Rolling contact fatigue behaviour of Pyrowear 675

Abstract

This work represents one phase of a comprehensive gear and bearing materials programme, involving both substrates and coatings. The programme is directed at enhancing both the performance and durability of gears and bearings for insertion into military systems. This paper deals specifically with the Pyrowear 675 alloy, a carburising stainless steel recently developed by Carpenter Technology Corp. The rolling contact fatigue (RCF) performance of steel specimens with four different heat treatments is presented. The optimum heat treatment produced a fivefold increase in both B10 and B50 lifetimes compared with M50 steel, the standard turbine engine bearing steel. Thus, the improved RCF performance combined with good corrosion resistance make Pyrowear 675 alloy an attractive candidate for advanced bearing applications.

Failure Analysis of Horizontal Hinge Pin Components from an Army Cargo Helicopter

“…• If the level of the service load spectrum cannot be reduced, consider utilizing material alternatives that may provide a greater service life than the M50 steel used in the current roller and ring designs. Literature indicates that M50NiL (a carburizing tool steel) and Pyrowear 675 (a carburizing stainless steel) may provide an increase in rolling contact fatigue life [7,8]. • If early detection of HHP assembly failures is required to mitigate air worthiness risks, the feasibility of a nondestructive vibration analysis method should be examined.…”

Interaction of anti‐wear additiveTCPwith advanced bearing steels

“…Some of the key bearing performance attributes needed to meet these emerging engine needs include materials with good core fracture toughness for high‐speed/high‐load operation, excellent hot‐hardness for surface wear and fatigue resistance, and good corrosion resistance for operation in hostile environmental conditions among other desirable properties. Towards this end, a number of advanced steels have been developed and extensively characterised with the potential of meeting these requirements including Pyrowear 675 (P675), Cronidur 30, CSS‐42L and nitrided M50NiL 1–8 . The high hardness and strength of these materials is mostly attributed to a combination of grain size and alloying elements such as Cr, W, Mo, V and Co, all of which are known to form carbides during the heat treatment (carburisation) process.…”

“…Towards this end, a number of advanced steels have been developed and extensively characterised with the potential of meeting these requirements including Pyrowear 675 (P675), Cronidur 30, CSS-42L and nitrided M50NiL. [1][2][3][4][5][6][7][8] The high hardness and strength of these materials is mostly attributed to a combination of grain size and alloying elements such as Cr, W, Mo, V and Co, all of which are known to form carbides during the heat treatment (carburisation) process. These alloys could also be modified using combined or secondary heat treatment (duplex hardening) such as carbo-nitriding and nitriding to improve corrosion and wear resistance.…”