Heat treatment method of promoting precipitation of nano-scale carbide in W-containing alloy steel

Abstract

The invention relates to a heat treatment method of promoting precipitation of nano-scale carbide in W-containing alloy steel. The heat treatment method is charaterized by comprising the following steps of soaking a steel billet for 24-48h under the condition with the temperature being 1100-1200 DEG C, and performing cooling along with a furnace to a room temperature; performing austenitizing for20-40min under the condition with the temperature being 850-1000 DEG C, and performing quenching in ice salt water; performing heating to 650-750 DEG C under the condition with the vacuum degree being10<-3>-10<-2>Pa and the magnetic field intensity being 10-14T and at a speed of 3-7 DEG C / min, keeping isothermy for 0.5-3.0h, and cooling to the room temperature, wherein the steel billet is prepared from the following chemical components: 0.06-0.14wt% of C, 1.50-3.00wt% of W, smaller than 0.01wt% of P, smaller than 0.005wt% of S and the balance of Fe and inevitable impurities, and the temperature of the ice salt water is 3 DEG C below zero to 1 DEG C below zero. The heat treatment method provided by the invention is simple in technology, low in cost and short in production period; and the strength of the W-containing alloy steel subjected to treatment with the method is obviously improved.

Description

technical field [0001] The invention belongs to the technical field of carbide precipitation in W-containing alloy steel. In particular, it relates to a heat treatment method for promoting the precipitation of nano-carbides in W-containing alloy steel. Background technique [0002] Ultra-high-strength steel is a steel material with ultra-high strength, high plasticity and good toughness obtained through alloying, heat treatment and cold and hot processing on the basis of alloy structural steel, which can significantly increase strength while maintaining good plasticity and toughness , its tensile strength ≥ 1500MPa (or yield strength ≥ 1380MPa). With the substantial improvement in the research level of steel materials, ultra-high-strength steel has become an important class of steel materials that are widely used, such as aircraft landing gear and tail shafts, bulletproof steel plates for armored vehicles, bogies for large machinery, and rocket engines. Some special fields...

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Problems solved by technology

Scientific and technological personnel have done a lot of research and development work, such as: "A 900MPa grade hot-rolled nano-precipitation strengthened high-strength and high-toughness steel and its manufacturing method" (CN108004475A) patent technology, the patent technology is added by adding Nb, Ti, Mo, V, etc. The microstructure of precious alloying elements is bainite + nano-scale carbide, and the 900MPa hot-rolled nano-precipitation strengthened high-strength and high-toughness steel is produced, but the alloy composition is complex, the cost is high, and the heat treatment process is complicated

Another example is the patented technology of "precipitation-strengthened martensitic steel and its manufacturing method" (CN104271787A), in which high content of Ni (7.5-11.0%), Cr (10.5-13.5%), Mo (1.75- 2.5%) and other alloying elements, this type of steel also achieves good performance through the precipitation of second-phase particles, which increases the strength, but too many alloying elements are added, so the cost is high, and the heat treatment time is as long as several hours. Low

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