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The Carbide specifications top hammer defects elimination studies

Author: ZhouXuFeng
Tutor: WuEnXi；YuShaoWu
School: Central South University
Course: Materials Science
Keywords: Anvil Pore Crack Suppress Sintering
CLC: TF125
Type: Master's thesis
Year: 2004
Downloads: 177
Quote: 1
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Abstract


Carbide internal microscopic holes and other defects will aggravate the brittle fracture , carbide products , especially large size of internal defects more difficult to overcome . Proceed from how to achieve alloy high-density and high- intensity angle , system studies molding, sintering process carbide anvil of the preparation process and the various process parameters affect the regularity of the anti- fracture strength , and to explore the mechanism of the alloy internal defects eliminated . Process : ordinary uniaxial press slow and uniform pressure can be prepared better quality top hammer compacts involute mode approach to pre - load and ≤ 0.5 mm / sec in demolding can be avoided elastic The effect caused compacts crack . By pressing equation 1GP = 1gp_max - L ( beta -1 ) , that , to prepare the ideal dense Unit top hammer compacts isostatic pressing pressure can meet requirements and enable the compacts parties direction uniform dense . The paraffin process large products top hammer in the dewaxing stage , 270 ℃ -400 ℃ the molding agent paraffin removal stage gas release peak at 400 ° C -750 ° C , in the dewaxing calcining stage set reasonable process parameters can be prevented alloy crack , but compacts itself there are micro - cracks will inevitably emerge affect product quality . Top hammer big products capillary pressure in the high-temperature sintering resistance Pr , this paper calculated the capillary resistance Pr = 3.96 × 10 6Pa , the pressure sintering Pressure P = 5x10 6Pa gt ; Pr sintered body pores can be eliminated. Alloy from 1420 ℃ to 1300 ℃ to 13 ℃ / min rapid cooling process allows pore length 2a reduce tension surface to defect from △ t increases, rapid cooling is equivalent to reducing the alloy in high temperature insulation , suppression WC abnormal growth the alloy WC grain size is relatively uniform , thereby increasing the strength of the alloy .

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CLC: > Industrial Technology > Metallurgical Industry > Metallurgical Technology > Powder metallurgy (metal ceramic technology ) > Powder metallurgy products and their applications
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