硼鋼B1500HS激光焊接接頭組織及力學(xué)性能研究
發(fā)布時(shí)間：2018-12-19 13:40
【摘要】：熱沖壓硼鋼具有超高的強(qiáng)度,不僅能增加車身的安全性能,而且能降低車身重量。激光焊接具有焊接質(zhì)量好、效率高、自動(dòng)化程度高等優(yōu)點(diǎn),目前在汽車工業(yè)中得到了廣泛應(yīng)用。因此,研究熱沖壓硼鋼的激光焊接技術(shù)對(duì)該種鋼在汽車工業(yè)的應(yīng)用具有重要的理論意義和工程應(yīng)用價(jià)值。本文以寶鋼生產(chǎn)的熱沖壓硼鋼B1500HS為研究對(duì)象,采用有限元分析的方法進(jìn)行焊接工藝參數(shù)的初步優(yōu)選,并用材料性能模擬軟件研究不同焊接工藝參數(shù)對(duì)焊接接頭組織和力學(xué)性能的影響。之后進(jìn)行激光對(duì)接焊和激光搭接焊試驗(yàn),研究不同焊接工藝參數(shù)對(duì)接頭組織和力學(xué)性能的影響。焊接工藝參數(shù)優(yōu)選的模擬結(jié)果表明,熱輸入相同時(shí),高功率、高焊速焊接相對(duì)于低功率、低焊速焊接能夠增加熱影響區(qū)的冷卻速度,減少軟化區(qū)的回火時(shí)間。接頭組織和力學(xué)性能的模擬結(jié)果表明,焊縫區(qū)、完全淬火區(qū)為馬氏體組織,軟化區(qū)有M3C型碳化物析出。焊接速度對(duì)焊縫區(qū)、完全淬火區(qū)的組織和力學(xué)性能影響較小。焊縫區(qū)和完全淬火區(qū)的硬度、強(qiáng)度與母材相當(dāng)。軟化區(qū)的硬度和強(qiáng)度隨回火溫度和回火時(shí)間的增加而降低。焊接速度越小,軟化區(qū)的硬度和強(qiáng)度也越低。硼鋼B1500HS激光對(duì)接焊試驗(yàn)結(jié)果表明,焊縫、完全淬火區(qū)都是馬氏體組織,不完全淬火區(qū)為馬氏體加鐵素體組織,軟化區(qū)為回火馬氏體加鐵素體組織。焊接接頭的硬度分布不均勻,在軟化區(qū)硬度明顯降低。拉伸試樣都斷裂在軟化區(qū)。焊接接頭的抗拉強(qiáng)度隨著焊接速度增加而增加,三點(diǎn)彎曲試驗(yàn)試樣的最大彎曲角度隨著焊接速度的增加而減小。脈沖頻率對(duì)焊接接頭的抗拉強(qiáng)度影響較小,氧化皮會(huì)降低焊接接頭的抗拉強(qiáng)度。當(dāng)焊接功率為1000W,焊接速度在10mm/s-15mm/s范圍內(nèi)時(shí),接頭抗拉強(qiáng)度和抗彎強(qiáng)度都在1100MPa以上,最大彎曲角度為180°,焊接接頭具有良好力學(xué)性能。硼鋼B1500HS激光搭接焊時(shí),焊縫中出現(xiàn)了小孔型氣孔。焊接接頭組織和硬度的變化規(guī)律與對(duì)接焊相似。焊接接頭軟化區(qū)馬氏體分解更嚴(yán)重,該區(qū)的硬度更低。搭接接頭拉伸斷裂發(fā)生在搭接面處,接頭的最大抗剪力隨著焊接速度的增加而減小。脈沖頻率對(duì)激光對(duì)接焊接頭強(qiáng)度影響很小,對(duì)搭接接頭的氣孔率和接頭最大抗剪力有明顯影響。硼鋼上表面的氧化皮能增加材料對(duì)激光的吸收效率,使得焊縫尺寸增加。相同焊接工藝參數(shù)下,氧化皮降低了對(duì)接接頭的強(qiáng)度,但增加了搭接接頭的最大抗剪力。
[Abstract]:Hot stamping boron steel has high strength, which can not only increase the safety performance of the body, but also reduce the weight of the body. Laser welding has the advantages of good welding quality, high efficiency and high degree of automation, so it has been widely used in automobile industry. Therefore, the study of laser welding technology of hot stamping boron steel has important theoretical significance and engineering application value for the application of this kind of steel in automobile industry. In this paper, the hot stamping boron steel B1500HS produced by Baosteel is taken as the research object and the method of finite element analysis is used to optimize the welding process parameters. The effects of different welding parameters on the microstructure and mechanical properties of welded joints were studied by means of material performance simulation software. Then laser butt welding and laser lap welding experiments were carried out to study the effect of different welding parameters on the microstructure and mechanical properties of the joints. The simulation results of optimum selection of welding process parameters show that when the heat input is the same, the high power and high welding speed welding can increase the cooling rate of the heat affected zone and reduce the tempering time of the softening zone compared with the low power welding. The simulation results of the microstructure and mechanical properties of the joints show that the weld zone and the complete quenching zone are martensite, and the M 3C carbide precipitates in the softening zone. The welding speed has little effect on the microstructure and mechanical properties of the weld zone and the complete quenching zone. The hardness and strength of weld zone and complete quenching zone are similar to that of base metal. The hardness and strength of softening zone decrease with the increase of tempering temperature and tempering time. The lower the welding speed, the lower the hardness and strength of softening zone. The results of B1500HS laser butt welding of boron steel show that the weld and complete quenching zone are martensite structure, the incomplete quenching zone is martensite plus ferrite structure, and the softening zone is tempered martensite and ferrite structure. The hardness distribution of the welded joints is not uniform, and the hardness decreases obviously in the softening zone. The tensile specimens are fractured in the softening zone. The tensile strength of welded joint increases with the increase of welding speed, and the maximum bending angle of three-point bending test sample decreases with the increase of welding speed. The pulse frequency has little effect on the tensile strength of welded joints, and the oxide coating will decrease the tensile strength of welded joints. When the welding power is 1000W and the welding speed is within the range of 10mm/s-15mm/s, the tensile strength and bending strength of the joint are above 1100MPa and the maximum bending angle is 180 擄. The welded joint has good mechanical properties. In the B1500HS laser lap welding of boron steel, there are small pore holes in the weld. The variation of microstructure and hardness of welded joints is similar to that of butt welding. Martensite decomposition is more serious and hardness is lower in the softening zone of welded joint. The tensile fracture of the lap joint occurs at the lap joint, and the maximum shear strength decreases with the increase of the welding speed. The pulse frequency has little effect on the strength of laser butt welding joint, but has obvious influence on the porosity and the maximum shear resistance of the lap joint. The oxide coating on the upper surface of boron steel can increase the laser absorption efficiency of the material and increase the weld size. Under the same welding parameters, the oxide coating decreases the strength of the butt joint, but increases the maximum shear strength of the lap joint.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TG456.7
本文編號(hào)：2387001
[Abstract]:Hot stamping boron steel has high strength, which can not only increase the safety performance of the body, but also reduce the weight of the body. Laser welding has the advantages of good welding quality, high efficiency and high degree of automation, so it has been widely used in automobile industry. Therefore, the study of laser welding technology of hot stamping boron steel has important theoretical significance and engineering application value for the application of this kind of steel in automobile industry. In this paper, the hot stamping boron steel B1500HS produced by Baosteel is taken as the research object and the method of finite element analysis is used to optimize the welding process parameters. The effects of different welding parameters on the microstructure and mechanical properties of welded joints were studied by means of material performance simulation software. Then laser butt welding and laser lap welding experiments were carried out to study the effect of different welding parameters on the microstructure and mechanical properties of the joints. The simulation results of optimum selection of welding process parameters show that when the heat input is the same, the high power and high welding speed welding can increase the cooling rate of the heat affected zone and reduce the tempering time of the softening zone compared with the low power welding. The simulation results of the microstructure and mechanical properties of the joints show that the weld zone and the complete quenching zone are martensite, and the M 3C carbide precipitates in the softening zone. The welding speed has little effect on the microstructure and mechanical properties of the weld zone and the complete quenching zone. The hardness and strength of weld zone and complete quenching zone are similar to that of base metal. The hardness and strength of softening zone decrease with the increase of tempering temperature and tempering time. The lower the welding speed, the lower the hardness and strength of softening zone. The results of B1500HS laser butt welding of boron steel show that the weld and complete quenching zone are martensite structure, the incomplete quenching zone is martensite plus ferrite structure, and the softening zone is tempered martensite and ferrite structure. The hardness distribution of the welded joints is not uniform, and the hardness decreases obviously in the softening zone. The tensile specimens are fractured in the softening zone. The tensile strength of welded joint increases with the increase of welding speed, and the maximum bending angle of three-point bending test sample decreases with the increase of welding speed. The pulse frequency has little effect on the tensile strength of welded joints, and the oxide coating will decrease the tensile strength of welded joints. When the welding power is 1000W and the welding speed is within the range of 10mm/s-15mm/s, the tensile strength and bending strength of the joint are above 1100MPa and the maximum bending angle is 180 擄. The welded joint has good mechanical properties. In the B1500HS laser lap welding of boron steel, there are small pore holes in the weld. The variation of microstructure and hardness of welded joints is similar to that of butt welding. Martensite decomposition is more serious and hardness is lower in the softening zone of welded joint. The tensile fracture of the lap joint occurs at the lap joint, and the maximum shear strength decreases with the increase of the welding speed. The pulse frequency has little effect on the strength of laser butt welding joint, but has obvious influence on the porosity and the maximum shear resistance of the lap joint. The oxide coating on the upper surface of boron steel can increase the laser absorption efficiency of the material and increase the weld size. Under the same welding parameters, the oxide coating decreases the strength of the butt joint, but increases the maximum shear strength of the lap joint.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TG456.7
【共引文獻(xiàn)】
相關(guān)期刊論文 前10條
1 胡敏英;吳志生;趙菲;殷瑞峰;;鋁合金激光焊接的工藝特點(diǎn)及發(fā)展現(xiàn)狀[J];熱加工工藝;2007年15期
2 顧春影;陳根余;梅麗芳;蔡興;;車身零部件的激光搭接焊與電阻點(diǎn)焊對(duì)比分析[J];熱加工工藝;2011年17期
3 劉超;王磊;劉楊;;汽車用先進(jìn)高強(qiáng)鋼的發(fā)展及其在車身設(shè)計(jì)中的應(yīng)用[J];特鋼技術(shù);2012年02期
4 劉超;王磊;劉楊;;應(yīng)變速率對(duì)Q&P鋼拉伸變形行為的影響[J];特鋼技術(shù);2012年03期
5 孫彩娜;張梅;邵光杰;張恒華;;高強(qiáng)度22MnB5鋼板加熱過(guò)程中組織演變規(guī)律的研究[J];上海金屬;2013年02期
6 朱宏偉;張濤;;激光焊接技術(shù)在汽車制造中的應(yīng)用[J];企業(yè)導(dǎo)報(bào);2013年11期
7 賀長(zhǎng)林;張弓;王映品;陳賢帥;陳少克;;激光輔助加工與熱處理在汽車關(guān)鍵零件加工中的應(yīng)用綜述[J];熱加工工藝;2014年08期
8 閻石;辛志強(qiáng);齊寶欣;楊璐;閻寒;;爆炸與火災(zāi)聯(lián)合作用下結(jié)構(gòu)鋼動(dòng)態(tài)本構(gòu)關(guān)系[J];沈陽(yáng)建筑大學(xué)學(xué)報(bào)(自然科學(xué)版);2014年04期
9 龔濤;鐘如濤;王輝;林承江;黃治軍;;600MPa級(jí)高Al冷軋雙相鋼激光焊接性能研究[J];熱加工工藝;2014年23期
10 王廣勇;;車身焊接技術(shù)現(xiàn)狀及發(fā)展趨勢(shì)[J];汽車工藝與材料;2015年03期
，本文編號(hào)：2387001
本文鏈接：http://sikaile.net/kejilunwen/jinshugongy/2387001.html
最近更新
教材專著
