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Metalforming	:: Forming/Bending :: Stamping/Piercing :: Powder Compacting :: Roll Forming

:: Wear and Toughness Chart :: Compressive Yield Strength vs HRC ::CPM 1V & 3V Upgrades POWDER COMPACTING Compaction tooling components need to have various combinations of high hardness, toughness, and wear resistance. High hardness helps to resists deformation or mushrooming under high compaction pressures. Toughness is necessary to resist chipping and cracking which may be caused by dynamic or uneven loading, fragile part geometries, and thin or unsupported die sections. Wear resistance allows the tools to withstand the abrasion caused by powder flow during compaction and also encountered during part ejection. Because of the different operating requirements for each component, material recommendations differ slightly for each. Upper and lower punches transmit the pressure of compaction, may face uneven or dynamic loading, and see abrasion from powder flow. Thus, these components usually call for steels with good combinations of high hardness, wear resistance, and good toughness. Typical steels may include A2, CruWear, CPM 3V, M4, and 10V. Dies and die inserts are primarily subject to abrasion. Because they are often well supported by a case or holder, toughness may not be as critical as for punches, and thus lower toughness tool steels may be suitable. Consider tool steels with high wear resistance. Common grades could include D2, CruWear, M2, CPM 10V, 15V, T15, or Rex 121. Carbide dies may also be suitable, when toughness needs are particularly low. Of course, when difficult geometries or thin projections require more toughness considerations, some of the higher toughness punch grades listed above may also be appropriate. Core rods and inserts are typically long, thin parts which may face dynamic and uneven loading, and wear from powder flow and part ejection. As "place-holders" for openings in the part, they may not undergo severe compression during compaction, and thus high hardness may not be as critical as it is for punches. Consider tool steels with high wear resistance and good toughness, such as A2, CruWear, or CPM 3V, 9V, or M4. Regardless of which component is of concern, some common property guidelines will help when trying to pick a tool steel to upgrade tool performance or solve problems. To minimize deformation, consider tool steels with high hardness and therefore high compressive yield strength. High hardness is usually the first consideration for bending and forming tooling. However, hardness is not a highly distinguishing factor as most of the tool steels have similar working hardness ranges. If A2 or D2 tools are experiencing deformation, other grades with higher hardness, such as CPM M4, may be beneficial. The Working Hardness Range table and Hardness vs. Compressive Yield Strength chart can help select an appropriate grade for improving the deformation resistance of tools. A broken die is worthless, often beyond repair. To minimize breakage or chipping, consider tool steels with high toughness. Where A2 or D2 are prone to breaking or chipping, tool steels such as S7 can offer high toughness, but often at a considerable drop in wear life. Many of the CPM grades offer high toughness, without sacrificing wear life. CPM 3V may be substituted for D2, to offer a substantial increase in toughness, while retaining long wear life. See the Wear Resistance and Toughness chart for more details. Abrasion of the tool involves actual metal loss on the tool and results in loss of tolerances in the workpiece. To minimize abrasion consider tool steels with high wear resistance. If A2 or D2 are showing premature wear,without deformation problems, higher alloy, higher wear resistance tool steels are in order. Try CruWear, or CPM 10V, M4, or 3V. See the Wear Resistance and Toughness chart for more details. Coatings may also aid wear problems. If coatings are used, tool steels with suitable heat treat processes should be used as substrates. Generally, steels tempering at 1000F (540C) or higher are best suited as substrates for PVD processing, as lower tempering steels such as D2 may soften during exposure to the PVD processing temperature. CruWear, M2, CPM M4 or 3V offer such heat treat response. See individual grade datasheets for heat treat recommendations.