CN102676855A

CN102676855A - Method for preparing high magnesium aluminium alloy ingot used for forging hubs

Info

Publication number: CN102676855A
Application number: CN2011100625004A
Authority: CN
Inventors: 赵凯志
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-03-11
Filing date: 2011-03-11
Publication date: 2012-09-19

Abstract

The invention relates to a method for preparing a high magnesium aluminium alloy ingot used for forging hubs and belongs to the field of metal material. The formula comprises the following components in percentage by weight: 5-10% of Mg, 6.5-7.5% of Si, 0.05-0.08% of Ca, 0.03-0.04% of Cu, 0.01-0.02% of Mn, 0.1-0.15% of Ti, 0.02-0.03% of Ni, 0.02-0.04% of Sr and the balance of Al. Ca, Cu, Sr and 0.001-0.005% of beryllium are added in alloy liquid so as to enhance the stability and the plasticity of material and enhance the hardness and the tensile strength of the hubs. The method disclosed by the invention comprises the steps of: firstly melting Mg, Al, Si and a covering agent in smelting according to material prescription to 700-720 DEG C, then sequentially adding Ca, Cu, Sr and rare earth intermediate alloy, and continuing to rise the temperature to 740-750 DEG C; adjusting the temperature of the alloy liquid to 720-740 DEG C after the alloy elements are completely melted, adding a refining agent, and rising the temperature to 750-760 DEG C; adopting Al-10Sr deteriorated +Al-5Ti-1B for refining; and adding Ar2 gas for refining and degassing, standing, reducing the temperature to 690-710 DEG C, and casting to form the alloy ingot. The toughness and the creep resistance of the forging high magnesium aluminium alloy can be effectively improved.

Description

Forged hub is with the preparation method of high-magnesium aluminum alloy ingot

Technical field

The invention belongs to automobile manufacturing field, be specifically related to the preparation method of a kind of forged hub with the high-magnesium aluminum alloy ingot.

Background technology

At present, aluminium alloy wheel hub adopts the method for casting or die cast to produce usually, conventional cast moulding method; No matter be counter-pressure casting, low-pressure casting or gravitational casting, all, the gas in the mold cavity can't be drained because of the high velocity turbulent flow motion of its alloy liquid filling die mould; And cause product blank weave construction not fine and close, be easy to generate casting flaws such as loose, folder hole; Its manufacturing cost is high, and the energy and raw materials consumption are bigger.The mechanical property of product and the surface quality of foundry goods can not be fully up to expectations.

Adopt and forge and spin forming method, can efficiently utilize starting material, save production cost.But preparation of its forging and pressing alloy pig is arranged by its castability often, and particularly the castability of the higher duraluminum of magnesium content is extremely unstable, and it mainly shows: during (1) casting, under the even situation of inhomogeneous cooling, be prone to form thermal crack; (2) be prone to form the surface and draw trace and drawing crack; (3) the alloy melt stickiness is bigger, and is mobile poor, is prone to form cold shut.

Summary of the invention

The objective of the invention is to: the preparation method of a kind of forged hub with the high-magnesium aluminum alloy ingot is provided, improves the castability of high-magnesium aluminum alloy in the following manner:

(1) material formula is (weight percent): Mg 5-10%, and Si6.5-7.5%, Ca0.05-0.08%, Cu0.03-0.04%, Mn0.01-0.02%, Ti0.1-0.15%, Ni0.02-0.03%, Sr0.02-0.04%, all the other are Al.The metals such as beryllium that in alloy liquid, added Ca, Cu, Sr and about 0.001-0.005%.With the stability and the plasticity of strongthener, strengthen the hardness and the tensile strength of wheel hub.；

(2) by material prescription magnesium, aluminium, silicon and insulating covering agent are melted to 700-720 ℃ in melting; Add Ca, Cu, Sr and rare earth intermediate alloy then successively; Continue to be warming up to 740-750 ℃, treat that alloying element all after the fusing, is adjusted to 720 ℃～740 ℃ with the alloy liquid temp again;

(3) add refining agent, be warming up to 750-760 ℃; Adopt Al-10Sr to go bad+the Al-5Ti-1B thinning processing;

(4) add Ar2 gas refining degasification, leave standstill, casting temp is controlled at 690-710 ℃, than the high 50-70 of liquidus temperature ℃.

For preventing ingot casting surface heat crackle, casting speed is controlled at 70-75mm/min, and water coolant hydraulic pressure is controlled at 0.08-0.15MPa, is cast as diameter 400-600mm, highly is the alloy pig of 250--300mm.

Because the sodium fragility of high-magnesium aluminum alloy material is prone to make the hot strength reduction of alloy thereby do not use the sodium fusion agent to make insulating covering agent and refining agent easily.

Embodiment

Embodiment 1:

(1) material formula is (weight percent): Mg8%, Si7%, and Ca0.06%, Cu0.035%, Mn0.01%, Ti0.15%, Ni0.02%, Sr0.03%, all the other are Al.The beryllium that in alloy liquid, has added Ca, Cu, Sr and about 0.002%.

(2) by material prescription magnesium, aluminium, silicon and insulating covering agent are melted to 720 ℃ in melting, add Ca, Cu, Sr and rare earth intermediate alloy then successively, continue to be warming up to 740 ℃, treat that alloying element all after the fusing, is adjusted to 720 ℃ with the alloy liquid temp again;

(3) add refining agent, be warming up to 760 ℃; Adopt Al-10Sr to go bad+the Al-5Ti-1B thinning processing;

(4) add Ar2 gas refining degasification, leave standstill, casting temp is controlled at 695 ℃, for preventing ingot casting surface heat crackle, casting speed is controlled at 73mm/min, water coolant hydraulic pressure is controlled at 0.10MPa, is cast as diameter 400mm, highly is the alloy pig of 250mm.

Embodiment 2:

(1) material formula is (weight percent): Mg 7%, Si6.57%, and Ca0.07%, Cu0.04%, Mn0.02%, Ti0.15%, Ni0.02%, Sr0.04%, all the other are Al.The beryllium that in alloy liquid, has added Ca, Cu, Sr and 0.004%.

(2) by material prescription magnesium, aluminium, silicon and insulating covering agent are melted to 710 ℃ in melting, add Ca, Cu, Sr and rare earth intermediate alloy then successively, continue to be warming up to 750 ℃, treat that alloying element all after the fusing, is adjusted to 740 ℃ with the alloy liquid temp again;

(4) add Ar2 gas refining degasification, leave standstill, casting temp is controlled at 710 ℃, for preventing ingot casting surface heat crackle, casting speed is controlled at 75mm/min, water coolant hydraulic pressure is controlled at 0.15MPa, is cast as diameter 600mm, highly is the alloy pig of 250mm.

Claims

1. forged hub is characterized in that with the preparation method of high-magnesium aluminum alloy ingot:

Its prescription is (weight percent): Mg 5-10%, Si6.5-7.5%, Ca0.05-0.08%, Cu0.03-0.04%; Mn0.01-0.02%, Ti0.1-0.15%, Ni0.02-0.03%; Sr0.02-0.04%, all the other are Al, in alloy liquid, have added the beryllium of Ca, Cu, Sr and 0.001-0.005%; With the stability and the plasticity of strongthener, strengthen the hardness and the tensile strength of wheel hub, technical scheme comprises:

(1) by material prescription magnesium, aluminium, silicon and insulating covering agent are melted to 700-720 ℃ in melting; Add Ca, Cu, Sr and rare earth intermediate alloy then successively; Continue to be warming up to 740-750 ℃, treat that alloying element all after the fusing, is adjusted to 720 ℃～740 ℃ with the alloy liquid temp again;

(2) add refining agent, be warming up to 750-760 ℃; Adopt Al-10Sr to go bad+the Al-5Ti-1B thinning processing;

(3) add Ar2 gas refining degasification, leave standstill, casting temp is controlled at 690-710 ℃, than the high 50-70 of liquidus temperature ℃.For preventing ingot casting surface heat crackle, casting speed is controlled at 70-75mm/min, and water coolant hydraulic pressure is controlled at 0.08-0.15MPa, is cast as diameter 400-600mm, highly is the alloy pig of 250-300mm.

2. according to the preparation method of the described forged hub of claim 1, it is characterized in that with the high-magnesium aluminum alloy ingot: casting temp 690-710 ℃, than the high 50-70 of liquidus temperature ℃.

3. according to the preparation method of the described forged hub of claim 1 with the high-magnesium aluminum alloy ingot, it is characterized in that: for preventing ingot casting surface heat crackle, casting speed is controlled at 70-75mm/min, and water coolant hydraulic pressure is controlled at 0.08-0.15MPa.

4. according to the preparation method of the described forged hub of claim 1, it is characterized in that: do not use sodium fusion agent covering and refining with the high-magnesium aluminum alloy ingot.

5. according to the preparation method of the described forged hub of claim 1, it is characterized in that: the beryllium that in prescription, has added about 0.001-0.005% with the high-magnesium aluminum alloy ingot.