超低碳贝氏体钢HAZ组织、性能及硼分布

Microstructure, Property and Boron Distribution of HAZ in An Ultra-low Carbon Bainitic Steel Bearing Cu-Nb-B

用Gleeble－1500热模拟机对Cu－Nb－B系超低碳贝氏体钢进行不同焊接工艺下热模拟试验，选定峰值温度为1340℃，高温停留0．5s，t(8/5)，分别取30，45，60s．研究了焊接热影响区（HAZ）组织、性能和硼的分布．结果表明：此类钢在不同焊接条件下，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．进一步探讨了不同t(8/5)；对钢中贝氏体组织组成及形态的影响，以及组织和低温韧性的关系．用径这显微照相技术（PTA）显示了硼在热影响区的行为．

Microstructure, properties and boron distribution of HAZ in an ultra-low carbon bainitic steelbearing Cu-Nb-B were investigated. Results indicated that excellellt low temperance toughness could be obtained the HAZ. The influence of cooling time (t_(8/5)) from 800 to 500℃ on bainitic morphology and the effectof microstructure on low temperature toughness were discussed. When cooled at medium rate, a part of granular bainite forms at higher temperature and then the most pan of austenite transforms into a finer lath bainiteforms at lower temperature, this microstructure has better low temperature toughness.