In the high-temperature world of refractory anchors, there are seven deadly sins that can undermine your projects and lead to costly repercussions. From outdated welding techniques to improper alloy selection, and poor quality anchors to bad installation practices, each sin has its own set of consequences.
In this article, we will delve into each of these transgressions, shedding light on their potential pitfalls and providing innovative solutions to ensure your refractory anchor installations stand the test of time and the demands of modern applications.
Deadly Sin #1 - Using outdated welding technology
Traditional welding techniques, which include hand and stud welding, offer inconsistent and poor-quality welds and are much more time-consuming in the welding process.
In hand welding, if you need a more efficient hand-welded anchor, welders need to have huge expertise and monitor each weld individually, slowing down their operations. In refractory areas, such as in corners, ceilings, and confined spaces, hand welding proves to be difficult due to the distance safety regulations, the accessibility of the machinery and the health risks associated with the toxic fumes.
Stud welding machines have no control over the current except for the input and output in proportion to the settings. There is no mechanism in the machine to stabilize the power. Some of the more common defects include the spread of molten metal, spattering of metal, and cracked weld connections. Many stud welding machines also have hand-welding options included in their machines, this is because welders have to switch to stick welding when the stud welder experiences rejected anchors.
Hand and stud welding technology was innovative once upon a time, but these methods have failed to keep up with modern applications.
The development of the Rapid Arc Welding (RAW) technology has been made possible by understanding these types of problems that exist in the stud and hand welding industry. It has solved many problems that conventional hand –and stud welding have had for a long time. It’s safe, user-friendly, very fast and it delivers welds of high quality. Due to RAW, we are able to provide the customer with a highly cost-effective alternative to the older, more conventional methods of refractory anchor installation.
RAW technology is entirely computer-controlled and it automatically checks the condition of the material at the welding point as well as all welding parameters.
Quality control is very important to us and all our supervisors check the quality of the weld by conducting visual inspections and bend or hammer tests. Furthermore, the RAW machine's RDCA (Remote Data Collection Access) software records all data and creates a real-time graph of the welding conditions.
Deadly Sin #2 – Incorrect alloy selection
In high-temperature settings, refractory anchors play a crucial role in upholding and steadying refractory materials. The longevity and performance of these anchors hinge on the selection of the optimal alloy and should be determined by the precise demands and circumstances of the given application, including the operational temperature, chemical environment, mechanical strain, and other specific criteria.
It is imperative to choose the most fitting alloy to ensure that refractory anchors can endure the rigours they will encounter throughout their service life.
Want to further protect your refractory anchors and extend their lifespan? Adding Bright Solution Annealing (BSA) to your next anchor order may be the smartest thing you do! BSA offers numerous benefits which include lower corrosion rate, lower embrittlement rate and volume, and longer-lasting refractory anchoring systems.
Deadly Sin #3 – Poor quality anchors
Refractory anchors come in all shapes, sizes and materials, it all depends on your specific requirements. And these days, refractory anchor producers and suppliers are a dime a dozen as numerous companies have begun to pop up in recent years. Getting hold of cheap anchors has become easy, but they come at a much higher cost in the long term. Poor quality anchors lead to failures and emergency shutdowns when the refractory material needs to be repaired or replaced which has financial ramifications.
Metal verification is key when it comes to ensuring the quality of your anchors. Positive Material Identification (PMI) is a non-destructive, quick test that measures the composition of the alloy.
Innovation is also important when it comes to ensuring that the anchors that are installed can keep up with the ever-increasing demands that modern applications put on refractory material.
Deadly Sin #4 - Wrong type of anchors
Proper anchor selection is one of the most important aspects to help ensure a successful refractory anchor installation project.
Take burner pipes in the cement industry as an example. A common anchoring method is to use V anchors which are welded directly to the casing or made movable by tack welding through a washer. While this anchor is the most common choice for this specific purpose, time has proven that it is incapable of lasting a complete turnaround. V anchors are seldom able to hold the refractory materials together on the curved outside of units, and are more suitable for use on inner diameters or flat surfaces, either in the horizontal or vertical positions.
The SpeedCell® is purpose-designed to work as a high-performance refractory anchor. Positioned on a threaded stud, the SpeedCell® fixes the cracked refractory to such a degree that the heat cannot find a path to reach the steel liner or damage the anchoring system. Thanks to its shape, the SpeedCell® forms a real composite by design. Unlike a standard V anchor, the SpeedCell® ‘hugs’ the refractory. The refractory material spreads itself through the open pattern of the Cell, cannot be dislodged, and is held in position rigidly. In our experience, burner pipes will last two or three times longer thanks to our SpeedCell® system.
Deadly Sin #5: Effects of alternative fuels on refractory anchors
Many high-temperature industries are transitioning to alternative fuels, which, despite producing lower CO2 emissions upon combustion, contain a significant amount of volatile substances, such as alkalis, sulfur, chlorides, and ash-forming materials. These compounds contribute to an elevated incidence of coating formation, corrosion, and erosion in refractory materials. The introduction of excessive concentrations of alkali salts, sulfates, and chlorides into the kiln system for example detrimentally affects refractory performance, resulting in extensive coating formation on refractory surfaces and premature refractory failure. Consequently, this situation leads to unplanned breakdowns and shutdowns of cement plants.
To mitigate these challenges, it is imperative to employ refractory anchors of superior quality that effectively prevent these chemicals from reacting with and causing corrosion or embrittlement.
Deadly Sin #6 - Wrong refractory
Additional attention needs to be given to the quality of the refractory and the way it is applied. Numerous well-crafted refractory products excel in specific applications but may not suit others. What truly matters is finding the perfect material for your unique application.
Additionally, miscalculations in expansion can lead to early material replacement, causing downtime and increased expenses. It's vital to thoroughly explore your material options, taking into account their suitability for your specific application and expected lifespan.
Exercise caution when dealing with contractors who often have a narrow focus on a single material. Determine your budget and collaborate with a team well-versed in a variety of materials and application methods. This way, you can discover the best solution for your unique needs in a cost-effective manner.
Deadly Sin #7 - Bad installation
As we explored in Deadly Sin #1, installation of refractory anchors can be done with outdated traditional welding techniques, which come with their own problems, or with our innovative RAW technology.
Hand or stud welding gives inconsistent and poor-quality welds, which leads to corrosion or embrittlement and eventually refractory failure. Alternatively, RAW technology solves many of the problems that conventional hand and stud welding have had for a long time. It is safe, user-friendly, very fast, and it delivers high-quality welds.
The sizing and spacing of refractory anchors are also important to take into consideration when planning the installation. The sizing of anchors for a refractory lining is contingent on factors such as refractory thickness. The determination of anchor spacing should be project-specific, taking into account factors like the mechanical properties of the anchors and the refractory lining, which are influenced by the temperature. Refractory engineers leverage these properties within mathematical models to formulate the most effective anchor spacing pattern and strategy for each unique project.
Typically, established technical specifications dictate the relationship between refractory type, lining thickness, anchor height, and installation pattern or spacing. Nevertheless, in light of new technologies like alternative fuels or adjustments to existing designs, it's advisable to revisit and adapt previous specifications to align with your current requirements.
! BONUS Deadly Sin – Dry-out time !
The controlled process of refractory dry-out involves carefully applying heat to the refractory lining to eliminate moisture without harming the materials. It's crucial to engage in comprehensive discussions regarding heat-up procedures, ramp rates, and hold points when transitioning refractory linings from ambient temperatures.
Furthermore, various refractory materials may have distinct dry-out schedules, influencing your overall installation timeline. The composition and curing technology employed also play a pivotal role in determining the refractory's longevity.