#3 Installations Lessons Learnt 12/03/16

Installations Lessons Learnt

What do I want, as a supplier, when it comes to an installation? In short, to walk away from a completed installation leaving a satisfied customer and with that little warm feeling inside knowing that it’s a job well done.

All installations obviously have to be completed so can be deemed successful to some degree but there are good and bad installations. With the good ones, you get cooperation between everybody, it all goes as planned and, if you’re lucky, the chance for a beer to clear your throat after a long and successful day on site.  The bad ones give you something to talk about over several beers many years later.

There are a number of points that I’d humbly suggest can help make the installation process less painful to both the foundry and the supplier.

I’d say that the key to a successful installation is good communication with all the involved parties starting at the beginning when the project exists as a design concept and following all the way through to the final installation stage.

To borrow a military term, a chain of command needs to be established with the foundry placing itself at the head of that chain and, if necessary, creating a temporary team to act as project engineers. Even if the project is of such a size that an external foundry consultancy group is brought in to manage the project, it is my experience that the project will go smoother if the foundry keeps overall control of the project especially when it comes to the installation stage. I’ve worked closely, and successfully, with other suppliers on many installations and we all want the same result but sometimes the requirements of suppliers can clash, especially when different installation teams are working in the same area, all needing access to restricted resources such as lifting equipment or even power points. If such a situation arises then the foundry needs to be the ultimate arbitrator.

Further to this that surprising as it may seem, I’ve found that not all projects always have the 100% support of everybody at the foundry.  Some foundries, dare I say it, can have an internal politics issue which we, as an outsider, can be unwittingly be drawn into. It doesn’t often happen but when it does it can make the job much harder than it needs to be.  One major molten metal handling installation at a leading foundry, in the late 1990’s developed into a nightmare when we found ourselves caught up in an ongoing power struggle between two of the foundry’s directors. One of the directors had been the major driving force for improving the molten metal handling but the other clearly didn’t want it, preferring to stay with the system they already had.  A situation that should have been resolved back at the consultation stage and not left to fester up to the point of installation. The handling system was designed to improve several existing issues the foundry had covering metal treatment, transfer and pouring. However, it did require a significant change to the way that the foundry had been working up to that point. We thought that everybody was on board with the project, having discussed the proposed changes extensively with the foundry at the initial design stage, but when we got on site soon found out otherwise. The foundry management was split into factions and cooperation very much depended on which camp we were talking to. The installation was only completed by putting in some very long hours and we were glad to leave.

Both directors have long since moved on and we are still a supplier to the foundry. We get on much better with the current management team.

I also accept that we can’t always count on having the foundry’s workforce on our side. Replacing an obsolete system will improve efficiency and working conditions but this sometimes this doesn’t go down too well with the people who have to use the equipment. At best they may have to learn to do things in a different way and at worst somebody might lose their job. For example; we installed an overhead monorail system into a foundry where they had been transporting and pouring metal using hand carried crucibles. It was hard physical work and, due to the effort involved, the foundry had previously used three teams who were rotated. The new monorail allowed larger amounts of metal to be both transported and poured much more safely and with much less effort. So much less effort that the foundry then only needed one team to do the work that had required three teams.  Didn’t make us popular with everybody.

There is also the need for the foundry to allocate realistic time for the installation.

I’ve overseen several installations at new “greenfield” sites where each suppler can be brought in as and when required but I understand a new greenfield installation usually has the luxury of an extended timescale that a working foundry simply cannot afford.

So we accept that most foundry installations have to fit within limited shutdown periods such as holidays.  Which can lead to several different projects being scheduled for installation at same time, and often in overlapping areas.  With goodwill on all sides and good communications any potential problems can be minimised but the foundry has to be realistic about what can be achieved in the time allocated.  It’s probably not a good idea for a foundry to decide to wreck out and reline furnaces or to re-route the dust extraction ducting if other installation teams have to work in the same area.

The bottom line is that we all want to get the job done to everyone’s satisfaction. The majority of installations go well in no small part to the foundry’s own workforce. So I’d like to finish by saying thanks to all those foundry maintenance departments that have played an important part in all our successes.

 


#2 Foundry Ladle Maintenance and Trouble Shooting 10/10/15

Foundry Ladle Maintenance and Trouble Shooting

In many foundries the ladle is still the most common method for transporting and pouring molten metal.  Compared to many other pieces of foundry equipment, the typical ladle is still a fairly basic item with a design that hasn’t changed greatly for decades. A workhorse of the foundry, it is expected to work when required, day in and day out, without fuss or drama.  As such it is often taken for granted, overlooked until something goes wrong, and only getting attention when either production and/or safety is compromised.

The purpose of this article is to therefore give some guidelines on how a foundry can get the best use out of their ladles, and avoid unexpected breakdowns.

Much of what follows is common sense, and will already form part of a good foundry practice but it doesn’t hurt to be reminded. (Hopefully avoiding grandma and egg sucking along the way).

The Right Ladle for the Right Job

General ladle maintenance and trouble shooting is simpler if the basics are right to start with and the ladle is designed for the actual purpose it is used for. It is appreciated that over the years many foundries build up a stock of ladles, usually of different types and often in various states of repair. Typically only a few of the ladles may get regular use with the rest being held in storage on the off chance that one day they might be needed.

Therefore , if you are looking at changing or adding to your casting process it may seem unnecessary to get a new ladle especially if your spare ladles look like they could be used but this can be false economy as it is better, and safer if the right ladle is used for the right job.

The ladle should be sized for the intended working capacity plus safe freeboard for a given refractory lining thickness. You should never fill a ladle to the brim either by accident or to squeeze a bit more capacity out of the ladle. This is especially true with ductile treatment ladles that have extended freeboards to contain the treatment reaction and, if over filled, can hold much more than their rated capacity. Ladles are designed with safety margins but this margin may vary from manufacturer to manufacturer and should not be used to allow a ladle to be persistently overfilled.

Over filling can upset the balance and handling of the ladle, and can also lead to accelerated wear on parts such as the gearbox and trunnions. Ladles should therefore be filled in a way that the contents can be measured and quantities known.

Conversely it is not good practice to use an over sized ladle. If you have a 2t capacity ladle going spare but find that you only need 1t capacity then it’s not advisable to use the 2t ladle only half full. The ladle is going to be bottom heavy, difficult to rotate and wear rates will be increased.

Match the Ladle to the Refractory Lining

If you are looking to purchase new ladles, then discuss your refractory lining requirements with your ladle supplier as well as your refractory supplier.  It is not my place to tell you what type of refractory or which refractory supplier you should use but it is my job to make sure that the ladle offered is designed to work most effectively with the refractory lining you wish to use.

One of the basics is to make sure that the ladle shell is sized to give the working capacity for the refractory lining used. In the past many ladles used to have firebrick linings which are typically half the thickness of today’s castable concrete refractories. If the ladle shell isn’t sized for a castable concrete refractory but is still sized on a firebrick lining you could find that the working capacity of the ladle is significantly reduced and that the freeboard is compromised.

There are also a number of details that can be added to a ladle design, usually with very little additional cost, that can make the wrecking out and relining of ladles much quicker and easier for your maintenance crew. Detachable bottom sections or push out base plates can greatly reduce the time it takes to remove a heavy-duty castable concrete lining, avoiding the need for prolonged use of power hammers, freeing up personnel and quickly recouping the additional cost of the ladle.

It also helps if you have the time to let the ladle cool down before wrecking out the lining. It is not uncommon to see ladles with patched or distorted shells where the hammer has either punctured through a shell or has created a bulge that then acts as a lining anchor making the refractory removal harder. In extreme cases the ladle shell can become so deformed that new lining cannot be safely fitted.

One other point to be aware of with regard to ladle linings is if you send the ladle off to your refractory company to have a new lining fully dried in an oven then the ladle gearbox and sidearm assemblies should be first removed. Soaking a complete ladle at temperatures of 120°C (248°F) and above for an extended period during the drying cycle will damage the bearings in the gearbox rendering the gearbox inoperable.

Initial checks with a new ladle.

Before a new ladle is brought into service, check that all the lubrication points are properly greased and that the gearbox has the correct amount of oil in it. The ladle handbook will show all the grease points and give information on the correct type of lubrication to use.  Check that everything is working mechanically, especially the safety catches.  Suspend the ladle and fully rotate it. This will also help to distribute the lubrication around the moving parts.

Follow your refractory company’s instructions for installing a new lining.

Maintenance and Troubleshooting your Existing Ladles

Due to their purpose, ladles are designed with a high safety factor. However this does mean that a ladle can often still carry on working, apparently OK, despite suffering from either prolonged neglect, damage or a combination of both. This can unfortunately mean that when the ladle does finally fail then this can be catastrophic with potentially dangerous consequences. The best and most simple way to avoid this is to carry out daily safety checks, before the ladle is to be used so that any potential problems can be spotted at an early stage and action can be taken without safety or production compromised.

Daily ladle checks

The ladle handbook will give a list of safety checks, some of which will be specific to the ladle, that should be carried out but the basics are as follows:

Carry out visual checks before the ladle is brought into service and when the ladle is cold.

Does anything look damaged, especially suspension parts such as the sidearms, lifting bail and hook?

If so, then don’t use the ladle and get it fixed.

Are the safety catches functioning correctly?

With the ladle on the ground try to rock the ladle sidearm; does the movement seem excessive? This is down to “feel” and it is difficult to give accurate guidelines as to what is acceptable as this is likely to be different for each type of ladle. However if you know your ladle you should be able to tell if the amount of backlash indicates that something is worn.

When the ladle is picked up by the overhead crane do the sidearms/lifting bail assembly visibly move as the slack is taken up in the sidearm bearings? (If so then the sidearm bearings definitely need changing).

Does the handwheel shaft move around in its housing? If so then the bearings are worn and it will be difficult to control the ladle pouring action.

With the ladle suspended, rotate the ladle in both directions. It is normal for the effort required to change as the ladle centre of gravity changes but the rotation should feel smooth with no jumping of the gears.

Is there excessive backlash in the gears?

The gearbox should be able to hold the ladle at any degree of rotation. If it doesn’t then the gearbox needs to be stripped down and examined.

After Use

Check for any signs of damage.

Keep the ladle clean and remove any metal splash build up.

 

Ladle Maintenance

Like all maintenance tasks this is best done as planned maintenance rather than in response to a breakdown.

The ladle handbook will have instructions on stripping down the ladle and examining the gearbox etc. This should be done periodically and be dependent on the usage that the ladle gets rather than simply following local regulations. If the ladle is used on a 3 shift basis 6 days a week then it will need more regular full inspections than if the ladle is only used once or twice a week.

General Ladle Handling

One of best ways of maximising the ladle life is to make sure that the ladle is correctly handled at all times, not just when the ladle is in operation but also during maintenance periods.

For example, if a ladle is to be handled by a fork lift truck (FLT), even for general handling rather than production purposes, the ladle design should reflect this and the ladle should have fork pockets incorporated into the design. Ideally these pockets should be on the ladle body. If a ladle is picked up under the ladle bail by a FLT and transported, the rocking motion transmitted back to the gearbox can, over time, cause accelerated wear and/or damage to the ladle gearbox, including shearing of the sidearm arm where it connects to the lifting bail.  If foundry needs to transport a ladle in this way then fitting an additional sidearm safety catch to the ungeared sidearm can counter this rocking.

Rotating the Ladle Bail when the Ladle is sat on the ground.

There is often a need to rotate the ladle bail clear of the top of the ladle when the ladle is placed on the ground, typically during maintenance or if the ladle is to be pre-heated.

This creates two issues that the foundry needs to be aware of.

Firstly the ladle gearbox is effectively working in reverse to how it is designed to operate and the loading imposed on the gearbox and ladle drive trunnion will be greater than when the gearbox is used to rotate the ladle shell. This can lead to increased wear on the gearbox and especially the drive trunnion. If unchecked, and in extreme cases, this can lead to the failure of the gearbox and/or drive trunnion resulting in the uncontrolled descent of the lifting bail.

Ideally the ladle lifting bail will be supported at all times but this may not be practicable therefore the ladle design can be adapted to minimise this issue. Additional safety catches can be added so that the lifting bail is locked at the rotated angle and, if necessary, counter weights can be added to the sidearms to minimise the reverse loading on the gearbox.

A second issue is that a great deal of care has to be taken if an overhead crane is used to assist in returning the lifting bail to the vertical. It is very easy for the crane to “get ahead” of the gearbox so that the crane is effectively pulling the lifting bail against the gearbox. This can also cause damage to the gearbox.

Conclusion

Ladles are the basic workhorse of the foundry providing the critical link between the furnace and the moulding line. A small amount of regular TLC will ensure that your ladles give safe, reliable and efficient service every time you use them.

Steven Harker

Technical Director

Acetarc Engineering Co. Ltd

www.acetarc.co.uk


#1 Defects Prevention 01/04/2015

Defects Prevention through Proper Metal Transport and Ladling

By Steven Harker, Technical Director Acetarc Engineering. Co. Ltd

There’s an old Irish joke, probably also claimed by many other countries, where a English tourist, lost on the back roads of Ireland, asks a local for directions on how to get to a scenic village, to which the Irishman replies “Well if I were you, I wouldn’t start from here.”

I’m not sure how far around the world the joke travels, but over time I’ve come to think that behind the Irish whimsy  there’s a lot of wisdom buried in the punchline.  Basically if you are starting out from the wrong place you are just going to make it harder for yourself to achieve your goal.

The problem for many foundries is that they do not have a choice in where they start from when it comes to producing castings. They have to deal with what they have got, here and now, but foundries, especially if they are a long established business grow and develop over decades.  Adapting existing work methods or bringing new processes to meet the demands of changing markets means that a typical foundry today is trying to achieve production targets while often working within constraints laid down many years ago.  This is compounded by the need for ever greater efficiency and cost reduction.

Moving to a new purpose built production facility, with all new equipment, and where everything is designed for maximum efficiency, while a nice idea; is not an option for most foundries. Therefore, the alternative is to look at what can be done to get the most out of a foundry’s existing set-up and equipment.

Speaking as a foundry equipment supplier, I would say that it always helps to invest in new equipment whenever possible.  This isn’t just self-interest as even the design of the humble ladle improves over time, and if a foundry is using worn out or obsolete equipment then they are just making life harder for themselves. However much can be achieved by first looking at what you have and seeing if it can be better used.

Since safety should be the priority when handling molten metal, assume that it’s a given in the following comments to avoid repetition. I’ve also limited the following to ladles but many of the points can be applicable to other foundry systems.  I’d therefore like to take this opportunity to highlight some areas where attention to molten metal transportation and pouring, can have an impact on defects prevention and scrap/waste reduction in a foundry.

Metal Distribution & Handling

The purpose of a ladle is to transport molten metal and pour molten metal safely and efficiently.  Whatever method used to transport the ladle must be able to deliver the molten metal from the melting/holding furnace to the point of discharge quickly so that temperature losses are minimized. If your metal delivery system can’t do it then you are already getting off to a bad start.

Sometimes the defects caused in castings are due to poor metal handling/ pouring will get put down to issues with the moulding process. However checking that your metal handling & pouring are working efficiently won’t do any harm and should prove cost effective.

 Molten Metal Temperature

Ideally molten metal tapping temperature at the primary melter or holding furnace should be as close as possible to the required pouring temperature.

Sometimes, due to the foundry layout and/or the need to carry out other operations such as in-ladle ductile iron treatment process, unavoidable temperature loss in the ladle can become an issue and the window of time during which the metal is usable can become restricted.

As the metal cools, its fluidity decreases which reduces the ability of the metal to flow into all parts of the mold (misrun) and can lead to other defects such as cold lap (cold shut) and some types of gas porosity defects.

The obvious solution is to make sure that the molten metal is delivered to the molding line when it’s at a temperature where it can be used. The point to remember here is that it is not the first mold cast but the last one in the run that is important.

One of the most commonly listed solutions to cold metal is to “superheat” the metal to compensate for the temperature losses. However in these energy conscious times this is quite a wasteful solution and should only be done after other options have been considered and the cause of the problem fully understood.

Using excessively hot metal can in itself also be a cause of casting defects such as:

  • Sand burning
  • Internal shrinkage cavities
  • Poor surface finish

 General Ladle Handling

Firstly look at the ladle handling and see if it can be improved.  Much can be achieved in the typical foundry by careful attention to the ladle handling procedures. Good organization of the foundry metal handling system can result in significant energy savings and casting defect reduction with lower scrap rates, and better consistent casting quality, without the need for capital equipment purchases.

  • Are there any bottlenecks or obstructions on the route that can be removed?
  • If you are moving the ladle by crane or monorail, can the travelling speeds be increased without raising safety issues?
  • If the ladle is being transported by a fork lift truck, is the ladle designed for that purpose? A ladle that is to be used with a FLT should have an extended freeboard to guard against the metal slosh while enabling the FLT to still travel at a safe and reasonable speed.
  • Can the route be made limited access so that other people don’t cause delays if they pass through?
  • Can the exchange of metal between transfer (bull) ladles and casting ladles be avoided?

The exception is where the transfer (bull) ladles are relatively large, and transfer distances are long with the transfer ladle being used to fill several much smaller casting ladles.

  • Is the ladle the right size? It’s better practice to use the largest practicable ladle size for both transfer and pouring.
  • Can the ladle design be changed to reduce temperature losses? Ladle shells can be sized to accommodate both a working refractory lining plus an insulation backing layer that can result in significant reduction in temperature loss.
  • Can the ladle be fitted with a cover to aid heat retention?
  • If ladles are used intermittently, can they be put under a pre-heater to maintain temperature when not in use?

Ductile Iron Treatment Ladles

If the ladle is used for a treatment process, is this process causing a significant temperature loss either through the process reaction itself or through the time taken to complete the treatment process, including slagging off operations etc. If so, can you change the treatment ladle method? Covered treatment ladles such as the tundish type and teapot spout treatment (mod-tundish) designs have significantly reduced temperature loss when compared to the open top (sandwich) process. Using the wire feed treatment method can reduce temperature losses but this may be due more to using ladles specifically designed for the wire feed process rather than due to the actual process itself.

It can greatly assist the quality and consistency of the treatment process if the ladle can be charged with the correct proportion of additives with respect to the amount of metal to be treated.  Throwing a couple of bags in and then one for good luck isn’t perhaps the best way. Also if a timer system can be set up to give the ladle operatives warning if the metal hasn’t been poured within a set time and there is a danger of fade occurring. This allows them to pig off the metal rather than pour suspect castings.

Ladle Pre-heating

Correct pre-heating of the ladle prior to use and during interruptions in production, can help eliminate the risk of random ladles with “cold” metal being poured.  The use of a correctly designed ladle pre-heater is also much more efficient when compared to open ended gas pipes, resulting in lower gas usage.  A well designed pre-heater will have its own combustion fan which gives better efficiency and control, avoiding the need to use expensive compressed air.

Although not as common due to the popularity of modern castable refractories, if ladles are used with a lining that has a high moisture content, such as a “wet” ganister mix or a naturally bonded sand mix and are not properly dried, there is a risk of hydrogen pin-holing occurring as the metal becomes contaminated by the hydrogen given off from the moisture.

Ladle Maintenance – Slag & Dross Inclusion

Ladles should be used with a good quality refractory lining which should be kept clean with any slag/dross removed between refills.

Teapot spout ladles and bottom pouring ladles should have a lip-pour spout fitted so that any residual metal and molten slag can be poured out of the ladle without contaminating the teapot spout neck or the bottom pouring nozzle.

Any slag or dross on the external surfaces of the ladle should be removed as soon as the ladle is taken out of service and not left to build up.

Ladle Pouring & Maintenance

The ladle operator must have complete control over the rotation, and thereby the pouring, of the ladle at all times to be to ensure consistency and quality of casting. Therefore ladles should be correctly maintained with special attention paid to the gearbox and any worn or damaged parts replaced.

The pouring rate in which the molten metal is introduced into the mold has to be fully controllable If not then, at best, scrap metal will be created through over-pour and spillage while at worst the casting will have defects rendering the casting as only good for scrap.

If the ladle gearbox is badly worn or damaged it may be possible for the ladle to continue rotating a little after the operator wants to stop, resulting in uncontrolled flow of the metal into the mold, and usually all over the top of the mold as well.

If the molten metal enters the mold too quickly, and in too large amounts, turbulence can be created in the metal flow which can lead to mold erosion, sand inclusions and casting porosity.

Ladle spouts often erode through contact with the molten metal and these should be kept in good condition to maintain accuracy of pouring.

Metal Waste Reduction

Metal waste used to be seen as not too big an issue since it all went back in the furnace and got recycled but as energy and labor costs only go one way, this view is not sustainable.  The old practice of “washing out” a ladle with molten metal to quickly pre-heat it and then pigging off the cooled metal would be considered very wasteful today (and frowned upon by the refractory suppliers).  Much more interest is now being shown by foundries in accurately controlling the metal poured into a mold so the amount of metal in the pouring cup can be minimized with no overfill and definitely no spillage. As discussed above, reducing metal wastage due to the metal either being too cold to pour, or, in the case of ductile iron, due to fade can result in significant energy savings.

Conclusion

Often without realizing it, many foundries waste energy and create higher amounts of scrap than they need to by having a molten metal handling and pouring system that is not operating as well as it could, resulting in casting defects and higher than necessary wastage.  Correct pouring temperature of the metal is critical to achieving good consistent result. Cold metal results in casting defects and higher than necessary metal wastage while hot metal results in casting defects and increased energy costs; a  lose /lose situation.

As I hope I have outlined above, many improvements can be made, often at little or no cost to the foundry, that help minimize or eradicate many of these issues.

Steven Harker, Technical Director Acetarc Engineering. Co. Ltd


Acetarc Videos & Downloads

Acetarc Videos & Downloads

Acetarc brochures, leaflets and general information to download.

Acetarc foundry ladle flyer
- Russian

Foundry Related Downloads

Acetarc Videos & Downloads 1

Acetarc foundry ladle lip-axis pouring brochure 2013

Download
Acetarc Videos & Downloads 2

Acetarc foundry ladles general specification document

Download
Acetarc Videos & Downloads 3

Acetarc general foundry ladle brochure 2013

Download
Acetarc Videos & Downloads 5

Acetarc foundry ladle flyer
- Polish

Download
Acetarc Videos & Downloads 6

Acetarc foundry ladle flyer - French, German, Spanish

Download
Acetarc Videos & Downloads 7

Acetarc foundry ladle flyer
- English

Download
Acetarc Videos & Downloads 8

Acetarc foundry ladle motor drive brochure 2013

Download

General Engineering Downloads

Acetarc Videos & Downloads 9

Allan Green (Acetarc) capacity
2p flyer

Download
Acetarc Videos & Downloads 10

Acetarc Heritage Railway Engineering Flyer

Download
Acetarc Videos & Downloads 11

Acetarc vehicle inspection pit
2p flyer

Download

Acetarc Video

Videos

Acetarc lip axis pouring SMI foundry complete cycle

Acetarc foundry ladle motorised drum receiver and monorail

Acetarc foundry ladle pouring

Acetarc Video


Parts for Classic Vehicles, Machinery & Structures 18

Parts for Classic Vehicles, Machinery & Structures

Parts for Classic Vehicles, Machinery & Structures

Parts for Classic Vehicles, Machinery & Structures 12

We pride ourselves on our ability to cover a wide range of projects, repairing, restoring or replicating parts for classic vehicles, machinery and structures.


From individual gears through to complete assemblies. We can use the original parts as a template, work off drawings or even produce manufacturing drawings where necessary.

Contact our office for further details.

Do you have a question about Acetarc?

We can help. Complete the form below and we will be in touch shortly.

Gallery


General Engineering

Click on any of the ladle images below to find out more!

Inspection Pit

General Engineering 19

Materials Handling

General Engineering 20

Monorail & Crane Systems

General Engineering 21

Steel Fabrications

Water Industry

General Engineering 22

Canal Boats & Waterways 29

Canal Boats & Waterways

Canal Boats & Waterways

Canal Boats & Waterways 23

Acetarc Engineering, a family owned and run company, are proud to offer our skills and capabilities to people and societies who have a need for heritage engineering projects.


From bespoke replicas from the age of steam and canals to parts for classic vehicles, we pride ourselves on our ability to cover a wide array of projects. Restoration, replicating or repair, either working to original drawings and sketches or working from the original item. We have carried out many projects for the Keighley and Worth Valley Railway (Kwvr). Past projects have included the manufacture of a new 5500 gallon tender tank for locomotive No. 34092 City of Wells, manufactured against original drawings supplied by the National Railway museum in York.

Do you have a question about Acetarc?

We can help. Complete the form below and we will be in touch shortly.

Gallery