摘要
在800℃粉末法渗硼过程中对中碳45钢试样和渗剂施加交流电场,研究电场频率对粉末法渗硼的影响规律和作用机制。对渗硼保温过程中试样的温度、渗硼层显微组织、相结构、厚度及显微硬度分布等进行观测分析。结果表明:交流电场使试样温度高于渗硼保温炉温,电场电流恒定时,随频率从20Hz增至400Hz,试样温升先降低后升高,硼化物层及增碳区厚度均先减小后增加;当电场电流为3A时,硼化物层为单相Fe2B;当电场电流≤2A时,随频率增加,硼化物层由FeB+Fe2B双相变为单相Fe2B,渗层表层硬度降低、硬度分布曲线趋于平缓。分析认为,电场频率通过综合影响渗剂反应、活性硼原子及含硼活性基团在试样表面的吸附和试样内原子的扩散来影响渗硼。
An alternating current field （ACF） was applied to samples and media during pack boriding on medium carbon 45 steel at 800 ℃. The effects and working mechanism of the A.C frequency on the boriding were studied. The temperature of the samples during the soaking of the boriding, boriding cases＇ microstructure, phases, thickness and micro-hardness distribution were investigated. The results show that the ACF makes the temperature of the boriding sample higher than that of the furnace during soaking. With the increase of the frequency from 20 Hz to 400 Hz, the temperature rise first decreases and then increases. The thickness of the boride zone and the carbon-enriched zone first decreases and then increases. When the ACF current is 3 A, the single phase Fe2B is obtained. When the ACF current is not more than 2 A, with the increase of the ACF frequency, the boride zone changes from the dual phases FeB ＋ Fe2B to the single phase Fe2B. The hardness of the surface layer decreases. The slope of the hardness profile along the boriding case becomes fiat. It is proposed that the ACF frequency affects the pack boriding through affecting reactions among the boriding agent, adsorptions of active boron atoms and boron- containing species on the samples＇ surface, and diffusion in the treated samples.
出处
《中国表面工程》
EI
CAS
CSCD
北大核心
2018年第1期39-44,共6页
China Surface Engineering
基金
国家自然科学基金(51171032)~~
关键词
频率
交流电场
粉末法渗硼
渗硼层
组织
frequency
alternating current field
pack boriding
boriding case
microstructure
