September_AMP_Digital

FEATURE A D V A N C E D M A T E R I A L S & P R O C E S S E S | S E P T E M B E R 2 0 1 9 5 7 EXAMPLE 2: CARBIDE FORMATION DURING LPC PROCESS Problem . Understanding possible carbide formation in a component pro- cessed using low pressure carburizing (LPC) is crucial to ensure optimal part performance during service. Carbides can result from a poorly designed LPC process, or from geometric features. Sharp corners especially can be detri- mental. Machining can remove areas of unwanted microstructure with ex- cessive carbide formation, but it might also remove the carburized case that imparts the desired mechanical prop- erties to the part. Solution . Modeling the LPC pro- cess can help to understand when geometric features create a strong possibility to form unwanted carbides 9 Fig. 2 — Plots of axial and radial position (left) for the line of nodes shown (right). Plots show the shape of the two sections of the bore for a free oil quench (blue line), original press quench process (gray line), a straight plug quench process designed using DANTE (green line), a tapered plug quench process designed using DANTE (red line), and a contoured and tapered plug quench process designed using DANTE (purple line). (continued on page 10)