METHOD FOR TRACING AND INVESTIGATING SURFACE FLAW OF BILLET FOR HOT ROLLING

摘要

PURPOSE:To detect exactly the degree of harmful influence onto a product according to the form of surface flaws by embedding metals having the rolling deformation form different from the rolling deformation form of a billet before and behind the surface flaws of the billet and investigating the flaws between such metals after rolling. CONSTITUTION:Holes are drilled at the suitable points before and behind various base flaws such as crack 2a, pinhole 2b, scab 2c and side face flaw 2d on the surface of the billet 1 consisting of a carbon steel, etc. and tracers A, B, C, D consisting of a stainless steel, etc. having the rolling deformation form different from the rolling deformation form of the billet 1 are embedded therein. The actual condition how the respective flows 2a, 2b, 2c, 2d change during the plastic deformation after the rolling is investigated in this state. The cause for whether the surface flows of the product arise from the surface flaws of the billet or are generated during the rolling stage is elucidated by such tracing and investigating method.