共查询到20条相似文献,搜索用时 93 毫秒
1.
离心铸造复合辊套用高铬铸铁的组织及性能研究 总被引:1,自引:0,他引:1
根据复合辊套的生产和使用要求,研究了3种成分的高铬铸铁通过金属型铸造后的组织和性能。结果表明,金属型铸造的Cr20高铬铸铁其铸态组织由枝晶奥氏体、共晶奥氏体和共晶碳化物组成;具有较好的韧性,并且有一定的耐蚀性和良好的耐磨性;铸态硬度达到HRC55左右。Cr20高铬铸铁能满足轧辊的生产和湿摩擦条件下的使用要求。 相似文献
2.
离心铸造气门座圈用高铬铸铁的组织及性能研究 总被引:2,自引:1,他引:1
根据气门座圈的生产和使用要求,研究了一种成分的离心铸造高铬铸铁铸态和回火态的组织和性能。结果表明,离心铸造的高铬铸铁其铸态组织由初生奥氏体、共晶奥氏体和共晶碳化物组成,回火态组织由回火马氏体、残余奥氏体和共晶碳化物组成;热处理后的高铬铸铁消除了内应力,减小了晶格畸变,具有较好的强度,并且有一定的硬度。离心铸造高铬铸铁气门座圈能满足大功率内燃机的使用要求。 相似文献
3.
4.
5.
6.
采用了光学显微镜、扫描电镜、X射线衍射仪、洛氏硬度计等仪器,研究了离心铸造高铬铸铁轧辊铸态及淬火与回火后的显微组织结构、碳化物和硬度等。结果表明:高铬铸铁轧铸态组织主要是由奥氏体+少量马氏体+(Cr,Fe)7C3碳化物组成,碳化物呈粗大板条状或块状,不同温度热处理后,得到回火马氏体+(Cr,Fe)7C3+Cr7C3碳化物的组织,组织中粗大板条状碳化物消失,得到细小块状或椭圆状碳化物。该高铬铸铁轧辊铸态硬度为56.0HRC左右,在950℃淬火及400℃回火处理后硬度增加到了约65.5HRC。 相似文献
7.
8.
铸态合金耐磨铸铁适用于大型或复杂结构耐磨件。通过金相组织观察、X射线衍射相结构分析、图像分析仪定量金相测试和力学性能检测,研究了含钨量对铸态290Cr26MoW耐磨铸铁组织、结构和硬度的影响规律。结果表明,在含0~2.79%W的范围内,随着含W量的增加,铸态290Cr26MoW耐磨白口铸铁的初生基体数量减少,共晶团数量增加,共晶碳化物数量增加;铸态290Cr26MoW耐磨白口铸铁的碳化物结构类型没有改变,M7C3型碳化物为共晶碳化物;铸态290Cr26MoW耐磨白口铸铁基体的奥氏体比例增加,马氏体减少。马氏体多位于共晶团,即共晶碳化物周围。铸态290Cr26MoW耐磨白口铸铁的硬度由共晶碳化物数量和硬度以及基体中奥氏体和马氏体数量比共同决定。 相似文献
9.
采用金相试验、X射线衍射、硬度测试和磨料磨损试验研究了不含铌和含0.5、1.0%Nb(质量分数)的Cr20过共晶高铬铸铁的铸态组织和性能。结果表明,添加Nb元素能有效细化Cr20过共晶高铬铸铁的铸态组织,随着铌含量的增加,初生碳化物M_7C_3从粗大的杆条状转变细小、弥散分布的多边形块状,共晶碳化物从细长条状转变为弥散分布的点状。添加铌的Cr20过共晶高铬铸铁的硬度并未明显提高,含铌量为1.0%的Cr20过共晶高铬铸铁的硬度比不含铌的仅提高了约6%。然而,铌的加入显著地提高了Cr20过共晶高铬铸铁的耐磨性,含Nb量为1.0%的Cr20过共晶高铬铸铁的磨损量比不含Nb的减少了约21%。 相似文献
10.
回火工艺对高铬铸铁组织和性能的影响 总被引:5,自引:1,他引:5
应用铸态快冷技术获得奥氏体高铬铸铁,研究了回火工艺对其显微组织、力学性能和耐磨性的影响。结果表明,回火温度高于400℃时,奥氏体基体上开始析出细微的二次碳化物;525℃时,奥氏体转变为α+M23C5型混合组织,此时高铬奥氏体铸铁具有优异的综合力学性能和耐磨性。 相似文献
11.
The as-cast microstructures of high carbon high speed steels (HC-HSS) made by sand casting,centrifugal casting and electromagnetic centrifugal casting, respectively, were studied by using of optical microscopy (OM) and D/max2200pc X-ray diffraction. The results show that the microstructure of as-cast HCHSS is dominated by alloy carbides (W2C, VC, Cr7C3), martensite and austenite. The centrifugal casting and electromagnetic centrifugal casting apparently improve the solidification structure of HC-HSS. With the increase of magnetic intensity (B), the volume fraction of austenite in the HC-HSS solidification structure increases significantly while the eutectic ledeburite decreases. Moreover, the secondary carbides precipitated from the austenite are finer with more homogeneous distribution in the electromagnetic centrifugal castings. It has also been found that the lath of eutectic carbide in ledeburite becomes finer and carbide phase spacing in eutectic ledeburite increases along with the higher magnetic field strength. 相似文献
12.
The present work investigated the solidification microstructure of AISI M2 high speed steel manufactured by different casting technologies,namely iron mould casting and continuous casting.The results revealed that the as-cast structure of the steel was composed of the iron matrix and the M2C eutectic carbide networks,which were greatly refined in the ingot made by continuous casting process,compared with that by the iron mould casting process.M2C eutectic carbides presented variation in their morphologies and growth characteristics in the ingots by both casting methods.In the ingot by iron mould casting,they have a plate-like morphology and grow anisotropically.However,in the ingot made by continuous casting,the carbides evolved into the fiber-like shape that exhibited little characteristics of anisotropic growth.It was noticed that the fiber-like M2C was much easier to decompose and spheroidize after heated,as a result,the carbides refined remarkably,compared with the case of plate-like carbides in the iron mould casting ingot. 相似文献
13.
14.
15.
16.
采用离心铸造工艺制备了以废弃的轴承钢GCr15为基体,WC颗粒为硬质相的WC/钢复合材料.用金相观察和X射线衍射等分析方法,对该材料的显微组织进行了研究.结果表明:离心铸造WC/钢复合材料的显微组织是由莱氏体(P+Fe_3C_Ⅱ(共晶))、一次渗碳体(Fe_3C_Ⅰ)、二次渗碳体(Fe_3C_Ⅱ)、合金渗碳体((Fe,M)_3C)等碳化物及粒状珠光体组成,且其中有大量细小的WC、W_2C、再结晶W-Fe-C颗粒以及M_6C、M_7C_3、M_(23)C_6等碳化物颗粒析出;碳化物的形态较多,主要有网状、鱼骨状、树枝状和条块状. 相似文献
17.
18.
采用离心铸造法获得了WC颗粒增强钢基复合材料环形件,其复合层厚度为15~18mm。分析表明:复合材料层的组织由大量的骨状的复式碳化物和针状马氏体基体组成;复合材料层中增强颗粒被高温钢液全部溶化,原位析出含W,Fe,Cr,Mo复式碳化物;基体合金被溶解的增强颗粒不同程度的合金化,复合层从外至内韧性升高、硬度降低,但梯度不大。 相似文献
19.
Xiaoyu Huang Changming LiuXunjia Lv Guanghui LiuFuqiang Li 《Journal of Materials Processing Technology》2011,211(9):1540-1546
Hypereutectic Al-Si alloy-based composite pistons reinforced with SiC particles locally at the head were fabricated by centrifugal casting. The effects of various technique parameters, i.e., the slurry temperature of the alloy, the mold temperature and the rotation speed of the mold, on the particle segregation were investigated, and the macromorphologies and microstructures of pistons were observed. The mechanical properties, such as hardness and wear resistance along the axis of the piston and the thermal expansion coefficient at the piston head, were measured. The results showed that, (1) centrifugal casting can be used as a new and effective method in manufacturing pistons, and reasonable parameters were 850 °C, 600 °C and 800 rpm for the slurry temperature of the alloy, the mold temperature and the rotation speed of the mold, respectively; (2) the hardness values of pistons fabricated by centrifugal casting gradually increased from the piston skirt to the piston head, and the average hardness value in piston heads was improved by 23.7HRB over that of pistons fabricated by gravity permanent mold casting; (3) the piston heads showed excellent wear resistance, and the wear rate of piston heads decreased by 70.3% over that of the piston fabricated by gravity permanent mold casting; and (4) the average linear expansion coefficient of the piston head was 15.3 × 10−6 K−1 and decreased by 23.1% over that of pistons fabricated by gravity permanent mold casting. 相似文献