Optimization of the welding parameters of steels used in wind towers

最近炼钢技术的进步显著地改善了铁合金的机械性能，并产生了新的钢材类别，例如，高强度低合金（HSLA）钢，目前广泛用于造船、管道、核电站、压力容器、风力涡轮机塔等。位于萨斯卡通的日立加拿大工业有限公司广泛使用自动埋弧焊（SAW）工艺，用HSLA钢制造压力容器、涡轮机外壳、风力涡轮机塔和其他先进的工程部件。SAW工艺的特点是高热量输入，产生复杂的显微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。在焊接工业中，工程师面临的一个主要问题是选择适当的和最佳的输入过程控制变量组合，以达到期望的焊缝质量和所需的结构完整性。焊接参数选择不当，导致焊接缺陷，造成巨大的经济损失。因此，为了控制热影响区（HAZ）尺寸，获得所需的焊头尺寸和质量，并确保焊头的可预测性和可重复性，选择适当的工艺变量值是至关重要的，这对于获得高质量的焊接产品至关重要。制造业不断需要提高生产率，降低生产成本，提高焊接产品的可靠性。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。这个研究项目的成功不仅会导致现有的埋弧焊工艺知识的改进，而且还会增加日立加拿大工业公司和其他加拿大公司利用SAW工艺的盈利能力。这也将对加拿大焊接技术产品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.