硬质合金YG8与D6A异种金属CO_2激光焊接接头组织和性能的研究

利用CO_2激光器对双金属带锯条齿部用硬质合金YG8及背部用超高强度钢D6A进行焊接,通过金相显微镜,扫描电镜(SEM),显微硬度仪,电子显微探针(EPMA)等手段研究了焊后硬质合金YG8与超高强度钢D6A焊接接头组织演变规律,焊接接头合金元素分布,以及不同焊接工艺对异种金属焊接接头组织及力学性能的影响.研究表明,随着焊接速度增大,焊缝中心区等轴晶增多,树枝晶减少,且靠近YG8侧熔合区的等轴晶更细小;各种工艺条件下焊接接头硬度均较母材高,且靠近YG8侧的熔合区的硬度要高于焊缝区的硬度.当焊接功率为3 960 W,焊接速度为9m/min时,焊接接头的性能优良,抗弯强度值达到349 MPa,达到双金属带锯条的焊接性能要求.

Study of the Microstructure and Properties of YG8/D6A Dissimilar Metal CO2 Laser Welding Joints

Cemented carbide wires YG8 and ultrahigh-strength steel strips D6A were welded on the band saw blade by using CO2 laser.The typical microstructure of welding joints,the distribution of element,and influence of different bonding technologies on welding joints microstructure and mechanical properties were studied by using metalloscope,electron microscope(SEM),microhardness meter and electron(EPMA).The results showed that isometric increased,dendrite decreased in the weld center and isometric near the side of YG8 fusion boundary area became more fine with the increase of welding speed .The hardness of the welding joints every bonding technology was higher than parent metal.Moreover,the hardness of the bond area near the side of YG8 was higher than the welded zones.When the welding power was 3 960 W and the welding speed was 9 m/min,the property of the wedded joints was good,and the value of bending strength reached 349 MPa,which reached the requirements of double metal band saw blade welding.