V、N共存埋弧焊焊缝中V的析出相行为的研究

已有的15MnVN钢工字梁大线能量理弧焊研究结果表明,焊缝的强度总是过高而韧性偏低。本文利用透射扫描电镜和能谱仪研究了Mn-V-N和Mn-Mo-V-N系焊缝中V的析出相行为和V、N的存在形式及其对焊缝强韧性的影响。试验表明,在焊态或SR态下,由于焊缝冷速大,或因重复加热温度不够高,V、N均不能以非共格形式析出。V的共格析出是使焊缝强度过高和韧性偏低的重要原因。

A STUDY OF THE V PRECIPITATION BEHAVIOR IN V AND N COEXISTENT SUBMERGED ARC WELDS

The investigations in the past show that the weld metals of 15MnVN steel by SAW process with high heat input usually have over high strength and comparatively low toughn(?)ss. In this paper, the precipitati(?)n (?)ehavior of V and the existing forms of V and N in the weld metals of Mn-V-N and Mn-Mo-V-N systems were investigated, with STEM and EDAX methods. Their effects on the strength and the toughn(?)s of the weld m(?)tals w(?)re studi(?)d. This w(?)rk proved that under as-welded or SR treatment conditions V and N in the weld metals do not precipitate incoherently since the cooling rat(?) of the weld is so high and the reheat temperature is so low. The coherent precipitation of V is the main factor which makes the st(?)ength of the weld metal very high but the toughness comparatively low.