A method for equidistant spiral rolling of large size 45 steel ultrafine grain bar

Abstract

The invention relates to the technical field of machining, in particular to an equidistant screw rolling method for a large-size 45 steel superfine crystal bar. The method comprises the following steps that S1, a 45 steel billet with the diameter D of 40-150 mm and the length of 300-5,000 mm is selected; S2, the 45 steel billet is put into a heating furnace and heated to 860-1,000 DEG C; S3, the heated 45 steel billet is transferred from the heating furnace to a guide chute of a skew rolling mill for 5-20 s; S4, feeding is carried out in the guide chute of the skew rolling mill, and the 45 steel billet is spirally moved in a deformation zone until the deformation is finished; and S5, the second step, the third step and the fourth step are repeated, 2-12 times of screw rolling is carried out on the 45 steel bar, and the 45 steel whole superfine crystal bar is obtained. The equidistant screw rolling method has the beneficial effects that the deformation zone has large penetration depth,and the bar diameter before and after oblique rolling remains unchanged and can be repeatedly rolled for multiple passes; and through the pressing-twisting combined three-dimensional severe deformation, the ideal grain refinement effect can be obtained.

Description

technical field [0001] The invention relates to the technical field of mechanical processing, in particular to an equidistant spiral rolling method for large-size 45 steel ultra-fine-grained rods. Background technique [0002] Ultrafine crystal / nanocrystalline materials are one of the hot topics in current material science research. Compared with traditional coarse-grained metal materials, ultra-fine-grained / nanomaterials show more excellent or unique properties in some aspects, such as higher strength and hardness, better fatigue performance and superplasticity, better Corrosion resistance, wear resistance and biological characteristics, etc. These excellent properties make ultra-fine-grained materials have broad application prospects in engineering fields such as aviation, aerospace, automobiles, marine, and biology, and also make people pay more attention to the development of ultra-fine-grained / nano-prepared technologies. In the usual fine-grain scale range, the mechan...

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Problems solved by technology

[0008] (3) Cumulative stacking rolling method: stack the original plates in double layers after surface treatment, roll and weld them together after heating, then cut them from the middle and send them back to the surface treatment before the next rolling and welding cycle, in order to ensure The plates can be welded together, and the reduction in each pass must not be less than 50%, but the ARB process requires strong shear stress conditions, and lubricants cannot be used, which is detrimental to the service life of the rolls

However, limited by the impact of the forming load, the cross-sectional dimensions of the rods obtained by this method are all within the range of 10x10mm, and the cross-sectional dimensions are small, so large-scale industrial applications cannot be realized, and the existing patents or papers mentioned Alloy steel ultra-fine-grained technology mostly adopts strip rolling with small deformation zone and poor penetrability, or produces small-sized uniform ultra-fine-grained blanks under extremely high loads, such as equal-diameter angular extrusion ( ECAP)

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