5qD or 20Mn Q345qD or DG20Mn Q420qD or 35CrMo 35CrMo 34Cr2Ni2Mo 50#-250# Q420qD 35CrMo 34Cr2Ni2Mo 30Cr2Ni2Mo Standard：GB10051-2010 same as DIN15400 ◆ Mechanical standard Hook Grade Carbon Steel Alloy Steel Upper yield strength Mpa Impart energy Akv(ISO-V)/J Upper yield strength Mpa Impart energy Akv(ISO-V)/J 20℃ ―20℃ 20℃ ―20℃ Vertical Cross Vertical Cross Vertical Cross M 235 55 31 39 21 ― ― ― P 315 ― ― ― （S） 390 390 35 27 T ― ― 490 35 27 （V） ― ― 620 35