paper de fundicion centrifuga (centrifugal casting)

7/21/2019 Paper de Fundicion Centrifuga (Centrifugal Casting)

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CENTRIFUGAL CASTING FOR UNPRESSURIZED FABRICATION OF

LOTUS-TYPE POROUS COPPER

Abstract

Conventional methods to fabricate lotus-type porous metals utilize pressurized hydrogento control porosity and pore size. Here we present an alternative technique utilizing

centrifugal casting under hydrogen pressures similar to atmospheric, where the porosity

and pore size are controlled by the rotational velocity. In verification experiments,

molten copper was poured into a mould at rotational velocities of !!"#!!! rpm under a

hydrogen gas pressure of !.# $%a. &he results confirmed that porosity and average pore

diameter can be controlled by varying the rotational velocity without the need for

pressurized gas. It is concluded that the centrifugal casting technique is a promising

method for safe and economical manufacture of lotus-type porous metals.

Highlights

' &he lotus-type porous copper can be successfully fabricated by centrifugal casting.

' %orosity and pore size can be controlled by the rotational velocity.

' %orosity and pore size can be controlled without hydrogen pressurization.

!"#$r%s

• %orous material(

• )irectional solidification(

• Copper(

• Hydrogen(

• Centrifugal casting



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SIMULATION STUDY ON THE CENTRIFUGAL CASTING WET-TYPE

CYLINDER LINER BASED ON PROCAST

Abstract

&he casting defects that appear the inside surface of a wet-type cylinder liner 89&C:;,

such as macrosegregation and shrin<age holes, are important factors that affect the

quality of the 9&C: produced by centrifugal casting. &o reduce these defects, a model

of centrifugal casting 9&C: based on the %roC2& software was constructed in this

study, and the simulated result was used to optimize the casting process. &he

temperature field of the casting 9&C: was simulated based on actual solidification, and

the solidification process and casting defect were analyzed. /esults show that the

simulated temperature field is in accordance with the actual process and the casting

defects appear in the final solidification zone and inside the sub-surface near the thic<-

wall side. &hese defects were later revealed on the surface after machining. &he factors

that affect the temperature field and the solidification process, such as the cooling-down

method, mold structure, coating material, and coating structure, were also analyzed.

ased on these analyses, an improved method was proposed.

Highlights

• &he model for a horizontal centrifugal casting is established used %roC2&.

• &he effects of technological parameters on defect area were investigated.

• &he difference in coating thic<ness has a significant influence on the temperature

filed.

• n optimized schedule was designed to guide the improvement of the actual

process.

Keywords:



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MODEL E;PERIMENT OF MOLD FILLING PROCESS IN <ERTICAL

CENTRIFUGAL CASTING

Abstract

y using centrifugal governor, high-speed camera, and liquid as well as acryl glass

molds to simulate the filling process of &itanium alloy melts. /esults show that the

liquid stic<s to one side of the runner wall 8or cavity wall; to fill and the side is opposite

to the rotational direction. &he whole filling process is divided into two sections, one is

forward filling and the other is bac< filling. +xperimental results show that bottom

filling is better than top filling in that the former can realize stable filling, avoiding

liquid crash in the cavity. &he free surface of liquid is cambered li<e in the cavity and the

runner, whose center is the rotational center.

!"#$r%s

• Ce

ntrifugal casting(

•

=illing ability(

• H

ydraulic simulation(

•

ottom filling

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AD<ANTAGES OF THE CENTRIFUGAL CASTING TECHNI=UE FOR THE

PRODUCTION OF STRUCTURAL COMPONENTS WITH AL>SI ALLOYS

Abstract

&his wor< discusses the mechanical properties advantages of using the vertical

centrifugal casting technique for the production of structural components when

compared to traditional gravity casting. n analysis of the most important features that

occur in mechanical properties due to the centrifugal force is made. comparison of

mechanical properties of specimens obtained by both centrifugal casting technique and

gravity casting technique is made.

It is observed that the centrifugal force may increase rupture strength in @75A, and

rupture strain in about #3!A over the gravity casting technique. &he Boung modulus

also increases in about #A. &he fatigue life experiences an increase of about #.5!!A

and the fatigue limit increases in about ?5A. &he centrifugal casting process is,

therefore, much more effective in terms of obtained mechanical and fatigue properties as

compared to gravity casting.

&he previous effects vary within the casting, according to the relative position from

where the specimen is ta<en from the casting. &he higher the distance in relation to the

rotation centre 8higher centrifugal force or higher D; the bigger the increase in

mechanical properties. &hus, a functional graded material, with properties changing

along one axis is obtained. &his effect may be useful for the production of components

where different specifications are needed in different parts of the component.

n example of a potential application is an engine piston. In this paper it will also be

shown how this technique would be very advantageous for the production of these

structural components.

!"#$r%s

• Centrifugal casting(

• l"2i alloy(

• $echanical(



• =atigue properties

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MICROSTRUCTURE OF TWO CENTRIFUGAL CAST HIGH SPEED STEELS

FOR HOT STRIP MILLS APPLICATIONS

Abstract

High speed steels 8H22; present excellent hardness, wear resistance and high-

temperature properties. &hese mechanical properties are due to the presence of a great

amount of hard carbides in the martensitic matrix. In the last #! years, Eapanese

rollma<ers have developed H22 grades and introduced them into hot strip mills.

&he $arichal Fetin society 8:iGge, elgium; has developed two grades of H220 Fosmos

and urora. oth grades present interesting properties but urora shows overall better

performance than Fosmos, mainly because of a better distribution of harder 8$C and

$C; carbides in the martensitic matrix. $oreover, the hardness of the urora grade

stays constant in depth and can be strongly improved by heat treatment, due to

secondary hardening.

&he purpose of this wor< is to describe the microstructure and the mechanical properties

of the Fosmos and urora grades by various techniques such as optical microscopy,

scanning electron microscopy 82+$;, and macrohardness measurements.

Highlights

' &he structure of two H22 grades 8Fosmos and urora; was characterized.

' &he effects of heat treatments on the structure were studied.

' &he urora grade presents secondary hardening due to the presence of very fine $ C

carbide.

' &he hardness of the urora grade is not influenced by depth in the part.

' &he intrinsic hardness of $C carbides was measured by nanoindentation.



!"#$r%s

. =errous metals and alloys(

C. Casting(

D. $etallography

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FABRICATION AND CHARACTERI?ATION OF BSCCO-//1/ TUBE

PREPARED BY CENTRIFUGAL CASTING

Abstract

9e fabricated a 2CC-# 8#; tube by the centrifugal casting process for the

application in a fault current limiter and evaluated the effect of the processing variables

on its microstructure and superconducting properties. 2pecifically, the effects of the

preheating temperatures of the mold and the rotating ingot in the mold on the

microstructure, texture, and critical current 8Ic; were characterized.

9e observed that the formability of the tube was dependent on the mold temperature and

the optimum temperature was found to be 5!!"3!! C. 9hen the ingot was annealed at

!! C for #! h, the Ic was measured to be 74"?5! at 44 F. &o improve the I c value

still further, we modified the centrifugal casting method such that the ingot was rotated

in the mold at 4!"! C, followed by annealing. &he I c of the tube was increased to

34"! and this improvement was probably due to its larger grain size and more

preferred orientation based on the pole-figure and 2+$ analyses.

!"#$r%s• 2CC-#(

• Centrifugal casting(

• Critical current(

• $icrostructure(

• &exture

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paper de fundicion centrifuga (centrifugal casting)

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