文章信息/Info

Title:

Failure Analysis of Drain Tube for Hot-Blast Stove

文章編號(hào):

16743962(2019)11112104

作者:

蔡曉文; 陳興元

（攀鋼集團(tuán)研究院有限公司 釩鈦資源綜合利用國(guó)家重點(diǎn)實(shí)驗(yàn)室，四川 成都 610300）

Author(s):

CAI Xiaowen;  CHEN Xingyuan

（State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization, Pangang Group Research Institute Co., Ltd., Chengdu 610300, China）

關(guān)鍵詞:

沿晶裂紋; 膨脹接頭; 蠕變應(yīng)變; 脆性斷裂; 高溫氧化

Keywords:

intergranular crack;  expansion joint;  creep strain;  brittle fracture;  high temperature oxidation

分類號(hào):

TF578

DOI:

10.7502/j.issn.1674-3962.201808043

文獻(xiàn)標(biāo)志碼:

A

摘要:

某不銹鋼制成的熱風(fēng)爐出風(fēng)管膨脹接頭過(guò)早失效。主要現(xiàn)象表現(xiàn)為熱風(fēng)爐出風(fēng)管膨脹接頭于失效處壁厚減薄，并伴隨破裂、穿孔等現(xiàn)象。經(jīng)取樣觀察，膨脹接頭在減薄處存在裂紋，局部坍塌凹陷。通過(guò)掃描電子顯微鏡（SEM）對(duì)裂紋處斷口形貌進(jìn)行觀察，發(fā)現(xiàn)斷口處穿晶和沿晶裂紋并存。利用傳統(tǒng)金相檢驗(yàn)及化學(xué)分析等方法多角度分析了缺陷樣品的形貌及成分。結(jié)果顯示，工件的環(huán)境溫度和蠕變?cè)黾恿司Я４只�和形成楔形空穴的趨�?shì)。腐蝕、蠕變、晶界析出物析出之后基體的貧鉻引起了出風(fēng)管管壁變薄、開(kāi)裂并最終導(dǎo)致熱風(fēng)管過(guò)載失效。

Abstract:

Stainless steel drain tube from a hot-blast stove for the preheating air was premature failure. The main phenomenon was that the wall thickness of the expansion joint of the hot�瞐ir stove-s air outlet tube was reduced at the failure point，with cracking and punching. It was observed that certain areas occurred through-way cracking in the thinned tube while others showed significant collapsing. A fracture taken from cracking areas was analyzed by SEM and was found to have a mixture of intergranular and transgranular cracking. Metallographic examination and chemical analysis of two specimens, also from the failed region, revealed the presence of large grain with widened grain boundary and wedge-type cavities at grain-boundary triple points, which were caused by operating temperature exceed those intended for this steel and may be promoted by grain-boundary precipitates. Failure of the tube was attributed to creep-type rupture at high-temperature conditions resulting from prolonged overheating and to thinning of the way by high-temperature corrosion and oxidation to the point at which the hot-air pressure in the tube and eventually lead to overload failure of the hot air pipe.