Titanium-containing cold heading steel wire rod for 12.9-grade fastener and production method for titanium-containing cold heading steel wire rod

Abstract

The invention discloses a titanium-containing cold heading steel wire rod for a 12.9-grade fastener and a production method for the titanium-containing cold heading steel wire rod. The wire rod comprises the following components in percentage by weight: 0.34 to 0.38 percent of C, 0.15 to 0.30 percent of Si, 0.60 to 0.90 percent of Mn, less than or equal to 0.020 percent of P, less than or equal to 0.020 percent of S, 0.90 to 1.10 percent of Cr, 0.17 to 0.24 percent of Mo, 0.005 to 0.05 percent of Ti, 0.01 to 0.04 percent of Al and 40 to 110ppm of N, which are basic components, more than one of 5 to 30ppm of B, 5 to 20ppm of Ca and 0.05 to 0.20 percent of Cu, which is optional components, and the balance of iron and impurities. The preparation method sequentially comprises the following steps of: smelting in an electric furnace; refining outside the furnace; continuously casting small square billets; polishing the square billets; and performing high-speed wire controlled rolling; cooling large-roll coiled wires in piles or Stelmor wire controlled cooling, and the preparation method also can comprise a step of performing vacuum treatment after the step of refining outside the furnace. The titanium-containing cold heading steel wire rod completely meets the production and use requirements of the 12.9-grade fastener, has the advantages of simple production process, low cost, low energy consumption, low carbon emission and light environmental pollution and meets the long-term requirements of low-carbon economy and sustainable development.

Description

Technical field [0001] The invention relates to a cold heading steel wire rod and a preparation process thereof, in particular to a titanium-containing cold heading steel wire rod for 12.9-grade fasteners and a production method thereof, and belongs to the field of steel metallurgy and steel rolling. Background technique [0002] Fasteners are a general term for a type of mechanical parts used when two or more parts (or components) are fastened and connected into a whole, including bolts, screws, nuts, studs, rivets, etc., are widely used Automobiles, machinery, ships, railways, bridges, construction, electronics and other fields. Cold heading steel is the main raw material for the production of fasteners. my country is a major producer of cold-heading steel, accounting for more than 35% of the world’s output. However, domestically-made cold-heading steel is generally of low grade, mainly for fasteners of grade 8.8 and below. High-end products such as automobiles, aviation, hig...

AI Technical Summary

Problems solved by technology

However, compared with converter steelmaking, the nitrogen content of electric furnace steelmaking is not easy to control. If no measures are taken, the free nitrogen in the steel will cause strain aging during the cold heading process, resulting in wire drawing fracture and cold heading cracking of the workpiece.