Foseco Non-Ferrous Foundryman’s Handbook Part 15 potx

Foseco feeding systems Introduction Foseco provides complete feeding systems for foundries, comprising: Sleeves – insulating and exothermic for all metals Breaker cores – to aid removal

than the pouring temperature) Read expansion or shrinkage (S)

expressed as a percentage on the horizontal axis

(c) Mould wall movement (M%) depends on the hardness of the mould and

can vary from zero for hard silicate or resin moulds to 2% for green sand moulds with a mould hardness of 85° (B scale) Add the mould wall movement from the expansion to give a final value of S If this is positive

or zero the casting will not need feeding

(d) The weight of metal in the feeder under consideration (WF) The total

weight of casting (WC) which can be fed from a feeder of weight WF

is

If the total weight of casting section (Wt) which requires feeding is

greater than WCthen increase the dimensions of the feeder until:

WT = WC

4 Calculate the dimensions of the feeder neck

(a) Top feeders

No calculation of feeder-neck dimensions are required If possible feeder sleeves should be used with breaker cores

(b) Side feeders

The required feeder-neck dimensions are obtained from the calculation

of the neck modulus (MN) by applying the ratios:

MC:MN:MF = 1.0:1.1 ST/100:1.2ST/100 then using either the endless bar equation (Fig 17.5 g) or the diagram in Fig 17.6

Foseco feeding systems

Introduction

Foseco provides complete feeding systems for foundries, comprising: Sleeves – insulating and exothermic for all metals

Breaker cores – to aid removal of the feeder from the casting

Application technology – to suit the particular moulds and moulding machine used

Aids to the calculation of feeder requirements

Range of feeder products

The Foseco range of products comprises:

Product

name

casting alloy

Remarks

KALMIN S Insulating Al, Cu base

iron, steel

extend solidification time by 2.0–2.2

KALMINEX

2000 Insulating andexothermic iron, steel extend solidification time by2.5–2.7 FEEDEX HD Highly

exothermic

iron, steel small riser-to-casting contact

area use where application area is limited

KALMINEX Insulating and

exothermic

iron, steel for large diameter feeders

KALBORD Insulating iron, steel

copper base

in form of jointed mats for large feeders

KALPAD Insulating iron, steel

copper base

prefabricated boards or shapes

KAPEX Insulating Al, Cu base

iron, steel

prefabricated feeder lids, replace hot-topping compounds

KALMIN S, KALMINEX 2000, FEEDEX HD and KALMINEX products are supplied as prefabricated sleeves in a wide range of sizes and shapes, with

or without breaker cores

KALMIN S feeder sleeves

By using a high proportion of light refractory raw materials, a density of 0.45 g/cm3is achieved, ensuring highly insulating properties KALMIN S

Figure 17.8 Foseco sleeve types.

Figure 17.9 Example of sleeve support on a moulding machine pattern plate.

Figure 17.10 An insertable KALMINEX sleeve with breaker core attached and a typical sleeve pattern.

Figure 17.11 The KALSERT system in operation KALMINEX sleeves being inserted into green sand moulds on an automatic moulding line.

sleeves are particularly suitable for aluminium, copper-base and iron alloy sand castings since the raw materials used are neutral to both the casting alloys and to the moulding sand KALMIN S sleeves are supplied as

“parallel conical”, “opposite conical”, or cylindrical sleeves for either

ram-up application or insertion into cope or drag, Figs 17.8, 17.9, 17.10 and 17.11 They can be applied in the following moulding systems:

Moulding method KALMIN S feeder sleeve type

Insert sleeves into the turned-over

cope mould especially in automatic

moulding lines

Parallel conical insert sleeves

in conjunction with Foseco Sleeve Patterns

Insertion of the feeder sleeve from

the top of the cope mould into the

cavity created by means of a suitable

sleeve pattern which is drawn after

moulding

Opposite conical sleeve

Ram-up on the pattern plate in a

machine moulding or a

hand-moulding operation

Parallel conical insert feeder sleeve, opposite conical feeder sleeve or cylindrical sleeve Insert sleeve in a vertically parted

moulding system

Parallel conical insert and/or opposite conical feeder sleeve Insert sleeves into shell moulds Parallel conical insert and/or

opposite conical feeder sleeve Application of feeder sleeves in a

drag mould over a feeder base or

bridge core

Parallel conical feeder sleeve

as floating sleeve system

KALMIN S feeder sleeves extend the solidification times by a factor of 2.0–2.2 compared to natural sand feeders of the same size From these results, Modulus Extension Factors (MEFs) of 1.4–1.5 have been calcu-lated Though KALMIN S feeder sleeves can give more than 33% of their feeder volume to the solidifying casting, it is recommended that a maximum of one-third of the feed metal volume should be fed into the casting so that the residual feeder modulus is adequate in relation to the casting modulus at the end of solidification For this reason, it is recommended to consider modulus as well as solidification shrinkage in order to determine the correct feeder Foseco provides tables allowing KALMIN S feeders to be selected with the desired modulus, volume (capacity) and dimensions

KALMINEX 2000 feeder sleeves

KALMINEX 2000 is a highly insulating and exothermic feeder sleeve material in the form of prefabricated sleeves for iron and steel casting in the modulus range between 1.0 and 3.2 cm For light and other non-ferrous alloys the KALMINEX 2000 feeder sleeve material is not recommended The manufacturing process specifically developed for this unique feeder sleeve material not only ensures a low density of 0.59 g/cm and, therefore, a high grade of insulation but also an additional exothermic reaction peaking at 1600°C Due to the strength of the KALMINEX 2000 feeder sleeves, they can often be rammed up directly on the pattern plate on many moulding machines

KALMINEX 2000 feeder sleeves can be applied in the following moulding systems:

Application method KALMINEX 2000 feeder shape

Insert sleeves into the turned-over

cope mould especially in

automatic moulding lines

Parallel conical insert sleeves in conjunction with FOSECO Sleeve Patterns

Ram-up on the pattern plate in a

machine moulding or a

hand-moulding system

Parallel conical insert feeder sleeve, opposite conical feeder sleeve or cylindrical sleeve

Insert sleeve in a vertically parted

moulding system

Parallel conical insert and/or opposite conical feeder sleeve Insert sleeve into shell moulds Parallel conical insert and/or

opposite conical feeder sleeve Application of feeder sleeves in a

drag mould over a feeder base or

on a bridge core

Parallel conical feeder sleeve as floating sleeve system

When determining the solidification times with KALMINEX 2000 feeder sleeves it has been found that they extend the solidification time by a factor

of 2.5–2.7 compared to a natural sand feeder of the same size From these results Modulus Extension Factors (MEFs) have been calculated between 1.58 and 1.64 Foseco provides tables allowing KALMINEX 2000 feeders to

be selected with the desired modulus, volume (capacity) and dimensions Under specific practical conditions it has been found that the KALMINEX

2000 feeder sleeves can render 64% of their volume to the solidifying casting When using feeders with the correct modulus it is necessary to take into account that the modulus of the residual feeder – if more than 33% of the feeder volume is fed into the casting – may not be adequate in relation to the

casting modulus towards the end of the solidification Therefore, it is essential to calculate shrinkage as well as modulus in order to determine the correct feeder sleeve

FEEDEX HD V-sleeves

FEEDEX HD V feeder sleeves are used for iron and steel casting alloys FEEDEX HD is a fast-igniting, highly exothermic and pressure-resistant feeder sleeve material The sleeves possess a small feeder volume, a massive wall, but only a small riser-to-casting contact area, Fig 17.12 They are, therefore, specially suited for use for “spot feeding” on casting sections which have a limited feeder sleeve application area The sleeves are located onto the pattern plate using special locating pins, the majority are supplied with shell-moulded breaker cores Owing to their small aperture, these breaker cores are not recommended for steel casting

FEEDEX HD V-sleeves are particularly useful for ductile iron castings since with their low volume shrinkage of below 3%, a modulus-controlled KALMIN or KALMINEX 2000 feeder will often have more liquid metal than

is necessary The very high modulus and relatively low volume of FEEDEX HDV gives improved yield In many ductile iron applications, the small breaker core aperture of the feeder means that the feeder is separated from the casting during the shakeout operation and the cleaning cost is reduced

Figure 17.12 FEEDEX HD V-sleeve.

Figure 17.13 The application of FEEDEX HD V-sleeves to ductile iron castings.

When used in ductile iron applications, it is important to note that the high temperature reached in the highly exothermic feeder can cause residual magnesium in the iron to be oxidised so that there may be a danger of denodularisation on the casting–feeder interface To avoid this, residual Mg should be greater than 0.045%, inoculation practice should be optimised and thick breaker cores used Note that when calculating FEEDEX metal volume, only 50% of the capacity should be assumed since part of the metal in the feeder will be lamellar due to oxidation of the Mg in the feeder cavity Figure 17.13 shows examples of the use of FEEDEX HD V-sleeves on ductile iron castings

KALMINEX feeder sleeves

KALMINEX exothermic-insulating feeder sleeves are used for all iron and steel casting alloys They are supplied with feeder diameters from 80 to

850 mm for the modulus range between 2.4 and 22.0 cm and are suitable for larger-sized castings

The manufacturing process specifically developed for this exothermic-insulating product and the selection of specific raw materials give a total closed pore volume of nearly 50% The excellent heat insulation resulting from the low density (compared with moulding sand) is enhanced by an exothermic reaction

When determining the solidification times with KALMINEX feeder sleeves it has been found that they extend the solidification time by a factor

of 2.0–2.4 compared to the natural sand feeders of the same size From these results Modulus Extension Factors (MEFs) of 1.4–1.55 have been found Under practical conditions it has been found that KALMINEX feeders when adequately covered with KAPEX lids or a suitable APC (anti-piping compound) may render up to 64% of their contents into the casting When using feeders with the correct modulus it is necessary to take into account that the modulus of the residual feeder – if more than 33% of the feeder volume is fed into the casting – may not be adequate in relation to the casting modulus towards the end of the solidification Therefore it is essential to calculate shrinkage as well as modulus when determining the size of the feeder sleeves

Foseco provides tables allowing KALMINEX feeders to be selected with the desired modulus, volume (capacity) and dimensions Several different shapes of KALMINEX feeders are available, Fig 17.14a,b,c Breaker cores are generally made of chromite sand, although they can be produced in silica sand

KALBORD insulating material

Although in theory there is no upper limit of inside diameter for using prefabricated feeder lining shapes for inside diameters above about 500 mm,

Figure 17.14 (a) KALMINEX cylindrical feeder sleeve with breaker core and KAPEX lid (b) KALMINEX TA sleeve.

Thickness Width

manufacture, transport and storage become increasingly inconvenient For this reason Foseco has developed KALBORD flexible insulating material in the form of jointed mats They can be easily wrapped around a feeder pattern or made up into conventional sleeves as required for the production

of insulating feeders for very large steel, iron and copper-based alloy castings, Fig 17.15

KALBORD mats are available with 30 mm and 60 mm thicknesses in widths up to 400 mm and lengths 1020 or 1570 mm Their excellent flexibility permits the lining of irregular feeder shapes The mat is most easily separated or shortened with a saw blade

Produced from high heat insulating materials, 30 mm mats achieve a 1.3 fold and 60 mm mats a 1.4 fold extension of the modulus It is recommended that KALBORD feeders are covered with FERRUX anti-piping powder

Figure 17.14 (c) KALMINEX oval sleeve.

Figure 17.15 KALBORD jointed mats.

22 300

KALPAD board 1001

500

300

KALPAD jointed mat 1002

500

45 140

r=420 KALPAD pad 1012

KALPAD prefabricated boards and shapes

KALPAD has been developed by Foseco to provide a lightweight, highly refractory insulating material to avoid metal padding and to promote directional solidification If KALPAD insulating shapes are used the desired shape of the casting need not be altered This increases yield and reduces fettling and machining costs For this purpose KALPAD is used in copper-based metal and steel foundries and particularly in malleable iron and grey iron mass production

Owing to a special manufacturing process and the use of alumina mineral fibres KALPAD shapes have a density of 0.45 g/cm3with more than 60% of the volume being closed pores which are the reason for the high insulation and refractoriness During pouring KALPAD produces only negligible fumes and behaves neutrally towards moulding materials and casting metals

When evaluating solidification times on KALPAD padded casting sections it has been found that they extend the solidification time by a factor

of 2.25–2.5 compared with conventionally moulded castings From these results Modulus Extension Factors (MEFs) of 1.5–1.58 have been calculated

It is recommended to use a factor of 1.5 if KALPAD shapes of 20–25 mm thickness are applied The dimensions of KALPAD boards and shapes are shown in Fig 17.16

Figure 17.16 KALPAD prefabricated boards and shapes.

KAPEX prefabricated feeder lids

KAPEX insulating feeder lids, Fig 17.14a, are an improvement over the hot-topping powders in foundry use, being dust and fume free and giving repeatable feeding results They can be applied to all feeders either exothermic, insulating or natural The lids have an insulator density of 0.5 g/cm3 and are purely insulating Owing to their neutral behaviour towards moulding material and casting metal they are used in light metal and copper-based foundries as well as in high alloy steel foundries KAPEX KALMINEX 2000 lids are also available

Breaker cores

Breaker cores for the reduction of the feeder-to-casting contact area enable feeders to be broken off or knocked off from many types of castings In the case of very tough casting alloys where it is not possible to simply break off

or knock off the feeder, the advantage of using breaker cores lies in the reduction of fettling and grinding costs for the removal of the feeder Besides the conventional types of breaker cores based on silica sand (Croning) and chromite sand, special breaker cores with a very small aperture are also in use in repetition iron foundries These special breaker cores as shown in Table 17.5 are made from highly refractory ceramic

Experience has shown that at least 70% of the breaker core area should be

in contact with the casting, in order to level out the temperatures of the metal and the breaker core from the superheat upon or before reaching liquidus

Some of the standard forms of breaker core available from Foseco are shown in Fig 17.17 Foseco feeder sleeves can be ordered with or without breaker cores attached

Table 17.5 Application of breaker cores

Breaker core

material

Casting metal Feeder diameter

(mm)

Silica sand Grey iron, s.g iron, non-ferrous metals 35–300 Ceramic Grey iron, s.g iron, non-ferrous metals 40–120