Influence of Tempering Temperature on Impact Toughness of Axle Steel EA4T in High-speed Overloaded Trains

Preparing Charpy V and U type impact samples of steel EA4T tempered at different temperature,respectively,the temper brittleness of steel EA4T was researched by a series of impact test on above samples.The results show that,with the increase of tempering temperature,impact toughness of steel EA4T rises,and there is high-temperature tempering brittleness at about 550 ℃.When the tempering temperature is higher than the region of temperature,the impact toughness value will improve greatly.Also found Charpy V type samples have higher sensitivity than U type impact samples for tempering brittleness.