【摘要】：Mn18Cr18N護(hù)環(huán)鋼作為高氮鋼中一種具有優(yōu)異的抗高強(qiáng)度、抗應(yīng)力耐腐蝕性能的鋼種,其研究和冶煉受到國內(nèi)外的高度重視。因此對Mn18Cr18N護(hù)環(huán)鋼冶煉的理論基礎(chǔ)及其材料性能的深入研究對于推動(dòng)我國護(hù)環(huán)鋼的制備具有重要的意義。通過引用規(guī)則溶液的性質(zhì),建立了鋼液增氮的熱力學(xué)模型,分析了不同因素對增氮的影響,并將溶解度模型與實(shí)際結(jié)果進(jìn)行對比；分析了不同情況下增氮?jiǎng)恿W(xué)的限制環(huán)節(jié),為實(shí)際操作起到一定的指導(dǎo)作用；分析了鋼液凝固時(shí)氮偏析出的控制要素,為防止氮在鋼液凝固時(shí)的析出提供了理論依據(jù)。通過在常壓下進(jìn)行增氮的實(shí)驗(yàn)研究,分析了采用氮?dú)庠龅c氮化合金增氮的增氮效果,得出了采用氮?dú)夂偷辖鹨黄鹪龅Ч徒?jīng)濟(jì)性最佳、在采用氮化合金增氮的最佳冶煉溫度；分析了冶煉溫度對增氮的影響,得出采用氮?dú)庠龅獣r(shí)最佳冶煉溫度為1650℃,采用氮化合金增氮時(shí)最佳冶煉溫度為1550℃。通過采用真空感應(yīng)爐+氮?dú)獗Ｗo(hù)電渣重熔雙聯(lián)工藝制備出氮含量均在0.63%以上的Mn18Cr18N鋼；分析電渣重熔錠不同參數(shù)對電渣重熔制備Mn18Cr18N鋼質(zhì)量的影響。通過采用Procast軟件對Mn18Cr18N護(hù)環(huán)鋼進(jìn)行微觀組織模擬研究,分析了不同工藝參數(shù)對微觀組織形貌、晶粒數(shù)量、晶粒平均半徑、二次枝晶間距的影響,得出了最佳的凝固參數(shù),可使晶粒數(shù)量增加了30.58%,晶粒平均半徑減小了38.39%,二次枝晶間距減少了21.34%,為制備高質(zhì)量Mn18Cr18N鋼的實(shí)際生產(chǎn)提供了指導(dǎo)作用。通過對電渣重熔后的Mn18Cr18N電渣錠進(jìn)行熱加工性能研究,分析了Mn18Cr18N護(hù)環(huán)鋼的高溫拉伸力學(xué)性能、常溫拉伸斷裂形貌及斷裂機(jī)理分析以及高溫?zé)崴苄?可以得知在溫度為850℃～950℃區(qū)間及1100℃～1250℃區(qū)間的熱塑性好于950℃～1050℃區(qū)間。Mn18Cr18N熱加工區(qū)域應(yīng)控制在1100℃～1250℃區(qū)間以避免鐵素體組織的產(chǎn)生和產(chǎn)品開裂。
[Abstract]:As a kind of high nitrogen steel with excellent resistance to high strength and stress and corrosion resistance, the research and smelting of Mn18Cr18N ring steel have been attached great importance to at home and abroad. Therefore, it is of great significance to study the theoretical basis and material properties of Mn18Cr18N ring steel smelting in order to promote the preparation of protecting ring steel in China. By quoting the properties of regular solution, the thermodynamic model of nitrogen increasing in liquid steel was established, the influence of different factors on nitrogen increasing was analyzed, and the solubility model was compared with the actual results. The limiting links of nitrogen increasing dynamics under different conditions are analyzed, which will play a guiding role in practical operation, and the controlling factors of nitrogen segregation during liquid steel solidification are analyzed, which provides a theoretical basis for preventing nitrogen from precipitating during liquid steel solidification. Through the experimental study of nitrogen increasing under normal pressure, the effect of nitrogen increasing by nitrogen gas and nitriding alloy is analyzed. The results show that nitrogen gas and nitride alloy together increase nitrogen effect and economy best. The optimum melting temperature of nitrided alloy for increasing nitrogen; The effect of smelting temperature on nitrogen increase is analyzed. The optimum smelting temperature is 1650 鈩，

本文編號：2353774