铝热-离心法制备的不锈钢内衬复合钢管不锈钢层裂纹成因分析

STRESSAND CAUSE OF CRACK FORMATION IN STAINLESSSTEEL LINED COMPOSITE STEEL PIPE BY CENTRIFUGAL- THERMIT PROCESS

研究了铝热 -离心法制备的不锈钢内衬复合钢管中的残余热应力及不锈钢层的组织结构 ,分析了复合钢管不锈钢层中裂纹产生的原因。研究表明 。

The microstructure of stainless steel layer in the composite pipe prepared by centrifugal-thermit process was investigated. The thermal stress distribution in the composite pipe during the cooling of fabrication process was analyzed by means of finite-element method. It is demonstrated that the high thermal stress and the brittleness of steel layer, caused by nonmetal inclusions and precipitated phases, were responsible for the cracking of the stainless steel layer. During cooling, the thermal stress was high and would be beyond the tensile strength of the stainless steel layer to cause cracks if it was not relaxed by the plastic deformation. By increasing the plasticity and reducing the thermal stress of stainless steel layer, the cracking could be avoided.