Specifications

1)high resistance to YAI (yield approach index)
2)cerfication api7-1
3)low price for buyers and good quanlity good price

According to the drill collar material is divided into two kinds of shape and form. 
A type (cylindrical type): Use common alloy steel pipe inside and outside are circular cross-section; 
B-type (spiral): ordinary alloy steel tube outer surface with a spiral groove.

 

	Outside diameter(in)	Yield Strength (MPa)	Tensile strength (MPa)	Elongation (%)	Brinell hardness (HB)	“V” Impact rate (J)
A	3-1/8 ~ 6-3/4	≥758	≥965	≥13	285~341	≥54
B	7 ~ 11	≥689	≥930	≥13	285~341	≥54