Hollow Hexagonal Drill Steel, is a rock drill steel or integral drill steel without tips. Hollow Drill Steel Bar is a type of steel specially used in drill rod manufacture, high intension and toughness.
Integral drill rod without tip shank sizes 82.5 mm*22mm(3 1/4”*7/8”), 108mm*22mm(4 1/4”*7/8”), 108mm*25mm(4 1/4”*1”), 159,*25mm(6 1/4”*1). Lengths: 400mm to 6400mm(1’4”-21’). Head diameters: 27mm to 40mm.
Type
Length(mm)
hex22*108mm
945
1050
1350
1745
1950
ProDrill Hollow Hexagonal Drill Steel has following advantages:
1. High fatigue strength and toughness, high intension.
2. High resistance to wear and permanent distortion.
3. Industrial process of heat treatment.
4. Uniform straightness, eliminating the need for straightening.
Material: Z708(40SiMnCrMo)
Diameter: Hex. 22mm, 25mm, 28mm, 32mm, 38mm.
Length: 800mm, 1600mm, 2400mm, 3200mm or any length according to your requirement.
Package: Wrapped with plastic knitting and then into bundles.
Hot Rolled Hexagonal Hollow Drill Steel
Steel Grade:55SiMnMo
Chemical Composition:
C: 0.92-1.03PCT
Si: 0.25-0.45PCT
Mn: 0.25-0.45PCT
Cr: 0.80-1.20PCT
Ni: 0.25PCT MAX
Mo: 0.20-0.30PCT
S,P: 0.025PCT MAX
Cu: 0.30PCT MAX
Hollow drill steel reduces the expense of impact energy, improves the drilling speed and efficiency, also it can be used for drilling bore hole diameter from 30mm to 41mm usually. Each rods use premium quality alloy steel and advanced industrial process to assure high drilling performance.
Integral Drill Steels, Hollow Hexagonal Drill Rods and Tapered drill rods.
Steel for Tapered Drill Rods and Integral Drill Rods
Tapered connection drill rods and integral drill rods generally refer to those made of H22 and H25 hexagonal hollow steel billets, which are suitable for short-hole drilling operations with small pneumatic or hydraulic rock drills.
Integral drill rods are those with cemented carbide inserts on the head, and they are widely used in both developed and some developing countries. The head of a tapered connection drill rod is conical, and it can only perform drilling work when connected and matched with a drill bit with a tapered hole. Almost all short-hole drilling operations in China adopt tapered connection drill rods, which are also applied in Canada and some other developed countries.
The most widely used steel grade for such drill rods abroad is 95CrMo, which belongs to the alloy tool steel category, with 95Cr and other grades in the same category. Alloy structural steel grades include 40SiMnCrNiMo, 38CrNi3Mo, 38SiCrV, 40MnMo, etc. A few countries also use spring steel such as 55Si2Mn and carburized steel such as 18CrNi3Mo. After long-term screening in China, 55SiMnMo, a type of spring steel, is regarded as an ideal steel grade. T8 and T8Cr steels, which were widely used in the early days, have now been basically phased out.
The main requirements for steel grades of tapered drill rods and integral drill rods are as follows:
High fatigue strength combined with good toughness.
Low notch sensitivity and low fatigue crack growth rate.
Capable of achieving a hardness of around HRC 40 under controlled rolling and controlled cooling or normalized conditions to ensure the elasticity of the drill rod; reaching a hardness of HRC 50–54 after quenching and tempering to prevent the drill shank from mushrooming or bursting under the impact of the rock drill piston.