Influence by Tempering Temperature on Performance of 26CrMo4s/2 Drill Pipe Blank

The phase transition point of the 26CrMo4s/2 drill pipe blank is measured, when the tempering temperature is going up. The study focus is on the influence by variation of the tempering temperature on tensile strength and Charpy impact of the material. The study reveals that along with the increase of the tempering tem- perature, the strength of the material goes down, whereas its plasticity and toughness get up. And when the tempering temperature gets higher than 620 ℃, the strength of the material is getting down more obviously than before. After being heat treated properly, the 26CrMo4s/2 steel will be satisfactory to the requirements for the three steel grades, i.e., E, X and G as specified in ANSI/API Spec 5DP—2009. And after being tempered with appropriate temperature, impact value of the material will go up above 100 J(7.5 mm×10 mm, 21 ℃).