【摘要】：大線能量焊接的出現(xiàn)極大的提高了船舶制造效率,但大線能量焊接條件下,焊接熱影響區(qū)組織嚴(yán)重粗化導(dǎo)致鋼的力學(xué)性能斷崖下降,為解決焊接熱影響區(qū)組織粗化這一問題,本論文針對(duì)工業(yè)生產(chǎn)的含Mg船板鋼進(jìn)行了一系列的實(shí)驗(yàn)研究。首先針對(duì)焊接線能量對(duì)船板鋼HAZ沖擊韌性的影響開展了包括沖擊試驗(yàn)、斷口分析和金相組織分析等一系列的研究。實(shí)驗(yàn)結(jié)果表明:在-20℃下,16mm和40mm厚的鋼板在大線能量焊接后HAZ沖擊功均超過160J,而25mm的沖擊功為57.5J,但三者均達(dá)到了國標(biāo)要求;16mm和40mm厚的鋼板熱影響區(qū)斷口為典型的韌性斷裂,25mm厚的鋼板為準(zhǔn)解理斷裂;在金相組織方面,三種鋼板熱影響區(qū)均誘發(fā)了大量的晶內(nèi)針狀鐵素體,使組織細(xì)化,甚至優(yōu)于母材組織;25mm厚鋼板熱影響區(qū)沖擊韌性相對(duì)較低的原因一方面是所承受熱負(fù)荷較大,另一方面則是其母板原始組織相對(duì)粗大。其次為探明連鑄坯中IGF的誘發(fā)機(jī)制,進(jìn)行了冷卻速率、鋼中夾雜物尺寸及分布等因素對(duì)鑄態(tài)組織中IGF誘發(fā)的影響研究。結(jié)果表明:對(duì)試驗(yàn)鋼種而言,夾雜物的尺寸和分布是該類鋼種鑄態(tài)組織的決定性因素,而冷卻速率對(duì)其影響不大;與鋼板焊接熱影響區(qū)中能夠誘發(fā)IGF的夾雜物尺寸多為3μm以下相比,在鑄坯中能夠誘發(fā)IGF的夾雜物多為5~15μm。最后對(duì)比研究了溫度對(duì)含Mg船板鋼鑄態(tài)和軋態(tài)組織的影響。結(jié)果表明:鑄態(tài)組織中針狀鐵素體的溫度轉(zhuǎn)變區(qū)間在730℃-760℃之間,730℃誘發(fā)情況最佳;本實(shí)驗(yàn)鋼由于采用鎂處理,無論鑄態(tài)還是軋態(tài)組織隨著溫度的升高奧氏體晶粒并未呈一直長大的趨勢。
[Abstract]:The appearance of large wire energy welding has greatly improved the ship manufacturing efficiency. However, under the condition of large wire energy welding, the microstructure coarsening of the weld heat affected zone leads to the deterioration of the mechanical properties of the steel, in order to solve the problem of the microstructure coarsening in the welding heat affected zone. In this paper, a series of experiments are carried out on industrial steel with Mg. Firstly, a series of research including impact test, fracture analysis and metallographic structure analysis were carried out on the effect of welding line energy on HAZ impact toughness of shipboard steel. The experimental results show that at -20 鈩，

本文編號(hào)：2204485