Tubing for heat exchanger applications must meet very critical criteria – straightness over 60 foot lengths, weld integrity, roundness and even I.D. polished surface with superb weld transition.



United Industries produces heat exchanger, condenser and evaporator stainless steel tubing in OD sizes of ½” through 4”. Manufacturing includes austenitic types such as 304L, 316L, 321, along with Duplex stainless steels such as type 2205. All tubing is produced in-line with length capabilities up to 60’. Wall thickness ranges from .020” up to .145” depending on the OD size. United Industries also has the ability to ID polish up to 60’ for sanitary evaporator applications. United Industries’ QS / ISO 9000 certification assures the highest quality tubing made to our customer’s specifications and requirements.

United Industries' in-line cellular manufacturing process is the appropriate manufacturing environment for heat exchanger tubing. The in-line process enables instant defect detection and continuous inspection for straightness, uniformity of length, weld condition, in-line pressure testing and ultimately in line I.D. polishing.

Manufacturing

All tubing is produced in United Industries’ work cells with the most advanced Hydrogen Bright Annealing units and weld bead cold working equipment. Only approved raw material suppliers are used that provide uniform wall thickness, Rockwell hardness, strength and elongation. The work cells are equipped with precise roll form tooling, regularly scheduled laser alignment and in-line eddy current testers with automatically programmed cut-out saws. This provides tubes that are produced to the tightest OD, ovality, straightness and length tolerances along with a superior weld condition.

Quality / Testing

United Industries follows all requirements and testing procedures per SA/A249 requirements for austenitic grades and SA789 for duplex stainless types. Our work cells are equipped with in-line laser micrometers with constant digital readings that monitor ovality. In addition to the in-line eddy current test, tubes are also 100% air tested before final packaging. OD, length and straightness are held to more stringent tolerances than what is required by ASTM or ASME and are continually checked with ring and plug gages to dimensions provided by the customer / fabricator.

Polishing

For industrial applications, all tubing is provided in the bright annealed condition. When specified for sanitary evaporator requirements, United Industries can furnish tubes up to 60’ in length that are polished in-line at the end of the work cell. The automated system run synchronous with the mill, providing a 180 grit finish. If an OD polish is required, in-line equipment is available.

Product Delivery

Because of the long lengths involved with the heat exchanger and evaporator applications, handling of the tubes is kept to an absolute minimum. The in-line process, along with the location of the work cells upstream from the shipping docks, alleviate the chance of distortion or damage. Orders are produced on the mill and the bundles are then immediately loaded on the truck. Uniform wood supports, consistent banding pressure, cardboard buffers and air ride trailers assure safety and tube quality during transit.