Overlaying　pinch　roller　has　higher　surface　hardness.　If　the　overlaying　technology　is　improper,　small　circumferential　cracks　may　occur　on　the　welded　surface　and　even　peel　off.　From　failure　analysis,　it　is　indicated　that　the　contents　of　C,　S.　and　0　were　higher　around　the　cracking　area　in　the　deposited　metal.　Optical　microscopic　observation　shows　that　some　cracks　grew　along　the　direction　of　columnar　crystals　and　residual　austenite.　Due　to　high　content　of　inclusions　and　austenite　in　the　deposited　material　and　poor　plasticity　of　the　deposited　metal,　small　cracks　are　easy　to　be　found　at　the　defect　such　as　blue　flecks.　In　addition,　a　large　number　of　cracks　intersect　on　the　deposite　surface,　resulting　in　large　peeled　area.