Q355钢焊接性及其与Q345钢焊接技术的关键比较

根据国家标准GB/T1591-2018《低合金高强钢》和建筑钢结构工程实例,从钢材的化学成分入手分析Q355和Q345的本质区别,基于碳当量概念进一步阐述Q355低碳、微合金、纯净化、细晶粒特点,进一步论证了Q355是典型的细晶粒新钢种这一客观事实.分析认为:高强钢种焊接接头的强度、细化晶粒等指标与钢材的微合金元素直接...

Weldability of Q355 Steel and Key Comparison of Welding Technology between It and Q345 Steel

According to the national standard GB/T1591-2018 "Low-alloy High-strength Steel" and the examples of steel structure construction, this paper analyzes the essential difference between Q355 and Q345 based upon the chemical composition of the steel. It further expounds upon the characteristics of Q355 low carbon, micro-alloy, pure purification and fine grain with the concept of carbon equivalent, which illustrates the objective fact that Q355 is a typically new type of fine grain steel. Based on the analysis, this paper only considers that the strength and grain refinement of the welded joints of high-strength steel are directly related to the micro-alloyed elements of steel. The welding thermal cycle will cause the loss of alloying elements. Therefore, the loss of alloying elements will increase after one more thermal cycle, which is unfavorable to the quality of welded joint and will inevitably reduce the comprehensive properties of the welded joint. This is the key to welding Q355 steel.