CN106555125A - For the austenitic heat-resistance steel and its smelting process of industrial furnace - Google Patents

Abstract

The invention discloses a kind of austenitic heat-resistance steel and its smelting process for industrial furnace：Its chemical composition（Mass percent）For：C：0.05%；Cr：0.08%；Ti：1.50%；Al：10%；W：1.50%；Nb：1.0%；Mo：1.8%；Ce：1.20%；V：1.20%；Remaining is Fe and impurity.In addition, on the basis of can filling a prescription more than, rare earth element is added：0.04%.

Description

For the austenitic heat-resistance steel and its smelting process of industrial furnace

Technical field

The invention belongs to technical field of metal, more particularly to a kind of austenitic heat-resistance steel and its smelting process for industrial furnace.

Background technology

Heat resisting steel is the steel alloy at high temperature with higher intensity and good chemical stability.The parts that heat resisting steel is worked in being widely used the industrial departments such as manufacture boiler, steam turbine, dynamic power machine, industrial furnace and aviation, petroleum and petrochemical industry at high temperature.Austenitic heat-resistance steel is because cheap be easy to smelt, and which has preferable corrosion resistance, is therefore particularly suitable for the manufacture of the industrial furnace part with complicated adverse circumstances.

Traditional metal material compared with austenitic heat-resistance steel, has following deficiency：1 traditional metal materials corrosion resistance at high temperature is poor, it is impossible to meet the requirement of industrial furnace；2 traditional metal materials are oxidized easily under industrial furnace high-temperature environment, cause the service life of parts to greatly reduce；The machinability and weldability of 3 traditional metal materials is bad, is not easy to the processing and manufacturing of industrial furnace part；The cost of 4 traditional metal materials is more expensive, and smelting process is complicated.

Chinese patent 201310667633.3, a kind of entitled Novel austenitic heat-resistance steel, a kind of austenite-series heat-resistant steel with the anti-steam corrosion of high temperature and good elevated temperature strength of the Invention Announce.Its chemical composition（Mass percent）For：C:0.02～0.10%；Si ：0.05～1.00%；Mn:0.4～2.0%；Cr:20～28%；Ni：30～39%；Nb:0.9～2.0%；Ti:1.6～2.8%；Al:0.9～2.0%；Cu:0.05～3. 50 %；C o:0.1～3.0 %；V:0.08～0 .80%；Zr:0.01～0.30%；C e：0.003～0.200%；B:0.001～0.010%；Remaining is Fe and impurity.In addition, on the basis of can filling a prescription more than, W is added:1.5～3.0%；Mg:0.001～0.010%.Its deficiency is easily environment to be adversely affected as its constituent contains heavy metal.

Chinese patent 201410339732.3, entitled austenitic heat-resistance steel and preparation method thereof, disclosure of the invention austenitic heat-resistance steel and preparation method thereof, wherein, the preparation method of austenitic heat-resistance steel comprises the steps：S1. weigh each material；S2. each material is heated and is refined；S3. stand cooling, add end-deoxidizer, and be poured in ingot mould, it is to be solidified after, abjection；S4. solution treatment and Ageing Treatment.The austenitic heat-resistance steel of the invention in preparation process, after solution treatment and Ageing Treatment so that austenite grain boundary separates out Laves phases Fe2Nb of continuous Laves phases and transgranular precipitation strip.Laves phases Fe₂Nb is mutually continuously separated out as precipitation strength, can effectively improve the creep rupture strength of material.Its deficiency is as preparation process complicated difficult is extensively to apply on a large scale.

The content of the invention

In view of the shortcomings of the prior art, the present invention seeks to provide a kind of austenitic heat-resistance steel and its smelting process for industrial furnace, it is to realize above-mentioned purpose of the invention, the present invention is adopted the following technical scheme that：

Various elements are had opposite impacts on to the performance of austenitic heat-resistance steel.Impact of the iron-aluminum-manganese to the described austenite heat-resistance Steel Properties for industrial furnace is analyzed first.Aluminium element can improve the anti-oxidant and anti-carburizing energy of the described austenitic heat-resistance steel for industrial furnace, and carbon and manganese are combined with each other and can be used to expand phase region and stable austenite.Carbon, aluminium, the appropriate cooperation of manganese, austenite can be obtained or containing a small amount of ferritic austenite-ferrite tissue, if the mass percent of carbon is more than 0.85% in steel, in ferro-aluminium-manganese steel, discontinuous precipitation, concurrent first portion perlitic transformation can occur in crystal boundary, so that steel is brittle, therefore certain restriction to be carried out to the carbon content of steel.To the non-oxidizability of steel not, if the quality of manganese is burned reduces 5%-6%, can play increases the antioxidation of aluminium mass fraction 1% to manganese element, therefore manganese content can carry out appropriate reduction.When rare earth element mass fraction is less than 0.1%, non-oxidizability and molten steel flow can be improved, improve surface quality of continuous castings, reduce hot cracking tendency.

Generally the heating-up temperature of industrial furnace is maintained at less than 900, is the single austenite of activity, to keep higher high-temperature temperature, the lower limit of aluminium element to be typically chosen in 7% or so.Its microscopic structure is the ferritic austenite-ferrite tissue containing volume fraction less than 25%.Simultaneously because iron, the elements such as aluminium, manganese have very big impact to the metallurgy and foundry quality of the described heat resisting steel for industrial furnace, therefore will reduce the inclusion content in steel in smelting process as far as possible, the secondary oxidation of the element such as aluminium in casting cycle is prevented, and will strictly control cast temperature.Increasing containing manganese and aluminum content for the described heat resisting steel for industrial furnace is that the linear expansion coefficient increase of steel is also easy to produce crackle when cooling down after casting.

Chromium, nickel element can greatly improve the operating temperature of the described heat resisting steel for industrial furnace.One in order to improve the oxidation resistance of steel, and in steel, chromium can be added to 30%, silicon：2%.To improve the elevated temperature strength of the heat resisting steel for industrial furnace, solution strengthening element cobalt and carbide tungsten, molybdenum, niobium etc. are added.In order to improve the mobility of molten steel, carbon content can be properly increased to 0.3%-0.5%.To improve the performance of foundry goods, using 1100-1150 solution treatment, carbide dissolution is made, eliminate ferrite, obtain uniform austenite structure, improve the non-oxidizability and high temperature creep strength of steel.

Titanium elements have a great impact to the performance of the described heat resisting steel for industrial furnace.The alloying element titanium and aluminium energy precipitating metal part compound phase in austenitic heat-resistance steel ag(e)ing process is main precipitation phase.Lattice constant is close with austenitic matrix, the two slightly difference, when mutually separating out, coherence can be formed, produce precipitation strength, but the content of phase only up to reach 20% or so, therefore too high titanium elements content is easily caused the reduction of austenitic matrix stability on the contrary, so that the penalty of austenitic heat-resistance steel.

A kind of chemical composition of the austenitic heat-resistance steel for industrial furnace（Mass percent）For：C:0.02～0.10%；Cr ：0.05～1.00%；Ti:0.6～2.0%；Al:7～15%；W：1.20～2.50%；Nb:0.9～2.0%；Mo:1.6～2.8%；Ce:0.9～2.0%；V:0.05～3.50 %；Remaining is Fe and impurity.In addition, on the basis of can filling a prescription more than, rare earth element is added：0.02～0.08 %.

Using a kind of smelting process of described austenitic heat-resistance steel for industrial furnace, comprise the steps：

Step 1：Various elements are mixed according to a kind of mass percent of the austenitic heat-resistance steel for industrial furnace, be then placed in induction furnace, preparing melting.

Step 2：Raw material is carried out into melting 1-2h in induction furnace, qualified molten steel can be obtained.

Step 2-1：Being initially powered up the power in 6-18min with about 40-60% carries out melting, when sensing in-furnace temperature rises to tend towards stability, power is gradually increased to maximum.

Step 2-2：After most of melting sources in induction furnace, slag former is added, slag making process is carried out to melting raw material, while the raw material extracted after fraction fusing is analyzed chemical examination.

Further, the slag former typically selects lime stone.

Further, according to the 1.0-2.0% addition slag formers of material quality fraction.

Step 2-3：The result of analytical test according to step 2-2, is finely adjusted to the material composition after fusing in 10-20min before melting terminates.

Step 3：Resulting molten steel is sent in vacuum drying oven and is cooled down, the vacuum in vacuum drying oven will be maintained at 0-1.2Pa, about cool down 10-15min.

Step 4：The molten steel higher than fusing point that step 3 is obtained is put in given model and is molded, after about 2-4h, molten steel gradually cooled and solidified into steel ingot.

Specific embodiment

Embodiment 1：

A kind of chemical composition of the austenitic heat-resistance steel for industrial furnace（Mass percent）For：C:0.05%；Cr ：0.08%；Ti:1.50%；Al:10%；W：1.50%；Nb:1.0%；Mo:1.8%；Ce:1.20%；V:1.20% ；Remaining is Fe and impurity.In addition, on the basis of can filling a prescription more than, rare earth element is added：0.04%.

Using a kind of smelting process of described austenitic heat-resistance steel for industrial furnace, comprise the steps：

Step 1：Various elements are mixed according to a kind of mass percent of the austenitic heat-resistance steel for industrial furnace, be then placed in induction furnace, preparing melting.

Step 2：Raw material is carried out into melting 1.5h in induction furnace, qualified molten steel can be obtained.

Step 2-1：Being initially powered up the power in 12min with about 50% carries out melting, when sensing in-furnace temperature rises to tend towards stability, power is gradually increased to maximum.

Step 2-2：After most of melting sources in induction furnace, slag former is added, slag making process is carried out to melting raw material, while the raw material extracted after fraction fusing is analyzed chemical examination.

Further, the slag former typically selects lime stone.

Further, according to 1.2% addition slag former of material quality fraction.

Step 2-3：The result of analytical test according to step 2-2, before melting terminates, 12min is finely adjusted to the material composition after fusing.

Step 3：Resulting molten steel is sent in vacuum drying oven and is cooled down, the vacuum in vacuum drying oven will be maintained at 1.1Pa, about cool down 15min.

Step 4：The molten steel higher than fusing point that step 3 is obtained is put in given model and is molded, after about 3h, molten steel gradually cooled and solidified into steel ingot.

Embodiment 2：

A kind of chemical composition of the austenitic heat-resistance steel for industrial furnace（Mass percent）For：C:0.08 %；Cr ：1.00%；Ti:1.5%；Al:12.0%；W：2.20%；Nb:1.5%；Mo:2.20%；Ce:1.80%；V:3.10% ；Remaining is Fe and impurity.In addition, on the basis of can filling a prescription more than, rare earth element is added：0.05%.

Using a kind of smelting process of described austenitic heat-resistance steel for industrial furnace, comprise the steps：

Step 1：Various elements are mixed according to a kind of mass percent of the austenitic heat-resistance steel for industrial furnace, be then placed in induction furnace, preparing melting.

Step 2：Raw material is carried out into melting 2h in induction furnace, qualified molten steel can be obtained.

Step 2-1：Being initially powered up the power in 15min with about 45% carries out melting, when sensing in-furnace temperature rises to tend towards stability, power is gradually increased to maximum.

Step 2-2：After most of melting sources in induction furnace, slag former is added, slag making process is carried out to melting raw material, while the raw material extracted after fraction fusing is analyzed chemical examination.

Further, the slag former typically selects lime stone.

Further, according to 1.2% addition slag former of material quality fraction.

Step 2-3：The result of analytical test according to step 2-2, is finely adjusted to the material composition after fusing during 20min before melting terminates.

Step 3：Resulting molten steel is sent in vacuum drying oven and is cooled down, the vacuum in vacuum drying oven will be maintained at 0.9Pa, about cool down 15min.

Step 4：The molten steel higher than fusing point that step 3 is obtained is put in given model and is molded, after about 3.5h, molten steel gradually cooled and solidified into steel ingot.

Claims (2)

1. the chemical composition of the austenitic heat-resistance steel of industrial furnace is used for（Mass percent）For：C:0.02～0.10%；Cr ：0.05～1.00%；Ti:0.6～2.0%；Al:7～15%；W：1.20～2.50%；Nb:0.9～2.0%；Mo:1.6～2.8%；Ce:0.9～2.0%；V:0.05～3.50 %；Remaining is Fe and impurity；

In addition, on the basis of can filling a prescription more than, rare earth element is added：0.02～0.08 %.

2. a kind of described austenitic heat-resistance steel and its smelting process for industrial furnace is adopted, is comprised the steps：

Step 1：Various elements are mixed according to a kind of mass percent of the austenitic heat-resistance steel for industrial furnace, be then placed in induction furnace, preparing melting；

Step 2：Raw material is carried out into melting 1-2h in induction furnace, qualified molten steel can be obtained；

Step 2-1：Being initially powered up the power in 6-18min with about 40-60% carries out melting, when sensing in-furnace temperature rises to tend towards stability, power is gradually increased to maximum；

Step 2-2：After most of melting sources in induction furnace, slag former is added, slag making process is carried out to melting raw material, while the raw material extracted after fraction fusing is analyzed chemical examination；

Further, the slag former typically selects lime stone；

Further, according to the 1.0-2.0% addition slag formers of material quality fraction；

Step 2-3：The result of analytical test according to step 2-2, is finely adjusted to the material composition after fusing in 10-20min before melting terminates；

Step 3：Resulting molten steel is sent in vacuum drying oven and is cooled down, the vacuum in vacuum drying oven will be maintained at 0-1.2Pa, about cool down 10-15min；

Step 4：The molten steel higher than fusing point that step 3 is obtained is put in given model and is molded, after about 2-4h, molten steel gradually cooled and solidified into steel ingot.