Effect of Welding Heat Input on Microstructure and Mechanical Properties of Coarse-grained Heat Affected Zone in AH36 Steel Containing Different Nb Contents
The work aims to investigate the weldability of AH36 steel containing different Nb contents under high heat input conditions.The effect of heat input on microstructure,hardness and impact toughness at room temperature of coarse-grained heat affected zone(CGHAZ)in AH36 steel with different Nb contents was investigated by optical microscopy,field emission scanning electron microscopy,transmission electron microscopy,vickers hardness tester and impact tester.The electrogas weld-ing experiment was used to evaluate the weldability of AH36 steel plate produced industrially.With the increase of heat input,the prior austenite grain size increased,the content of ferrite side plate and bainite decreased,the grain boundary ferrite coars-ened and the hardness tended to drop.The impact energy at room temperature of CGHAZ with heat input of 140 kJ/cm was higher than that of heat input of 80 kJ/cm,but close to that of 200 kJ/cm heat input.Under the same level of heat input,the bain-ite content of CGHAZ in steel with low Nb content was lower than that with high Nb content.Therefore,the hardness and im-pact toughness at room temperature of CGHAZ in steel with low Nb content were lower and better than that with high Nb con-tent,respectively.The impact energy of each zone of welded joint produced by electrogas welding satisfied the requirements of classification society.The weldability of AH36 steel with low Nb content is higher than that with high Nb content.The AH36 steel plate produced industrially has good weldability.
Nb microalloyingcoarse-grained heat affected zoneimpact toughnessacicular ferriteelectrogas welding
万方数据
维普
