CN102492892A

CN102492892A - Cast iron for making pig mold

Info

Publication number: CN102492892A
Application number: CN2011104441669A
Authority: CN
Inventors: 纪汉成; 沈火元; 陆文俊
Original assignee: BENXI XIN XINGSHENG CASTING CO LTD
Current assignee: BENXI XIN XINGSHENG CASTING CO LTD
Priority date: 2011-12-27
Filing date: 2011-12-27
Publication date: 2012-06-13

Abstract

The invention relates to a cast iron for making pig mold. The cast iron contains carbon, silicon, manganese, chromium and rare earth element. With the addition of rare earth metal in the cast iron, the microstructure of the cast iron is compact, graphite is refined, and mechanical strength and thermal fatigue resistance of the cast iron can be raised.

Description

Make the cast iron that pig iron ingot mould is used

Technical field

The present invention relates to a kind of cast iron that pig iron ingot mould is used that is used to make.

Background technology

Pig iron be molten iron pouring by blast-furnace smelting in metal die, molten iron is through forming after the cooled and solidified.Because the molten iron temperature in the blast furnace is usually at 1480-1500 ℃; Pouring temperature is at 1300-1350 ℃; And metal die very easily fusing under the erosion of high temperature liquid iron; So prior art adopts the mode of recirculated water cooling to reduce the temperature of mould, melts under the erosion of high temperature liquid iron to prevent it.

Yet; Even if recirculated cooling water can reduce the temperature of metal die, but sharply cool off these two kinds repeatedly under the rapid heating and cooling environment, can make the bigger thermal stresses of metal die generation because metal die corrodes with water at high temperature liquid iron; The inwall that is metal die is excessive because of temperature variation; The thermal stresses of its generation is also bigger, and this thermal stresses exercising result is prone to make metal die to produce deformation; If it is relatively poor that the steel grade of making mould bears the ability of this environment, the phenomenon that crackle, scaling loss and pig iron are difficult to the demoulding will appear in this kind metal die.

In the prior art; All adopt QT500-7 or low-alloy refractory cast iron HTRCr as the starting material of making pig iron mould; Though these two kinds of metallic substance have certain resistance toheat; But it is relatively poor relatively that it bears cold and hot exchange, crack, heat-resistant anti-fatigue performance, and under normal conditions, be no more than three months the work-ing life of the mould of manufacturing with above-mentioned metallic substance; Main problem is that when changing ingot mould, blast furnace also needs to stop production, and not only influences the output of processing pig iron, has also improved production cost simultaneously.

Chinese patent 101935803A number disclosed name is called proposition in " as cast condition plate cold punching die steel alloy and ME thereof ": steel alloy comprises carbon 0.9-1.1%; Silicon 0.2-0.4%; Manganese 0.4-0.7%; Chromium 4.8-5.5%; Molybdenum 0.9-1.2%, vanadium 0.1-0.3%, and an amount of copper and REE, its meaning is to utilize noble metals such as manganese, chromium, molybdenum and vanadium to improve its toughness and the voltinism ability of quenching.Though it is this kind steel alloy has preferably physical strength and has performances such as wear-resistant, high temperature resistant and corrosion-resistant,, higher to the cost of manufacture that makes this mould because metals such as molybdenum and vanadium are valuable; Simultaneously, because of in the cast iron during graphite crystallization volume can expand, so the shrinking percentage of cast iron in transport process is little, has good wear resistance and high weakening property with the mould of its making, thereby can prolong its work-ing life.

Summary of the invention

Task of the present invention provides a kind of work-ing life of adding rare earth metal solution cast iron and cast iron that intensity is used its making ingot mould that satisfies mechanical property of utilizing.

The cast iron that making ingot mould proposed by the invention is used comprises the material of following weight percent: carbon 3.6-3.8%; Silicon 1.5-1.8%; Manganese 0.4-0.5%; Chromium 0.4-0.5%; Rare earth 0.015-0.025%; Phosphorus≤0.1%; Sulphur≤0.1%; Surplus is iron and unavoidable impurities.Wherein, rare earth ability crystal grain thinning promotes acicular ferrite to form, if the content of rare earth is unfavorable for that less than 0.015% acicular ferrite forms, and its content is higher than the cost of 0.025% meeting increase cast iron; Manganese has the intensity of raising, toughness in cast iron, reduce the effect of ductile-brittle transition temperature; Adding chromium and manganese can improve the ys and the tensile strength of cast iron in the cast iron.Said rare earth is selected yttrium-base heavy rare earth for use, purifying molten iron more effectively, crystal grain thinning; Improve the comprehensive mechanical property of cast iron, its tensile strength 220～250Mpa, hardness 180～220HB; Metallographic structure: the tiny graphite flake of A type, 98～99% perlite P+1～2% ferritic F.

Cast iron that making ingot mould proposed by the invention is used adds the dense structure that rare earth metal (yttrium-base heavy rare earth) can make cast iron, the graphite refinement, and then can improve the physical strength and the heat-resistant anti-fatigue performance of cast iron.Detect through on-the-spot, the ingot mould that uses this kind cast iron to make, can double than the ingot mould that adopts QT500-7 or low-alloy refractory cast iron HTRCr to make work-ing life, thereby can improve the efficient of making pig iron, can reduce production costs greatly.

Embodiment:

Embodiment 1:

The weight percent of each microalloy is a carbon 3.6% in the cast iron liquid; Silicon 1.8%; Manganese 0.4%; Chromium 0.5%; Rare earth 0.025%; Phosphorus≤0.1%; Sulphur≤0.1%; Surplus is iron and unavoidable impurities, and this impurity is to exist in the iron liquid.

Embodiment 2:

The weight percent of each microalloy is a carbon 3.8% in the cast iron liquid; Silicon 1.5%; Manganese 0.5%; Chromium 0.4%; Rare earth 0.015%; Phosphorus≤0.1%; Sulphur≤0.1%; Surplus is iron and unavoidable impurities, and this impurity is to exist in the iron liquid.

Claims

1. make the cast iron that pig iron ingot mould is used, it is characterized in that comprising the material of following weight percent: carbon 3.6-3.8%; Silicon 1.5-1.8%; Manganese 0.4-0.5%; Chromium 0.4-0.5%; Rare earth 0.015-0.025%; Phosphorus≤0.1%; Sulphur≤0.1%; Surplus is iron and unavoidable impurities.