Cr-containing steel for wire line core drilling and manufacturing method thereof

Abstract

The invention discloses Cr-containing steel for wire line core drilling and a manufacturing method thereof, and the manufacturing method is characterized by controlling the content of C, Si, Mn, Cr, Mo, V, Ti and Cu reasonably, using nitrogen in the steel effectively, depending on precipitation strengthening of V and Ti, adopting an appropriate deoxidization method, enhancing the toughness and guaranteeing the purity of the steel at the same time of refining grains, adopting the heat treatment process of tempering after rolling and utilizing bainite as the main structure, which enables the steel to have the performance of resisting cracks and delaying crackling. The yield strength of the steel is greater than 740MPa, the tensile strength is greater than 880MPa, the elongation rate is greater than 13 percent, the performance meets the use requirements of DZ75 steel grade, the steel has the production advantage of saving procedures and the cost advantage of saving energy, the mechanical property at room temperature is superior to that of steel that does not contain Cr, and the comprehensive properties of the product can compete with the comprehensive properties of imported products of the same steel grade, therefore, the product has good application prospect.

Description

technical field [0001] The invention relates to a manufacturing method of steel for rope coring in geological drilling. In particular, it relates to a kind of inner pipe for carrying out cores in wireline coring drilling tools when carrying out geological exploration at medium-deep positions below 1000 meters. The chemical composition and manufacturing method of seamless steel pipes for performance requirements. Background technique [0002] Wireline core drilling technology is used in geological core drilling and is an important means of proving underground resources. In 1987, South Africa used a diamond rope to get a core hole as deep as 5,424 meters. my country began to apply it to geological exploration drilling on the surface and in pits in the mid-1970s. At present, the maximum hole depth is 2,505 meters. [0003] Because the depth of most of the developed mines in China is less than 500 meters, the cold-drawn DZ60 drill pipe is mainly used from the beginning of wire...

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Problems solved by technology

[0007] Although, the standards involved in DZ75 steel pipes include YB 528-65, YB / T5050-93, GB3423-82, GB / T9808-2008, JIS G3465-1977, JIS G3465-1988, JIS G3465-2006; There is no clear and unique regulation on the material and heat treatment system, only performance requirements: yield strength greater than 740MPa, tensile strength greater than 880MPa, elongation greater than 10%

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