February 2022 Volume 4

MATERIALS

Titanium is a metal that offers high strength-to-weight levels, high temperature resistance, and corrosion resistance. Ti alloys have valuable applications in aerospace, medical, and chemical processing. Its higher cost drives a need to manufacture to near-net shapes and optimize material yields. Forging temperatures for Ti alloys range between 1450- and 1950-degrees Fahrenheit. Lower temps up to 1650 Fahrenheit are used for unalloyed Ti while higher levels are for Ti alloys. Maintaining proper temperature while working Ti is essential as the metal changes its internal structure due to alloy chemistry and hot working temperature applied. Die heating is critical as heat losses through the tooling can produce defective forgings. Forging loads required also are significantly altered by temperature with lower degrees Farenheit drastically increasing metal flow stresses. This requirement for high die temps drives the usage of nickel-based superalloys for tooling because standard tool steels would soften at those levels. Forging strain rates (speed of deformation) for Ti alloys do not influence the forgeability of the metal. Therefore, using hammers or presses is not a major factor. Ti alloys generally require 1.5 to 2 times the forging capacity of steel alloys. A major difference in working with Ti is the need for protecting the stock from contamination by oxygen, nitrogen, hydrogen, and carbon during heating. This is commonly done by coating the billet

stock with a glaze or glass “frit” that is applied before exposure to high temperatures. The coating also acts as a lubricant to metal flow and insulates the stock from die chill cooling that could affect the forging. Additional conventional die lubes may also be applied during the process. These points are merely the basics when forging aluminum and titaniummaterials. Muchmore will be learned as the forger develops a stable and consistent process to produce quality parts.

Richard Polenick is the semi-retired Technical Manager for Ellwood Specialty Steel inNewCastle, PA.He has over twenty- five years of experience in manufacturing including positions with General Motors and Delphi Corp. in materials, design, and tool engineering. In his current position he oversees the application and technical support for the tool steel products that ESS markets to its customers. He holds degrees in Metallurgical Engineering and Manufacturing Management and resides in Warren, OH.

SOUTHWEST STEEL PROCESSING LLC YOUR SINGLE SOURCE FOR HIGH-VOLUME CUSTOM STEEL FORGING SSPFORGE.COM | (870) 523-8791

Delivering quality forged components with fast lead times. Fully automated, high-volume custom forging

Wide variety of advanced CNC machining Offering complete finish machining of your forged components.

Full range of heat treating services

Including quenching, tempering, normalizing, annealing and induction hardening.

CONTACT JUSTIN OWEN | JOWEN@PARK-OHIO.COM

FIA MAGAZINE | FEBRUARY 2022 35