Type A : cylindrical
Be made of alloy steel and cross sections of the inside and outside pipe are both round.
Type B : spiral
Be made of alloy steel and the outside pipe has spiral grooves.
OD: 79.4-171.4 mm 3-1/8~6-3/4 inch
yield strength:≥758 Mpa tensile strength:≥965 Mpa HB:285-341
177.8-279.4 mm 7-11 inch
yield strength:≥689 Mpa tensile strength:≥930 Mpa HB:285-341
Type C: non-magnetic
Be made of stainless alloy steel with rather low magnetic permeability and the cross sections of the inside and outside pipe are both round
OD: 79.4-171.4 mm 3-1/8~6-3/4 inch
yield strength:≥758 Mpa tensile strength:≥827 Mpa
177.8-279.4 mm 7-11 inch
yield strength:≥689 Mpa tensile strength:≥758 Mpa
