活塞销工作面激光合金化工艺及装置研究

发布时间：2019-01-26 20:27

【摘要】：采用Nd:YAG激光器对活塞销工作面进行激光合金化处理,以提高其表面硬度和耐磨性能。通过对活塞销工作面激光合金化的实验研究及理论分析,进一步优化工艺参数,提高合金化质量。具体研究内容如下:(1)主要从激光的加工方法、合金化材料的选择、合金化材料的添加方式、基体材料表面的预处理以及激光扫描路径规划五个方面,对活塞销工作面激光合金化的工艺进行制定。(2)为方便对活塞销进行激光表面合金化处理,获得较好的表面质量,根据活塞销的尺寸以及结构特点,设计活塞销的专用夹具对其进行装夹,并利用静电吸附的原理设计合金化粉末的预涂装置,提高了加工效率。(3)通过单因素实验得出脉冲工作电流、扫描速度、脉冲宽度、脉冲频率和离焦量对合金层质量的影响规律,选择脉冲工作电流、扫描速度和离焦量三个因素进行正交试验,得出最佳工艺参数组合为:脉冲工作电流I=150A,扫描速度V=160mm/min,离焦量L=12mm,脉冲宽度ti=0.8ms,脉冲频率f=100Hz,并建立了基于活塞销工作面硬度以及合金化厚度的数学模型。(4)在最佳工艺参数组合下,通过X射线衍射分析发现合金层的物相主要由马氏体、Fe-Ni固溶体、Ni-Cr-Fe固溶体、Cr_(23)C_6、Cr B、Ni_2Si等,其对合金层表面强化起着重要作用。(5)在最佳工艺参数组合下,用销环式磨损试验机对活塞销激光合金化处理的部分进行耐磨性实验,结果表明激光合金化处理20Cr钢活塞销的耐磨性比未处理前的增强了4.3倍。通过扫描电子显微镜观察,活塞销工作面经合金化处理以后,磨损面较为光滑,没有出现明显的剥落和犁沟现象,耐磨性得到较大的提高。
[Abstract]:The surface hardness and wear resistance of piston pin face were improved by laser alloying with Nd:YAG laser. Through the experimental study and theoretical analysis of laser alloying in piston pin working face, the technological parameters are further optimized and the alloying quality is improved. The specific research contents are as follows: (1) mainly from the laser processing method, the alloying material choice, the alloying material addition way, the matrix material surface pretreatment and the laser scanning path planning five aspects, The technology of laser alloying of piston pin working face is made. (2) in order to facilitate laser surface alloying treatment of piston pin and obtain better surface quality, according to the size and structure characteristics of piston pin, The special clamp of piston pin is designed to install it, and the precoating device of alloyed powder is designed by the principle of electrostatic adsorption, which improves the processing efficiency. (3) the pulse working current, scanning speed and pulse width are obtained by single factor experiment. The effect of pulse frequency and defocus on the quality of alloy layer was studied. The orthogonal experiments were carried out by selecting three factors: pulse working current, scanning speed and defocusing amount. The optimum process parameters were obtained as follows: pulse working current I ~ (150) A, scanning speed V ~ (160 mm / min), scanning speed (V) 160 mm / min. A mathematical model based on hardness and alloying thickness of piston pin face is established, which is based on 12mm defocus and pulse width ti=0.8ms, pulse frequency f100 Hz. (4) under the optimum technological parameters, X-ray diffraction analysis shows that the phases of the alloy layer are mainly martensite, Fe-Ni solid solution, Ni-Cr-Fe solid solution, Cr_ (23) C _ (6) Cr BJ _ (2) Si, etc. It plays an important role in strengthening the surface of the alloy layer. (5) the wear resistance of the parts of the piston pin treated by laser alloying is tested with the pin ring wear tester under the best technological parameters. The results show that the wear resistance of 20Cr steel Piston pin treated by laser alloying is 4.3 times higher than that of untreated Piston pin. By scanning electron microscope, the wear surface of piston pin face is smooth after alloying, no obvious flaking and ploughing, and the wear resistance is improved greatly.
【学位授予单位】：青岛理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG665

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