共查询到20条相似文献,搜索用时 125 毫秒
1.
2.
3.
4.
5.
6.
7.
蠕墨铸铁的起源、发展及其熔炼工艺 总被引:2,自引:2,他引:0
介绍了蠕墨铸铁的起源、发展、性能指标及石墨形态.按照蠕化剂的发展过程阐述镁系和稀土系蠕化剂的化学成分和加入量.简要介绍蠕墨铸铁化学成分的选择,各种预处理、蠕化处理和热处理工艺,并列举了蠕墨铸铁的应用实例,认为蠕墨铸铁将有巨大的工程应用空间. 相似文献
8.
9.
蠕墨铸铁——现代柴油发动机缸体和缸盖的材料 总被引:5,自引:1,他引:4
在不增加发动机尺寸和重量的前提下,为满足使用寿命的要求,油发动机缸体和缸盖的材料将要由普通的灰口铁转向蠕墨铸铁.蠕墨铸铁的抗拉强度和刚度分别高于普通灰口铁的75%和45%,疲劳强度几乎是普通灰口铁的2倍.因此,用蠕墨铸铁缸体和缸盖所制造的柴油发动机不仅满足了使用寿命的要求,同时尺寸也稳定,在整个使用寿命内满足尾气质量的要求.由于欧4标准的要求,在欧洲,已有9种新设计的蠕墨铸铁缸体和缸盖的重型柴油发动机在2007年启动.预计,欧4标准将在2009年引入中国的主要城市.中国的铸造业在2010年末前将会经历一个很大的转向到研发重型柴油发动机的蠕墨铸铁缸体和缸盖,然后,很快地进入批量生产.同时还要出口到国际市场. 相似文献
10.
11.
12.
13.
In general,during the production of compacted graphite iron (CGI),the active residual magnesium reduces and the effect of inoculation fades after magnesium treatment.In this paper,characteristics of the thermal analysis curve of CGI are compared with those of ductile iron and grey cast iron.The fading effect on the compacted graphite percentage and thermal analysis curve were also studied.Results indicate that the undercooling of CGI is as low as that of ductile iron,but CGI shows evident recalescence.In fading process,the magnesium element acts with oxygen.For a decrease in magnesium content,both the compacted graphite percentage and the austenitic liquidus temperature increase.The temperature of eutectic undercooling (TEu) decreases before the flake graphite appears.After that,TEu increases quickly,up to as high as 20 ℃,and then gradually decreases.The evolution of recalescence degree is opposite to that of TEU. 相似文献
14.
再探蠕虫状石墨的形成机理 总被引:1,自引:0,他引:1
通过对不同冷速下结晶蠕铁的液淬试样进行分析观测,对蠕墨铸铁的一次结晶及蠕墨的形成机理进行了一些探讨,并进一步阐述了石墨中倾斜孪晶的作用。 相似文献
16.
目的准确预测蠕墨铸铁加工过程中的表面质量,指导加工参数调整,保证加工过程中加工质量的稳定,运用差分进化算法优化的SVM模型(DE-SVM)构建蠕墨铸铁表面粗糙度(Ra)预测模型和加工参数选择方法。方法采用DE-SVM提高支持向量机回归模型的预测精度,建立针对实际加工材料的表面粗糙度预测模型,基于构建的预测模型,挖掘表面粗糙度与加工参数之间的关系,从而获得较优的加工参数。结果结合蠕墨铸铁的铣削加工实验数据,对比DE-SVM与常用优化算法(粒子群优化算法(PSO)和遗传算法(GA))优化的SVM模型,DE-SVM模型获得的MAPE(0.122)和R2(0.9559)值均优于粒子群和遗传算法优化的支持向量模型获得MAPE和R2值。在给定的加工参数范围内,切削速度和进给速度对表面粗糙度的影响较大,且表面粗糙度与切削速度成正比关系,与进给速度成反比,而切削深度对表面粗糙度影响不显著。结论由实验的对比结果可知,采用DE-SVM模型建立的蠕墨铸铁表面粗糙度模型具有更高的预测精度,基于DE-SVM获得的加工参数对表面粗糙度的影响,可有效指导加工参数的选择与调整,对保持蠕墨铸铁优良的加工质量具有较好的指导意义。 相似文献
17.
含磷蠕墨铸铁闸瓦的研制 总被引:1,自引:0,他引:1
本文研制了一种新型材质的闸瓦—含磷蠕墨铸铁闸瓦。试验结果证明,一定量的磷加入蠕墨铸铁中,其硬度、抗拉强度均满足闸瓦的使用要求而耐磨性可达到中磷灰铸铁闸瓦的2倍以上。磷加入蠕墨铸铁中使得蠕墨铸铁的磷共晶数量增加而石墨数量减小,因此使得其强度降低,硬度升高,闸瓦的耐磨性提高。 相似文献
18.
19.
本文对Si-Mo、Cr-Mo耐热铸铁的导热率和热扩散率及其影响因素作了测试和分析。结果表明:灰铁的导热性能最好,蠕铁次之,球铁最差;蠕化率越高,导热率越好;铁素体的导热性能优于珠光体。 相似文献
20.
While the manufacture of compacted graphite (CG) iron castings has seen significant expansion over the recent years, the growth of CG during iron solidification is still not fully understood. In this work, effort was expanded to experimentally reveal the evolution of graphite shape during early solidification and its relationship to the solid fraction. To this purpose, interrupted solidification experiments were carried out on hypereutectic irons with three magnesium levels. The graphite shape factors were measured and analysed as a function of chemical composition and solid fraction. Scanning electron microscopy was carried out to establish the fraction of solid at which the transition from spheroidal graphite (SG) to CG occurs. It was confirmed that solidification started with the development of SG for all CG irons. The SG-to-CG transition was considered to occur when the SG developed a tail (tadpole graphite). The findings were integrated in previous knowledge to attempt an understanding of the solidification of CG iron. 相似文献