ASTM A513 (Standard Specification for Electric-Resistance-Welded Carbon and Alloy Steel Mechanical Tubing) is a conventional specification that governs tube for many uses, and hydroformers have been relying on tube made to this standard for many years. However, some hydroformers think that some aspects of this specification aren't appropriate for hydroforming: Some portions of it need to be tightened up and others loosened. Developing a modified specification specifically for hydroforming likely will result in less expensive tubing and fewer failures.
Hydroforming often results in localized thinning. Using engineered tubes—tubes that have a thicker wall where the tube is most prone to thinning—can result in a stronger finished component.