超低碳贝氏体钢焊接热影响区冲击韧性的研究

用Ｇｌｅｅｂｌｅ－１５００热模拟机对含铜超低碳贝氏体钢进行不同焊接工艺下热模拟试验。研究了焊接热影响区的组织、性能。探讨了不同ｔｓ／５对钢中贝氏体组织组成及形态的影响以及组织与低温韧性的关系。用径迹显微照相技术（ＰＴＡ）显示了硼在热影响区的行为。结果表明：在不同焊接条件下，此类钢焊接热影响区均具有较好的低温韧性和较低的韧脆转变温度。当以中等速率冷却时，高温时生成的一定量的粒状贝氏体可有效地分割奥氏

Study on Impact Toughness of HAZ in Ultra-Low Carbon Bainitic Steel

Microstructure, properties and boron distribution of HAZ in an ultra low carbon bainitic Cu containing steel were investigated by welding simulation on a Gleeble 1500 thermal simulator. The influence of t 8/5 on bainitic morphology and the microstructure on low temperature toughness were discussed. PTA (particle tracking autoradiograph) technology was employed to display the distribution of B in HAZ. The results indicated that excellent low temperature toughness and lower FATT could be obtained under different welding conditions in HAZ. When cooled at medium rate, the granular bainite formed at higher temperature divide the austenite grain, and result in forming a finer lath bainite at lower temperature which has better low temperature toughness.