含Mg夹杂物对低合金高强度钢CGHAZ韧性的影响

摘要：采用Ca、Mg处理工艺研究不同夹杂物粒子对200kJ/cm大线能量焊接低合金高强度钢CGHAZ冲击韧性的影响，对各个试样CGHAZ的显微组织，晶粒尺寸和冲击功进行观察和分析。试验结果表明，在低合金高强度钢CGHAZ中，Mg处理钢的冲击性能明显高于Ca处理钢，主要原因是含Mg夹杂物粒子析出能力比含Ca夹杂物粒子强，在焊接过程中，含Mg夹杂物粒子对CGHAZ组织的钉扎作用更加显著；同时提高针状铁素体的含量，延长裂纹扩展路径，提高断裂时吸收的能量，使样品韧性得到提升。

Effect of inclusions on toughness for low alloy high strength steel CGHAZ

The influence of different inclusion particles on the impact toughness of low alloy high strength steel CGHAZ of 200kJ/cm high heat input welding low alloy high strength steel was studied by Ca and Mg treatment process. The microstructure, grain size and impact energy of each specimen CGHAZ were observed and analyzed. The test results show that in the low alloy high strength steel CGHAZ, the impact properties of Mg treated steel were significantly higher than that of Ca treated steel. The main reason is that the precipitation ability of Mg inclusion particles is stronger than that of Ca inclusion particles. In the welding course, Mg inclusion particles have more significant pinning effect on CGHAZ microstructure, not only increasing the content of acicular ferrite, extending the crack propagation path, but also increasing the energy absorbed during fracture, and improving the toughness of the specimen.