320.253.2699 sales@c4weld.com

Specialty & Critical Welding

Experts in Specialty & Critical Welding

We bring your ideas to life, save money by curbing unnecessary fabrication costs, and weld a variety of metals ranging from carbon steel to titanium. We stand behind our work through strategic partnerships and an accredited staff of experts—from degreed engineers to certified welders and AWS certified weld inspectors.

We welcome unusual design challenges that require unique sizes, shapes, or exotic metals. We use our design, welding, and manufacturing engineers as well as Certified Welders to incorporate manufacturability into your product.


We handle every detail of your project, and that’s how we’ve earned a national reputation for welding excellence. We follow qualified Welding Procedure Specifications (WPS), and provide:

  • Design and Manufacturing Engineering support
  • Experienced, Certified Welders:
    • Highly Skilled TIG, MIG, Sub-arc, and Stick
    • Multiple Certifications
    • Versatile, Proficient, and Experienced
  • Certificate of Compliance (COC) documentation
  • Manufacturing documentation

The C4 Welding Advantage

Value Engineering

Cost-Reduction Analysis & Design

Critical Welding

National Reputation for Weld Excellence

Performance Testing

Products Tested to Expected Performance

NDE Inspection

Evaluation without affecting serviceability

Welding Qualifications

You won’t find the same level of internal expertise when dealing with most welding companies. Our welding engineers are professionals, and we maintain the qualifications to meet the specifications of your critical welding projects. If you don’t see something on the list, please ask us. For more information, contact us. As a rule, C4 Welding’s weld procedures are qualified in accordance with these three specifications:

  1. ASME Sections VIII & IX
  2. AWS D1.1 (Steel), D1.2 (aluminum), D1.6 (stainless steel), D14.1 (material handling) & D17.1
  3. NAVSEA S9074‐AQ‐GIB‐010/248 (MIL‐STD‐248) and S9074‐AQ‐GIB‐010/278 (MIL‐STD‐278)

At the same time, many procedures conform to customer‐specific and other agency‐required standards such as:

  • NACE MR01‐75/ISO 15156‐X
  • DNV (Off‐Shore Standard) and DNV‐OS‐E101 (Drill Plant)
  • API Specification 6A/16A ASME B31.1 (Power Piping)
  • ASME B31.3 (process piping)
  • Ground Combat Vehicle Welding Code (aluminum 12472301) and (steel 12479550)

The previous lists were not intended to be all‐inclusive. Our highly skilled welding operators are cross‐trained and certified for a wide range of welding codes and processes. Please contact us if your specific welding code or process is not listed.

Weld Processes

GTAW (Tig) | GMAW (Mig) | FCAW (Flux Core) | SMAW (Stick) | SAW (Sub‐Arc) | RSW (Spot) | OXY‐Fuel


Our welding engineers and certified welders can support and weld a wide range of materials such as:   Carbon Steel | 1008, 1010, 1011, 1015, 1018, 1020, 1040, A36, A366, A569, A588, A622, A786, A53, A500, A106, A335, A513, A333, 1026, 1027, A335 High‐Strength Steels | Domex 100 XF, HY 100, A656 Gr., 80 A565 Gr. 80, A514, INX‐50, Ex‐Ten 50, A572 Gr. 50, A588 Mod, T‐1 Type A, T‐1 Type B, T‐1 Type C, A285, A515, A516, A715, A606, Crane Materials Stainless Steels | 304, 304/304L, 316/316L, 317, 321, 347, 405, 409, 410, 630, 15‐5, 17‐4, Duplex Alloy Steels | 4130, 4140, 4320, 4340, A204 GR B, SA 387, A517, 8620, A331, A286, Cor‐Ten A, Cor‐Ten B Nickel Alloys | AMS 5870, INCONEL 617, INCONEL 625, INCONEL 601, Monel 400, B443, A494, Hastelloy, Invar 36, Nitronic 50, Cobalt‐chrome, Stellite, 2.25cr‐1mo (Chrome Alloy), .5cr‐.5mo (Chrome Alloy), 1cr‐.5mo (Chrome Alloy) Aluminum | 3003, 5052, 5083, 5086, 6005, 6061, 6063, 6105, 356 Cast Other Materials | Titanium Grade 5 ‐TI‐6AI‐4V, A‐487 Grade 9, A27, Ductile Iron 60‐45‐15 Class M2, Ductile & Grey Iron A‐48 or A536 The previous lists were not intended to be all‐inclusive. Please contact us if your specific material is not listed.

Quality Systems

  • Standard (for all non‐pressure vessel applications). Our Standard quality   program is qualified to MIL‐I‐45208 and is ISO 9001:2015 certified.
  • ASME. For shop and field fabrication of pressure vessels, conforming to Section VIII, Division I (ASME “U” Stamp) and repairs and alterations of “U” Stamped Vessels in accordance with the National Board Inspection Code (NBIC “R” Stamp).
  • Certificates of Authorization: “NB” Mark (National Board); “U” Stamp; “R” Stamp.

Quality Assurance

AWS Certified Weld Inspectors High pressure water testing of weldments Quality is the highest priority for us. This is demonstrated by having AWS Certified Weld Inspectors (CWI) on staff. The benefits of doing so include the following: the ability to conduct in‐process inspections both during welding cycles and at critical control points; and the opportunity to document findings throughout the process. This way, we can provide documentation at any point during the process to validate that the product is being manufactured to the drawings and specifications you provided. The result is a proactive, well‐managed program that ensures top‐quality results, each time. Following are tests performed in‐house:

  • Magnetic Particle (MT)
  • Liquid Penetrant (PT)
  • Ultrasonic Test (UT)
  • Visual Test (VT)
  • Functional, Hydro, and Proof Testing

ISO 9001:2015 Certified Quality Systems


Street Address: 11 Industrial Blvd.

Sauk Rapids, MN 56379 USA


Main Phone: 320.253.2699

Fax: 320.253.4804


Sales-Related Inquiries: 320-253-2699 

Email: sales@c4weld.com


Human Resources-related Inquiries:

320-253-2699 Email: hr@c4weld.com



C4 Welding, Inc. BBB Business Review