Qualimetry Rating of Hot-Rolled Pipes

Abstract

The evaluation quality rating of hot-rolled pipes using complex quality indicators is considered. The weighted averages of arithmetic and geometric complex indicators as well as with probabilistic indicators of access to allowable intervals on the example of oil-grade pipes are compared. It is shown that all the indicators have similar values. A complex rating of the properties of pipes manufactured by current and improved technologies was conducted. The impact of individual indicators on the quality of pipes as a whole was estimated. A comparison of complex indicators of the quality of pipes rolled on two technologies made on the scale of Harrington's desires: the current technology indicator corresponds to a sufficient level of quality in accordance with the normative documents. The indicator of the improved technology corresponds to an acceptable and good level of quality.

Method of Speed Mode Correction of Rolling Pipes in the Reduction Mill

“…The second direction is connected with the adjustment of the speed mode of the reduction mill in order to create additional tensions and reduce unwanted wall thickening during rolling of the end areas. Many different techniques and methods for adjusting the speed mode of a reduction mill have been developed (for example, [1,[8][9][10][11][12][13][14][15][16][17][18][19][20]), but they do not fully consider the shape and dimensions of the actual thickened ends formed on a specific pipe-rolling unit and need to be clarified.…”