Gas shielded welding alloy welding wire steel wire rod and production method thereof

Abstract

The invention provides a gas shielded welding alloy welding wire steel wire rod and a production method thereof. The gas shielded welding alloy welding wire steel wire rod comprises, by weight, 0.06%-0.10% of C, 0.55%-0.70% of Si, 1.60%-1.75% of Mn, smaller than or equal to 0.010% of P, smaller than or equal to 0.008% of S, smaller than or equal to 0.10% of Cr, 0.85%-0.95% of Ni, smaller than or equal to 0.15% of Cu, 0.35%-0.45% of Mo, 0.08%-0.12% of Ti and the balance Fe and inevitable impurities. According to the method, molten steel smelted and refined through a converter is subjected to continuous casting, and the continuous casting superheat degree is smaller than or equal to 25 DEG C; the current intensity of electromagnetic stirring at the head end of the crystallizer is 300-400 A, the frequency of electromagnetic stirring at the head end of the crystallizer is 3-4 Hz, and the current intensity of electromagnetic stirring at the tail end of the crystallizer is 250-300 A, and the frequency of electromagnetic stirring at the tail end of the crystallizer is 8-10 Hz; a continuous rolling technology is adopted for a square billet obtained after continuous casting, the temperature range of a soaking zone in the rolling process is 1100-1160 DEG C, the initial rolling temperature of rolling is 960-1080 DEG C, and the final rolling temperature is 850-1000 DEG C; and controlling cooling to enable the spinning temperature to be 820-850 DEG C, enabling the temperature to be 460-570 DEG C when the alloy wire is taken out of a heat preservation cover, and collecting coils at 320-400 DEG C to obtain the alloy welding wire steel. According to the method, the proportion of abnormal structures of the special welding wire steel can be reduced, the obtained wire rod for the gas shielded welding wire is few in abnormal structures, and drawing machining is facilitated.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a gas shielded welding alloy welding wire steel wire rod and a production method thereof. Background technique [0002] Gas shielded welding wire can obtain excellent mechanical properties and process properties in a variety of shielding gas atmospheres. It is mainly used in the welding of key load-bearing components such as construction machinery, crane booms, and coal mine hydraulic supports. [0003] Welding wire steel belongs to slow cooling steel, and it is very easy to produce abnormal structure, such as upper bainite or martensite, in the production process of welding wire steel. The shape of upper bainite is feathery, which is the transformation product of the region with high bainite transformation temperature. The formation temperature of upper bainite is relatively high, and the ferrite strips and carbides in it are coarse, and its plastic deformation r...

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Problems solved by technology

The cementite in the upper bainite is distributed between the ferrite strips in the form of discontinuous short rods. The distribution of ferrite and cementite has obvious directionality, and there are also low carbon content and supersaturation Small defects with low dislocation density make the impact toughness of ferrite strips poor, which is easy to cause brittle fracture of welding wire steel

Martensite is a supersaturated solid solution of carbon dissolved in α-Fe. It is a metastable phase transformed by austenite through non-diffusion phase transformation. Its specific volume is larger than that of austenite, pearlite and other organizations. Although it has a high Strength and hardness, but the brittleness of martensite is very high, which can easily lead to brittle fracture of welding wire steel

[0004] Moreover, a large number of microcracks will be generated between the hard phase structure in upper bainite and martensite and the matrix. Larger tension will be generated during plastic flow around the tensite structure, which will lead to the fracture of the connection between the matrix and the martensite or upper bainite interface

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