Clad metals were developed in the early s and one of the first to be used was nickel bonded to carbon steel. This composite was used in the construction of tank cars. Other products made of clad steels are heat exchangers, tanks, processing vessels, materials-handling equipment, storage equipment, etc.
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Clad or composites can be made by several different welding manufacturing methods. The most widely used process is roll welding which employs heat and roll pressure to weld the clad to the backing steel. Explosive welding is also used and weld surfacing or overlay is another method of producing a composite material.
Clad steels can have as the cladding material chromium steel in the 12-15% range, stainless steels primarily of the 18/8 and 25/12 analysis, nickel base alloys such as Monel and Inconel, copper-nickel, and copper. The backing material is usually high-quality steel of the ASTM-A285, A212, or similar grade. The tensile strength of clad material depends on the tensile strength of its components and their ratio to its thickness. The clad thickness is uniform throughout the cross section, and the weld between the two metals is continuous throughout.
A slightly different procedure is used for oxygen cutting of clad steel. All of the clad metals mentioned above can be oxygen flame cut with the exception of the copper-clad composite material. The normal limit of clad plate cutting is when the clad material does not exceed 30% of the total thickness. However, higher percentage of cladding may be cut in thicknesses of 12 mm and over. The oxygen pressure is lower when cutting clad steel; however, larger cutting tips are used.
The quality of the cut is very similar to the quality of the cut of carbon steel. When flame cutting clad material the cladding material must be on the underside so that the flame will first cut the carbon steel. The addition of iron powder to the flame will assist the cutting operation.
Schedules of flame cutting are provided by clad steel producers as well as flame-cutting equipment producers. For oxygen flame cutting copper and copper-nickel clad steels the copper clad surface must be removed and the backing steel cut in the same fashion as bare carbon steel.
Copper and brass clad plate can be cut using iron powder cutting. Clad steels can be fabricated by bending and rolling, shearing, punching, and machining in the same manner as the equivalent carbon steels. Clad materials can be preheated and given stress relief heat treatment in the same manner as carbon steels. However, stress relieving temperatures should be verified by consulting with the manufacturer of the clad material.
Clad materials can be successfully welded by adopting special joint details and following specific welding procedures. Special joint details and welding procedures are established in order to maintain uniform characteristic of the clad material. Inasmuch as the clad material is utilized to provide special properties it is important that the weld joint retain these same properties. It is also important that the structural strength of the joint be obtained with the quality welds of the backing metal.
The normal procedure for making a butt joint in clad plate is to weld the backing or steel side first with a welding procedure suitable for the carbon steel base material being welded. Then the clad side is welded with the suitable procedure for the material being joined. This sequence is preferable in order to avoid the possibility of producing hard brittle deposits, which might occur if carbon steel weld metal is deposited on the clad material.
Different joint preparations can be used to avoid the possible pickup of carbon steel in the clad alloy weld. Any weld joint made on clad material should be a full-penetration joint. When designing the joint details it is wise to make the root of the weld the clad side of the composite plate. This may not always be possible; however, it is more economical since most of the weld metal can be of the less expensive carbon steel rather than the expensive alloy clad metal.
The selection of the welding process or processes to be used would be based on that normally used for welding the material in question in the thickness and position required. Shielded metal arc welding is probably used more often; however, submerged arc welding is used for fabricating large thick vessels and the gas metal arc welding process is used for medium thicknesses; the flux-cored arc welding process is used for the steel side, and gas tungsten arc welding is sometimes used for the thinner materials, particularly the clad side.
The selection of process should be based on all factors normally considered. It is important to select a process that will avoid penetrating from one material into the other. The welding procedure should be designed so that the clad side is joined using the appropriate process and filler metal to be used with the clad metal and the backing side should be welded with the appropriate process and filler metal recommended for the backing metal. For code work the welding procedure must be qualified in accordance with the specification requirements.
The normal procedure, assuming that the material is properly prepared and fitted is as follows. The backing side or steel side would be welded first. The depth of penetration of the root pass must be closely controlled by selecting the proper procedure and filler metal. It is desirable to produce a root pass which will penetrate through the root of the backing metal weld joint into the root face area yet not come in contact with the clad metal.
A low-hydrogen deposit is recommended. If penetration is excessive and the root bead melts into the clad material because of poor fitup or any other reason the deposit will be brittle. If this occurs the weld will have to be removed and remade. However, if the penetration of the backing steel root bead is insufficient the amount of back gouging will be excessive and larger amounts of the clad material weld metal will be required. The steel side of the joint should be welded at least half way prior to making any of the weld on the clad side. If warpage is not a factor, the steel side weld can be completed before welding is started on the clad side.
The clad side of the joint is prepared by gouging to sound metal or into the root pass made from the backing steel side. This can be done by air carbon arc gouging or by chipping. The gouging should be sufficient to penetrate into the root pass so that a full penetration of the joint will result. This will determine the depth of the gouging operation. It is also a measure of the depth of penetration of the root pass. Grinding is not recommended since it tends to wander from the root of the joint and may also cover up an unfused root by smearing the metal. If the depth of gouging is excessive, weld passes made with the steel electrode may be required to avoid using an excessive amount of clad metal electrode.
On thin materials the gas tungsten arc welding process may be used, on thicker materials the shielded metal arc welding process or the gas metal arc process may be used. The filler metal must be selected to be compatible with the clad metal analysis.
There is always the likelihood of diluting the clad metal deposit by too much penetration into the steel backing metal. Special technique should be used to minimize penetration into the steel backing material. This is done by directing the arc on the molten puddle instead of on the base metal.
When welding copper or copper nickel clad steels a high nickel electrode is recommended for the first pass (ECuNi or ENi-1). The remaining passes of the joint in the clad metal should be welded so that the copper or copper nickel electrode matches the composition of the clad metal.
When the clad metal is stainless steel the initial pass which might fuse into the carbon steel backing should be of a richer analysis of alloying elements than necessary to match the stainless cladding. This same principle is used when the clad material is Inconel or Monel. The remaining portion of the clad side weld should be made with the electrode compatible with or having the same analysis as the clad metal. The procedure should be designed so that the final weld layer will have the same composition as the clad metal.
On heavier thicknesses where the weld of the backing steel is made from both sides it is important to avoid allowing the steel weld metal to come in contact or to fuse with the clad metal. This will cause a contamination of the deposit which may result in a brittle weld.
When welding thinner gauge clad plate and inside clad pipe it may be more economical to make the complete weld using the alloy weld metal compatible with the clad metal instead of using two types of filler metal. The alloy filler metal must be compatible with the steel backing metal. The expense of the welding filler metal may be higher, but the total weld joint may be less expensive because of the more straightforward procedure. Joint preparation may also be less extensive using this procedure.
For medium thickness, the joint preparation is a single vee or bevel without a large root face. The root face is obtained by grinding the feather edge to provide a small root face. If possible the face of the weld will be the steel or backing side of the joint. The backing side or steel side is welded first using the small diameter electrode for the root pass to insure complete penetration.
If the composite is a pipe or if it must be welded from one side, the buttering technique should be used. In this case the filler metal must provide an analysis equal to the clad metal and be compatible with the backing steel. Weld passes are made on the edge of the composite to butter the clad and backing metal. The buttering pass must be smoothed to the design dimensions prior to fitup. The same electrode can be used to make the joint.
When welding heavy, thick composite plate the U groove weld joint design is recommended instead of the vee groove in order to minimize the amount of weld metal. The same principles mentioned previously are used.
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When the submerged arc welding process is used for the steel side of the clad plate caution must be exercised to avoid penetrating into the clad metal. This same caution applies to automatic flux-cored arc welding or gas metal arc welding. A larger root face is required and fitup must be very accurate in order to control root bead penetration.
The submerged arc process can also be used on the clad side when welding stainless alloys. However, caution must be exercised to minimize dilution of a high-alloy material with the carbon steel backing metal. The proper filler metal and flux must be utilized. To minimize admixture of the final pass it is recommended that the clad side be welded with at least two passes so that dilution would be minimized in the final pass.
Special quality control precautions must be established when welding clad metals so that undercut, incomplete penetration, lack of fusion, etc., are not allowed. In addition, special inspection techniques must be incorporated to detect cracks or other defects in the weld joints. This is particularly important with respect to the clad side which may be exposed to a corrosive environment.
Here are some frequently asked questions we get on metal studs. Here at US Frame Factory we are metal stud manufacturers and general contractors who have worked on project ranging from small houses to multi-million dollar hotels and churches. We exclusively work with metal studs and its our area of expertise.
No, all our studs are individually cut to length and charged per foot based on an algorithm. The rate is fixed until you get up to LF of metal studs then it slowly decreases.
We carry small quantities of steel for most profiles and can manufacture the metal in 1-2 days. For larger custom length orders expect 1-2 weeks.
We manufacture metal studs ranging from 1-5/8″ width to 12″ width. Our flange widths are from 1-1/4″ up to 4″ flange height. We can manufacture from 28 gauge to 12 gauge.
Yes, we sell curved track, slotted track, clips, web stiffeners, and more. Contact sales for more information.
No, most 20 gauge studs are not structural. When most people refer to a 20 gauge metal stud they’re typically referring to a “EQ20 gauge stud” or an equivalent 20 gauge stud. The metal is far thinner than an actual 20 gauge stud. This a stud designed to hang drywall on in interior applications. The stud performs like a true 20 gauge in terms of hanging drywall, so when its just under lateral load, but it doesn’t have the same supporting load as a true 20 gauge stud would have. Read about non-structural drywall studs here.
Buildings with large open spans and big wall heights (Churches, Malls, Car Dealerships) structural steel should be used along side metal studs to support these large spans. Ideal buildings for total light-gauges construction are builds with more room partitions like hotels and mutli-family living, usually in the form of mid-rise construction.
When you compare steel framing to other construction materials, it’s not as good at saving energy. Wood, on the other hand, is almost four times better at holding in heat. The reason steel-framed buildings aren’t good at saving energy is because of metal’s thermal bridging. This allows heat to escape from the inside to the steel frame in the walls, mainly through the steel itself.
To fix this thermal bridging issue, we often need to add layers of special insulating boards on the outside of the building. Boards like EPS, XPS, or Polyiso, create a non-conductive thermal barrier.
In the US, this is dictated by building codes. Hospitals, schools, churches, office buildings, and mid-rise construction often have mandatory fire rating and shelter building requirements. Metal studs offer fire resistance, allowing for your walls to have higher fire ratings. Metal stud framing is becoming popular in all US Gulf Coast regions due to high wind resistance as well as the ability to deal with the humid climate.
Sustainable materials provided quickly and efficiently are the way of the future in the building. Faster build times, reduced costs, more versatile design alternatives, and a durable, practical solution to buildings may all be achieved using a Cold-Formed Steel (CFS) platform.
While material price is typically comparable on the front end, there are substantial advantages of using CFS, which results in the whole project being developed at a lower cost. These are speed of set-up, reduced labor, and lower insurance premiums.
Yes, buildings up to five stories tall can be constructed solely from cold-formed steel.
They are used, just not as frequently. Metal studs are less commonly used in residential construction compared to wood studs due to factors like cost, craftsman familiarity, weight, sound transmission, thermal conductivity, and customization. While metal studs offer benefits like fire resistance and durability, wood studs are more cost-effective, lighter, and easier for builders to work with. However, metal studs may be chosen for specific situations, such as regions with strict fire codes or design requirements, or for their durability and termite resistance.
Galvanized steel is resistant to cracking, shrinking, splintering, creeping, splitting, warping, swelling, and rot. Termites and other wood-destroying insects cannot eat steel.
Steel almost always ends up being the pricier when compared with wood. Working with steel also requires more labor, so tradespeople charge more to work with steel compared to timber. This means that, generally, building a home with a steel frame will cost more than using wood, both for the materials and the construction.
Additionally, the significant energy needed in steel production has a harmful impact on the environment. The steel production industry is one of the major contributors to pollution worldwide, and the steel mills leave a carbon footprint at every stage of the steel production process.
Steel has the highest total recycling rate of any industry in the world, at 86 percent, making it an environmentally friendly option for home framing. Steel framing scrap is a valuable resource that should never be thrown away.
Deflection limits for building finishes help prevent damage such as cracking, warping, or misalignment of the finishes attached to structural elements. These limits vary depending on the material and the type of finish. Here are common guidelines for different finishes.
Exterior cladding options for buildings with metal studs are diverse, and the compatibility of the cladding with metal studs depends on various factors such as the type of metal studs, building codes, climate, and design preferences. Here are some common exterior cladding options that can be compatible with metal studs.
It’s crucial to consult local building codes and regulations, as well as the manufacturer’s installation guidelines for both the cladding material and the metal stud system. Proper installation, moisture management, and thermal insulation considerations are essential to ensure the longevity and performance of the exterior cladding system. Additionally, consulting with a structural engineer or architect can help ensure that your chosen cladding is compatible with your specific metal stud framing design.