Scholarlink

<p>The growing use of advanced high-strength steels (AHSS) in the automotive and structural sectors requires joining methods that ensure both high strength and reliability. Although laser spot welding (LSW) shows significant potential, comprehensive studies integrating statistical design of experiments (DOE) with microstructural and mechanical characterization remain limited. In particular, gaps exist in correlating welding parameters with weld nugget quality, the strength–ductility balance, and heat-affected zone (HAZ) evolution across different AHSS grades. This study addresses these gaps by investigating the microstructural evolution and mechanical performance of laser spot welds in AHSS grades 590 and 980 (1&#xa0;mm thickness), supported by statistical optimization using response surface methodology (RSM). Experiments were conducted with an IPG fiber laser system (maximum capacity: 6000 W, applied power: up to 2000 W). A total of 20 experimental conditions were evaluated, considering five levels of laser power (1200–2000 W) and four levels of welding duration (800–1400&#xa0;ms). The results indicate that higher laser power and longer welding time produced larger weld nuggets and stronger joints. The optimal conditions were identified at 1800 W and 1400&#xa0;ms, yielding a nugget diameter of 7.65&#xa0;mm and a shear force of 11.35 kN. Shear testing revealed mixed ductile and brittle fracture modes, while microstructural analysis showed grain refinement and hardness variations within the HAZ, with the highest hardness observed in the hardening zone. The developed RSM model accurately predicted shear force, with errors ranging from 0.14% to 8.35%. ANOVA confirmed the RSM model’s significance (F = 44.38, <i>p</i> &lt; 0.0001), demonstrating strong predictive accuracy (R<sup>2</sup> = 96.28%) and low error (S = 0.400095), validating its reliability for statistical optimization. These findings highlight the critical role of microstructural evolution and mechanical performance in achieving balanced weld quality, providing practical guidelines for the effective application of laser spot welding in the automotive and manufacturing industries.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Microstructural Evolution and Mechanical Performance of Laser Spot Welds in Advanced High-Strength Steels: Statistical Optimization via Response Surface Methodology

  • 期刊论文

  • 发表日期：

    2026年3月4日

查看全文
  • Apichat Sanrutsadakorn,
  • Weerapong Julsri

摘要

The growing use of advanced high-strength steels (AHSS) in the automotive and structural sectors requires joining methods that ensure both high strength and reliability. Although laser spot welding (LSW) shows significant potential, comprehensive studies integrating statistical design of experiments (DOE) with microstructural and mechanical characterization remain limited. In particular, gaps exist in correlating welding parameters with weld nugget quality, the strength–ductility balance, and heat-affected zone (HAZ) evolution across different AHSS grades. This study addresses these gaps by investigating the microstructural evolution and mechanical performance of laser spot welds in AHSS grades 590 and 980 (1 mm thickness), supported by statistical optimization using response surface methodology (RSM). Experiments were conducted with an IPG fiber laser system (maximum capacity: 6000 W, applied power: up to 2000 W). A total of 20 experimental conditions were evaluated, considering five levels of laser power (1200–2000 W) and four levels of welding duration (800–1400 ms). The results indicate that higher laser power and longer welding time produced larger weld nuggets and stronger joints. The optimal conditions were identified at 1800 W and 1400 ms, yielding a nugget diameter of 7.65 mm and a shear force of 11.35 kN. Shear testing revealed mixed ductile and brittle fracture modes, while microstructural analysis showed grain refinement and hardness variations within the HAZ, with the highest hardness observed in the hardening zone. The developed RSM model accurately predicted shear force, with errors ranging from 0.14% to 8.35%. ANOVA confirmed the RSM model’s significance (F = 44.38, p < 0.0001), demonstrating strong predictive accuracy (R2 = 96.28%) and low error (S = 0.400095), validating its reliability for statistical optimization. These findings highlight the critical role of microstructural evolution and mechanical performance in achieving balanced weld quality, providing practical guidelines for the effective application of laser spot welding in the automotive and manufacturing industries.