Simple Solutions That Work! Issue 12

Continued on next page 59 BACK TO BASICS TOM SCHADE Technical Sales INTERNATIONAL MOLD STEEL, INC. ARTICLE TAKEAWAYS: • How to reduce die surface temperature to reduce porosity, shrinkage and scrap • How thermal conductivity affects heat Using High Thermal Conductivity Steel to Reduce Cycle time, Reduce Scrap, and Improve Part Quality There are many benefits to increasing the cooling rate for an aluminum part in a die cast die. Reducing cycle time is an important cost savings. Improved part quality due to better cast structure of the aluminum, as well as reduced porosity is another. However, there is a limit to how many waterlines, and how close these water lines can be to the molding surface, before gross cracking of the die causes premature die failure in an H13 die. Tungsten alloy components have high thermal conductivity, but their high cost and low mechanical strength limit their practical applications. Recently, two newly developed high thermal conductivity steels, Toolox44, SSAB Sweden, and DHA Thermo, Daido Steel, Japan have been solving more and more problems for die casters By modifying chemistries, in particular lowering Silicon and Chrome, these two producers have come up with high GET THE HEAT OUT Figure 2 thermal conductivity steels with sufficient mechanical properties to withstand the rigors of a die casting environment. One of the first applications first time users (not yet believers) gravitate to, are shot blocks or sprue bushings. Exploding biscuits are no fun, therefore, decreasing their solidification time can eliminate blow-outs and reduce cycle time. As shown in Figure 1 , with both Figure 3