How Does brass clad steel Work?

Full Transcript:

What&#;s up guys? Michael with Michael Talks Metal back for episode 147! Today we&#;re going to introduce you to clad metals.  You may not know it but there are clad metals around us every day.  Lets define clad as where two or more alloys are bonded together to provide improved performance at reduced cost. We want to take advantage of the properties each component metal contributes to the combination in a cost effective way.

If you want to learn more, please visit our website KLS.

One example is almost any coin in your pocket or purse.  All current US coins except the nickel are clad.  Or for those of you that only pay by way of electrons, check in some desk drawer or jar for a stash of coins.

{insert finding coin and show layers at edge}

Here the issue is cost of manufacture. Coins have intricately detailed engraved portraiture and need to have a long lifetime. Core material used is zinc for the Penny with copper clad. Dimes, Quarters, and Half Dollars are made with a copper core and a nickel alloy clad.

Even using a lower cost core, a penny costs more than twice its face value to produce at the mint.

Another example is found in the kitchen where stainless steel clad pots and pans are considered premium products.  Everyone likes the shiny appearance and cleanliness. But stainless steels do not conduct heat well, so a core of aluminum or copper improves the uniformity of temperature across the pan while the stainless steel surface offers corrosion resistance and does not react with foods. Bingo,we have the best of two worlds.

{ Insert stainless pot}

The most common commercial method for making a clad of two metals ( or more ) is done by hot or cold rolling the metals together. The roll pressure squeezing the two very surfaces together creates the bond. Details are dependent on the specifics of the materials being bonded together.

Many high strength aluminum sheet alloys are clad to provide corrosion or stress corrosion protection for the core alloy.

In another method&#;&#; called explosion cladding or explosion welding does the job of bonding.  Typically two plates have thoroughly prepared mating surfaces and are driven together by a progressive explosion that creates extremely high pressures.

Layers of compatible alloys can be applied by either depositing weld metal or using metal powders plasma spray welded to the core material.

If this has piqued your interest in how any of this is done there are several videos available on You Tube to go to&#;.

If you want to learn more, please visit our website brass clad steel.

Clad metals can be found in many automotive, defense, and aerospace applications and as you might suspect are subject to stringent specifications and part requirements

So CHECK THE SPECS!!!!!!    TWICE

So this is Michael with Michael Talks Metal. Thanks for watching. Need more info on metals, clad an all? Check the website www.michlinmetals.com for more info. Still here and haven&#;t subscribed? Click here. Missed last weeks video, click here. Thanks again for watching. This is Michael with Michael Talks Metal, I will see you next week, same time, same place. 10am YT! I&#;m out!

Cladding is the bonding together of dissimilar metals. It is different from fusion welding or gluing as a method to fasten the metals together. Cladding is often achieved by extruding two metals through a die as well as pressing or rolling sheets together under high pressure.

The United States Mint uses cladding to manufacture coins from different metals. This allows a cheaper metal to be used as a filler. For example, dimes and quarters struck since have cores made from pure copper, with a clad layer consisting of 75% copper and 25% nickel added during production. Half dollars struck from to for circulation and in for collectors also incorporated cladding, albeit in the case of those coins, the core was a mixture of 20.9% silver and 79.1% copper, and its clad layer was 80% silver and 20% copper. Half dollars struck since are produced identically to the dimes and quarters.

Laser cladding is an additive manufacturing approach for metal coatings or precise piece restorations by using high power multi-mode optical fiber laser.[1]

Roll bonding

In roll bonding, two or more layers of different metals are thoroughly cleaned and passed through a pair of rollers under sufficient pressure to bond the layers. The pressure is high enough to deform the metals and reduce the combined thickness of the clad material. Heat may be applied, especially when metals are not ductile enough. As an example of application, bonding of the sheets can be controlled by painting a pattern on one sheet; only the bare metal surfaces bond, and the un-bonded portion can be inflated if the sheet is heated and the coating vaporizes. This is used to make heat exchangers for refrigeration equipment.[2]

Explosive welding

In explosive welding, the pressure to bond the two layers is provided by detonation of a sheet of chemical explosive. No heat-affected zone is produced in the bond between metals. The explosion propagates across the sheet, which tends to expel impurities and oxides from between the sheets. Pieces up to 4 x 16 metres can be manufactured. The process is useful for cladding metal sheets with a corrosion-resistant layer.[2]

Laser cladding

Laser cladding[3][4] is a method of depositing material by which a powdered or wire feedstock material is melted and consolidated by use of a laser in order to coat part of a substrate or fabricate a near-net shape part (additive manufacturing technology).

It is often used to improve mechanical properties or increase corrosion resistance, repair worn out parts,[5][6] and fabricate metal matrix composites.[7] Surface material may be laser cladded directly onto a highly stressed component, i.e. to make a self-lubricating surface. However, such a modification requires further industrialization of the cladding process to adapt it for efficient mass production. Further research on the detailed effects from surface topography, material composition of the laser cladded material and the composition of the additive package in the lubricants on the tribological properties and performance are preferably studied with tribometric testing.

Process

A laser is used to melt metallic powder dropped on a substrate to be coated. The melted metal forms a pool on the substrate; moving the substrate allows the melt pool to solidify in a track of solid metal. Some processes involve moving the laser and powder nozzle assembly over a stationary substrate to produce solidified tracks. The motion of the substrate is guided by a CAM system which interpolates solid objects into a set of tracks, thus producing the desired part at the end of the trajectory.

Automatic laser cladding machines are the subject of ongoing research and development. Many of the process parameters must be manually set, such as laser power, laser focal point, substrate velocity, powder injection rate, etc., and thus require the attention of a specialized technician to ensure proper results. By use of sensors to monitor the deposited track height and width, metallurgical properties, and temperature, constant observation from a technician is no longer required to produce a final product. Further research has been directed to forward processing where system parameters are developed around specific metallurgical properties for user defined applications (such as microstructure, internal stresses, dilution zone gradients, and clad contact angle).

For more information, please visit titanium sheet.

Advantages

• Best technique for coating any shape => increase lifetime of wearing parts.
• Particular dispositions for repairing parts (ideal if the mould of the part no longer exist or too much time is needed for a new fabrication).
• Most suitable technique for graded material application.
• Well adapted for near-net-shape manufacturing.
• Low dilution between track and substrate (unlike other welding processes and strong metallurgical bond.
• Low deformation of the substrate and small heat affected zone (HAZ).
• High cooling rate => fine microstructure.
• A lot of material flexibility (metal, ceramic, even polymer).
• Built part is free of crack and porosity.
• Compact technology.

See also

• Additive manufacturing
• All-Clad
• Copper-clad aluminum wire
• Copper-clad steel
• Goldbeating

References