【作者】 任志远；

【导师】 王从曾； 苏学宽；

【作者基本信息】 北京工业大学 ， 材料学， 2001， 硕士

【摘要】 采用双层辉光离子渗金属技术，对不同含碳量的试样表面进行W、Mo、Ti三元共渗，使试样表面形成类似高速钢合金成分的等离子合金化层（简称“渗层”或“渗金属层”）。渗金属层可获得合金铁素体，合金珠光体和白亮层三种不同类型的渗层组织。在不同工艺参数和源极成分配比下，通过对试样渗金属层的显微组织、合金元素含量进行分析和研究，发现含钛表面高速钢渗层的厚度和合金元素浓度与工艺参数、源极成分配比密切相关，并得出以下结论：合金元素成分（C）和渗层厚度（Ld）随着源极电压的提高而增加；C和Ld随着阴极电压的提高呈∧型，最佳值在400～500V间；C和Ld随着气压的提高也呈∧型，最佳值在40～70帕；C和Ld随着极间距的增大而减少，控制在15～20mm之间为最佳；C和Ld随着温度的升高而增加，渗层厚度与加热温度呈指数关系，与保温时间呈抛物线关系，类似于化学热处理；C和Ld随着基体含碳量的提高而迅速降低；增加源极成份配比中Ti的比例，可以提高渗层中钛元素的浓度；无论采取何种工艺参数和钢种，渗层的显微硬度总比基体的显微硬度高。在本试验中，利用现有实验设备的条件和检测手段，采用下列工艺参数值：源极电压（Vs）1000V；阴极电压（Vc）400V；气压（p）70帕；极间距（d）20mm；加热温度（T）1100℃；保温时间（τ）5h。试样名称，纯铁或20钢；源极成分配比，含Ti30％、50％（W、Mo各占其余量的50％）、100％。 再把最佳工艺参数和源极成分配比下的双辉渗试样经渗碳，淬、回火，制成一种新型的高速钢——含钛表面高速 北京工业大学硕士学位论文 摘 要 钢。试验结果表明，渗碳后渗金属层的显微组织是合金珠 光体十合金碳化物，而且合金碳化物的分布与普通冶铸高速 钢相比更为细小、弥散、均匀；利用X射线衍射微区分“析， 测得第二相分别为 MsC（Fe。C）、M。C（Fe。W＊）不 MC（TI、 Y－MOC、WC）型碳化物；对于不同源极配比和不同钢种的渗 金属渗碳试样，其渗层显微硬度比基体显微硬度高。淬、 回火后含钛表面高速钢的显微组织为回火马氏体和其上分 布着的均匀细小的粒状碳化物。其碳化物比普通冶铸高速 钢细小均匀得多；利用X射线衍射微区分析，测得第二相 分别为 M。C（Fe。W。C）、M，C。［（FeWMo），C。」禾 MC（TI、Y－MoC） 型碳化物；硬度为 760－890 HV。；，相当于 62－69HRC，心部 硬度 510 HV。；，相当于 50HRC。达到 了表层具有高硬度、 高耐磨性，而心部则具有足够的硬度和良好的弹性及韧性 的要求。红硬性仍可达 760HV0．；左右，相当于 62HRC。与 普通高速钢相比，其硬度、耐磨性及红硬性都有所提高。更多还原

【Abstract】 By using the technique of Double-glow Plasma Surface Alloying (DGPSA) W , Mo and Ti are solute together into the surface of different carbon-content steels The alloying layer like the composition of High Speed Steel is formed on the surface of materials .There are three kinds of microstructure in the alloying layer which are alloying ferrite , alloying pearlite and white-light layer In the experiment , by analysing and studying the microstructure , the carbon-content of substrate , the thickness of the alloying layer in different processing parameter and different composition proportion of the source-electrode , the best processing parameters , carbon-content of the material and composition proportion of the source-electrode are found and some conclusions are reached that C(alloying element concentration) and Ld(alloying layer thickness) increase along with increasing of heat temperature , heat preservation time and source electrode voltage ; C and Ld have a A outline along with increasing of air-pressure and cathode voltage ; C and Ld decrease accompanied by increasing of substrate carbon-content; whatever processing parameters and steel III abstract type , micro-hardness of alloying layer is always higher than that of substrate parts . According to the ability of our experiment equipment and detection method ,the best processing parameters of the experiment as follows source electrode voltage ( Vs) I000V cathode voltage (Vc)400V ; atmospheric pressure (P)7OPa; distance of the two electrode(d)2Omm ; heating temperature(T) 11000C ; heat preservation time ( r ) 5h .The name of the sample , pure iron or 20 steel ; composition of source electrode Ti 30% , 50%( W,Mo are 50 percent of the rest ) and 100%. And then the workpiece is hardened and tempered , a kind of new type high speed steel 搒urface High Speed Steel containing Ti is formed .The results of the experiment show that the micro-structure of this new type surface high speed steel are composed of the tempering martensite in the alloying layer and even tiny grain-like carbide . By comparison with common high speed steel , the carbide is more uniform and smaller ; the second phases are M6C ( Fe3W3C ) . M7C3[ (FeWMo)7C3]and MC(TiC. y -M0C) carbide through the method of X-ray diffraction analysis ; the hardness of the alloying layer is 760?90 HV0 which is equal to 62~-69HRC ,and the hardness of core is 510 HV01 which is equal to 5OHRC ,this meets the needs of high hardness in the surface layer and the enough hardness good elasticity in the core of material .The high temperature hardness of the alloying layer is about 760HV01 which is equal to 62HRC . By comparison with common high speed steel , the hardness , wear- resisting ability and the high temperature hardness of it are higher更多还原