本文關(guān)鍵詞： 電工鋼 斜刃橫剪 剪切間隙 邊緣損傷 晶粒尺寸　出處：《廣東工業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：本文基于斜刃橫剪加工實(shí)驗(yàn),研究了不同工藝條件對(duì)電工鋼板材剪切斷面毛刺、邊緣硬化、磁性能等損傷規(guī)律,發(fā)現(xiàn)對(duì)0.23mm取向電工鋼,當(dāng)相對(duì)間隙(間隙板厚比c/t%)在4.3%~6.5%,斷面質(zhì)量相對(duì)較好,邊緣損傷程度也較低。由于其晶粒沿軋制方向取向的特殊性,磁性能表現(xiàn)出各向異性,越靠近軋制方向磁性能越好。對(duì)無取向電工鋼,0.35mm板在相對(duì)間隙4.3%~5.7%,剪切帶和斷裂帶高度變化幅度較小,損傷程度相對(duì)較低。對(duì)0.5mm和0.65mm板,除在較小間隙外,在適當(dāng)?shù)拈g隙范圍5%~7%,也能獲得相對(duì)較好的剪切斷面,邊緣硬化,磁性能損耗均較小。上述四種板厚的最大硬化影響區(qū)達(dá)600μm,且硬化不均勻,截面和板面兩個(gè)方向的硬化影響深度基本一致,另外隨剪切條數(shù)增加,剪切邊緣損傷區(qū)域增多,磁性能越惡化,而剪切速度對(duì)斷面質(zhì)量影響不大。研究發(fā)現(xiàn)隨剪切間隙變化,各板材的剪切斷面形貌、毛刺、剪切邊緣硬化以及磁性能損傷之間具有較一致的對(duì)應(yīng)規(guī)律,建立了不同間隙剪切后宏觀毛刺與微觀損傷之間的相關(guān)性。對(duì)于取向和無取向電工鋼,其區(qū)別不僅在于晶粒取向有無方向性,更重要的是不同板厚以及晶粒尺寸決定了其剪切性能的差異,板厚越薄,其晶粒尺寸越大,相應(yīng)的抗剪能力越弱,也需考慮不同剪切間隙對(duì)變形的影響。利用XRD對(duì)不同間隙剪切樣品進(jìn)行織構(gòu)分析表明,在相對(duì)較小和較大間隙時(shí)織構(gòu)成分的含量對(duì)磁性能均不利,而處在中間的適當(dāng)間隙時(shí)則表現(xiàn)出較好的織構(gòu)質(zhì)量,通過主成分分析進(jìn)一步說明了隨相對(duì)間隙變化,鐵損、矯頑力與織構(gòu)含量的變化存在可靠的線性關(guān)系。根據(jù)不同板厚的微觀組織觀察,引入尺寸效應(yīng)因子λ=t/d,考慮不同板厚與晶粒尺寸的比值下材料變形的區(qū)別,進(jìn)而建立側(cè)向間隙與晶粒尺寸的關(guān)系模型,結(jié)合多晶材料的塑性變形理論分析了c/d1、c/d≈1、c/d1三種情況下材料變形的區(qū)別,進(jìn)一步通過剪切邊緣微觀組織以及不同側(cè)隙下剪切的受力情況分析,對(duì)上述模型進(jìn)行驗(yàn)證,發(fā)現(xiàn)斷面的塌角、剪切帶、斷裂帶和毛刺的形成與材料的晶粒尺寸以及側(cè)向間隙、板厚關(guān)系密切,通過c/d以及t/d的比值可以發(fā)現(xiàn)不同比值下,材料發(fā)生了不同的力學(xué)行為,從而導(dǎo)致了材料產(chǎn)生了不同的宏觀斷面,相應(yīng)地影響了組織變形的程度,進(jìn)而決定了剪切邊緣硬化及磁性能損傷的程度。以剪切邊緣磁疇結(jié)構(gòu)觀察為基礎(chǔ),通過納米壓痕法研究殘余應(yīng)力對(duì)磁疇結(jié)構(gòu)的影響,發(fā)現(xiàn)剪切邊緣磁疇改變與殘余應(yīng)力的分布具有較好的對(duì)應(yīng)關(guān)系,殘余應(yīng)力不僅對(duì)磁疇寬度產(chǎn)生影響,更為重要的是改變了磁疇的形態(tài)。依據(jù)剪切邊緣微觀組織觀察,建立了組織變形與取向變化關(guān)系模型,通過XRD檢測分析,發(fā)現(xiàn)剪切在很大程度上影響了晶粒取向的改變,進(jìn)一步研究發(fā)現(xiàn)晶粒取向隨變形量的衍變主要由形核位置的改變而引起的,在不同的側(cè)隙條件下形核位置的改變以及應(yīng)力的共同作用引起了組織晶粒取向、織構(gòu)的衍變,進(jìn)而影響了磁性能。
[Abstract]:The oblique edge shear processing based on experiments of hardened edge of different technological conditions on the electrical steel sheet shearing section, burr, magnetic properties and other damage law, found on 0.23mm oriented electrical steel, when the relative gap (the gap thickness ratio c/t%) in the 4.3%~6.5% section, quality is relatively good, edge damage degree is also lower due. The particularity of the grain orientation along the rolling direction, magnetic properties exhibit anisotropy, the more close to the rolling direction better. Magnetic properties of non oriented electrical steel plate, 0.35mm in the relative gap 4.3%~5.7%, shear zone and fracture zone height variation amplitude is smaller, the damage degree is relatively low. The 0.5mm and 0.65mm board, except in small clearance, clearance in the appropriate scope of the 5%~7%, also can obtain relatively good edge shearing section, hardening, magnetic loss was small. The largest area of the four kinds of hardening effect of plate thickness up to 600 m, and the hardening is not uniform, and the cross section The surface hardening effect of the two directions of the depth is consistent with the shear number also increased, the shear edge damage area increases and the magnetic properties worse, while the shear velocity has little effect on the quality of cross section. The study found that changes with the shear gap, shear fracture morphology, the sheet shearing edge burrs, hardening and magnetic properties with corresponding rules more consistent damage, the correlation between macro and micro burr damage is established. For different gap shear oriented and non oriented electrical steel, the distinction is not only there is no direction of grain orientation, more important is the different thickness and grain size determines the difference between the shear performance of the plate thickness is thin, the increase of the grain size, the corresponding shear capacity is weak, also need to consider the effect of shear deformation. The gap of different gap shear sample texture analysis indicated that the use of XRD, in a relatively small And a larger gap when the texture components content on the magnetic properties were negative, while in the middle of the proper clearance when the show texture of good quality, through principal component analysis further illustrates the changes with the relative gap of iron loss, there are linear relationship between the change of coercivity and reliable texture content. Based on the observation of the microstructure of different plate the thickness, size effect factor =t/d, considering the difference between the material deformation ratio of different thickness and grain size, and then establish the relationship model of lateral clearance and grain size, combined with the theory of plastic deformation of c/d1 polycrystalline materials, c/d = 1, the difference between material deformation of c/d1 under three conditions through further analysis of microstructure and shear edge stress under different shear clearance, to verify the model, found that section of the collapse angle, shear zone, fault zone and the formation of grain size and material of the burr Inch plate thickness and lateral clearance, close by c/d and the ratio of t/d can be found in different ratio, the mechanical behavior of different materials, resulting in material produced macrosection different, the corresponding impact on the organization degree of deformation, and then determine the cutting edge hardening and magnetic properties of the extent of the damage. In order to observe the shear edge domain structure based on nano indentation method by residual stress effect on domain structure, distribution of shear edge domain change and residual stress has a good corresponding relationship, the residual stress not only affects the domain width, more important is to change the domain morphology based on the shear. The edge of the microstructure observation, established tissue deformation and orientation change relation model, through XRD analysis, we find that the shear effect of grain orientation change to a great extent, further research It is found that the evolution of grain orientation with deformation is mainly caused by the change of nucleation location. Under different backlash conditions, the change of nucleation location and the interaction of stress cause the evolution of grain orientation and texture, and further affect the magnetic properties.

【學(xué)位授予單位】：廣東工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TG142.1

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