Crushing, Screening & Conveying

Crushing, Screening & Conveying 2017-04-04T06:57:13+00:00
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Jaw Plate Failure and Life (10 replies)

Bob Mathias
2 years ago
Bob Mathias 2 years ago

What is the root cause of jaw plate that has a very short life span, failure rate is bad. I hope we can improve the liners life, I will inform you all if their is a progress on our Jaw liner. thank you so much.

Helena Russell
2 years ago
Helena Russell 2 years ago
1 like by vijay

The abrasion index of the material, the feed presentation and size of feed and profile of the jaw all have an impact on wear. If you send me a photo or sketch of the wear pattern I am sure I can offer you some additional advice

Tony Verdeschi
2 years ago
Tony Verdeschi 2 years ago

We cannot rule out the manganese Jaws themselves as being poorly manufactured i.e. incorrect methods/risers, poor chemistry control and or Heat Treatment issues. We at crushing Equipment would be happy to assist as advised by Helena.

JohnnyD
2 years ago
JohnnyD 2 years ago

How have you bench-marked the performance of the liners you are using. Do you have any historic Tonnes per liner data? Has the feed source changed? Have you changed jaw liner suppliers? Has your liner supplier changed the Manganese content of the liners supplied?

David Kano
2 years ago
David Kano 2 years ago

There have many causes to make jaw plate short life. It mainly depends on your rock hardness and your crusher working conditions (wet, dry, etc.). You should make sure the jaw plate you bought is good quality. Usually our customer use Mn18% with Cr2%. In order to help customer to improve the jaw plate's lifetime, we have our special material with 20 years experience, such as adding some % Molybdenum with special heat treatment, the jaw plate can increase about 20% lifetime. Hope this can help you.

Bill Fraser
2 years ago
Bill Fraser 2 years ago

The comments you received so far is spot on. Jaw plate wear is dependent on the type of material you are crushing and other variables like material size. You will want to reduce the amount of fines that enter into the crusher like with the use of a grizzly feeder. Too many fines can accelerate jaw plate wear. What happens is the fines will fill the jaw plate corrugations or valleys. These valleys are necessary for the crusher to crush efficiently. Filling the valleys with fines creates an event called compaction. Normally a jaw crusher will squeeze the material between the stationary and moving jaw plates. The peaks and valleys of the jaw plates are offset from one another and use the mechanical advantage of leverage to break the rock. Without this the crusher has to rely on energy and friction to crush the rock. Compaction will also impose increased loads to the crusher as much as five times the normal crushing force. To the opposite,feed material that is too large also affects wear life. A jaw crusher in most applications is a 6 to 1 ratio of feed reduction. Exceeding the reduction ratio can create crushing forces that can exceed the crushers design limits and will affect your overall production and machine performance. With the over-sized feed material you will have a tendency to scrub the material until the jaw plate can get a bite on it. This will also accelerate wear.

If you are using dust suppression it to can also be a factor. Water is actually very abrasive and will accelerate plate wear. If you are using dust suppression you should keep in mind that the dust is better controlled by using a fine spray as appose to using a stream of water. Match the water to the dust and you will control more dust and use less water. Also more dust is present at the discharge than the inlet so water nozzle placement is very crucial to controlling dust without causing accelerated wear.

Like several have mentioned already buying quality is very important. Your supplier should be able to tell you what metal composition your jaw plate is made off. Getting the "right tool for the job" in regards to a good quality jaw plate will give the best performance and longevity.

I wish you the best of luck.

Alan Carter
2 years ago
Alan Carter 2 years ago

Bill is absolutely spot on with his analysis and advice. Compaction is often the main cause for excessive unnecessary wear to the jaw plates.

He is also right about the feed reduction ratio of 6-1. This has been proven worldwide in most applications. In the case of a cone crusher the ration is closer to 8-1. Exceeding the crusher design limits is a common problem, and does not just affect wear on the plates, but the entire hydraulic system too, thus causing other severe issues to your machine.

I agree as well that the dust suppression should be with light spray nozzles and not a stream of water. Water also slows down the further process of screening.
The only case where I have seen the benefit of adding water to material is before entering a VSI tertiary crusher, as this adds weight to the stone. Only if the stone is light and porous in weight, though it may still be abrasive... such as volcanic rock.

Maya Rothman
2 years ago
Maya Rothman 2 years ago

Would a flatter jaw profile instead of the "corrugation" type, combined with a higher Mn/Cr % reduce compaction in plants where a grizzly type of pre screening is not a viable option?

Bill Fraser
2 years ago
Bill Fraser 2 years ago

There are different types of jaw plates available that can have different depths and pitches to the corrugation. A jaw plate without corrugation will create a compaction event. You need corrugation but you can get a straight to a full belly style plate to help with your specific application. If this is what you meant by the profile then yes it could have an effect on jaw performance. There are also what they call "filled in end jaw dies" but should only be used for specific applications and only after consulting the crusher manufacture. And then it is only used on the stationary side as a rule. What I would recommend is talking to your crusher manufacture for specifics related to the types of plates available for your crusher. As with my company and others we have a teams of application specialist that would be happy to help and could offer a recommendation that could best fit your applications needs and help your crusher performance.

Bob Mathias
2 years ago
Bob Mathias 2 years ago

If usually your customer use Mn 18% with Cr 2%.The Materials work index that we crushed is 28, can you comment if we use a Jaw Plate with Mn 18 % with Cr 2% can reach a 500 hrs ?, last replacement of our Jaw Plate its only 150 hrs. this is our battle neck . As also mention in a comment about the different types of Jaw Plates, I think we have to find the correct design with this kind of materials we crush. We are in a river quarry, materials are mix .

John Koenig
2 years ago
John Koenig 2 years ago

The issues are very well summarized: including about the deleterious effects of fines and water on jaw life. Low-strength abrasive materials can cause standard manganese to wear surprisingly fast, as the wearing surface does not work-harden. With very abrasive materials, special 21-23% Mn alloys can help.

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