Effect of Profile Corners on the Nitriding Treatment of AISI H13 Hot Extrusion Dies

Abstract

One of the utmost challenges of hot aluminum extrusion is to design the die cavities with sharp corners (used to extrude thin-walled profiles) by considering the effective nitriding suiface treatment of the die hearing surface in terms of nitride layer uniformity. In the present study, various AISI HJ3 steel samples (having commonly used profile geometric features) are manufactured using wire electro-discharge machining (EDM) and subsequently nitrided using two-stage controlled nitriding treatment. As a special case, corner features are investigated in terms of compound and nitride layers formation using optical and scanning electron microscopes. Finite element (FE) code ABAQUS is used to simulate the nitriding process using mass diffusion analysis in line with experimental set up. Both experimental and numerical results are found in close agreement in terms of nitrogen concentration and corresponding microhardness profiles. Some design modifications are implemented in FE code for corner profile features for uniform nitride layer development.In view of the current results, some design guidelines are suggested for effective and uniform nitride layer formation in order to secure high quality extruded product and extended die life.

Change in Microstructure and Hardness of Additively Manufactured Aisi H13 Steel by Heat Treatment and Nitriding Processes

“…HIP before quenching and tempering (Q&T) for hot-work tool steel manufactured by laser powder bed fusion significantly increased the impact toughness and ductility and slightly increased the yield and ultimate tensile strength values compared with the Q&T condition [16]. Besides, nitriding technology could help improve the surface hardness of steel [16][17][18]. However, the change of phases and hardness of additively manufactured H13 steel during heat and surface treatment processes including high-temperature annealing, quenching, tempering, and nitriding has not been demonstrated in the literature.…”

Optimization Design of I-Type Plastic Extrusion Die Based on Flow Balance

“…Therefore, it is extremely essential to study the plastic extrusion die, especially the design of its transition section and forming section. The extrusion forming process of plastic profiles is a complex continuous nonlinear dynamic process involved thermodynamics, fluid mechanics, organic chemistry, mechanics and other disciplines, making the extrusion die design more difficult than other forming mold design [1][2][3][4][5][6].…”