Reduction of friction in compression of plates by load pulsation

To prevent a sharp rise in load in compression of plates, a compression process using load pulsation was developed. In this process, the compression load is partially released during the forming to re-lubricate the surfaces of the plate. Gaps on the outer surfaces of the plate were caused in each release of unload by the difference in elastic recovery between the die and the plate, and the liquid lubricant is automatically fed into the gap. In the compression of an aluminium alloy plate, the effects of the releasing ratio of the load and the number of release on the reduction in compressive load were examined. Compressive load was considerably reduced by the load pulsation, and the thickness of the compressed plate was decreased. The occurrence of the gaps in the partial release of load was verified by corroding the surfaces of the plate in a compression experiment. It was found that the load pulsation having the automatic re-lubrication function is effective in preventing the increase in the load in the compression of plates.     

不锈钢锻造用玻璃防护润滑剂

玻璃防护润滑剂是降低锻压过程中锻件与模具的摩擦、防止锻件表面氧化和合金元素贫化、同时隔离锻件与模具之间热传导的独特工艺材料.本文采用复合玻璃的设计思想,研制出了在850～1180℃温度范围内不锈钢锻造用玻璃防护润滑剂.采用试烧法研究了复合玻璃润滑剂随温度的变化规律;根据不锈钢材料锻造加热条件,测试了玻璃润滑剂在金属坯料表面的防护性能,并对复合玻璃润滑在不锈钢锻造变形时的润滑机理进行了分析.     

2205双相不锈钢锻造失效分析

针对2205双相不锈钢在实际工业化生产中出现的锻造失效问题进行了研究。采用10 t EAF-AOD双联工艺冶炼2205双相不锈钢,浇注2支4.2 t钢锭。钢锭化学成分合格,表面质量良好,但在锻造开坯过程中,钢锭表面出现大量横向裂纹,导致锻件产品报废。利用金相显微镜、扫描电镜以及能谱分析仪等,对2205双相不锈钢在锻造过程中出现的裂纹缺陷进行金相组织、截面形貌及能谱分析。结果表明:2205双相不锈钢锻造失效主要原因是,锻前加热过程中,在850℃进行了时效处理,析出大量σ脆性相,导致钢的塑韧性急剧下降,受到变形力作用后表面严重开裂;热加工过程中,2205双相不锈钢在600~1000℃温度范围内应快速升温,不宜做时效处理,避免σ相析出,恶化钢的力学性能。     

1Cr18Ni9Ti不锈钢筒形件拉深工艺

介绍了不锈钢筒形件拉深时,合理改变拉深凸、凹模间隙,采用新的润滑剂和润滑方法,在取消或改变热处理工序的情况下,拉深出表面质量理想的不锈钢筒形件。     

Microstructure and antibacterial property of stainless steel implanted by Cu ions

Copper ions were implanted into AISI 304 austenitic stainless steel by metal vapor vacuum are (MEVVA) with 60 - 100 keV energy and a dose range (0.2 - 5.0) × 1017 cm-2. Then Cu-implanted stainless steel was treated by a special antibacterial treatment. Antibacterial rates of Cu-implanted stainless steel, Cu-implanted stainless steel with special antibacterial treatment and un-implanted stainless steel were obtained by agar plate method. Phase composition in the implanted layer was analyzed by glancing X-ray diffraction (GXRD). Microstructure of antibacterial stainless steel was observed with transmission electron microscopy (TEM), and changes of the bacterium appearance after 24 h antibacterial action on the surface of un-implanted and Cu-implanted stainless steel with antibacterial treatment were observed with bio-TEM respectively. The results show that stainless steel obtains antibacterial property against E. coli when the Cu ions dose approaches to the saturated one. A suitable amount of Cu-rich phase uniformly disperses on the surface of Cu-implanted stainless steel that is treated by the special antibacterial treatment. The Cu-rich phase naked on the surface has a function of damage to pericellular membrane and cell wall,the pericellular membrane is thickened and the karyon degraded, and finally, bacteria die. Cu-rich phase naked on the surface endows stainless steel with best antibacterial property.     

A novel surface texture for magnetic fluid lubrication

Magnetic fluid has many advantages when serving as lubricant. With an appropriate magnetic field this lubricant can prevent leakage and increase the load capacity of lubricant film. It can also be fixed at the friction zone by applying an external magnetic field. A novel design of magnetic fluid lubrication with magnetic surface texture was proposed in this paper. A micro-scale dimple pattern was firstly fabricated on the surface of tribo-pair and then a permanent magnet material was electrodeposited into these dimples, so that there are both geometric surface texture and periodic distribution of magnetic field on the surface (magnetic surface texture). In this paper, CoNiMnP permanent magnetic film (about 25 μm thickness) was electrodeposited into micro-dimples (500 μm in diameter) on the surface of 316 stainless steel. The impact of magnetic surface texture on lubrication was investigated using a pin-on-disk test rig. The test results showed that magnetic surface texture was conducive to form effective lubrication at low sliding velocity when lubricated by magnetic fluids.     

Wear characteristics of ultrahigh molecular weight polyethylene (UHMWPE)

The wear of ultrahigh molecular weight polyethylene (UHMWPE) bearing against 316 stainless steel or cobalt chromium (Co-Cr) alloy was measured using a 12-channel wear tester especially developed for the evaluation of candidate materials for prosthetic joints. The coefficient of friction and wear rate were determined as a function of lubricant, contact stress, and metallic surface roughness in tests lasting 2–3 million cycles, the equivalent of several years use of a prosthesis. Wear was determined by the weight loss of the polyethylene (PE) specimens corrected for the effect of fluid absorption. The friction and wear processes in blood serum differed markedly from those in saline solution or distilled water. Only serum lubrication produced wear surfaces resembling those observed on removed prostheses. The experimental methods provided accurate reproducible measurement of PE wear. The long-term wear rates were proportional to load and sliding distance. Although the PE wear rate increased with increasing surface roughness, wear was not severe except with very coarse metal surfaces. The data obtained in these studies formed a comparison basis for the subsequent evaluation of potentially superior materials for prosthetic joints.     

一种新型润滑剂对08Al板拉深成形的影响

通过拉深成形试验,研究了一种新型植物粉-水基润滑剂对08Al冷轧钢板成形行为的影响。结果表明：与无润滑条件相比,该润滑剂显著改善制件表面质量,且使最大拉深力降低约14％。     

304不锈钢中板酸洗缺陷分析

分析了不锈钢中板酸洗后产生缺陷的原因,改进措施为:对连铸坯进行扒皮处理、加强酸洗、轧后快冷。     

新型CZ-4型玻璃润滑剂在斜轧穿孔机穿制不锈钢管的应用

介绍了CZ-4型玻璃润滑剂的性能。采用CZ-4型玻璃润滑剂穿制不锈钢毛管的试验结果表明,这种润滑剂能满足穿制长度大于900mm管坯的工艺要求;能降低铝合金顶头和穿孔导板的消耗。     

不锈钢板料拉深润滑新工艺

不锈钢板料拉深时,在毛坯表面涂覆丙烯酸清漆有效避免了毛坯和模具工作表面直接摩擦,解决了不锈钢拉深粘模、划伤工艺难题,拉深后零件表面光洁。将丙烯酸清漆用于不锈钢、高温合金、钛合金板料拉深成形,都获得了良好的效果。     

不锈钢筒形件深拉深新工艺

传统工艺中,1Cr18Ni9Ti不锈钢板料需多次拉深加工,其生产周期长、产品成本高、生产效率低.通过实验探究,在合理地调整凹、凸模间隙,特别是采用新的润滑剂和润滑方法,同时取消或改变热处理方法的情况下,同样可以深拉深出表面质量理想的不锈钢筒形件.在整个生产工艺中,零件拉深成功的重要因素是合理选择和使用润滑剂,3种润滑剂的配合使用,保证了拉深过程的顺利完成.将该方法用于批量生产,模具寿命大大延长,并取得了很好的生产效益.     

太钢双相不锈钢管坯的试制

介绍了山西太钢不锈钢股份有限公司双相不锈钢管坯的试制工艺、化学成分、组织与性能。试制结果表明,通过控制锻造温度及适当的固溶处理,可以有效解决锻造过程中出现二次奥氏体及金属间化合物的问题。太钢生产的双相不锈钢管坯,其力学性能、抗点蚀性能等与国外同类产品相当,经加工成钢管后,已逐步应用于油气田开采中。     

不锈钢表面含Cu功能梯度复合改性层的制备及抗菌性能

为提高奥氏体不锈钢(ASS)的耐磨性及赋予其抗菌性能,应用改进的活性屏离子渗氮(ASPN)技术,将纯铜冲孔板置于不锈钢冲孔板上面作为活性屏的顶盖,对316奥氏体不锈钢在低温下(430℃)进行表面渗氮处理,在其表面形成由含Cu抗菌沉积层和S相(氮在奥氏体中的过饱和固溶体γ_N)硬质支撑层组成的功能梯度复合改性层。用扫描电镜(SEM)及其所附能谱仪(EDS)、X射线衍射仪(XRD)表征复合改性层的组织形貌、成分及相结构。用显微硬度计和往复摩擦磨损试验机测试了基体和复合改性层的显微硬度和摩擦磨损性能,用金黄色葡萄球菌进行体外抗菌试验评价复合改性层的抗菌性能。结果表明,在偏压达到250 V后,形成了连续分布的硬质S相扩散层和含Cu沉积层组成的复合改性层。改性层表面最高硬度可达928 HV0.05,与Si₃N₄小球对磨时比磨损率较基体降低约57.76%,显著提高了不锈钢的耐磨性。抗菌试验表明,复合改性层与金黄色葡萄球菌接触24 h后,对金黄色葡萄球菌抗菌率提高到98.5%。改进的活性屏离子渗氮技术制备的功能梯度复合改性层可以有效提高...     

A friction model for cold forging of aluminum, steel and stainless steel provided with conversion coating and solid film lubricant

Adopting a simulative tribology test system for cold forging the friction stress for aluminum, steel and stainless steel provided with typical lubricants for cold forging has been determined for varying normal pressure, surface expansion, sliding length and tool/work piece interface temperature. The results show, that friction is strongly influenced by normal pressure and tool/work piece interface temperature, whereas the other process parameters investigated show minor influence on friction. Based on the experimental results a mathematical model has been established for friction as a function of normal pressure and tool/work piece interface temperature. The model is verified by process testing measuring friction at varying reduction in cold forward rod extrusion.     

1Mn18Cr18N钢无磁性护环锻件的试制

1Mn18Cr18N钢系无磁性高锰奥氏体不锈钢,该钢种合金含量高,可锻温度区间窄,在锻造过程中易出现表面裂纹。采用电炉冶炼、电渣重熔工艺获得优质钢锭。锻造加热温度为1190~1210℃,终锻温度在900℃以上。多火次,小压下量锻造,把表面裂纹减轻到最低程度。固溶处理后生产出了满足用户需求的护环锻件。     

The study on lubrication action with water vapor as coolant and lubricant in cutting ANSI 304 stainless steel

Water vapor is a new type of environmental friendly coolant and lubricant. In this study, the friction test was carried out by using the water vapor as lubricant, and the friction pair was made of cement carbide K20 and ANSI 304 stainless steel. In order to study the lubricating action of water vapor as coolant and lubricant in cutting ANSI 304 stainless steel, experiments were carried out with K20 cutter. Through chemical state analyses of elements on tool–chip interface by means of XPS and Gibbs free energy calculation, the chemical reaction process was discussed between water molecule, oxygen atom and fresh tool–chip interface. Experimental results showed that an adsorption film and a tribo-chemical reaction film are formed on the tool–chip surfaces due to its excellent penetration performance and ability to form boundary lubrication layer. The multi-dimensional metal-oxide formed during the reaction weaken the mutual action between tool bulk material and chip. The cutting force and tool flank wear are reduced rapidly, and hence the tool wear is reduced about 50–75% compared with dry machining.     

爆炸焊不锈复合钢板结合面裂纹的判定

通过对X射线底片中可疑影像的分析,结合爆炸焊不锈复合钢板的成型过程,利用金相检验、无损检测、受力分析等方法,确定这一影像为爆炸焊不锈复合钢板结合面产生的裂纹。对可疑部位进行机械清理,发现裂纹形态与分析结果相吻合,为以后处理类似问题提供了判定依据。     

Surface stability and conductivity of a high Cr and Ni austenitic stainless steel plates for PEMFC

In order to use stainless steel as bipolar plate for PEMFC, electrochemical behavior of a high Cr and Ni austenitic stainless steel was studied in the solutions containing different concentration of H2SO4 and 2 mg·L-1 F-, and interfacial contact resistance was measured after corrosion tests. The experimental results show that the passive current density lowers with decreasing the concentration of H2SO4. The interfacial contact resistance between carbon paper and passive film formed in the simulated PEMFC environment is higher than the goal of bipolar plate for PEMFC. Surface conductivity should be further reduced by surface modification.     

爆炸焊不锈复合钢板结合面裂纹的判定

通过对X射线底片中可疑影像的分析，结合爆炸焊不锈复合钢板的成型过程，利用金相检验、无损检测、受力分析等方法，确定这一影像为爆炸焊不锈复合钢板结合面产生的裂纹。对可疑部位进行机械清理．发现裂纹形态与分析结果相吻合，为以后处理类似问题提供了判定依据。