Pilgering is a metal forming process used in the manufacturing of pipe and tube. Compared to cold drawing and flow forming, pilgering is generally faster, more cost effective and results in more improved material quality, making it an ideal process in the manufacturing of corrosion resistant alloys. Termed cold pilgering, this method is commonly performed at ambient temperatures to reduce the dimensions of a tube hollow to the desired finished product requirements. In this forming process, the tube is repeatedly compressed between a stationary mandrel and two roller dies.
The mandrel is a tapered cylindrical rod around which the tube is shaped and maintains the inner diameter of the hollow. Roll dies compress the outside of the tube to form the desired outer diameter. The saddle holds the top and bottom roll dies in place, forcing them over the outside of the tube.
After each stroke, the tube is fed forward a small distance and rotated. This reduction in diameter and wall thickness results in a corresponding increase in length, allowing for the production of long length tubing.
Pilgering is generally faster than other manufacturing processes. In one pass, pilgering achieves up to 60% reduction versus up to 20% using the cold draw method. By making greater reductions in one pass, pilgering minimizes the number of required operations and lowers the amount of resulting scrap material. The pilger method also results in improved material quality relative to alternative manufacturing processes. Pilgering achieves tighter tolerances and a better surface finish. Imparting cold work also refines the grain structure, increasing the strength of the material and causing less through wall hardness variation and anisotropy.
Though pilgering is a common process for CRA tubulars, corrosion resistant alloys manages the timeline of our operations a little differently. Our unique just in time manufacturing model provides much needed flexibility when speed, reliability, quality and innovation are pivotal to project success. Manufactured products are available in as quickly as a few days. By maintaining feedstock at various stages, CRA significantly reduces lead times and improves delivery reliability.
CRA ISO certified API 5 CRA licensed and able to accommodate any key third party inspection points or customer quality assurance requirements. We offer custom dimensions and limited quantities that are typically unavailable through traditional mills. CRA Just in Time Mill manufacturing means connecting our customers with the right product in the right quantity at the right time.