An Investigation of the Development of Defects During Flow Forming of High Strength Thin Wall Steel Tubes

Effect of heat treatment of preform on the mechanical properties of flow formed AISI 4130 Steel Tubes—a theoretical and experimental assessment

“…It has been observed that hardened and tempered preforms with hardness less than 215 HB does not give the speci®ed mechanical properties while preform with hardness more than 245 HB develops ®sh scaling and cracking as reported by the authors [21].…”

“…Typically, a very soft preform would have very good¯ow formability, but will develop poor strength after¯ow forming. On the contrary, a very hard preform may not¯ow form at all to the required size and shape of the ®nal product or may develop cracks during¯ow forming [21]. Hence, optimization of heat treatment of preform material consistent with the ®nal required mechanical properties of the¯ow formed tube is important.…”

A Review of Flow Forming Processes and Mechanisms

“…In this way, it is possible to evaluate S/L ratio for establishing dominant flow between axial and circumferential deformation. This methodology has been tested and confirmed valid for different conditions and materials by several papers, through numerical and experimental method [9,12,20,23,27,28]. [27] extend this work in order to obtain a detailed analytical expression of contact zone.…”

“…The authors described the phase of production through a flowchart and they use analytical methods for determining the preform dimensions and the expected ultimate strength. [9] investigate the insurgence of defects in flow forming steel tubes production. [10] perform different test on flow formed pressure vessels in AISI 4130 steel in order to evaluate the effect of the heat treatments.…”

Experimental studies on bursting pressure of thin-walled flow formed pressure vessels

“…A three-pass reverse¯ow forming method has been followed for the tube with a total thickness reduction of 88%. The¯ow forming sequence followed and the method used to prepare the tensile test specimens from the¯ow formed tube are given in [14].…”