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在现代化工业建设中,焊接结构正日益大型化,低合金高强度钢在焊接结构中的应用越来越广,对钢强度的要求也必然逐渐提高。仅就我国桥梁用钢而言,目前已从屈服强度35kg/mm~2向45kg/mm~2和60kg/mm~2强度级别发展。因此,为适应高强度、大型化焊接结构的需要,对低合金高强度焊缝金属性能的研究及其焊接材料的研制就成为当前急待解决的重要课题。本文是根据σ_s≥60kg/mm~2低合金高强度钢性能的要求( ≥75kg/mm~2, ≥60kg/mm~2,时效冲击韧性大于3.5kg-M/Cm~2,-40℃冲击韧性大于3.0kg-M/Cm~2)进行了可焊性和焊接材料研制的试验。结合国内资源条件,选 Mn、Mo 为主要强化元素,在 Mn-Mo、Mn-Mo-Nb、Mn-Mo-W、Mn-Mo-V、Mn-Mo-V-N-Nb,Mn-Mo-W-Nb-Cu 以及 Mn-W-Cu 等合金系统中,以 Mo、W、Nb、V、Cu 等元素对焊缝金属机械性能和抗裂性能的影响,进行了系统的试验研究。试验结果,认为 Mn-Mo、Mn-Mo-V、Mn-Mo-W、Mn-Mo-Nb 等合金系统的焊缝金属性能较为满意,并确定了合金元素系统中各元素可取的含量范围,为研制适用于≥60kg/mm~2钢的焊接材料确定了理论基础。
In the modern industrial construction, welding structure is increasingly large-scale, low-alloy high-strength steel in the welding structure is more widely used, the strength of the requirements of the inevitable gradual increase. As far as our country’s bridge steel is concerned, it has been developed from the yield strength of 35kg / mm ~ 2 to the strength of 45kg / mm ~ 2 and 60kg / mm ~ 2. Therefore, in order to meet the needs of high-strength, large-scale welded structures, research on low-alloy high-strength weld metal properties and the development of welding materials has become an urgent issue to be solved. This article is based on the σ_s ≥ 60kg / mm ~ 2 low alloy high strength steel performance requirements (≥ 75kg / mm ~ 2, ≥ 60kg / mm ~ 2, aging impact toughness greater than 3.5kg-M / Cm ~ 2, -40 ℃ impact Toughness greater than 3.0kg-M / Cm ~ 2) were tested for weldability and welding material development. According to the domestic resource conditions, Mn and Mo are selected as the main strengthening elements, and Mn-Mo, Mn-Mo-Nb, Mn-Mo-W, Mn-Mo-V, Mn-Mo-VN-Nb and Mn-Mo-W -Nb-Cu and Mn-W-Cu alloy systems, the effects of Mo, W, Nb, V, Cu and other elements on the mechanical properties and crack resistance of the weld metal were systematically studied. The results show that the weld metal properties of Mn-Mo, Mn-Mo-V, Mn-Mo-W and Mn-Mo-Nb alloy systems are satisfactory and the content range of each element in the alloying element system is determined. The theoretical basis for the development of welding materials suitable for ≥60kg / mm ~ 2 steel has been established.