BCIRA copper cast iron.pdf


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Addition of copper to cast iron

What is the efiect of copper ?
Copper Incr6ases the lonslls slrength, hardno6s and wear,reslslanco of gley cast lron
by promoting a pearlitlc structure and reducing ths lree {enite content. Copper alSo
reducas lhe risk of chlll in thin secllons aod at lree edges, and is aboul on€ quarter as
eflecllve as slllcon.
Copper is sometlmes added to the pearlltlc grades o{ nodular (SG) iron to lmprovs
str€nglh and wear resistance. lt may also be usod as a partial replacement or substitute
for nickel in the abrasion-reslstant white martensitic irons and austenitlc irons (BS
3468:1961 Type AUS 101).

How much copper should be used ?
This will d€pend on castlng s€ction thickness and the incr€as€

.

In tensile sttength
required but for general guidance:
0.5-1.0 per cent in lrons lor llght sectlon castings.
1-2 per cent in irons for medium and heavy section castlngs whlch have slow
cooling rates in th€ mould, or where Oreater Increases in tonsll€ slrenglh ato
required in light seclion caslings.
l-2 p€r cent in combinalion with small amounts (usually 0.25-0.5 psr c€nt) ol
chromium and/or molybdenum when maximum tensile strength is needed.
Copper additions to g.sy lron in excess of about 3 per cent involvo the risk ol s€paration of lreo copper during solidification ol the iron In the mould, glving a reduction In
slrongth.
Fo, the productlon oI austenltic lron to BS 3468il961 Type AUS 101, an addltlon ol
5.5-7.5 per cent of coppoi is speclfied. In this type ol lron th€ coppsr remalng
completely in solution.

:
lncrease in tensite strcngth,
fot differcnt dlameter

as-cas, tes, ,a.s,
oblained by the addition
coppel

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