Heat treatment method for improving bending fatigue strength of thick wet-drawn steel wire

Abstract

The invention relates to a heat treatment method for improving bending fatigue strength of a thick wet-drawn steel wire. The heat treatment method comprises the following specific steps that a, heating is conducted, specifically, an advancing raw material steel wire with a diameter of 2.0 mm to 3.2 mm is heated by adopting a heating furnace, an advancing speed of the raw material steel wire is 20 m / min to 50 m / min, a heating temperature is 900 DEG C to 1000 DEG C, and heating time is 30 s to 100 s, so that the raw material steel wire is completely austenitized; b, water quenching is conducted, specifically, the raw material steel wire is led into a water cooling tank with a temperature of 90 + / - 5 DEG C to be subjected to water bath after being discharged out of the furnace, a water bath length is 200 cm to 300 cm, water bath cooling time is 2.4 s to 9 s, a water outlet temperature of the raw material steel wire is 500 DEG C to 550 DEG C, and the raw material steel wire is converted from austenite to sorbite; c, air cooling is conducted, specifically, air cooling is conducted on the discharged raw material steel wire, and a highest return temperature of air cooling does not exceed 600 DEG C; d, electroplating is conducted, specifically, the drawn and air-cooled raw material steel wire is electroplated by means of an electroplating pool to form a plating layer on a surface layer of the steel wire; and e, wet drawing is conducted, specifically, wet drawing is conducted on the electroplated raw material steel wire, and the steel wire with a thick specification of 0.4 mm or more is produced.

Description

technical field [0001] The invention relates to a heat treatment method for improving the bending fatigue strength of thick-gauge wet-drawn steel wire. Background technique [0002] At present, the wet-drawn steel wire with a thick specification of 0.4mm and above is made of semi-finished electroplated wire with a specification above 2.0mm as raw material, and the production of semi-finished electroplated wire needs to go through heat treatment and electroplating process, and the water bath cooling in the heat treatment process generally adopts two In the segmental water cooling process, due to the thicker raw material steel wire, during the heat treatment process, the temperature difference between the inside and the outside of the steel wire is large when cooling, resulting in poor metallographic structure uniformity and uneven hardness distribution of the steel wire during heat treatment, with low surface hardness and core hardness. Higher, resulting in lower bending perf...

AI Technical Summary

Problems solved by technology

[0002] At present, the wet-drawn steel wire with a thick specification of 0.4mm and above is made of semi-finished electroplated wire with a specification above 2.0mm as raw material, and the production of semi-finished electroplated wire needs to go through heat treatment and electroplating process, and the water bath cooling in the heat treatment process generally adopts two In the segmental water cooling process, due to the thicker raw material steel wire, during the heat treatment process, the temperature difference between the inside and the outside of the steel wire is large when cooling, resulting in poor metallographic structure uniformity and uneven hardness distribution of the steel wire during heat treatment, with low surface hardness and core hardness. Too high, resulting in low bending performance of the final coarse-gauge wet-drawn steel wire