We could make drill pipes used for raise boring machine, the normial size is from 5"~17-1/2".

The drill pipe has integral type and double pin type. According to the customers' requirements, we could

Choose AISI 4330 MOD and AISI 4145H material, their technical specification is following:

AISI 4330 MOD:

Tensile strength: Min 1040-1230 Mpa

Yield strength: Min 965 Mpa

Elongation in 2": 10.7% Min. (T), 15% Min. (L).

Reduction of area: 32% Min. (T), 45% Min. (L).

Below surface: 321-364 BHN.

Radial notch: 90J (L) Min., 50J (T) Min

AISI 4145H

Tensile strength: Min 1010-1150 Mpa

Yield strength: Min 760 Mpa

Elongation in 2": 15% Min. (L).

Reduction of area: 45% Min. (L).

Below surface: 295-342 BHN.

Radial notch: 48J (L) Min

Main parameters

Norminal size	Shoulder to shoudler length	Thro bore dia.	Inside dia. Of tube	Length of tube	Shoulder to first spanner flat	width of spanner flat	shoulder to end of spanner flats	dimension across spanner flat	connections*	weight
A	B	C	D	E	F	G	H
in mm	in mm	in mm	in mm	in mm	in mm	in mm	in mm	in mm		kg
8" 203.2	48" 1219.2	4 3/4" 120.7	6 5/32" 156.4	39 1/2" 1003.3	1 1/2" 38.1	2 3/4" 69.8	8 1/4" 209.6	6 7/8"174.6	6 3/4" R.B.-DI22	175
10" 254	60" 1524	4 3/4" 120.7	7 1/16" 179.4	50 1/4" 1276.4	1 1/2" 38.1	2 3/4" 69.8	8 1/4" 209.6	8" 203.2	8 1/4" R.B.-DI22	352
11 1/4" 285.8	60" 1524	4 3/4" 120.7	7 11/16" 195.3	48 7/16" 1230.3	1 1/2" 38.1	3 1/2" 88.9	10" 254	9" 228.6	9 1/4" R.B.-DI22	465