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- Liljengren, Magnus, et al.
(författare)
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Die materials, hardening methods and surface coatings for forming of high, extra high and ultra high strength steel sheets (HSS/EHSS/UHSS)
- 2006
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Ingår i: Drawing the Things to Come: Trends and Advances in Sheet Metal Forming. - : Inst. de Engenharia Mecânica e Gestão Industrial. - 9789728953065 ; , s. 597-604
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- During the past years, large efforts have been made at Volvo Cars to establish a scientific and systematic approach to selection of die materials, hardening methods and surface treatments/coatings. These efforts were initiated, since both new higher strength sheet materials and new die materials with better performance were introduced. Both these higher strength sheet materials and higher performance die materials needed to be industrialized. Volvo cars transferred to a so-called Dry Presshop several years ago. This means that only the rust protection oil applied by the material supplier to the sheet prior to delivery is allowed as the stamping lubricant. No additional lubricant can be accepted. This transfer is done with regard to environmental improvement and a lean production philosophy. "Trouble-shooting" (reduction of abrasive and adhesive die wear) by using additional lubrication is therefore not possible anymore.In this investigation 1.20 and 1.95 mm thick uncoated and hot-dip galvanized sheets of DP600, DP800 and DP1000 were tested. The wear behaviour of the die materials Sverker 21 (D2), Calmax, Sleipner, Weartec, Vanadis 6 and Vancron 40 were studied. Uncoated, plasma-nitrided, PVD-coated (CrN and TiAlN) versions of dies made in the above-mentioned materials were tested.The tests were carried out both in laboratory in a U-bend test equipment and in real stamping production. Based on the results obtained in laboratory and production tests, guidelines were established for selection of die materials and surface treatments in stamping of DP600, DP800 and DP1000. These guidelines are described in the present paper.
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| 2. |
- Ullman, Andreas, et al.
(författare)
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On laser hardening of trimming tools & dies
- 2006
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Ingår i: Drawing the Things to Come: Trends and Advances in Sheet Metal Forming. - : Inst. de Engenharia Mecânica e Gestão Industrial. - 9789728953065 ; , s. 613-620
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this study, the methods used to harden trim dies were at the focus. Laser surface-hardening was compared to induction- and through-hardening for small and medium-size series production. The sheet materials used were 1.2 mm thick uncoated Docol 600DP (DP600) and 1.95 mm thick uncoated Docol 600DL (DP600). The die materials tested were Fermo, Carmo and Sleipner.This investigation showed that the optimum laser-hardening parameters must be established for each trim die material. The trim die in laser-hardened Sleipner exhibits the smallest wear. The dimensional changes after laser hardening are very small. The burr height is very small, regardless of how the trim die is hardened. In this study, two sets of production trim dies were manufactured and set up. This production trim dies are used in the manufacture of V70 B-pillar Left and Right. Laser hardening resulted in a lead time reduction by 5 labour days. However, the Tool & Die unit at Volvo Cars estimates that the lead time reduction obtained with laser hardening should be around 10 days under normal conditions. The cost analysis conducted by the Tool & Die unit at Volvo Cars shows that the manufacturing costs are reduced by 6%, if laser-hardening is selected. These production trim dies are and will be monitored continuously. As this paper is being written, these dies have been subject to 270,000 strokes without exhibiting any problems.
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