Optimization of the welding parameters of steels used in wind towers

最近炼钢技术的进步显著提高了黑色金属合金的机械性能，并催生了新的钢种，例如高强度低合金(HSLA)钢，这些钢目前广泛应用于造船、管道、核电站、压力容器、风力涡轮机塔架等。SAW工艺的特点是热输入高，从而产生一个复杂的组织和成分不均匀区域，称为热影响区(HAZ)，其大小受几个焊接参数的影响。工程师在焊接行业面临的一个主要问题是选择适当和最佳的输入过程控制变量组合，以实现所需的焊道质量和所需的结构完整性。焊接参数选择不当会造成焊接缺陷，造成很大的经济损失。因此，选择合适的工艺变量对于控制热影响区(HAZ)尺寸、获得所需的焊道尺寸和质量以及确保可预测和可重复的焊道至关重要，而这对于获得高质量的焊接产品至关重要。制造业继续需要提高生产率、降低生产成本和改善焊接产品的可靠性。本研究的长期目标是通过优化焊接参数来提高埋弧焊的效率、生产率和成本效益。该研究项目的成功不仅将提高现有的埋弧焊工艺知识，还将增加日立加拿大工业公司和其他使用SAW工艺的加拿大公司的盈利能力。这也将对加拿大在焊接技术产品方面的全球竞争力产生积极影响。

Recent advances in steelmaking technology have remarkably improved the mechanical properties of ferrous alloys and given rise to new classes of steels, for example, high-strength low-alloy (HSLA) steels that are widely used today in shipbuilding, pipelines, nuclear plants, pressure vessels, wind turbine towers, etc. Hitachi Canadian Industries Ltd, Saskatoon, makes extensive use of the automated submerged arc welding (SAW) process for fabrication of pressure vessels, turbine casings, wind turbine towers and other advanced engineering components from HSLA steels. The SAW process is characterized by high heat inputs that give rise to a complex region of microstructural and compositional inhomogeneity called the heat-affected zone (HAZ), the size of which is affected by several welding parameters. One major problem engineers face in the welding industry is selecting appropriate and optimum combinations of input process-control variables in order to achieve the desired weld bead quality and the required structural integrity. Improper selection of welding parameters results in welding defects which cause high economic losses. Selecting appropriate values of process variables is therefore essential in order to control heat-affected zone (HAZ) dimensions, obtain the required bead size and quality, and ensure a predictable and reproducible weld bead, which is critical for obtaining high quality welded products. There is continued need in the manufacturing industry to increase productivity, reduce production cost and improve reliability of welded products. The long-term objective of this study is to increase submerged arc welding efficiency, productivity and cost effectiveness by optimizing the welding parameters. The success of this research project will not only lead to the improvement of the existing knowledge of submerged arc welding process but also increase the profitability of Hitachi Canadian Industries and other Canadian companies utilizing the SAW process. It will also have positive impact on the global competitiveness of Canada in welding technology products.