Structure-Processing Relationships for Welding New Steels with Small Alloying Additions

焊接添加少量合金的新钢的组织-加工关系

• 批准号: 544277-2019
• 负责人: Mendez, Patricio
• 金额: $ 9.53万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=693434
• 关键词: Structure; Processing; Relationships; Welding; New

The proposed research will address practical problems of weldability which are encountered by the industry on a daily basis when determining the feasibility of welding certain alloys, the need for heat treatment, or the potential for cracking. The welding of steel is currently based mostly on an accumulation of empirical knowledge, and quantitative use of fundamental knowledge of phase transformations and processing phenomena is rare. While the current empirical base of knowledge has been helpful with traditional steels, it is unable to provide reliable guidelines for modern steels which have small amounts of alloying elements that affect the microstructure. Among the steels not well understood for welding are fire-resistant steels, seismic steels, high grade microalloyed pipeline steels, and traditional structural steels with microalloying elements accepted in the new revised standards. Current troubleshooting efforts in industry aim at expanding the empirical knowledge base by trial and error, which is a slow, expensive, and wasteful approach when it needs to be repeated across multiple applications. The scientific objective of the proposed work is to predict the properties of a weld such as hardness, strength, residual stresses, or cold cracking susceptibility by using weld parameters accessible in practice such as current, voltage power, travel speed, heat input, and deposition rate. The project approach is simultaneously theoretical and experimental. The theoretical part involves metallurgy and heat and mass transport, and theories of phase transformations, moving heat sources, and mass and energy balances. The experimental part involves metallography and dilatometry, testing of mechanical properties, thermal imaging of welding, and testing of full-scale prototypes. The new knowledge generated will be transferred to Canadian industry as a set of reliable, quantitative guidelines for best practices in the design of weldments for steels with current compositions. Canadian industry will benefit from expanded abilities to deal with new steels, faster development of welding procedures, and a capability to weld with higher quality and higher productivity.

拟议的研究将解决行业在确定焊接某些合金的可行性、热处理的需要或裂纹的可能性时每天遇到的可焊性的实际问题。目前钢材的焊接大多基于经验知识的积累，而对相变和加工现象的基础知识的定量运用还很少。虽然当前的经验知识基础对传统钢有帮助，但无法为含有少量影响微观结构的合金元素的现代钢提供可靠的指导。新修订标准中接受的焊接钢种包括耐火钢、抗震钢、高等级微合金管线钢以及含有微合金元素的传统结构钢。目前业界的故障排除工作旨在通过反复试验来扩展经验知识库，当需要在多个应用程序中重复时，这是一种缓慢、昂贵且浪费的方法。拟议工作的科学目标是通过使用实践中可用的焊接参数（例如电流、电压功率、行进速度、热输入和熔敷）来预测焊缝的特性，例如硬度、强度、残余应力或冷裂纹敏感性速度。该项目方法同时具有理论性和实验性。理论部分涉及冶金学、热量和质量传递、相变理论、移动热源以及质量和能量平衡。实验部分涉及金相和膨胀测量、力学性能测试、焊接热成像以及全尺寸样机测试。产生的新知识将作为一套可靠的定量指南转移到加拿大工业界，用于设计当前成分的钢焊件的最佳实践。加拿大工业将受益于新钢材处理能力的扩大、焊接工艺的更快开发以及更高质量和更高生产率的焊接能力。