Application Stories

Horn Companies Use Invertec V350 for Diverse Projects
By Louis Vitucci, District Sales Manager


Titan Contracting & Leasing Co., Inc., Titan Fabricators, Inc. and National Steel Erection, Inc.Versatility is one of the major strengths of The Horn Companies, headquartered in Owensboro, Kentucky. Consisting of Titan Contracting & Leasing Co., Inc., Titan Fabricators, Inc. and National Steel Erection, Inc., The Horn Companies provide a broad range of services in design, fabrication, field erection, installation, repair and maintenance. Not only are the services offered diverse, so are the industries in which the company operates, including power, pulp and paper, petrochemical, metals and mining. 

The Horn Companies projects range from minor repairs, to multi-million dollar installations involving equipment such as turbine generators, HRSG (Heat Recovery Steam Generator) boilers, tanks, vessels and process piping. With a group of projects this diverse, The Horn Companies are not only versatile in their own capabilities, but require versatility in the equipment they choose.

For this reason, the companies have invested in more than 300 Invertec® V350-PRO units from The Lincoln Electric Company. These inverter-based welding power sources are able to handle multi-process welding applications that require Stick (SMAW), TIG (GTAW), MIG (GMAW), pulsed MIG, flux-cored (FCAW) and even arc gouging. With these capabilities, operators can weld light wall tubing and then change processes to weld heavy wall pipe with just the flip of a switch. In addition, the unit is lightweight and portable, so welding operators can easily maneuver it around the job site and between floors of large structures.

"A large portion of our business is emergency work in power plants to repair leaks in boiler tubes and piping to minimize the outage downtime," said Mike Horn, Owner of The Horn Companies. "In these situations, we need to be able to respond at a moment's notice and get the customer back on line as soon as possible. Previously, we were using transformer rectifier welding units that weigh 600 lbs. each. When we arrived on the site we would have to wait for the customer tosupply a crane, or mobilize a crane from our shop, that could move the welding machine to where it was needed. With the 77 lb. Invertec® V350-PRO units, our operators can take them off the truck, carry them to the problem area and get to work immediately." 

The compact size of the Invertec V350-PRO is also key in the transport of the unit. The compact size of the Invertec® V350-PRO is also key in the transport of the unit. "In the past, the whole flatbed of a truck would be used to hold two welding machines. Now six or more of the lightweight inverters can be transported in one vehicle", according to Bob Lawson, Equipment Manager. 

However, versatility and portability are not the only reasons The Horn Companies selected the Invertec® V350-PRO. Weld quality weighed heavily in their decision to use this unit.

"Many of our customers dictate that we weld to strict AWS and ASME standards," explained David Nuckols, Quality Manager at The Horn Companies. "To ensure code adherence, we perform many types of non-destructive tests. Having quality welds that will not fail is critical, especially since many of our projects involve contents held under pressure. In addition, quality cuts down on production costs because if it's done right the first time, rework is minimal." 

The Invertec® V350-PRO also helps the company meet some particularly challenging application work such as welding thin materials, jobs that dictate precise fit-up, and welding in limited access or confined spaces. 

Diverse Applications

The Horn Companies, with 24 years of service and currently 600 employees, have completed a number of high-profile jobs for well-recognized companies. These include turbine HRSG, piping and tank installations for Burns & McDonnell, in-field maintenance of HRSG boilers and fabrication of pressure parts for Nooter-Eriksen, annual maintenance for Western Kentucky Energy's coal-fired plants, and installation of turbine generators, piping and tanks for GE Power & GE Chemical plants. 

Having a multi-process machine is very important since no job is the "norm" for The Horn Companies. Materials welded with the Invertec® V350-PRO include carbon steel, stainless steel, high nickel alloy, chrome-moly and aluminum. These materials range in thickness from 1/16" to 8" with tensile strengths of 32 to 120 ksi.

One more reason the Invertec models are attractive is the availability of a V350-PRO rack system.One more reason the Invertec® models are attractive is the availability of a V350-PRO rack system. Racks allow four to six welding units to be stored together but require just one input power connection to power the entire rack. In addition, Lincoln V350-PRO rack models designed for use in rack systems meet tough IP23S ratings for outdoor use. The Horn Companies currently uses approximately 40 rack systems in its operations.

In-House Welding

Although 70 percent of the company's welding is done in the field at a customer's location, the remaining 30 percent is in-house fabrication of pressure parts, also using the Invertec® V350-PRO. A particularly challenging application where this multi-process unit has aided production is the fabrication of boiler super heater elements - a heavy wall pipe that requires a TIG root pass followed by flux-cored fill and cap passes. Since the switch to the Invertec for this application, the company has achieved a 20 percent increase in production. 

The boiler super heater element is a massive part weighing up to 500,000 lbs. and can be .095" to 4" thick (depending on pressure requirements). The size, thickness and weight make it especially difficult to set up required J-groove beveling and precise fit-up for the root pass. In addition, much of the welding must be completed in limited access spaces. Compounding these difficulties, many different metals are used in this single assembly - P91 chrome-moly, duplex stainless, and carbon steels P11 and P22. 

With the Invertec units we can now complete the welding work on this part with one power source."With the Invertec® units we can now complete the welding work on this part with one power source," said Horn. "Before, we were using two different power sources - one for the TIG (GTAW) and the other for the flux-cored (FCAW) process. With one power source we have achieved much greater efficiency. In the pressure parts business the market is tight, so we are always looking to add efficiencies to the system to remain competitive. This welding unit has helped us do just that." 

Due to the expertise required to weld specialty alloys, competitors even come to The Horn Companies for assistance in on some tube and pipe welds. "We are one of the top companies in the U.S. that can weld these materials," explained Horn. "The Invertec® V350-PRO plays a big part; if it wasn't for the unit, we probably wouldn't be in this market. The machine gives our operators better control of the weld metal to achieve high quality."

"On one recent boiler super heater replacement project, we had to weld more than 2,000 tube butt joints. All of these welds were made without repair or equipment failure with many hours of continuous work - a major accomplishment attributed to the Invertec® units and the skill of our operators," said Nuckols. 

Welding Equipment

Horn estimates that 80 percent of the company's welding work is now completed using the Invertec® V350-PRO. This 350 amp machine operates on single or three-phase power input and produces either a constant current or constant voltage output. It features Twist-Mate™ style output connectors for easy connection with welding cables and a durable case to stand up to the harsh conditions of the job site.

What makes the Invertec® V350-PRO stand out is the ability to adjust the machine accurately to weld thin materials. "The unit has digital meters which makes it easy to dial in the amps and volts of the machine to get the exact heat required for the weld," said Nuckols. "Our previous machines didn't have these meters and we never received the superior control of the base metal temperature that we do now. The features of the Invertec machines help us eliminate burn-through problems." 

According to Nuckols, the machine offers excellent arc characteristics including a 'soft' and 'crisp' arc for MIG as well as a Variable Hot Start feature for Stick. This features enable the Invertec V350-PRO to produce either a gentle start for thin gauge material or a more powerful start for positive penetration on critical weldments or dirty/rusty material. 

Lincoln's Waveform Control Technology downloads welding waveform outputs targeted for a particular application.Controlling the amperage and voltage on light gauge materials is the original reason the company purchased its first Invertec V350-PRO in May 2000. "I originally brought this machine to their attention because they were looking for something that could weld thin wall material on high nickel alloy linings as thin as 1/16"," said Bobby Simmons, Sales Representative with the local distributor, Modern Supply Company in Owensboro, Kentucky. "Once I demonstrated the product, they were immediately impressed with its size and capabilities. They are always willing to try new technologies and rely on me to suggest new ideas." 

Another significant benefit of the Invertec® V350-PRO is that, with Lincoln's Waveform Control Technology in place, welding waveform outputs targeted for a particular application can be downloaded directly into the machine. The Horn Companies have taken advantage of this by contacting Lincoln Electric's Weld Tech Center in Cleveland, Ohio, to create specially-designed waveforms that are e-mailed to The Horn Companies. This capability has been especially helpful as the company moved into pulsed MIG welding on light gauge material. 

With the inverters, The Horn Companies use Lincoln® manual welding consumables such as Jetweld® 3 (AWS E7024) and Fleetweld® 5P+ (E6010), as well as a low hydrogen (E7018) and Blue Max® stainless steel stick electrodes. The company also has selected Lincoln's SuperArc® L-50 MIG wire electrode (ER70S-3) and Outershield® 71M gas-shielded flux-cored wire electrode (E71T-1) as well as Blue Max® stainless steel wire electrodes. 

The Horn Companies use many other pieces of Lincoln Electric equipment including Idealarc DC-400 and Ranger engine drives.Other Equipment

In addition to the Invertec® V350-PRO inverter power sources, The Horn Companies use many other pieces of Lincoln Electric® equipment in their operations, including Idealarc® DC-400 and DC-600 CC/CV power sources, and engine-driven Rangers, SA-250, SAE 350, Commander 400 and 500 models and a variety of wire feeders. 


Since The Horn Companies' business requires operators to perform more than 500 welding procedures with 900 qualifications, employees must be extremely skilled and able to perform multi-process techniques. To accomplish this, The Horn Companies has established its own welding school where its operators learn and practice welding skills. 

"With their own training center, The Horn Companies are able to take on new jobs and are not afraid to accept jobs requiring the welding of exotic metals," said Simmons. "This is something that sets the company apart from its competitors, who will decline jobs requiring some of this more challenging welding work." 

In addition, Horn Companies operators have been sent to Lincoln's welding school in Cleveland to learn how to better operate and service the machines. 


"We have tried all the major welding manufacturers and find that Lincoln is more reliable and offers better service," said Horn. "When we are out in the field and have problems, we can easily get a Lincoln representative on the phone to walk us through a solution. Since we do work in all 50 states as well as Canada, Mexico, Puerto Rico, Jamaica, Turkey and the Dominican Republic, it is great to know that Lincoln's global network means there are local people that can help us no matter where we are." 

Over the last 25 years, The Horn Companies have grown from a small start-up company to a $100 million per year business.Future

Over the last 25 years, The Horn Companies have grown from a small start-up company to a $100 million per year business. . . and the goal is continued growth. According to Horn, the key to the company's phenomenal success is its reputation for safe, reliable service and excellence in the quality of work they do. The company also strives to be a technology leader in its field, always looking to try something new that can make its operations more efficient. 

"Our goal is partnering with customers to help them with unusual materials or parts, reduce costs and stay competitive. Total customer satisfaction is what we strive for," said Horn. 

Originally written 12/30/02