The hardening property of the DIN 17175 X20CrMoV121 steel tube depends on its carbon content and alloy composition content. Chromium and molybdenum, the main alloying elements in the DIN 17175 X20CrMoV121 steel tube, can significantly improve the hardening property of the steel.
In particular, the effect of molybdenum is about 50 times larger than chromium. These alloy elements delay the transformation of DIN 17175 X20CrMoV121 steel tube during cooling and improve the stability of undercooled austenite.
Tempering brittleness refers to the phenomenon of severe embrittlement of DIN 17175 X20CrMoV121 steel tube and its welded joints during long term operation in the temperature range of 350 ~ 500℃.
