本文選題：熱沖壓　切入點：模具設(shè)計　出處：《江蘇大學》2017年碩士論文　論文類型：學位論文

【摘要】：超高強鋼板熱沖壓成形技術(shù)是目前車企行業(yè)在不犧牲安全性能前提下減輕車身重量、實現(xiàn)節(jié)能減排的新型技術(shù)和重要途徑之一,其中的熱沖壓模內(nèi)淬火工藝是一個受多因素影響并決定組織轉(zhuǎn)變和制件質(zhì)量的核心過程,而淬火工裝則是保證工藝路線順利實施的基礎(chǔ)。因此,本文以超高強鋼B1500HS作為研究對象,立足于理論和實驗,重點對熱沖壓淬火階段核心工裝(熱沖壓模具)設(shè)計、淬火關(guān)鍵工藝參數(shù)(保壓壓強、保壓時間和冷卻水流速)以及用于淬火冷卻的溫度自動控制系統(tǒng)開發(fā)方面展開了系統(tǒng)的研究。(1)基于傳熱學理論,推導出了熱沖壓模具冷卻管道直徑d和冷卻管道中心距模面高度H的理論求解式并應用;同時結(jié)合連續(xù)淬火熱-力耦合模型對設(shè)計的模具水道的冷卻能力展開了預測分析。研究結(jié)果表明:根據(jù)預設(shè)淬火背景,應用理論求解式得出d為10mm、H為20mm時即可滿足使用要求。(2)自主搭建了一套壓力可調(diào)、溫度實時檢測的手動淬火實驗裝置,對熱沖壓保壓壓強、保壓時間和冷卻水流速三個淬火關(guān)鍵工藝參數(shù)展開了系統(tǒng)的實驗研究,并以淬火后試樣力學性能和微觀組織作為評價依據(jù),獲得了各工藝參數(shù)對淬火工藝的影響規(guī)律以及最優(yōu)工藝參數(shù)范圍。研究結(jié)果表明:針對厚度為1.2mm的B1500HS,為達到熱沖壓件標準,淬火中保壓壓強應不小于0.5MPa;為提高生產(chǎn)效率,最優(yōu)保壓壓強范圍應取15MPa以上;初始成形溫度為850℃,最佳保壓時間為10s;為滿足組織轉(zhuǎn)變速率要求,維持連續(xù)生產(chǎn)中溫度場動態(tài)平衡,冷卻水流速至少為5L/min。(3)為滿足熱沖壓淬火階段板料溫降速率要求,并針對板料各區(qū)域冷卻均勻性以及提高冷卻系統(tǒng)的自動化和通用性等問題,自主開發(fā)了熱沖壓淬火溫度自動控制系統(tǒng)。研究結(jié)果表明:該系統(tǒng)能使淬火后制件各區(qū)域皆為完全板條狀馬氏體,且淬火均勻性較好,硬度值達500HV,能夠滿足熱沖壓制件使用要求。
[Abstract]:Hot stamping technology for ultra-high strength steel plate is one of the new technologies and important ways to reduce body weight and achieve energy saving and emission reduction in the automotive industry without sacrificing safety performance. The quenching process in the hot stamping die is a core process which is affected by many factors and determines the structure transformation and the quality of the parts, and the quenching equipment is the basis to ensure the smooth implementation of the process route. Based on the theory and experiment, this paper focuses on the design of the core tooling (hot stamping die) during hot stamping and quenching, and the key technological parameters of quenching (pressure keeping), based on the research object of ultra-high strength steel (B1500HS). Based on the theory of heat transfer, a systematic study has been carried out on the development of automatic temperature control system for quenching and cooling. The theoretical formula of diameter d of cooling pipe and height of cooling pipe center from die surface H of hot stamping die is deduced and applied. At the same time, combined with the coupled model of continuous quenching heat and force, the cooling capacity of the designed die waterway is predicted and analyzed. The results show that: according to the preset quenching background, By applying the theoretical solution formula, it can be concluded that when d = 10mm H is 20mm, the manual quenching experiment device with adjustable pressure and real time temperature detection can be set up, which can maintain the pressure of hot stamping. Three key process parameters of quenching, pressure holding time and cooling water flow rate, were studied systematically, and the mechanical properties and microstructure of quenched samples were used as the basis for evaluation. The effects of various process parameters on quenching process and the optimum range of process parameters are obtained. The results show that for B1500HSwith thickness of 1.2mm, in order to meet the standard of hot stamping parts, the holding pressure in quenching should be not less than 0.5MPa, and in order to improve the production efficiency, The optimal pressure keeping pressure range should be above 15MPa, the initial forming temperature is 850 鈩，

本文編號：1650368