D. E. Wert, P. Novotny, Carpenter Technology Corporation, Reading, PA
Carpenter Custom 465 Stainless alloy, a high strength PH stainless steel designed to provide the highest combination of strength and toughness commercially available, is seeing increasing acceptance in the Aerospace industry. Because of its combination of high strength and corrosion resistance, it is currently specified for use by, or is under consideration by, a number of major Aerospace providers. Current uses for the alloy include a higher strength replacement for 15-5 PH parts, and a drop-in corrosion resistant replacement for 4330M or 4340M parts. In addition, major Aerospace manufacturers have designed new systems around the use of Custom 465, realizing the benefits this alloy provides over other currently available materials. For Aerospace uses to date, the alloy has been provided in either solution treated bar, or overaged billet form. Parts made from base have been directly machined and aged, and parts made from billet have been forged, followed by the solution anneal/refrigerate/age process. Ongoing alloy/process development work at Carpenter Technology Corporation has resulted in a new material condition which is now available to the Aerospace community. This material condition is solution treated and cold worked bar. This paper will outline the properties obtainable by cold working Custom 465 Stainless bar up to 70% prior to aging. This process results in significantly increased strength, while still allowing the material to meet the tensile ductility requirements of AMS 5936B. In addition, CVN impact toughness is shown to increase at the increased strength level resulting from cold working. Finally, along with the other benefits, the stress corrosion cracking resistance as measured by slow strain rate tensile testing is also improved at a given strength level in cold work/aged material compared to direct aged material.
Summary: Carpenter Custom 465 Stainless alloy, a high strength PH stainless steel designed to provide the highest combination of strength and toughness commercially available, is seeing increasing acceptance in the Aerospace industry. Because of its combination of high strength and corrosion resistance, it is currently specified for use by, or is under consideration by, a number of major Aerospace providers. Current uses for the alloy include a higher strength replacement for 15-5 PH parts, and a drop-in corrosion resistant replacement for 4330M or 4340M parts. In addition, major Aerospace manufacturers have designed new systems around the use of Custom 465, realizing the benefits this alloy provides over other currently available materials. For Aerospace uses to date, the alloy has been provided in either solution treated bar, or overaged billet form. Parts made from base have been directly machined and aged, and parts made from billet have been forged, followed by the solution anneal/refrigerate/age process. Ongoing alloy/process development work at Carpenter Technology Corporation has resulted in a new material condition which is now available to the Aerospace community. This material condition is solution treated and cold worked bar. This paper will outline the properties obtainable by cold working Custom 465 Stainless bar up to 70% prior to aging. This process results in significantly increased strength, while still allowing the material to meet the tensile ductility requirements of AMS 5936B. In addition, CVN impact toughness is shown to increase at the increased strength level resulting from cold working. Finally, along with the other benefits, the stress corrosion cracking resistance as measured by slow strain rate tensile testing is also improved at a given strength level in cold work/aged material compared to direct aged material.
