共查询到18条相似文献,搜索用时 146 毫秒
1.
2.
湖南华菱涟源钢铁有限公司在其原用于生产建筑板及低档家电板的镀锌线上开发了EDDQ产品,但冲压作业中出现了冲压开裂问题。为此,分析了现有镀锌线的生产工艺、冲压润滑工艺和钢中夹杂物等,通过采取将镀锌退火温度控制为850 ℃、给定合理的冲压涂油量、确保模具间隙与材料厚度匹配等措施,实现了DX53D+Z、DX56D+Z系列产品无冲压开裂的批量生产。 相似文献
3.
4.
5.
对HP 295拉延月牙开裂缺陷样品进行失效分析,探讨缺陷的形成原因。结果表明:月牙开裂缺陷的形成主要与冲压拉延的应力状态、材料中的沿轧制方向分布较多细长MnS夹杂有关,中心偏析、较明显的带状组织进一步促进了月牙开裂缺陷的形成。 相似文献
6.
7.
8.
9.
10.
11.
The nonmetallic inclusions in low‐alloy pressure vessel steel A533B were carefully examined and the low cycle fatigue (LCF) behavior of the steel was investigated in 288°C air and water. Much attention was paid to the roles of inclusions on fatigue crack initiation and propagation in high temperature water. Three types of inclusions were observed in the steel, consisting of isolated or clustered sulfide inclusions, duplex oxide‐sulfide inclusions and isolated oxide inclusions. In high temperature air, fatigue cracks initiated predominantly from subsurface inclusions. In high temperature water, however, fatigue cracks initiated primarily at corrosion pits on the specimen surfaces resulted mainly from the dissolution of large or clustered sulfide inclusions. The subsurface and bulk inclusions also contributed to the fatigue cracking in high temperature water. Possible influence of the above three types of inclusions on environmentally assisted cracking (EAC) was evaluated. The fatigue fractographic features suggested a synergism between sulfide inclusions and hydrogen‐induced cracking dominate the present EAC in high temperature water. 相似文献
12.
13.
14.
Su-Il Pyun 《工业材料与腐蚀》1991,42(11):592-597
The present work is concerned with the role of sulphidic inclusions in hydrogen-assisted cracking of low-alloy steels with different sulphur contents. The steels were previously cathodically charged in sulphuric acid solution. Evaluating the susceptibility to hydrogen-assisted cracking in terms of the reduction in area values, the high sulphur steel is less susceptible than the low sulphur steel. The fracture surface of the low sulphur steel appears rather brittle, with local quasi-cleavage fractures around large intergranular fracture facets. In contrast, the fracture surface of the high sulphur steel is characterized predominantly by the microvoid coalescence mode, with a great number of manganese sulphide inclusions. The difference between the two sulphur steels is based upon the concept that the interfaces between sulphidic inclusions and matrix act as trapping sites for hydrogen and thus hydrogen is uniformly distributed over the sulphidic inclusions. 相似文献
15.
对40Cr圆钢表面开裂试样进行分析,发现圆钢裂纹处金相组织正常,开裂不是由于夹杂物及不良组织造成,表面划伤是造成圆钢表面裂纹的主要原因。可以通过加强导卫及辊道的检查等措施,消除表面裂纹的发生。 相似文献
16.
在高铬不锈钢的生产中,影响质量最严重的是钢锭中的轴心裂纹和钢材中的髪纹。本文的研究结果指出,这两种缺陷属于同一来源,没有轴心裂纹的钢锭在锻成钢材后也没有髪纹。 钢锭中轴心裂纹是在凝固过程中形成的,因而冷凝条件对它有影响。利用耐火材料做锭模可以得到内部坚实的钢锭,减小锭模模壁厚度,增大钢锭圆锥度或降低浇铸温度等只能减轻而不能完全消除裂纹。 熔炼过程中的脱氧方法对钢中夹杂物的性质和形状分布有影响。改善脱氧方法并采用薄模浇铸,可以大大地减少轴心裂纹和髪纹,从而提高钢的收得率。我们认为夹杂物的性质、多寡及其形状分布可能对钢液的流动性和表面张力有影响;改善钢液的流动性或减小其表面张力可以促进钢液的充填性能,从而弥补凝固过程中由于冷凝收缩而产生的缺陷。 在一定压力以下的真空中熔化和浇铸可以得到内部良好的钢锭。通过真空熔铸所得到的钢锭,其柱状晶区大小缩小,而柱状晶的缩小对避免钢锭中轴心裂纹有利。得到这种效果的原因可能是多方面的,真空有去气作用,在真空中钢锭的凝固散热与在一般情况下有所不同,真空作用使钢液的性质发生变化等等。虽然,上述几方面的理论基础还有待于进一步研究,但从目前实际效果来说,真空熔化和浇铸应该认为是提高不 相似文献
17.