1、Materials Transactions, Vol. 47, No. 4 (2006) pp. 954 to 958Special Issue on Platform Science and Technology for Advanced Magnesium Alloys, III 2006 The Japan Institute of MetalsOptimization of Die Material and Its Surface Coating for Press Forming Magnesium AlloyHaruo Okahara1. Miyoshi Ohara1, Yori
2、nobu Takigawa2 and Kenji Higashi21 Research and Development Department, Kasatani Co., Ltd., Osaka 532-0036, Japan-Department of Materials Science, Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531, JapanGram sizes of die material and die surface coatings were examined with
3、the achieving mass-production of magnesium alloys hy advanced continuous press forming. The results showed thal there is an optimum tungsten carbide grain size of 1 to 2um for press-forming AZ31 magnesium alloy in terms of surface roughness fluctuation. It was also shown that the adherence of ihe DL
4、C coating was improved hy implanting C ions into the tungsten carbide surface. 10,000 times square-cup drawings were successfully achieved at 543 K using C-ion implantation and a DLC coated die together with a newly developed heat-resistant lubricant.(Received November 28. 2005; Accepted February 10
5、. 2006; Published April 15. 2006)Keywords: magnesium, press forming, die, tungsten carbide, grain size, diamond-like carbon (DLCI, C-ion implantation材料交易,47卷,4号(2006)第954 - 958页特殊问题平台科技先进镁合金,三世2006年日本研究所的金属优化冲压成型模具材料及其表面涂层的镁合金Haruo Okahara1。 三好Ohara1 Yorinobu Takigawa2 Kenji Higashi21研发部,Kasatani有限公
6、司,有限公司,532 - 0036年大阪,日本-Department材料科学,工程,研究生院大阪府立大学,酒井法子599 - 8531年,日本克大小的模具材料,模具表面涂层检查实现大规模生产的镁合金已有先进的连续冲压成型。结果表明需要有一个最佳的碳化钨晶粒尺寸的1到2嗯press-forming台湾合金表面粗糙度的波动。也表明国内DLC膜的依从性是提高植入为什么C离子进入碳化钨表面。square-cup图纸都成功地实现了在543 K 10000倍使用C-ion植入和DLC涂死连同新开发耐热润滑剂。(11月28日收到。2月10日2005;接受。 2006年,4月15日公布。2006)关键词:镁、
7、冲压成型、模具、碳化钨、粒度、类金刚石碳(DLCI C-ion 植入1. IntroductionMagnesium alloy is expected to be the next-generation lightweight, high-tech material,1 and many studies have been carried out on it in recent years.2,3 The main method of processing magnesium alloy is casting (thixomolding and die casting),4 but it h
8、as serious problems including low yield and low production efficiency. Continuous press-forming, which is an alternative to casting, is very promising because it is an advanced production technology which makes it possible to mass-produce low cost quality products without surface defects. Such produ
9、cts are better than those produced in other countries. However, magnesium is a material which is fundamentally difficult to work, and is unworkable at room temperature.1 71 Therefore, the magnesium alloy AZ31 is pressed between 523 K and 573 K for easier pyramidal slip. Since magnesium is active at
10、high temperatures, surface scorches and flaws are likely to occur during high-speed press-forming.8 10) There are various problems to be solved, including the occurrence of surface flaws due to the adhesion of magnesium to the die,11 the control of the die temperature during press-forming and the la
11、yout of the progressive die.12The authors are developing high-quality high-speed hot- working transfer press processing of magnesium alloy for laptop PC casing, digital camera and various multimedia device casings as part of a 3-years government-funded Rig. 1 TLM cross-sectional images of the C-ion-
12、implanted layer: a) C-ion-implanted layer of which thickness is 60 nm b) Magnified view of the Cion implanted layer, which shows a four-layer structure. 1 a carbon deposition layer 2 an interlace layer 3 a mixed layer 4 an implantation layer c) Magnified view of the implantation layer, which shows a
13、n ordered structure.l,搞笑。1 TLM C-ion-implanted 的横断面图像层:60 nm)C-ion-implanted 层厚度是 b)接穗植入的放大视图层,它显示了一个但是结构。1 碳沉积一层 2 一个交错层 3 4 混合层注入层 c)植入的放大视图层,它显示了一个有序结构。First, the relation between the duration of the C-ion implantation and the adherence of the DLC coating was examined by scratch tests. Figure 5 s
14、hows the results of a F20首先,之间的关系的持续时间 C-ion 植入和依从性的 DLC 膜被划痕测试检查。图 5 显示了 F20 上的结果J:ig. 2 Results of scratch tests on the DLC coating with a critical load Lc(Ft2) = 57N: a) with the C-ion implantation, b) without the C-ion implantation.J:搞笑。2 划痕测试的结果对 DLC 膜的临界负载 Lc(Ft2)= 57 护士:a)C-ion 植入,b)没有 C-ion
15、植入。Fig. 3 XPS depth profile analysis of the DLC coating lor CI s and W4t by sal plate (a) with C-ion injection (b) without C-ion implantation.图 3 XPS 深度剖面分析的 DLC 膜啦 CI 和 W4t 萨尔板(一)没有 C-ion 植入 C-ion 注入(b)。3. Results and Discussion3.1 Optimization of die surface coatingInitially, we examined die surfa
16、ce coatings. We found that DLC coating exhibited the best lubricity and workability.14 However, it was found that the DLC coating adhered poorly to the metal die and came off immediately after the press- forming procedure. Thus, DLC was unsuitable for practical use. Therefore, we turned our attentio
17、n to the research and development of tungsten carbide hybrid dies (a set of tungsten carbide-inserted progressive dies for use only in the deep-drawing process) in which an inclined C structure is formed by DLC coating after a C-ion implantation to improve the adherence of DLC to the die.1516)The ba
18、se WC-Co material using in this section is F20 with a grain size of less than 1 |im. C ions were implanted into the carbide at a pulse voltage of 20kV.1。结果与讨论1.1优化的模具表面涂层最初,我们检查了模具表面涂层。我们发现DLC膜表现出最好的润滑性和可加工性。14然而,它是发现,DLC膜粘附差金属死后立即掉了媒体,形成过程。因此,DLC是不适合实际应用。因此,我们必须重视研究和开发的碳化钨混合模具(一套钨carbide-inserted吃水
19、深的过程中只使用连续模)的倾斜C结构是由DLC膜C-ion植入后改善DLC die.1516)的依从性F20 上基本 WC-Co 材料使用在本节的晶粒尺寸小于 1 | im。C 离子植入了硬质合金的脉冲电压 20 千伏。Figure 1 shows the TLM cross-sectional image of the C-ion-implanted layer. It confirms that the C-ion-implanted layer is comprised of 4 layers: a C-deposition layer, a surface layer, a mixed
20、 layer and an implantation layer.17XPS was used for analyzing the chemical bonding state of implanted C-ions on the tungsten carbide surface after C-ion implantation. The results revealed a peak at 284.48 eV. Therefore, it is assumed that the C ions implanted into the carbide are present as a C-C or
21、 C-H chemical bond.Figure 2 shows the scratch test results on the DLC coating, (a) with C-ion implantation and (b) without C-ion implantation. Where C ions were not implanted, the DLC coating fractured at 50 N or less, whereas C-ion implantation allowed a critical load of 50 N or greater. This resul
22、t indicates that the C-ion implantation improves the adherence of DLC coating.XPS was used for depth profile analysis of the DLC coating for Cls and W4f, (a) with C-ion implantation and (b) without C-ion implantation. The results are shown in Fig. 3. Where C ions were not implanted, the greater the
23、depth, the more rapidly C decreased and W increased, whereas where C ions were implanted, both C and W levels gradually changed with increasing depth. These results suggest that improved adherence is due to reduced stress on the DLC coating resulting from an increase in the C ratio in the carbide su
24、rface.3.1 Optimization of grain size of tungsten carbideFigure 4 shows the SEM images of four kinds of tungsten carbides. The mean grain size of each material is also summarized in Table 3图1显示了TLM C-ion-implanted的横断面图像层。 它证实C-ion-implanted层由4层:C-deposition层,表层、混合层和一个植入layer.17”XPS用于分析化学成键的植入C-ions C
25、-ion植入后碳化钨表面。结果显示峰值为284.48 eV。因此,假设C离子植入硬质合金存在中心距或从化学键。图2显示了DLC膜上的划痕试验结果,与C-ion植入(a)和(b)没有C-ion implanta。其中C离子植入,DLC膜破裂或少于50 N,而C-ion植入允许50 N或更高的临界载荷。这一结果表明,C-ion植入改善DLC膜的依从性。XPS是用于深度剖面分析的DLC膜Cls和W4f C-ion植入(a)和(b)没有C-ion植入。结果如图3所示。在C离子植入,深度越大,越快C和W的增加而减少,而C离子植入,C和W两个层面逐渐随着深度增加而改变。这些结果表明改善依从性是由于减少压力
26、的增加所带来的DLC膜中的C比硬质合金表面。1.1优化粒度的碳化钨图 4 显示了四种钨的碳化物 SEM 图像。每个材料的平均粒径也总结在表 3Fig. 4 SEM images oi iour kinds oi tungsten carbides: a) F20 with mean gram size of less than 1.0 pm, b) D50 with mean grain size of 1.0-2.0 pm, c) G70 with mean grain size of 2.0 VO pm. d) C70 with mean gram size of 3.0-5.0 Jim.
27、图4 SEM图像oi我our oi碳化物:钨)F20上意味着克的大小小于1.0点,b)D50的平均粒径1.0 - -2.0点,与平均粒径为2.0 c)G70 VO点。与平均3.0克的大小3.0 d)C70吉姆。ig. 5 Effects of the ion implantation time on the adherence of the DLC coatingtungsten carbide with a fine grain size less than 1 jam and a C70 tungsten carbide with a coarse grain size of about
28、4|im. It became clear that the adherence of the DLC coating improved with an increase in the C-ion implantation time irrespective of the grain size of the tungsten carbide.Second, an XPS depth profile analysis was conducted for Cl s. Ols, Co2p3/2 and W4f. The results shown in I igs. 6 and 7 confirme
29、d th.it the implanted C ions reached about the same depth in all tungsten carbide samples irrespective of the grain size, that is, tungsten carbide grain size had nothing to do with the C-ion implantation depth.The frictional coefficient was measured on C-ion implanted and DLC coated F20 carbide. It
30、 was found that the DLC coating significantly lowered the frictional coefficient, making it possible to keep the frictional coefficient under 0.1搞笑。5的影响离子注入时间在DLC膜的依从性碳化钨与细粒度小于1果酱和C70碳化钨粗粒度约4 | im。很明显,DLC膜的依从性改善与提高C-ion植入时间不管硬质合金的晶粒尺寸。第二,XPS深度剖面分析进行了Cl年代,Ols Co2p3/2 W4f。结果我igs所示。6和7 th确认。植入C离子达到相同的深
31、度在碳化钨样品粒径无关,也就是说,碳化钨颗粒和C-ion植入深度无关。摩擦系数是衡量 C-ion 植入和 DLC F20 上涂层硬质合金。发现了 DLC 膜显著降低了摩擦系数,从而能够保持摩擦系数低于 0.1Details of the wear properties of DLC coating have been reported in another paper.13Next, we examined the effect of the grain size die materials on the surface roughness of the press formed articl
32、es. We produced dies using WC-Co with various grain sizes. The shape of the dies was a deep-drawing square-cup with the radii of the two types of corners of 4 mm and 2.3 mm. For each die, 10,000 times square-cup drawings were carried out at 543 K, the degree of damage on the die surface was visually
33、 inspected, and the surface flaws of the press formed articles were measured with a surface roughness meter to determine the optimal grain size for tungsten carbides. The measured points for surface roughness are shown in Fig 8. A newly developed heat-resistant lubricant was used for the drawing. Th
34、e amount of lubricant used was 3,000 mg/m2. Details of the lubricant have been reported in another paper.18DLC膜的耐磨性的细节在另一个paper.13已报告接下来,我们研究了晶粒尺寸的影响模具材料表面粗糙度的形成的新闻文章。我们生产模具使用 WC-Co 不同晶粒大小。模具的形状是一个深拉 square-cup 半径的两种类型的角落 4 毫米和 2.3 毫米。对于每一个死,10000 次 square-cup 图纸进行了在 543 K,模具表面的损害程度是视觉检查,文章和新闻表面缺陷的形
35、成与表面粗糙度测量仪来确定最优粒径对钨的碳化物。表面粗糙度的测量分图 8 所示。一个新开发的耐高温润滑剂用于绘画。润滑剂的用量是 3000 mg / m2。润滑剂在另一个 paper.18 已报告的细节Fig. 8 Measured points for surface roughness on deep-drawing square cups: a) Viewed from the above b) Viewed from the side.图 8 点测量表面粗糙度在深拉广场杯:1)从以上 b)从侧面观察。For F20 tungsten carbide, the pressing test
36、 was interrupted because of the conspicuous wear and tear of the DLC coating after 5,000 times drawings. In the pressing test conducted using tungsten carbide dies with other grain sizes, 10,000 times drawings were achieved in every case. Of the tested materials, D50 had the most stable stamping per
37、formance; Figs. 9, 10 and 11 show the results. Determination of the approximate formula confirmed that D50 was the most stable material in terms of surface roughness fluctuation.From these results, the optimum grain size of tungsten carbide was not less than 1 m but in the range of 1 to 2 jam. It ha
38、s been reported that oil film retention is improved by the micro-pool mechanism which brings the oil films closer to the state of fluid lubrication, thereby improving material processability when the die surfaces are rougher.19-21 Detailed analysis of this phenomenon will be conducted in further res
39、earch.F20上为碳化钨,按测试被打断,因为明显的磨损后的DLC膜图纸5000倍。在紧迫的测试进行了使用碳化钨死亡与其他颗粒大小,在每种情况下取得了良好的图纸10000倍。测试材料,D50最稳定的冲压性能;无花果。9、10和11显示了结果。测定确诊的近似公式,D50最稳定的材料表面粗糙度的波动。从这些结果,碳化钨的最佳粒度不少于1 m但在1到2的范围果酱。据报道,油膜保留由micro-pool改进机制,使石油电影更接近流体润滑的状态,从而提高材料的加工性能,当模具表面是粗糙的。19日至21日的详细分析这一现象将开展进一步的研究。4. ConclusionsThe results showe
40、d that there is an optimum tungstencarbide grain size of 1 to 2 |im for press-forming AZ31 magnesium alloy in terms of surface roughness fluctuation. In addition, it was shown that the adherence of the DLC coating, which was likely to exfoliate using the conventional technique, could be improved by
41、implanting C ions into the carbide surface. 10,000 times square-cup drawings were successfully achieved at 543 K using C-ion implantation and a DLC coated die with a newly developed heat-resistant lubricant.Now that the optimal progressive die layout has been determined, a 100,000 times continuous p
42、ress-forming test with a target Ra value of 1.5 m or less is in progress.1。结论结果表明,存在一个最佳碳化钨晶粒尺寸的1到2 | im press-forming台湾合金表面粗糙度的波动。此外,它表明,DLC膜的依从性,这可能是去角质使用传统的技术,可以改善在硬质合金表面植入C离子。square-cup图纸都成功地实现了在543 K 10000倍使用C-ion植入和DLC涂死与新开发耐热润滑剂。现在,最优级进模布局已经确定,100000 次连续 press-forming 测试目标 Ra 值 1.5 米或更少的进步。Ac
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