CN104073742A

CN104073742A - Alloy steel material for air valve and preparation method thereof

Info

Publication number: CN104073742A
Application number: CN201410194588.9A
Authority: CN
Inventors: 肖颖
Original assignee: Tongling Mingcheng Casting Co Ltd
Current assignee: Tongling Mingcheng Casting Co Ltd
Priority date: 2014-05-09
Filing date: 2014-05-09
Publication date: 2014-10-01

Abstract

The invention discloses an alloy steel material for an air valve. The alloy steel material comprises chemical elementary components in percentage by mass: 0.3-0.5 percent of carbon, 0.2-0.25 percent of silicon, 23.0-24.5 percent of nickel, 0.4-0.5 percent of chromium, 0.005-0.008 percent of molybdenum, 0.004-0.008 percent of titanium, 0.03-0.05 percent of aluminum, 3.3-3.5 of manganese, 2.1-2.3 percent of copper, 0.04-0.05 percent of boron, less than or equal to 0.030 percent of P, less than or equal to 0.030 percent of S, and the balance of Fe. According to the alloy steel material, the raw materials of nickel, copper and the like are combined, the proportions and the production process are reasonably set, and the input order is reasonably set, so that the formed alloy material has the characteristics of high fuel corrosion resistance, high oxidization resistance, high high-temperature strength and high-temperature hardness and long service life, and is suitable for high-temperature parts which are easy to corrode like air valves; a part of waste iron is used as the raw material so that the quality of the alloy is stable and uniform; by using refining agents, pore degrees are reduced by 1-2 degrees.

Description

A kind of alloy steel material for air valve and preparation method thereof

Technical field

The present invention relates to metallic substance preparation field, relate in particular to a kind of alloy steel material for air valve and preparation method thereof.

Background technology

The development of steel alloy has had the history of more than 100 year, up to the present, diversified steel alloy is employed industrial, mainly contain with Types Below: quenched and tempered steel, spring steel, tool steel, rapid steel, die steel, high, normal, basic carbon alloy steel etc., so far, although steel alloy technology is greatly developed, but, still have a lot of problems to exist, as fastness to rubbing, hardness, rustless property, corrosion resistance nature, high and low temperature resistance, fragility, toughness, costs etc. can not be taken into account, in a lot of occasions, can't meet the requirement of production, also require further improvement, to enhance productivity, reduce costs, improve security, for high-quality precision and sophisticated technology development provides safeguard, for social development provides power, task is also very arduous.

Summary of the invention

The object of the present invention is to provide a kind of alloy steel material for air valve and preparation method thereof, this alloy material has high resistance to combustion gas corrosion, antioxidant property is good, and hot strength, hot hardness are high, the advantage of long service life.

Technical scheme of the present invention is as follows:

An alloy steel material for air valve, is characterized in that: chemical element composition and mass percent thereof that it contains are: carbon 0.3-0.5, silicon 0.2-0.25, nickel 23.0-24.5, chromium 0.4-0.5, molybdenum 0.005-0.008, titanium 0.004-0.008, aluminium 0.03-0.05, manganese 3.3-3.5, copper 2.1-2.3, boron 0.04-0.05, P≤0.030, S≤0.030, surplus are iron.

The production method of the described alloy steel material for air valve, is characterized in that:

(1), the pig iron and scrap iron are dropped in stove and melt and originate as ferrous substrate in 1:1 ratio; Carry out desulfurization, deoxidation, alloying, the refining of employing refining agent, casting, casting postheat treatment etc.;

(2) in alloying process, to the lot sequence that drops into alloying element in stove, be: (1) silicon, manganese, titanium; (2) nickel, chromium, molybdenum; (3) other remaining component; The timed interval that each batch drops into element is 12-15 minute, after feeding intake, stirs.

Described casting postheat treatment is: first by room temperature, with 200-230 ℃/h of speed, be warming up to 930-945 ℃, insulation 3-4 hour; With 140-160 ℃/h of speed, be cooled to 630-650 ℃ again, insulation 30-60 minute; With 100-120 ℃/h of speed, be cooled to 320-340 ℃ again, insulation 2-3 hour; With 150-170 ℃/h of speed, be warming up to 520-540 ℃ again, insulation 2-3 hour, takes out air cooling and get final product.

Described refining agent is made by the raw material of following weight part: instrument comminuted steel shot 3-4, clay 10-12, Wingdale 3-4, sepiolite 2-3, Sodium Silicofluoride 2-3, SODIUMNITRATE 1-2, vermiculite 5-6, silicon carbide 9-11, titanium dioxide 2-3, fluorite 6-8, aluminium hydroxide 8-10, jade powder 3-4, montmorillonite 1-2; Preparation method mixes each raw material, is heated to molten state and stirs remove slag, and then, is poured into Quench in pure water, then is ground into 100-200 order powder; Gained powder is added and is equivalent to the silane resin acceptor kh-550 of powder weight 2-3%, the nano-carbon powder of 1-2%, after mixing, under 8-15Mpa, be pressed into base, then, at 900-950 ℃, calcine 3-4 hour, cooling after, be ground into again 150-250 order powder, obtain.

Beneficial effect of the present invention

The present invention is by using the material combination such as nickel, copper, proportioning and production technique are rationally set, input order is rationally set, the alloy material forming has high resistance to combustion gas corrosion, antioxidant property is good, hot strength, hot hardness are high, the feature of long service life, is applicable to the perishable parts of the high temperature such as air valve; And use part scrap iron as raw material, make the steady quality homogeneous of alloy.Refining agent of the present invention is for Foundry Production, and the degree of porosity obviously improving in yield rate, particularly foundry goods reduces 1-2 degree, is controlled effectively, and can not produce pore at cast(ing) surface, and trapped oxide also obviously reduces, and oxide inclusion is 2 grades of left and right.

Embodiment

For an alloy steel material for air valve, chemical element composition and mass percent thereof that it contains are: carbon 0.3-0.5, silicon 0.2-0.25, nickel 23.0-24.5, chromium 0.4-0.5, molybdenum 0.005-0.008, titanium 0.004-0.008, aluminium 0.03-0.05, manganese 3.3-3.5, copper 2.1-2.3, boron 0.04-0.05, P≤0.030, S≤0.030, surplus are iron.

The production method of the described alloy steel material for air valve is:

(2) in alloying process, to the lot sequence that drops into alloying element in stove, be: (1) silicon, manganese, titanium; (2) nickel, chromium, molybdenum; (3) other remaining component; The timed interval that each batch drops into element is 13 minutes, after feeding intake, stirs.

Described casting postheat treatment is: first by room temperature, with 220 ℃/h of speed, be warming up to 940 ℃, be incubated 3.5 hours; With 150 ℃/h of speed, be cooled to 640 ℃ again, be incubated 50 minutes; With 110 ℃/h of speed, be cooled to 330 ℃ again, be incubated 2.5 hours; With 160 ℃/h of speed, be warming up to 530 ℃ again, be incubated 2 hours, take out air cooling and get final product.

Described refining agent by following weight part (kilogram) raw material make: instrument comminuted steel shot 4, clay 10, Wingdale 3, sepiolite 2, Sodium Silicofluoride 2, SODIUMNITRATE 2, vermiculite 5, silicon carbide 9, titanium dioxide 2, fluorite 8, aluminium hydroxide 8, jade powder 3, montmorillonite 2; Preparation method mixes each raw material, is heated to molten state and stirs remove slag, and then, is poured into Quench in pure water, then is ground into 100-200 order powder; Gained powder is added and is equivalent to the silane resin acceptor kh-550 of powder weight 2%, 1% nano-carbon powder, after mixing, under 12-15Mpa, be pressed into base, then, at 900-950 ℃, calcine 3-4 hour, cooling after, be ground into again 150-250 order powder, obtain.

The present invention for the mechanical property of the alloy steel material of air valve is: tensile strength 1350MPa, yield strength 973MPa, unit elongation 14%, relative reduction in area 23%, impact absorbing energy 53J, impelling strength 63J/cm2, hardness 295HB.

Claims

1. for an alloy steel material for air valve, it is characterized in that: chemical element composition and mass percent thereof that it contains are: carbon 0.3-0.5, silicon 0.2-0.25, nickel 23.0-24.5, chromium 0.4-0.5, molybdenum 0.005-0.008, titanium 0.004-0.008, aluminium 0.03-0.05, manganese 3.3-3.5, copper 2.1-2.3, boron 0.04-0.05, P≤0.030, S≤0.030, surplus are iron.

2. the production method of the alloy steel material for air valve according to claim 1, is characterized in that:

3. the production method of the alloy steel material for air valve according to claim 2, is characterized in that: described casting postheat treatment is: first by room temperature, with 200-230 ℃/h of speed, be warming up to 930-945 ℃, insulation 3-4 hour; With 140-160 ℃/h of speed, be cooled to 630-650 ℃ again, insulation 30-60 minute; With 100-120 ℃/h of speed, be cooled to 320-340 ℃ again, insulation 2-3 hour; With 150-170 ℃/h of speed, be warming up to 520-540 ℃ again, insulation 2-3 hour, takes out air cooling and get final product.

4. the production method of the alloy steel material for air valve according to claim 2, is characterized in that: described refining agent is made by the raw material of following weight part: instrument comminuted steel shot 3-4, clay 10-12, Wingdale 3-4, sepiolite 2-3, Sodium Silicofluoride 2-3, SODIUMNITRATE 1-2, vermiculite 5-6, silicon carbide 9-11, titanium dioxide 2-3, fluorite 6-8, aluminium hydroxide 8-10, jade powder 3-4, montmorillonite 1-2; Preparation method mixes each raw material, is heated to molten state and stirs remove slag, and then, is poured into Quench in pure water, then is ground into 100-200 order powder; Gained powder is added and is equivalent to the silane resin acceptor kh-550 of powder weight 2-3%, the nano-carbon powder of 1-2%, after mixing, under 8-15Mpa, be pressed into base, then, at 900-950 ℃, calcine 3-4 hour, cooling after, be ground into again 150-250 order powder, obtain.