激光重熔对电冶钢结硬质合金DGJW40组织影响的研究

Influence of laser surface re-melting on microstructure of steel-bonded carbide DGJW40 alloy prepared by electro-slag melting and casting

用5.0kW横流CO2激光器对电冶钢结硬质合金DGJW40表面进行重熔处理,对重熔区显微组织结构进行了研究。结果表明:激光重熔区分为熔凝区、过渡区及热影响区,熔凝区组织细小且致密,由钢基体相和碳化物构成;大颗粒WC部分溶解、被碎化,小颗粒碳化物完全溶解;相比于钢基体,过渡区碳化物数量增多,该区的厚度与激光扫描速度成相反的变化;热影响区为相变硬化区,小颗粒碳化物也有所增多。经过激光重熔处理的DGJW40合金表层由WC、Fe3C、Cr7C3、Fe2W2C、Fe3W3C、-αFe、-γFe等组成。

Steel-bonded carbide DGJW40 alloy obtained by electro-slag melting and casting was melted using a transverse flow CO2 laser with the maximum power of 5.0kW and the microstructure of melted layer was studied. The results show that there are three zones： melted zone, transition zone and heat affected zone in the laser melted layer. The melted zone consists of carbides and matrix phases with refined microstructure. Big WCp is partially dissolved in the melted zone while fine carbides are dissolved completely. The amount of carbides is increased in transition zone and heat affected zone compared to the substrate. The depth of transition zone decreases with increasing the laser scan speed. Phase transformation occurs in the heat affected zone. The hardness of the melted zone is improved because of refining microstructure. Phases in melted zone of DGJW40 alloy by laser treating consist of WC,Fe3C,CrTC3, FeaWEC,Fe3W3C, α-Fe and γ-Fe.