【作者】 张国强；

【导师】 孙俊生；

【作者基本信息】 山东大学 ， 材料加工工程， 2008， 硕士

【摘要】 机械零件大多数是用金属材料制造的,由于零件之间或零件与物料之间的相对运动,会发生磨损。随着现代工业的发展,机械零件经常处于异常复杂和苛刻的条件下工作,大量的机械装备往往因磨损而报废。堆焊因工艺简单、设备投资少、操作灵活、适应面广而被广泛应用于在钢板表面制备耐磨合金层,提高机械零件的寿命。焊条、药芯焊丝均为传统的堆焊材料,一般采用合金粉末生产。合金粉末生产工艺复杂,使得堆焊材料的成本大幅度提高。同时传统的手工堆焊工艺生产效率也较低。本文针对上述问题,设计了夹芯合金粉块、堆焊合金颗粒两种新型耐磨堆焊材料。夹芯合金粉块解决了手工堆焊效率低的问题,堆焊合金颗粒则以钢铁企业的自产废钢为主要原料,降低了生产成本。夹芯合金粉块由内部的焊芯和外部的药皮两部分组成,其横截面设计为三角形、半圆形、梯形等特定几何形状之一,很好地解决了合金粉块中合金元素较多、熔点较高不易熔敷的问题。采用油压式焊条压涂机压制,在合金粉块中添加H08A焊芯,保证了压涂的工艺性能。夹芯合金粉块可以采用电弧熔敷。本文根据装载机的磨损工况,设计了Cr-Mo-V系夹芯合金粉块,通过SEM、X射线衍射和电子探针等实验手段研究了Cr-Mo-V合金粉块堆焊金属的组织与性能。实验结果表明:Cr-Mo-V堆焊金属的组织以马氏体为主,Cr、Mo等合金元素主要以固溶体的形式存在于基体中。通过磨料磨损实验研究了Cr-Mo-V堆焊金属中Cr/C比、Mo含量变化、堆焊金属的硬度与耐磨性的关系。基于研究结果,进行了Cr-Mo-V夹芯合金粉块应用于装载机工作装置的工程试验,结果表明耐磨性良好。随着钢铁冶金行业装备水平的提高,高洁净钢材的产量逐年提高。在钢板生产过程中,由于定尺的需要大约产生钢产量4%～5%的板头、板边,目前钢铁企业多作为废钢回炉重新炼钢,使得这些废钢重走炼钢、轧钢工艺流程,浪费能源、污染环境。这些废钢所具备的洁净特点符合焊接材料用原料标准,并且其中所含有合金元素也可以为焊接冶金有效利用。本文以钢铁企业的自产废钢为原料,采用中频感应炉将废钢熔化成钢水,并根据堆焊材料的使用工况添加适量合金元素,采用离心雾化技术将钢水制成堆焊用的合金颗粒,合金颗粒为直径0.1mm～5mm的球形或椭球形。合金颗粒采用电弧熔敷于钢板表面,可获得具有耐磨合金层的复合钢板。本文设计了系列Fe-Cr-C系高铬铸铁耐磨堆焊合金颗粒,通过SEM、X射线衍射等实验手段研究了亚共晶、共晶及过共晶Fe-Cr-C系合金颗粒堆焊金属的组织性能。通过磨料磨损实验研究了Fe-Cr-C合金颗粒堆焊金属的耐磨性能,分析了堆焊金属的碳当量、硬度与耐磨性的关系,以及过共晶高铬铸铁堆焊金属中碳化物数量与耐磨性的关系。用Fe-Cr-C合金颗粒堆焊的耐磨复合钢板制作装载机河砂斗的耐磨部件,在山东大汶河采沙场进行了装机实验。结果表明,装载机河砂斗的耐磨性大大提高。更多还原

【Abstract】 Machinery accessory is mostly made of metal material.Due to the relative motion between machinery parts or between machinery parts and subject materials,the abrasion will take place.With the process of modern industry,working condition of machinery accessory is so extraordinarily demanding that lots of machinery accessory are discarded because of abrasion.As it is simple in technique and economic in equipment,facing welding is widely used in preparation of wear-resistant alloy layers on steel substrate to improve the lifespan of machinery accessory.The conventional surface welding materials,such as electrode and flux-cored wire, are commonly made from alloy powder.However,the production technology of alloy powder is complex,which increases cost of surface welding in turn.Furthermore,the production efficiency of traditional manual labour surface welding is relatively low.In concern of these problems,this paper designs two novel wear-resistant surface welding materials:core alloy powder agglomates and surface welding alloy beads.The using of Core alloy powder agglomates improves production efficiency of traditional manual labour surface welding,and,the using of weld alloy beads reduces the cost of production as we can recycle the home-grown scrap steel..Core alloy powder agglomates is maken up of core welding-wire in the center and coating in the outside.The cross section of core alloy powder agglomates can be designed to specific geometry form,such as triangle,hemicycle,echelon and so on, which solves the problem of high melting point and the difficulty in depositing,while too many alloy elements coexist in core alloy powder agglomates.Pressed by hydraulic electrode extrusion press,core alloy powder agglomates with H08A core welding-wire ensure quality of the extrusion.According to the wear wording condition of mechanical loader,this paper designs core alloy powder agglomates of Cr-Mo-V.The deposited metal of Cr-Mo-V alloy powder agglomates are studied using SEM,X-ray,electron probe etc.The results demonstrate that the majority of deposited metal of Cr-Mo-V mostly is martensite and alloy element,such as Cr,Mo presents in the substrate in the form of solid solution.The relationship between the fraction of Cr,C,and Mo in deposited metal,the hardness of deposited metal and wear-resistance are analyzed through grinding abrasion testing.Then,the project test of application of Cr-Mo-V alloy powder agglomates on work device of mechanical loader are carried out based on the research results.With the improving of equip level of ferrous metallurgy,the production of high purity steels increases rapidly.While the production high purity steels,the amount of coach and plate edges take up to the 4%～5%of gross steel production due to need of length fix,and these steels are seemed as scrap steel to melt down as scrap steel, which will experience the technological process of steel-making,and steel-rolling once again,causing the waste of energy source and the pollution of environment. However the purity of such scrap steel meets the standard of raw material of welding material,and alloy elements in it can be used by welding metallurgy efficiently.This paper makes use of the home-grown scrap steel of steel enterprise,melting the scrap steel into molten steel with medium frequency induction furnace,adding proper amount of alloy elements on the basis of application condition of surface welding material,and manufacturing the molten steel into weld alloy beads by centrifugal atomization.Alloy beads can be deposited on the surface of steel substrate by electric arc,obtaining clad plate with high wear-resistance alloy layer.The shape of the particle is globular shape or spheroidicity,and the dramatic of the particle is 0.1mm～5mm.This paper designs the chromium rich Fe-Cr-C cast-ion wear-resistant surface welding alloy beads.The structure property of Fe-Cr-C alloy particle high chromium cast-ion deposited metal of hypoeutectic,eutectic,hypereutectic are studied using SEM,X-ray,and so on.Through the test of grinding abrasion,the wear-resistant ability of deposited metal are measured,and the relationship between carbon equivalent in deposited metal,hardness of deposited metal,carbide quantity of hypereutectic high chromium cast-ion deposited metal and wear-resistant ability are analyzed.Wear resistant parts of basket of mechanical loader are fabricated by wear resistant clad plate of Fe-Cr-C alloy particle and tested in Taian battlefield.The results show that the wear resistant cladding greatly improves the abravability of basket of mechanical loader.更多还原