Annealing method for high-speed steel cold-drawing wire products

Abstract

The invention discloses annealing method for high speed tool steel cold drawn steel wire finished products, solving the problems of low annealing efficiency, large energy consumption, etc. The mass percentage compositions of a high speed tool steel cold drawn steel wire rod are: 0.80 to 0.90 percent by mass of C, less than or equal to 0.40 percent by mass of Mn, less than or equal to 0.40 percent by mass of Si, 3.80 to 4.40 percent by mass of Cr, 1.75 to 2.20 percent by mass of V, 5.50 to 6.75 percent by mass of W, 4.50 to 5.50 percent by mass of Mo, less than or equal to 0.030 percent by mass of P, less than or equal to 0.030 percent by mass of S, and the balance Fe. The method comprises the following steps of: 1) annealing of finished product, in which the rod is placed into a strong-convection annealing furnace, a heating mantle is cover on the furnace, and then nitrogen purging is carried out to replace the air in the furnace with nitrogen which is used for atmosphere protection during the annealing process; 2) heating the product with the furnace to a temperature of between 710 and 750 DEG C and keeping the temperature for 4 to 8 hours, covering the heating mantle, and then cooling down the furnace to a temperature below 650 DEG C, at a cooling speed less than or equal to 30 DEG C per hour, and removing the heating mantle; 4) covering a cooling mantle to cool down the product to a temperature below 140 DEGC at a cooling speed more than 100 DEG C per hour. The invention is high in annealing efficiency, thereby greatly reducing the energy consumption.

Description

technical field [0001] The invention relates to heat treatment of metal materials, in particular to a finished annealing method of high-speed tool steel cold-drawn steel wire. Background technique [0002] High-speed tool steel such as W6Mo5Cr4V2 is a representative grade of high-speed tool steel. Because of its good red hardness, high-temperature hardness, toughness and wear resistance, high-speed steel wire is mainly used for high-speed cutting tools and drills. The main production process of high-speed tool steel cold-drawn steel wire is: hot-rolled annealing disc-pickling coating-drawing-intermediate annealing-pickling, coating-drawing (cycle intermediate annealing and drawing passes until the finished product ) - finished product annealing - straightening (grinding) - inspection and storage. Among them, finished product annealing is the last heat treatment in the production of high-speed tool steel cold-drawn steel wire. The purpose is to reduce the hardness to the ran...

AI Technical Summary

Problems solved by technology

[0004] The disadvantages of annealing high-speed tool steel cold-drawn wire finished products by adopting the above-mentioned existing rectangular bell furnace method are:

[0005] 1) Due to the slow heat transfer and heating speed of the barrel annealing method, in order to ensure the uniform annealing hardness of the finished product, three annealing processes are adopted according to different specifications: 750°C annealing process for ≥7mm finished products, 730°C for φ7~≥4mm finished products Annealing process, 710°C annealing process for finished products < 4mm, the process is more complicated, different specifications of materials must be annealed in separate furnaces, which affects the production progress to a certain extent

[0006] 2) The amount of furnace installed is too small, resulting in high energy consumption per ton of steel, and the average natural gas consumption per ton of steel reaches 298m 3 , far higher than the company's internal natural gas assessment index per ton of steel

[0007] 3) Since the high-speed tool steel wire drawing uses a high material rack, it needs to be turned over to the low material rack before annealing to load the barrels. Before and after annealing, barrels must be loaded and unloaded. The operation steps are cumbersome and the production very inefficient;

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