析出相的微区电位差对搪瓷用钢板贮氢能力的影响

为了探究TiN、Ti(C,N)、MnS等析出相的微区电位差与搪瓷用钢抗鳞爆性能的关系,选取3种不同成分的搪瓷用钢板,利用扫描电镜、透射电镜、原子力显微镜及电化学氢渗透试验,研究了3种钢板的析出相电位差和抗鳞爆性能。研究发现,搪瓷用钢板中不同种类析出相电位差存在差异,随着不可逆陷阱析出相微区电位的增加,钢板的有效扩散系数减小,抗鳞爆能力增强。其中,含有MnS析出相的微区电位差最大,具有最好的贮氢能力;Ti的碳氮化合物析出相的电位差较小,贮氢能力相对较弱。     

Ti-IF冷轧搪瓷钢的贮氢机理和氢渗透试验研究

分析了Ti-IF冷轧搪瓷钢的贮氢机理,通过3种不同成分钢板的氢渗透试验,研究化学成分、冷轧压下率、第二相粒子等对钢板贮氢性能的影响。结果表明,Ti、S含量较高的钢中第二相的体积分数也高,贮氢性能越好;冷轧压下率越高,钢板贮氢性能越好,相应的抗鳞爆性能越好。     

南钢N245RTC搪瓷钢的开发

介绍了搪玻璃专用中厚板和双面搪瓷用热轧卷板的开发试验,以Ti元素作为捕氢陷阱的形成元素,通过控制w(Ti)/w(C)比及析出粒子的数量,消除鳞爆现象,可以生产出搪瓷性能优异的双面搪瓷热轧钢板,取得了良好的效果。     

低成本冷轧搪瓷钢板的研制

研制了一种低成本冷轧搪瓷钢板,分析了该钢板的显微组织和力学性能,通过氢渗透法测试了钢板的抗鳞爆性能,采用静电干法工艺对钢板双面涂搪,测定了搪瓷板的密着性。结果表明,钢板组织为铁素体,晶粒度为7级,钢中形成了大量第二相粒子,包括短线状MnS夹杂、球状(或椭球状)含锰氧化物以及细小的硫化物析出相;钢板屈服强度低于190 MPa,伸长率超过42%,加工硬化指数和塑性应变比分别达到0.25和1.7以上,达到了冲压用钢DC03的力学性能指标要求;钢板氢渗透时间平均值为14.4 min/mm~2,涂搪后无鳞爆缺陷,搪瓷密着性为1级。     

冷轧搪瓷钢板的抗鳞爆性能的研究

研究了冷轧超低碳搪瓷钢板的抗鳞爆性能,该钢板具有优良的抗鳞爆性能,氢在钢板（厚度为１ｎｍ）中的穿透时间为１１．４ｍｉｎ,钢板中不可逆陷阱的贮氢容量为１２．６ｍｏｌ／ｍ＾３。     

AlN析出对DC01搪瓷用钢鳞爆性能的影响

为了研究AlN颗粒析出对DC01搪瓷用钢鳞爆性能的影响,通过对DC01搪瓷用钢采用不同卷取温度(580、610及640℃)控制退火成品第二相粒子AlN颗粒析出并采用模拟搪瓷试验对退火成品进行涂搪对比。结果表明,当卷取温度为580℃时,退火后析出相以Fe3C颗粒为主,平均尺寸约为500 nm;随着卷取温度升高到640℃,在钢板内形成大量、弥散分布的第二相粒子AlN颗粒,其平均尺寸为50 nm左右,从而形成了大量的贮氢陷阱,能有效提高钢板的贮氢性能,避免鳞爆缺陷产生。     

冷轧搪瓷钢的夹杂物与抗鳞爆性能

对比研究了冷轧搪瓷钢DC05EK和TC03的金相组织、夹杂物和氢渗透时间,结果表明:2种搪瓷钢的组织均为铁素体,与DC05EK钢相比,TC03钢晶粒细小,夹杂物种类多且颗粒尺寸分布范围宽。定量统计结果显示,TC03钢的夹杂物体积分数更大,氢渗透试验结果表明,TC03钢板抗鳞爆敏感性(TH)平均值比DC05EK高出约40%。钢中氢陷阱主要为晶界和夹杂物,其数量和作用大小的不同是导致2种钢板抗鳞爆性能差异的主要原因。     

冷轧超低碳搪瓷钢板的开发

简要介绍了冷轧超低碳搪瓷钢板的成分特点及工艺要求,分析了钢板的组织结构及析出相,研究了冷变形对氢在钢板中扩散系数和穿透时间的影响。实际批量生产结果表明,以及超低碳为基础、添加适量的合金元素,采用合适的工艺制度生产的冷钢板既具有优良的成形性能,又具有优良的抗鳞爆性能。     

搪瓷用钢鳞爆的研究

根据搪瓷用钢板鳞爆的起因,采用电化学方法测定了 TC 1、08F、08Al 等几种搪瓷用钢的氢扩散系数 D 值,并对应生产的实际情况得出鳞爆与扩散系数有良好的对应关系,即 D 值大的搪瓷用钢易发生鳞爆,D 值小的不易发生鳞爆。研究结果表明,钢材的延伸率、压下率、热处理制度及含钛钢的 Ti/C 值等均对扩散系数有着不同的影响规律,这些规律对研究含钛搪瓷用钢的生产和使用有重要意义。     

新型低碳冷轧搪瓷用钢的组织及性能

 在满足性能要求和少添加高价合金元素的前提下,以开发出高贮氢性能及可适应后期多元化涂搪工艺为目的,开发出一种含钛低碳冷轧搪瓷用钢。对搪瓷钢不同状态的组织和性能进行了研究,获得了第二相粒子的析出规律、涂搪前后的晶粒尺寸及析出物的变化规律及退火工艺对强度的影响规律。对钢板的氢渗透时间进行了测定,试验结果与随后的涂搪试验吻合。搪瓷用钢的室温组织为铁素体,涂搪后晶粒有一定程度的长大;钢板中弥散粗大的第二相粒子Ti4C2S2是提高钢板贮氢性能的主要因素。730℃保温5h退火后,氢渗透时间tb大于18min,氢扩散系数D小于0.44×10-6cm2/s;钢板与涂层具有良好的密着性,可承受110g钢球在2m高度自由落体的冲击。     

硫含量对极低屈服点钢组织与性能的影响

摘要：采用Gleeble 3800热模拟试验机、OM、TEM与Vickers 硬度计，研究了不同变形温度下S含量对极低屈服点钢析出相、晶粒尺寸与硬度的影响；结合拉伸和冲击试验考察了S含量对实验室试轧钢板力学性能的影响。结果表明，不同变形温度下，当S质量分数由0.0018%提高至0.0077%，钢中晶粒尺寸发生粗化，硬度降低，析出相的主要类型由TiC变为Ti4C2S2和TiS，析出粒子的尺寸随之增大，分布数量减小。S质量分数为0.0077%的试轧钢板较S质量分数为0.0018%的试轧钢板具有更低的屈服强度且塑韧性并未降低，其综合力学性能更优且完全满足极低屈服点钢的要求。     

08TiXt热轧叠轧薄板抗鳞爆性能的研究

采用电化学方法，自动记录强制鳞爆时间和测定氢在搪瓷用钢中的扩散行为，表明０８ＴｉＸ钢忆叠轧薄板的抗鳞爆性能远远超过搪瓷工业上常用的Ａ３和１０号钢，完全达到使用要求，通过测试也表明，热轧 钢材抗鳞爆性能高于热轧退火状态的钢材；随着热钢材热处理的升高，其抗鳞爆性能降低；提高钢村的Ｔｉ／（Ｃ＋Ｎ＋Ｓ）比值，可提高搪瓷用钢的抗鳞爆性能。     

Study on hydrogen induced delayed fracture of 1500 and 2000MPa hot stamping steels

The application of hot-stamping steel (HS) in the automobile is an inevitable trend, but the hydrogen embrittlement sensitivity of HS steel still needs to be studied and improved. The hydrogen diffusion behavior and hydrogen embrittlement sensitivity of 1500 and 2000MPa hot stamping steels were studied by means of hydrogen penetration, slow strain rate tensile (SSRT), and fracture analysis. The results show that the apparent diffusion coefficient Dap (1.71×10-7cm2/s) of 1500HS is significantly less than the Dap (3.45×10-7cm2/s) of 2000HS; delayed fracture resistance of 1500HS is superior to 2000HS. From the fracture analysis, under the same hydrogen charging conditions, the fracture morphology of 1500HS changed from typical dimple ductile fracture to quasi cleavage brittle fracture, while 2000HS changed from dimple morphology to intergranular brittle fracture with the increase of hydrogen charging current density. While the deformation degree of 2000HS was very small, the local hydrogen content and stress value had reached the critical deal. The hydrogen reduced the bonding force between grains, resulting in the nucleation and propagation of microcracks. Therefore, with the improvement of the strength of HS steel, Ti and V micro alloyed elements should be properly added to form nano precipitates, as irreversible hydrogen traps to capture hydrogen atoms, hinder their diffusion and segregation, and effectively refine the structure and pinning dislocations, to improve the resistance to hydrogen induced delayed fracture of HS steel.     

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The influence of heating temperature and holding time of different Ti content of microalloy high strength steel on austenite grain size and the influence of the precipitation characteristics on mechanical properties were quantificationally investigated through the methods of metallography, phase analysis and X-ray diffraction. The results show that, under the heating temperature of 1000-1150?? and the same soaking time,the steel B has small size of austenite grain. However when the temperature rises to 1150?? and above, austenite grain size in steel B increases fast, bulky containing Ti precipitates almost have no side effect on austenitic grain growth. With Ti content in steel increasing, MC precipitated phase in steel A and B respectively is 7. 5%, 159. 0% of the total M3C precipitated phase. When the ratio of MC/M3C increases, the corresponding strength of steel also increases. The mass fraction of less than 10nm precipitation phase in steel A and B is 2. 2% and 21. 7%.     

高Ti-Q550钢中Nb、Ti第二相的析出行为

 采用Thermo-Calc软件、热模拟及扫描电镜研究高Ti-Q550钢中微合金的析出规律。采用Thermo-Calc软件计算不同温度下Nb、Ti的析出规律,钛含量对钢中Nb、Ti析出规律及A3的影响。采用热模拟和扫描电镜研究钢中铌相的析出温度。计算结果表明,钛相的析出温度为1498℃,铌相析出温度为1251℃;随着钢中钛含量的增加,(Nb,Ti)C相析出温度和A3温度升高,但铌在钢中的固溶量降低;当钛的质量分数小于0. 08%时,Ti(N,C)相析出温度随钛含量增加而升高,但当钛的质量分数大于0. 08%时,相析出温度基本不变,钛在钢中的固溶量随钛含量增加而增加。     

冷轧超低碳搪瓷钢板的试验研究

研究了冷思超低碳搪瓷钢板的力学性能和贮的贮氢性能。研究结果表明,以超低碳为基础,添加适量的合金元素,采用合适的工艺制度生产的冷轧钢板既具有优良的成形性能,又具有优良的贮氢性能。其断裂伸长率达５２％。平均ｒ值达１．８,ｎ值达０．２５,氢渗透时间达到７．７ｍｉｎ,具有优良的抗鳞爆性能。     

加钛超低碳钢成形性能和贮氢性能的研究

研究了一种含硫、氮较高的加钛超低碳钢的力学性能和贮氢性能。试验结果表明,试验 材料在热轧时采用较高的终轧温度和冷轧时采用大的压下率并进行合适的模拟退火,既可以获得优良的成形性能,又可以获得优良的贮氢性能。其断裂伸长率达到５３％,平均ｒ值达１．８,ｎ值达０．２６,氢渗透时间超过１０ｍｉｎ,具有优良的贮氢性能和抗鳞爆性能。     

Investigation of titanium oxides as hydrogen traps in Ti‐IF steels for enamelling

Ti‐stabilised interstitial free (IF) steels designed for enamelling applications contain higher levels of C, N, S and Ti than conventional deep drawing IF steels, e.g. for automotive applications. Consequently they contain a sufficient amount of hydrogen traps, which are essential to avoid the formation of fish scale defects during enamelling. A large amount of precipitates is however known to have a detrimental effect on the mechanical properties. The possibility of adding Ti‐oxides as an alternative type of ‘precipitate’ and thus keeping the S and C‐content of the IF steel low, was investigated. The present paper reviews the results of the investigation of the microstructure, the mechanical and the enamelling properties of a Ti‐deoxidised laboratory cast IF steel with low C, N and S‐content. The composition, morphology and size distribution of the inclusions and precipitates were evaluated by scanning electron microscopy at all stages of the laboratory processing.