A spheroidizing annealing process for ml40cr hot-rolled wire

Abstract

The invention discloses an ML40Cr hot-rolled wire rod spheroidizing annealing technology. The diameter of an ML40Cr hot-rolled wire rod is 18-25 mm. The technology comprises the steps that the ML40Crhot-rolled wire rod is heated to reach the temperature of 765+ / -2 DEG C in a furnace, heat preserving is conducted, the temperature is reduced to 710+ / -2 DEG C and then heat preserving is reserved, and the temperature of the wire rod is reduced to the room temperature. The technology has the advantages that the spheroidizing level of the wire rod can reach level 4 by a continuous spheroidizing annealing technology, repeated temperature increasing or decreasing is not needed, the time needed for a working procedure is effectively shortened, the production cost for reaching the same spheroidizing level is greatly reduced, and the benefits of an enterprise are improved.

Description

technical field [0001] The invention relates to the technical field of heat treatment of wire rods, in particular to a spheroidizing annealing process for ML40Cr hot-rolled wire rods. Background technique [0002] In the preparation process of special steel, an annealing process is required before processing to make the properties of the steel meet the machinable requirements. If the annealing process is not adopted, the processing of the steel is more difficult, and the mold for steel processing is easily damaged, resulting in serious material damage. waste. In the large-scale (usually 18-25mm) ML40Cr metal wire rod, the hot-rolled wire rod is directly annealed by spheroidization (the spheroidization grade is 3 or below, and the metallographic diagram of this process is as follows: image 3 As shown), the drawing process, this method cannot meet the requirements of subsequent cold heading processing, and is prone to cold heading cracking, resulting in waste of hot-rolled wi...

AI Technical Summary

Problems solved by technology

[0002] In the preparation process of special steel, an annealing process is required before processing to make the properties of the steel meet the machinable requirements. If the annealing process is not adopted, the processing of the steel is more difficult, and the mold for steel processing is easily damaged, resulting in serious material damage. waste of

In the large-scale (usually 18-25mm) ML40Cr metal wire rod, the hot-rolled wire rod is directly annealed by spheroidization (the spheroidization grade is 3 or below, and the metallographic diagram of this process is as follows: image 3 As shown), the drawing process, this method cannot meet the requirements of subsequent cold heading processing, and is prone to cold heading cracking, resulting in waste of hot-rolled wire rods and the disadvantages of poor quality of finished products; The process of spheroidizing annealing and drawing, this kind of annealing processing method of secondary furnace can make the spheroidized structure reach level 4 and above, but the production cost is significantly increased, the production cycle is lengthened, and it is necessary to increase the temperature to the annealing temperature once Then reduce the processing temperature to room temperature, which seriously affects the production efficiency and benefit;

Images