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Galv

22 Feb The Galvanizing Process

Hot dip galvanizing is the process of coating iron or steel with a layer of zinc by immersing the metal in a bath of molten zinc at a temperature of around 842°F (450 °C). During the process, a metallurgically bonded coating is formed which protects the steel from harsh environments, whether they be external or internal.

Galvanized steel is widely used in applications where corrosion resistance is needed without the cost of stainless steel and can be identified by the crystallised pattern on the surface (often called a ‘spangle’). Galvanizing is probably the most environmentally friendly process available to prevent corrosion.

hot-dip-galvansing-processThe galvanizing reaction will only occur on a chemically clean surface. In common with most zinc coating processes, the secret to achieving a good quality coating lies in the preparation of the surface. It is essential that this is free of grease, dirt and scale before galvanizing. These types of contamination are removed by a variety of processes and common practice is to degrease first using an alkaline or acidic solution into which the component is dipped. The article is then rinsed in cold water to avoid contaminating the rest of the process. The article is then dipped in hydrochloric acid at ambient temperature to remove rust or mill scale. Welding slag, paint and heavy grease will not be removed by these cleaning steps and should be removed by the fabricator before the work is sent to the galvanizers. After further rinsing, the components will then commonly undergo a fluxing procedure.

This is normally applied by dipping in a flux solution – usually about 30% zinc ammonium chloride at around 65-80°C. Alternatively, some galvanizing plants may operate using a flux blanket on top of the galvanizing bath. The fluxing operation removes the last traces of oxide from the surface and allows the molten zinc to wet the steel.

Post Treatment

Post galvanizing treatment can include quenching into water or air cooling. Conditions in the galvanizing plat such as temperature, humidity and air quality do not affect the quality of the galvanizing coating.

By contrast, these are critically important for good quality painting. No post treatment of galvanized articles is necessary and a paint or a powder coating may be applied for enhanced aesthetics or for additional protection where the environment is extremely aggressive. Chemical conversion coatings and other barrier systems may be applied to minimise the occurrence of wet storage stain.

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08 Feb The Difference between Steel and Stainless Steel

All steel is made from iron mixed with carbon. Sheet metal, or sheet steel, is simply mild steel that is pressed out from ingots through a roller several time to achieve the desired sheet thickness (hot rolled and annealed). The higher the level of carbon, the stronger it becomes and the most difficult it is to work with processes such as cutting.info-compare-stainless-nickel-aluminum-switchplates

Stainless Steel has additional elements added to suit different purposes but a minimum of 10.5% chromium. This creates a chromium oxide film on the surface, which prevents oxygen from permeating and causing rust, thus giving stainless steel its superior anti corrosion qualities.

There are around 150 different types of stainless steel but the most common is Type 304 or food quality stainless steel, typically used in things like drinking water tanks. It is made from 18% chromium and 8% nickel. However, stainless steel water tanks on a yacht are more likely to be made from Type 316. This contains 16% chromium, 10% nickel and 2% molybdenum, which adds additional protection from chlorides found in salt water and dicing compounds.

Stainless steel is more expensive than mild steel sheet and therefore it would normally be chosen only for a specific purpose based on the qualities of that particular type on stainless steel.

Fabricating Mild Steel Sheet

This is one of the most versatile of all metals and found in anything from car panels to trailers. Depending on its hardness, it can be worked using a variety of relatively basic tools and techniques, from shears to drills, and lends itself well to welding. Anti-corrosion qualities can be added through galvanising or through hot zinc spraying.

Fabricating Stainless Steel

Although stainless steel does also come in sheet form (from which flat surface objects like butchers’ blocks are fabricated) it is more commonly pre-formed into more complex shapes that are then fabricated to create a finished product. They are further classified by their crystalline structure of which there are four main categories: austenitic, ferritic, martensitic and duplex. Work hardening stainless steel is the process of cold rolling it to produce ever lighter thickness (gauge), which hardens the material.

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25 Jan How Long Is The Process To Make A Steel Building?

Tarrant GunvilleThere are a lot of factors that can cause issue or delay when it comes to the design and delivery of a steel building. Such factors from redesigns to building complications and even some that may be out of human control can all impact the duration of the delivery. Below are a few common variables that can impact the timeline for constructing a steel building.

Design

When it comes to the design phase, the accuracy of the sketch is what mainly impacts the time it will take to get these drawings engineered created and approved. With engineering drawings, it’s all about the details. The better and clearer the details are the faster these drawings will come together which will speed up the construction process.

Production

Once the drawings have been approved and are ready to go, its time to get the materials together. When it comes to the materials, this can be a tricky process. Materials that are in stock will reduce the fabrication time, while custom materials will take longer to obtain. When dealing with fabrication, it’s all on a case by case basis. The more complex a building the longer the fabrication may take. Shipping materials can also tack on some time. With shipping items, factors such as weather, distance and road conditions can make the construction process lengthier.

Construction

It’s no secret that construction schedules tend to go off course from time to time. Its totally normal for construction to be delayed due to weather conditions, equipment delivery delays and more. It’s important to also note that building size plays a large role in the duration of the project as well. Simple standard buildings typically take less time to complete rather than their complex counterparts.

Here at Rowtec, we try our very best to avoid construction delays. We take extra care in the design and planning of delivery to provide our best chances at the project running smoothly.

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11 Jan Wrought Iron VS Cast Iron

People often assume that cast iron and wrought iron are interchangeable terms for early iron work, but there is  world of difference. Wrought IronIron Gates is iron that has been heated and then worked with tools. Cast Iron is iron that has been melted, poured into a mould, and allowed to solidify.

The fundamental distinction between cast iron and wrought iron is in how they are produced. The differences can be found in the names: wrought is a past participle of work (“worked iron”), and cast describes anything formed by the casting process. The different methods of production create metals with varying strengths and weaknesses, which is why you rarely see a cast iron fence or a wrought iron frying pan.

Wrought iron is composed primarily of elemental iron with small amounts (1-2 percent) of added slag (the by-product of iron ore smelting, consisting of a mixture of silicon, sulphur, phosphorous, and aluminium oxides). Wrought iron is made by repeatedly heating the material and working it with tools to deform it.

Wrought iron is highly malleable, allowing it to be heated, and re-heated, and worked into various shapes – wrought iron grows stronger the more it’s worked and is characterized by its fibrous appearance. Wrought iron contains less carbon than cast iron, making it softer and more ductile. It is also highly resistant to fatigue; if large amounts of pressure are applied, it will undergo a large amount of deformation before failing.

The term “wrought iron” is often misused today; it is commonly used to describe designs similar to historical wrought iron pieces – regardless of the metal used. Mild steel that has been machine-bent into shape in a cold state or cast steel and iron pieces that have been painted black both regularly mislabelled as wrought iron work. To be truly designated as wrought iron, however, a metal piece must be forged by a blacksmith who heats it and hammers it into shape.

Cast iron can refer to a range of iron alloys, but it Is most commonly associated with grey iron. Despite having the name iron, it isn’t pure elemental iron (Fe on the periodic table) – its actually an alloy containing 2-4% carbon, plus small amounts of silicon and manganese. Other impurities, such as sulphur and phosphorus, are also common.

Cast iron is formed by smelting iron ore, or melting pig iron (an intermediate product of iron ore extraction), and mixing it with scrap metals and other alloys. The liquid mixture is then poured into moulds and allowed to cool and solidify.

The final result is strong but brittle. Due to the higher carbon, cast iron solidifies as a heterogeneous alloy, meaning it contains multiple constituents, or materials in different phases, within its microstructure.

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evergreen tree

13 Dec How Does The Weather Impact Structural Steel?

 

evergreen treeWhen metal and water combine, it usually results in rust, which is what many people might worry about when they th

ink about their steel structure in the rain. At Rowtec we are here to ease your stress. An engineered metal building from Rowtec is made of high-quality materials, so you don’t have to worry about little things like rust. In this post we will discuss little things you can do to help your metal building survive this ever-changing English weather.

Rain and an Engineered Metal Building

Much like your home, the best way to protect your engineered metal building from rain is to add gutters to your steel building. By adding gutters, you divert the water away from the building and you don’t have to worry about unnecessary leaks or rust.

Lightning and Other Storm Related Weather

Everyone is familiar with the dangers of being outside during a lightning storm: the biggest warning being that lighting is attracted to metal. So why would anyone want a metal building during a storm then, right? Actually, when struck by lightning, an engineered metal building is designed to disperse the heat and electricity from the strike into the ground. This means that you, your family, and anything else inside the steel building will be safe from harm!

If you are wondering whether a steel building could survive more extreme weather conditions, such as hurricanes, the simple answer is yes. Engineered metal buildings that have been built correctly can withstand great forces of wind and don’t bend under pressure.

Snow

If you live in a climate that gets a lot of snow, there are a few things you should consider when it comes to your engineered metal building. Luckily for you, snow damage is easy to prevent. When you are designing your steel structure or reviewing the options to buy, you want to keep in mind that simple roof structures will be beneficial during the winter months. A complex roof design might collect snow in unwanted areas until the sun can do its job and melt it. This could lead to rust which is something you definitely don’t want.

Another suggestion is to plant a few evergreen trees on the windy side of your building. Evergreens blossom all year round and by planting them on the windy side of your steel building, you are creating a natural barrier against those harsh winter winds. Plus, planting trees is good for the environment so it’s a win-win!

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New Technology

16 Nov New Imaging Technology for UK Steel Industry

A researcher from the University of Bath has been awarded a new grant to develop an innovative way of assessing a key stage of the production of steel, greatly benefiting the competitiveness of the UK and EU Steel industry.

The shell-thick project will develop an innovative induction tomography system for assessing the solidification process of metal. This new system will significantly improve the continuous casting process of steel by providing a real-time, non-destructive and reliable method of measuring the molten steel to detect any defects or fails as it solidifies and becomes a market product.

The system will form a kind of contactless bracelet around the billet of molten steel and take continuous measurements as the steel solidifies. It will visualise the electrical conductivity of the different states of the solidifying steel and therefore provide an image of the structural composition of the steel as it cools. By enabling industry to continuously monitor and alter the cooling process of steel, this innovative method will improve the quality, safety, productivity, costs and ultimately competitiveness of the UK and EU steel industries.

Induction tomography Is a new and emerging non-invasive imaging technique used in a number of applications including medical diagnostics, geophysical exploration and civil engineering. The EU and particularly UK steel industry is currently in a desperate state and facing widespread job losses due to its inability to compete with the highly subsidised steel industries in China. Steelworks such as the Tata steelworks at Port Talbot are currently in emergency talks to try and prevent the plant closing. It is hoped this technology may help the UK/EU steel industry become more competitive and have greater job security in the long-term future.

The university of Bath works closely with its industrial partners in the UK and across the EU to being innovation to the marketplace, delivering impactful research to industry and society. Dr Manush Soleimanifrom the University of Bath’s Department of Electronic & Electrical Engineering has received an EU Horizon 2020 grant to lead this three-year project and will work with colleagues at the Fundación Tecnalia Research & Innovation in Spain as well as Italian steel industry companies Ferriere Nord and Ergolines Lab.

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02 Nov Weld Fume Hazards and How to Protect Yourself

Welding fuses two metal pieces together melting the base metal and a filler material forming a joint that is often stronger than the base metal. The heating of the base metal and filler causes vapours to emanate from the arc concentrating into extremely fine particles that can be exceedingly bad for human health. We have summarised some of the best practices for protecting yourself and others around you from the dangeweldfume_600xrs of the welding fumes.

What is in Welding Fumes?

Welding fumes occur when a metals temperature is elevated above its boiling point. When this occurs, the metals vapours concentrate into solid particulates that are a combination of the metal being welded and the electrode. The resulting fumes are an intricate combination of silicates, fluorides and metallic oxides. The composition of welding fumes can differ depending on the type of metal and flux being used:

  • Welding stainless steel produces lower amount of iron and a greater amount of nickel or hexavalent chromium.
  • Mild steel welding fumes consists of mainly iron and trace amounts of metal additives like copper, titanium, cobalt, molybdenum, vanadium, hex chromium, manganese and nickel.
  • Nickel alloys contains very scarce amounts of iron and has much more nickel.
  • Fluxes made from fluoride or silica generates fluoride fumes, metallic silicates and amorphous silica.

Protect Yourself from Welding Fumes!

  • Coatings– The safest practice with coated steel is to remove the coating completely before welding so as to prevent the coating from becoming toxic vapours from the heat of the arc. This can usually be performed with an angle grinder and flap wheel.
  • Welding Outdoors– Welders working outdoors should always position themselves so that they are working upwind of the arc so that the majority of the weld fumes will travel away from them.
  • Welding Indoors– When proper natural ventilation is not possible local exhaust ventilation systems should be used to help clear the welders breathing from gases and fumes. To be sure that the greatest number of fumes possible are being removed when using a local exhaust ventilation system make sure to keep the extractor guns and vacuum nozzles as close to the plume source as possible. Also, flexible exhaust systems can be used to draw the fumes away from the welder but always be sure that the ventilation is also aimed away from other workers as well.
  • Confined Spaces– When welding in confined spaces always use sufficient mechanical ventilation or airline respirators and make sure to avoid blockage of ventilation equipment.
  • Respiratory Mask– Always be sure to wear respiratory protection if ventilation cannot reduce fume exposures to safe levels.
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Powder Coating

19 Oct The Powder Coating Process

Powder coating is used very widely to impact a long lasting, durable and anti-corrosive coating to a wide variety of objects including architectural steel parts, such as railings. It is preferred and specified by many designers because of its attractive finish and wide range of available colours.powder-coating-prices-australia

The most common type consists of a pulverised mix of epoxy resin and plastic polymers with particles anywhere from 5 to about 50 microns thick. When heated to around 150°C, the compound melts and the constituent parts fuse to form solid protective coating over the surface of the object. Because of the way it can be formulated, there are many types of powder and a very wide range of colours.

Once the object to be treated has been completely cleaned of all contaminants (often by shot blasting or soda blasting) it is electrically grounded. The powder is then sprayed on using compressed air and a spray gun that imparts an electrostatic charge to the powder. This causes it to adhere evenly across the surface of the object. The object is then heat cured in an oven or by using infra-red heat in situ. While the compound melts the flows to form a liquid coating at about 150°Cit needs to be cured at 200°C. The duration required for the cure varies from about 10 to 20 minutes depending on the formulation and characteristics of the powder.

Most any metal object can be powder coated, from domestic items to handrails in shopping malls. Two characteristics are mandatory in suitable subjects:

  • Must be capable of holding an electrostatic charge, which is critical for the powder to stick.
  • Must withstand the heat of the curing process without sustaining damage

Typical examples of suitable materials include those made from steel and steel alloys such as mild, galvanised and stainless steel as well as others such as aluminium.

Advantages

  • Powder coating is an environmentally friendly process, with no fumes or odours during the spraying process.
  • Powder coated surfaces are far more resistant to chipping or cracking than conventional paint because of the inherent elasticity of the compound.
  • It is a fast process – an item can be prepared, sprayed, cured and ready with an hour.

Disadvantages

  • Powder coating is commonly applicable only to metal items and only those that can withstand the heat of the curing oven without suffering damage. Ultra violet curing with special powders can be performed on plastic but this is a highly specialised branch.
  • After spraying, the powder adheres to the object through electrostatic attraction only and therefore it is easily dislodged if moved or while being placed inside the curing oven, for example.
  • It is not a process suitable for performing on-site and really needs an engineering shop environment for professional work.
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Tarrant Gunville 3

05 Oct Structural Steel or Reinforced Concrete?

Tarrant Gunville 3One of the early decisions that needs to be taken for any structural frame is the use of steel or reinforced concrete. This has long-term effect on the project, including cost and durability. Your choice has an overall impact on different aspects of building design, and its performance. Many businesses comparing structural steel to reinforced concrete find that steel is a more cost-effective solution compared to concrete. But cost isn’t the only factor you should consider when working on construction or civil engineering projects.

When it comes to cost then structural steel has a slight edge over reinforced concrete. Structural steelwork represents only 20% of overall steelwork used in construction, and this is the main reason why steelwork is much cheaper compared to reinforced concrete. The price of construction material has grown overall but the impact of this growth is more on concrete (by mass) than steel.

In terms of construction timing, concrete has a slight edge. It is said that building with concrete can be double the speed compared to a steel structure. But there are different views in support of structural steel as well. Many businesses prefer working with steel due to its versatility, strength and ease of construction.

 

Here is a summary of the comparative advantages and disadvantages of structural steel and reinforced concrete:

Reinforced Concrete Pros & Cons

Pros

  • Better fire-proof quality than steel, wood or brick.
  • Can take any shape with the right moulding.
  • Cost effective construction materials when it comes to certain structures like dams, footings, and piers.

Cons

  • Comparatively expensive.
  • When compared to steel it has low compressive strength.
  • Requires mixing, casting and curing. This might result in a change in the final strength of the concrete.

 

Structural Steel Pros & Cons

Pros

  • Cost effective in terms of materials and labour.
  • They are considered as the future of construction, with many innovations improving the quality and versatility of steel year on year.
  • Useful for construction of offices and commercial buildings.
  • Easily available at competitive prices.
  • Space can be optimised.

Cons

  • Not all builders are used to this material and it requires special tools to operate.
  • Structural steel components are prone to fire damage compared to concrete.
  • During winter the steel structures get cold easily and this might affect people working or living inside it. (This negative can be counteracted with the appropriate coatings and insulation.
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28 Sep Structural Steel Fabrication and Construction

The construction sector has advanced and with it, many new and improved methods including the use of structural steel. Nearly everything in construction consists of structural steel with skyscrapers, large warehouses and shopping malls springing to mind. In fact, steel framed structures are commonly used across a wide range of construction projects including garages, residential housing and short-term temporary structures and for good reason.

Steel fabrication is used to create various components and products with different qualities for numerous applications. Structural steelwork has been the primary choice for most builders, engineers, contractors and structural steel fabricators. Many industries rely on steel products and fabrication services due its quality, reliability, flexibility, cost effectiveness and sustainability.

Steel Framed Building | Dorset

Durability and Versatility of Structural Steel

Structural steel ductile which means it has the ability to withstand stress for long periods of time and bend without breaking. Steel can be moulded into virtually any shape and needs little maintenance. It’s also reusable and easily recyclable without affecting its properties making it a great eco-friendly option. Standing tall against strong winds and extreme weather conditions make structural steel buildings a sure winner.

Structural steel frameworks are made with exact precision ensuring the highest standards and safer building practices. The durability of steel needs no introduction as these benefits clearly indicate:

o  Resistant to adverse weather and remains rust-free

o  Strong underwater and does not shrink

 Fire resistant through the application of intumescent retardants

 Can apply corrosion and weathering resistant material during steel framework fabrication instead of on-site

 Unaffected by termites and insects

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