本文關(guān)鍵詞： 塑料模具鋼 NAK80鋼 NAK80-M鋼 固溶處理 時(shí)效處理　出處：《昆明理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著塑料制品的應(yīng)用越來越廣泛,塑料制品的種類愈加多樣化,表面質(zhì)量要求不斷提高,從而對(duì)塑料模具鋼的拋光性能要求越來越高,同時(shí)還對(duì)塑料模具鋼的耐腐蝕性提出了新的要求。目前市場上廣泛使用的高鏡面拋光性能塑料模具鋼是日本開發(fā)的NAK80時(shí)效硬化型預(yù)硬化塑料模具鋼。但國內(nèi)自主生產(chǎn)的NAK80鋼存在較大差距,對(duì)該鋼的生產(chǎn)關(guān)鍵技術(shù)未掌握,存在心部力學(xué)性能差、組織分布不均勻、淬透性不佳等問題,同時(shí),該鋼耐蝕性能較差,不能滿足塑料制品發(fā)展對(duì)模具鋼的耐蝕性要求。調(diào)制開發(fā)具備更優(yōu)異力學(xué)性能和耐蝕性能的新型時(shí)效硬化型塑料模具鋼具有重要意義。本文在NAK80鋼的基礎(chǔ)上,通過調(diào)整合金成分與優(yōu)化熱處理制度,研發(fā)出新型時(shí)效硬化型塑料模具鋼NAK80-M。與NAK80鋼相比,NAK80-M鋼中添加了 2.00%的Cr和0.15%的V,Mo的含量提高至0.76%,Ni和Cu的含量分別降低至1.50%和0.49%。通過研究合金元素變化對(duì)相組成和相變行為、微觀組織和力學(xué)性能、以及熱處理工藝的影響,得到以下主要結(jié)論:(1)熱力學(xué)計(jì)算與等溫轉(zhuǎn)變?cè)囼?yàn)結(jié)果表明,NAK80-M和NAK80兩種鋼的平衡相種類相同,但NAK80-M試驗(yàn)鋼的臨界溫度點(diǎn)Ac3、Ac1相對(duì)較高,使得碳化物的溶解溫度提高。(2)固溶處理后,NAK80和NAK80-M試驗(yàn)鋼獲得的組織主要由板條馬氏體和殘余殘余奧氏體構(gòu)成。分別在850℃和880℃下進(jìn)行2h的固溶處理,NAK80和NAK80-M鋼可獲得最高的硬度。同時(shí),對(duì)兩種鋼的峰值硬度進(jìn)行比較,可知NAK80-M鋼的硬度更高。(3)固溶+時(shí)效處理后,NAK80和NAK80-M試驗(yàn)鋼獲得的組織主要由板條馬氏體、粒狀貝氏體、殘余奧氏體和析出碳化物構(gòu)成。不同時(shí)效溫度的研究表明,NAK80-M鋼在880℃固溶2h后空冷,隨后進(jìn)行540℃時(shí)效,達(dá)到材料力學(xué)性能峰值,NAK80鋼在850℃達(dá)到材料力學(xué)性能峰值。不同時(shí)效時(shí)間研究表明,NAK80-M鋼在880℃固溶2h后空冷,隨后進(jìn)行540℃時(shí)效保溫4h后空冷,達(dá)到材料力學(xué)性能峰值。同時(shí)對(duì)比兩種鋼力學(xué)性能峰值數(shù)據(jù)可知,NAK80-M鋼的硬度和沖擊韌性值比NAK80鋼高出2.5HRC和50J。NAK80-M鋼的最佳熱處理工藝是:880℃固溶2h后空冷,隨后進(jìn)行540℃時(shí)效保溫4h后空冷。
[Abstract]:With the more and more extensive application of plastic products, the variety of plastic products is becoming more and more diversified, and the surface quality requirements are constantly improved, so the polishing performance of plastic die steel is required more and more. At the same time, new requirements for corrosion resistance of plastic die steel are put forward. The high mirror polishing performance plastic die steel widely used in the market at present is a NAK80 aging hardening prehardening plastic die steel developed by Japan. There is a big gap in domestic NAK80 steel. The key technology of production of the steel is not mastered, there are some problems such as poor mechanical properties of the center, uneven distribution of microstructure and poor hardenability. At the same time, the corrosion resistance of the steel is poor. It is of great significance to develop a new aging hardening plastic die steel with better mechanical properties and corrosion resistance. This paper is based on NAK80 steel. On the basis. By adjusting the alloy composition and optimizing the heat treatment system, a new aging hardening plastic die steel NAK80-M.Compared with NAK80 steel was developed. The content of 2.00% Cr and 0.15% V Mo in NAK80-M steel was increased to 0.76%. The contents of Ni and Cu were reduced to 1.50% and 0.49.The effects of the change of alloy elements on the phase composition, phase transformation behavior, microstructure and mechanical properties, as well as the heat treatment process were studied. The results of thermodynamic calculation and isothermal transformation test show that the equilibrium phases of NAK80-M and NAK80 steels are the same. However, the critical temperature point of NAK80-M test steel is relatively high, which makes the dissolution temperature of carbides increase. 2) after solution treatment. The microstructure obtained from NAK80 and NAK80-M test steels was mainly composed of lath martensite and residual austenite, and the solution was treated at 850 鈩，

本文編號(hào)：1451913