How it’s Fabricated: Trailer Flanges

Most manufacturers agree that the highest-quality trailer flanges today are made from High Strength Low Alloy (HSLA) steel. These are available in a variety of grades, GR50, GR80, GR100 and GR130, among them. As their name suggests, these important metals provide greater strength than non-HSLA steels, giving trailer designers the ability to use less material without sacrificing load-bearing and fatigue qualities. The result is lighter weight, greater fuel efficiency, and improved safety.

Benefits of High Strength Steel:

Step 1: Pickling

Pickling is a chemical process that uses acid and heat to remove scale from hot rolled steel.  Unlike shotblasting, pickling removes the entire oxide jacket, but this leaves the surface reactive and susceptible to rust. Oiling is the most common surface treatment to prevent rust, but it must be applied properly to minimize waste and achieve the desired results. Steel Warehouse uses an electrostatic oiler that provides excellent control over the amount of oil applied, delivering just enough to prevent rust without creating excessive smoke during laser and plasma cutting. If desired, heavier oil applications can be used to enhance formability and reduce tool wear during the manufacturing process.

Step 2: Slitting

Steel producers use the slitting process to change coil widths. It allows for very exacting dimensional control and infinite target width selection. For instance, edge trimming is a type of slitting that reduces variation in mill coils, which can deviate up to 1-1/2” in width; after edge trimming, this variation is reduced to 0.040" in most cases. Another type of slitting converts a wide coil into multiple narrower ones—a 48" mill edge coil could be cut into four 12" wide coils, seven 7.853" coils, or a combination of unique widths based on customer requirements.

Step 3: Blanking

Blanking, also known as narrow cut-to-length, is a common operation on slit coils. The first step is to feed the coil into a leveling cassette to remove any residual memory and produce a very flat strip.  The strip is then cut to the desired length. The typical length for blanked trailer flanges is around 40 feet, but custom lengths can be ordered to accommodate the trailer manufacturer’s requirements, with the minimum length around 24 inches. The slit edges can also be modified during the blanking process—a technique called edge conditioning— to produce a gently rounded edge.

Step 4: Flange

The work has just begun. The HSLA trailer flange blanks are then packaged according to the customer’s needs for shipment to fabricators and OEMs of heavy-duty equipment within the agricultural, construction, and mining industries. Once there, the custom flanges are further trimmed to length, notched and beveled as necessary, then precision welded onto the trailer frame. The resulting joints are then smoothed to remove any weld spatter. 

Holes might be added for cabling and hoses at this time, as well as brackets or threaded fasteners. The fabrication step now complete, the trailer with its numerous flanges is primed and painted to prevent corrosion. The top deck is bolted in place, the wheels, electrical wiring, and braking systems installed and tested, and the finished trailer delivered to the distributor or end user.