METHOD OF STRAIGHTENING THIN-WALL CYLINDRICAL ARTICLES FROM MARAGING STEELS Russian patent published in 2012 - IPC C21D9/40 

FIELD: process engineering.

SUBSTANCE: invention relates to machine building and may be used for straightening cylindrical maraging-steel thin-wall articles. To ensure required diametral sizes of thin-wall cylindrical articles from maraging steel, split mandrel as-hardened from alloyed steel is fitted on article, its thermal linear expansion factor being lower than that of the article in the entire temperature range of heating it to maraging temperature. Mandrel is composed of two halves tightened together by common axle with no clearances while opposite ends are bolted together in fitting it on article. Split mandrel ID is selected to equal article OD. In joint heating, hold and cooling in whatever time, interference between mandrel and article is maintained. In maraging, article is hardened while article shape set by mandrel is preserved. After cooling of mandrel-article system in air, mandrel is withdrawn.

EFFECT: provision of required diametral sizes.

2 tbl, 1 ex