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    堆焊电流对Fe-Cr-W-Nb高温耐磨药芯焊丝熔覆层组织及性能的影响

    Effect of Surfacing Current on Microstructure and Properties of Fe-Cr-W-Nb High-Temperature Wear-Resistant Flux Cored Wire Cladding Layer

    • 摘要: 设计了一种Fe-Cr-W-Nb高温耐磨药芯焊丝,采用埋弧堆焊技术在不同堆焊电流(350,400,450,500 A)下在Q235钢基体表面制备熔覆层,研究了堆焊电流对熔覆层组织、显微硬度及高温耐磨性的影响。结果表明:不同堆焊电流制备的熔覆层均主要由Fe-Cr固溶体、M23C6、NbC以及少量M7C3、Fe3W3C等物相组成;随着堆焊电流的增大,NbC硬质相颗粒生长逐渐充分,当堆焊电流为450A时,熔覆层硬质相颗粒生长最为充分,尺寸一致,分布均匀,熔覆层与钢基体形成良好的冶金结合;当堆焊电流过大(500 A)时,硬质相颗粒互相连接形成不规则形状,尺寸明显粗大,分布不均匀。随着堆焊电流的增大,熔覆层的平均显微硬度先增大后减小,磨损质量损失先减小后增大,当堆焊电流为450 A时,平均显微硬度最大,磨损失量最小,耐磨性能最优,磨损机制为氧化磨损。

       

      Abstract: A kind of Fe-Cr-W-Nb high-temperature wear-resistant flux-cored wire was designed, and the cladding layer was prepared on the surface of Q235 steel matrix by submerged arc surfacing technology under different surfacing currents (350, 400, 450, 500 A)., The effects of surfacing current on the microstructure, microhardness and high temperature wear resistance of the cladding layer were studied. The results show that the cladding layers prepared by different surfacing currents were mainly composed of Fe-Cr solid solution, M23C6, NbC and a small amount of M7C3 and Fe3W3C. With the increase of surfacing current, the growth of NbC hard phase particles was gradually sufficient. When the surfacing current was 450 A, the hard phase particles of the cladding layer grew most fully, and the size was consistent, the distribution was uniform, and the cladding layer formed a good metallurgical bond with the steel matrix. When the surfacing current was too large (500 A), the hard phase particles were connected to each other to form an irregular shape, and the size was obviously coarse and and the distribution was uneven. With the increase of the surfacing current, the average microhardness of the cladding layer first increased and then decreaseds, and the wear quality loss first decreased and then increased. When the surfacing current was 450 A, the average microhardness was the largest, the wear loss was the smallest, and the wear resistance was the best, and the wear mechanism was oxidative wear.

       

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