【摘要】：30CrMnSiNi2A超高強(qiáng)度鋼螺紋件在加工和熱處理過(guò)程中,易在螺紋部位形成應(yīng)力集中,需要對(duì)螺栓類(lèi)制件的螺紋和退刀槽等部位進(jìn)行局部回火處理。工件局部回火處理中使用高頻感應(yīng)加熱取代落后的鉛浴回火工藝已經(jīng)成為發(fā)展趨勢(shì)。通過(guò)數(shù)值模擬和實(shí)驗(yàn)相結(jié)合的方法確定30CrMnSiNi2A螺紋件感應(yīng)局部回火工藝參數(shù),對(duì)于使用綠色環(huán)保、高效率的感應(yīng)加熱系統(tǒng)替代落后的傳統(tǒng)鉛浴回火工藝以及獲得高綜合使用性能的30CrMnSiNi2A螺紋件具有十分重要的意義。本文從30CrMnSi Ni2A螺紋件感應(yīng)加熱過(guò)程電磁-溫度場(chǎng)數(shù)值模擬研究入手,建立了適合30CrMnSiNi2A螺紋件感應(yīng)加熱局部回火過(guò)程的數(shù)值計(jì)算模型,研究了各工藝參數(shù)對(duì)30CrMnSiNi2A鋼制件感應(yīng)加熱影響規(guī)律,并且進(jìn)行了30CrMnSiNi2A鋼小型螺紋類(lèi)工件局部回火感應(yīng)線圈的優(yōu)化設(shè)計(jì),并結(jié)合感應(yīng)加熱工藝參數(shù)和30CrMnSiNi2A鋼材料組織性能之間的關(guān)系,最終確定了30CrMnSiNi2A鋼螺紋類(lèi)工件感應(yīng)局部回火的工藝參數(shù)。根據(jù)實(shí)驗(yàn)分析,得出以下結(jié)論:(1)30CrMnSiNi2A鋼工件感應(yīng)加熱建模分析,包括實(shí)體模型的建立,30CrMnSiNi2A材料的熱物性參數(shù)模型,實(shí)體模型的網(wǎng)格劃分,邊界載荷條件的設(shè)置以及加載求解。數(shù)值模擬結(jié)果和實(shí)際測(cè)量結(jié)果比較發(fā)現(xiàn),數(shù)值模擬結(jié)果和實(shí)驗(yàn)結(jié)果相近,對(duì)實(shí)際操作具有一定的指導(dǎo)意義。(2)感應(yīng)加熱過(guò)程中,工件表面溫度迅速達(dá)到相變溫度,在相變點(diǎn)維持一段穩(wěn)定后工件的溫度曲線呈現(xiàn)不同的趨勢(shì);電流密度值正相關(guān)于感應(yīng)磁場(chǎng)強(qiáng)度值大小,從而直接影響最終加熱溫度;電流頻率會(huì)影響材料的透入深度,進(jìn)而影響軸件感應(yīng)加熱后的心表溫差。高頻率能在極短時(shí)間內(nèi)迅速提高材料表面溫度,同時(shí)提高熱效率,但高頻階段頻率的增大產(chǎn)生影響越來(lái)越不明顯,故而頻率選擇需要綜合考慮;線圈厚度對(duì)感應(yīng)溫度的影響同電流密度相同,線圈壁厚的設(shè)計(jì)主要從感應(yīng)器的功率損耗和經(jīng)濟(jì)方面考慮。(3)進(jìn)行30CrMnSiNi2A螺紋件局部回火感應(yīng)線圈進(jìn)行了優(yōu)化設(shè)計(jì),得到的優(yōu)化線圈為:感應(yīng)線圈截面為矩形,矩形截面尺寸12×6 mm,線圈壁厚為1 mm,線圈內(nèi)徑為?20 mm,匝數(shù)為2,線圈1的位置因素7)1為34.5 mm,線圈2的位置因素7)2為64 mm,兩線圈的間距為5.5 mm。(4)30CrMnSiNi2A鋼材料組織性能與感應(yīng)加熱工藝參數(shù)關(guān)系研究結(jié)果表明:鉛浴回火和感應(yīng)回火式樣基體組織形貌基本一致,其組織都是保持著回火馬氏體的板條形貌,且板條上存在著碳化物析出,這為感應(yīng)局部回火代替鉛浴回火提供了組織可能;硬度分析表明,工件表面最大溫度決定徑向硬度分布,且表面溫度范圍在450℃-550℃間,硬度分布符合工藝要求;適當(dāng)?shù)谋?保溫時(shí)間1-5 s)可以優(yōu)化徑向硬度分布。本文中,所選取的30CrMnSiNi2A螺紋件局部回火工藝參數(shù)為:電流頻率f=120KHZ,電流密度Js=25 e6A m2?,加熱時(shí)間為3 s,保溫時(shí)間1-5 s。
[Abstract]:During the process of processing and heat treatment of 30CrMnSiNi2A ultra-high strength steel thread parts, the stress concentration is easily formed in the thread parts. It has become a trend to replace the backward lead bath tempering process with high frequency induction heating in the partial tempering of workpiece. The parameters of 30CrMnSiNi2A thread parts are determined by the combination of numerical simulation and experiment. It is very important to replace the traditional lead bath tempering technology with high efficiency induction heating system and to obtain 30CrMnSiNi2A thread parts with high comprehensive performance. In this paper, starting with the numerical simulation of electromagnetic temperature field of 30CrMnSiNi2A thread parts, a numerical calculation model suitable for the local tempering process of 30CrMnSiNi2A thread parts by induction heating is established. The influence of various process parameters on induction heating of 30CrMnSiNi2A steel was studied, and the optimum design of local tempering induction coil of 30CrMnSiNi2A steel small thread workpiece was carried out, and the relationship between the parameters of induction heating process and the microstructure and properties of 30CrMnSiNi2A steel material was also studied. Finally, the process parameters of induction partial tempering of 30CrMnSiNi2A steel thread workpiece are determined. Based on the experimental analysis, the following conclusions are obtained: (1) the modeling and analysis of the induction heating of 30CrMnSiNi2A steel workpiece, including the establishment of solid model, the thermo-physical parameter model of 30CrMnSiNi2A material, the mesh division of the solid model, the setting of boundary load conditions and the solution of loading. It is found that the numerical simulation results are similar to the experimental results, which has a certain guiding significance for practical operation. (2) during the induction heating process, the surface temperature of the workpiece reaches phase transition temperature rapidly. After maintaining a stable phase transition point, the temperature curve of the workpiece shows a different trend; the current density value is positively related to the magnitude of the inductive magnetic field intensity, which directly affects the final heating temperature; the current frequency will affect the penetration depth of the material. Furthermore, the temperature difference of the core after induction heating is affected. The high frequency can increase the surface temperature of the material and the thermal efficiency in a very short time, but the influence of the increase of the frequency in the high frequency stage is less and less obvious, so the choice of the frequency needs to be considered synthetically. The effect of coil thickness on induction temperature is the same as that of current density. The design of coil wall thickness is mainly considered from the power loss and economy of the inductor. (3) the local tempering induction coil of 30CrMnSiNi2A thread is optimized. The optimized coil is: the section of induction coil is rectangular, Rectangular section size 12 脳 6 mm, coil wall thickness 1 mm, coil inner diameter 20 mm, turn number 2, coil 1 position factor 7) 1 34.5 mm, coil 2 position factor 7) 2 64 mm, distance between two coils 5.5 mm. (4) Microstructure, properties and induction addition of 30CrMnSiNi2A steel The results of the study on the relationship of thermal process parameters show that the microstructure of the matrix is basically the same as that of the lead bath tempering and induction tempering. The microstructure of all of them is to maintain the lath morphology of tempered martensite, and the carbides precipitate on the lath, which provides the possibility for inductive partial tempering instead of lead bath tempering, and hardness analysis shows that, The maximum surface temperature of the workpiece determines the radial hardness distribution, and the surface temperature ranges from 450 鈩，

本文編號(hào)：2131590