AISI4340 prestress steel bar manufacturing method

Abstract

The present invention discloses a AISI4340 prestress steel bar manufacturing method, wherein a AISI4340MOD steel is adopted as a billet material, the billet material is subjected to smelting and finish rolling to obtain a prestress steel bar forging stock with the required size, the prestress steel bar forging stock is sequentially subjected to a hydrogen diffusion heat treatment, rough processing, water cooling quenching and air cooling quenching, a polyethylene corrosion resistance coating is coated on the outer surface of the steel bar forging stock, and a polyethylene heat shrink sleeve is arranged outside the polyethylene corrosion resistance coating. According to the AISI4340 prestress steel bar manufacturing method designed by the present invention, the obtained AISI4340 prestress steel bar has characteristics of high strength, good ductility, strong delayed fracture resistance, steel saving, low relaxation, easy welding, good upsetting property and the like, and further has effects of substantially enhanced corrosion resistance sealing property, and effectively improved mechanical strength.

Description

technical field [0001] The invention relates to a method for manufacturing AISI4340 prestressed steel rods. Background technique [0002] In the prior art, the atomic activity of carbon and nitrogen elements in the raw material composition is low, and the air mass formed by each atom cannot form a strong interaction with the dislocation, and the dislocation can be activated without providing a large external stress, so that the performance It is very unstable, and at the same time, the hydrogen content in the steel bar forging blank is above 2.0ppm, and the steel bar forging blank is prone to cracks, thereby inducing hydrogen-induced cracks and hydrogen-induced delayed hysteresis cracks. [0003] In the prior art, only a single quenching method is generally used, so that the quenching cracking and internal cracking of the forging cannot be prevented. At the same time, the carbides cannot be further fully dissolved and cannot be uniformly diffused, so that the precipitation o...

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Problems solved by technology

[0002] In the prior art, the atomic activity of carbon and nitrogen elements in the raw material composition is low, and the air mass formed by each atom cannot form a strong interaction with the dislocation, and the dislocation can be activated without providing a large external stress, so that the performance Very unstable, and at the same time, the hydrogen content in the forging steel bar is above 2.0ppm, and the forging steel bar is prone to cracks, which induces hydrogen-induced cracks and hydrogen-induced delayed hysteresis cracks

[0003]In the prior art, only a single quenching method is generally used, so that the quenching cracking and internal cracking of the forging cannot be prevented, and the carbides cannot be further fully dissolved, and the uniformity cannot be achieved. Diffusion, so that the precipitation of carbides between grains cannot be avoided, resulting in excessive intergranular corrosion and pitting corrosion, which affects the technical effect of the heat treatment process after smelting.

[0004] Most of the prestressed steel bars produced by foreign companies do not have any insulating protective layer on the outside. The insulation between the prestressed steel bars in the track slab is realized by insulating fasteners. The insulation effect is not ideal. Although coating modified asphalt can improve the insulation and anticorrosion performance of prestressed steel bars, it will cause environmental pollution during the construction process.