For years companies have used rod frame fabricated baskets for batch loading their production product. This method of processing product has had its share of inherent issues.
Rod Frame Baskets are typically formed and welded from 1⁄2” diameter Type 330 grade material. The round rod is weak from an engineering standpoint and because it is subjected to high temperatures, typically 1,650 – 1,800 degrees F and then oil or polymer quenched, they are subjected to severe thermal shock.
Cycle after cycle imparts thermal shock to the material causing a weakening of the original basket strength. As the thermal shock continues to take its toll, the wire baskets begin to lose shape from distortion, cracking of the material starts, and those cracks propagate further until the baskets no longer stack as designed and ultimately fail requiring replacement.
Additionally, welding of the rod material during fabrication creates grain growth at the heat affected zones (adjacent to each weld). The grain growth allows for faster carbon penetration into the grain boundaries of the rod which ultimately contributes to the cracking and subsequent failure.
Ferralloy’s SureStack line of one-piece investment cast heat treating baskets eliminate these issues, by providing a better horizontal and vertical engineered basket shape, with inherent strength imparted to the basket details that is much stronger than a rolled, round, wrought product.
Additionally, there are no welds in the basket. The basket is cast in one piece, eliminating the heat affected zones and stalling the process of carbon penetration into the alloy’s grain boundaries.
The baskets stack properly and maintain their shape longer ensuring that the baskets outperform a fabricated basket by many cycles.
Using the number of cycles or quenches per basket or quenches as a measure, these investment cast heat treating baskets can have a functional lifespan of up to 90% longer than traditional, fabricated baskets.
Standard furnace basket sizes of 36 x 24 x 3, 4, 6, 8 & 10” H can meet most customers’ requirements and for the 30 x 24” footprint, multiple heights are available from current tooling as well.
Custom sizes can be produced for specific use with different material grades for higher or lower temperature applications available.