共查询到18条相似文献,搜索用时 111 毫秒
1.
2.
秦占江 《精密制造与自动化》1990,(1)
一、砂带磨削技术随着砂带制造水平、特别是磨料涂敷能力的提高,砂带磨削技术已经进入了全新的领域。近年来又发展研制了高效磨料锆刚玉(Zirconia alumina),因之出现了高效砂带磨削,显著地提高了砂带切削效率和砂带使用寿命,其材料切除率已经大于100mm~3/mm·s,并且每毫米宽砂带加工各种钢材,切除工件材料体积已经大大超过2000mm~3/mm,加工效率甚至超过了常规的车、铣、刨加工(图1与2),因此,砂带磨削技术的发展,方兴未艾。在美国、日本、西欧等工业发达国家都非常重视砂带磨削技术的开发与应用,因此,砂带磨削机床与 相似文献
3.
4.
5.
Y对镁合金AZ91力学性能的影响 总被引:1,自引:1,他引:1
为了找出稀土元素Y对镁合金AZ91力学性能的影响作用,从而为改善镁合金AZ91的力学性能和拓宽镁合金AZ91的应用领域提供依据,采用室温和高温拉伸试验,辅以断口分析和组织观察,对室温和150℃下不同Y含量的镁合金AZ91的抗拉强度和延伸率等力学性能进行了研究,得出了镁合金AZ91的力学性能随Y含量的变化关系.结果表明,随着稀土元素Y的增加,室温下的抗拉强度逐渐增加,延伸率略有增加;150℃下的抗拉强度逐渐增加,延伸率逐渐降低.加入适量的Y可改善镁合金AZ91的力学性能,使其满足高温下的应用要求. 相似文献
6.
7.
<正> 砂带磨削由于磨削效率高、金属切除率大、比能耗低、工艺成本低、经济效益显著而被广泛应用,发展迅速。如美国1949年到1973年间,砂带磨削机床增长了221%;在1976~1978两年间生产了砂带磨削机床32046台。而联邦德国在1963年时,砂带磨削已占磨削加工量的35%。到目前为止,已开发出砂带磨削机床数百种;开发出各种不同规格的砂带四万多种。砂带磨削的应用也已遍及机械、电子、仪器仪表、冶金、建材、汽车等部门。砂带磨削的加工精度和加工表面粗糙 相似文献
8.
为改善船用螺旋桨叶片的磨削效果,采用两种不同磨料砂带对螺旋桨叶片进行了磨削试验。讨论了砂带线速度、法向磨削压力、磨料种类对材料去除率的影响;分析了砂带粒度和接触轮硬度对表面粗糙度的影响。试验表明:使用砂带磨削螺旋桨不仅可行,并且具有较高的材料去除率,可获得较小的加工表面粗糙度。该研究为确定合理的螺旋桨砂带磨削工艺参数提供了依据。 相似文献
9.
分析了Cu-3镍铜合金砂带磨削加工过程中,砂带粒度和磨削用量的不同对磨削加工效率、工件表面质量和砂带磨损的影响。采用氧化铝磨料砂带在不同的砂带线速度或磨削压力下对镍铜合金进行了工艺试验,对材料去除量、工件表面粗糙度和砂带磨损量进行了测量。研究表明:增加砂带线速度和磨削压力可在一定程度上提高材料去除率和磨削比;随着磨削压力的增大,工件表面粗糙度呈增大趋势;随着砂带粒度的增大,工件表面粗糙度呈减小趋势;砂带线速度为25m/s,磨削压力为43N,砂带粒度为P240时,镍铜合金综合磨削效果最好。 相似文献
10.
采用高速电弧喷涂技术在AZ91镁合金表面制备了高非晶含量AlCoTi涂层,研究了涂层显微组织、力学性能、摩擦磨损及电化学腐蚀性能。结果表明,涂层呈典型的层状结构,其结构紧凑,与镁合金基体结合良好,孔隙率约为1.63%。涂层的组织主要由非晶相、纳米结构的α-Al和Al3Ti相组成。相比于AZ91镁合金,AlCoTi非晶涂层具有更高的显微硬度和耐磨性能:涂层的显微硬度约为511.3Hv0.1,远高于AZ91镁合金(62Hv0.1);在相同的磨损条件下,非晶涂层相对耐磨性约为晶体结构AZ91镁合金的3.9倍,其主要磨损机制为脆性剥落。在0.6 mol/L NaCl溶液中,非晶涂层自腐蚀电位、自腐蚀电流密度和电荷转移电阻分别为-0.696V、0.741 8μA/cm2和33 660?·cm2,明显优于AZ91镁合金的-1.392V、769.3μA/cm2和1 914?·cm2。通过对镁合金表面不同防护涂层的电化学腐蚀性能和显微硬度比较分析,本研究为镁合金提供一种低成本、高性能的涂层材料及再制造关键技术。 相似文献
11.
以主轴改造后的XK7136C数控铣床为平台,以AZ31系镁合金与7075-T651铝合金为研究对象,通过理论计算与磁场仿真,设计出适用于加工铝镁合金结构材料平面的强永磁材料磁极,并采用雾化快凝球形磁性磨粒进行试验,以验证该种光整加工方法的可行性及球形磨粒性能。使用“米字槽”与“田字槽”两种磁极分别对两种材料进行研磨实验。实验结果表明:两种端面开槽方式均可防止磨料的局部堆积,保证磨料的流动性,并使端面磁通密度增大,磁场强度梯度增大,提高研磨效率。两种磁极所研磨表面粗糙度分别为0.126 μm和0.148 μm,端面拥有更大磁通密度的“田字槽”磁极前期研磨效率更佳。 相似文献
12.
13.
Fretting wear behavior of AZ91D and AM60B magnesium alloys 总被引:2,自引:0,他引:2
The fretting wear behavior of the AZ91D and AM60B magnesium alloys are investigated using a reciprocating fretting wear machine under dry conditions with different numbers of cycles, different normal loads, slip amplitudes and frequencies. The worn surfaces and wear debris were examined using scanning electron microscopy and optical microscopy in order to understand the predominant wear mechanisms of two magnesium alloys. The results indicate that the AZ91D alloy displays a lower friction coefficient and lower wear quantity than the AM60B alloy. The AZ91D shows a higher capability than AM60B in resisting crack nucleation and propagation. Both AZ91D and AM60B show similar friction and wear characteristics. The wear quantity increases with increasing normal load, but decreases with increasing frequency. The friction coefficient also decreases as the normal load is increased. Fretting frequency had little effect on the friction coefficient. In a long term, the fatigue wear and abrasive wear were the predominant wear mechanisms for AM60B and delamination wear, adhesive wear and abrasive wear for AZ91D. 相似文献
14.
采用液压高精度材料试验机考察了平面一球面接触的AZ91D镁合金摩擦副的微动磨损行为,分析了位移幅值、法向载荷和频率等参数对摩擦因数和磨损体积的影响,考察了不同实验条件下的磨斑形貌,并探讨了其磨损机理。结果表明:AZ91D镁合金的微动区域可分为部分滑移区、混合区和滑移区3个区域,粘着磨损、疲劳磨损和磨粒磨损分别是3个区域的主要磨损机制;磨损体积随着位移幅值和法向载荷的增加而增大,但却随着频率的增大而减小。在微动部分滑移区和混合区,摩擦因数随着位移增大迅速增加;在微动滑移区,摩擦因数随法向载荷的增大而减小,而位移幅值和频率对摩擦因数的影响较小。 相似文献
15.
Improvement in tribological performances of magnesium alloy using amide compounds as lubricating additives during sliding 总被引:1,自引:0,他引:1
The tribological characteristics of a magnesium alloy, AZ91D (die-casting), are investigated in a sliding lubricating system using various amide compounds as lubricating additives on a Timken type tester against a bearing steel (AISI52100) ring. Results indicate that a significant improvement in the tribological performance exists using the amide compounds as additives. The number of amido group (–CONH2) in additive molecules and the molecular structure of amide compounds have significant effect on the tribological characteristics of magnesium alloy. Electromicroscopy reveals that the mild abrasive wear is a predominant wear mechanism of magnesium alloy using an amide additive while the dominated wear mechanism is a severe abrasive wear with severe material deformation using only base oil. Observation shows the formation of boundary film on the magnesium alloy. XPS analysis suggests the occurrence of tribo-chemical reactions between Mg and amide compounds with the formation of chemically stable compound (or complex) of magnesium and amide, as well as the formation of friction polymer. 相似文献
16.
针对镍铝青铜合金材料难以加工出仿生沟槽表面从而提高其降噪性能的问题,利用金字塔砂带和空心球砂带在镍铝青铜合金材料表面上磨削出仿生沟槽,并搭建配套试验平台来对镍铝青铜合金材料表面进行仿生沟槽结构的磨削加工。提取了磨削表面的特征,据此进行流体噪声计算,对比分析了金字塔砂带磨削出的仿生表面和空心球砂带磨削出的仿生沟槽表面的噪声性能,结果显示:金字塔砂带磨削出的规则仿生沟槽表面声学能量等级的平均值为18.07 dB,空心球砂带磨削出的不规则仿生沟槽表面声学能量等级的平均值为37.6 dB。试验中,两种砂带磨削加工后的镍铝青铜合金表面均具有仿生沟槽结构,且金字塔砂带磨削出的规则仿生沟槽表面具有更好的水下降噪性能。 相似文献
17.
基于自主研发的锂电驱动钢轨砂带打磨机和砂轮打磨机,以60N型钢轨廓形作为实验对象,全面对比了新型钢轨砂带打磨技术和传统砂轮打磨技术的性能。结果表明:当打磨压力在45~75 N范围内时,砂带打磨的材料去除率约为砂轮打磨的15~30倍,而当压力增大到90 N时,砂带打磨的材料去除率高达砂轮打磨的102倍;砂带打磨的振动加速度、噪声和能耗均小于砂轮打磨;砂带打磨切屑为带状,而砂轮打磨则表现为高温熔融状,同时当打磨压力增大到105 N时,砂轮打磨后钢轨表面会出现发蓝现象,而砂带打磨不会;此外,砂带打磨的横向表面粗糙度大于砂轮打磨,最高可达8μm,但满足中国铁路钢轨养护要求的最大值10μm。综上,钢轨砂带打磨技术在材料去除率、振动、噪声、能耗和温度等方面显著优于传统砂轮打磨技术,预期将成为工程实际中解决钢轨严重病害问题的有效方法之一。 相似文献
18.
《Wear》2006,260(1-2):140-148
The tribological characteristics of a magnesium alloy, AZ91D, were investigated in a sliding lubricating system using various N-containing compounds as lubricating additives on a Timken type tester against a bearing steel (AISI52100) ring. Results indicated that a significant improvement in the tribological performance exists using N-containing compounds as additives. The characteristics of anti-wear, anti friction and load-carrying capacity increased with an increase in the number of amidogen groups in amine molecules. Antiwear and antifriction characteristics were also observed with an increase in the length of the carbon chain in amide compounds. The amide showed a much better performance than the amine in terms of the tribological characteristics of the magnesium alloy. Electromicroscopy revealed that mild abrasive wear was a predominant wear mechanism of the magnesium alloy using an amine (or amide) additive; while the dominant wear mechanism was severe abrasive wear with severe material deformation using only base oil. Analysis showed the formation of a boundary film on the magnesium alloy. XPS analysis suggested the occurrence of tribo-chemical reactions between Mg and N-containing compounds with the formation of a chemically stable complex of magnesium and amine (or amide), as well as the formation of friction polymer. 相似文献