Tuesday, October 4, 2022
Nobody wants rusty parts. And nobody is happy when they find previously good parts are suddenly covered in rust.
Rust or corrosion is a significant issue in manufacturing facilities large and small, impacting resources and increasing operating costs. Rust is difficult to prevent and nearly impossible to anticipate on manufactured parts.
When rust occurs, leading manufacturers look to Latem Industries for metal finishing solutions. Here’s how we can help.
What is rust – the short answer?
Rusting is defined as the chemical process in which there is a formation of red or orange coat on the surface of the metals. Rusting is a part of corrosion.
Surface rust can be spotted or flaky and does not protect the underlying iron, which enables the oxide to grow. With enough time, oxygen and moisture will eventually convert an iron part entirely to rust and disintegrate it.
Latem Industries offers various processes to remove rust or corrosion from processed parts. Let’s review some of these options.
Compared to performing rust removal by hand, shot-blasting is significantly faster. It can be very cost effective as well. The rusty part must be free of any moisture or oils before shot blasting, so a pre-wash/dry may be required. Shot blasting will remove rust and many coatings, if required, from metal parts. However, it can damage threads, or delicate surface areas.
Vibratory finishing is ideal for parts and components made of softer metals that would be susceptible to distortion or stresses in a tumbling process. Using a combination of water, media and compounds inside a vibratory bowl, the friction the parts experience removes the rust. Once the process is complete and the rust is gone, special rust inhibitors are added to the vibratory bowl to ensure the parts and components are protected from recurring corrosion. Again, another very cost-effective way to do many parts at once. Part size limitations due to bowl size can be a factor.
Tumble barrel finishing
Barrel tumbling is a mass metal finishing technique that can be used to remove rust. It involves placing rusty pieces into a horizontal barrel, along with compounds and sometimes finishing media, and using centrifugal force to work a clean surface. Excellent process with smaller parts. Media lodging can be a concern.
Ultrasonic rust removal involves placing the rusted pieces into a cavitation bath. Using special rust removal compounds, the rust is removed from the parts. If pitting has occurred due to the rust, this pitting will not be removed in this process. However, the ultrasonic process is excellent for threaded, frail, or delicate parts.
The best process for removing rust from mass quantities of parts is often determined by the extent of the corrosion and the geometry of the part.
Latem Industries Limited offers each of these solutions to our customers. If you are having issues with parts, small or large, contact Latem and let us work our magic!
Thursday, April 8, 2021
What is the difference between shot blasting and shot peening?
Shot blasting is used primarily to improve a surface finish, whether that improvement means removing rust or preparing a part for coating. Shot peening is used primarily to remove residual stresses from a part, therefore strengthening it, and enhancing the shelf life.
Shot blasting or peening Stainless Steel?
Parts can be blasted with glass, ceramic, organic material, plastic and steel media. All the different media’s have their pros and cons. However, if the process or specification requires steel shot to blast or peen the stainless steel, oxidization/rusting will occur afterwards on the stainless steel part.
You would think that stainless steel is exactly that – stainless. What makes stainless steel stainless? In a word, chrome. Stainless steel is an alloy of iron with a minimum of 10.5 percent chromium. Chromium produces a thin layer of oxide on the surface of the steel—the “passive” layer—that prevents surface corrosion. When shot blasting/peening with a steel media, the carbon steel media used embeds contaminants into the stainless steel. Unprotected carbon steel rusts when exposed to air and moisture. This iron oxide film (rust) is “active” and accelerates corrosion by making it easier for more iron oxide to form.
One way to eliminate this issue, is to blast/peen the stainless parts with stainless steel media. By doing this, no contaminants are embedded into the stainless part, and thus, no rusting. However, only stainless steel parts can be blasted in stainless steel media. Should you blast a carbon steel part in stainless steel media, you will contaminate your media, which will in turn contaminate future stainless parts. Stainless steel media is very expensive in comparison to carbon steel media, so most mass finishers do not have machines loaded with stainless steel media, and if they do, the price reflects this as they are limited in the jobs they can run in that machine.
Another method to solve this issue is passivation. In stainless steel, passivation means removing the free iron from the surface of the metal using an acid solution to prevent rust. When the surface iron is removed, the other components of the alloy (primarily chromium, often nickel as well) are left behind as a surface layer over the underlying steel. Upon exposure to air, these elements react with oxygen to form an oxide layer that protects the rest of the steel from corrosion. solutions, bleach or salt (oceanic environments) all will contribute to the need for passivation of the stainless steel.
Call Latem for your stainless steel shot blasting or peening. We are the experts.
Monday, March 23, 2020
Finishing is an essential step in preparing fabricated metal parts and components for assembly and/or sale. The quality of the finish, including the application of protective coatings, will have a monumental impact on the product’s ultimate performance and longevity.
In other words, you need a mass finishing and coating partner you can trust, without fail, every single time.
We are proud to offer key advantages that will not only improve the quality of your products but help you cut costs and streamline your production as well!
1. One-Stop-Shop For Mass Finishing & Mass Coating
Latem Industries offers a full range of mass finishing processes, including parts washing, ultrasonic cleaning, blasting, peening, vibratory finishing, tumbling and sanding. We have close to a dozen vibratory units, multiple barrel tumblers, blasting and peening machines, two drum washers and what is quite possibly the largest commercial ultrasonic cleaning set up in Ontario.
Through our sister company Plastico Industries, we can also offer you numerous mass coating solutions. All our coating processes, including spray nylon and dip nylon coatings, Plastisol coatings, and Polyarmor coatings, are engineered to meet demanding automotive, heavy equipment and military specifications.
2. Smooth Pick Up and Delivery
Our 45,000 sq. ft. mass finishing and coating facility is conveniently located just off Highway 401 in Cambridge, Ontario. You’ve probably spotted our big blue sign on your commute!
Because of this location, we are able to offer shipping at a very competitive rate from the Kitchener area to the Greater Toronto Area.
For help with your trucking needs, call our Logistics Department 519-740-0292 ext. 247.
3. Industry-Leading Staff Expertise
With an ever-changing workload, experienced staff is a must. We invest in our employees through continuous education and training to stay ahead of the curve on all our processes and equipment.
You can count on Latem for a consistent, time-efficient finishing process each and every time.
4. Flexibility On Process and Volume
You’ll benefit from our flexibility in both sides of our businesses! Plastico and Latem Industries run two shifts a day, and many of our employees are cross-trained on a vast array of equipment and processes. This flexibility enables us to offer finishing and coating services for small runs, one-offs and prototypes in addition to mass production.
5. High-Quality Assurance
We have achieved recognition as an ISO 9001:2015 certified metal coater and finisher, demonstrating our commitment to the high level of quality and consistency our customers expect. Our most recent ISO audit was conducted in 2019 by The Registrar Company, a trusted certification body accredited by the ANSI-ANQ National Accreditation Board (ANAB).
See the ISO 9001:2015 Certificate of Registration for Plastico Industries and Latem Industries Ltd.
6. Experience and Technical Capability
Latem and Plastico have been in business for a combined 50+ years, polishing our processes and rounding the burrs that have come up along the way. We have plenty of experience putting out every kind of ‘fire’ that can pop up in mass parts manufacturing: sharp edges, rust, oil...the works!
7. Rapid Processing Time
You’ve got deadlines to meet! Finishing and coating are just two parts of a much bigger picture, and we know you can’t afford any delay.
With our well-trained staff and ample equipment, we’re able to commit to speedy processing times. We’re heavily automotive-based, so we’re well-acquainted with tight turnaround and the need for urgency.
Let our scheduling department impress you with what we can do!
8. Location, Location, Location
Did we mention we’re just minutes off the 401 in Cambridge, Ontario? Latem set up shop here for a reason! Not only are we able to deliver impressive shipping rates throughout the Greater Toronto Area, but we’re located in the heart of Southern Ontario’s manufacturing centre.
Latem Industries is proud to be the premier metal finisher in Southern Ontario.
9. Transparent, Competitive Pricing
To put it simply, we wouldn’t have stayed in business this long if we weren’t competitive! From closely watching efficiencies to improving processes and cycle times, Latem Industries is committed to offering competitive rates that help keep your production costs in check.
10. Environmentally Aware
Did you know our nylon powder coating is derived from Castor bean oils? Our Aquence coating is also environmentally sustainable, containing no heavy metals and very few volatile organic compounds (VOCs.) We also have an extensive wastewater treatment system that’d make a small city jealous!
Plastico and Latem Industries are committed to sustainability and constantly improving our environmental awareness.
At Latem Industries, we can say with confidence that you can count on us for your coating and finishing needs. You don’t have to take it from us - ask any of the hundreds of North American manufacturers who partnered with us over the years!
Call us at 1-888-664-9998 or reach out online to learn more about our mass coating and mass finishing services in Southern Ontario.
Friday, February 21, 2020
Washing is a crucial step in the process of preparing parts for coating or welding. For many types of parts and components, ultrasonic cleaning is the safest and most effective way to get the job done.
However, since ultrasonic cleaning is just one of many different parts washing methods at your disposal, you’ll want to understand how it works before deciding whether it’s the best solution for you!
Here are our answers to the most frequently asked questions we get about ultrasonic cleaning: how ultrasonic cleaning works, when it’s ideal, and whether it’s really effective compared to the more heavy-duty alternatives.
What Is An Ultrasonic Machine and How Does It Work?
Ultrasonic machines use transducers and electric ultrasonic wave generators to generate high-frequency sound waves.
Typically, the transducers are made from piezoelectric crystals, which change in size when electrical voltage is applied.
These devices effectively convert electrical energy into mechanical/sound wave energy, which radiates through a cleaning tank or ‘tub’ in the ultrasonic machine.
How Does Ultrasonic Cleaning Work?
The high-frequency sound waves generated by the transducers and wave generators are transmitted in a liquid solution of water and solvent base, causing cavitation.
Cavitation is simply the implosion of the solution molecules resulting from the transmission of high-frequency sound (pressure waves) through them. This extremely high pressure variation over a very small area causes a great deal of agitation on the surface of parts submerged in the solution.
The surface agitation or “micro-scrubbing” in an ultrasonic cleaning system is highly uniform throughout the surface (including blind holes and part internals) since the agitation is formed in the solution in which the part is placed. This allows the part or component to be cleaned inside and out, regardless of its geometry!
To break it down step-by-step, the ultrasonic cleaning process goes like this:
Which Parts Are Ideal for Ultrasonic Washing?
Virtually any kind of part or component can benefit from ultrasonic cleaning, but it’s the more fragile or complex parts that were really made for this method.
Unlike vibratory or tumble cleaning, the gentle-but-thorough ultrasonic cleaning process does not force the parts into contact with one another. As a result, there is no change to the parts’ appearance or composition. Tumble cleaning and vibratory cleaning, on the other hand, are both purposely aggressive processes that benefit from the parts making contact with each other and/or the finishing media.
Ultrasonic wash is also ideal for single large components. At Latem Industries, our ultrasonic tanks can accommodate parts up to 4’ long and 2.5’ wide.
Can You Remove Rust With An Ultrasonic Wash?
Latem Industries has a proprietary process that allows for the removal of rust from parts or components using ultrasonic wash. As rust or corrosion can occur on virtually any part, the ultrasonic wash quickly and efficiently removes rust from fragile parts or those with complex geometries.
In fact, ultrasonic cleaning not only removes corrosion, but also completely neutralizes rust, returning the parts to their original, perfect finish!
Need Ultrasonic Cleaning? Talk to Canada’s Mass Finishing Experts!
From large and complex to small and delicate, Latem Industries has a cost-effective cleaning solution for every component. To discover more about ultrasonic wash or receive a no-charge quotation, contact us online or by phone at 1-888-664-9998. We look forward to helping you get the perfect finish!
Friday, February 21, 2020
3D printing, once considered the stuff of science fiction, is finally here! The potential applications of 3D printing are practically endless: from modeling and prototyping to direct production of custom parts.
But there’s an important catch: almost all 3D printed parts require some secondary finishing before the part is ready for its next stage.
The truth is, 3D printing is still in its infancy. It needs some help in order to truly be viable for mass production. And Latem Industries, always looking forward, is here to assist!
3D Print Finishing: Smoothing, Refining and Adjusting
The 3D printing process builds a three-dimensional object from a computer-aided design (CAD) model, usually by successively adding material layer by layer. This is also known as additive manufacturing, in contrast to subtractive manufacturing (CNC machined parts).
These parts are usually manufactured in small batches, in a relatively quick time frame. The parts can range from basic shapes to intricate patterns.
Finishing may be required to:
What’s The Best Way to Finish 3D Printed Parts?
There are multiple methods or techniques that can be used on 3D printed parts. The best method depends on the raw material of the part, the requirement needed and pricing. Latem Industries offers several different processes to finish 3D printed parts.
1. Shot Blasting
Most companies use manual sanding to smooth out the surface of a 3D printed part. However, this is not very time efficient, nor can you sand interior or hard-to-reach areas
Shot blasting is a much quicker, more thorough option that can easily reach difficult areas. In a shot blasting process, the 3D parts are placed in a chamber and blasted with small particles. The particles gradually smooth out the parts’ surfaces and remove rough edges.
Blasting will give you a uniform finish with a matte surface. Blasting also increases adhesion of coatings that may be applied to the 3D part.
2. Shot peening
Similar to blasting (and often done using the same shot blasting machines) shot peening will strengthen the part and help to extend its expected life cycle.
Shot peening removes tensile stress and replaces it with compressive stress, making the surface stronger. Imagine a blacksmith hammering a metal object, i.e shield, sword or horseshoe. This is how peening was performed manually!
In a shot peening process, the 3D printed parts are bombarded with smooth, round shots that act as tiny ball-peen hammers. Gradually, the surface of the parts become stronger and more resistant to cracks or fatigue. We can also use shot peening to give the parts a textured surface.
Latem has machines to do this automatically, shortening process times, which in turn reduces cost.
3. Vibratory Finishing
Vibratory systems allow you to process and polish small or delicate 3D parts singularly or in batches.
In a vibratory finishing process, the 3D printed parts are placed in a large bowl containing abrasive media and cleaning agents. The bowl vibrates to agitate the media while rotating in a circular motion. This gentle motion polishes the parts while smoothing their edges and surfaces.
Depending on the raw material, it is possible to polish your 3D printed components to a very shiny or even mirror-like surface!
Tumbling is ideal for small 3D-printed parts post-processing. In a barrel tumbling process, the 3D printed components are placed in a large barrel that also holds abrasive media and cleaning agents. Multiple parts are run at once, gently rubbing against one another, or other media, resulting in a smooth finish.
The benefits of tumbling include speed, consistency and versatility: depending on your choice of abrasives and media, it can be used to produce a wide range of finishes. The process can take minutes up to hours depending on the product and the finish required.
Mass Finishing 3D Printed Parts
Need to give your 3D printed components a finishing touch? At Latem Industries quality and speed are our priority! Contact us online or call us toll-free at 1-888-664-9998 to find out how we can help you improve the finish of your 3D parts.
Monday, November 4, 2019
Shot blasting is a method of descaling, derusting and deburring unfinished metal components. It is often a necessary step prior to assembly, or finishing touches like painting or coating.
In a previous post, we looked at the difference between two common shot blasting machine configurations: batch finishing and continuous finishing systems. To summarize:
In short, batch finishing is stop-and-go, while a continuous system can keep going on and on for as long as you’re loading new parts. It’s not a competition ‒ both methods have clear advantages in different applications. But when it comes to processing large orders, continuous finishing often has the edge in terms of efficiency.
Today, we’ll take a closer look at two types of continuous finishing systems we use to process thousands of parts a week here at Latem Industries: flat bed roller conveyors and overhead conveyors.
Flat Bed Roller Conveyor
In a flat bed roller conveyor system:
Roller conveyor shot blasting systems are ideal for treating long, flat components prior to welding, cutting and machining operations. Large parts can be effectively descaled, derusted or deburred using a flat bed roller conveyor system. It can also be used to remove paint or for general surface preparation.
At Latem Industries, our roller conveyor can accommodate parts as large as 7 feet wide and up to 30 feet long. Its design allows us to process steel plates, profiles, cast iron and galvanized steel pipes, and rolled steel H-beams and I-beams for structural steel construction.
In an overhead conveyor system:
Unlike flat bed roller machines (which are ideal for flat pieces) overhead conveyors can handle large components with unusual or complex shapes. These systems can be used to remove rust or scale, recondition stamped metal, or prepare components after die casting.
At Latem Industries, our overhead conveyor can accomodate parts weighing anywhere from 10lbs to over 300lbs. We’ve found it ideal for castings, welded constructions, forged and stamped parts, and complicated forms like large springs.
Choosing the Best Mass Finishing Method
When Ontario’s top manufacturers need to get rid of rust, edges, scaling or excess oils, they turn to Latem Industries. We use a wide range of shot blasting systems to meet your needs - including our overhead conveyor and flat bed roller conveyor systems. Get in touch today to find out what we can do for you!
Friday, September 27, 2019
Have a big batch of metal parts that need finishing? Here’s a solution: let’s get blasted!
Well, we don’t mean that literally, of course. Our brand of blasting is all about cleaning and strengthening the surface of metal parts! We offer a wide range of metal finishing and surface preparation processes, including shot blasting ‒ one of the fastest and most effective ways to clean metal to a mirror-shine.
Shot blasting is a set of technical processes designed to remove various impurities from metal surfaces. We use it to clean contaminants like dirt and oil from mass quantities of parts at once. It’s also a highly efficient method of removing metal oxides like rust or mill scale.
Shot blasting is an important step in preparing metal parts for painting, powder coating or other coating methods that require a clean surface in order to stick. It is practically mandatory in many industries, including the automotive, metal manufacturing, aviation, shipbuilding industries, as well as foundries and the production of welded structures.
Latem Industries utilizes various methods to meet our customers’ specific shot blasting requirements. Here, we’ll compare the applications and advantages of two of the shot blasting methods we offer: tumble blasting and index table blasting.
1. Tumble Blasting
Tumble blast machines are comprised of either a rubber or steel belt that’s driven within an enclosed blasting cabinet. Metal components are placed into the blasting cabinet in batches, where they are continuously impacted by one or more high-pressure streams of abrasive materials (called shots or blasting media.)
We can vary the type, shape, size and density of the abrasive materials to achieve different results. The metal abrasives we utilize in tumble blasting include steel grit, copper shots and aluminum pellets.
During the tumble blasting process, the metal components are also continuously bumping against each other to help knock off surface contaminants and defects.
Advantages of Tumble Blasting
One of the biggest advantages of tumble blasting is the ability to deliver a consistent finish. The combination of tumbling and blasting ensures that even components with difficult geometry (deep recesses or tight angles) receive a perfect surface preparation.
Tumble blasting also allows components to impact each other, accelerating the removal of burrs and sharp edges.
2. Index Table Blasting
Index table blast machines are comprised of a blasting chamber with a large, circular turntable and several smaller ‘satellite’ tables attached to the turntable’s surface.
One or more metal components can be attached to each satellite table. As the large table rotates on its axis, the satellite tables move along within it. Each table can rotate on its own axis independently.
The Index blast table machine we use at Latem Industries is divided into thirds, with a satellite table in each section. A typical blasting operation using this equipment goes like this:
One section of the turntable is loaded with components for shot blasting. The table then indexes or turns, moving the loaded table into the blast chamber for finishing.
This process is continually repeated until all of the parts that require processing have been finished.
Advantages of Index Table Blasting
Index table blasting allows us to process rotationally symmetrical shapes in large batches. The operation is well-suited for components that are fragile and cannot withstand the impact of hitting against each other in a tumble blasting operation. Some of the common applications include cleaning, finishing and deburring of axles, draft shafts and gear assembles.
Tumble Blast vs. Index Table Blast: Which One’s Right For You?
We deliver solutions to most every metal finishing challenge with industry-leading results. To learn more about tumble blasting and index table blasting and find out how we can reduce your processing costs, contact the experts at Latem Industries today!
Friday, July 26, 2019
During the hazy, lazy days of summer, most folks are thinking of relaxing on the beach or by the pool.
At Latem Industries, our summer focuses on removing rust that has unexpectedly occurred on our customer’s parts and equipment.
Why? When the atmospheric conditions are right, rust can form on unprotected metal from the humidity alone. Humidity-based corrosion is something that keeps us busy all summer long.
Unfortunately, many of our customers aren’t even aware of humidity-based corrosion until the rust has already occurred. Don’t let it happen to you! Here’s what you should know about preventing and removing rust and corrosion caused by humidity.
How Humidity Affects the Rate of Corrosion
How does humidity cause corrosion? That’s an important question in the mass metal finishing and parts coating industries. To prevent and manage humidity-based corrosion, we have to first understand how it works.
Metal corrodes at a much greater rate under humid conditions. This happens because the moisture-saturated air reacts with oxygen and electrons on the surface of the metal. The longer metal components are exposed to humid air, the faster they will generally corrode.
This type of atmospheric corrosion can occur when the amount of moisture in the air reaches critical humidity, which is the point at which water no longer evaporates or gets absorbed from the atmosphere. In most conditions, this happens at 80% relative humidity (RH).
But it’s not simply the humidity that causes corrosion; it is the change in temperature along with a significant increase in humidity that causes moisture to form on parts. There are two ways this can happen.
First, the relative humidity increases along with the temperature. Humidity changes during the day largely depending on the temperature. You’ve surely experienced this first-hand on a muggy summer afternoon. Every 50°F (10°C) increase in the temperature can double corrosion activity.
Second, when a surface cools below the temperature of the surrounding air, moisture will form on the surface as condensation. This is likely to happen in most manufacturing facilities as the temperature within the facility cools overnight. Later, when the sun comes up and the temperature rises again, humidity causes moisture to condense on cool, metal surfaces.
The higher the relative humidity, the smaller the temperature difference needed for condensation to form...which sets the stage for corrosion to occur.
How to Prevent Humidity from Creating Corrosion
In a perfect world, we would keep all our precious equipment in a climate-controlled facility that is never affected by the humidity. Of course, most of the metal parts we process aren’t meant to stay in a bubble, so we have to find other ways to protect them.
The simplest and most cost-effective way to protect parts from humidity-based corrosion is to seal them against moisture. This can be accomplished by placing large quantities of parts in Vapor Corrosion Inhibitor packaging, which slowly releases an anti-corrosion compound to protect exposed metal surfaces from corrosion.
Humidity is also an important factor in the surface preparation and application of protective coatings. A high-quality powder coat can seal the surface to guard against corrosion. However, many coatings are not designed to protect metal from high humidity and may even be detrimental in some cases.
How to Remove Humidity-Based Rust
What if the corrosion has already occurred? There is a significant expense and loss of revenue when you are forced to scrap processed parts due to rust.
Fortunately, scrapping parts is seldom the only solution! It’s possible to clean rust from almost any manufactured metal part quickly and cost-effectively, then treat them with a rust inhibitor to prevent it from happening again.
Latem Industries uses various processes to remove rusted areas from processed parts:
The best process for removing rust from mass quantities of parts usually depends on the extent of corrosion and the geometry of the part. Latem has the capacity to clean away rust from millions of parts daily. Whether the part is the size of a thimble or as large a sheet of stainless steel, we have the best processes available to quickly and cost-effectively remove rust.
Friday, June 28, 2019
Shot peening is a time-tested method of enhancing and strengthening the surface of steel. It is employed as a practical and cost-effective way to extend the lifespan and performance of metal parts in numerous industries.
By introducing residual stress on the surface in a controlled manner, shot peening creates a compressive pressure layer that is more resistant to cracking, fatigue, and oxidation.
How Shot Peening Works
Shot peening entails blasting the part with shot (small beads of metallic, glass or ceramic particles) with sufficient force to create tiny indentations in its surface. Each shot acts as a tiny ball-peen hammer loaded with enough kinetic energy to cause plastic deformation - meaning the metal bends slightly on impact but doesn’t chip or fracture.
When this happens, an area of stress is created on the surface of the part. The material directly beneath the indentation, meanwhile, resists and becomes compressed. Each indentation makes the surface of the material stronger and more resistant to cracking.
This process repeats thousands of times during shot peening, gradually building up a strengthened stress layer that encases the entire component!
Shot peening is typically a cold working or cold forming process, meaning the metal is shaped at room temperature or at least below the recrystallization temperature. Other cold working processes include burnishing, roll forming, embossing and extrusion.
Shot Peening or Shot Blasting?
Shot peening is similar to shot blasting...but differs slightly in process and end result.
Both operate by the mechanism of plasticity, changing the surface of the part while minimizing the amount of material removed in the process. However, shot blasting is most often used to clean and prepare components prior to coating. Shot peening, on the other hand, is used to make components stronger.
How Shot Peening is Applied
Shot peening is used to compensate for tensile stresses that occur during machining. Parts that have been through processes like grinding, milling, bending and heat treatment can often benefit from shot peening.
Compressive surface stresses can protect machined components from numerous performance issues, including:
Parts that are commonly shot peened include:
How to Measure Shot Peening Results
Shot peening results are measured using an Almen Strip test.
A flat test strip is placed in the shot chamber to absorb the intensity of the blast, causing it to deform into an arc shape. The height of the arc directly relates to the intensity of the peening blast and the resulting compressive stress.
The intensity (i) of the shot is critical, as overpeening can lead to detrimental effects. Other shot peening parameters include:
Our Shot Peening Services
We understand and appreciate that when our customers are faced with a finishing challenge, they look to Latem for an immediate solution.
Monday, January 21, 2019
Steel surfaces can sometimes exhibit residual mill scale as a side effect of the production process. Though not harmful in and of itself, the presence of scale is detrimental in conditions where corrosion is likely to occur, and it must be removed before a workpiece can be given a protective coating.
This post discusses the role of mill scale in the steel production and coating process, including the fastest way to remove mill scale from surfaces.
Identifying Mill Scale
Mill scale (often known simply as ‘scale’) refers to the thin, flaky texture that forms on the outer surface of hot-rolled iron oxides and metals. It is a by-product of manufacturing hot-rolled metal plates and sheets, occurring as the surface oxidizes during the heating, conditioning and hot rolling processes.
Scale has a distinctive blue-grey colour and a flaky or powdery consistency. It is not a continuous layer, but rather a thin, uneven coat (1mm thickness or less) of mixed iron oxides that chips easily on contact.
Unlike rust, which forms over a long period of exposure to oxygen and moisture, scale forms on all steel and iron products that are hot rolled. The only way to prevent its appearance would be to manufacture them in an inert atmosphere.
Mill scale is not in itself harmful to the workpiece. In fact, in the short term, a layer of scale helps to protect the metal’s surface from corrosion and other negative atmospheric effects. The problem begins when the mill scale breaks – which, given its brittleness, is practicably inevitable during handling, storage or transportation.
Why Mill Scale Must Be Removed
Scale is very fragile, and the moment it cracks, it turns from a protective barrier to a detriment.
Mill scale is less reactive than the steel surface it covers, acting as a cathode to the more reactive material underneath. Once the scale coating breaks (which occurs easily) and moisture comes through, the presence of the scale iron oxide accelerates the corrosion process at the breakage point.
The presence of mill scale is also a hindrance to applying paint or powder coating, which adheres poorly to scale. Left in place, the scale will eventually chip and break the coating’s surface, allowing moisture to penetrate.
It is wasteful to apply a protective coating over a workpiece covered with mill scale. For this reason, scale removal is an indispensable step in the pre-coating process.
Removing Mill Scale from Iron or Stainless Steel
To achieve a smooth, durable coating, mill scale must be removed from an iron or steel workpiece before application. This is true for powder coatings, paints and other finishing techniques meant to protect the surface from corrosion.
Shot Blasting, a method used to clean, strengthen and polish metal, is a fast and cost-effective way to remove mill scale. This service is normally carried out to prepare the surface of steel before applying any coating. Having the steel prepared by shot blasting is generally considered to be the most important factor affecting any corrosion protection system or coating.
At Latem Industries, our diverse line of wheel/suction shot blasting equipment includes monorail, tumble blast, swing table and conveyor to suit your blasting needs.
Latem carries a wide range of shot and grit to service your needs, including:
For further information on shot blasting, or to request a free quote for shot blasting in Southern Ontario, please contact us.
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