【摘要】：鍛件內(nèi)部微觀組織均勻性是決定鍛件綜合力學(xué)性能的重要因素。大型鍛件的生產(chǎn)過程主要包括鍛造和熱處理等重要環(huán)節(jié),鍛造成形通常采用自由鍛工藝。自由鍛具有鍛造工藝冗長、局部變形、不連續(xù)變形等特點(diǎn),導(dǎo)致鍛件變形和溫度的不均勻,從而引起鍛件內(nèi)部微觀組織不均勻,增大后續(xù)熱處理的難度。因此,研究大型鍛件在鍛造過程中變形均勻性和微觀組織演變規(guī)律,對(duì)提高鍛件組織均勻性,為鍛后熱處理做準(zhǔn)備具有重要意義。以鍛態(tài)30Cr2Ni4MoV鋼為研究對(duì)象,利用Gleeble-1500D熱/力模擬試驗(yàn)機(jī),使用雙道次熱壓縮的方法,在變形溫度為900~1000oC、應(yīng)變速率為0.01~1s-1、道次間隔時(shí)間為5~60s的實(shí)驗(yàn)條件下,研究其高溫變形時(shí)的靜態(tài)再結(jié)晶行為,繪制出應(yīng)力—應(yīng)變曲線,并采用2%的補(bǔ)償法確定了靜態(tài)再結(jié)晶體積分?jǐn)?shù),討論了不同變形參數(shù)對(duì)其靜態(tài)再結(jié)晶的影響。根據(jù)實(shí)驗(yàn)結(jié)果,建立了鍛態(tài)30Cr2Ni4MoV鋼靜態(tài)再結(jié)晶動(dòng)力學(xué)模型和再結(jié)晶晶粒尺寸模型。利用DEFORM-3D軟件,分析了上平下V型砧的拔長變形過程中,應(yīng)變、溫度、靜態(tài)再結(jié)晶體積分?jǐn)?shù)、動(dòng)態(tài)再結(jié)晶體積分?jǐn)?shù)以及晶粒分布規(guī)律,并結(jié)合縮比實(shí)驗(yàn)對(duì)模擬結(jié)果和實(shí)驗(yàn)結(jié)果進(jìn)行比較、分析,得到當(dāng)鍛比在1.1~1.3、鍛造溫度在1050~1250℃范圍內(nèi),隨著鍛比和鍛造溫度的增大,變形和晶粒的不均勻程度增加。
[Abstract]:The internal microstructure uniformity of forgings is an important factor to determine the comprehensive mechanical properties of forgings. The production process of large forgings mainly includes forging and heat treatment. Free forging has the characteristics of long forging process, local deformation and discontinuous deformation, which leads to the inhomogeneity of forging deformation and temperature, which causes the internal microstructure of forging to be uneven and increases the difficulty of subsequent heat treatment. Therefore, it is of great significance to study the deformation uniformity and microstructure evolution of large forgings in the process of forging, so as to improve the microstructure uniformity of forgings and prepare for post-forging heat treatment. Taking forged 30Cr2Ni4MoV steel as the research object, using Gleeble-1500D thermal / force simulation testing machine, the method of double pass thermal compression was used. Under the experimental conditions of deformation temperature of 900,1000oC, strain rate of 0.01g / 1s-1s and interval time of 5s / 60s, the strain rate was 0.01oC, and the interval time was 50s. The static recrystallization behavior during high temperature deformation is studied and the stress-strain curve is drawn. The integral number of the static recrystallization volume is determined by the compensation method of 2%. The influence of different deformation parameters on the static recrystallization is discussed. Based on the experimental results, the static recrystallization kinetics model and recrystallization grain size model of forged 30Cr2Ni4MoV steel were established. By using DEFORM-3D software, the strain, temperature, static recrystallization volume integral number, dynamic recrystallization volume integral number and grain distribution law during pull-out deformation of upper-flat-down V-shaped anvil are analyzed. By comparing the simulation results with the experimental results, it is found that when the forging ratio is 1.1 ~ 1.3and the forging temperature is 1050 ~ 1250 鈩，

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