CN104195462A - An ultrahigh strength cast steel and a manufacturing method thereof - Google Patents

Abstract

The invention discloses an ultrahigh strength cast steel and a manufacturing method thereof. The cast steel contains the following chemical elements by mass percent: 0.04-0.06 % of carbon, 0.3-0.5 % of silicon, 0.04-0.06 % of manganese, 0.4-0.7 % of calcium, 0.003-0.004 % of cerium, 0.2-0.3 % of magnesium, 0.7-0.8 % of molybdenum, 0.023-0.026 % of boron, 0.18-0.23 % of niobium, 0.001-0.0032 % of titanium, <= 0.25 % of sulfur, 0.03-0.04 % of phosphorus and the balance of iron. Since molybdenum, boron, niobium and titanium alloy elements are added to the cast steel material of the invention, the steel has good strength, toughness and mechanical property. The production process of the invention has unique thermal treatment process, high production efficiency, energy conservation and environment protection and good economic benefits. Moreover, the production process is suitable for large scale production and has good promotion value.

Description

A kind of superhigh strength cast steel and manufacture method thereof

Technical field

The present invention relates to a kind of steel alloy and manufacture method thereof, particularly a kind of manufacture method of superhigh strength cast steel.

Background technology

The metal kit of automobile not only has higher requirement in structural strength and function, while no less important in mechanical workout, and such requirement is not only and is met the primary condition that automobile uses, and is also the safe and reliable guarantee increasing the service life simultaneously.

In prior art, the steel of producing auto parts machinery are common middle low levels steel alloy, and because these automobile metal accessories are generally moving partss frequently using in function, wear rate is very high, change frequently, have increased maintenance cost; Search out a kind of raising hardness and wear resisting property, it is extremely important that the steel alloy of the middle low levels that piece surface resistance toheat is high simultaneously just shows.

Summary of the invention

The object of the present invention is to provide a kind of manufacture method of superhigh strength cast steel.

The present invention adopts following technical scheme:

Superhigh strength cast steel, chemical element composition and mass percent thereof that it contains are: carbon 0.04-0.06%, silicon 0.3-0.5%, manganese 0.04-0.06%, calcium 0.4-0.7%, cerium 0.003-0.004%, magnesium 0.2-0.3%, molybdenum 0.7-0.8%, boron 0.023-0.026%, niobium 0.18-0.23%, titanium 0.001-0.0032%, sulphur≤0.25%, phosphorus 0.03-0.04%, surplus are iron.

The manufacture method of superhigh strength cast steel, comprises the following steps:

(1) ferrosilicon, ferromanganese and scrap iron are dropped in vacuum induction furnace and melted in 1:4-5:2.8-3.5 ratio, then add steel scrap, as ferrous substrate, originate; Carry out desulfurization, deoxidation; Then add successively molybdenum, boron, niobium and titanium alloy element alloyed, each described alloy adding is the 1/2-3/5 of mass percent separately in its formula, controlling pressure in induction furnace is 0.0003-0.0005Mpa, Heating temperature is to 1280-1420 ℃, hot rolling after melting, makes steel billet after cooling;

(2) steel billet of step (1) is put into electric arc furnace and be melted to molten state, be incubated 2-4h, then add wherein each alloying element of molybdenum, boron, niobium and titanium of residual content, stir, insulation 20-30 minute, then add wherein other residue alloying element, at 1430-1550 ℃ of refining 30-50min, after insulation 20-30min, sample, after analysis ingredient, adjusting component, fusing 15-20min, casting, tapping temperature is 1430-1480 ℃;

(3) profiled member in step (2) is forged, open forging temperature >=970 ℃, final forging temperature >=725 ℃, forging deformation amount >=22%, after forging, foundry goods is naturally cooled to 600-650 ℃, then by the method for liquid nitrogen gasification, foundry goods is carried out to deepfreeze, deepfreeze temperature is 0-50 ℃, deepfreeze soaking time be 30-50 minute last air-cooled to room temperature.

Beneficial effect of the present invention:

In cast steel material of the present invention, added molybdenum, boron, niobium and titanium alloy element, made steel there is good strength, toughness and mechanical property; Production technique of the present invention has unique thermal treatment process, and production efficiency is high, energy-conserving and environment-protective, good in economic efficiency, is suitable for scale operation, has good promotional value.

Embodiment

Embodiment 1: superhigh strength cast steel, chemical element composition and mass percent thereof that it contains are: carbon 0.05%, silicon 0.4%, manganese 0.05%, calcium 0.5%, cerium 0.0035%, magnesium 0.25%, molybdenum 0.75%, boron 0.025%, niobium 0.2%, titanium 0.002%, sulphur≤0.25%, phosphorus 0.035%, surplus are iron.

The manufacture method of superhigh strength cast steel, comprises the following steps:

(1) ferrosilicon, ferromanganese and scrap iron are dropped in vacuum induction furnace and melted in 1:4.5:3 ratio, then add steel scrap, as ferrous substrate, originate; Carry out desulfurization, deoxidation; Then add successively molybdenum, boron, niobium and titanium alloy element alloyed, each described alloy adding is in its formula separately 1/2 of mass percent, and controlling pressure in induction furnace is 0.0004Mpa, Heating temperature to 1350 ℃, hot rolling after melting, makes steel billet after cooling;

(2) steel billet of step (1) is put into electric arc furnace and be melted to molten state, be incubated 2-4h, then add wherein each alloying element of molybdenum, boron, niobium and titanium of residual content, stir, be incubated 25 minutes, then add wherein other residue alloying element, at 1540 ℃ of refining 40min, after insulation 25min, sample, after analysis ingredient, adjusting component, fusing 15-20min, casting, tapping temperature is 1430 ℃;

(3) profiled member in step (2) is forged, open forging temperature >=970 ℃, final forging temperature >=725 ℃, forging deformation amount >=22%, after forging, foundry goods is naturally cooled to 620 ℃, then by the method for liquid nitrogen gasification, foundry goods is carried out to deepfreeze, deepfreeze temperature is 0-50 ℃, deepfreeze soaking time be 40 minutes last air-cooled to room temperature.

The present invention manufacture cast steel testing data: tensile strength sigma b>=1230MPa; Yield strength σ 0.2>=1015MPa; Room temperature impelling strength α ku (42 ℃)>=77J/cm ²; Low-temperature impact toughness σ ku (40 ℃)>=33J/cm ²; Hardness HRC34-38.

Claims (2)

1. a superhigh strength cast steel, is characterized in that: chemical element composition and mass percent thereof that it contains are: carbon 0.04-0.06%, silicon 0.3-0.5%, manganese 0.04-0.06%, calcium 0.4-0.7%, cerium 0.003-0.004%, magnesium 0.2-0.3%, molybdenum 0.7-0.8%, boron 0.023-0.026%, niobium 0.18-0.23%, titanium 0.001-0.0032%, sulphur≤0.25%, phosphorus 0.03-0.04%, surplus are iron.

2. a manufacture method for superhigh strength cast steel as claimed in claim 1, is characterized in that comprising the following steps:

(1) ferrosilicon, ferromanganese and scrap iron are dropped in vacuum induction furnace and melted in 1:4-5:2.8-3.5 ratio, then add steel scrap, as ferrous substrate, originate; Carry out desulfurization, deoxidation; Then add successively molybdenum, boron, niobium and titanium alloy element alloyed, each described alloy adding is the 1/2-3/5 of mass percent separately in its formula, controlling pressure in induction furnace is 0.0003-0.0005Mpa, Heating temperature is to 1280-1420 ℃, hot rolling after melting, makes steel billet after cooling;

(2) steel billet of step (1) is put into electric arc furnace and be melted to molten state, be incubated 2-4h, then add wherein each alloying element of molybdenum, boron, niobium and titanium of residual content, stir, insulation 20-30 minute, then add wherein other residue alloying element, at 1430-1550 ℃ of refining 30-50min, after insulation 20-30min, sample, after analysis ingredient, adjusting component, fusing 15-20min, casting, tapping temperature is 1430-1480 ℃;

(3) profiled member in step (2) is forged, open forging temperature >=970 ℃, final forging temperature >=725 ℃, forging deformation amount >=22%, after forging, foundry goods is naturally cooled to 600-650 ℃, then by the method for liquid nitrogen gasification, foundry goods is carried out to deepfreeze, deepfreeze temperature is 0-50 ℃, deepfreeze soaking time be 30-50 minute last air-cooled to room temperature.