EFFECT OF NIOBIUM ADDITION ON STAMPING TOOL STEEL. PROPERTIES . | ||||
ERJ. Engineering Research Journal | ||||
Article 5, Volume 32, Issue 1, January 2009, Page 49-59 PDF (717.93 K) | ||||
Document Type: Original Article | ||||
DOI: 10.21608/erjm.2009.69388 | ||||
View on SCiNiTO | ||||
Authors | ||||
Z. M. El-Baradie1; A. A. Ibrahim2; I. M. Ibrahim2; R. A. Mahmoud3 | ||||
1Central Metalurgical Research and Development Institute (CMDRD, National Research Center, Cairo, Egypt | ||||
2Mechanical Engineering Department, Shoubra Faculty of Engineering, Bertha University, Cairo, Egypt . | ||||
3Aircraft Engine Factory, Arabic Association for Industrialization, Helwan, Egypt . | ||||
Abstract | ||||
HIgh carbon — high chromium cold work tool steel type D3 containing 2%C and 12% Cr was commonly used for manufacturing stamping tools. This paper introduces an investigation for the effect of inoculation ofthis type oftool steel by niobium. Four grades ofthis tool steel containing 0, 0.03%, 0.04% and 0.05% Nb were casted in an induction furnace at 1600°C. Different treatment processes including annealing, forging, stress relief, hardening, and tempering were carried out for the casted alloy. Examination via optical microscopy, X — ray diffraction, hardness test, tensile test, . and dimensional wear coefficient and wear rate measurements has been investigated. Furthermore the fracture surfaces were examined using SEM microscope. The tool steel containing both Nb carbides and Cr carbides exhibited a higher hardness, toughness, and wear resistance in ëomparison with tool steel containing only Cr carbides. On the other hand, the addition of Nb increased hardenability, and led to the refinement of the tool steel grain structure. The microstructtre observation revealed that the tool steel containing both Nb, and Cr exhibited fine and uniformly distributed metal carbides, while, the carbides were coarse and sparsely distributed in the tool steel containing Cr only. As niobium~ content increases, the improvement ofthe mechanical properties and wear resistance were observed. Fracture surface examination indicating that Nb addition and hardening followçd by tempering process lead to changing the mode of fracture from cleavage to quasi — cleavage mode. The highest wear resistance can be achieved by hardening followed by tempering of 0.05 % Nb tool steel. | ||||
Keywords | ||||
Niobium; inoculation; tool steel; Mechanical Properties | ||||
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