Preparing castings and forgings ready for the subsequent processing steps presents some of the toughest surface finishing challenges. Shot blasting machines can handle all of these tasks from removing residual sand, casting shells, flashing, die marks, or scale.
Whether cast iron, steel, stainless steel, super alloys, titanium, aluminum, zinc, or magnesium, the comprehensive portfolio of Rosler blasting systems for the forge and foundry industries can develop the optimal process for any requirement.
Principle & Popularity
Shot blasting is an essential part of most forge and foundry operations and has been used since the late 1800s. This specialized surface finishing process throws small metal (or mineral) pellets, called blast media, onto the surface of a work piece at incredibly high speeds, ranging from 200-800 feet per second.
Surface preparation can account for up to 40 percent of structural steel painting and repainting jobs. As Rosler’s Structural Steel FAQ series has already established, the life of anti‐corrosion coatings on a steel surface depends to a large extent on how thoroughly the surface has been prepared for painting.
Properly evaluating the surface of structural steel surfaces for coating before and after shot blasting will help balance the cost of preparing, repairing, and monitoring structural steel throughout its impressive lifespan.
This installment of our Structural Steel FAQ series will answer How are rust and mill scale evaluated pre‐ and post‐blast?
Widely used standards were developed to visually assess the initial surface conditions and the quality of the required surface preparation relative to the initial steel surface conditions.
With more than 80 years of experience, Rosler has developed, installed, serviced, and provided consumables for shot blast systems for a variety of industries and applications.
When a Polish manufacturer of complex steel weldments was ready to invest in a new shot blast machine, key selection criteria included quality, capacity, high equipment uptime, and integration into the existing manufacturing flow. As an essential part of the pre-treatment operation for a cathodic painting line, the system also needed to produce optimal surface preparation results within an interlinked workflow in a 3-shift operation.
In order to stand up to the harsh demands of the construction, shipbuilding, and heavy equipment industries, the most appropriate type of surface preparation must be undertaken to ensure the best shot blasting results possible.
As always, consult a surface finishing expert such as Rosler to discuss your specific components, their condition, and the desired outcome for your structural steel applications.
We turn to another FAQ about structural steel: What type of surface preparation is required prior to shot blasting?
The answer depends on the condition of the component.
Structural steel components are used in many industries, including construction and construction equipment, shipbuilding, and the production of all kinds of heavy-duty vehicles, trucks, railway vehicles, and agricultural implements. In the construction of bridges, building of ships, or production of equipment that must withstand heavy loads, steel is selected for its strength and durability.
To live up to its full potential and prevent premature failure, the steel must be guarded against corrosion with a protective coating. Shot blasting plays an indispensable role in preparing the steel surface for such coatings. Partnering with a shot blasting expert such as Rosler can help you determine the shot blasting equipment, blast media, and processing required for your structural steel components.
In a series of blog posts, Rosler will answer the most common questions about the surface preparation and coating of structural steel.
We begin with a basic question: Why do structural steel components need to be prepared for protective paint coating?
The answer, in short, is for the best coating results and longevity.
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Modern metal fabrication operations aren’t like the fab shops of old. Many are clean, well lit, with employees working in fresh, filtered air. Yes, some operations in fabrication are, well, just plain dirty—and manual blasting is a prime example. The work isn’t pleasant, requires protective gear, and if the booths aren’t maintained or set up properly, they can constrain workflow in a serious way.
Options in blasting automation abound, but before diving into all that technological wizardry, try laying some groundwork by answering a fundamental question: What must the blasting operation accomplish?
Shot Blasting Versus Shot Peening
Shot blasting (or just “blasting” if using a different media other than shot) prepares a metal surface while shot peening aims to change the metal’s properties (see Figure 1). Certain aerospace applications require precise levels of stress relief (or other changes to material properties), and they use specialized shot-peening technologies to achieve it. Precision shot peening of landing gears is a prime example, with the process optimizing surface stresses, eliminating microcracks and the stress risers around them.
Most metal fabricators employ blast cleaning for the vast majority of their applications, cleaning and preparing a metal surface for the next manufacturing step, usually painting. If a beam or plate isn’t blasted correctly, paint won’t adhere properly. However, some fabrication operations do employ a kind of peening—not as precise as high-end peening applications, but it’s peening nonetheless, with the media impacting the surface and causing compressive stresses that aim to change the material’s properties.
B+S handles a broad range of work pieces with different shapes, made of different materials, requiring different finishes, and coming from all kinds of industries. To create a streamlined and one-stop supplier, B+S chose to work with Rosler for its surface finishing equipment and consumables.
Shot blasting is a specialized surface finishing process where small metal (or mineral) pellets, called blast media, are thrown onto the surface of a work piece at incredibly high speeds. With rates of speed ranging from 200-800 feet per second, the impact on the work pieces from this process is what produces the desired surface finishing effect.
The process components of a shot blasting system include a shot blast machine, raw and finished work pieces, blast media, dust, and other byproducts. Rosler has more than 80 years of experience in developing comprehensive shot blasting systems.
For nearly a decade, Sales Representative and Interim Product Manager of Turbine Blast Equipment Zack Murray has been one of Rosler’s top shot blasting experts.
Working with customers and our global Customer Experience Centers, he helps develop and test surface finishing machines and media in addition to dialing in specific process parameters.
At times, adhering to the Rosler motto and guiding principle of “finding a better way…” can be difficult and complicated. Luckily, Murray and the entire Rosler team are committed to delivering world-class surface finishing equipment, consumables, and service in a variety of industries.
In this post, Murray shares the most challenging issue he has tackled at Rosler and how the team developed a solution.