Correlation of Microstructures and Process Variables in FSW HSLA-65 Steel
Correlation of Microstructures and Process Variables in FSW HSLA-65 Steel
复制标题
FSW HSLA-65 钢显微组织与工艺变量的相关性
作者：
L. Y. Wei;T. Nelson
研究了搅拌摩擦焊接HSLA-65钢过程变量与焊后组织的关系。采用PCBN凸旋肩-阶梯螺旋（CS4）工具在各种参数范围内对HSLA-65钢进行了完全固结焊接。熔核中心的显微组织主要由板条贝氏体和部分多角形/同形晶界铁素体控制，与热输入高度相关。搅拌摩擦焊因变量与搅拌摩擦焊自变量之间呈非线性关系。热输入被确定为最佳参数指标。随着热输入的增加，贝氏体体积减小，铁素体晶粒尺寸和板条尺寸增大。热输入与半定量焊后组织之间建立了线性关系。
The present study focuses on developing a relationship between process variables and postweld microstructure in friction stir welded HSLA-65 steel. Fully consolidated welds were produced in HSLA-65 steel using a PCBN convex-scrolled-shoulder-step-spiral (CS4) tool over a wide range of parameters. Microstructures in the nugget center (NC) are governed by lath bainite and with some polygonal/allotriomorphic grain boundary ferrite, which are highly dependent on heat input. Friction stir welded dependent variables are related with FSW independent variables by nonlinear relationship. Heat input is identified as the best parameter index. With increasing heat input, the volume of bainite decreases and the ferrite grain and lath sizes increase. A linear relationship was established between heat input and semiquantitative postweld microstructures.