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GIII Quality Integral Chisel Drill Rod
- Hex Shank: 22*108mm
- Lengths:400mm to 6400mm(1’4”-21’)
- Head diameters: 27mm to 42mm
- Steel Code: 55 SiMnMo ( GIII )
- Carbide grade : YK20
55 SiMnMo ( GIII ) Steel materials introduction :
55SiMnMo steel is a special steel grade developed in China for Tapered Drill Rods and Integral Drill Rod used in shallow hole rock drilling. It is a bainitic steel, improved from 55Si2MoV. Alloyed with silicon and manganese, it has high elastic limit and fatigue limit.
The addition of molybdenum strongly inhibits the transformation of austenite to pearlite in the steel, which is beneficial to the formation of bainite. At the same time, molybdenum can reduce the overheating sensitivity and graphitization tendency of silicon-containing steel. Under hot-rolling and air-cooling conditions, a microstructure mainly composed of granular or lath bainite and carbon-rich retained austenite is obtained.
Studies by Chinese scholars have shown that whether the carbon-rich retained austenite in 55SiMnMo steel is in strip or block form, it has a good inhibitory effect on the propagation of fatigue cracks. A large number of tests, production and application have proved that the H22mm Integral Drill Steel and Tapered Drill Rod made of 55SiMnMo steel has set the highest record for the service life of cone-connected drill rods in China.
Tapered Drill Rods and Integral Chisel Rod generally refer to those made of H22 and H25 hexagonal hollow drill steels. They are suitable for shallow hole drilling operations with small pneumatic rock drills or hydraulic rock drills. Integral drill rods are those with Cemented Carbide Inserts at the head, which are widely used in developed countries and some developed countries.
The head of a Tapered drill rod is conical and can only be used for drilling after being connected and matched with a drill bit with a conical hole. Almost all shallow hole drilling in China uses tapered drill rods, which are also used in Canada and some developing countries.
The most widely used steel for such drill rods abroad is 95CrMo, which belongs to the category of alloy tool steels. Similar ones include 95Cr, etc. Alloy structural steels include 40SiMnCrNiMo, 38CrNi3Mo, 38SiCrV, 40MnMo, etc. Individual countries also use spring steel such as 55Si2Mn and carburized steel 18CrNi3Mo. After long-term screening in China, it is considered that the spring steel 55SiMnMo is a relatively ideal steel grade. The T8 and T8Cr steels, which were widely used in the early days, have now been basically eliminated.
The main requirements for steel grades for Tapered drill rods and Integral drill rods are:
(1) High fatigue strength combined with good toughness.
(2) Low notch sensitivity and low fatigue crack growth rate.
(3) It can achieve a hardness of about HRC40 in the controlled rolling and controlled cooling or normalized state to ensure the elasticity of the drill rod. After quenching and tempering, it should reach a hardness of HRC50~54 to ensure that the shank does not have pile-up or burst under the impact of the rock drill piston.
(4) Small decarburization tendency when heated.
Rock drilling tools ProDrill provides a variety of integral drill steel and plug hole rods in a full range of lengths and steel hex diameters for all of your hand-held pneumatic drilling needs.
Integral drill rod's 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.
Integral drill rod, another name called integral drill steels, integral rods are used by hand held rock drill in granite and marble quarries, underground mining, for small blasting hole drilling shank H22x108mm, H19x108mm, and standard hex. Bit diameters include 20-42mm,different lengths are available from 400mm to 6000mm usually.
It can reduce 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 excellent quality tungsten carbide to assure.
