May 2021 Volume 3

EQUIPMENT & TECHNOLOGY

The Use of Superalloys to Extend Die Life By Ted Wilcox & Dustin Wilcox

Today's global market continues to shrink as shipping costs and logistics make bringing parts from across the world just as easy as shipping from the next state over.This means U.S. forging producers are now having to compete with forgers that have drastically different operating costs and regulatory oversight. This makes it difficult to compete and forces U.S. forgers to find all possible cost- saving avenues. As the engineering and alloys of forgings become more complex, forgers are forced to find new ways to overcome these obstacles. Steel producers like Ellwood and Finkl have done great things with the steel they produce, but they cannot make a steel that will address all the issues that forging faces. As a die welding company our goal is to help forgers increase their die life through our use of different alloys that are superior to the die block material. Whether it is alloys that are far more wear-resistant than the block material or alloys that are more crack resistant than the block material, all can be welded into a die impression. By combining the use of these alloys we can address multiple forging problems in a single weld repair. We believe that our ability to increase your die life may be your best way to lower your manufacturing cost to be more competitive. If a forger is willing to work with their die welders and be willing to experiment great results can be achieved. Each forging operation can be different, so it may take a couple of attempts to create the right combination of welding alloys and stress relieving. Doubling Die Life An increase in die life affects the entire forging process. The die blocks can be kept in service much longer, lowering the cost of purchasing new blocks and the machining cost to turn them into dies. When an unwelded die gets too thin to run anymore it has to be scrapped and a new die manufactured.The welded die blocks will be kept at full height and with welded impressions that will get the same performance characteristics every time. Die steel producers try to get through hardness in their blocks, but most forgers see a drop in hardness as they sink deeper into the block. This is especially true with forgers running die blocks measured in feet. On a 50,000 lb die, we've seen the impression in a die as low as 25 HRC. With unwelded die blocks the performance of the die steel decreases as the die is repeatedly forged on and machined, with welded impressions the alloys are new with each run. If die life is doubled you have reduced the die sinking time and cost to half of what it was before, not tomention time spent swapping out dies and downtime on the press. Besides the lowered manufacturing cost, it would free up that equipment and personnel to do other

jobs. If a forger needed to increase die shop capabilities it could be accomplished with cost and time savings instead of adding more equipment and personnel. Most forgers recognize the benefits of superalloys to extend die life, but the cost of an entire die block made of Waspaloy, Hastelloy, or Inconel is usually cost-prohibitive. With the use of die welding a normal die block (4340 material 38-42 HRC) can be turned into a die block with super alloy performance and still have the ability to fight both cracking and wear resistance by mixing iron-based alloys in the cracking locations with superalloys for wear resistance in the impression something that the steel manufacturer cannot produce. A 1,500 lb die block may only require 50 lbs of weld to turn it from a normal die to a die with superalloy performance. Robotic System Impacts For over a decade we have used superalloys to increase die life for the open die and rotary forge industry with traditional MIG welding processes. With the implementation of our robotic systems utilizing pulse arc technology, we have been able to introduce more of these superalloys into closed die forging-both press and hammer dies. With this technology we have successfully weldedWaspaloy directly to the die steel material without the intermediate layers ofHastelloy that was required with traditional MIG welding process. All forging venues can see extended die life with the use of superalloys. The use of Inconel alloys on ring rolling axial cones and main rolls have been extremely successful, but we are always trying to find the next way to increase tooling life even further. We are currently running our second test of applying Waspaloy to Axial cones. The first test was successful but we need more test results to be able to recommend this new process to the whole industry. Work-hardening alloys can offer exceptional wear resistance for flashlands and forming radii. With standard die steels, as the die gets hotter and hotter the steel begins to wear away; if the heat buildup is high enough the die steel anneals and softens which increases the speed of wear until it's out of tolerance. With work hardening alloys, as the surface of the metal starts to move (.001" movement) the alloy will harden and then as the top surface is slowly worn away (.001") the metal beneath it then work hardens, this will continue throughout the thickness of the weld deposit. With our robotic pulse arc power sources we can now safely apply cobalt-based alloys at over a 1/4" thick. In the early days it was only applied at .060" thick. This has given some customers the ability to get two re-sinks out of 1 weld repair. The forger will run the die and see the extended die life that Cobalt can offer then

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FIA MAGAZINE | MAY 2021