The mid-1960s, because of the lack of Cr, Ni resources, research new steel alloy guiding ideology is to develop SiMnMo series, developed 35SiMnMoV steel threaded Rod as our recommendation of steel, and has been extended so far. But as the threaded steel drill rod, if the use of heat treatment process carburizing + tempering, because the high carbon content of the steel, and Si, Mn elements hydraulic drill rod material compared with Cr, Ni elements Especially in the case of high strength, ductility and its index is much lower than CrNiMo steel lines; such as carburizing isothermal quenching, the loss of surface hardness and compressive stress hollow steel, reducing the fatigue strength and wear resistance thread , it is difficult to improve the life of drill rod. So, from the 1960s to the mid-1980s, China's threaded drill rod (mainly length greater than 1 200 mm in size) can only be used in low-temperature heat treatment process quenching and tempering or austempering, which is the life of our country and abroad Threaded Rod Compared to the big gap between the main reason. 25CrNi3Mo conventional mechanical properties of steel and steel 35SiMnMoV Table 1. As can be seen from the data in Table 1 Drilling Rod hollow steel, air-cooled conditions under rock drill rod, toughness CrNi3Mo system is higher than SiMnMoV system, but the intensity is high. In the quenched state, strength and toughness during tempering CrNi3Mo Department, SiMnMoV line when you want to achieve or improve the tempering temperature isothermal hardening. If both after carburizing process to deal with according to Table 1, the threaded portion of the high surface hardness CrNi3Mo lines, high compressive stress, not only wearable but also improve the life; and SiMnMo Department elevated temperature or isothermal quenching and tempering, has decreased carburized threaded surface hardness, wear resistance and compressive residual stress, thereby shortening the service life. After the material is selected, heat threaded drill rod and ensure that the key is to improve the life of the drill rod. A heat treatment process abroad most foreign 25CrNi3Mo steel threaded drill rod selection, the overall gas carburizing process. The process have a large investment in deep gas carburizing furnace, which the carburized layer thickness, the surface carbon concentration, temperature carburizing, carburizing time, carburizing furnace atmosphere, cooling, etc., can be controlled by the microcomputer, so can guarantee to get a good quality and performance. After the whole carburizing, two thread re IF quenching and tempering to obtain high wear resistance threaded parts. Rod hardness is achieved by controlled cooling after carburizing overall. There are also some foreign manufacturers to choose low carbon CrNiMo Department of steel, quenched and tempered thread after two high-frequency quenching. Rod hardness is controlled at the time of the hollow steel rolling production to get the hardened layer thickness of the threaded portion of the general control of induction hardening 2.5 mm or less. Features abroad heat treatment process is: carburizing and induction hardening drill rod threaded surfaces can make to obtain high hardness and wear resistance, but also to obtain a high surface compressive stress. Surface compressive stress and lath martensite and austenite film-like structure within the slats can improve the surface fatigue strength, fatigue fracture threshold, reducing the fatigue crack propagation rate, which is to improve the life of the very thread Rod favorable. Hollow steel pipes | Drilling Ltd. Shandong Peng Rui (certified) | hollow steel drill by Shandong Peng Rui Technology Limited. Drilling Ltd. Shandong Peng Rui (www.zbpengrui.com) Shandong Zibo, metal cutting class leader, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Shandong Peng Rui Drilling Ltd. led the staff warmly welcome all inquiries negotiations to create Shandong Peng Rui Drilling Ltd. a better future.