Clad Wear Plate – “Overlay” Plate; What is it?

The term “wear plate” doesn’t give you much by way of steel specification.
Nor do the terms “Overlay Plate or Clad-Plate”

Wear Plate, Abrasion Resistant (AR) plate, is primarily used in heavy industrial maintenance applications. (Note that “AR” may also refer to As Rolled plate, but that is not the context we are using here). If a job is banging, clanging, screeching, or in any way loud and offensive it most likely is tearing up steel and could use some sort of hardened plate to keep things from breaking and otherwise wearing out too soon. Clad (Overlay) Plate is a Wear Plate product that is basically the combination of two products bonded together and sold as a unit. Properly matched to the application, it may significantly outlast wear plate.

If you just make wear plate really hard, it will most likely be brittle. It may be great to resist all sorts of sliding wear, but any sort of expected or unexpected vibration or impact may crack the plate. Since most applications in heavy industry involve both sliding abrasion and gouging or impact, the trick is to make a wear plate hard with some degree of ductility. The combination of hardness and ductility is called “toughness”. The nature and degree of toughness will vary with each brand of wear plate, with each chemical recipe and with each individual thermal treatment (hardening) process. Keep in mind there is no specific description of alloy content or hardness contained in the terms; wear plate, AR plate, AR400, AR500, etc. Those descriptors mostly mean that the plate is hard. My “go-to phrase” is; “Wear Plate Is Big and Ugly”. Big and ugly things are generally hard to manage. Keep that in mind, it may help you hold on to your fingers and limbs.

Now, some applications are just too mean and ugly for even highly hardened wear plate to handle. For those cases, CLAD-wear plate has been developed. There is not just one type of clad-wear plate. The overlay portion of the plate may be a heavy coating of hard weld, or a very fine diamond hard spray. For the most part, however, it will be brittle (not ductile). The bottom layer may be soft plate (A36), or it may be hardened wear plate. When these two layers are bonded together the top layer resists abrasive wear while the bottom layer holds it together and keeps it from crumbling. There are many fine grades and brands of this type of product available. Properly applied, it definitely solves big ugly maintenance problems.

When you believe you are ready to try something bigger and uglier than plain old hardened wear plate, share as much about your application as you can.

Is the medium being moved dry or wet, large or small, jagged or smooth, soft or hard?
Is it sliding dropping tumbling, or all of the above?
Is there heat involved (constant or intermittent)?
Does the medium drop onto the plate? If so, how far and how heavy is it?
Does the drop continue throughout the entire distance or does it dissipate (tumble and roll)?
(You may blend different types (grades) of clad plate along the length of your line).

The more specifics you are able to share with your vendor, the greater will be the success of matching the clad-plate to your needs. One man’s treasure in clad plate may be another’s garbage. There is that much variance.

 

-Howard Thomas, Dec 17th 2020

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Bending Steel for Novices

Recently, I thought I’d check the internet to see what was posted relative to bending steel. It is a very broad subject, like asking “What is the price of a car?”

Very difficult to answer without lots of clarification, clarification not only relative to the nature of the steel, the hardness, the bend, the bend radius, the equipment, the operator, and so on. Will you be cold bending, or applying heat? Quickly run through the above questions and then give some thought to the tools you might be using you to bend the steel: pliers, hammer, garden tools? You’ll want to add some simple protective gear (for hands, face, head, feet, etc.)

BENDING STEEL IS POTENTIALLY DANGEROUS. I’m not telling you not to attempt bending steel. But, if you’re a novice (beginner), your first consideration should be to have a professional, or experienced individual do it. If that is just not an option, then approach bending any steel with a high degree of caution. Bending even a small thin strip of steel may result in problems, including serious injury.

One foolproof caution a novice should employ before attempting to bend steel is this: Hold the bar of steel close enough to clearly see the surface finish and the sharp edges. Grasp it firmly in both hands and look closely to see if you can determine grain direction. Whack yourself in the forehead. It should hurt, causing you to reconsider what you are considering doing, or at least to insure you exercise extra caution and make use of safety gear such as gloves, safety goggles, helmet, whatever.

BENDING STEEL IS DANGEROUS!  BENDING HARDENED STEEL IS NOT ONLY DANGEROUS; IT IS POTENTIALLY DEADLY. How do you determine if it is soft steel or if it has been hardened?

If you can grip it in both hands and bend it, it’s probably on the softer side. If you feel that it should be bending but it’s not budging, it’s time for some extra caution. It might be a piece of steel that is dead hard. If you hit that with a hammer, or even if you just apply too much force, it may shatter, discharging projectile pieces.

In general, avoid tight radius bends. Slow, minimal curves are safer for you, your neighbors, and the steel. If you do need to make a 90-degree bend, the curve at the point of the bend (bend radius) will have to be large, maybe ever 2” diameter or greater. If that is not going to work for your project, it’s time to consider that your attempted blacksmithing is perhaps ill conceived.

Bending steel at colder temperatures is riskier than bending it at higher temperatures.

Granted, that makes handling it more difficult, but the chances of successful results are increased.

When you anticipate bending steel, whether it is behind the garage at home or in your basement, respect it as a serious material and approach it with the caution it deserves; think danger like you would if you were working with large hungry predatory cats, people prone to projectile vomiting, or high voltage electrical current.

-Howard Thomas, November 6th 2020

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