CN102407316A

CN102407316A - Casting method for reducing internal shrinkage porosity of alminal cast

Info

Publication number: CN102407316A
Application number: CN2011103837584A
Authority: CN
Inventors: 宋德付
Original assignee: SUZHOU HAURONG NON-FERROUS METALS MANUFACTURING CO LTD
Current assignee: SUZHOU HAURONG NON-FERROUS METALS MANUFACTURING CO LTD
Priority date: 2011-11-28
Filing date: 2011-11-28
Publication date: 2012-04-11

Abstract

The invention relates to a casting method for the alminal, in particular to a casting method for reducing internal shrinkage porosity of an alminal cast. The casting method for reducing internal shrinkage porosity of the alminal cast comprises the following steps of: installing a die; burdening; smelting and deteriorating; refining; pouring; cleaning and processing, wherein the die installing step comprises the procedures of: adding a copper insert in the die corresponding zone of the cast needing to add an extremely cold measure, and adding a venting device on a die mandril; the step of smelting and deteriorating comprises the procedures of: when temperature reaches 700-720DEG C, beginning to add 0.3-0.5% of Al-Ti-B alloy alterant, then adding 0.3-0.5% of refining agent, and stirring for 8-10 minutes; and the pouring step comprises the procedures of: controlling the pouring temperature to 710-720DEG C, carrying out rotary pouring for 8s, keeping the die for 2min, and taking out a piece after the die is opened. The die is improved and the alminal is subjected to deterioration processing in the casting process, so that the problem of internal shrinkage porosity of the cast is solved, and the pressure resistance of the cast is increased.

Description

A kind of casting method that reduces the inner shrinkage porosite of Alar foundry goods

Technical field

The present invention relates to a kind of Alar casting method, particularly relate to a kind of casting method that reduces the inner shrinkage porosite of Alar foundry goods.

Background technology

Al-alloy metal mold casting, its advantage are that cooling velocity is fast, and textura epidermoidea is fine and close, but that its shortcoming is a gas permeability is relatively poor, and thick big position is easy to generate shrinkage porosite, and in Alar, the alloy of cupric class is in casting process, and the shrinkage porosite tendency is big.Because the existence of shrinkage porosite will reduce the effective bearing area of foundry goods, even cause stress concentrated and reduce the physics and the mechanical property of foundry goods greatly.Because the continuity of foundry goods is destroyed, the performances such as air-tightness, corrosion stability of foundry goods are significantly reduced; The roughness of processing back cast(ing) surface improves; Thereby reduce the mechanical performance of foundry goods, need feeding, be employed in the thick large part that possibly occur shrinkage cavity on the foundry goods usually and lay technological measures such as rising head; Position away from rising head is solidified earlier; Then being to solidify near the rising head position, is solidifying of rising head itself at last, but the position that on metal mold, has but is difficult to realize increasing the method for rising head.Simultaneously, approach and the thicker foundry goods of neck for tube wall, except thick large part is easy to generate the shrinkage porosite; Even the tube wall surface thin does not have open defects such as shrinkage porosite, shrinkage cavity, but, can not bear pressure because wall thickness is too thin; After using traditional alterant and al-sr alloy alterant; This situation can not be improved significantly, be still and can't pass pressure test, obviously can not satisfy product requirement.

Summary of the invention

Technical problem:The purpose of this invention is to provide a kind of casting method that reduces the inner shrinkage porosite of Alar foundry goods, through mould is improved and casting process in be that alloy modification is handled to sial, solve the problem of the inner shrinkage porosite of foundry goods, increase the withstand voltage properties of foundry goods.

Technical scheme:A kind of casting method that reduces the inner shrinkage porosite of Alar foundry goods; Comprise: installation mold, batching, melting are rotten, refining, cast, cleaning and processing; Wherein: in the installation mold step, the mould respective regions that need increase extremely cold measure at foundry goods adds copper and inserts, and makes this zone form Quench; Cooling reaches the requirement of no shrinkage porosite rapidly; In the rotten step of melting,, temperature begins to add the Al-Ti-B alloy alterant when reaching 700-720 ℃, and addition is the 0.3-0.5% (wt) of total furnace charge, adds refining agent subsequently, and additional proportion is the 0.3-0.5% (wt) of total furnace charge, stirs 8-10 minute.

In the said installation mold step, increase exhaust apparatus at the ejector pin of die set position.

In the rotten step of said melting, Al-Ti-B alloy alterant addition is 0.4% (wt) of total furnace charge.

In the said refinement step, the refining agent additional proportion is 0.35% (wt) of total furnace charge.

In the said cast step, pouring temperature is controlled at 710-720 ℃, adopts rotary casting, and rotational time 8s stays mould 2min, the die sinking pickup.

Beneficial effect:The mould respective regions that need increase extremely cold measure at foundry goods adds copper and inserts, and can make this place cold soon, thereby make the effective feeding of foundry goods, reaches the requirement of no shrinkage porosite; Increase the exhaust measure at the ejector pin of die set position, solved the problem that the point-like shrinkage porosite appears in the foundry goods part; Use aluminium titanium boron alterant to replace traditional alterant and al-sr alloy alterant; Owing to wherein contain titanium and boron; Can strengthen grain refinement, fundamentally make dense structure, thereby strengthen the withstand voltage properties of foundry goods; Pressure test rises to present 4.5bar by original 1bar still seepage can not occur, has improved casting yield.

The specific embodiment

Embodiment:

A kind of casting method that reduces the inner shrinkage porosite of Alar foundry goods comprises the steps:

1, installation mold, the mould respective regions that need increase extremely cold measure in the thick large part of foundry goods adds copper and inserts, and increases exhaust apparatus in the ejector pin of die set position.

2, batching is carried out melting, when temperature arrives 720 ℃ of left and right sides, begins to add alterant AlTi ₁₀Be ₅(available from Xuzhou gold Titanium Metal Inc.), addition is 0.4%, for rotten qualified, additional proportion was that 0.35% refining agent carries out refining then, stirs 8-10 minute when a cast appearance piece afterwards, check modification effect, fracture were shown as silvery white velvet shape.

3, cast, experimental material composition before the cast is poured into a mould after qualified, and pouring temperature is controlled at 710-720 ℃, rotary casting, rotational time 8 seconds afterwards, stayed mould 2 minutes, the die sinking pickup.

4, process check finished surface defective, air-tightness, voltage endurance capability after the cleaning.

Test result such as following table:

Under the situation of surface roughness of the product of original cast processing back 6.3, can visual blemish, shrinkage cavity is passed through voltage-withstand test and can only be reached the pressure of 1Bar, and still has the seepage more than 50%.But through the foundry goods after improving, roughness reaches at 1.6 o'clock after processing, can't see blemish, can reach the pressure of 4.5Bar through voltage-withstand test, and not have seepage.

Claims

1. casting method that reduces the inner shrinkage porosite of Alar foundry goods; Comprise: installation mold, batching, melting are rotten, refining, cast, cleaning and processing; It is characterized in that: in the installation mold step, the mould respective regions that need increase extremely cold measure at foundry goods adds copper and inserts; In the rotten step of melting,, temperature begins to add the Al-Ti-B alloy alterant when reaching 700-720 ℃, and addition is the 0.3-0.5% (wt) of total furnace charge, adds refining agent subsequently, and additional proportion is the 0.3-0.5% (wt) of total furnace charge, stirs 8-10 minute.

2. a kind of casting method that reduces the inner shrinkage porosite of Alar foundry goods according to claim 1 is characterized in that: increase exhaust apparatus at the ejector pin of die set position.

3. a kind of casting method that reduces the inner shrinkage porosite of Alar foundry goods according to claim 1 and 2, it is characterized in that: Al-Ti-B alloy alterant addition is 0.4% (wt) of total furnace charge.

4. a kind of casting method that reduces the inner shrinkage porosite of Alar foundry goods according to claim 1 and 2, it is characterized in that: the refining agent additional proportion is 0.35% (wt) of total furnace charge.

5. a kind of casting method that reduces the inner shrinkage porosite of Alar foundry goods according to claim 1 is characterized in that: in the cast step, pouring temperature is controlled at 710-720 ℃, adopts rotary casting, and rotational time 8s stays mould 2min, the die sinking pickup.