AlCaC复合脱氧剂能有效降低钢中全氧含量,提高钢水质量,钢水浇注良好,铸坯内部组织致密,钢材力学性能优良,并且吨钢降低脱氧成本0.60元.     

石钢降低钢中氧含量生产实践

介绍了石钢转炉厂为降低钢中氧含量采取的一系列措施,如高拉碳、提高一次倒炉率、降低出钢温度、控制下渣量、精炼白渣脱氧等,氧含量由2001年的50.04×10-6下降到2004年2月的19.13×10-6,取得了显著效果,钢材质量明显提高。     

铝锰钛复合脱氧合金在转炉炼钢中的应用

在25t转炉上试验采用AlMnTiFe合金做为Q235B钢的终脱氧剂，与SiAlCa合金进行对比。结果表明，AlMnTiFe复合脱氧合金能有效降低钢水全氧含量，提高钢水质量；采用AlMnTiFe脱氧后，钢水浇注良好，铸坯内部组织致密，钢材力学性能优良；AlMnTiFe合金代替SiAlCa合金进行终脱氧，可降低吨钢脱氧成本0．84元。     

Effects of deoxidizing degree on the pitting corrosion behavior of carbon and manganese steels

Nine steels with different deoxidizing degrees and two comparative steels were selected. Their pitting initiation susceptibility was compared by means of potentiodynamic polarization tests in 3wt% NaCl solution. The pit propagation rate was evaluated in artificial sea water and 3wt% sea salt solution by simulating occluded corrosion cell (SOCC) test and hanging plate test, respectively. The composition of inclusions and corrosive feature were studied by scanning electron microscopy (SEM), electron probe micro-analysis (EPMA), and optical microscopy (OM). The results indicate that sulfide inclusions in steel are the sites for pit nucleation. The sulphide inclusions vary in shape from short spindle-like to long strip-like with increasing deoxidizing degree. Under the same conditions, the lower the deoxidizing degree gets, the lower the pitting initiation susceptibility becomes, and the stronger the resistance to pit propagation exhibits. For steels with different deoxidizing degrees, their pitting initiation susceptibility is mainly influenced by thermodynamic stability, while the pit propagation rate is primarily subject to the characteristics ofinclnsions in steel.     

核电站设备制造中双相不锈钢的应用

奥氏体-铁素体双相不锈钢中稳定存在奥氏体相和铁素体相,该钢具有较高的机械性能和优异的耐点蚀、晶间腐蚀和应力腐蚀性能,在核电站设备制备中被广泛应用。一般双相不锈钢铸件中铁素体相的体积分数≤20%,服役温度≤425℃,双相不锈钢锻件中铁素体相约占50%,服役温度≤250℃。文中介绍了核电站设备中应用的双相不锈钢铸、锻件的化学成分、制造和焊接工艺要求及组织和性能。     

Effects of rare earth on inclusions and corrosion resistance of 10PCuRE weathering steel

The types,morphologies and distributions of nonmetallic inclusions in Cu-P weathering steels with and without rare earth were analyzed through a quantitative image analyzer,scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)attached to SEM.Solid-soluble content of rare earth in the steels was analyzed by non-aqua electroanalysis and ICP.The results showed that rare earth modified the types and the morphologies of inclusions in the weathering steels.The small spherical rare earth oxysulfides and rare earth sulphides replaced the elongated MnS inclusions in the RE weathering steels.The rare earth inclusions dispersedly distributed and most inclusions were smaller than 2 μm in size.The optimum content of RE was 0.0065%-0.016% for 10PCuRE weathering steels containing about0.002% oxygen and 0.004% sulfur.Solid-soluble content of rare earth in steels was(14-20)x 10-6,which can act as a micro-alloying element.The corrosion resistance of 10PCuRE weathering steels and Q235 were studied by dry-wet cyclic immersion test.Their corrosion rates were obtained respectively.The polarization curves and pitting corrosion behaviors of weathering steels with and without rare earth were measured by electrochemical methods.The corrosion resistance of Cu-P weathering steels was improved by adding an appropriate amount of rare earth.Less and fewer rare earth inclusions largely decreased pitting susceptibility and rate of pit propagation.The pitting potential and the resistance against pitting corrosion of the RE weathering steel were significantly improved due to the modification of rare earth to inclusions.     

双相不锈钢成分、性能及析出相分析

叙述了常用的超级双相不锈钢的成分、耐蚀性和应用,分析了不同种析出相、有害相、点蚀当量值(PRE)及焊接对双相不锈钢组织和性能的影响,得出通过控制合金化成分,调整点蚀当量值,编制合理的热处理工艺,严格控制有害相析出,使两相比含量比值接近1,可获得良好耐蚀性、高强度和耐磨性的双相不锈钢。     

氧化物冶金在高强度低合金钢生产中的试验研究

通过对氧化物冶金技术在高强度低合金钢生产中的试验研究,探索采用氧化物冶金技术冶炼过程中转炉终点及LF精炼过程钢中的氧含量控制、正确的脱氧方式、脱氧合金元素的加入时机等,通过调节钢液成分,确保形核诱导粒子的生成;同时,利用扫描电镜分析了钢中夹杂物的成分、形貌、尺寸及夹杂物周围的组织形貌,并对试验钢板的性能进行了取样检测。结果表明,试验炉次氧化物冶金的效果良好且试验钢板性能很好。     

Corrosion Resistance of Different Metallic Coatings on Press‐Hardened Steels for Automotive

The corrosion resistance of laboratory press‐hardened components in aluminized, galvanized or galvannealed boron steels was evaluated through VDA 621‐415 cyclic test for the automotive industry. 22MnB5 uncoated steel for hot stamping and standard galvanized steel for cold forming were also included as references. Corrosion resistance after painting (cosmetic corrosion) was quantified by measuring the delamination of electro‐deposited paint from scribed panels. The rusting on their edges was used for determining the cut‐edge corrosion resistance. The corrosion resistance on unpainted deformed panels (perforating corrosion) was quantified by mass losses and pit depth measurements. Zinc‐coated boron steels were found to be more resistant to cosmetic corrosion than the other materials, and slightly more resistant to cut‐edge corrosion than the aluminized one. Red rust apparition could not be avoided due to the high iron content in all these hot‐stamped coatings. The three coated boron steels showed similar performances in terms of resistance to perforation. Aluminized boron steel presents the advantage of being less sensitive to hot‐stamping process deviation. Its robustness has been proved for many years on cars.     

Solidification and microstructure of a high alloy stainless steel

The steel considered in the present work can be classified as a 6Mo austenitic stainless steel, which has a much higher corrosion resistance than many other commercially available stainless steels. However, because of macrosegregation during solidification of ingot casting, the high alloy content in the steel, especially Mo, N, C, enhances precipitation of intermetallic phases such asa phase. Such precipitation mainly occurs in the center of the material and has normally no significant effect on mechanical properties or surface corrosion resistance. The introduction of modern production methods such as continuous casting of slabs for stainless sheet production has reduced the macrosegregation tendency and related precipitation. However, the microsegregation in a small scale may be enhanced as the higher cooling rate prevents the diffusion in the solidified region. In the present work, the continuous casting solidification process was simulated in a laboratory gradient     

超级高氮奥氏体不锈钢的耐腐蚀性能及氮的影响

用电化学测试、化学浸泡等方法研究了超级奥氏体不锈钢00Cr24Ni22Mo7Mn3CuN(654SMO)的耐点腐蚀和耐缝隙腐蚀的性能。通过改变氮含量,研究了氮对奥氏体不锈钢的耐点腐蚀和耐缝隙腐蚀性能的影响,结果表明,氮和适量的铬、钼结合,能显提高奥氏体不锈钢的耐点腐蚀和缝隙腐蚀的能力,并且随着氮含量的增国,砥体不锈钢的耐点腐蚀和耐缝隙腐蚀的能力也增强,对比实验表明,超级奥氏体不锈钢在耐点腐蚀,缝隙腐蚀等局部腐蚀性能方面可以和镍基合金C－276媲美,甚至优于镍基合金。     

The effect of nitrogen additions upon the pitting resistance of 18 pct Cr, 18 pct Mn Stainless Steel

The effect of nitrogen additions upon the pitting resistance of 18 pct Cr, 18 pct Mn stainless steel has been investigated by potentiokinetic techniques in a 1000 ppm NaCl solution. Nitrogen additions increased the pitting resistance of the steel irrespective of structure, however, the ferritic steel was less pit resistant than the (duplex) steels containing both austenite and ferrite which, in turn, were less pit resistant than the totally austenitic steels. For steels having a duplex structure, the effect of nitrogen on the pitting resistance was observed to follow a linear function of the relative amount of austenite in these steels due to the area effects of the austenite and ferrite which are galvanically coupled in these steels. The addition of nitrogen was found to increase the amount of austenite at a rate of approximately 200 times the percent nitrogen addition from 36 pct austenite for the 0.02 pct N steel to 100 pct for the 0.40 pct nitrogen steel. The addition of nitrogen to the totally austenitic steels increased the pitting resistance at the rate of approximately 0.31 volts per pct nitrogen added, but no mechanism was found for the increased resistance. This paper is based on a presentation made at a symposium on “New Developments in Ferritic and Duplex Stainless Steels,” held at the Fall Meeting in Cleveland, Ohio, on October 19, 1972, under the sponsorship of the Corrosion Resistant Metals Committee of TMS-IMD and the Corrosion and Oxidation Activity of the ASM.     

表面处理对海洋工程用316L不锈钢耐点蚀性能的影响

316L不锈钢为常用的耐蚀合金材料,然而其在海洋大气环境服役时易遭受点腐蚀而发生失效。通过点腐蚀速率、临界点蚀温度、点蚀电位、极化曲线测试等评价方法,对经过不同表面处理(光亮退火、抛光、酸洗钝化)后的316L不锈钢的耐点蚀性能进行测试分析。结果表明,不同表面处理对316L不锈钢的临界点蚀温度影响不大,但会使点腐蚀速率、点蚀电位有所差异;在测试条件下,抛光及酸洗钝化均可有效提高316L不锈钢的耐点蚀性能,其中酸洗钝化态的耐点蚀性能最好,因此建议对海洋工程用316L不锈钢产品在使用前进行酸洗钝化处理。