本文選題：熱沖壓 + B1500HS硼鋼�。� 參考：《山東科技大學(xué)》2017年碩士論文

【摘要】：人民物質(zhì)生活水平的上升以及日益嚴(yán)重的能源危機(jī)和環(huán)境問題,對汽車行業(yè)提出了新的更高要求。因此,安全、環(huán)保、節(jié)能、舒適現(xiàn)已成為汽車行業(yè)的熱點(diǎn)研究課題和方向。汽車車身輕量化是實(shí)現(xiàn)汽車節(jié)能減排的最有效措施之一。研究汽車的輕量化設(shè)計(jì)現(xiàn)已成為現(xiàn)代汽車設(shè)計(jì)制造的一項(xiàng)重要課題。熱沖壓成形工藝由于結(jié)合了沖壓變形和淬火的優(yōu)勢,即材料高溫時(shí)的良好成形性及冷卻時(shí)材料的相變強(qiáng)化,能夠生產(chǎn)出形貌完整、尺寸精確、強(qiáng)度高的熱沖壓件,而受到廣泛關(guān)注。熱沖壓工藝參數(shù)對板料的成形性能起著至關(guān)重要的影響。本文以B1500HS為研究材料,以U型沖壓件為研究對象進(jìn)行了相關(guān)研究,具體研究內(nèi)容為:1.利用自制模溫控制設(shè)備,研究了加熱和模具溫度對U型沖壓件不同部位組織性能的影響,結(jié)果表明:對于U型件不同部位,力學(xué)性能及一致性表現(xiàn)為:底部法蘭部位直壁部位;870℃保溫5min后冷卻,試樣發(fā)生不完全淬火,熱沖壓件的性能不滿足設(shè)計(jì)要求;加熱溫度達(dá)到900℃并逐漸升高,熱沖壓件的力學(xué)性能下降;隨著模具溫度的升高,熱沖壓件的力學(xué)性能呈梯度下降。當(dāng)模具溫度超過300℃及以上時(shí),試樣的微觀組織開始出現(xiàn)大量的貝氏體組織。2.通過控制沖壓設(shè)備的沖壓壓力,研究了壓力及保壓時(shí)間對于板料組織性能的影響,結(jié)果表明:在熱力耦合作用下,隨著壓力逐漸增加至40MPa,板料力學(xué)性能近似呈線性關(guān)系增加。壓力繼續(xù)增加,板料力學(xué)性能變化趨于穩(wěn)定。保壓時(shí)間較短時(shí)試樣的微觀組織顆粒粗大,力學(xué)性能較差。試樣的強(qiáng)、硬度隨著保壓時(shí)間的延長而增強(qiáng),在保壓時(shí)間為7.5s,試樣的組織形態(tài)變?yōu)榫鶆虻鸟R氏體,此時(shí)試樣的強(qiáng)、硬度較高,力學(xué)性能良好。3.通過DIL805A高溫相變儀,繪制了 B1500HS的熱膨脹曲線。并結(jié)合金相觀察和硬度測試,分析了加熱和冷卻速度對于板料組織性能的影響。結(jié)果表明:800℃并未達(dá)到試樣的奧氏體化開始溫度,由于珠光體轉(zhuǎn)變需要孕育期,冷速越快,珠光體在奧氏體晶界處的先共析相(此時(shí)為鐵素體)上形核越困難,導(dǎo)致珠光體轉(zhuǎn)變量減少。亞溫快速淬火,保溫時(shí)間的延長會使Ms點(diǎn)相應(yīng)升高。對于完全馬氏體轉(zhuǎn)變,連續(xù)冷卻時(shí)過快的冷卻速度會導(dǎo)致較大的過冷度,過冷度的增加會增大馬氏體轉(zhuǎn)變體積分?jǐn)?shù),導(dǎo)致Ms點(diǎn)降低。50℃/s快速加熱至900℃并未使試樣完全奧氏體化。同時(shí)對于奧氏體這種擴(kuò)散型相變,快速加熱會使碳原子的擴(kuò)散不均勻性加重,從而使組織的不均勻化程度加深,冷卻后扔保持明顯的帶狀組織特點(diǎn)。保溫時(shí)間的延長可以緩解這種不均勻化。
[Abstract]:The rise of people's material living standards and the increasingly serious energy crisis and environmental problems put forward new and higher requirements for the automobile industry. Therefore, safety, environmental protection, energy-saving, comfort has become a hot topic and direction of automotive industry. Lightweight automobile body is one of the most effective measures to achieve energy saving and emission reduction. Research on lightweight design of automobile has become an important subject in modern automobile design and manufacture. Because the hot stamping process combines the advantages of stamping deformation and quenching, that is, the good formability of the material at high temperature and the strengthening of the phase change of the material during cooling, it can produce hot stamping parts with complete morphology, precise size and high strength. And received widespread attention. Hot stamping process parameters play an important role in sheet metal formability. In this paper, B1500HS is used as the research material and U type stamping parts as the research object. The specific research contents are: 1. 1. The effects of heating and die temperature on the microstructure and properties of different parts of U type stamping parts were studied by using the self-made mould temperature control equipment. The results showed that: for different parts of U type stamping parts, The mechanical properties and consistency are as follows: after cooling at 870 鈩，

本文編號：1824015