【導(dǎo)讀】沖壓加工作為一個行業(yè)，在國民經(jīng)濟(jì)的加工工業(yè)中占也重要的地位。斷進(jìn)步和沖壓生產(chǎn)的迅速發(fā)展，對沖壓設(shè)計工作提出了愈來愈高的要求。沖壓設(shè)計既是沖壓生產(chǎn)準(zhǔn)備工作的基礎(chǔ)，也是組織正式生產(chǎn)的依據(jù)。藝計算，制定出合理的工藝方案，最后編寫出沖壓工藝卡。應(yīng)的模具總體結(jié)構(gòu)，然后繪制模具總裝圖和零件圖。

　　

【正文】 ]. In this test, the same contact surface is scanned repeatedly in every cycle。 however, in a real stamping operation a die/punch is in contact with fresh, untouched blank surfaces. On the other hand, other wear tests such as (a) strip pulling [9,10], (b) ubending/deep drawing [11–13], (c) strip drawing [12,14,15], (e) draw bead [16], (f) bined drawbead and strip pulling [17], and (g) bending under tension or radial strip drawing [12,18] are more representative of the actual stamping conditions。 however, they are lengthy (. ～15–70 km strip length is needed in bined drawbead and strip pulling test), costly and require special arrangements such as specially slit coils, large test area and extra equipment like hydraulic clamps, presses, coilers/decoilers, etc. With an increasing need to introduce new lightweight materials into the auto body and structures, newer and alternative die materials, coatings, surface treatment/enhancements, and lubricants bee necessary to ensure prolonged die life, petitive part cost and consistent high part quality. Accurate and rapid testing of all possible binations of die material, coating and surface treatment using the existing wear testing methods is not feasible in terms of time, cost and reliability. The main motivation in this study was to establish a test system that provides reliable results, in a rapid manner and also to simulate/control the parameters as much as possible to real conditions. The test system we proposed eliminates the repeated contact surface issues by continuous sweeping of fresh/untouched blank surface by means of tool/die sample. This paper, in essence, presents the results of a study for which the aim was to investigate the effect of different coatings applied on recently introduced airhardening coldwork tool steel, containing 1% carbon, 8% chromium, 2% molybdenum and remainder of iron, on die wear resistance under stamping conditions of DP 600 AHSS grade sheet blanks. The second section of this paper introduces the test system, experimental conditions, die material and sheet blank properties in a detail. Experimental measurements and results are discussed in the third section. The paper is concluded with conclusions and remended future work. 2. Test system An alternative die wear test system was developed with the premise of rapid and accurate wear performance assessment of alternative die materials for newer stamping materials. Its earlier design and parison with existing die wear test methods were discussed in other published work of the authors [19], a brief description of the updated test system is as follows: This die wear test system is based on the use of precise and controlled motion of a vertical machining center (HAAS VF3 CNC)s x, y and zaxes and spindle (no rotation).A load sensor was mounted on the spindle through a holder which also houses the die sample of interest. AHSS sheet blanks are laid on the x–y table with clamps at four corners as can be seen in Fig. 1. CNC was programmed for the precise pressing of die sample and oneway scratching/sweeping on the AHSS sheet blank. Normal force occurring at the die and blank 杜雷：電機(jī)轉(zhuǎn)子零件的沖壓工藝及模具設(shè)計 20 interface was recorded during the tests. Fig. 2 shows the die sample dimension and an actual picture with the wear tracks on the sheet blank. . Experimental procedure and test materials Each die sample was tested along two (2) km track distance under an average normal load of 200N with a sliding speed of purposes, 3 replications were performed with the Sample (I) given in Table 3. DP 600 (DualPhase, 600MPa ultimate tensile strength) sheet blanks of 330mm330mm1mm were used in tests. Chemical position, average surface roughness, and hardness values for the die samples and sheet blanks are tabulated in Tables 1–4. Table 1 Chemical position of airhardening steel substrate material. Substrate Material C Si Mn Cr Mo V An airhardening coldwork tool steel % % % % 2% % Table 2 Typical chemical position of DP600 steel sheet blanks [20]. Material Grade Chemical position 安徽工程科技學(xué)院畢業(yè)設(shè)計（論文） 21 C Mn Si Al S P DP 600 Table 3 Die samples tested, hardness values and average surface roughness values (Ra). Table 4 Hardness and average surface roughness (Ra) values for DP 600 sheet blank Hardness measured (HV1) Average surface roughness, Ra (_m) 203 Specimens provided by DAIDO Steel Co. Ltd were prepared with the following procedure: Firstly all the samples are roughly machined before preheat treatment. In the heat treatment die samples were exposed to gas quenching at 1030 ?C, then tempered for 1h at 550?C. After the heat treatment applied。 the die samples are machined to final dimensions and polished prior to coating process (Thermal Diffusion: TD, Physical Vapour Deposition: PVD, and Chemical Vapour Deposition: CVD). In particular, the second sample is radically nitrided before its PVD coating. In radical nitriding process, different from conventional nitriding, the coating process is done underNH3 andH2 environment and it eliminates the formation of ―white layer‖ which is brittle and needs to be cleaned prior to PVD coating process. The bination of radical nitriding and PVD coating provides increased hardness and peel off resistance for coatings. TD and CVD coated samples are heat treated after coating process again. The final procedure for the sample preparation is polishing of coated samples. Coating thicknesses for all the samples tested are in the range of 5–10_m as reported by provider. Substrate (die sample) + coating configuration Substrate hardness (HRC) Average surface roughness, Ra, before test (_m) I) Substrate + TD coating II) Substrate + radical nitriding TiCN (PVD) III) Substrate + TiCN (PVD) IV) Substrate +mul