Drill Collar

Drill collars are made of AISI 4145H or 4145H modified alloy steel. And it is used between the drill pipe and the bit in the drill stem. The chemical composition should be controlled strictly during the refining and forging process. It is used to put weight on the bit so that the bit can drill.

Drill Collar Number and Connection Label	OD	ID	Length	BD	Referenced bending Strength Ratio
	mm	mm	Length	BD
		+1.59	m	mm
		+1.59	+152.4mm	mm
NC23-31	79.4	31.8	9.14	76.2	2.57:1
NC26-35	88.9	38.1	9.14	82.9	2.42:1
NC31-41	104.8	50.8	9.14 / 9.45	100.4	2.43:1
NC35-47	120.6	50.8	9.14 / 9.45	114.7	2.58:1
NC38-50	127.0	57.2	9.14 / 9.45	121.0	2.38;1
NC44-60	152.4	57.2	9.14 / 9.45	144.5	2.49:1
NC44-60	152.4	71.4	9.14 / 9.45	144.5	2.84:1
NC44-62	158.8	57.2	9.14 / 9.45	149.2	2.91:1
NC46-62	158.8	71.4	9.14 / 9.45	150.0	2.63:1
NC46-65	165.1	57.2	9.14 / 9.45	154.8	2.76:1
NC46-65	165.1	71.4	9.14 / 9.45	154.8	3.05:1
NC46-67	171.4	57.2	9.14 / 9.45	159.5	3.18:1
NC50-70	177.8	57.2	9.14 / 9.45	164.7	2.54:1
NC50-70	177.8	71.4	9.14 / 9.45	164.7	2.73:1
NC50-72	184.2	71.4	9.14 / 9.45	169.5	3.12:1
NC56-77	196.8	71.4	9.14 / 9.45	185.3	2.70:1
NC56-80	203.2	71.4	9.14 / 9.45	190.1	3.02:1
65/8 REG	209.6	71.4	9.14 / 9.45	195.6	2.93:1
NC61-90	228.6	71.4	9.14 / 9.45	212.7	3.17:1
75/8 REG	241.3	76.2	9.14 / 9.45	223.8	2.81:1
NC70-97	247.6	76.2	9.14 / 9.45	232.6	2.57:1
NC70-100	254.0	76.2	9.14 / 9.45	237.3	2.81:1
85/8 REG	279.4	76.2	9.14 / 9.45	266.7	2.84:1