【摘要】：我國是貧鎳的國家,鎳需要大量進口,導(dǎo)致奧氏體不銹鋼的生產(chǎn)成本處于高位,為了解決這一問題,科研人員研發(fā)出了高氮不銹鋼。但是關(guān)于高氮奧氏體不銹鋼熱加工方面的報道相對較少,尤其是與不含氮奧氏體不銹鋼熱加工規(guī)律的差異研究較少,因此需要在這方面進行系統(tǒng)研究。對鑄態(tài)和鍛態(tài)N0.7試驗鋼進行熱處理,隨著加熱溫度和保溫時間的增加,兩種狀態(tài)的組織晶粒均呈長大趨勢;為使鑄態(tài)N0.7試驗鋼中的析出物充分溶解,同時組織中不易出現(xiàn)異常的長大晶粒,加熱溫度應(yīng)低于1200℃,保溫時間不超過4h。適合于鍛態(tài)N0.7試驗鋼的加熱制度為:加熱溫度1200℃,保溫1h;鑄態(tài)N0.7試驗鋼在800℃左右進行熱處理時,原始晶粒的晶界處出現(xiàn)片層狀析出物,其成分為Cr2N和轉(zhuǎn)變后的奧氏體。研究不同變形參數(shù)(變形溫度、應(yīng)變速率)對N0、N0.45及N0.7試驗鋼熱變形的影響;構(gòu)造出相應(yīng)的本構(gòu)方程,計算出變形表觀激活能QN0.45=823.31KJ/mol,QN0.7=524.84KJ/mol,QN0=479.59KJ/mol,為制定出合理的熱加工工藝提供理論依據(jù)。對高溫壓縮變形后的試樣進行組織觀察,隨著溫度的升高、應(yīng)變速率的降低,動態(tài)再結(jié)晶晶粒越多,動態(tài)再結(jié)晶進行越完全;氮含量的增加促進動態(tài)再結(jié)晶的進行。對N0.7試驗鋼進行高溫拉伸實驗。相同應(yīng)變速率下,溫度升高,變形抗力降低,塑性提高;1200℃時,應(yīng)變速率增加,變形抗力增加,同時由于溫度效應(yīng),熱塑性提高。
[Abstract]:In order to solve this problem, high nitrogen stainless steel has been developed in order to solve this problem because of the high production cost of austenitic stainless steel due to the large import of nickel in China. However, there are few reports on hot working of high nitrogen austenitic stainless steel, especially the difference between austenitic stainless steel and nitrogen free austenitic stainless steel. With the increase of heating temperature and holding time, the microstructure grains of as-cast and forged N0.7 test steels show a long trend, in order to make the precipitates in the as-cast N0.7 test steels dissolve fully. At the same time, it is not easy to appear abnormal grains in the microstructure, the heating temperature should be lower than 1200 鈩，

本文編號：2216481