H13钢低温固体渗硼及其热熔损性能的研究

Study on the Low-temperature Pack Boriding and Erosion Property of H13 Steel

采用低温固体粉末渗硼法对H13钢基体表面进行稀土催渗下的渗硼试验。通过扫描电镜(SEM)和X射线衍射(XRD)分析渗硼层的组织形貌和物相组成,并对未渗硼和低温渗硼试样的热熔损性能进行了对比研究。结果表明:H13钢经580℃粉末渗硼10h后,其表面形成了一层连续致密的硼化物层,厚度约10μm,硬度约19GPa。渗硼层主要由FeB和Fe2B两相组成。稀土元素的渗入,可以降低活性硼原子在基体中的扩散激活能,从而显著加快其在基体表层中的扩散速率。由于渗硼层隔绝了铝合金熔液和基体直接接触,渗硼试样的抗热熔损性能大幅提高。

Low-temperature pack boriding experiment under the condition of catalysis with rare earth(RE) elements was carried out on H13 steel with a method of solid powder boronizing. The morphology and phase composition of boronizing layer were analyzed by SEM and XRD, respectively. Meanwhile, the comparative study on erosion properties of the borided sample and the untreated one were carried out. The experimental results showed that a continuous borided layer was formed on the surface of H13 steel after pack boriding at 580 ℃ for 10 h. The thickness of borided layer was about 10 μm and the hardness was about 19 GPa. The borided layer was composed of Fe 2B and FeB phases. Furthermore, the diffusion activation energy of the active boron atoms into substrate could be reduced by the diffusion of rare earth into the surface layer of H13 steel, thus significantly accelerating the diffusion rate of active boron atoms. Because the boronizing layer was isolated from the direct contact between molten aluminum alloy from substrate, the erosion resistance of borided sample was improved remarkably.