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铸248铸铁芯焊条是补焊铸铁的新型焊接材料,具有价格低廉、操作简便、效率高、焊缝组织与颜色接近母材、加工性能好等特点,它适用于大型铸铁件的补焊,尤其是机床制造业中焊后需要机械加工的部件。我厂几年来采用铸248焊条补焊了许多铸件,如床身、齿轮 相似文献
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一般铸铁件的焊接往往采用铸铁焊条。焊补汽缸体平面上缸筒之间的裂纹时面临着特殊的情况,该件不允许焊前预热,否则会引起变形以致报废,所以不能使用热焊及半热焊铸铁焊条,而一时冷焊铸铁焊条缺手。于是试用了不锈钢焊条,施焊时不必加热被焊件,注意选用较小电流,焊后立即用小锤敲击焊缝,同样保证了焊接质量。 相似文献
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铸铁件很多缺陷如气孔、砂眼、裂纹等,一般可以用焊补的方法加以修复。但在铸工车间中,如何获得便利而有效的焊补方法,便成为防止废品的重要措施之一。由于铸铁的特性和焊处冷却速率很快,用一般冷焊法往往容易发生白口,使加工困难。用其他冷焊方法,对于小型铸工车间也有其不便处,如用蒙内尔合金焊条冷焊虽能保证 相似文献
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目前,铸铁件冷焊多采用昂贵的镍基焊条.采用价格便宜的铸铁焊条冷焊,其焊缝强度低.塑性差、易出现裂纹、白口组织,特别是接头硬度高,加工性能差.为此,研制了一种新型同质铸铁冷焊焊条.这种焊条采用H08A焊芯,在冷焊状态下达到下述设计要求:①有效地解决裂纹、白口问题;②接头硬度低,机械加工性能好,焊缝强度高;③具有良好的工艺性能.铸铁冷焊焊条药皮中加入多种石墨化剂.复合变质剂及稀土、硅钙合金.为减少石墨化元素烧损,采用了弱氧化性的萤石-长石渣系.1 实验内容及结果分析实验采用φ4.0 mm焊条,交流施焊,焊前试板不预热,焊后的自然冷却,焊条焊前280℃×1h烘焙.试板为灰口铸铁.焊接电流160~170A,电弧电压25~30V,焊接速度150mm/min.焊缝的化学成分见下表.焊缝抗拉强度315MPa.硬度试验结果: 相似文献
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Hollow cast-iron bars with an outer diameter of 60-300 mm, a wall thickness of 7-40 mm and a length of 10 m or longer were produced massively by vertically continuous casting. The whole casting processes were analogous to the casting processes of solid bars by horizontal continuous casting. The metallographic microstructure, the distribution of chemical composition along their radius direction and the mechanical properties of the hollow bars were investigated. The results show that the hollow cast-iron bars are compact and few shrinkage cavities and shrinkage porosities exist in them. Their graphite grains or their eutectic colonies are very fine and their mechanical properties are superior to that of bars produced by sand casting. Their chemical composition is distributed uniformly along their radius direction and no segregation was observed. 相似文献
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硬质合金具有硬度高、强度好、耐腐蚀和耐磨损的特点,采用传统方法难以满足精密及超精密加工的技术要求.本文采用不同粒度的铸铁结合剂金刚石砂轮ELID镜面磨削硬质合金,得到了不同加工效率以及不同加工表面质量的硬质合金磨削效果,揭示了不同粒度砂轮其磨削性能变化的规律与作用.实验结果表明:在相同的进给量下,粗粒度砂轮的磨削效率较高,能更好地控制工件的尺寸精度.细粒度砂轮则磨削效率较低,但能获得优良的加工表面质量.砂轮表面的氧化膜在磨削过程中扮演非常重要的角色,磨粒的粒径与砂轮表面氧化膜厚度的比值大小决定了砂轮的磨削性能.氧化膜的形成又受到电解参数的影响,可以通过对电解参数的调节实现高效率高精度的ELID磨削. 相似文献
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采用自制铜铁焊条、镍铜焊条,运用电弧冷焊工艺对灰铸铁进行焊接试验,研究了其焊后接头的金相组织、硬度。结果表明,用所研制铜铁焊条、镍铜焊条进行铸铁补焊是可行的。 相似文献
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A. G. Anisovich I. N. Rumyantseva P. N. Misuno V. F. Bevza V. V. Azharonok 《Surface Engineering and Applied Electrochemistry》2010,46(2):100-107
The variation in the structure and properties of cast-iron sealing rings (content in wt %: 2.8–3.0 Si; 0.4–0.6 Mn; 0.1–0.2
Cr; 0.5–0.6 Ni; 0.7–0.9 Cu; 0.04–0.06 Mg; 2.8–3.0 C) under their exposure to a 5.28-MHz pulsed magnetic field is studied.
Variations in the eutectoid morphology, the internal structure of the graphite inclusions, and the size of the free cementite
inclusions, which result in the enhancement of the hardness, are observed. The magnetic-pulse treatment of rings induces compression
stresses in them. The physicomechanical properties of the rings change periodically upon the variation of the number of treatment
cycles. The optimum mode corresponds to two cycles. 相似文献
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Investigations were carried out into the behaviour in a corrosive medium of joints in galvanized steels produced by arc welding and brazing without removal of the coating using welding materials based on iron, copper, zinc and aluminium. The topography of the electrode potentials and galvanic currents on the surface of the joints, coated with a thin layer of the electrolyte, is determined. The maximum width of the damaged coating in relation to the joint, ensuring efficient anodic shielding, is determined. The corrosion resistance of the joints is evaluated. 相似文献
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将耦合电弧钨极和GPCA焊方法结合,形成了耦合电弧钨极GPCA-TIG焊方法,该方法可实现深熔深高速度焊接.对比分析了在较高焊接速度时常规TIG焊、耦合电弧钨极TIG焊和耦合电弧钨极GPCA-TIG焊的焊缝表面成形和截面形貌,发现耦合电弧钨极GPCA-TIG焊可避免咬边和驼峰焊道的产生,并且焊缝熔深有所增加.耦合电弧钨极GPCA-TIG焊工艺试验表明,焊缝熔深和熔宽随焊接速度的减小和外喷嘴位置的升高而增大,随着弧长和外层氧气流量的增加先增加后略有减小;随着焊接速度的减小,弧长和外层氧气流量的增大,焊缝咬边减轻,外喷嘴相对高度变化时焊缝均未出现咬边. 相似文献
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铸铁焊补特殊工艺研究与应用实践 总被引:1,自引:0,他引:1
在生产实际中常常会遇到铸铁件的焊接修复.冷焊工艺由于焊前不预热、劳动条件好、成本低、周期短等优点,已成为铸件焊补的首选工艺.在实践中发现,仅采用普通的冷焊工艺,其产生白口、淬硬组织和应力的倾向比热焊大,很难获得满意的焊补质量,若在焊补中采取一些特殊的工艺措施,能收到较好的效果.详细分析了自制铜钢焊条焊补法、水浸焊补法、... 相似文献
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