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Copyright © 1996-2008 Badger Metal Tech, Inc – Rev 05-2008 Catastrophic Failure of Die Material Steel whose acceptance criteria falls out of the 207- 2006.

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Presentation on theme: "Copyright © 1996-2008 Badger Metal Tech, Inc – Rev 05-2008 Catastrophic Failure of Die Material Steel whose acceptance criteria falls out of the 207- 2006."— Presentation transcript:

1 Copyright © Badger Metal Tech, Inc – Rev Catastrophic Failure of Die Material Steel whose acceptance criteria falls out of the NADCA recommendation (was prior to first quarter 2006)was prior to first quarter 2006 Charpy impact fracture toughness levels are below recommended specs of NADCA , Chrysler or GM spec. (above 10 ft lbs.) Incorrect annealed microstructure and excessive banding. Improper or poorly performed heat treatment procedures. Happens far too often. Gross Cracking

2 Copyright © Badger Metal Tech, Inc – Rev Steel Acceptance Criteria and Heat Treatment Crucial to Tool Life ( live link ) Steel Acceptance Criteria and Heat Treatment Crucial to Tool Life ( live link ) Recommended reading: NADCA publication ##229 (2006) Steel & Heat Treatment Acceptance Criteria Recommended reading: NADCA publication ##229 (2006) Steel & Heat Treatment Acceptance Criteria Cost $80 through NADCA Cost $80 through NADCA Click this link: NADCA Publication Click this link: NADCA Publication NADCA Publication NADCA Publication

3 Copyright © Badger Metal Tech, Inc – Rev Ideal Steel Attributes Resistance to thermal fatigue cracking – low coefficient of thermal expansion, high thermal conductivity, high hot yield strength, temper softening resistance, high creep strength, and adequate ductility Resistance to thermal fatigue cracking – low coefficient of thermal expansion, high thermal conductivity, high hot yield strength, temper softening resistance, high creep strength, and adequate ductility Resistance to gross cracking – high fracture toughness, high yield strength, and proper heat treatment Resistance to gross cracking – high fracture toughness, high yield strength, and proper heat treatment Resistance to soldering - high thermal hardness, high resistance to thermal softening, low solubility in molten aluminum, and good oxidation resistance Resistance to soldering - high thermal hardness, high resistance to thermal softening, low solubility in molten aluminum, and good oxidation resistance Resistance to thermal fatigue cracking – low coefficient of thermal expansion, high thermal conductivity, high hot yield strength, temper softening resistance, high creep strength, and adequate ductility Resistance to thermal fatigue cracking – low coefficient of thermal expansion, high thermal conductivity, high hot yield strength, temper softening resistance, high creep strength, and adequate ductility Resistance to gross cracking – high fracture toughness, high yield strength, and proper heat treatment Resistance to gross cracking – high fracture toughness, high yield strength, and proper heat treatment Resistance to soldering - high thermal hardness, high resistance to thermal softening, low solubility in molten aluminum, and good oxidation resistance Resistance to soldering - high thermal hardness, high resistance to thermal softening, low solubility in molten aluminum, and good oxidation resistance Breakout and pitting are influenced by improvements in die filling conditions. Lubrication and intrinsic barriers are necessary to prevent soldering due to aluminum and iron interaction.

4 Copyright © Badger Metal Tech, Inc – Rev Combination of thermal and mechanical Cracks frequently occur at low temperature or in die steels with low fracture toughness. Usually initiate from deep thermal cracks near cooling lines. Can be avoided by good die design, right material, proper heat treatment, proper SPC. Preheating to min 335 degrees F raises fracture toughness to almost twice as high as that at room temperature. Gross Cracking

5 Copyright © Badger Metal Tech, Inc – Rev High Rockwell hardness* Prone to gross cracking (lowers toughness) Low Rockwell hardness Prone to heat checking High Rockwell hardness* Prone to gross cracking (lowers toughness) Low Rockwell hardness Prone to heat checking Rule of thumb hardness Relationship to Fatigue Failure 46-47Rc A higher hardness of 48-51Rc common for smaller dies vacuum quenched at a high cooling rate. A Lower hardness of 44-46Rc preferred for larger dies. Breakout and pitting are influenced by improvements in die filling conditions. Lubrication and intrinsic barriers are necessary to prevent soldering due to aluminum and iron interaction.

6 Copyright © Badger Metal Tech, Inc – Rev For large tooling that have difficulty achieving high cooling rates, consider the newer steels with better toughness. These steels allow a higher hardness of 49-50Rc with the same cooling rate of H-13 without the risk of gross cracking For large tooling that have difficulty achieving high cooling rates, consider the newer steels with better toughness. These steels allow a higher hardness of 49-50Rc with the same cooling rate of H-13 without the risk of gross cracking Exceptions to the rule of thumb with newer die steels

7 Copyright © Badger Metal Tech, Inc – Rev Table – Steel Compositions (NADCA DMC Report 2006) Die Steels C wt.% Si wt. % Mn wt. % Cr wt. % V wt. % Mo wt % S wt. % P wt. % Heat Checking Resistance Gross Cracking Resistance P.G. H H <0.005<0.02 Dievar KDA TQ QRO RPU

8 Copyright © Badger Metal Tech, Inc – Rev Table – Property Compositions (NADCA DMC Report 2006) Die SteelWashoutIndentationTemper Resistance Hot Yield Strength DuctilityToughnessHardenability P.G. H13 H11 Dievar KDA-1 TQ1 QRO90 RPU

9 Copyright © Badger Metal Tech, Inc – Rev Recommended reading: NADCA publication #531 (May 2007) Users Guide for Relieving Stresses in Die Casting Dies Recommended reading: NADCA publication #531 (May 2007) Users Guide for Relieving Stresses in Die Casting Dies Cost $60 through NADCA – Pages Cost $60 through NADCA – Pages Click this link: NADCA Publication Click this link: NADCA PublicationNADCA PublicationNADCA Publication to relieve surface stresses in Die Casting Dies to relieve surface stresses in Die Casting Dies Other recommended reading


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