20th International Forgemasters Meeting - IFM 2017

Abstract Patriot Forge is a producer of 17-4 PH stainless steel components for the gas turbine and gas compression industry. To meet the demand of this high strength precipitation hardening steel in large forgings, Patriot has commissioned a new 5000 ton press. This alloy is open die forged from air melted, bottom poured ingots of different sizes. For the mentioned above application non-destructive testing is indispensable to guarantee high quality and expected performance in the field. The use of larger ingots has resulted in increased segregation. This paper studies elemental segregation being detected during magnetic particle inspection. There will be a discussion about the relevance or non-relevance of these indications. Highly segregated areas can give false indications based on magnetic response of different phases present in the steel. SEM microscopy and X ray diffraction were used to carry on this investigation. Also magnetic particle inspection was performed under a microscope to analyse the magnetic particle behaviour around different phases present in 17-4 precipitation hardening stainless steel. Comparative data regarding mechanical properties of areas with non-relevant indications versus other areas within the forging will be presented.