Established in 1975, O’Brien Steel Service is stocked and equipped to service customers of all sizes, ranging from small job shops to the largest OEMs in the USA. Our legacy is rooted in hard work, exceptional service, and long-lasting partnerships with both our customers and suppliers. With the dedication of our 400+ motivated employees, we’re ready to meet your most demanding requirements!

O’Brien Steel operates four service center locations:

• Peoria, IL
• Milwaukee, WI
• Wausau, WI
• St. Louis, MO

In addition, we operate four steel processing locations:

• Lacon, IL – heavy machining, welding, fabrication, and painting
• Minonk, IL – heavy welding, fabrication, and painting
• Congerville, IL – light gauge welding, fabrication, and painting
• Certified Heat Treating – Peoria, IL – commercial thermal processing

Milestone events:

• 1975: Founded by Joe & Marge O’Brien, East Peoria IL
• 1978: Relocated to current headquarters, Peoria IL
• 1988: Founded Certified Heat Treating Co., Peoria, IL
• 2001: Constructed plate processing center, Peoria IL
• 2008: Acquired Rohn Products, LLC, Peoria, IL
• 2012: Constructed long products distribution center, Peoria IL
• 2012: Acquired Wausau Steel, Wausau
• 2012: Opened Milwaukee facility, Cudahy WI
• 2016: Acquired Meta Tec Inc., Lacon IL

Precision machining and machined fabrications

• 2020: Acquired Durre Brothers Welding & Machining, Minonk IL

Heavy fabrications

• 2020: Acquired Premier Fabrication, Congerville IL

Light fabrications

• 2022: Implemented Microsoft Dynamics D365 ERP system
• 2023: Acquired Sligo Steel, Madison IL
• 2025: Celebrated 50 years in business