GH163合金TIG焊缝异常组织的控制

ＧＨ１６３合金薄板ＴＩＧ焊缝中出现的黑色线性组织是航空发动机加力燃烧室焊接成形时突出的质量问题之一。本文对这种异常组织的形成机制及其控制方法进行了研究。结果表明，黑色线性组织是由焊缝金属中轻金属元素的偏析引起的。随着焊接线能量减小，轻金属元素的偏析程度降低，黑色线性组织变窄。当焊接线能量减小至０．４５ｋＪ／ｃｍ左右时，即可消除黑线。

On Controlling Abnormal Black-line Structure in TTG Welds of GH163 Alloy

In China production of aircraft engine afterburner, an abnormal black- line, detected inthe center of weld after welding of GH163 alloy material, is an important quality problemwhich has not yet been solved satisfactorily. We present now a method which can almostcompletely eliminate it.with the help of x- ray deflection test, metallographic examination, and the scanningelectron microscope, we examine the causes underlying the black - line structure. We findthat it is not due to metallurgical defects such aS welding craeks. A black- line, which frequently appears due to dual cryStal plane diffraction, is not the black- line we are interestedin' We find that it results from the segregation of light metal elements such as aluminum andtitanium which occurs because of high heat input leading to high puddle crystallizing rate.Therefore, the black- line structure can be removed if the welding heat input is controlled tobe about 0. 45kJ/cm.